Vista Gold 8K Regulation FD Disclosure | VGZ 28 Oct 20

Exhibit 99.1

Report to: 7961 Shaffer Parkway, Suite 5 | Littleton, CO 80127 Phone: (720) 981-1185 NI 43-101 Technical Report Mt Todd Gold Project 50,000 tpd Preliminary Feasibility Study Northern Territory, Australia PROJECT NO.: 117-8348001 PREPARED BY: Rex Clair Bryan, Ph.D., SME RM Anthony Clark, P.E., P.Eng Thomas L. Dyer, P.E., SME RM April Hussey, P.E. Chris Johns, M.Sc., P.Eng Deepak Malhotra, Ph.D., SME RM Jessica I. Monasterio, P.E. Zvonimir Ponos, BE, MIEAust, CPeng, NER David M. Richers, Ph.D., SME RM, CPG Vicki J. Scharnhorst, P.E., LEED AP Keith Thompson, CPG, member AIPG 350 Indiana Street, Suite 500 | Golden, CO 80401 Phone: 303-217-5700 | Fax: 303-217-5705

Report to: 7961 Shaffer Parkway, Suite 5 | Littleton, CO 80127 Phone: (720) 981-1185 NI 43-101 Technical Report Mt Todd Gold Project 50,000 tpd Preliminary Feasibility Study Northern Territory, Australia PROJECT NO: 117-8348001 EFFECTIVE DATE: September 10, 2019 ISSUE DATE: October 7, 2019 AMENDED DATE: September 22, 2020 350 Indiana Street, Suite 500 | Golden, CO 80401 Phone: 303-217-5700 | Fax: 303-217-5705

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 i FORWARD-LOOKING STATEMENTS This Technical Report contains forward-looking statements within the meaning of the U.S. Securities Act of 1933, as amended, and U.S. Securities Exchange Act of 1934, as amended, and forward-looking information within the meaning of Canadian securities laws. All statements, other than statements of historical facts, included in this Technical Report that address activities, events or developments that Vista expects or anticipates will or may occur in the future, including such things as, the Company’s continued work on the Mt Todd gold project; that process improvements will result in lower operating costs, reduced power consumption, increased gold recovery and higher gold production; estimates of mineral reserves and resources; projected project economics, including anticipated production, average cash costs, before and after-tax NPV, IRR, capital requirements and expenditures, gold recovery after-tax payback, operating costs, average tonnes per day milling, mining methods procedures, estimated gold recovery, project design, and life of mine; that the Project is an advanced stage development project; average annual production overtime; commencement of commercial production; timing for construction and commissioning; exploration of new deposits at Mt Todd and the surrounding exploration areas; size of final product through the high pressure grinding roll crusher; potential costs or savings related to gas price; ability to convert Quigleys estimated mineral resources to proven or probable mineral reserves; grade of minerals at the Quigleys deposit; ability to add higher grade feed from the Quigleys deposit to the Project in its mid years; timing for and completion of the NI 43-101 technical report for the PFS; and other such matters are forward-looking statements and forward-looking information. The material factors and assumptions used to develop the forward-looking statements and forward-looking information contained in this Technical Report include the following: the accuracy of the results of the PFS, mineral resource and reserve estimates, and exploration and assay results; the terms and conditions of the Company’s agreements with contractors and Vista’s approved business plan; the anticipated timing and completion of a feasibility study on the Project and permissions including approval of the MMP; the potential occurrence of certain threatened species of flora, vegetation, and fauna within the mine site; the anticipated receipt of required permits; no change in laws that materially impact mining development or operations of a mining business; the potential occurrence and timing of a production decision; the anticipated gold production at the Project; the life of any mine at the Project; all economic projections relating to the Project, including estimated cash cost, NPV, IRR, and initial capital requirements; and Vista’s goal of becoming a gold producer. When used in this Technical Report, the words “optimistic,” “potential,” “indicate,” “expect,” “intend,” “plans,” “hopes,” “believe,” “may,” “will,” “if,” “anticipate,” and similar expressions are intended to identify forward-looking statements and forward-looking information. These statements involve known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of Vista to be materially different from any future results, performance or achievements expressed or implied by such statements. Such factors include, among others, uncertainty of mineral resource estimates, estimates of results based on such mineral resource estimates; risks relating to cost increases for capital and operating costs; risks related to the timing and the ability to obtain the necessary permits, risks of shortages and fluctuating costs of equipment or supplies; risks relating to fluctuations in the price of gold; the inherently hazardous nature of mining-related activities; potential effects on Vista’s operations of environmental regulations in the countries in which it operates; risks due to legal proceedings; risks relating to political and economic instability in certain countries in which it operates; as well as those factors discussed under the headings “Note Regarding Forward-Looking Statements” and “Risk Factors” in Vista’s Annual Report Form 10-K as filed in February 2019 and other documents filed with the U.S. Securities and Exchange Commission and Canadian securities regulatory authorities. Although Vista has attempted to identify important factors that could cause actual results to differ materially from those described in forward-looking statements and forward-looking information, there may be other factors that cause results not to be as anticipated, estimated or intended. Except as required by law, Vista assumes no

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 ii obligation to publicly update any forward-looking statements or forward-looking information; whether as a result of new information, future events or otherwise. Cautionary Note to United States Investors The United States Securities and Exchange Commission (“SEC”) limits disclosure for U.S. reporting purposes to mineral deposits that a company can economically and legally extract or produce. This Technical Report uses the terms “Proven reserves” and “Probable reserves”. Reserve estimates contained in this Technical Report are made pursuant to NI 43-101 standards in Canada and do not represent reserves under the standards of the SEC’s Industry Guide 7 and may not constitute reserves under the SEC’s newly adopted disclosure rules to modernize mineral property disclosure requirements, which became effective February 25, 2019 and will be applicable to the Company in its annual report for the fiscal year ending December 31, 2021. Under the currently applicable SEC Industry Guide 7 standards, a “final” or “bankable” feasibility study is required to report reserves, the three-year historical average price is used in any reserve or cash flow analysis to designate reserves and all necessary permits and government approvals must be filed with the appropriate governmental authority. Additionally, this Technical Report uses the terms “Measured resources”, “Indicated resources”, and “Measured & Indicated resources”. Vista advises U.S. investors that while these terms are Canadian mining terms as defined in accordance with NI 43-101, such terms are not recognized under SEC Industry Guide 7 and normally are not permitted to be used in reports and registration statements filed with the SEC. Mineral resources described in this Technical Report have a great amount of uncertainty as to their economic and legal feasibility. The SEC normally only permits issuers to report mineralization that does not constitute SEC Industry Guide 7 compliant “reserves” as in-place tonnage and grade, without reference to unit measures. The term “contained gold ounces” used in this Technical Report is not permitted under the rules of the SEC. “Inferred resources” have a great amount of uncertainty as to their existence, and great uncertainty as to their economic and legal feasibility. It cannot be assumed that any or all part of an Inferred resource will ever be upgraded to a higher category. U.S. Investors are cautioned not to assume that any part or all of mineral deposits in these categories will ever be converted into SEC Industry Guide 7 reserves. NOTE All references to the term “ore” contained in this Technical Report refer to mineral reserves, not mineral resources.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 iii TABLE OF CONTENTS 1.0 SUMMARY .................................................................................................................................................... 1 1.1 Introduction .................................................................................................................................................... 1 1.2 Location ........................................................................................................................................................... 2 1.3 Property Description ....................................................................................................................................... 3 1.4 Geology and Mineralization ............................................................................................................................ 8 1.5 Mineral Resource Estimate ............................................................................................................................. 8 1.6 Mineral Reserve Estimates ............................................................................................................................ 10 1.6.1 Heap Leach Reserve Estimate .......................................................................................................... 11 1.7 Mining Methods ............................................................................................................................................ 12 1.8 Metallurgy ..................................................................................................................................................... 13 1.9 Mineral Processing ........................................................................................................................................ 15 1.10 Project Infrastructure .................................................................................................................................. 15 1.11 Market Studies and Contracts ..................................................................................................................... 16 1.11.1 Markets .......................................................................................................................................... 16 1.11.2 Contracts ........................................................................................................................................ 16 1.12 Social and Environmental Aspects .............................................................................................................. 17 1.12.1 Existing Environmental and Social Information ............................................................................. 17 1.12.2 Social or Community Requirements ............................................................................................... 17 1.12.3 Approvals, Permits and Licenses .................................................................................................... 18 1.13 Capital and Cost Estimates .......................................................................................................................... 19 1.13.1 Capital Cost Estimates .................................................................................................................... 19 1.13.2 Operating Cost Estimates ............................................................................................................... 21 1.14 Financial Analysis ........................................................................................................................................ 22 1.14.1 Financial Analysis ........................................................................................................................... 22 1.15 Conclusions and Recommendations ........................................................................................................... 22 1.15.1 Feasibility Study ............................................................................................................................. 23 1.15.2 Geology and Resources .................................................................................................................. 23 1.15.3 Mineral Reserve and Mine Planning .............................................................................................. 24 1.15.4 Mineral Processing ......................................................................................................................... 24 1.15.5 Infrastructure ................................................................................................................................. 25 1.15.6 Environmental and Social Impacts ................................................................................................. 26 1.15.7 Results of the Site-wide Water Balance Model .............................................................................. 27 1.15.8 Groundwater Hydrology and Mine Dewatering ............................................................................. 27 1.15.9 Process Plant Geotechnical Investigation ...................................................................................... 28 1.15.10 TSF Design .................................................................................................................................... 28 1.15.11 Process ......................................................................................................................................... 28 1.15.12 Geochemical Analyses .................................................................................................................. 28 2.0 INTRODUCTION ........................................................................................................................................... 29 2.1 Background Information ............................................................................................................................... 29 2.2 Terms of Reference and Purpose of the Report ........................................................................................... 30 2.3 Sources of Information.................................................................................................................................. 30 2.4 Units of Measure ........................................................................................................................................... 30 2.5 Detailed Personal Inspections ....................................................................................................................... 30 3.0 RELIANCE ON OTHER EXPERTS ..................................................................................................................... 32

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 iv 4.0 PROPERTY DESCRIPTION AND LOCATION ..................................................................................................... 33 4.1 Location ......................................................................................................................................................... 33 4.2 Property Description ..................................................................................................................................... 33 4.3 Lease and Royalty Structure .......................................................................................................................... 33 4.4 Risks .............................................................................................................................................................. 38 5.0 ACCESSIBILITY, CLIMATE, LOCAL RESOURCES, INFRASTRUCTURE AND PHYSIOGRAPHY ................................ 39 5.1 Accessibility ................................................................................................................................................... 39 5.2 Climate and Physiography ............................................................................................................................. 39 5.3 Local Resources and Infrastructure ............................................................................................................... 39 5.4 Topography, Elevation and Vegetation ......................................................................................................... 39 6.0 HISTORY ...................................................................................................................................................... 40 6.1 History of Previous Exploration ..................................................................................................................... 41 6.2 Historic Drilling .............................................................................................................................................. 43 6.2.1 Batman Deposit ................................................................................................................................ 43 6.2.2 Drillhole Density and Orientation ..................................................................................................... 44 6.2.3 Quigleys ............................................................................................................................................ 45 6.3 Historic Sampling Method and Approach ..................................................................................................... 47 6.4 Historic Sample Preparation, Analysis and Security ...................................................................................... 47 6.4.1 Sample Analysis ................................................................................................................................ 47 6.4.2 Check Assays .................................................................................................................................... 48 6.4.3 Security ............................................................................................................................................. 48 6.5 Historic Process Description .......................................................................................................................... 48 6.6 Technical Problems with Historical Process Flowsheet ................................................................................ 49 6.6.1 Crushing ........................................................................................................................................... 49 6.6.2 Flotation Circuit ................................................................................................................................ 52 6.6.3 CIL of Flotation Concentrate and Tailings ........................................................................................ 52 7.0 GEOLOGICAL SETTING AND MINERALIZATION .............................................................................................. 53 7.1 Geological and Structural Setting .................................................................................................................. 53 7.2 Local Geology ................................................................................................................................................ 54 7.3 Mineralization ............................................................................................................................................... 57 7.3.1 Batman Deposit ................................................................................................................................ 57 7.3.2 Quigleys Deposit ............................................................................................................................... 58 8.0 DEPOSIT TYPES ............................................................................................................................................ 60 9.0 EXPLORATION ............................................................................................................................................. 61 9.1 Golden Eye Target ......................................................................................................................................... 63 9.2 RKD Target..................................................................................................................................................... 64 9.3 Silver Spray Target ........................................................................................................................................ 64 9.4 Snowdrop Target ........................................................................................................................................... 64 9.5 Sample Preparation Methods and Quality Control (QC) Measures .............................................................. 65 9.6 Relevant Information Regarding Sample Preparation, Assaying, and Analytical Procedures ....................... 65 10.0 DRILLING ................................................................................................................................................... 67 10.1 Summary History of Batman Drilling 1988-2017......................................................................................... 67 10.1.1 Vista Drilling Detail 2012-2017 ...................................................................................................... 68

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 v 10.2 Summary History of Quigleys Drilling 1975-2011 ....................................................................................... 99 10.3 Drilling Procedures .................................................................................................................................... 118 10.4 Sampling .................................................................................................................................................... 119 10.5 Summary and Interpretation of Relevant Results ..................................................................................... 119 11.0 SAMPLE PREPARATION, ANALYSES AND SECURITY ................................................................................... 121 11.1 Sample Preparation ................................................................................................................................... 121 11.2 Sample Analyses ........................................................................................................................................ 122 11.3 Sample Security ......................................................................................................................................... 128 12.0 DATA VERIFICATION ................................................................................................................................ 129 12.1 Drill Core and Geologic Logs ..................................................................................................................... 129 12.2 Topography ............................................................................................................................................... 129 12.3 Verification of Analytical Data ................................................................................................................... 129 12.3.1 Latest Drilling Data Verification ................................................................................................... 132 13.0 MINERAL PROCESSING AND METALLURGICAL TESTING ............................................................................ 137 13.1 Summary ................................................................................................................................................... 137 13.2 Historic Metallurgical Test Programs ........................................................................................................ 137 13.3 2017 Metallurgical Testwork ..................................................................................................................... 139 13.3.1 HPGR Testing at Thyssen-Krupp Industries (TKI) .......................................................................... 139 13.3.2 Tomra/Outotec Ore Sorting Testwork .......................................................................................... 141 13.3.3 Preparation of Composites for Metallurgical Testwork ............................................................... 144 13.3.4 Mineralogical Study ..................................................................................................................... 144 13.3.5 Head Analyses .............................................................................................................................. 145 13.3.6 Abrasion Indices ........................................................................................................................... 146 13.3.7 Bond Ball Mill Work Indices .......................................................................................................... 147 13.3.8 Leach Tests ................................................................................................................................... 148 13.3.9 Cyanide Destruction ..................................................................................................................... 151 13.3.10 Thickening Tests ......................................................................................................................... 152 13.4 2018/2019 Metallurgical Test Work ......................................................................................................... 152 13.4.1 HPGR Testing at Thyssen-Krupp Industries (TKI) ...................................................................... 155 13.4.2 HPGR Testing at WEIR Minerals ................................................................................................ 155 13.4.3 Tomra/Outotec Ore Sorting Test Work ........................................................................................ 155 13.4.4 Steinert Ore Sorting Test Work .................................................................................................... 157 13.4.5 Preparation of Composites for Metallurgical Test Work and Head Analyses .............................. 159 13.4.6 Bond's Ball Mill Work Indices ....................................................................................................... 159 13.4.7 Primary Grind ............................................................................................................................... 160 13.4.8 Fine Grind ..................................................................................................................................... 160 13.4.9 Leach Feed Thickener ................................................................................................................... 161 13.4.10 Leach Agitator Design and Power Requirements ....................................................................... 161 13.4.11 Leach Tests ................................................................................................................................. 161 13.4.12 Thickening Tests on Leach Residue ............................................................................................ 165 13.4.13 Cyanide Destruction ................................................................................................................... 165 13.5 Process Flowsheet ..................................................................................................................................... 166 14.0 MINERAL RESOURCE ESTIMATES .............................................................................................................. 169 14.1 Introduction .............................................................................................................................................. 169 14.2 Geologic Modeling of the Batman Deposit ............................................................................................... 171 14.2.1 Batman Deposit Density Data ...................................................................................................... 175

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 vi 14.2.2 Grade Capping ............................................................................................................................. 175 14.3 Batman Block Model Parameters ............................................................................................................. 175 14.3.1 Geostatistics of the Batman Deposit ............................................................................................ 176 14.4 Batman Estimation Quality ....................................................................................................................... 188 14.5 Modeling of the Quigleys Deposit ............................................................................................................. 191 14.5.1 Quigleys Exploration Database .................................................................................................... 192 14.5.2 Quigleys Block Model Parameters................................................................................................ 192 14.6 Existing Heap Leach Gold Resource .......................................................................................................... 198 14.7 Relevant Factors Affecting Resource Estimates ........................................................................................ 200 15.0 MINERAL RESERVES ................................................................................................................................. 201 15.1 Pit Optimization ........................................................................................................................................ 201 15.1.1 Economic Parameters .................................................................................................................. 201 15.1.2 Slope Parameters ......................................................................................................................... 202 15.1.3 Pit-Optimization Results ............................................................................................................... 204 15.1.4 Ultimate Pit Limit Selection .......................................................................................................... 206 15.2 Pit Designs ................................................................................................................................................. 206 15.2.1 Bench Height ................................................................................................................................ 206 15.2.2 Pit Design Slopes .......................................................................................................................... 207 15.2.3 Haulage Roads ............................................................................................................................. 208 15.2.4 Ultimate Pit .................................................................................................................................. 208 15.2.5 Pit Phasing .................................................................................................................................... 210 15.3 Cutoff Grade .............................................................................................................................................. 214 15.4 Dilution ...................................................................................................................................................... 214 15.5 Reserves .................................................................................................................................................... 214 15.6 Heap Leach Reserve Estimate ................................................................................................................... 217 16.0 MINING METHODS .................................................................................................................................. 218 16.1 Methods .................................................................................................................................................... 218 16.2 Site Landforms and Impoundments .......................................................................................................... 218 16.3 Waste Material Definition ......................................................................................................................... 219 16.4 Mine-Waste Facilities ................................................................................................................................ 219 16.5 Mine-Production Schedule ........................................................................................................................ 221 16.6 Equipment Selection and Productivities ................................................................................................... 226 16.7 Mine Personnel ......................................................................................................................................... 230 17.0 RECOVERY METHODS .............................................................................................................................. 234 17.1 Process Design Criteria .............................................................................................................................. 234 17.2 Flow Sheet Development .......................................................................................................................... 235 17.2.1 Crushing Modeling ....................................................................................................................... 235 17.2.2 Primary Crusher ............................................................................................................................ 237 17.2.3 Secondary Crushers ...................................................................................................................... 237 17.2.4 HPGR ............................................................................................................................................ 237 17.2.5 Ore Sorting ................................................................................................................................... 237 17.2.6 Grinding Modeling ....................................................................................................................... 237 17.2.7 Thickener / Leach / CIP Design ..................................................................................................... 237 17.3 Description of Process Areas ..................................................................................................................... 238 17.3.1 Area 3100 – Crushing Circuit Availabilities ................................................................................... 238

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 vii 17.3.2 Area 3200 – Coarse Ore Stockpile, Reclaim, HPGR and Ore Sorting ............................................ 239 17.3.3 Area 3300 – Grinding and Classification ...................................................................................... 239 17.3.4 Area 3400 – Pre-Leach Thickening, Leach Conditioning, Leach and CIP ...................................... 240 17.3.5 Area 3500 – Desorption, Goldroom and Carbon Regeneration.................................................... 240 17.3.6 Area 3600 – Detoxification and Tailings ...................................................................................... 240 17.3.7 Area 3700 – Reagents .................................................................................................................. 241 17.3.8 Area 3800 – Process Plant Services .............................................................................................. 241 17.4 Process Water ........................................................................................................................................... 242 17.4.1 Process Compressed Air ............................................................................................................... 242 17.5 Plant Mobile Equipment ........................................................................................................................... 243 18.0 PROJECT INFRASTRUCTURE...................................................................................................................... 244 18.1 Facility 2000 – Mine .................................................................................................................................. 244 18.1.1 Area 2300 – Mine Support Facilities............................................................................................. 244 18.1.2 Area 2400 – Mine Support Services .............................................................................................. 246 18.2 Facility 4000 – Project Services ................................................................................................................. 247 18.2.1 Area 4100 – Water Supply ........................................................................................................... 247 18.2.2 Area 4200 – Power Supply ........................................................................................................... 248 18.2.3 Area 4300 – Communications ...................................................................................................... 249 18.2.4 Area 4400 – Tailings Dam ............................................................................................................ 250 18.2.5 Area 4500 – Waste Disposal ........................................................................................................ 251 18.2.6 Area 4600 – Plant Mobile Equipment .......................................................................................... 251 18.3 Facility 5000 – Project Infrastructure ........................................................................................................ 252 18.3.1 Area 5100 – Site Preparation ....................................................................................................... 252 18.3.2 Area 5200 – Support Buildings ..................................................................................................... 252 18.3.3 Area 5400 – Heavy Lift Cranage ................................................................................................... 255 18.3.4 Area 5600 – Bulk Transport .......................................................................................................... 255 18.3.5 Area 5800 – Communications ...................................................................................................... 255 18.4 Facility 6000 – Permanent Accommodation ............................................................................................. 256 18.4.1 Area 6100 – Personnel Transport ................................................................................................. 256 18.5 Facility 7000 – Site Establishment and Early Works .................................................................................. 256 18.5.1 Area 7300 – Construction Camp ................................................................................................... 256 18.6 Facility 8000 – Management, Engineering, EPCM Services ...................................................................... 257 18.6.1 Area 8100 – EPCM Services .......................................................................................................... 257 18.6.2 Area 8200 – External Consultants/Testing ................................................................................... 257 18.6.3 Area 8300 – Commissioning ......................................................................................................... 257 18.6.4 Area 8400 – Owners Engineering/Management ......................................................................... 257 18.6.5 Area 8800 – License, Fees and Legal Costs ................................................................................... 257 18.6.6 Area 8900 – Project Insurances .................................................................................................... 258 18.7 Facility 9000 – Preproduction Costs .......................................................................................................... 258 18.7.1 Area 9100 – Preproduction Labor ................................................................................................ 258 18.7.2 Area 9200 – Commissioning Expenses ......................................................................................... 258 18.7.3 Area 9300 – Capital Spares .......................................................................................................... 258 18.7.4 Area 9400 – Stores and Inventories ............................................................................................. 258 18.7.5 Area 9600 – Working Capital and Finance ................................................................................... 258 18.7.6 Area 9700 – Escalation and Foreign Currency Exchange ............................................................. 259 18.7.7 Area 9800 – Contingency Provision .............................................................................................. 259 18.7.8 Area 9900 – Management Reserve Provision .............................................................................. 259 18.8 Electric Power Plant .................................................................................................................................. 259 18.8.1 Generation Option Selection ........................................................................................................ 261

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 viii 18.8.2 Mt Todd Electrical ........................................................................................................................ 261 19.0 MARKET STUDIES AND CONTRACTS ......................................................................................................... 265 19.1 Markets ..................................................................................................................................................... 265 19.2 Contracts ................................................................................................................................................... 265 20.0 ENVIRONMENTAL STUDIES, PERMITTING, AND SOCIAL OR COMMUNITY IMPACT .................................... 266 20.1 Environmental Studies .............................................................................................................................. 266 20.1.1 Flora and Vegetation .................................................................................................................... 267 20.1.2 Nationally Threatened Fauna ....................................................................................................... 267 20.1.3 Migratory and / or Marine Species .............................................................................................. 267 20.1.4 National Heritage Places .............................................................................................................. 267 20.2 Waste and Tailings Disposal, Site Monitoring and Water Management .................................................. 268 20.2.1 Waste Rock Disposal .................................................................................................................... 268 20.2.2 Tailings Disposal ........................................................................................................................... 268 20.2.3 Site Monitoring............................................................................................................................. 268 20.2.4 Water Management..................................................................................................................... 268 20.3 Permitting and Authorizations .................................................................................................................. 270 20.4 Social or Community Requirements.......................................................................................................... 271 20.5 Mine Reclamation and Closure ................................................................................................................. 272 20.5.1 Batman Pit ................................................................................................................................... 273 20.5.2 Waste Rock Dump ........................................................................................................................ 273 20.5.3 Tailings Disposal Facility .............................................................................................................. 273 20.5.4 Processing Plant and Pad Area ..................................................................................................... 274 20.5.5 Heap Leach Pad and Pond ............................................................................................................ 274 20.5.6 Low Grade Ore Stockpile .............................................................................................................. 275 20.5.7 Mine Roads .................................................................................................................................. 275 20.5.8 Water Storage Ponds ................................................................................................................... 275 20.5.9 Low Permeability Borrow Area ..................................................................................................... 275 20.5.10 Closure Cost Estimate ................................................................................................................. 276 21.0 CAPITAL AND OPERATING COSTS ............................................................................................................. 277 21.1 Capital Cost ............................................................................................................................................... 277 21.1.1 Mining (MDA) ............................................................................................................................... 279 21.1.2 CIP Process and Infrastructure (TTP) ............................................................................................ 284 21.1.3 Power Plant (POWER Engineers) .................................................................................................. 293 21.1.4 Mine Dewatering (Tetra Tech) ..................................................................................................... 294 21.1.5 Reclamation and Closure (Tetra Tech) ......................................................................................... 294 21.1.6 Water Treatment Plant (Tetra Tech) ............................................................................................ 295 21.1.7 Raw Water Dam (Tetra Tech) ....................................................................................................... 295 21.1.8 Tailings Storage Facilities (Tetra Tech) ......................................................................................... 296 21.2 Operating Costs ......................................................................................................................................... 297 21.2.1 Mining (MDA) ............................................................................................................................... 298 21.2.2 Mine Dewatering (Tetra Tech) ..................................................................................................... 301 21.2.3 CIP Process and G&A (TTP) ........................................................................................................... 301 21.2.4 Power Plant (POWER Engineers) .................................................................................................. 306 21.2.5 Water Treatment Plant (Tetra Tech) ............................................................................................ 308 21.2.6 Tailings Storage Facilities (Tetra Tech) ......................................................................................... 308 21.2.7 General & Administrative ............................................................................................................. 308 22.0 ECONOMIC ANALYSIS .............................................................................................................................. 309 22.1 Principal Assumptions ............................................................................................................................... 309

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 ix 22.2 LoM Production ......................................................................................................................................... 310 22.3 Capital Costs .............................................................................................................................................. 312 22.3.1 2000 Mining ................................................................................................................................. 313 22.3.2 3000 Process Plant ....................................................................................................................... 313 22.3.3 4000 Project Services.................................................................................................................... 314 22.3.4 5000 Project Infrastructure .......................................................................................................... 315 22.3.5 6000 Permanent Accommodation ............................................................................................... 315 22.3.6 7000 Site Establishment & Early Works ....................................................................................... 316 22.3.7 8000 Management, Engineering, EPCM Services ......................................................................... 316 22.3.8 9000 Pre-Production Costs ........................................................................................................... 317 22.3.9 1000 Asset Sale ............................................................................................................................ 317 22.4 Operating Costs ......................................................................................................................................... 318 22.4.1 Open Pit Mining ........................................................................................................................... 319 22.4.2 CIP Process Plant .......................................................................................................................... 320 22.4.3 Water Treatment Plant ................................................................................................................ 320 22.4.4 Tailings ......................................................................................................................................... 321 22.4.5 General & Administrative ............................................................................................................. 321 22.4.6 JAAC Royalty ................................................................................................................................. 322 22.4.7 Refining Costs ............................................................................................................................... 322 22.4.8 Operating Cost Inputs .................................................................................................................. 322 22.5 Economic Results ...................................................................................................................................... 336 22.5.1 Taxes, Royalties ............................................................................................................................ 340 22.5.2 Sensitivity ..................................................................................................................................... 342 23.0 ADJACENT PROPERTIES ............................................................................................................................ 344 24.0 OTHER RELEVANT DATA AND INFORMATION ........................................................................................... 345 24.1 Process Plant Geotechnical ....................................................................................................................... 345 24.2 Water Management .................................................................................................................................. 346 24.2.1 Site-wide Water Balance .............................................................................................................. 346 24.2.2 Wet Infrastructure ........................................................................................................................ 349 24.3 Geochemistry ............................................................................................................................................ 356 24.4 Surface Water Hydrology .......................................................................................................................... 358 24.5 Regional Groundwater Model and Mine Dewatering ............................................................................... 358 24.5.1 Regional and Site Hydrogeology .................................................................................................. 359 24.5.2 Regional Numerical Groundwater Flow Model ............................................................................ 360 24.5.3 Inflow Estimates ........................................................................................................................... 361 24.5.4 Mine Dewatering ......................................................................................................................... 361 24.6 Project Implementation ............................................................................................................................ 365 24.6.1 Project Implementation Strategy ................................................................................................. 365 24.6.2 Project Organization .................................................................................................................... 365 24.6.3 EPCM Management ..................................................................................................................... 368 24.6.4 Engineering .................................................................................................................................. 368 24.6.5 EPCM Controls .............................................................................................................................. 368 24.6.6 Procurement ................................................................................................................................. 369 24.6.7 Construction Management .......................................................................................................... 376 24.6.8 Commissioning ............................................................................................................................. 376 24.6.9 Temporary Construction Facilities ................................................................................................ 378 24.6.10 Industrial Relations .................................................................................................................... 378 24.6.11 Health and Safety ....................................................................................................................... 378 24.6.12 Environment ............................................................................................................................... 380

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 x 24.6.13 Schedule ..................................................................................................................................... 380 25.0 INTERPRETATION AND CONCLUSIONS ...................................................................................................... 384 25.1 Project Risks .............................................................................................................................................. 384 25.2 Geology and Resources ............................................................................................................................. 385 25.3 Mineral Reserve and Mine Planning ......................................................................................................... 386 25.4 Mineral Processing .................................................................................................................................... 387 25.5 Infrastructure ............................................................................................................................................ 387 25.5.1 Site Preparation............................................................................................................................ 387 25.5.2 Support Buildings ......................................................................................................................... 387 25.5.3 Access Roads Parking and Laydown ............................................................................................. 387 25.5.4 Heavy Lifts .................................................................................................................................... 387 25.5.5 Bulk Transport .............................................................................................................................. 388 25.5.6 Communications .......................................................................................................................... 388 25.6 Project Services ......................................................................................................................................... 388 25.7 Environmental and Social Conclusions ...................................................................................................... 388 25.7.1 Existing Body of Work .................................................................................................................. 388 25.7.2 Environmental Impact Study and Approvals ................................................................................ 388 25.7.3 Social or Community Impacts ....................................................................................................... 388 25.8 Results of the Site-wide Water Balance Model ......................................................................................... 389 26.0 RECOMMENDATIONS .............................................................................................................................. 390 26.1 Feasibility Study ........................................................................................................................................ 390 26.2 Resource and Exploration ......................................................................................................................... 390 26.3 Mining Risks and Opportunities ................................................................................................................ 390 26.3.1 Opportunities ............................................................................................................................... 390 26.3.2 Risks ............................................................................................................................................. 390 26.4 Environmental Studies .............................................................................................................................. 391 26.5 Site-wide Water Balance ........................................................................................................................... 391 26.6 Groundwater Hydrology and Mine Dewatering ........................................................................................ 392 26.7 Process Plant Geotechnical Investigation Recommendations .................................................................. 392 26.7.1 Crushing/Screening/Grinding/HPGR/Sorting ............................................................................... 392 26.7.2 Thickener/Leach/CIP .................................................................................................................... 392 26.7.3 Stockpile & Reclaim ...................................................................................................................... 393 26.8 Tailings Facility Design .............................................................................................................................. 393 26.8.1 TSF Construction Schedule ........................................................................................................... 393 26.8.2 Investigation of TSF1 Drainage Features ..................................................................................... 393 26.8.3 Geotechnical Investigation and Assessment ................................................................................ 393 26.8.4 Waste Rock Testing ...................................................................................................................... 393 26.8.5 Consolidation/Seepage Modeling ................................................................................................ 393 26.8.6 Water Balance .............................................................................................................................. 394 26.8.7 TSF Consequence Classification .................................................................................................... 394 26.9 Process Operating Costs ............................................................................................................................ 394 26.10 Geochemical Analyses ............................................................................................................................. 394 26.11 Process Parameter Optimization ............................................................................................................ 394 27.0 REFERENCES ............................................................................................................................................ 395

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 xi 28.0 CERTIFICATE OF QUALIFIED PERSON ........................................................................................................ 400 28.1 Qualifications of Consultants .................................................................................................................... 400 28.2 Table of Responsibility .............................................................................................................................. 401 LIST OF TABLES Table 1-1: PFS Highlights ............................................................................................................................................... 2 Table 1-2: Description of Landforms and Impoundments ............................................................................................ 5 Table 1-3: Statement of Mineral Resources Estimates ................................................................................................. 9 Table 1-4: Statement of Mineral Reserve Estimate .................................................................................................... 11 Table 1-5: Initial Economic Parameters ...................................................................................................................... 12 Table 1-6: WhittleTM Pit Optimization Results –Using 0.40 g-Au/t Cutoff .................................................................. 13 Table 1-7: Headline Design Criteria ............................................................................................................................ 15 Table 1-8: Mt Todd Permit Status ............................................................................................................................... 18 Table 1-9: Estimated Capital Cost Summary (US$000s) ............................................................................................. 20 Table 1-10: Estimated LoM Operating Costs (US$) ..................................................................................................... 21 Table 1-11: Estimated Technical-Economic Results (US$000s) .................................................................................. 22 Table 6-1: Heap Leach – Historic Actual Production ................................................................................................... 40 Table 6-2: Property History ......................................................................................................................................... 42 Table 6-3: Summary of Quigleys Exploration Database .............................................................................................. 45 Table 7-1: Geologic Codes and Lithologic Units .......................................................................................................... 54 Table 9-1: Exploration Sampling Before 2018 ............................................................................................................ 61 Table 9-2: Exploration Sampling Between 2018 and 2019 by Target Area ................................................................ 62 Table 9-3: Exploration Prospects ................................................................................................................................ 62 Table 10-1: Batman Deposit Drilling History ............................................................................................................... 67 Table 10-2: Batman Deposit Drillholes Added for Resource Update .......................................................................... 68 Table 10-3: Batman Drillhole Details .......................................................................................................................... 69 Table 10-4: Quigleys Deposit Drilling History ............................................................................................................. 99 Table 10-5: Quigleys Drillhole Details ......................................................................................................................... 99 Table 11-1: Assay and Preparation Laboratories ...................................................................................................... 122 Table 11-2: Comparison of Assay Values between the Database and Source Documents (MDA, 2011) ................. 123 Table 11-3: Summary of Comparisons of Historical Assays (MDA, 2011) ................................................................. 124 Table 11-4: Summary of Comparisons of Vista Assays (MDA, 2011) ........................................................................ 125 Table 13-1: Material Balance for HPGR Tests ........................................................................................................... 140 Table 13-2: Tomra Sorting Test Results .................................................................................................................... 142 Table 13-3: Head Analyses of Composite Samples ................................................................................................... 145 Table 13-4: Whole Rock Analyses of Composite Samples ........................................................................................ 145 Table 13-5: Assayed vs. Projected Head Analyses .................................................................................................... 146 Table 13-6: Abrasion Indices for the Various Composite Samples ........................................................................... 146 Table 13-7: Bond Ball Mill Work Indices for Composite Samples ............................................................................. 147 Table 13-8: Bond Ball Mill Work Indices for Ore Sorting Products and Wastes ....................................................... 147

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 xii Table 13-9: Gold Extraction vs. Grind Size for the Four Composites ........................................................................ 148 Table 13-10: Gold Extraction at P80 of 270 mesh (53μm) with Two-stage Grind for the Four Composites ............. 149 Table 13-11: Effect of Pulp Density and NaCN Concentration on Gold Extraction for Composite No. 1 at P80 of 270 mesh (53μm) with Two-stage Grinding ......................................................................................... 150 Table 13-12: Effect of Pulp Density and NaCN Concentration on Gold Extraction for Composite No. 3 at P80 of 270 mesh (53μm) with Two-stage Grinding ......................................................................................... 150 Table 13-13: Effect of Pulp Density and NaCN Concentration on Gold Extraction for Composite No. 4 at P80 of 270 mesh (53μm) with Two-stage Grinding ......................................................................................... 151 Table 13-14: Cyanide Destruction Test Results ........................................................................................................ 151 Table 13-15: Unit Area Requirements for Thickener for Composite Samples .......................................................... 152 Table 13-16: Metallurgical Drilling Intercept Angle to Mineralized Vein ................................................................. 152 Table 13-17: Vista Drillholes and their Metallurgical Twins ..................................................................................... 153 Table 13-18: Material Balance for HPGR Tests at TKI ............................................................................................... 155 Table 13-19: Tomra Ore Sorting Test Results ........................................................................................................... 156 Table 13-20: Steinert Sorting Results for Composites 1, 3 and 4 ............................................................................. 158 Table 13-21: Head Analyses of Composite Samples ...................................................................................... 159 Table 13-22: Bond's Ball Mill Work Indices for Composite Samples ........................................................... 159 Table 13-23: Leach Results for Feed Grade >1.5 g/t Au ........................................................................................... 162 Table 13-24: Leach Results for Feed Grade of 1.0 to 1.5 g/t Au ............................................................................... 162 Table 13-25: Leach Results for Feed Grade of0.8 to 1.0 g/t Au ................................................................................ 163 Table 13-26: Leach Results for Feed Grade of 0.6 to 0.8 g/t Au ............................................................................... 163 Table 13-27: Leach Results for Feed Grade of 0.4 to 0.6 g/t Au ............................................................................... 164 Table 13-28: Leach Results for Feed Grade of <0.4 g/t Au ....................................................................................... 164 Table 13-29: Leach Residue Assay Versus Ore Feed Grade ...................................................................................... 165 Table 13-30: Cyanide Destruction Test Results ............................................................................................... 166 Table 14-1: Summary of the Batman, Heap Leach Pad and Quigleys Deposits ........................................................ 171 Table 14-2: Summary of Batman Bulk Density Data by Oxidation State .................................................................. 175 Table 14-3: Block Model* Physical Parameters – Batman Deposit .......................................................................... 175 Table 14-4: Batman Resource Classification Criteria and Variogram ....................................................................... 178 Table 14-5: Batman Deposit Measured and Indicated Gold Resource Estimate ...................................................... 186 Table 14-6: Batman Deposit Inferred Gold Resource Estimate ................................................................................ 187 Table 14-7: Quigleys Deposit Specific Gravity Data .................................................................................................. 191 Table 14-8: Summary of Quigleys Exploration Database .......................................................................................... 192 Table 14-9: Block Model Physical Parameters – Quigleys Deposit ........................................................................... 192 Table 14-10: Search Parameters for each Domain ................................................................................................... 195 Table 14-11: Search Parameters and Sample Restrictions ....................................................................................... 195 Table 14-12: WhittleTM Pit Shell Parameters for the Quigleys Deposit..................................................................... 196 Table 14-13: Estimated Resources Measured and Indicated Classes for the Quigleys Deposit, All Mineral Types .................................................................................................................................................... 196 Table 14-14: Estimated Resource Inferred Class for the Quigleys Deposit, ............................................................. 198 Table 14-15: Existing Heap Leach Indicated Gold Resource Estimate (September 2019) ........................................ 199 Table 15-1: Initial Economic Parameters ................................................................................................................... 201 Table 15-2: Slope Angles for Pit Optimization .......................................................................................................... 203

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 xiii Table 15-3: WhittleTM Pit Optimization Results –using 0.40 g-Au/t Cutoff ............................................................... 205 Table 15-4: Pit Design Slope Parameters .................................................................................................................. 207 Table 15-5: Interim Pit Slope Parameters (Sectors 1 & 2) ........................................................................................ 207 Table 15-6: US$1,250 Gold Price Cutoff Grades (g-Au/t) ......................................................................................... 214 Table 15-7: In-Pit Proven and Probable Reserves by Pit Phase ................................................................................ 216 Table 15-8: Total Batman Project Reserves (Including Heap Leach) ........................................................................ 216 Table 16-1: Description of Landforms and Impoundments ...................................................................................... 218 Table 16-2: Construction and Reclamation Requirements ....................................................................................... 220 Table 16-3: Annual Mine Production Schedule ........................................................................................................ 223 Table 16-4: Annual Stockpile Balance ....................................................................................................................... 224 Table 16-5: Annual Ore Delivery to the Mill Crusher ................................................................................................ 225 Table 16-6: Maximum Loader Productivity Estimate ............................................................................................... 227 Table 16-7: Annual Load and Haul Equipment Requirements .................................................................................. 229 Table 16-8: Mine Personnel Requirements .............................................................................................................. 232 Table 17-1: Headline Design Criteria ......................................................................................................................... 234 Table 17-2: Mobile Equipment for Process Plant ..................................................................................................... 243 Table 18-1: 50 ktpd TSF 1 and TSF 2 Parameters ...................................................................................................... 250 Table 18-2: Mobile Equipment for Process Plant ..................................................................................................... 251 Table 18-3: Heavy Lift Cranage Requirements ......................................................................................................... 255 Table 18-4: Power Station Location Budgetary Comparison .................................................................................... 261 Table 20-1: Mt Todd Permit Status ........................................................................................................................... 271 Table 20-2: Reclamation Approach ........................................................................................................................... 272 Table 21-1: Operating Periods .................................................................................................................................. 277 Table 21-2: Estimated Capital Cost Summary (US$000s) ......................................................................................... 278 Table 21-3: Estimated Mine Annual Capital Costs (US$000s) ................................................................................... 279 Table 21-4: Estimated Mine Light Vehicle Capital (US$ ) .......................................................................................... 283 Table 21-5: Estimated Capital Cost Summary (AUD000s)......................................................................................... 284 Table 21-6: CCE Methodology for Facility 3000 – Process Plant .............................................................................. 285 Table 21-7: Methodology for Other Areas of the Capital Cost Estimate .................................................................. 286 Table 21-8: Estimated Construction Gang Rate Development (AUD)....................................................................... 289 Table 21-9: Estimated Power Station Installed Capital Cost Summary (AUD) .......................................................... 293 Table 21-10: Estimated Mine Dewatering Capital Cost Summary (US$000s) ........................................................... 294 Table 21-11: Estimated Reclamation Capital Cost Summary (US$000s) .................................................................. 294 Table 21-12: Estimated Water Treatment Plant Capital Cost Summary (US$000s) ................................................. 295 Table 21-13: Estimated Raw Water Dam Capital Cost Summary (US$000s) ............................................................ 295 Table 21-14: Estimated Tailings Storage Facility Capital Cost Summary (US$000s) ................................................. 296 Table 21-15: Estimated LoM Operating Costs (US$) ................................................................................................. 297 Table 21-16: Estimated Annual Mine Operating Costs (US$) ................................................................................... 300 Table 21-17: Estimated Plant Operating Costs (@ Steady State) (AUD) ................................................................... 301 Table 21-18: Estimated Fuel Cost Summary (AUD) .................................................................................................. 306 Table 21-19: Estimated Personnel Costs, Power Plant (AUD) .................................................................................. 307 Table 21-20: Estimated Gas Turbine Maintenance Cost Schedule – 70MW (AUD) .................................................. 308

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 xiv Table 22-1: TEM Principal Assumptions ................................................................................................................... 309 Table 22-2: Estimated Refining Costs (US$) .............................................................................................................. 310 Table 22-3: LoM Ore Production .............................................................................................................................. 310 Table 22-4: Estimated LoM Capital Costs (US$000s) ................................................................................................ 312 Table 22-5: Estimated Mining Costs (US$000s) ........................................................................................................ 313 Table 22-6: Estimated CIP Process Plant Capital Costs (US$000s) ............................................................................ 313 Table 22-7: Estimated Project Services Capital Costs (US$000s) .............................................................................. 314 Table 22-8: Estimated Project Infrastructure Capital Costs (US$000s) .................................................................... 315 Table 22-9: Estimated Permanent Accommodation Costs (US$000s) ...................................................................... 315 Table 22-10: Estimated Site Establishment & Early Works (US$000s) ..................................................................... 316 Table 22-11: Estimated Management, Engineering, EPCM Services (US$000s) ....................................................... 316 Table 22-12: Estimated Pre-Production Costs (US$000s) ......................................................................................... 317 Table 22-13: Estimated Asset Sale (US$000s) ........................................................................................................... 317 Table 22-14: Estimated LoM Operating Costs (US$) ................................................................................................. 318 Table 22-15: Estimated Open Pit Operating Costs (US$) .......................................................................................... 319 Table 22-16: Estimated CIP Process Plant Operating Costs (US$) ............................................................................ 320 Table 22-17: Estimated Water Treatment Plant Operating Costs (US$) .................................................................. 320 Table 22-18: Estimated Tailings Operating Costs (US$) ............................................................................................ 321 Table 22-19: Estimated G&A Operating Costs (US$) ................................................................................................ 321 Table 22-20: Estimated JAAC Royalty Costs (US$) .................................................................................................... 322 Table 22-21: Estimated Refining Costs (US$) ............................................................................................................ 322 Table 22-22: Estimated Labor Rates & Costs (AUD) ................................................................................................. 323 Table 22-23: Position & Salary Matrix (AUD) ............................................................................................................ 331 Table 22-24: Process Reagents (AUD)....................................................................................................................... 335 Table 22-25: Process Consumables (AUD) ................................................................................................................ 335 Table 22-26: Technical-Economic Results (US$000s) ............................................................................................... 336 Table 22-27: All-In Sustaining Costs (US$/oz) ........................................................................................................... 337 Table 22-28: Annual Cash Flow ................................................................................................................................. 339 Table 22-29: Project Sensitivity ................................................................................................................................ 342 Table 22-30: Sensitivities to Gold Price versus NPV Discount Rate .......................................................................... 343 Table 22-31: Sensitivities to Gold Price versus Foreign Exchange Rate (US$:AUD) .................................................. 343 Table 24-1: Mean Monthly Precipitation .................................................................................................................. 348 Table 24-2: Site-specific Trigger Values, Edith River Downstream of WTP Discharge .............................................. 350 Table 24-3: Edith River Flow at SW4 (m3/h), February 2013 – September 2017 ..................................................... 351 Table 24-4: Water Quality Data at Sampling Site SW2, Edith River Upstream of WTP Discharge, January 2015 – April 2017 .......................................................................................................................................... 352 Table 24-5: Mt Todd WTP Effluent Goals ................................................................................................................. 352 Table 24-6: Anticipated Influent Water Quality at the WTP ..................................................................................... 353 Table 24-7: Opinion of Probable Capital Costs ......................................................................................................... 354 Table 24-8: Opinion of Probable Annual Chemical Consumption ............................................................................ 355 Table 24-9: Catchment and Pit Areas, Inflow Volumes, and Dewatering Times for Mine Dewatering Design ........ 361 Table 24-10: Construction Packages ......................................................................................................................... 371

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 xv Table 24-11: Supply Packages ................................................................................................................................... 372 Table 24-12: Supply Packages with Significant Lead Times ...................................................................................... 381 Table 25-1: Project Risks ........................................................................................................................................... 384 LIST OF FIGURES Figure 1-1: General Project Location Map .................................................................................................................... 4 Figure 1-2: Concessions ................................................................................................................................................ 6 Figure 1-3: General Arrangement ................................................................................................................................. 7 Figure 1-4: Measured & Indicated Resource Estimates Grade Tonnage Curves – Batman Deposit ........................... 10 Figure 1-5: Mt Todd Flowsheet ................................................................................................................................... 14 Figure 4-1: General Project Location Map .................................................................................................................. 35 Figure 4-2: Concessions .............................................................................................................................................. 36 Figure 4-3: General Arrangement ............................................................................................................................... 37 Figure 6-1: Drillhole Location Map – Batman and Quigleys Deposits ......................................................................... 46 Figure 6-2: Plant Process Flowsheet for Project as Designed ..................................................................................... 50 Figure 6-3: Modified Plant Process Flowsheet for Project ......................................................................................... 51 Figure 7-1: General Geologic Map .............................................................................................................................. 56 Figure 7-2: Concessions .............................................................................................................................................. 59 Figure 10-1: Drillhole Location Map Batman Deposit to VB18-003 ............................................................................ 93 Figure 10-2: Batman Cross-section 1 .......................................................................................................................... 94 Figure 10-3: Batman Cross-section 2 .......................................................................................................................... 95 Figure 10-4: Batman Cross-section 3 .......................................................................................................................... 96 Figure 10-5: Batman Cross-section 4 .......................................................................................................................... 97 Figure 10-6: Batman Cross-section 5 .......................................................................................................................... 98 Figure 10-7: Isometric View of the Quigleys Drilling Pattern ................................................................................... 117 Figure 10-8: Quigleys Cross-section A-A’ (8,438,200 North +/- 10m window) ......................................................... 118 Figure 11-1: NAL Pulp Repeats ................................................................................................................................. 126 Figure 11-2: Original Pulp Cross Lab Checks ............................................................................................................. 127 Figure 12-1: NAL Resplit Analyses ............................................................................................................................. 131 Figure 12-2: Scatterplot of Relative Au Value to Certified Standard Reference Material Value .............................. 133 Figure 12-3: Scatterplots (Log Scale) of Replicates by Drillhole ................................................................................ 134 Figure 12-4: Location of Metallurgical Drillholes ...................................................................................................... 135 Figure 12-5: Two Views of VB07-013, VB18-002 and VB08-036 in Cross-sections ................................................... 136 Figure 13-1: Protocol for HPGR/Ore Sorting ............................................................................................................. 140 Figure 13-2: Drillhole Trace of VB08-030, VB17-001 and VB08-012 ......................................................................... 153 Figure 13-3: Drill hole trace of drillholes VB08-030, VB17-001 and VB08-012 ......................................................... 154 Figure 13-4: Conceptual Process Flowsheet for Mt Todd Ore (1/2) ......................................................................... 167 Figure 13-5: Conceptual Process Flowsheet for Mt Todd Ore (2/2) ......................................................................... 168 Figure 14-1: Drillhole Location Map Batman & Quigleys Deposits and Heap Leach Pad ......................................... 170 Figure 14-2: Schematic of Codes and Surface Designations (Looking North) ........................................................... 173

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 xvi Figure 14-3: Sectional View of Drillhole Data 8,434,803 mN (Looking North) ......................................................... 174 Figure 14-4: Example Log Variograms of Gold within the Core Complex ................................................................. 177 Figure 14-5: Blocks Kriged Au – Cross-section 8,434,900 mN Looking North, Batman Deposit .............................. 180 Figure 14-6: Classified Blocks Measured, Indicated, and Inferred – Cross-section 8,434,900 mN Looking North, Batman Deposit .................................................................................................................................... 181 Figure 14-7: Blocks Kriged Au – Level Plan -100m msl Batman Deposit .................................................................... 182 Figure 14-8: Classified Blocks Measured, Indicated, and Inferred – Level Plan -100m msl Batman Deposit ........... 183 Figure 14-9: Blocks Kriged Au – Long Section of the Core Complex Looking West .................................................. 184 Figure 14-10: Classified Blocks Measured, Indicated, and Inferred – Long Section of the Core Complex Looking West ........................................................................................................................................ 185 Figure 14-11: Grade Tonnage Curve of Measured and Indicated Resource for the Batman Deposit ...................... 187 Figure 14-12: Jackknife Correlation Plot for Measured Blocks ................................................................................. 189 Figure 14-13: Jackknife Correlation Plot for Inferred Blocks .................................................................................... 190 Figure 14-14: 3-D Visualization of the Quigleys Deposit Mineralized Zone Positions with Wireframe Codes ........ 193 Figure 14-15: Quigleys Median Indicator Variogram ................................................................................................ 194 Figure 14-16: Grade Tonnage Curve Estimated Resources Measured and Indicated Class, All Mineral Types for the Quigleys Deposit ....................................................................................................................... 197 Figure 14-17: Inferred Resource Grade Tonnage Curve for the Quigleys Deposit ................................................... 199 Figure 15-1: Mt Todd Geotechnical Sectors ............................................................................................................. 204 Figure 15-2: Measured and Indicated Graph of WhittleTM Results –0.40 g-Au/t Minimum Grade .......................... 206 Figure 15-3: Mt Todd Ultimate Pit Design – (October 4, 2019) ................................................................................ 209 Figure 15-4: Phase 1 Design (February 12, 2018) ..................................................................................................... 211 Figure 15-5: Phase 2 Design (February 12, 2018) ..................................................................................................... 212 Figure 15-6: Phase 3 Design (February 12, 2018) ..................................................................................................... 213 Figure 16-1: Mine Organizational Chart ................................................................................................................... 231 Figure 17-1: Simplified Process Flow Diagram .......................................................................................................... 236 Figure 18-1: Power Station Location ......................................................................................................................... 260 Figure 18-2: Conceptual Electrical Line Diagram ...................................................................................................... 263 Figure 18-3: General Plant Arrangement .................................................................................................................. 264 Figure 22-1: Project Sensitivity ................................................................................................................................. 342 Figure 24-1: Open Pit Dewatering System Conceptual Design ................................................................................. 363 Figure 24-2: Conceptual Layout of Dewatering System............................................................................................ 364 Figure 24-3: EPCM Stage 1 – Design & Procurement. Refer Diagram 1 ................................................................... 366 Figure 24-4: EPCM Stage 2 – Construct & Commission. Refer Diagram 2 ................................................................ 367 Figure 24-5: Commissioning Phases ......................................................................................................................... 377 Figure 24-6: EPCM Summary Schedule ..................................................................................................................... 383

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 xvii ACRONYMS, ABBREVIATIONS AND SYMBOLS " second (plane angle) % percent ‘ minute (plane angle) < less than > greater than ° degree °C degrees Celsius °F degrees Fahrenheit μg micrograms μg/L micrograms per liter or parts per billion μm microns μS/cm microsiemens per centimeter 3D three-dimensional A ampere a annum (year) ABA acid base accounting AD annual deduction ADWG Australian Drinking Water Guidelines AGR Australian Gold Reagents Pty. Ltd. ALS Australian Laboratory Services AN Ammonium nitrate ANE Ammonium nitrate emulsion ANFO Ammonium nitrate fuel oil ANZECC Australian and New Zealand Environment Conservation Council ANZMARC Australian and New Zealand Marketing Academy AOM Australian Ores and Minerals Limited AP aeration/settling ponds APW Aerobic Polishing Wetlands ARD/ML acid rock drainage and metal laden leachates ARMCANZ Agriculture and Resource Management Council of Australia and New Zealand AStrk Along Strike Au gold AUD dollar (Australian) Ausenco Ausenco Limited B billion BCR biochemical reactor

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 xviii BFA Bench face angle bgs below ground surface BH Bench height BKK Bateman Kinhill and Kilborne BP Batman pit Bt billion tonnes BWi Bond Ball Mill work index CAPEX capital expenditure or capital expense CCE Capital Cost Estimate CCI Chamber of Commerce and Industry CCTV closed circuit television CDN Canadian dollar CIL carbon-in-leach CIM Canadian Institute of Mining, Metallurgy and Petroleum CIM Standards Canadian Institute of Mining, Metallurgy and Petroleum Definition Standards CIP carbon-in-pulp cm centimeters cm2 square centimeter cm3 cubic centimeter CoA chart of accounts CRD capital recognition deduction CV Construction Verification CWi Crusher work index d day d/a days per year (annum) D&C Design and Construct d/wk days per week DDH Diamond drillhole core DH drillhole dmt dry metric ton DO Dissolved oxygen DoR Department of Resources DRDPIFR Department of Regional Development, Primary Industry, Fisheries and Resources DC Dry Commissioning DUST dust suppression DWi Drop Weight index E&I Electrical and Instrumentation EEE eligible exploration expenditure EFCE Enhanced Factored Cost Estimate

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 xix EHS Environment, Health and Safety EIS Environmental Impact Statement EL exploration licenses EMP Environmental Management Plan EPBC Australian Environmental Protection and Biodiversity Conservation Act of 1999 EPCM Engineering procurement construction management EQP equalization pond F80 80% feed passing size FIS Free In Store FLS FLSmidth FS Feasibility Study ft foot ft2 square foot ft3 cubic foot ft3/s cubic feet per second g gram g/L grams per liter g/m3 gram per cubic meter g Au/t grams gold per tonne g/t grams per tonne G&A general and administrative Ga billion years ago GCL geosynthetic clay liner General Gold General Gold Resources Pty. Ltd. GHD GHD Pty Ltd. GJ Gigajoule gpm gallons per minute (US) GR gross realization GW gigawatt h/a hours per year h/d hours per day h/wk hours per week ha hectare (10,000 m2) HAZOP Hazard and Operability HCL Hydrochloric Acid HHV Higher Heating Value HLP heap leach pad HNO3 nitric acid HPGR high pressure grinding rolls

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 xx HQ 88.9 mm drill rod (outer diameter) hr hour HSEC Health, Safety, Environment and Community HV Heavy vehicles HW hanging wall Hz hertz IBC Intermediate bulk containers ICP Inductively Coupled Plasma Atomic Emission Spectroscopy ICP-OES Inductively Coupled Plasma Optical Emission Spectroscopy in inch in2 square inch in3 cubic inch IP Internet Protocol IRA Inner-ramp angles IRR Internal Rate of Return IR Industrial Relations IT Information Technology ITV interim trigger values JAAC Jawoyn Association Aboriginal Corporation k kilo (thousand) kg kilogram kg/h kilograms per hour kg/m2 kilograms per square meter kg/m3 kilograms per cubic meter km kilometer km/h kilometers per hour km2 square kilometer koz kilo-ounce kPa kilopascal kt kilotonne KV Kriging variance kV kilovolts kVA kilovolt-ampere kW kilowatt kWh kilowatt hour kWh/a kilowatt hours per year kWh/t kilowatt hours per tonne kW/sec Kilowatts per second L liter

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 xxi L/m liters per minute lb pound(s) LGOS low grade ore stockpile LIMS Laboratory information system LLDPE linear low-density polyethylene LoM life of mine LPM low-permeability material m meter(s) M million m bgs meters below ground surface m/min meters per minute m/s meters per second m2 square meter m3 cubic meter m3/hr cubic meter(s) per hour MARC maintenance and repair contract masl meters above mean sea level Mb/s megabytes per second Mbm3 million bank cubic meters Mbm3/a million bank cubic meters per annum mbsl meters below sea level MCC Motor Control Center MDA Mine Development Associates μg/L micrograms per liter MGA Map Grid of Australia mg milligram mg/L milligrams per liter or parts per million mg/L milligrams per liter MIF Measured, Indicated, inferred min minute (time) mL milliliter MLN Mineral License Number mm millimeter MMP Mining Management Plan mo month Moz million ounces Mpa megapascal mPaͼs centipoise MPU Mobile processing unit

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 xxii MRT Mining & Resource Technology Pty Ltd Mt million tonnes Mt/a million tonnes per annum MTO material take-off Mtpy million tonnes per year MVA megavolt-ampere MW megawatt MWH Montgomery Watson Harza (now Stantec) N/mm2 Newtons per square millimeter NAG Net Acid Generation NAL Northern Australian Laboratories NaOH sodium hydroxide NaSH sodium hydrosulfide NAPP net acid production potential NHMRC National Health and Medical Research Council NI National Instrument Nm3/h Normal meters cubed per hour NOI Notice of Intent NP neutralization potential NPI Non Process Infrastructure NPR neutralizing potential ratio NPV Net Present Value NQ 69.9 mm drill rod (outer diameter) NRETAS Natural Resources, Environment, the Arts and Sport NRMMC Natural Resource Management Ministerial Council NSR Net Smelter Return NT Northern Territory NTEL NT Environmental Laboratories NTEPA Northern Territory Environmental Protection Authority ø diameter OC operating costs OH&S Occupational Health and Safety OP open rotary holes OPEX operating expenditure or operating expense OPGW optical ground wire oz ounce oz/a ounces/annum oz/d ounces/day P80 80% product passing size, in microns or μm

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 xxiii P&ID piping and instrumentation diagram Pa Pascal Pacific Gold Mines Pacific Gold Mines NL PAG potentially acid generating PAH Pincock Allen and Holt PbS galena PC Prime Cost PCG Pine Creek Geosyncline pcg Porphyry copper gold PER Public Environmental Report PFS Preliminary Feasibility Study PGM plant growth medium POWER POWER Engineers, Inc. PP Process Plant ppb parts per billion ppm parts per million Project Mt Todd Gold Project PRP Process Plant Retention Pond PWC Power and Water Corporation PWP Process Water Pond QA/QP Quality Assurance/Quality Control QP Qualified Person R&R Rest and recreation RDi Resource Development Inc. RKD RKD (Company Name) RL Sample name RO runoff pond RoM Run of Mine RP retention pond rpm revolutions per minute RVC reverse circulation drilling method RWD raw water dam s second (time) SAPS Successive alkalinity producing systems SG specific gravity SMBS sodium metabisulfite SMC SAG mill comminution SME Society for Mining, Metallurgy, and Exploration, Inc. SMP Structural, Mechanical and Piping

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 xxiv SOCS Site of Conservation Significance SoW Scope of Work SPX SPX company name SRE Soil and Rock Engineering st short ton (2,000 lb) st/d short tons per day st/y short tons per year S.U. Standard unit SWWB Site-wide water balance t tonne (1,000 kg) (metric ton) t/a tonnes per year t/d tonnes per day t/m3 tonnes per cubic meter Technical Report this Preliminary Feasibility Study TEM technical economic model Tetra Tech Tetra Tech, Inc. TKI Thyssen-Krupp Industries tpd tonnes per day tph tonnes per hour TSF tailings storage facility TTP Coffey Services Australia Pty Ltd (trading as Tetra Tech Proteus) TUNRA The University of Newcastle Research Associates TV Trigger value TWC The Winters Company UCS Unconfined compressive strength US$ U.S. dollar V volt Vista Vista Gold Corp. Vista Australia Vista Gold Australia Pty Ltd VoIP voice over Internet protocol w/v weight/volume w/w weight/weight WA Western Australia WAD weak acid dissociable WC Wet Commissioning WDL Waste Discharge License WGC World Gold Counsel wk week WRD waste rock dump

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 xxv WTP water treatment plant WWTP waste water treatment plant XRD x-ray diffraction yd3 cubic yard ZnS Sphalerite

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 xxvi UNITS OF MEASURE All dollars are presented in U.S. dollars (US$) unless otherwise noted. Common units of measure and conversion factors used in this report include: Weight: 1 oz (troy) = 31.1035 g Analytical Values: percent grams per metric tonne 1% 1% 10,000 1 g/t 0.0001% 1.0 10 ppb 100 ppm Linear Measure: 1 inch (in) = 2.54 centimeters (cm) 1 foot (ft) = 0.3048 meters (m) 1 yard (yd) = 0.9144 meters (m) 1 mile (mi) = 1.6093 kilometers (km) Area Measure: 1 acre = 0.4047 hectare 1 square mile = 640 acres = 259 hectares

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 xxvii ABBREVIATIONS OF THE PERIODIC TABLE actinium = Ac aluminum = Al americium = Am antimony = Sb argon = Ar arsenic = As astatine = At barium = Ba berkelium = Bk beryllium = Be bismuth = Bi bohrium = Bh boron = B bromine = Br cadmium = Cd calcium = Ca californium = Cf carbon = C cerium = Ce cesium = Cs chlorine = Cl chromium = Cr cobalt = Co copper = Cu curium = Cm dubnium = Db dysprosium = Dy einsteinium = Es erbium = Er europium = Eu fermium = Fm fluorine = F francium = Fr gadolinium = Gd gallium = Ga germanium = Ge gold = Au hafnium = Hf hassium = Hs helium = He holmium = Ho hydrogen = H indium = In iodine = I iridium = Ir iron = Fe joliotium = Jl krypton = Kr lanthanum = La lawrencium = Lr lead = Pb lithium = Li lutetium = Lu magnesium = Mg manganese = Mn meitnerium = Mt mendelevium = Md mercury = Hg molybdenum = Mo neodymium = Nd neon = Ne neptunium = Np nickel = Ni niobium = Nb nitrogen = N nobelium = No osmium = Os oxygen = O palladium = Pd phosphorus = P platinum = Pt plutonium = Pu polonium = Po potassium = K praseodymium = Pr promethium = Pm protactinium = Pa radium = Ra radon = Rn rhodium = Rh rubidium = Rb ruthenium = Ru rutherfordium = Rf rhenium = Re samarium = Sm scandium = Sc selenium = Se silicon = Si silver = Ag sodium = Na strontium = Sr sulfur = S technetium = Tc tantalum = Ta tellurium = Te terbium = Tb thallium = Tl thorium = Th thulium = Tm tin = Sn titanium = Ti tungsten = W uranium = U vanadium = V xenon = Xe ytterbium = Yb yttrium = Y zinc = Zn zirconium = Zr

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 1 1.0 SUMMARY 1.1 Introduction Vista Gold Corp. (Vista) retained Tetra Tech, Inc., along with JDS Energy & Mining, Inc. (JDS), Mine Development Associates (MDA), Resource Development Inc. (RDi), Tetra Tech Proteus (TTP), and POWER Engineers, Inc. (POWER) to prepare this preliminary feasibility study (PFS) for its Mt Todd Gold Project (the Project) in Northern Territory (NT), Australia. The PFS (Technical Report) evaluates a development scenario of a 50,000 tonne per day (tpd) processing facility. Vista and its subsidiary, Vista Gold Australia Pty Ltd (Vista Australia) entered into an agreement to acquire an interest in the Project located in NT, Australia on March 1, 2006. The acquisition was completed on June 16, 2006 when the mineral leases comprising the Project were transferred to Vista Australia and funds held in escrow were released. Vista Australia is the operator of the Mt Todd property. The Mt Todd property contains a number of known occurrences of gold, which have been explored and/or exploited to various degrees. The largest and best-known deposits are the Batman and Quigleys deposits, both of which have had historic mining by prior operators. The Batman deposit has produced and been explored more extensively than the Quigley deposit. Vista has reported mineral resource estimates in accordance with National Instrument (NI) 43-101 Standards of Disclosure for Mineral Projects and Canadian Institute of Mining, Metallurgy and Petroleum Definition Standards (CIM) for Mineral Resources and Mineral Reserves (CIM Standards) for the Batman and Quigley deposits and a mineral reserve estimate in accordance with NI 43-101 and CIM Standards for only the Batman deposit. The Technical Report provides updated material, scientific, and technical information based on additional data obtained from extensive metallurgic test work conducted in 2018 and 2019. The recent metallurgic test programs have confirmed: (1) the efficiency of ore sorting across a broad range of head grades and the natural concentration of gold in the screen undersize material prior to sorting; (2) the efficiency of fine grinding and improved gold leach recoveries at an 80% passing grind size of 40 microns; and (3) the selection of FLSmidth’s (FLS) VXP mill as the preferred fine grinding mill. In September, 2020, the Technical Report was amended to correct and/or clarify certain items, including: „ Changes to the title page to include each Qualified Person’s (QP) professional designation to comply with form requirements „ Clarification of QP disclaimers and additions to Section 3 – Reliance on Other Experts to comply with form requirements „ Additions to Section 9 - Exploration and Section 10 - Drilling to comply with form requirements „ Clarification of credentials in certificates for specific QPs „ Adjustment of measured, indicated, and inferred mineral resources for Quigleys deposit „ Certain other minor changes to comply with form requirements There are no changes to the following key items in the Technical Report: „ Reported measured, indicated, and inferred mineral resources for Batman deposit „ Reported design parameters for the open pit mine plans „ Reported proven and probable mineral reserves

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 2 „ Reported design parameters for the process plant or process flow sheet „ Reported metallurgical recoveries and associated supporting test work „ Reported capital and operating costs „ Reported design parameters for the tailings dams and waste rock dump „ Reported design parameters and associated costs for the reclamation plan „ Reported financial results from the cash flow analysis, rates of return, and schedules This information is intended to assist stakeholders and other readers of this Technical Report in their understanding of the Mt Todd Gold Project and in forming judgements regarding the quality of the data collected, reported, and used in the Technical Report. The highlights of the PFS are presented in Table 1-1. Table 1-1: PFS Highlights Description Years 1-5 Life of Mine (LoM) (13 years) Annual Average Total Annual Average Total Average Plant Feed Grade (g-Au/t) 0.96 0.82 Payable Gold (koz) 495 2,476 413 5,305 Gold Recovery (%) 92.3% 91.9% Cash Costs (US$/oz) $575 $645 AISC ($/oz) $688 $746 Strip Ratio (waste:ore) 2.65 2.52 Initial Capital (US$ millions) $826 After-tax Payback (Production Years) 2.9 After-tax NPV5% (US$ millions) $823 IRR (Pre-tax / After-tax) (%) 23.4% NOTE: Economics presented using US$1,350/oz gold and a flat US$0.70:AUD1.00 exchange rate and assumes deferral of NT Royalty payments prior to payback, and sale of excess electric power during reclamation and realization of salvage values at the end of the mine life. 1.2 Location The Project is located 56 kilometers (km) by road northwest of Katherine, and approximately 290 km southeast of Darwin in NT, Australia (Figure 1-1). Access to the property is via high quality, two-lane paved roads from the Stuart Highway, the main arterial within the territory.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 3 1.3 Property Description Vista Australia is the holder of four mineral licenses (ML) MLN 1070, MLN 1071, MLN 1127, and MLN 31525 comprising approximately 5,544 hectares (ha). In addition, Vista Australia controls exploration licenses (EL) EL 29882, EL 29886, EL 30898, and EL 28321 comprising approximately 153,700 ha. Figure 1-1 illustrates the general location of the tenements and the position of the Batman deposit. The general arrangement for the Project is shown on Figure 1-3, and landforms and impoundments are described in Table 1-2.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 4 Figure 1-1: General Project Location Map

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 5 Table 1-2: Description of Landforms and Impoundments Landform/Impoundment Abbreviated Name Tailings Storage Facility 1 TSF 1 Tailings Storage Facility 2 TSF 2 Raw Water Dam RWD Low Grade Ore Stockpile LGOS Low Grade Ore Stockpile Retention Pond LGRP Heap Leach Pad HLP Batman Pit RP3 Process Plant Retention Pond PRP Waste Rock Dump WRD Waste Rock Dump Retention Pond RP1 Process Water Pond PWP Water Treatment Plant WTP Process Plant PP

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 6 NOTE: Prepared by Vista Gold Corp.; updated on February 23, 2018 Figure 1-2: Concessions

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 7 Figure 1-3: General Arrangement

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 8 1.4 Geology and Mineralization The Project is situated within the southeastern portion of the Early Proterozoic Pine Creek Geosyncline (PCG). Meta-sediments, granitoids, basic intrusives, acid and intermediate volcanic rocks occur within this geological province. The Batman deposit geology consists of a sequence of hornfelsed interbedded greywackes, and shales with minor thin beds of felsic tuff. Bedding is striking consistently at 325°, dipping at 40° to 60° to the southwest. Minor lamprophyre dykes trending north-south pinch and swell, crosscutting the bedding. The deposits are similar to other gold deposits of the PCG and are classified as orogenic gold deposits in the subdivision of thermal aureole gold style. The Batman deposit shares some characteristics with intrusion- related gold systems, especially in terms of the association of gold with bismuth and reduced ore mineralogies. This makes the Batman deposit unique in the PCG. The mineralization within the Batman deposit is directly related to the intensity of the north-south trending quartz sulfide veining. The lithological units impact on the orientation and intensity of mineralization. Sulfide minerals associated with the gold mineralization are pyrite, pyrrhotite and lesser amounts of chalcopyrite, bismuthinite and arsenopyrite. Galena and sphalerite are also present but appear to be post- gold mineralization and are related to calcite veining, bedding and the east-west trending faults and joints. A variety of mineralization styles occur within the Project area. Of greatest known economic significance are auriferous quartz-sulfide vein systems. These vein systems include the Batman, Jones, Golf, Quigleys and Horseshoe prospects, which occur within a north-northeast trending corridor, and are hosted by the Burrell Creek Formation. Tin occurs in a north-northwest trending corridor. The tin mineralization comprises cassiterite, quartz, tourmaline, kaolin, and hematite bearing assemblages, which occur as bedding parallel to breccia zones and pipes. Polymetallic Au, W, Mo, and Cu mineralization occurs in quartz-greisen veins within the Yinberrie Leucogranite; a late stage highly fractionated phase of the Cullen Batholith. The Batman deposit extends approximately 2,200 meters (m) along strike, 400 m across dip and drill tested to a depth of 800 m. Drilling indicates the Batman mineralization to be open along-strike and down-dip. To date, with regard to the exploration licenses (ELs), they represent an early-stage exploration program which has not produced an announceable discovery. While the work is promising and will be ongoing, there are no quantifiable resources or reserves on the ELs. Once an announceable discovery is made, Vista will detail that discovery according to all applicable disclosure regulations. 1.5 Mineral Resource Estimate The following sections summarize the process, procedures, and results of Tetra Tech’s independent estimate of the contained gold resources of the: 1) Batman deposit; 2) Existing heap leach pad; and 3) Quigleys deposit. The resource estimate for the Batman deposit is updated from the NI 43-101 Technical Report – Mt Todd Gold Project, 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia, Amended & Restated; July 7, 2014 prepared by Tetra Tech. This report includes an estimate of gold contained in a historic heap leach pad adjacent to the Batman deposit. Additionally, this report contains the resource estimation of the

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 9 Quigleys deposit. The updated Project resource estimates are shown in Table 1-3, grade tonnage curve for the measured and indicated resource for the Batman deposit is presented in Figure 1-4. Table 1-3: Statement of Mineral Resources Estimates Batman Deposit Heap Leach Pad Quigleys Deposit Tonnes (000s) Grade (g/t) Containe d Ounces (000s) Tonnes (000s) Grade (g/t) Containe d Ounces (000s) Tonnes (000s) Grade (g/t) Containe d Ounces (000s) Measured (M) 77,725 0.88 2,191 - - - 594 1.15 22 Indicated (I) 200,112 0.80 5,169 13,354 0.54 232 7,301 1.11 260 Measured & Indicated 277,837 0.82 7,360 13,354 0.54 232 7,895 1.11 282 inferred (F) 61,323 0.72 1,421 - - - 3,981 1.46 187 NOTES: (1) Measured & indicated resources include proven and probable reserves. (2) Batman and Quigleys resources are quoted at a 0.40g-Au/t cut-off grade. Heap Leach resources are the average grade of the heap, no cut-off applied. (3) Batman: Resources constrained within a US$1,300/oz gold WhittleTM pit shell. Pit parameters: Mining Cost US$1.50/tonne, Milling Cost US$7.80/tonne processed, G&A Cost US$0.46/tonne processed, G&A/Year 8,201 K US4, Au Recovery, Sulfide 85%, Transition 80%, Oxide 80%, 0.2g-Au/t minimum for resource shell. Selling Cost: US$/oz recovered US412.00. (4) Quigleys: Resources constrained within a US$1,300/oz gold WhittleTM pit shell. Pit parameters: Mining cost US$1.90/tonne, Processing Cost US$9.779/tonne processed, Sale Cost US$/oz US$3.19, Royalty 1% NPR, Gold Recovery Sulfide, 82.0% and Ox/Trans 78.0%, water treatment US $ 0.09/tonne, Tailings $US 0.985/tonne (5) Differences in the table due to rounding are not considered material. Differences between Batman and Quigleys mining and metallurgical parameters are due to their individual geologic and engineering characteristics. (6) Rex Bryan of Tetra Tech is the QP responsible for the Statement of Mineral Resources for the Batman, Heap Leach Pad and Quigleys deposits. (7) Thomas Dyer of Mine Development Associates is the QP responsible for developing the resource WhittleTM pit shell for the Batman Deposit. (8) The effective date of the Heap Leach, Batman and Quigleys resource estimate is September 2019. (9) Mineral resources that are not mineral reserves have no demonstrated economic viability and do not meet all relevant modifying factors.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 10 Source: Tetra Tech, Inc (August 2019). NOTE: Mineral resources that are not mineral reserves have no demonstrated economic viability and do not meet all relevant modifying factors. Figure 1-4: Measured & Indicated Resource Estimates Grade Tonnage Curves – Batman Deposit 1.6 Mineral Reserve Estimates The QP [Thomas L. Dyer, P.E.] has used measured and indicated resources provided by Tetra Tech to estimate mineral reserves. Pit optimization was done using Geovia’s WhittleTM software to define pit limits with input for economic and slope parameters. Optimization used only measured and indicated resources for processing. All inferred resource was considered as waste. Varying gold prices were used to evaluate the sensitivity of the deposit to the price of gold as well as to develop a strategy for optimizing Project cash flow. To achieve cash-flow optimization, mining phases or push backs were developed using the guidance of WhittleTM pit shells at lower gold prices.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 11 The statement of mineral reserve estimates is shown in Table 1-4. Table 1-4: Statement of Mineral Reserve Estimate Batman Deposit Heap Leach Pad Total P&P Reserves Tonnes (000s) Grade (g/t) Containe d Ounces (000s) Tonnes (000s) Grade (g/t) Containe d Ounces (000s) Tonnes (000s) Grade (g/t) Contained Ounces (000s) Proven 72,672 0.88 2,057 - - - 72,672 0.88 2,057 Probable 135,015 0.82 3,559 13,354 0.54 232 148,369 0.79 3,791 Proven & Probable 207,687 0.84 5,616 13,354 0.54 232 221,041 0.82 5,848 NOTES: (1) Thomas L. Dyer, P.E., is the QP responsible for reporting the Batman deposit proven and probable reserves. (2) Batman deposit reserves are reported using a 0.40 g-Au/t cutoff grade. (3) Deepak Malhotra is the QP responsible for reporting the heap-leach pad reserves. (4) Because all of the heap-leach pad reserves are to be fed through the mill, these reserves are reported without a cutoff grade applied. (5) The reserves point of reference is the point where material is fed into the mill. (6) The effective date of the mineral reserve estimates is September 2019. 1.6.1 Heap Leach Reserve Estimate Existing heap leach pad (HLP) reserves are provided in Table 1-4, which are estimated to be 13.4 million tonnes (Mt). These reserves will be processed through the mill at the end of the mine life. Previous test work indicated the following possible results: „ Cyanidation leach tests on “as is” material on the heap will extract ± 30% of the gold. „ CIP cyanidation tests at a grind size of P80 of 90 microns will extract on average 72% of gold (range: 64.14% to 80.37%) in 24 hours of leach time. The average lime and cyanide consumptions were 1.75 kg/t and 0.78 kg/t, respectively. Vista is currently completing additional metallurgical test work at the target P80 40 micron size. However, for the purposes of classifying the heap leach material as a reserve, the previous recovery values were used.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 12 1.7 Mining Methods The Project is designed to be a conventional, owner-operated, large open-pit mining operation that will use large- scale mining equipment in a drill/blast/load/haul operation. All dollar values in Section 1.7 are reported in US$. A base gold price of US$1,250 per ounce was used for scenario analysis. However, various gold prices from US$300 to US$2,000 per ounce, in increments of US$20 per ounce, were used to determine different optimized pit shells. Economic parameters used for the pit designs are provided in Table 1-5. Table 1-5: Initial Economic Parameters Parameter Value Used Gold Recovery 85% Sulfide 80% Transition 80% Oxide Payable Gold 99.9% Overall Mining Cost US$1.90 per tonne mined Processing Cost US$7.80 per tonne processed Tailings US$0.90 per tonne processed General & Administrative US$0.46 per tonne processed Water Treatment US$0.09 per tonne processed Royalty 1% gross proceeds The mining costs used were varied by bench. An incremental cost of US$0.010 was added for each 6-meter bench below the 145 meter elevation. This represents the incremental increase in cost of haulage for both waste and ore for each bench that is to be mined. A reference mining cost of US$1.64 was used for pit optimization. Additionally, an incremental cost was determined based on truck operating costs, truck cycle time to haul and return through a 6-meter gain in elevation, and truck capacity. The reference mining cost was determined using first principles. The total mining cost (reference plus incremental) is US$1.90. Processing, tailings construction, tailings reclamation, and water treatment costs were provided by Vista. Calculated cutoff grade based on the economic parameters is 0.33 g-Au/t. At Vista’s request, the QP [Thomas L. Dyer, P.E.] used a minimum cutoff grade of 0.40 g-Au/t. This was done to maintain higher grades with respect to material allowed to be processed. The elevated cutoff grade of 0.40 g Au/t is appropriate for the Project.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 13 Several iterations of pit optimizations were reviewed to determine the final pit limits. A US$1,000/oz-Au pit shell was used to guide the ultimate pit design. Table 1-6 shows the WhittleTM optimization results. Note that the ultimate pit used for pit design is highlighted in orange. Table 1-6: WhittleTM Pit Optimization Results –Using 0.40 g-Au/t Cutoff Pit Gold Price (US$) Material Processed Waste Tonnes Total Tonnes Strip Ratio K Tonnes g-Au/t K Ozs Au 1 $ 300 3,282 1.77 186 2,797 6,078 0.85 6 $ 400 8,578 1.54 425 7,507 16,085 0.88 11 $ 500 15,988 1.34 686 15,740 31,728 0.98 16 $ 600 37,253 1.12 1,340 53,757 91,010 1.44 21 $ 700 89,301 0.99 2,855 171,617 260,918 1.92 26 $ 800 121,187 0.92 3,585 222,919 344,106 1.84 31 $ 900 159,485 0.87 4,442 316,889 476,374 1.99 36 $ 1,000 185,915 0.85 5,093 429,208 615,123 2.31 41 $ 1,100 212,340 0.84 5,741 566,907 779,247 2.67 46 $ 1,200 230,587 0.83 6,184 675,714 906,302 2.93 49 $ 1,250 234,858 0.83 6,278 700,519 935,376 2.98 51 $ 1,300 240,195 0.83 6,416 742,833 983,029 3.09 56 $ 1,400 243,306 0.83 6,498 771,190 1,014,497 3.17 61 $ 1,500 249,389 0.83 6,658 829,933 1,079,321 3.33 66 $ 1,600 254,050 0.83 6,779 880,583 1,134,633 3.47 70 $ 1,700 254,348 0.83 6,785 883,222 1,137,571 3.47 74 $ 1,800 259,140 0.83 6,908 943,012 1,202,152 3.64 78 $ 1,900 259,964 0.83 6,927 952,872 1,212,836 3.67 81 $ 2,000 260,099 0.83 6,929 953,985 1,214,083 3.67 Pit 36 was used for design purposes. 1.8 Metallurgy The flowsheet consists of primary crushing, closed circuit secondary crushing, closed circuit tertiary crushing using high pressure grinding rolls (HPGRs), ore sorting, two-stage grinding, cyclone classification, pre-leach thickening, leach and adsorption, elution electrowinning and smelting, carbon regeneration, tailings detoxification and disposal to conventional tailings storage facility (TSF). Figure 1-5 provides the schematic diagram of the flowsheet.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 14 Figure 1-5: Mt Todd Flowsheet

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 15 1.9 Mineral Processing Detailed design criteria have been developed for the process plant. The nominal headline design criteria are listed in Table 1-7 below. Table 1-7: Headline Design Criteria Unit Value Used Annual Ore Feed Rate Mt/a 17.75 Operating Days per Year d/a 355 Daily Ore Feed Rate t/d 50,000 Crushing Rate (6,637 hours per year availability) tph 2,674 HPGR Rate (7,838 hours per year) tph 2,264 Ore Sorting Rate (7,838 hours per year) tph 408 Milling Rate (7,838 hours per year) tph 2,055 Gold Head Grade1 g/t 0.82 Copper Head Grade % 0.055 Cyanide Soluble Copper % 0.0024 Bulk Density t/m3 2.76 Primary Grind P80 to Secondary Grind μm 250 Grind P80 to Leach μm 40 Gold Recovery % 91.9 Gold Production (average)2 oz/d 1,165 Gold Production (average) oz/a 413,400 1 Weighted average between pit ore at 0.84 g Au/t and heap leach ore at 0.54 g Au/t] 2 Based on block-by block total using constant tailing by specific feed grade range (Table 13-28) 1.10 Project Infrastructure Access to local resources and infrastructure is excellent. The Project is located sufficiently close to the city of Katherine to allow for an easy commute for workers. The area has both historic and current mining activity and therefore a portion of the skilled workforce will be sourced locally. In addition, Katherine offers the necessary support functions that are found in a medium-sized city with regard to supplies, accommodations, communications, etc. The property has an existing high-pressure gas line and an electric power line that were used by previous operators. In addition, wells for potable water and a dam for process water are also located on or adjacent to the site. Finally, a side hill-type TSF is present on site. Planned infrastructure for the site includes the following: „ Ammonium Nitrate and Fuel Oil (ANFO) Facility; „ Mine Support Facilities (Heavy Vehicle (HV) Workshop, Lube Farm, Washdown and Tire Change, Warehouse, Fuel Farm, Mining Offices, Core Storage Facility);

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 16 „ Heap Leach Pad (existing); „ Accommodation Camp; „ Water Treatment Plant (WTP); „ Power Supply; „ Pit Dewatering; „ Mine Services; „ Communications; „ Gatehouse; and „ Expanded existing and additional TSF. 1.11 Market Studies and Contracts 1.11.1 Markets Gold metal markets are mature, with many reputable refiners and brokers located throughout the world. The advantage of gold, like other precious metals, is that virtually all production can be sold in the market. As such, market studies, and entry strategies are not required. Metallurgical process studies confirm that the Project will produce doré of a specification comparable with existing operating mines. Demand is presently high with prices showing remarkable increases during recent times. The 36-month average London PM gold price fix through August 31, 2019 was US$1,279/oz. 1.11.2 Contracts Currently there are no contracts in place for development and operations. However, Vista has obtained budgetary quotes, as is common for PFS level studies, for future materials and service needs. The following contracts are expected to be in place upon project commencement: „ Secure doré transportation to refinery; „ Doré refining; „ Supplier and service contracts including; ⎯ EPCM; ⎯ Equipment supply; ⎯ D&C; ⎯ Diesel and fuel oil; ⎯ Natural gas for the power plant; ⎯ Process reagents; ⎯ Equipment preventive maintenance and repair (MARC) services; ⎯ Site security services; and ⎯ Camp management, catering and support services.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 17 1.12 Social and Environmental Aspects 1.12.1 Existing Environmental and Social Information A number of environmental studies have been conducted at the Project to obtain environmental and operational permits. Studies conducted have investigated soils, climate and meteorology, geology, geochemistry, biological resources, cultural and anthropological sites, socio-economics, hydrogeology, and water quality. In January 2018, the “authorization of a controlled activity” was received for the Project as required under the Australian Environmental Protection and Biodiversity Conservation Act of 1999 (EBPC) as it relates to the Gouldian Finch, and as such has received approval from the Australian Commonwealth Department of Environment and Energy. The Mt Todd Project Environmental Impact Statement (EIS) submitted June 28, 2013 to the Northern Territory Environment Protection Authority (NTEPA), approved in September 2014, provides an understanding of the existing environmental conditions and an assessment of the environmental impact of the Project. 1.12.2 Social or Community Requirements Vista has a good relationship with the Jawoyn. Areas of aboriginal significance have been designated, and the mine plan has avoided development in these restricted works areas.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 18 1.12.3 Approvals, Permits and Licenses The Project will require approvals, permits and licenses for various components of the Project. Table 1-8 includes a list of approvals, permits, and licenses required for the Project and their current status. Table 1-8: Mt Todd Permit Status Approval/ Permit/ License Current Status Approval/ Permit License Date Expiration Date Environmental Impact Statement The NT Environmental Protection Authority provided its final assessment of the Project in June 2014. Approved Sep. 2014 NA Mining Management Act (or Plan) Approval from NT Department of Primary Industry and Resources Mine operating permit request has been submitted. The MMP submitted in November 2018 is for 50kt/day operations. Prior to commencing mine operations NA Heritage Act permit to destroy or damage archeological sites and scatters/ Aboriginal Areas Protection Authority Clearances Authority Certificate Number 2011/15538 issued. This certificate defined restricted works areas and granted select clearances to allow for initial investigations. Additional clearances will be required for further investigations as well as prior to disturbance associated with mine development. Aboriginal Areas Protection Authority dated Jul. 31, 2012 NA Dangerous Goods Act (1988) permit for blasting activities Waiting on final mine plan NA NA Extractive Permit (under DME Guidelines) for development of borrow pits outside of approved mining areas Would be required for PGM or LPM borrow areas. Permit application not yet in progress pending final selection of borrow areas NA NA Waste Discharge License (under Section 74 of the Water Act 1992) for management of water discharge from the site WDL 178-6 licensing discharge of waste water into the Edith River from the Mt Todd mine site, granted with conditions Nov. 26, 2018 Nov. 30, 2020 Waste water treatment system permits under Public Health Act 1987 and Regulations May be required for the waste water treatment system for the construction and operations accommodation village. Permit application not yet in progress pending design and siting of accommodation village. NA NA Approval to Disturb Site of Conservation Significance (SOCS) Batman pit expansion will disturb SOCS as breeding / foraging habitat for the Gouldian finch, pending determination on EIS. Jan. 22, 2018 NA

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 19 1.13 Capital and Cost Estimates 1.13.1 Capital Cost Estimates LoM capital cost requirements are estimated at US$1,222 million as summarized in Table 1-9. Initial capital of US$826 million is required to commence operations. At the end of operations, the Project will receive an estimated US$140 million credit for asset sales and salvage.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 20 Table 1-9: Estimated Capital Cost Summary (US$000s) Area Description Cont. (%) Initial Capital (US$000s) Sustaining Capital (US$000s) Total Capital (US$000s) Estimate Contingency Total Estimate Contingency Total Estimate Contingency Total 2000 Mining 7.3% $121,239 $5,720 $126,958 $406,347 $32,677 $439,024 $527,586 $38,396 $565,982 3000 Process Plant 13.9% $366,693 $51,073 $417,766 $17,027 $2,222 $19,249 $383,720 $53,295 $437,016 4000 Project Services 10.0% $109,204 $12,681 $121,885 $72,448 $5,455 $77,903 $181,651 $18,136 $199,787 5000 Project Infrastructure 13.2% $26,160 $3,463 $29,623 $0 $0 $0 $26,160 $3,463 $29,623 6000 Permanent Accommodation 10.0% $60 $6 $66 $0 $0 $0 $60 $6 $66 7000 Site Establishment & Early Works 11.4% $17,537 $1,995 $19,532 $0 $0 $0 $17,537 $1,995 $19,532 8000 Management, Engineering, EPCM Services 11.8% $82,058 $9,721 $91,779 $0 $0 $0 $82,058 $9,721 $91,779 9000 Pre-Production Costs 12.3% $16,121 $1,982 $18,102 $0 $0 $0 $16,121 $1,982 $18,102 10000 Asset Sale 0.0% $0 $0 $0 ($139,631) $0 ($139,631) ($139,631) $0 ($139,631) Capital Cost 11.6% $739,072 $86,641 $825,712 $356,191 $40,354 $396,545 $1,095,263 $126,994 $1,222,257

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 21 1.13.2 Operating Cost Estimates LoM operating costs requirements are estimated to be US$15.18/t-milled as summarized in Table 1-10. Table 1-10: Estimated LoM Operating Costs (US$) Description US$/t-milled US$/t-moved OPEN PIT MINE Mine General Service 0.10 0.03 Mine Maintenance 0.11 0.03 Engineering 0.05 0.01 Geology 0.03 0.01 Drilling 0.77 0.23 Blasting 1.17 0.35 Loading 0.60 0.18 Hauling 2.74 0.83 Mine Support 0.43 0.13 Mine Dewatering 0.01 0.004 Open Pit Mine 6.02 1.82 CIP PROCESS PLANT Labor 0.79 - 3100-Crush/Screen/Stockpile 0.18 - 3200-Reclaim & HPGR 0.44 - 3300-Classification & Grinding 3.14 - 3400-Pre-Leach,Thick/Aeration/CIP 0.13 - 3500-Desorption, Gold Room 0.02 - 3600-Detox & Tailings Pumping 0.06 - 3700-Reagents 2.98 - 3800-Plant Services 0.04 - Mining, Infrastructure & Misc 0.06 - General Consumables 0.01 - Plant Mobile Equipment 0.01 - Plant Gas Consumption 0.03 - CIP Process Plant 7.88 - Project Services $0.16 - G&A $1.11 - Operating Costs $15.18 -

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 22 1.14 Financial Analysis 1.14.1 Financial Analysis Estimated economic results are summarized in Table 1-11. The analysis suggests the following conclusions, assuming a 100% equity project at a gold price of US$1,350: „ Mine Life: 13 years; „ Pre-Tax NPV5%: US$1,440 million, IRR: 30.4%; „ After-tax NPV5%: US$823 million, IRR: 23.4%; „ Payback (After-tax): 2.9 years; „ NT Royalty Paid: US$473 million; „ Australian Income Taxes Paid: US$553 million; and „ Cash costs (including JAAC Royalty): US$645.14/oz-Au. Table 1-11: Estimated Technical-Economic Results (US$000s) Cash Flow Summary LoM (US$000s) Unit Cost US$/t-milled US$/oz-Au Gold Sales Gold Produced (koz) 5,305 - - Gold Price (US$/oz) 1,350 - - Gold Sales 7,161,494 32.40 1,300 Refining & Royalties Refinery Costs (17,075) (0.077) (3.22) JAAC Royalty (71,615) (0.324) (13.50) Gross Income from Mining 7,072,805 31.998 1,333 Operating Costs Open Pit Mine (1,330,976) (6.02) (251) CIP Process Plant (1,742,519) (7.88) (328) Project Services (35,007) (0.16) (6.60) G&A (246,285) (1.11) (46.43) Operating Costs (3,354,787) (15.18) (632.40) Power Sales Credit 21,156 0.096 3.99 Cash Cost of Goods Sold (COGS) (3,422,321) (15.48) (645.14) Operating Margin 3,739,174 16.92 704.86 Capital Costs Mining 565,982 Process Plant 437,016 Project Services 199,787 Project Infrastructure 29,623 Permanent Accommodation 66

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 23 Cash Flow Summary LoM (US$000s) Unit Cost US$/t-milled US$/oz-Au Site Establishment & Early Works 19,532 Management, Engineering, EPCM Services 91,779 Pre-Production Costs 18,102 Asset Sale (139,631) Capital Costs 1,222,257 Pre-Tax Cash Flow 2,511,917 NPV5% 1,440,469 IRR (%) 30.4% After-tax Cash Flow 1,439,863 NPV5% 823,125 IRR (%) 23.4% After-tax Payback (years) 2.9 1.15 Conclusions and Recommendations 1.15.1 Feasibility Study A Feasibility Study (FS) should be completed to advance the Project and provide additional detailed information necessary to support capital and operating cost estimates for a potential project development decision. The estimated budget for the FS is approximately US$2.5M – 4.0M. 1.15.2 Geology and Resources 1.15.2.1 Conclusions „ The Project is situated within the southeastern portion of the Early Proterozoic Pine Creek Geosyncline which is comprised of the Burrell Creek Formation, the Tollis Formation, and the Kombolgie Formation. „ Gold mineralization in this area is constrained to a single mineralization event and the deposits are classified as orogenic gold deposits in the subdivision of thermal aureole gold style. The Batman deposit has characteristics of an intrusion related gold system making it the primary resource. „ The Batman deposit is defined by approximately 7.4 million ounces (Moz) of gold within 278 Mt of measured and indicated resource at an average grade of 0.82 g-Au/t and a cutoff grade of 0.4 g-Au/t. as provided in Table 1-3.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 24 1.15.2.2 Recommendations „ The Batman deposit potentially extends along strike both to the north and south. Step out drilling should be evaluated. „ Additional deep infill drilling should be used to help define potential deep mineralization not detected by early historical drillholes. „ Infill drilling within and exploration drillholes along the trend of the Quigleys deposit is recommended. „ Exploration of the exploration licenses, including work on geophysical and geochemical anomalies, should continue in a systematic manner. The estimated budget for drilling within the MLs is US$500,000-1,000,000 and US$500,000-1,000,000 for initial drilling on the ELs. 1.15.3 Mineral Reserve and Mine Planning „ Pit designs were completed based on WhittleTM pit optimizations and are appropriate for metal prices of approximately US$1,000 per ounce Au. The Mt Todd proven and probable reserve estimates have been defined using economics based on a gold price of US$1,250 per ounce and an elevated cutoff grade of 0.40 g-Au/t. The proven and probable reserve estimates were used to create a production schedule for mining, and a positive cash-flow analysis has been done based on the production schedule. The reserve estimates have reasonable economics with respect to the statement of reserves under NI 43-101 regulations. „ Mine production constraints were imposed to ensure that mining wasn’t overly aggressive with respect to the equipment anticipated for use at Mt Todd. The schedule has been produced using mill targets and stockpiling strategies to enhance the project economics. The constraints and limits are reasonable to support the project economics which are used to justify the statement of reserve estimates. „ Pit designs use six-meter benches for mining. This corresponds to the resource model block heights, and the QP [Thomas L. Dyer, P.E.] believes this to be reasonable with respect to dilution and equipment anticipated to be used in mining. In areas where the material is consistently ore or waste so that dilution is not an issue, benches may be mined in 12 m heights. 1.15.4 Mineral Processing 1.15.4.1 Conclusions The substantial quantity and quality of metallurgical test work data developed from Mt Todd drill core samples has led to the development of a robust, energy-efficient comminution circuit followed by a standard gold recovery process. Key conclusions drawn from the metallurgy studies are: „ Mt Todd (Batman) ore is among the hardest and most competent ore types processed for mineral recovery. The most energy efficient comminution circuit has been determined to be the sequence of primary crushing, closed circuit secondary crushing, and closed circuit HPGR tertiary crushing and ore sorting followed by two stages of grinding.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 25 „ The ore is free-milling, is not preg-robbing, and is amenable to gold extraction by conventional cyanidation processes. „ The ore has moderately high cyanide consumption, determined to be 0.876 kg of sodium cyanide per tonne of ore. This is largely due to the presence of sulfides and cyanide consuming copper and destruction of residual cyanide. „ The use of sorting has helped to decrease operational costs by removing portions of the uneconomic material mined. „ Achieving a finer grind with a two-stage grinding circuit resulted in significant improvement in gold extraction. The equipment selection criteria for the operation has received considerable interaction with specialist vendors to the point where there is a reasonably high-degree of confidence in selected technology and process units at this preliminary feasibility study stage. The recommended flowsheet for a FS consists of primary crushing, closed circuit secondary crushing, closed circuit tertiary crushing using HPGRs and ore sorting, two-stage grinding, cyclone classification, secondary grinding, cyclone classification, pre-leach thickening, leach and adsorption, elution electrowinning and smelting, carbon regeneration, tailings detox and disposal to conventional tailings storage facility. 1.15.4.2 Recommendations The on-going testwork is directed towards optimization of the process parameters. The study would potentially lead to reduction of reagent usage thereby reducing operating costs. In addition, the potential of increasing leach pulp density is being evaluated which could result in reducing size of leach tanks and hence capital cost. 1.15.5 Infrastructure „ Bulk earthworks are designed to minimize the import of fill materials. „ Administration offices, gatehouse/security facilities, cribs/ablutions are planned to be transportable buildings. „ The process plant offices, workshop and warehouse are located inside the existing Flotation Building. „ Sample preparation and laboratory will have a purpose-built steel shed. „ The access road is based on the repaired existing road. „ Heavy cranage is allowed for all lifts greater than 50 t. „ All bulk transport will be weighed. „ Site-wide communication is based on a 50 m tall communication tower that will support eight channels.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 26 1.15.6 Environmental and Social Impacts 1.15.6.1 Conclusions A number of environmental studies have been conducted at the Project Site in support of the Environmental Impact Statement (EIS) and as required for environmental and operational permits. Studies conducted have investigated soils, climate and meteorology, geology, geochemistry, biological resources, cultural and anthropological sites, socio-economics, hydrogeology, and water quality. The draft EIS for the Project was submitted in June 2013. The document was prepared by independent consultants GHD Pty Ltd to identify potential environmental, social, transport, cultural and economic impacts associated with reopening and operating the mine. The Northern Territory Environmental Protection Authority (NTEPA) provided its final assessment of the Project in June 2014. Final approval was given in September 2014. In January 2018, the “authorization of a controlled activity” was received for the Project as required under the Australian Environmental Protection and Biodiversity Conservation Act of 1999 (EBPC) as it relates to the Gouldian Finch, and as such has received approval from the Australian Commonwealth Department of Environment and Energy. Areas of aboriginal significance have been designated, and the mine plan has avoided development in these restricted works areas. 1.15.6.2 Recommendations Additional studies will be needed to further assess environmental baseline conditions to support feasibility level design, permitting, and closure planning for the Project, including: „ Erosion analyses; „ Waste and cover material hydraulic properties characterization and analysis; „ Ongoing aquatic, benthic, and wildlife studies; „ Comprehensive vegetation survey; „ Archaeological and historical assessments for all areas to be disturbed; „ Further hydrogeologic investigations and site-wide hydrogeologic characterization; and „ Continued precipitation, stream flow, and watershed data. The estimated budget for this work is US$350,000.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 27 1.15.7 Results of the Site-wide Water Balance Model 1.15.7.1 Conclusions Under the modeled conditions: „ The WTP rate of 500 m3/hr and process water pond (PWP) sizing for 6 days of storage appear adequate for the 50,000 tpd production process water requirements. „ The greatest amount of make-up water required from the raw water dam (RWD) was quantified as 11,955 m3/day. RWD requirements were found to be the most dependent upon TSF decant volumes. „ The Waste Rock Dump (WRD) retention pond (RP1), low grade ore stockpile retention pond (LGRP), process plant retention pond (PRP), and heap leach pad (HLP) were typically observed to overtop less than 1% of the time during the 13-year simulation.[1] LGRP storage may be optimized. 1.15.7.2 Recommendations Additional model improvements to refine the TSF water balance model, refine pit parameters in the water balance model, explore WTP effluent use options during the dry season, evaluate storage capacity requirements of RP1, expand the RWD parameters to include stage storage and catchment area elements, include additional water storage in tanks on-site, further evaluate dust suppression, and assess water balance model sensitivity are recommended. The estimated budget for this work is US$200,000. 1.15.8 Groundwater Hydrology and Mine Dewatering The following work is recommended with respect to groundwater hydrology and mine dewatering: „ Additional hydrogeologic study should be completed in the vicinity of the Batman Pit to provide more detailed information on which to base calibration of the regional groundwater flow model and subsequent prediction of groundwater inflows to the pit and post-mining recovery of the groundwater system. The study should also include measurement of depth to water in any accessible existing borings or core holes within or immediately adjacent to the pit. „ Calibration of the regional groundwater flow model should be completed with the additional data, and the calibrated model should be used to refine the estimates of groundwater inflow to the pit and predictions of the hydrogeologic effects of pit dewatering. „ The post-mining version of the groundwater flow model should be updated with the calibrated model used as its basis. Output from the post-mining model should be incorporated into any geochemical modeling of post-mining pit lake formation and geochemistry. The estimated budget for this work is US$400,000. [1] A typical value is given. Separate model runs provide a range of overtopping events, due to the stochastic nature of the model.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 28 1.15.9 Process Plant Geotechnical Investigation 1.15.9.1 Conclusions There are no conclusions with regard to the Process Plant geotechnical investigation. 1.15.9.2 Recommendations Future geotechnical work is recommended during final engineering design, particularly for foundation design of the processing facilities. The estimated budget for this work is US$150,000. 1.15.10 TSF Design As part of advancing the TSF design in the FS, work should include optimization of the TSF construction schedule, geotechnical investigation and assessment of TSF 1 and TSF 2, TSF water balance update, and TSF consequence classification. The estimated budget for this work is included in the FS budget estimate. 1.15.11 Process Two major items incurring operating costs are grinding media and reagents. Together these items make up 61% of the plant consumables operating costs. The FS should investigate options for reducing the consumption rate and the unit costs for these consumables. The estimated budget for this work is included in the FS budget estimate. 1.15.12 Geochemical Analyses Geochemical characterization will be updated to reflect the designations of Potentially Acid Forming, Potentially Acid Forming-Low Capacity, Non Acid Forming, Acid Consuming and Uncertain in accordance with DITR (2007) guidelines. Additional geochemical testing is recommended on the sorter reject material. The estimated budget for this work is included in the Feasibility Study.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 29 2.0 INTRODUCTION Vista Gold Corp. and its subsidiaries (collectively, “Vista” or the “Company) operate in the gold mining industry. The Company is focused on the evaluation, acquisition, exploration and advancement of gold exploration and potential development projects, which may lead to gold production or value adding strategic transactions such as earn-in right agreements, option agreements, leases to third parties, joint venture arrangements with other mining companies, or outright sales of assets for cash and/or other consideration. Vista looks for opportunities to improve the value of its gold projects through exploration drilling and/or technical studies focused on optimizing previous engineering work. Vista does not currently generate cash flows from mining operations. The Company’s flagship asset is its 100% owned Mt Todd gold Project (Mt Todd) in the Northern Territory (NT) Australia. The Company recently received authorization for the last major environmental permit and completed an updated PFS for Mt Todd, which confirms the project’s robust economics at today’s gold price. With these important milestones complete, Vista is in a position to actively pursue those strategic alternatives that provide the best opportunity to maximize value for the Company. Vista Gold Corp. was originally incorporated on November 28, 1983 under the name “Granges Exploration Ltd.” It amalgamated with Pecos Resources Ltd. during June 1985 and continued as Granges Exploration Ltd. In June 1989, Granges Exploration Ltd. changed its name to Granges Inc. Granges Inc. amalgamated with Hycroft Resources & Development Corporation during May 1995 and continued as Granges Inc. Effective November 1996, Da Capo Resources Ltd. and Granges, Inc. amalgamated under the name “Vista Gold Corp.” and, effective December 1997, Vista continued from British Columbia to the Yukon Territory, Canada under the Business Corporations Act (Yukon Territory). On June 11, 2013, Vista continued from the Yukon Territory, Canada to the Province of British Columbia, Canada under the Business Corporations Act (British Columbia). 2.1 Background Information Vista Gold Corp. (Vista) retained Tetra Tech, Inc., along with JDS Energy & Mining, Inc. (JDS), Mine Development Associates (MDA), Resource Development Inc. (RDi), Tetra Tech Proteus (TTP), and POWER Engineers, Inc. (POWER) to prepare this PFS for its Mt Todd Gold Project (the Project) in Northern Territory (NT), Australia. The PFS (Technical Report) evaluates a development scenario of a 50,000 tonne per day (tpd) processing facility. The 50,000 tpd operation includes: „ Estimated proven and probable reserves of 5.848 Moz of gold (221 Mt at 0.82 g-Au/t) at a cut-off grade of 0.40 g-Au/t; „ Average annual production of 381,211 ounces of gold per year over the mine life, including average annual production of 479,450 ounces of gold per year during the first five years of operations; „ LoM average cash costs of US$645 per ounce, including average cash costs of US$575 per ounce during the first five years of operations; „ A 13-year operating life;

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 30 „ After-tax NPV5% of US$823 million and internal rate of return (IRR) of 23.4% at US$1,350 per ounce gold prices and US$0.70:AUD1.00 exchange rate, and „ Initial capital requirements of US$826 million. 2.2 Terms of Reference and Purpose of the Report This Technical Report was prepared as a NI 43-101 Technical Report for Vista by Tetra Tech. The quality of information, conclusions, and estimates contained herein are consistent with the level of effort involved in Tetra Tech’s services, based on: i) information available at the time of preparation, ii) data supplied by outside sources, and iii) the assumptions, conditions, and qualifications set forth in this report. This report provides mineral resource and mineral reserve estimates, and a classification of resources and reserves in accordance with the CIM Standards. The CIM Standards requires the completion of a PFS as the minimum prerequisite for the conversion of mineral resources to mineral reserves. A preliminary feasibility study is a comprehensive study of a range of options for the technical and economic viability of a mineral project that has advanced to a stage where a preferred mining method and the open pit configuration is established and an effective method of mineral processing is determined. It includes a financial analysis based on reasonable assumptions on the modifying factors and the evaluation of any other relevant factors which are sufficient for a QP, acting reasonably, to determine if all or part of the mineral resource may be converted to a mineral reserve at the time of reporting. Modifying factors are considerations used to convert mineral resources to mineral reserves. These include, but are not restricted to, mining, processing, metallurgical, infrastructure, economic, marketing, legal, environmental, social and governmental factors. A PFS is at a lower confidence level than a Feasibility Study (FS). 2.3 Sources of Information The primary technical documents and files relating to the Project that were used in the preparation of this report are listed in Section 27.0 – References. 2.4 Units of Measure The metric system has been used throughout this report. Tonnes are metric of 1,000 kilograms (kg), or 2,204.6 pounds (lb). Gold is reported in troy ounces (oz), equivalent to 31.1035 grams (g). Currency is in Q3 2019 U.S. dollars (US$) unless otherwise stated. 2.5 Detailed Personal Inspections 1) Rex Bryan visited and inspected the property from September 12th, 2011 to September 14th, 2011 and February 6th, 2013 to February 8th, 2013. Rex Bryan last visited and inspected the property June 28–29, 2017. Dr. Bryan spent time on site and reviewed the current database and archived supporting material, core logging, sampling procedures, handling and security measures, QA/QC procedures and inspected modern and historically collected core. 2) Anthony Clark last visited and inspected the property June 28–29, 2017. Mr. Clark inspected the existing power infrastructure at the site, natural gas pipeline, and power rights-of-way.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 31 3) Thomas Dyer visited and inspected the subject property during March, 2011. Thomas Dyer last visited and inspected the property June 28–29, 2017. Mr. Dyer toured the site along with geotechnical consultants and reviewed the pit, waste dump, tailings facility, and resource drilling sites. Previous mine production records held on site were also reviewed. 4) Chris Johns visited and inspected the property June 28–29, 2017. Mr. Johns inspected the existing Tailings Storage Facility 1 (TSF 1) and the proposed site for Tailings Storage Facility 2 (TSF 2). 5) Zvonimir Ponos last visited and inspected the property June 28–29, 2017. Mr. Ponos inspected the existing site infrastructure and process facility. 6) Vicki J. Scharnhorst visited and inspected the property June 28–29, 2017. Ms. Scharnhorst inspected the infrastructure at site and reviewed the status of environmental permitting with site staff. QPs not listed above have not visited or inspected the property. Personal inspections by these QPs are not required to complete their responsibilities. The QPs consider the 2017 site visits current personal inspections on the basis that the work completed on the property since that time has been reviewed and the QPs are of the opinion that the limited work carried out on the property since 2017 is not material. The QPs are satisfied that no unauthorized access or other work has been conducted on the property based on the site security including site access via a paved road through a locked security gate combined with the fact that the site is continuously manned by company personnel. Further, the Jawoyn Association Aboriginal Corporation (JAAC) rangers regularly patrol the area around the site. With regard to specific conditions at the site, the hardness and average grade of the Batman deposit rock make the potential for theft or high-grading by unauthorized persons very low. Finally, the QPs also review publicly available information on the Company and its activities including the audited financial statements of the Company which the QPs are satisfied do not point to any additional work being conducted on the property.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 32 3.0 RELIANCE ON OTHER EXPERTS The QPs used their experience to determine if the information from previous reports was suitable for inclusion in this Technical Report. This report includes technical information which required subsequent calculations to derive subtotals, totals and weighted averages. Such calculations inherently involve a degree of rounding and consequently introduce a margin of error. Where these occur, the QPs do not consider them to be material. The QP [Vicki J. Scharnhorst, P.E.] relied upon the following experts to prepare portions of Section 20 - Environmental Studies, Permitting, and Social or Community Impact: „ Environmental Impact Statement for the Project prepared by GHD (June 2013) was used to describe the existing environmental studies (Section 20.1).

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 33 4.0 PROPERTY DESCRIPTION AND LOCATION 4.1 Location The Project is located 56 kilometers (km) by road northwest of Katherine, and approximately 290 km southeast of Darwin in NT, Australia (Figure 4-1). Access to the property is via high quality, two-lane paved roads from the Stuart Highway, the main arterial within the territory. 4.2 Property Description Vista Australia is the holder of four mineral licenses (ML) MLN 1070, MLN 1071, MLN 1127, and MLN 31525 comprising approximately 5,544 hectares (ha). In addition, Vista Australia controls exploration licenses (EL) EL 29882, EL 29886, EL 30898, and EL 28321 comprising approximately 153,700 ha. Figure 4-2 illustrates the general location of the tenements and the position of the Batman deposit. A general arrangement is provided in Figure 4-3. 4.3 Lease and Royalty Structure Vista Australia entered into a lease agreement (the Lease Agreement) with the NT government for an initial term of five years commencing January 1, 2006, with an extension of five years at Vista Australia’s option and three additional years upon the application of Vista Australia and with the approval of the NT government. Pursuant to the conditions of the first five-year term of the Lease Agreement, Vista Australia undertook a comprehensive technical and environmental review of the Project to evaluate site environmental conditions and developed a program to stabilize the environmental conditions and minimize offsite contamination. Vista also reviewed the water management plan and made recommendations and developed a Technical Report for the re-starting of operations. During the term of the Lease Agreement, Vista Australia was also required to examine all technical, economic, and environmental issues, estimate the cost to rehabilitate the site, explore and evaluate the potential of the Project, and prepare a technical and economic feasibility study for the potential development of the Project site. Vista provided notice to the NT government in June 2010 that it wished to extend the Lease Agreement. In November 2010, the NT government granted the renewal and the Lease Agreement was extended for an additional five years to December 31, 2015. The NT government renewed the Lease Agreement by deed of variation in 2014 and again in May 2017, extending it to December 31, 2023. Vista Australia paid the NT government's costs of management and operation of the Project Site up to a maximum of AUD375,000 during the first year of the term, and assumed site management and management and operation costs in the following years. In the agreement, the NT government acknowledges its commitment to rehabilitate the site and the Lease Agreement provides that Vista Australia has no rehabilitation obligations for pre-existing environmental conditions until it submits and receives approval of a Mining Management Plan (MMP) for the resumption of mining operations. The most recent MMP (Vista Gold Australia 2018) addresses activities undertaken by Vista with respect to site management, infrastructure maintenance and environmental management (Section 20.3 – Permitting and Authorizations). Recognizing the importance placed by the NT government upon local industry participation, Vista Australia has agreed to use, where appropriate, NT-sourced labor and services during the period of the Lease

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 34 Agreement in connection with the Mt Todd property, and further, in connection with any proposed mining activities prepare and execute a local Industry Participation Plan. Pursuant to an agreement (the JAAC Agreement) with the Jawoyn Association Aboriginal Corporation (JAAC), Vista was required to issue Vista common shares with a value of Canadian dollars (CAD) 1.0 million as consideration for the JAAC entering into the JAAC Agreement and as rent for the use of the surface lands overlying the mineral leases during the period from the effective date of the agreement until a decision is reached to begin production. For rent of the surface rights from the current mining licenses, including the mining license on which the Batman deposit is located, the JAAC is entitled to an annual amount equal to 1% of the gross value of production with a minimum annual payment of AUD50,000. Vista also pays the JAAC AUD5,000 per month for consulting with respect to aboriginal, cultural, and heritage issues. If the Project proves feasible and subject to several conditions, Vista has agreed to offer the JAAC the opportunity to establish a joint venture company with Vista holding 90% and the JAAC holding a 10% participating interest, with each party being responsible to finance and provide funding for its respective develop costs of the Project. There is also a royalty of 5% of based on the gross value of any gold or other metals that may be commercially extracted from certain mineral concessions (the Denehurst Royalty). The Denehurst Royalty would not apply to any presently identified mineralized zones at Mt Todd.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 35 Figure 4-1: General Project Location Map

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 36 NOTE: Prepared by Vista Gold Corp.; updated on February 23, 2018 Figure 4-2: Concessions

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 37 Figure 4-3: General Arrangement

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 38 4.4 Risks Vista is in sole possession of the title and rights to perform work on the Project. Surface access is guaranteed through Vista’s agreement with the JAAC. Exploration or other similar activities require a MMP to be submitted to the Department of Regional Development, Primary Industry, Fisheries and Resources (DRDPIFR) with approvals typically occurring in thirty or less days. Vista has been in sole possession of the site for approximately 13 years and no MMPs have ever been withheld with regard to exploration or other activities.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 39 5.0 ACCESSIBILITY, CLIMATE, LOCAL RESOURCES, INFRASTRUCTURE AND PHYSIOGRAPHY 5.1 Accessibility The Project is located 56 km by road northwest of Katherine, and approximately 290 km southeast of Darwin in the NT of Australia. Access to the mine is via high quality, two-lane paved roads from the Stuart Highway, the main artery within the territory. 5.2 Climate and Physiography The Project area has a sub-tropical climate with a distinct wet season and dry season. The area receives most of its rainfall between the months of January and early March. During these months, the temperature usually ranges from 25° to 35°C, but temperatures can reach as high as 42°C. Winter temperatures in the dry season usually range from 14°C to 20°C, but can drop to as low as 10°C at night. Mining and processing operations are planned year-round; however, pit dewatering will be required after large precipitation events. 5.3 Local Resources and Infrastructure Access to local resources and infrastructure is excellent. The Project is located sufficiently close to the city of Katherine to allow for an easy commute for workers. The area has both historic and current mining activity and therefore a portion of the skilled workforce will be sourced locally. In addition, Katherine offers the necessary support functions that are found in a medium-sized city with regard to supplies, accommodations, communications, etc. The property has an existing high-pressure gas line and an electric power line that was used by previous operators. In addition, wells for potable water and a dam for process water are also located on or adjacent to the site. Finally, a fully functioning tailings dam is present on site. The concessions are within 2 to 3 km of the Nitmiluk Aboriginal National Park on the east. This National Park contains a number of culturally and geologically significant attractions. The proximity to the National Park has not historically yielded any impediments to operating. It is not expected to yield any issues to renewed operation of the property in the future. The Project is wholly contained within the Aboriginal Freehold Land and will require no additional acquisition of surface rights. 5.4 Topography, Elevation and Vegetation The topography of the Project is relatively flat. The mineral leases encompass a variety of habitats forming part of the northern Savannah woodland region, which is characterized by eucalypt woodland with tropical grass understories. Surface elevations are on the order of 130 to 160 meters (m) above sea level in the area of the previous and planned site and waste dumps.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 40 6.0 HISTORY The Project area has significant gold deposits. It is situated in a well-mineralized historical mining district that supported small gold and tin operations in the past. The Shell Company of Australia (Billiton), who was the managing partner in an exploration program in joint venture with Zapopan NL (Zapopan), discovered the Mt Todd mineralization, or more specifically the Batman deposit, in May 1988. Zapopan acquired Billiton’s interest in 1992 by way of placement of shares to Pegasus Gold Australia Pty. Ltd. (Pegasus). Pegasus progressively increased their shareholding until they acquired full ownership of Zapopan in July 1995. Preliminary studies for Phase I, a heap leach operation which focused predominately on the oxide portion of the deposit, commenced during 1992 culminating in an engineering, procurement, construction management (EPCM) award to Minproc in November of that year. The Phase I project was predicated upon a 4 million tonnes per year (Mtpy) on an annualized basis heap leach pad, which came on stream in late 1993. The treatment rate was subsequently expanded to a rate of 6 Mtpy on an annualized basis in late 1994. Historic production is shown in Table 6-1. Table 6-1: Heap Leach – Historic Actual Production Category Historic Production Actual Tonnes Leached (million) 13.2 Head Grade (g-Au/t) 0.96 Recovery (%) 53.8 Gold Recovered (oz) 220,755 Cost/t (AUD) 8.33 Cost/oz (AUD) 500 NOTE: All tonnages and grades are historic production numbers that pre-date Vista’s ownership. The QPs and issuer consider historic estimates to be relevant but not current. Phase II involved expanding to 8 Mtpy and treatment through a flotation and carbon-in-leach (CIL) circuit. The feasibility study was conducted by a joint venture between Bateman Kinhill and Kilborne (BKK, 1996) and was completed in June 1995. The Pegasus board approved the project on August 17, 1995, and awarded an EPCM contract to BKK in October 1995. Commissioning commenced in November 1996. Final capital cost to complete the project were AUD232 million (US$181 million). Design capacity was never achieved due to inadequacies in the crushing circuit. An annualized throughput rate of just under 7 Mtpy was achieved by mid-1997; however, problems with the flotation circuit which resulted in reduced recoveries necessitated closure of this circuit. Subsequently, high reagent consumption as a result of cyanide soluble copper minerals further hindered efforts to reach design production. Operating costs were above those predicted in the feasibility study.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 41 The spot price of gold deteriorated from above US$400 in early 1996 to below US$300 per ounce during 1997. According to the 1997 Pegasus Annual Report, the economics of the project were seriously affected by the slump. Underperformance of the project and higher operating costs led to the mine being closed and placed on care and maintenance on November 14, 1997. In February 1999, General Gold Resources Pty. Ltd. (General Gold) agreed to form a joint venture with Multiplex Resources Pty Ltd (Multiplex Resources) and Pegasus to own, operate, and explore the mine. Initial equity participation in the joint venture was General Gold 2%, Multiplex Resources 93%, and Pegasus 5%. The joint venture appointed General Gold as mine operator, which contributed the operating plan in exchange for a 50% share of the net cash flow generated by the project, after allowing for acquisition costs and environmental sinking fund contributions. General Gold operated the mine from March 1999 to July 2000. 6.1 History of Previous Exploration The Batman gold prospect is part of a goldfield that was worked from early in the 20th century. Gold and tin were discovered in the Mt Todd area in 1889. Most deposits were worked in the period from 1902 to 1914. A total of 7.80 tonnes of tin concentrate was obtained from cassiterite-bearing quartz-kaolin lodes at the Morris and Shamrock mines. The Jones Brothers reef was the most extensively mined gold-bearing quartz vein, with a recorded production of 28.45 kg Au. This reef consists of a steeply dipping ferruginous quartz lode within tightly folded greywackes. The Yinberrie Wolfram field, discovered in 1913, is located 5 km west of Mt Todd. Tungsten, molybdenum and bismuth mineralization was discovered in greisenized aplite dykes and quartz veins in a small stock of the Cullen Batholith. Recorded production from numerous shallow shafts is 163 tonnes of tungsten, 130 kg of molybdenite and a small quantity of bismuth. Exploration for uranium began in the 1950s. Small uranium prospects were discovered in sheared or greisenized portions of the Cullen Batholith in the vicinity of the Edith River. The area has been explored previously by Esso for uranium without any economic success. Australian Ores and Minerals Limited (AOM) in joint venture with Wandaroo Mining Corporation and Esso Standard Oil took out a number of mining leases in the Mt Todd area during 1975. Initial exploration consisted of stream sediment sampling, rock chip sampling, and geological reconnaissance for a variety of commodities. A number of geochemical anomalies were found primarily in the vicinity of old workings. Follow-up work concentrated on alluvial tin and, later, auriferous reefs. Backhoe trenching, costeaning, and ground follow-up were the favored mode of exploration. Two diamond drillholes were drilled at Quigleys. Despite determining that the gold potential of the reefs in the area was promising, AOM ceased work around Mt Todd. The Arafura Mining Corporation, CRA Exploration, and Marriaz Pty Ltd all explored the Mt Todd area at different times between 1975 and 1983. In late 1981, CRA Exploration conducted grid surveys, geological mapping and a 14-diamond drillhole program, with an aggregate meterage of 676.5 m, to test the gold content of Quigleys Reef over a strike length of 800 m. Following this program CRA Exploration did not proceed with further exploration. During late 1986, Pacific Gold Mines NL (Pacific Gold Mines) undertook exploration in the area which resulted in small-scale open cut mining on the Quigleys and Golf reefs, and limited test mining at the Alpha, Bravo, Charlie and Delta pits. Ore was carted to a carbon-in-pulp (CIP) plant owned by Pacific Gold Mines at Moline. This continued until December 1987. Pacific Gold Mines ceased operations in the area in February 1988 having produced approximately 86,000 tonnes grading 4 g-Au/t (historic reported production, presented for

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 42 context). Subsequent negotiations between the Mt Todd Joint Venture partners (Billiton and Zapopan) and Pacific Gold Mines resulted in the acquisition of this ground and incorporation into the joint venture. Table 6-2 presents important historical events in a chronologic order. Table 6-2: Property History 1986 October 1986 – January 1987: Conceptual Studies, Australia Gold PTY LTD (Billiton); Regional Screening (Higgins); Ground Acquisition, Zapopan N.L. 1987 February: June-July: October: Joint Venture finalized between Zapopan and Billiton. Geological Reconnaissance, Regional BCL, stream sediment sampling. Follow-up BCL stream sediment sampling, rock chip sampling and geological mapping (Geonorth) 1988 Feb-March: March-April: May: May-June: July: July-Dec: Data reassessment (Truelove) Gridding, BCL grid soil sampling, grid based rock chip sampling and geological mapping (Truelove) Percussion drilling Batman (Truelove) - (BP1-17, 1475m percussion) Follow-up BCL soil and rock chip sampling (Ruxton, Mackay) Percussion drilling Robin (Truelove, Mackay) – RP 1-14, (1584m percussion) Batman diamond, percussion and reverse circulation (RC) drilling (Kenny, Wegmann, Fuccenecco) – B P18-70, (6263m percussion); BD1-71, (8562m Diamond); BP71-100, (3065m R.C.) 1989 Feb-June: June: July-Dec: Batman diamond and RC drilling: BD72-85 (5060m diamond); BP101-208, (8072m RC). Penguin, Regatta, Golf, Tollis Reef Exploration Drilling: PP1-8, PD1, RGP1-32 GP1-8, BP108, TP1-7 (202m diamond, 3090m RC); TR1-159 (501m RAB). Mining lease application (MLA's 1070, 1071) lodged. Resource estimates; mining-related studies; Batman EM-drilling: BD12, BD8690 (1375m diamond); RC pre-collars and H/W drilling, BP209-220 (1320m RC); Exploration EM and exploration drilling: Tollis, Quigleys, TP9, TD1, QP1-3, QD1-4 (1141 diamond, 278m RC); Negative Exploration Tailings Dam: E1-16 (318m RC); DR1-144 (701. RAB) (Kenny, Wegmann, Fuccenecco, Gibbs). 1990 Jan-March: Pre-feasibility (PFS) related studies; Batman Inclined Infill RC drilling: BP222-239 (2370m RC); Tollis RC drilling, TP10-25 (1080m RC). (Kenny, Wegmann, Fuccenecco, Gibbs) 1993 - 1997 Pegasus Gold Australia Pty Ltd reported investing more than $200 million in the development of the Mt Todd mine and operated it from 1993 to 1997, when the project closed as a result of technical difficulties and low gold prices. The deed administrators were appointed in 1997 and sold the mine in March 1999 to a joint venture comprised of Multiplex Resources Pty Ltd and General Gold Resources Ltd.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 43 1999 - 2000 March - June Operated by a joint venture comprised of Multiplex Resources Pty Ltd and General Gold Resources Ltd. Operations ceased in July 2000, Pegasus Gold Australia Pty Ltd., through the Deed Administrators, regained possession of various parts of the mine assets in order to recoup the balance of purchase price owed to it. Most of the equipment was sold in June 2001 and removed from the mine. The tailings facility and raw water facilities still remain at the site. 2000 - 2006 The Deed Administrators, Pegasus Gold Australia Pty Ltd, the government of the NT, and the Jawoyn Association Aboriginal Corporation held the property. 2006 March Vista Gold Corp. acquired mineral lease rights from the Deed Administrators. 6.2 Historic Drilling The following discussion centers on the historic drillhole databases that were provided to Tetra Tech for use in this Technical Report. Based on the reports by companies, individuals and other consultants, it is the opinion of the QP [Rex Clair Bryan, Ph.D., SME RM] that the drillhole databases used as the bases of this report contain all of the available data. The QP is unaware of any drillhole data that have been excluded from this report. 6.2.1 Batman Deposit There are 730 historic drillholes in the Batman deposit assay database. Figure 6-1 shows the drillhole locations for the Batman deposit. These drillholes include 225-diamond drill core (DDH), 435 reverse circulation holes (RVC), and 70 open rotary holes (OP). Nearly all of the DDH and RVC holes were inclined 60° to the west. Samples were collected in one-meter intervals. DDH holes included both HQ and NQ core diameters. Core recoveries were reported to be very high with a mean of 98%. The central area of the deposit was extensively core-drilled. Outside of the central area, most of the drillholes were RVC and OP holes. All drillholes collars were surveyed by the mine surveyor. Down-hole surveys were conducted on most drillholes using an Eastman single shot instrument. All drillholes were logged on site. A series of vertical RVC infill holes were drilled on a 25 m x 25 m grid in the core of the deposit to depths between 50 m and 85 m below the surface. Zapopan elected to exclude these drillholes from modeling the Batman deposit because the assays from these drillholes seemed to be downwardly biased and more erratic compared to assays from inclined RVC holes. Of the possible reasons cited as to why vertical RVC holes might report lower grades and have a more erratic character, the 1992 Mining & Resource Technology Pty Ltd (Khosrowshahi et al. 1992 – MRT) report states that "the orientation of vertical holes sub-parallel to mineralization caused preferential sampling of barren host rocks...”. This statement was, at least in part, borne out by the later sampling work done on the blast holes as it was credited with part of the reproducibility problems that were encountered when the Batman deposit was being mined.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 44 6.2.2 Drillhole Density and Orientation Pegasus was aware of the potential problem of drillhole density within the Batman deposit. The feasibility study prepared by BKK (BKK, 1996) indicates that the drilling density decreases with depth. In the central area oxide and transition zone spacing was generally 25 m by 25 m. The spacing was wider on the periphery of the mineralized envelope. The drilling density in the central area of the primary zone ranged from 50 m by 50 m, but decreased to 50 m by 100 m and greater at depth. At the time of that study, there were 593 drillholes in the assay database 531 of which RSG used in the construction of the MRT block model. At the time of The Winters Company’s (TWC) site visit in 1997, the drillhole database numbered 730 drillholes. It is not known if any drillholes were excluded from the Pegasus exploration models. Most of the new drilling that had been added since the 1994 MRT model was relatively shallow. TWC reviewed PGA's 50 m drill sections through the Batman deposit and saw that there was a marked decrease in drillhole spacing below 1,000 RL (the model has had constant 1,000 m added to it in order to prevent the reporting of elevations below 0 m and have been denoted as RL for relative elevation) and another sharp break below 900 RL. The drillhole spacing in the south of 1,000 N on the 954 RL bench plan approached 80 m x 80 m. Pegasus was able to resolve this problem by using very long search ranges in its grade estimation. In the main ore zone, Pegasus used maximum search distances in the north and east directions of nearly 300 m. Another potential problem related to drilling is the preferred orientation of the drillholes. Most of the drillholes in the assay database are inclined to the west to capture the vein set which strikes N10° to 20°E, dips east, and which dominates the mineralized envelope. This orientation is the obvious choice to most geologists since these veins are by far the most abundant. Ormsby (1996) discussed that while the majority of mineralization occurs in these veins, the distribution of gold mineralization higher than 0.4 g-Au/t is controlled by structures in other orientations, such as east-west joints and bedding. For this reason, Ormsby stated, "[t]he result is that few ore boundaries (in the geological model) actually occur in the most common vein orientation." If this is truly the case, the strongly preferential drilling orientation has not crosscut the best mineralization and in cases may be sub-parallel to it. Vertically oriented RVC holes were not included in the drillhole database for the 1994 MRT model because their assay results appeared to be too low compared to other drillhole orientations. If vertical drillhole orientations were actually underestimating the gold content during exploration drilling, the vertical and often wet blast holes, which are used for ore control, pose a similar problem and will need to be addressed prior to commencing any new mining on the site.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 45 6.2.3 Quigleys Table 6-3 details the Quigleys exploration database as of the time of this report. Figure 6-1 also shows the drillhole locations for the Quigleys deposit. Table 6-3: Summary of Quigleys Exploration Database Drillhole Statistics Northing (m) AMG84 z53 Easting (m) AMG84 z53 Elevation (m) Azimuth Dip Depth (m) Minimum 8,430,1876 188,445.7 129.7 0 45 0 Maximum 8,432,290 189,746.5 209.0 354.0 90 330.5 Average 8,431,129.5 189,230.8 155.9 83.4 62.5 91.3 Range 2,104.0 1,300.8 79.3 354.0 45.0 330.5 Cumulative Drillhole Statistics Total Count 631 Total Length (m) 57,821 Assay Length (m) 1 (approx.) Drillhole Grade Statistics Number Average Std. Dev. Min. Max. Missing Au (g/t) 52,152 0.2445 0.8764 0 36.00 82 Cu (%) 40,437 0.0105 0.0305 0 2.98 11,897 The QP [Rex Clair Bryan, Ph.D., SME RM] for this section has reviewed the Snowden (1990) report which completed a statistical study of the Quigleys drillhole database in order to bias test it. The report included a comparison of historic and recent data by Snowden which suggested that a bias might exist. Further study by Snowden concluded that a bias is not apparent where all drilling is oriented in a similar direction (and not clustered). This suggests the inclusion of assay data from all phases of drilling is reasonable. The QP [Rex Clair Bryan, Ph.D., SME RM] has reviewed and concurs with this information. The March 14, 2008 report entitled “Mt Todd Gold Project, Gold Resource Update, Northern Territory, Australia, NI 43-101 Technical Report” prepared by John W. Rozelle contains additional information regarding the Snowden findings summarized above.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 46 Figure 6-1: Drillhole Location Map – Batman and Quigleys Deposits

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 47 6.3 Historic Sampling Method and Approach NQ core intervals were sawed lengthwise into half core. HQ core was quartered. RVC samples were riffle split on site and a 3- to 4-kg sample was sent to an assay lab. The 1992 MRT resource report commented that many of the RVC holes were drilled wet and that Billiton and Zapopan were aware of possible contamination problems. Oddly, in some comparison tests, DDH had averaged assays five percent to six percent higher than RVC holes; for that reason, MRT elected to exclude RVC holes from the drillhole database for grade estimation of the central area of the Batman deposit. Since the property is currently not operating, the QP [Rex Clair Bryan, Ph.D., SME RM] did not witness any drilling and sampling personally. The QP has taken the following discussion from reports by the various operators and more importantly, from reports by independent consultants that were retained throughout the history of the property to audit and verify the sampling and assaying procedures. It is the opinion of the QP for this section that the reports by the various companies and consultants have fairly represented the sampling and assaying history at the site and that the procedures implemented by the operators, most notably General Gold, have resulted in an assay database that fairly represents the tenor of the mineralization at Batman. 6.4 Historic Sample Preparation, Analysis and Security The large number of campaigns and labs used in the Mt Todd drilling effort has resulted in a relatively complex sampling and assaying history. The database developed prior to August of 1992 was subjected to a review by Billiton, and has been subjected to extensive check assays throughout the project life. Furthermore, a number of consultants have reviewed the integrity of the database and have been content with the data for modeling purposes. Drillhole samples were taken on one-meter intervals, though there are instances of two-meter intervals in the typically barren outlying drillholes. The procedure involved sawing the NQ core lengthwise in half. HQ core was quartered. RVC samples were riffle split on site and a 3- to 4-kg sample was sent to the laboratory for analyses. Pincock Allen and Holt (PAH) stated that they witnessed the sample preparation process at a number of steps and concurred with the methods in use (PAH, 1995). Pegasus (and Zapopan, before) conducted a check assay program which is consistent with industry practice. Every 20th assay sample was subjected to assay by an independent lab. Standards were run periodically as well, using a non-coded sample number to prevent inadvertent bias in the labs. 6.4.1 Sample Analysis According to reports by Pegasus, various consultants, and others, the early exploration assays were largely done at various commercial labs in Pine Creek Geosyncline (PCG) and Darwin. Later assays were done at the Mt Todd mine site lab. At least three different sample preparation procedures were used at one time or another. All fire assays were conducted on 50-gram charges. Based on these reports, it appears that the assay labs did use their own internal assay blanks, standards, and blind duplicates. Assay laboratories used for gold analysis of the Batman drill data were Classic Comlabs in Darwin, Australia, Assay Laboratories in Pine Creek and Alice Springs and Pegasus site Laboratory.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 48 The exploration data consist of 91,225 samples with an average and median length of 1 m. The minimum sample length is 0.1 m and the maximum sample length is 5 m. 137 samples are less than 1 m and 65 samples are over 1 m in length. All exploration drill data were used for the resource estimate. Four-meter down hole composite samples were calculated down hole for the resource estimate. The assay composited data were tabulated in the database field called “Comp”. The weighted average grades, the length, and the drillhole were recorded. 6.4.2 Check Assays Extensive check assaying was carried out on the exploration data. Approximately 5% of all RVC rejects were sent as duplicates and duplicate pulps were analyzed for 2.5% of all DDH intervals. Duplicate halves of 130 core intervals were analyzed as well. Overall, Mt Todd's check assay work is systematic and acceptable. The feasibility study showed that the precision of field duplicates of RVC samples is poor and that high errors exist in the database. The 1995 study stressed that because of the problems with the RVC assays, the RVC and OP assays should be kept in a separate database from the DDH assays (PAH, 1995). However, since that time, the majority of the identified assaying issues have been corrected by General Gold based on recommendations of consultants. It is the opinion of the QP responsible for this section that the assay database used in the creation of the current independent resource estimation exercise is acceptable and meets industry standards for accuracy and reliability. 6.4.3 Security The QP responsible for this section is unaware of any “special” or additional security measures that were in place and/or followed by the various exploration companies, other than the normal practices of retaining photographs, core splits, and/or pulps of the samples sent to a commercial assay laboratory. 6.5 Historic Process Description The Mt Todd deposit is a large, but low-grade gold deposit. The average grade of the gold mineralization is approximately 1 g-Au/t. The gold mineralization occurs in a hard, uniform greywacke host and is associated with sulfide and silica mineralization which has resulted from deposition along planes of weakness that had opened in the host rock. Gold is very fine grained (<30 microns) and occurs with both silica and sulfides. The host rock is very competent with a Bond Ball Mill Work Index (BWi) of 23 to 30. Pegasus and earlier owners did extensive metallurgical testing from 1988 to 1995 to develop a process flowsheet for recovering gold from low-grade extremely hard rock. The treatment route, based on the metallurgical studies, was engineered to provide for the recovery of a sulfide flotation concentrate which was subsequently reground and leached in a concentrate leach circuit. Flotation tailings were leached in a separate CIL circuit. The historic design process flowsheet for the Project is given in Figure 6-2. A brief description of the major unit operations is as follows: „ Crushing: Four stages of crushing were employed to produce a product having a P80 of 2.6mm. The primary crusher was a gyratory followed by secondary cone crushers in closed circuit. Barmac vertical shaft impact crushers were used for tertiary crushing in closed circuit and

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 49 quaternary crushing stages. The crushed product was stored under a covered fine ore stockpile. „ Grinding: The crushed product was drawn from the fine ore stockpile into three parallel grinding circuits, each consisting of an overflow ball mill in closed circuit with cyclones to produce a grind with a P80 of 150 microns. „ Flotation: Cyclone overflow was sent to the flotation circuit where a bulk concentrate was supposed to recover seven percent of the feed with 65% to 70% of the gold. „ CIL of Tailing: The flotation tailing was leached in carbon-in-leach circuit. The leach residue was sent to the tailings pond. Approximately 60% of the gold in the flotation tailings was supposed to be recovered in the CIL circuit. „ CIL of Flotation Concentrate: The flotation concentrate was reground in Tower mills to 15 microns and subjected to cyanide leaching to recover the bulk of the gold in this product (94.5% of the flotation concentrate). The leach residue was sent to the tailings pond. „ Process Recycle: The process water was recycled to the milling circuit from the tailings pond. The overall gold recovery was projected to be 83.8% for the proposed circuit. However, during the initial phase of plant optimization, problems were encountered with high levels of cyanide in the recycled process water which, when returned to the mill, caused depression of pyrite and much lower recoveries to the flotation concentrate. As a result, the flotation plant was shut down and the ground ore was directly sent to the CIL circuit. The modified process flowsheet is given in Figure 6-3. „ Without the flotation circuit, the CIL plant recovered 72 to 75% of the gold. The plant was shut down and placed on care and maintenance within one year of startup due to a collapse in gold price, under performance of the process plant and higher than projected operating costs. 6.6 Technical Problems with Historical Process Flowsheet There were several technical problems associated with the design flowsheet. These technical problems have been documented by plant engineers, TWC, and other investigators. They are briefly discussed in this section. 6.6.1 Crushing The four-stage crushing circuit was supposed to produce a product with P80 of 2.6mm. Also, historically the tonnage was projected to be 8 Mtpy on an annualized basis. The actual product achieved in the plant had a P80 of 3.2 to 3.5 mm and the circuit could handle a maximum of 7 Mtpy on an annualized basis. This resulted in an increased operating cost for gold production. A four-stage crushing/ball mill circuit was selected over a SAG/ball mill/crusher circuit because crushers were available from the Phase I heap leach pad and could be used in the Phase II program. The use of this available equipment did reduce the overall capital cost.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 50 Figure 6-2: Plant Process Flowsheet for Project as Designed

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 51 Figure 6-3: Modified Plant Process Flowsheet for Project

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 52 The following problems were encountered with the crushing circuit: „ The mechanical availability of the Barmac vertical shaft impact crushers was extremely poor. „ The Barmac crushers were not necessarily the best choice for the application. The three-stage crusher product could have been sent to the mills which would have had to have been larger size mills. „ The crushing circuit generated extreme amounts of fines and created environmental problems. The dust also carried gold with it. The dust levels increased the wear on machinery parts and were a potential long-term health hazard. „ The use of water spray to keep the dust down resulted in use of large amounts of fresh water. This was a strain on the availability of fresh water for the plant. General Gold operated a whole-ore cyanide leach facility but no technical reports describing their process have been located by Vista to date. 6.6.2 Flotation Circuit The flotation circuit was supposed to recover 60 to 70% of the gold in a bulk sulfide concentrate which was 7% of the feed material. The flotation circuit recovered ± 1% of the weight of material and less than 50% of the gold values. This was due to the significant amount of cyanide in the recycle process water which depressed the sulfide minerals in the flotation process. If the process water had been detoxified, the problems would not have occurred. This was not done because of the cost associated with a cyanide detoxification plant. Additional problems which were overlooked during the testwork and design of the plant included the following: „ The presence of cyanide soluble copper was known but was not taken into consideration during the design of the process flowsheet; and „ Removal of copper from the bulk sulfide in the form of a copper concentrate would have reduced the consumption of cyanide as well as the amount of weak acid dissociable (WAD) cyanide in the recycled process water. Pilot plant testing was undertaken in the plant to produce copper concentrate. Documented results do indicate ± 60% of copper recovery at a concentrate grade of +10% Cu. Approximately 45% of the gold reported to this concentrate. However, from Vista’s discussions with the engineering contractors and the Pegasus staff running the pilot plant, a copper concentrate assaying over 20% was achieved in some of the later tests. 6.6.3 CIL of Flotation Concentrate and Tailings A portion of the copper was depressed with cyanide with the recycled process water in the flotation process. Hence, the cyanide consumption was high even in the leaching of the flotation tailings. The availability of dissolved oxygen in leaching terms was very low thereby resulting in poor extraction of gold in the leach circuit. This resulted in an estimated reduction of 40% of gold recovery in the circuit.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 53 7.0 GEOLOGICAL SETTING AND MINERALIZATION 7.1 Geological and Structural Setting The Project is situated within the southeastern portion of the Early Proterozoic Pine Creek Geosyncline (Figure 7-1). Meta-sediments, granitoids, basic intrusives, acid and intermediate volcanic rocks occur within this geological province. Within the Mt Todd region, the oldest outcropping rocks are assigned to the Burrell Creek Formation. These rocks consist primarily of interbedded greywackes, siltstones, and shales of turbidite affinity, which are interspersed with minor volcanics. The sedimentary sequence incorporates slump structures, flute casts and graded beds, as well as occasional crossbeds. The Burrell Creek Formation is overlain by interbedded greywackes, mudstones, tuffs, minor conglomerates, mafic to intermediate volcanics and banded ironstone of the Tollis Formation. The Burrell Creek Formation and Tollis Formation comprise the Finniss River Group. The Finniss River Group strata have been folded about northerly trending F1 fold axes. The folds are closed to open style and have moderately westerly dipping axial planes with some sections being overturned. A later north-south compression event resulted in east-west trending open style upright D2 folds. The Finniss River Group has been regionally metamorphosed to lower green schist facies. Late and Post Orogenic granitoid intrusion of the Cullen Batholith occurred from 1,789 Ma to 1,730 Ma, and brought about local contact metamorphism to hornblende hornfels facies. Unconformably overlying the Burrell Creek Formation are sandstones, shales and tuffaceous sediments of the Phillips Creek sandstone, with acid and minor basic volcanics of the Plum Tree Creek Volcanics. Both these units form part of the Edith River Group, and occur to the south of the Project Area. Relatively flat lying and undeformed sediments of the Lower Proterozoic Katherine River Group unconformably overlie the older rock units. The basal Kombolgie Formation forms a major escarpment, which dominates the topography to the east of the Project area.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 54 7.2 Local Geology The geology of the Batman deposit consists of a sequence of hornfelsed interbedded greywackes, and shales with minor thin beds of felsic tuff. Bedding is striking consistently at 325°, dipping at 40° to 60° to the southwest. Minor lamprophyre dykes trending north-south pinch and swell, cross cutting the bedding. Nineteen lithological units have been identified within the deposit and are listed in Table 7-1 below from south to north (oldest to youngest). Table 7-1: Geologic Codes and Lithologic Units Unit Code Lithology Description 1 GW25 Greywacke 2 SH24 Shale 3 GW24A Greywacke 4 SHGW24A shale/greywacke 5 GW24 Greywacke 6 SHGW23 shale/greywacke 7 GWSH23 greywacke/shale 8 GW23 Greywacke 9 SH22 Shale 10 T21 felsic tuff 11 SH21 Shale 12 T20 felsic tuff 13 SH20 Shale 14 GWSH20 greywacke/shale 15 SH19 Shale 16 T18 felsic tuff 17 SH18 Shale 18 GW18 Greywacke Int INT lamprophyre dyke Bedding parallel shears are present in some of the shale horizons (especially in units SHGW23, GWSH23 and SH22). These bedding shears are identified by quartz/ calcite sulfidic breccias. Pyrite, pyrrhotite, chalcopyrite, galena and sphalerite are the main primary sulfides associated with the bedding parallel shears. East west trending faults and joint sets crosscut bedding. Only minor movement has been observed on these faults. Calcite veining is sometimes associated with these faults. These structures appear to be post mineralization.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 55 Northerly trending quartz sulfide veins and joints striking at 0° to 20°, dipping to the east at 60° are the major location for mineralization in the Batman deposit. The veins are 1 millimeter (mm) to 100 mm in thickness with an average thickness of around 8 mm to 10 mm. The veins consist of dominantly quartz with sulfides on the margins. The veining occurs in sheets with up to 20 veins per horizontal m. These sheet veins are the main source of mineralization in the Batman deposit.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 56 Figure 7-1: General Geologic Map

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 57 7.3 Mineralization A variety of mineralization styles occur within the Mt Todd area. Of greatest known economic significance are auriferous quartz-sulfide vein systems. These vein systems include the Batman, Jones, Golf, Quigleys and Horseshoe prospects, which occur within a north-northeast trending corridor, and are hosted by the Burrell Creek Formation. Tin occurs in a north-northwest trending corridor. The tin mineralization comprises cassiterite, quartz, tourmaline, kaolin, and hematite bearing assemblages, which occur as bedding to parallel breccia zones and pipes. Polymetallic Au, W, Mo, and Cu mineralization occurs in quartz-greisen veins within the Yinberrie Leucogranite; a late stage highly fractionated phase of the Cullen Batholith. The Batman Deposit extends approximately 2,200 m along strike, 400 m across dip and drill tested to a depth of 800 m. Drilling indicates the Batman mineralization to be open along-strike and down-dip. 7.3.1 Batman Deposit 7.3.1.1 Local Mineralization Controls The mineralization within the Batman deposit is directly related to the intensity of the north-south trending quartz sulfide veining. The lithological units impact on the orientation and intensity of mineralization. Sulfide minerals associated with the gold mineralization are pyrite, pyrrhotite and lesser amounts of chalcopyrite, bismuthinite and arsenopyrite. Galena and sphalerite are also present, but appear to be post- gold mineralization, and are related to calcite veining in the bedding plains and the east-west trending faults and joints. Two main styles of mineralization have been identified in the Batman deposit. These are the north-south trending vein mineralization and bedding parallel mineralization. 7.3.1.2 North-South Trending Corridor The north-south trending mineralization occurs in all rock units and is most dominant in the shales and greywackes designated SHGW23. Inspection of grade control and exploration data, drill logs, diamond core and the pit has shown that the north-south trending mineralization can be divided into three major zones based on veining and jointing intensity. CORE COMPLEX Mineralization is consistent and most, to all, joints have been filled with quartz and sulfides. Vein frequency per meter is high in this zone. This zone occurs in all rock types. HANGING WALL ZONE Mineralization is patchier than the core complex due to quartz veining not being as abundant as the core complex. The lithology controls the amount of mineralization within the hanging wall zone. The hanging wall zone doesn’t occur north of T21. South of reference line T21 to the greywacke shale unit designated GWSH23, the mineralization has a bedding trend. A large quartz/pyrrhotite vein defines the boundary of the hanging wall and core complex in places.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 58 FOOTWALL ZONE Like the hanging wall zone, the mineralization is patchier than the core complex and jointing is more prevalent than quartz veining. Footwall Zone mineralization style is controlled by the lithology and occurs in all lithological units. Narrow bands of north-south trending mineralization also occur outside the three zones, but these bands are patchy. BEDDING PARALLEL MINERALIZATION Bedding parallel mineralization occurs in rock types SH22 to SH20 to the east of the Core complex. Veining is both bedding parallel and north south trending. The mineralization appears to have migrated from the south along narrow north-south trending zones and “balloon out” parallel to bedding around the felsic tuffs. 7.3.2 Quigleys Deposit The Quigleys deposit mineralization was interpreted by Pegasus and confirmed by Snowden (1990) to have a distinctive high-grade shallow dipping 30°-35° northwest shear zone extending for nearly 1 km in strike and 230 m vertical depth within a zone of more erratic lower grade mineralization. The area has been investigated by RVC and diamond drilling by Pegasus and previous explorers on 50 m lines with some infill to 25 m. The QP [Rex Clair Bryan, Ph.D., SME RM] has reviewed and concurs with this information. Drillhole intersections generally revealed an abrupt change from less than 0.4 g-Au/t to high grade (>1 g-Au/t) mineralization at the hanging wall position of the logged shear, but also revealed a gradational change to lower grade mineralization with depth. Some adjacent drillholes were also noted with significant variation in the interpreted position of the shear zone, and some of the discrepancies appeared to have been resolved on the basis of selection of the highest gold grade. While the above method may result in a valid starting point for geological interpretation, the selection of such a narrow high grade zone is overly restrictive for interpretation of mineralization continuity and will require additional work prior to estimating any resources. It was further thought that while the shear might be readily identified in diamond drillholes, interpretation in RVC drilling, and in particular later interpretation from previously omitted RVC holes, must invoke a degree of uncertainty in the interpretation. The QP [Rex Clair Bryan, Ph.D., SME RM] agrees with the conclusion of the Snowden report that while the shear zone was identifiable on a broad scale, the local variation was difficult to map with confidence and therefore difficult to estimate with any degree of certainty at this time. It is for these reasons that Vista has only drilled diamond drillholes. As reference above, the shears and other structural features are identifiable in drill core.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 59 NOTE: Prepared by Vista Gold Corp.; updated on February 23, 2018 Figure 7-2: Concessions

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 60 8.0 DEPOSIT TYPES According to Hein (2003), the Batman and Quigleys gold deposits of the Mt Todd Mine are formed by hydrothermal activity, concomitant with retrograde contact metamorphism and associated deformation, during cooling and crystallization of the Tennysons Leucogranite and early in D2 (Hein, submitted for publication). It is speculated that pluton cooling resulted in the development of effective tensile stresses that dilated and/or reactivated structures generated during pluton emplacement and/ or during D1 (Furlong et al., 1991, as cited in Hein, 2003), or which fractured the country rock carapace as is typical during cooling of shallowly emplaced plutons (Knapp and Norton, 1981, as cited in Hein, 2003). In particular, this model invokes sinistral reactivation of a northeasterly trending channelization basement strike–slip fault, causing brittle failure in the upper crust and/or dilation of existing north–northeasterly trending faults, fractures, and joints in competent rock units such as meta-greywackes and siltstones. The generation of dilatant structures above the basement structure (i.e., along a northeasterly trending corridor overlying the basement fault), coupled with a sudden reduction in pressure, and concomitant to brecciation by hydraulic implosion (Sibson, 1987; Je´brak, 1997; both as cited in Hein, 2003) may have facilitated channelization of predominantly metamorphic fluid in the intermediate contact metamorphic aureole (possibly suprahydrostatic-pressured) and into the upper crust (Furlong et al., 1991; Cox et al., 2001; both as cited in Hein, 2003). Rising fluids decompressed concurrent with mineral precipitation. Throttling of the conduit or fluid pathways probably resulted in over pressuring of the fluid (Sibson, 2001, as cited in Hein, 2003), this giving way to further fracturing, etc. Mineral precipitation accompanied a decrease in temperature although, ultimately, the hydrothermal system cooled as isotherms collapsed about the cooling pluton (Knapp and Norton, 1981). Gold mineralization is constrained to a single mineralizing event that included: „ Retrogressive contact metamorphism during cooling and crystallization of the Tennysons Leucogranite; „ Fracturing of the country rock carapace; „ Sinistral reactivation of a NE-trending basement strike-slip fault; „ Brittle failure and fluid-assisted brecciation; and „ Channelization of predominantly metamorphic fluid in the intermediate contact metamorphic aureole into dilatant structures. The deposits are similar to other gold deposits of the porphyry copper gold (PCG) and are classified as orogenic gold deposits in the subdivision of thermal aureole gold style. The Batman deposit shares some characteristics with intrusion-related gold systems, especially in terms of the association of gold with bismuth and reduced ore mineralogies. This makes the deposit unique in the PCG. The mineral deposit types being investigated and the geological model being applied are described in Section 9.0 – Exploration and Section 14.0 – Mineral Resource Estimates, respectively.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 61 9.0 EXPLORATION Since acquiring the Mt Todd mining leases and exploration licenses, Vista has conducted an ongoing exploration program that includes prospecting, geologic mapping, rock and soil sampling, geophysical surveys and exploration drilling. Equipment and personnel were mobilized from the Mt Todd Mine site or from an exploration base camp established in the central part of the exploration licenses. The work was conducted by geologists and field technicians. The exploration effort initially focused on follow up work on targets developed by Pegasus during their tenure on the property. These included the RKD target, Tablelands, and Silver Spray. During a review of Pegasus’ airborne geophysical survey data, five distinct magnetic highs were observed located within sedimentary rocks that should have a low magnetic signature. These features are remarkably similar to those at the Batman deposit, which, as a result of the included pyrrhotite, exhibits a strong magnetic high. The geophysical targets were prioritized following review of historic work in the area and site visits. To date, two of the geophysical targets (Golden Eye and Snowdrop) have been grilled and a third has been covered by soil sampling (Black Hill). Table 9-1 details soil geochemical samples collected on the exploration licenses (ELs) by year. Table 9-1: Exploration Sampling Before 2018 Year Soil Samples Collected Rock Chip Samples Collected 2008 0 164 2009 1,333 45 2010 3,135 224 2011 1,925 79 2012 2,312 295 2013 572 51 2014 2,601 143 2015 841 53 2016 241 27 2017 1,098 78 Total Samples 14,058 1,211

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 62 Within the same ELs, Vista Gold obtained 654 soil samples and 222 rock-chip samples in an exploration program between March 2, 2018 and October 7, 2019. Table 9-3 lists the type, sample count and general location. Table 9-2: Exploration Sampling Between 2018 and 2019 by Target Area Type Start Date End Date Location Count Soil 14/07/2018 28/07/2018 Wandie Creek NW infill 231 Soil 27/07/2018 29/07/2018 SW of Crest of the Wave 109 Soil 01/01/2019 3/1/2019 Batman North 77 Soil 10/02/2019 5/10/2019 Blue Sage 237 Total Soil 14/07/2018 5/10/2019 All Soil Areas 654 Rock Chip 2/3/2019 7/10/2019 Multiple Tenements 222 Total Chip 2/3/2019 7/10/2019 All Rock Chip 222 Table 9-3: Exploration Prospects Year Drill Hole Location Zone GDA94 Coords Tasks Completed Prospect Lease No Easting Northing RL Depth Rehab Status 2010 GE10-001 Goldeneye EL29886 53L 200220 8455415 184 252 Closed GE10-002 Goldeneye EL29886 53L 200360 8455415 178 297 Closed GE10-003 Goldeneye EL29886 53L 200340 8455495 189 194 Closed GE10-004 Goldeneye EL29886 53L 200190 8455495 189 194 Closed RKD10-001 RKD EL29882 53L 197400 8450650 201 201 Closed RKD10-002 RKD EL29882 53L 197440 8450550 225 225 Closed RKD10-003 RKD EL29882 53L 197440 8450550 291 291 Closed RKD10-004 RKD EL29882 53L 197400 8450520 336 336 Closed RKD10-005 RKD EL29882 53L 197530 8450450 183 183 Closed RKD10-006 RKD EL29882 53L 197360 8450490 552 352 Closed 2011 SS11-001 Silver Spray EL29882 53L 208572 8460026 217 369 Closed SS11-002 Silver Spray EL29882 53L 208607 8459933 211 438 Closed LL11-001 Limestone Quarry EL28321 52L 813950 8426350 95 60 Closed LL11-002 Limestone Quarry EL28321 52L 813950 8426300 95 60 Closed LL11-003 Limestone Quarry EL28321 52L 813950 8426250 95 60 Closed LL11-004 Limestone Quarry EL28321 52L 814050 8426350 95 64 Closed LL11-005 Limestone Quarry EL28321 52L 814050 8426300 95 61 Closed LL11-006 Limestone Quarry EL28321 52L 814050 8426250 95 60 Closed

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 63 Year Drill Hole Location Zone GDA94 Coords Tasks Completed Prospect Lease No Easting Northing RL Depth Rehab Status GE11-001 Goldeneye EL29886 53L 200300 8455555 177 195 Closed GE11-002 Goldeneye EL29886 53L 200240 8455455 182 351 Closed GE11-003 Goldeneye EL29886 53L 200350 8455455 182 241 Closed GE11-004 Goldeneye EL29886 53L 200400 8455500 186 267 Closed GE11-005 Goldeneye EL29886 53L 200400 8455555 186 240 Closed 2012 SD12-001 Snowdrop EL29882 53L 195169 8457484 171 219 Closed 2015 SD15-001 Snowdrop EL29882 53L 195164 8457302 170 250 Closed SD15-002 Snowdrop EL29882 53L 195142 8457248 170 250 Closed SD15-003 Snowdrop EL29882 53L 195305 8457599 170 250 Closed WD15-001 Wandie EL29882 53L 190947 8455709 169 46 Closed WD15-002 Wandie EL29883 53L 190920 8455696 168 100 Closed WD15-003 Wandie EL29884 53L 190890 8455679 167 135 Closed 2016 WD16-001 Wandie EL29882 53L 190859 8455663 166 204 Closed 6,445 2018 WD18-001 Wandie EL29882 53L 190220 8456760 148 279.5 Open WD18-002 Wandie EL29882 53L 190275 8456640 149 291.4 Open 7,016 9.1 Golden Eye Target At Golden Eye, an initial 100m x 100m soil program identified 2 anomalous samples, one of 70PPB and one of 50ppb, follow-up rock chip sampling, in an area with limited exposure, returned a 25.0 g-Au/t sample from a small outcrop of Laminated Fe rich sediments. Further sampling returned 23.0 g-Au/t and 7.7 g-Au/t assays in vein and breccias located 15 m and 50 m, respectively, north of the original sample. Due to the sparse outcrop, the orientation and thickness of the mineralized zone is not currently known. An infill soil sampling program over the area was completed on a 20 m grid. The survey returned a strong coherent gold anomaly approximately 400 m in diameter with coincident anomalous base metals and arsenic. In 2010 Vista completed four drillholes on the target. All four drillholes intersected strong sulfide mineralization associated with laminated Fe rich Burrell Creek Formation with interesting concentrations of copper, lead zinc and anomalous gold mineralization, with the best intercept occurring in drillhole GE10-003 and consisting of 1.1 m of 7.69 g-Au/t including 0.3 m of 26.7 g-Au/t. Five additional drillholes were completed during the 2011 field season. Drilling intersected several narrow weakly mineralized zones; however, none that can yet be correlated with any confidence between different

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 64 drillholes or between the drillholes and the mineralization identified on the surface. The most encouraging mineralization was intersected by GE11-002, consisting of a sheared, chloritic and broken sulfide-rich unit from 54.2 m to 55 m which assayed 1.41 g-Au/t and a siliceous lode from 162.07m to 162.82 m which assayed 1.86 g-Au/t. The remaining drillholes all intersected widespread quartz sulfide veining containing pyrrhotite, chalcopyrite, and arsenopyrite and contained anomalous gold, copper, bismuth, and arsenic. Although thin and patchy, this mineralization is at least a clear indication that there is a mineralized system at Golden Eye which is yet to be defined with confidence. A detailed ground magnetic survey was completed over the area in 2012 and an airborne UTS geophysical survey was conducted in 2013. One IP line was conducted in 2017 to determine if a more extensive program would be helpful, this defined a thin target zone. The survey results, combined with detailed mapping and the drillhole data, have been reviewed and additional drilling is recommended. 9.2 RKD Target Six drillholes totaling 1,587.4 m were completed on the target known as RKD during 2011. The drillholes intersected a NNW trending mineralized shear zone dipping steeply to the west. The best gold intercept was in drillhole RKD11-003 which contained 2.7 m of 2.3 g-Au/t. Drillhole RKD11-005 intersected 3 m of 3.4% copper and 50 ppm silver a chalcocite-rich part of the shear zone. All of the drillholes intersected anomalous gold with values up to 0.4 and 0.5 g-Au/t. Extensive surface mapping and rock-chip sampling indicates that RKD is likely to be thin and is strike constrained. 9.3 Silver Spray Target Two drillholes totaling 806.8 m were completed at Silver Spray. The drillholes intersected strong chloritic alteration throughout both drillholes. Both drillholes intersected several 20-m zones of strong quartz veining with a thin (30 cm) zone of galena, pyrrhotite and arsenopyrite. These zones contained anomalous lead, zinc, and arsenic but only sporadic anomalous gold (up to 0.18 g-Au/t). 9.4 Snowdrop Target In 2011, 100m x 100m soil geochemical lines were completed across the Snowdrop magnetic anomaly. These soils were later closed in on a 20-m spacing. The results confirmed and refined the gold-copper-arsenic- bismuth anomaly with 146 samples of 481 samples containing 100 ppm or greater copper and 60 samples containing greater than 5 ppb gold (high value 97 ppb). The onset of the wet season has suspended work on the target until next spring. A drill plan will be included in the updated mine management plan to permit drilling in 2012. In 2012, the detailed 20 m by 20 m infill soil sampling program was continued. A total of 3,376 soils have been collected in the target area. Results show a coherent gold anomaly that is 200-m wide and at least 700-m long. It is oriented NE-SW and flanks a strong magnetic high. There is a strong correlation with As, Bi and Fe with zoned Cu and Zn on the margins. Rock chip sampling in the area has identified the highest grades within gossanous rocks associated with quartz float. Rock chip samples range up to 6 ppm. In late November, 2012, a single diamond drillhole was completed on the target before the onset of the wet season. SD12-01 was drilled at an angle across the target zone to a depth of 219.1m. The drillhole intersected zones of intensely silicified greywackes and shales with minor sheeted quartz veins. The alteration and

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 65 veining is notably similar to that observed at the Batman deposit in the vicinity of the core zone. The greywacke units are coarser grained than at Batman, but the frequency of lithological changes and alteration types are all very similar. Sulfides are present within the quartz veining and as disseminated blebs within intensely silicified siltstones. Common sulfide minerals include pyrite, pyrrhotite, chalcopyrite, and arsenopyrite with traces of galena, sphalerite and bornite. Veining has a steep dip to the east, similar to Batman, but appears richer in base metals. Disseminated sulfides are also more abundant, while the vein density is not as intense as Batman. Although the drillhole did not intersect significant ore grade mineralization, assay results were encouraging and additional drilling is warranted. The highest grade intercept was 0.90 g-Au/t with six intervals returning greater than 0.4 g-Au/t. In total, 80 intervals out of 272 samples contained detectable gold with two intervals greater than 30 m containing detectable gold. Two geochemical signatures are apparent in the assay data; one with gold associated with anomalous base metals and one with an association with As, Bi, Co, and Te. To date, this early-stage exploration program has not produced an announceable discovery on the ELs. While the work is promising and will be ongoing, there are no quantifiable resources or reserves. Once an announceable discovery is made, Vista will detail that discovery according to all applicable disclosure regulations. 9.5 Sample Preparation Methods and Quality Control (QC) Measures Soil samples were planned on a regular grid and a sample sheet is generated, GPS is used to locate sample positions and a pelican pick is used to clear debris and any topsoil from the sample location, hole is dug to the B horizon and 7 to 10 kg of soil is collected and coarse sieved to remove stones etc., a fine mesh is then employed and the entire sample recovered post sieving is bagged. Soil sampling is usually undertaken in the dry season, however if wet samples are obtained, they are dried in the logging shed prior to sieving. Sample bags are calico and purchased pre-numbered, these are then place 5 each in green plastic bags for transportation to the Assay lab. As the site is closed to public access, no special security measures are undertaken. A sample submission sheet is sent to the lab, detailing required methodology, and number of samples. There is no identifying data relating to sample location on the bags submitted or the paperwork beyond bag numbers. It is the author’s opinion that the sample preparation methods and quality control measures employed before dispatch of samples to an analytical or testing laboratory ensured the validity and integrity of samples taken. 9.6 Relevant Information Regarding Sample Preparation, Assaying, and Analytical Procedures Repeat samples and standards are employed in soil sampling programs, with blind repeats being the most effective, as standards are easily distinguishable from raw samples by the lab. The lab conducts its own QA/QC of which it provides the data to Vista Gold. All sample preparation and analytical work is performed at North Australia Assay laboratories, in Pine Creek MLN, 792 Eleanor Rd, Pine Creek NT 0847. The laboratory is owned and managed by Ray Wooldridge (MRACI, FAusIMM) who has 40+ years’ experience in mineral Chemistry. Anomalous samples are re-assayed at the lab with up to 5 repeats being performed if repeatability is poor. The soil samples are retained onsite bagged and placed in bulk container bins and forklifted onto a site vehicle for transport to the lab, the samples are removed and run as a batch at the lab. Low-level assay work is conducted exclusively to minimize the chance of contamination.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 66 Relevant QA/QC standards were applied to the soil sampling that is utilized as a tool to determine the geographical extent and magnitude of possible mineralization. Typically a 100m x 100m grid is sampled over a broad target, with 20m x 20 m infill spacing being used as follow-up, or to better define the extent of any anomalism identified. Duplicate field samples are undertaken and highly anomalous field samples are investigated by the geologist and may be repeat sampled. The soils database has been designed to allow the date, batch number and associated repeats to be queried direct from database. This is an enhancement to the previous methodology of using an excel spreadsheet, which lends itself to copy/paste errors and makes analysis and reporting of QA/QC on the soils difficult. It is recommended by the author that soils, rock- chip and drill core assaying performed in the future to be subject to a monthly review with standardized reporting forms for QA/QC. This will ensure that any problems are identified rapidly as opposed to during the project analysis phase. Security onsite and at the lab is currently adequate but it is recommended that lockable sample transport boxes be employed in the same manner as drill core. The QP [Rex Clair Bryan, Ph.D., SME RM] is of the opinion that the preparation, analytical, and security procedures followed for the samples are sufficient and reliable for the purpose of exploring for potential drilling targets. The QP is of the opinion that these samples are representative and no factors were identified that would result in sample bias.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 67 10.0 DRILLING See also the historical drilling section (Section 6.2) for additional information on the 730 drillholes from various drilling campaigns before Vista from 1988 to 2007. Section 10.1 summarizes Batman drilling from 1988 to 2017. Section 10.2 focuses on the Vista drilling at Batman from 2012 to 2017. Since 2017, the only drilling completed at Mt Todd has been metallurgical sample collection drilling and not exploration drilling. The QP [Rex Clair Bryan, Ph.D., SME RM] has reviewed the methodology and results of drilling and sampling, statistically tested the approach, confirmed quality control procedures employed and quality assurance actions taken for the Project, and is of the opinion that the data accurately represent the nature and extent of the deposit. 10.1 Summary History of Batman Drilling 1988-2017 Table 10-1 shows a summary of Batman drilling from 1988 to 2017. Note that a large percentage of the historical drilling was by reverse circulation (RC) of less than 100 meters in depth. That RC drilling was used for ore grade control during the mining operations of Pegasus and General Gold Resources. Vista’s drilling discovered a larger Batman resource by probing deeper with diamond drilling averaging 550 meters in depth. Table 10-1: Batman Deposit Drilling History Date Reference Holes (#) Percussion (m) Diamond (m) RC (m) 1988 Truelove 17 1,475 1989 Kenny, Wegmann, Fuccenecco 133 6,263 8,562 3,065 1990 Wegmann, Fuccenecco, Gibbs 122 5,060 8,072 1991 Billiton 149 501 202 3,090 1992 Zapopan 18 1,375 1,320 1993 Zapopan 16 2,814 1994-1997 Pegasus Gold 170 22,534 1998-2000 General Gold Resources 105 7,436 26,365 2007 Vista 25 9,883 2008 Vista 16 8,938 2010 Vista 12 6,864 2011 Vista 7 4,480 2012 Vista 27 17,439 2015 Vista 5 3,185 2016-2017 Vista 4 1,635 1988-2017 Batman Total 826 8,239 75,059 67,260

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 68 10.1.1 Vista Drilling Detail 2012-2017 Between the fourth quarter of 2012 and the end of the first quarter of 2017, the Vista exploration program at the Batman deposit consisted of 22 diamond core drillholes containing 12,530 m that targeted both infill definitional drilling and step-out drilling. Table 10-2 contains information for the 22 diamond core drillholes completed and the additional metallurgical diamond holes (not used in the resource estimation). Table 10-2: Batman Deposit Drillholes Added for Resource Update Drillhole ID Northing m (MGA94 z53) Easting m (MGA94 z53) Elevation (masl) Bearing (°) Dip (°) Total Depth (m) Drillhole Type VB12-015 8434901.6 187446.7 144.4 268 -55 745.85 Diamond VB12-016 8434703.6 187262.7 147.3 267 -61 713.5 Diamond VB12-017 8435349.1 187391.2 150.8 277 -61 833.28 Diamond VB12-018 8434849.2 187429.9 144.7 270 -56 177 Diamond VB12-019 8434846.9 187429.4 144.8 269 -61 731.8 Diamond VB12-020 8435852.4 187359.6 167.3 272 -67 611.9 Diamond VB12-021 8435954.0 187378.8 149.9 271 -65 602.9 Diamond VB12-022 8434453.4 187179.3 153.3 269 -57 647.9 Diamond VB12-023 8435801.3 187371.0 161.3 265 -60 650.88 Diamond VB12-024 8434482.1 187094.7 149.8 266 -58 460.14 Diamond VB12-025 8435656.2 187344.7 158.6 261 -60 650.63 Diamond VB12-026 8434393.4 187066.8 144.8 270 -59 378.9 Diamond VB12-027 8435717.0 187259.7 169.8 291 -54 434.75 Diamond VB15-001 187431 8434480 147 268.3 -75.812 455.5 Diamond VB15-001W1 187431 8434480 147 268.3 -75.812 831.8 Diamond VB15-001W2 187431 8434480 147 268.3 -75.812 746 Diamond VB15-002 187277 8434703 147.268 266.07 -76.19 446.3 Diamond VB15-002W1 187277 8434703 147.268 266.07 -76.19 705 Diamond VB16-002* 187195 8434849 134.84 328.6 -64 485.7 Metallurgical Diamond VB17-001* 187094 8435292 161.5 184.6 -55 166.6 Metallurgical Diamond VB17-002* 187194 8434848 134.84 330.6 -64 485 Metallurgical Diamond VB17-003* 187091 8435290 161.5 188.2 -55 568.9 Metallurgical Diamond VB17-004* 187332 8435054 147.23 269 -58 509.41 Metallurgical Diamond VB18-001* 187418 8434999 146.84 270 -50 586.5 Metallurgical Diamond VB18-002* 187290 8435184 139 275 -58 409.7 Metallurgical Diamond VB18-003* 187289.5 8435184 139 275 -54 394.9 Metallurgical Diamond NOTE: Metallurgical drillholes are not used in the resource estimation. Table 10-3 lists the complete set of drillholes used in the resource estimation. Figure 10-1 is a plan map that details the locations of all exploration drillholes drilled at the Batman deposit up to and including VB18-003.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 69 Five sectional views are shown in Figure 10-2 through Figure 10-6. Selected sectional views and other relevant results are shown in Section 14. The majority of drilling has been angled so as to be approximately perpendicular to the mineralized core. This orientation more accurately transects the true thickness of the mineralization. The Batman mineralization forms a set of stacked plates that strike to the north and plunges steeply to the east. These mineralized zones have been defined by wireframes which are used to constrain the higher grades for resource estimation shown in Figure 14-2. Early drilling sampled the deposit near the surface allowing for shorter drillhole depths. Exploring the deeper portions of the deposit has required drill collars to be offset to the east with longer drillhole lengths to reach the mineralized zone. Recent Vista drilling in particular has targeted the deeper portions of the Batman deposit requiring the drillhole depths shown in Table 10-2. The positioning of the Vista drillhole collars has been constrained to be outside of the flooded historic mine pit. Most latter drilling has been oriented so as to transect the higher grade mineralized zone While there are random high grade intercepts outside of the core, the majority of higher grade mineralization resides in the core. Table 10-3: Batman Drillhole Details HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH 01-MBP-001 187346.1 8435081.0 146.1 270.61 77.00 95.0 01-MBP-002 187326.1 8435081.0 145.7 270.61 77.00 42.0 01-MBP-003 187303.0 8435082.0 144.4 270.61 77.00 24.0 04-NSL-01 187552.7 8435508.0 140.0 270.61 61.69 191.8 04-NSL-02 187517.5 8435507.0 142.4 270.61 60.00 102.0 04-NSL-03 187491.6 8435504.0 144.2 270.61 60.00 84.0 BD001 187040.6 8435002.0 167.9 270.00 60.00 269.6 BD002 187011.6 8435005.0 176.8 270.00 60.00 270.0 BD003 186986.8 8435007.0 184.5 270.00 60.00 270.0 BD004 186950.7 8435009.0 193.8 270.00 60.00 120.0 BD005 186951.2 8435009.0 194.0 277.00 46.00 121.0 BD006 187074.2 8435002.0 159.5 278.50 60.50 380.7 BD007 187115.4 8435202.0 170.2 272.50 61.00 381.0 BD008 187084.1 8435201.0 180.4 272.00 61.00 320.8 BD009 187052.0 8435205.0 191.4 270.00 60.50 120.0 BD010 187024.7 8435207.0 196.2 270.00 60.00 120.0 BD011 187000.2 8435206.0 197.7 274.00 59.00 120.0 BD012 187159.7 8435298.0 183.5 272.00 61.00 305.5 BD013 187132.0 8435300.0 174.8 269.00 60.50 120.0 BD014 187103.2 8435299.0 186.5 270.00 60.00 120.0 BD015 187074.4 8435298.0 194.7 274.00 61.00 119.0 BD016 187078.9 8435101.0 160.8 270.00 60.00 270.8

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 70 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BD017 187050.0 8435101.0 169.2 270.00 60.00 120.0 BD018 187017.1 8435098.0 182.7 270.00 60.00 120.0 BD019 186966.8 8435102.0 197.7 270.00 60.00 120.0 BD020 186924.9 8435097.0 191.1 269.00 60.00 120.0 BD021 187038.4 8434901.0 158.7 269.00 60.00 270.0 BD022 187008.3 8434901.0 160.4 274.00 60.00 120.0 BD023 186980.2 8434902.0 167.8 270.00 55.00 120.0 BD024 186950.5 8434904.0 181.3 273.00 54.00 120.0 BD025 186890.2 8434900.0 194.1 270.00 60.00 120.0 BD026 187106.9 8435101.0 161.9 273.00 61.00 120.0 BD027 187174.3 8435201.0 169.5 271.00 61.50 544.0 BD028 187004.4 8434803.0 165.6 270.00 45.50 140.0 BD029 186941.9 8434800.0 185.1 270.00 45.00 120.0 BD030 187050.0 8435102.0 169.3 270.00 60.00 100.0 BD031 186926.9 8435157.0 172.9 270.00 55.00 50.0 BD032 186961.0 8435159.0 188.1 270.00 55.00 69.6 BD033 186987.3 8435158.0 191.1 270.00 55.00 100.0 BD034 187016.5 8435158.0 188.1 270.00 55.00 120.0 BD035 187042.7 8435158.0 181.0 270.00 55.00 130.0 BD036 187072.7 8435158.0 175.2 270.00 55.00 153.0 BD037 187107.8 8435156.0 167.8 273.00 55.00 150.0 BD038 187136.5 8435156.0 161.7 272.00 56.50 151.0 BD039 186953.9 8435060.0 199.0 270.00 55.00 90.0 BD040 186984.3 8435049.0 191.9 270.00 55.00 110.0 BD041 187020.3 8435052.0 179.6 270.00 55.00 120.0 BD042 187047.8 8435054.0 169.3 270.00 55.00 131.0 BD043 187082.2 8435053.0 160.8 270.00 55.00 150.0 BD044 187106.6 8435053.0 156.0 268.50 55.00 150.3 BD045 187134.5 8435059.0 156.4 269.00 55.00 150.0 BD046 187166.5 8435052.0 157.7 270.00 54.50 150.0 BD047 186915.0 8434960.0 195.6 270.00 55.00 71.0 BD048 186950.6 8434959.0 189.8 274.50 55.00 110.0 BD049 186978.8 8434959.0 180.7 274.00 55.50 120.0 BD050 187006.2 8434959.0 170.6 275.00 54.50 126.0 BD051 187043.2 8434963.0 160.6 275.00 56.50 137.1 BD052 187064.5 8434960.0 157.9 269.00 55.00 139.2

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 71 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BD053 187103.3 8434960.0 153.5 272.50 56.00 141.0 BD054 186891.2 8434869.0 198.8 270.00 55.00 50.0 BD055 186921.2 8434868.0 192.7 272.00 56.50 100.0 BD056 186953.7 8434865.0 180.3 270.00 55.00 120.0 BD057 186982.2 8434865.0 172.1 269.00 55.50 139.5 BD058 187013.1 8434865.0 163.9 270.00 56.00 140.0 BD059 187041.4 8434864.0 158.2 270.00 57.00 257.6 BD060 186917.2 8434798.0 194.9 269.50 47.00 69.6 BD061 186966.6 8434801.0 176.4 270.00 45.00 110.0 BD062 187019.6 8435260.0 207.3 272.00 55.00 80.0 BD063 187041.9 8435261.0 201.6 270.00 55.00 120.0 BD064 187072.8 8435258.0 188.5 268.00 54.00 119.0 BD065 187105.6 8435256.0 174.2 270.00 55.00 130.0 BD066 187131.0 8435260.0 168.8 270.00 55.00 140.0 BD067 186975.4 8435208.0 193.1 270.00 60.00 70.0 BD068 186983.6 8435095.0 194.1 270.00 60.00 110.0 BD069 187068.5 8434902.0 155.7 272.00 61.50 130.0 BD070 186989.9 8435097.0 193.3 4.00 90.00 120.7 BD071 186992.0 8435098.0 193.1 52.00 50.00 120.0 BD072 187074.2 8435002.0 159.5 269.50 62.50 120.0 BD073 187115.4 8435202.0 170.2 270.00 60.00 120.0 BD074 186955.0 8435000.0 188.1 270.00 60.00 120.0 BD075 187019.5 8434901.0 163.2 269.00 62.00 120.0 BD076 187138.5 8435098.0 159.8 270.00 61.50 503.0 BD077 187108.5 8434903.0 152.7 272.00 61.00 467.3 BD078 187178.6 8435002.0 156.7 270.00 60.00 393.0 BD079 187158.3 8434902.0 150.6 272.00 61.00 375.4 BD080 187118.3 8435002.0 153.7 271.00 60.00 308.5 BD081 187238.3 8435002.0 152.7 270.00 60.00 449.4 BD082 187190.0 8435098.0 160.5 269.00 61.50 299.7 BD083 187234.4 8435200.0 180.8 274.00 60.00 319.6 BD084 187303.7 8435900.0 155.2 260.00 60.00 359.4 BD085 187089.9 8434701.0 153.0 267.50 62.00 400.0 BD086 187099.6 8434801.0 153.9 273.00 62.00 366.7 BD087 187169.0 8434861.0 149.5 268.00 60.50 400.0 BD088 187184.7 8435380.0 207.8 273.00 61.00 330.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 72 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BD089 187159.9 8435499.0 221.1 270.00 60.50 303.0 BD090 187182.2 8435603.0 213.6 268.00 62.00 301.0 BD091 187371.8 8436053.0 143.2 271.00 60.00 348.6 BD092 187064.9 8435001.0 161.9 269.50 62.00 61.1 BD093 187055.8 8435037.0 168.9 270.00 47.00 187.0 BD094 187040.8 8435037.0 173.7 269.00 46.00 140.0 BD095 187028.1 8435037.0 174.3 269.00 45.00 120.0 BD096 187084.1 8435136.0 168.0 269.00 51.00 194.0 BD097 187055.2 8435137.0 171.4 272.00 50.00 171.6 BD098 187026.2 8435137.0 182.5 266.00 51.00 156.5 BD099 186993.8 8435136.0 191.7 269.00 51.00 85.0 BD100 187064.9 8435002.0 161.8 273.00 61.00 300.1 BD101 187008.0 8434900.0 162.4 270.00 60.00 120.0 BD102 187043.1 8434962.0 159.6 270.00 60.00 116.8 BD103 187074.2 8435001.0 159.4 270.00 60.00 180.0 BD104 187021.6 8435051.0 176.9 270.00 60.00 81.3 BD105 187050.0 8435101.0 168.3 270.00 60.00 121.0 BD106 187016.4 8435157.0 187.5 270.00 60.00 101.3 BD107 187219.3 8435050.0 158.9 267.50 61.00 500.0 BD108 187219.5 8434846.0 148.9 267.50 60.00 500.0 BD109 187240.3 8434951.0 150.2 270.50 60.00 499.9 BD110 187120.1 8434754.0 154.4 267.50 60.00 392.5 BD111 187248.2 8435160.0 176.9 264.50 62.00 500.0 BD112 187304.7 8435300.0 172.2 267.50 55.50 478.8 BD113 187249.3 8435271.0 186.9 269.50 60.00 501.8 BD114 187225.9 8435325.0 198.6 267.00 60.00 350.1 BD115 187311.6 8435497.0 174.3 269.50 61.00 520.6 BD116 187306.1 8435402.0 159.6 270.50 60.00 501.3 BD117 187044.3 8434705.0 156.5 270.50 60.00 249.9 BD118 187044.3 8434801.0 159.2 269.50 57.00 260.2 BD119 187232.2 8434751.0 147.8 269.50 58.00 115.0 BD120 187153.0 8434812.0 150.8 269.50 59.50 113.0 BD121 187200.2 8434852.0 148.4 269.50 63.00 120.0 BD122 187008.2 8434745.0 164.9 269.50 58.00 218.8 BD123 187003.9 8434902.0 162.5 269.50 57.00 219.6 BD124 187094.5 8435045.0 159.4 269.50 57.50 314.8

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 73 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BD125 187118.6 8435151.0 164.8 269.50 57.00 296.7 BD126 187097.7 8435301.0 188.9 269.50 63.50 312.8 BD127 187134.4 8435251.0 169.5 269.50 57.00 350.5 BD128 187195.2 8435402.0 198.8 269.50 64.00 401.0 BD129 187069.9 8434751.0 154.7 270.00 57.00 278.0 BD130 187098.5 8434851.0 153.9 270.00 55.50 302.3 BD131 187120.1 8434951.0 152.5 270.00 58.00 362.0 BD132 187192.3 8435151.0 166.2 269.50 59.00 380.2 BD133 187110.7 8435252.0 172.7 270.00 58.50 271.4 BD134 187221.7 8435344.0 195.1 270.00 60.00 410.0 BD135 187118.4 8434951.0 152.6 270.00 58.00 78.0 BD136 187167.7 8435035.0 157.5 271.00 59.00 407.2 BD137 187065.5 8434652.0 151.9 270.00 58.50 300.0 BD138 187286.5 8435001.0 151.7 267.50 60.00 400.0 BD139 187369.8 8435101.0 157.8 270.00 61.30 444.0 BD140 187287.8 8435091.0 161.9 269.50 60.00 239.8 BD141 187334.4 8435154.0 163.2 270.00 60.00 333.0 BD142 187321.6 8435200.0 159.4 270.00 60.00 270.0 BD143 187361.8 8435303.0 159.6 270.00 59.00 248.8 BD144 187332.0 8435300.0 166.3 270.00 60.00 309.8 BD145 187381.8 8435404.0 151.7 270.00 61.00 269.3 BD146 187377.1 8435609.0 152.4 270.00 60.00 180.0 BD147 187376.6 8435702.0 159.5 270.00 60.00 227.8 BD148 186999.2 8434642.0 163.0 272.50 61.00 206.8 BD149 186983.5 8434601.0 162.9 270.00 60.00 198.4 BD150 186984.2 8434502.0 153.9 269.50 60.00 129.0 BD151 186998.8 8434553.0 155.2 269.50 61.00 170.0 BD152 187296.0 8435049.0 153.5 280.00 59.00 300.0 BD153 187371.1 8435204.0 150.0 268.50 60.00 219.5 BD154 187320.2 8435355.0 158.8 273.00 59.00 255.6 BD155 187015.4 8434500.0 150.7 274.50 60.00 159.5 BD156 187039.5 8435352.0 183.3 272.50 61.00 138.5 BD157 187088.4 8435351.0 178.8 277.50 60.00 206.0 BD158 187139.1 8435351.0 178.8 272.50 60.00 280.2 BD159 187089.8 8435456.0 187.1 268.50 61.00 195.5 BD160 187139.3 8435452.0 187.2 270.00 60.00 171.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 74 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BD161 187189.5 8435451.0 187.0 269.50 61.00 193.8 BD162 187119.1 8435552.0 186.6 270.00 60.00 147.4 BD163 187167.2 8435553.0 186.7 272.50 61.00 219.0 BD164 187203.7 8435551.0 186.7 272.50 60.00 150.3 BD165 187253.4 8435552.0 183.5 268.50 60.00 303.0 BD166 187168.2 8435651.0 187.0 272.50 60.00 144.4 BD167 187218.4 8435652.0 186.9 269.50 60.00 169.4 BD168 186909.1 8435405.0 177.4 82.00 50.00 340.0 BD169 187018.0 8435114.0 155.0 266.50 50.50 145.0 BD170 186719.3 8434799.0 182.9 84.50 48.00 450.0 BD171 187039.8 8434951.0 151.5 270.00 60.00 21.9 BD172 187040.7 8434951.0 151.5 270.00 60.00 168.2 BD173 187259.3 8435202.0 171.6 270.00 60.50 370.0 BD174 187169.4 8435251.0 167.2 275.00 61.00 190.0 BD175 187094.0 8435202.0 163.0 265.50 61.50 182.0 BD176 187061.5 8434902.0 154.8 270.50 60.00 171.5 BD177 187174.6 8435351.0 167.3 269.00 60.00 188.0 BD178 187180.1 8434951.0 152.1 277.00 60.00 212.0 BD179 187249.0 8435052.0 158.0 273.50 59.00 208.0 BD180 186974.1 8435002.0 130.7 272.00 58.00 151.0 BD181 187109.2 8435102.0 159.7 270.00 60.00 181.0 BD182 187242.2 8435502.0 178.9 270.00 60.00 405.0 BD183 187291.4 8435601.0 179.2 270.00 60.00 493.3 BD184 187197.1 8435713.0 186.8 278.50 61.00 263.8 BD185 187298.8 8435702.0 178.8 267.50 60.50 398.8 BD186 187326.8 8435800.0 167.8 283.50 58.00 401.6 BD187 187423.2 8435805.0 149.8 269.50 61.00 497.9 BD188 187242.5 8435900.0 151.5 269.50 61.00 353.9 BD189 187364.1 8435903.0 159.0 270.00 45.00 549.7 BD190 187207.3 8435502.0 175.2 270.00 60.00 212.7 BD191 187258.0 8435502.0 175.1 270.00 60.00 206.5 BD192 187080.3 8435508.0 163.3 270.00 60.00 100.0 BD193 187103.9 8435506.0 162.9 270.00 60.00 150.1 BD194 187149.4 8435502.0 162.6 270.00 65.00 209.9 BD195 187289.5 8435507.0 179.2 270.00 60.00 199.9 BD196 187333.1 8435501.0 167.8 270.00 60.00 199.9

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 75 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BD197 187364.5 8435500.0 156.0 270.00 60.00 201.6 BD198 187229.1 8435402.0 175.3 270.00 60.00 302.8 BD199 187205.8 8435452.0 175.6 270.00 60.00 251.7 BD200 187094.1 8435451.0 147.2 270.00 60.00 150.5 BD201 187128.3 8435451.0 147.6 270.00 65.00 200.0 BD202 187407.6 8435462.0 167.2 270.00 60.00 200.0 BD203 187254.5 8435452.0 175.6 270.00 60.00 205.9 BD204 187244.2 8435602.0 175.0 270.00 65.00 214.8 BD205 187219.0 8435602.0 174.8 270.00 65.00 199.6 BD206 187116.5 8435610.0 178.7 270.00 60.00 148.0 BD207 187217.3 8435546.0 170.7 270.00 60.00 212.9 BD208 187188.5 8435602.0 175.1 267.50 60.00 204.5 BD209 187243.3 8434899.0 147.0 269.00 58.00 148.0 BD210 187194.1 8435002.0 140.5 266.00 64.00 1.0 BD211 187209.1 8435002.0 140.8 257.00 63.00 0.0 BD212 187200.3 8435001.0 140.6 258.00 65.00 465.7 BD213 187248.0 8434901.0 146.8 259.50 58.00 360.7 BD214 187331.3 8435266.0 162.8 265.50 64.00 300.5 BD215 187240.5 8435350.0 162.9 270.50 69.00 261.2 BD216 187039.2 8435251.0 123.3 269.50 57.00 131.0 BD217 187208.8 8435065.0 140.8 279.50 67.00 326.8 BD218 187133.6 8434801.0 135.4 263.50 68.00 239.4 BD219 186994.0 8434950.0 123.2 261.50 70.00 210.5 BD220 187166.0 8435259.0 122.6 270.50 66.00 299.7 BD221 187109.8 8434852.0 134.8 259.50 69.00 260.6 BD222 187264.7 8434851.0 146.4 267.50 70.00 120.0 BD223 187364.7 8435065.0 145.8 256.50 60.00 148.0 BD224 187131.7 8434952.0 134.7 261.50 69.00 334.7 BD225 187295.5 8435452.0 161.9 267.50 63.00 140.0 BD226 187389.0 8435356.0 149.4 263.50 61.00 200.0 BP001 187074.4 8435004.0 159.4 270.00 62.00 78.0 BP002 187040.2 8435004.0 167.9 270.00 60.00 81.0 BP003 187011.1 8435007.0 176.8 270.00 60.00 126.0 BP004 186986.2 8435007.0 184.5 270.00 60.00 76.0 BP005 186949.9 8435011.0 194.0 269.50 63.00 81.0 BP006 187114.8 8435203.0 170.2 270.00 60.00 81.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 76 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BP007 187082.4 8435202.0 180.4 269.00 60.00 81.0 BP008 187052.5 8435206.0 191.4 268.00 62.00 82.0 BP009 187023.9 8435208.0 196.2 270.50 61.50 81.0 BP010 186999.3 8435206.0 197.6 270.00 60.00 81.0 BP011 186956.7 8435097.0 199.4 270.00 60.00 81.0 BP012 187211.5 8435604.0 210.0 269.50 60.50 81.0 BP013 187182.2 8435603.0 213.6 268.00 62.00 81.0 BP014 187161.6 8435605.0 215.6 269.50 63.50 141.0 BP015 186984.4 8435097.0 193.5 270.00 60.00 81.0 BP016 186922.9 8434906.0 191.5 294.00 61.50 81.0 BP017 187044.1 8435296.0 204.8 271.00 60.00 81.0 BP018 187000.3 8434801.0 166.1 269.00 61.50 124.0 BP019 186939.0 8434800.0 185.6 270.00 60.00 120.0 BP020 186879.2 8434799.0 202.7 272.00 62.00 120.0 BP021 186899.6 8434699.0 189.5 270.00 60.00 120.0 BP022 186955.0 8434699.0 188.1 273.00 61.50 120.0 BP023 187019.5 8434700.0 163.2 272.50 61.50 120.0 BP024 186872.0 8434601.0 169.0 271.00 60.00 120.0 BP025 186935.3 8434602.0 170.7 275.00 61.50 120.0 BP026 186993.7 8434601.0 163.9 278.00 61.50 120.0 BP027 187174.3 8435201.0 169.5 271.00 61.50 120.0 BP028 187234.4 8435200.0 180.8 274.00 60.00 120.0 BP029 187290.9 8435199.0 171.7 274.00 61.00 120.0 BP030 187354.1 8435199.0 151.3 270.00 60.00 120.0 BP031 187415.8 8435201.0 147.5 270.00 60.00 120.0 BP032 187368.9 8435404.0 153.9 268.00 61.50 120.0 BP033 187311.0 8435400.0 158.7 270.00 60.00 120.0 BP034 187417.9 8435002.0 147.1 270.00 60.00 100.0 BP035 187479.2 8435004.0 144.2 270.00 60.00 120.0 BP036 187253.7 8435398.0 170.5 270.00 60.00 120.0 BP038 187129.4 8435397.0 213.7 274.00 61.00 120.0 BP039 187118.3 8435002.0 153.7 271.00 60.00 120.0 BP040 187068.8 8435396.0 207.7 268.00 59.00 120.0 BP041 187178.6 8435002.0 156.7 270.00 60.00 120.0 BP042 187184.7 8435380.0 207.8 273.00 61.00 120.0 BP043 187238.3 8435002.0 152.7 270.00 60.00 120.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 77 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BP044 187372.4 8435600.0 153.9 271.50 63.50 120.0 BP045 187298.1 8435002.0 150.0 270.00 60.00 120.0 BP046 187311.5 8435603.0 174.2 270.00 60.00 120.0 BP047 187357.6 8435002.0 149.5 270.00 60.00 105.0 BP048 187322.7 8435802.0 167.8 269.00 61.50 120.0 BP049 187434.6 8435400.0 145.7 269.00 60.00 120.0 BP050 187257.9 8435799.0 150.6 270.00 60.00 120.0 BP051 187387.4 8435802.0 155.1 270.00 60.00 120.0 BP052 187203.0 8435801.0 175.7 271.00 62.00 120.0 BP053 187379.2 8436001.0 136.7 266.00 58.50 120.0 BP054 187151.1 8435799.0 176.4 270.00 60.00 120.0 BP055 187320.1 8435999.0 136.8 271.50 59.00 120.0 BP056 187335.3 8435700.0 169.8 270.00 60.00 120.0 BP057 187257.1 8435994.0 137.0 270.00 60.00 120.0 BP058 187283.2 8435701.0 185.1 270.00 60.00 120.0 BP059 187194.3 8435999.0 144.1 272.00 60.00 120.0 BP060 187222.0 8435696.0 188.0 269.00 60.00 120.0 BP061 187364.1 8435903.0 159.0 270.00 60.00 120.0 BP062 187159.5 8435693.0 208.7 268.00 60.00 120.0 BP063 187303.7 8435900.0 155.2 260.00 60.00 117.0 BP064 187258.3 8435501.0 183.6 270.00 60.00 120.0 BP065 187184.3 8435896.0 154.5 266.50 60.50 120.0 BP066 187195.6 8435507.0 210.0 274.00 62.00 120.0 BP067 187240.8 8435807.0 159.6 269.50 61.00 120.0 BP068 187130.3 8435500.0 223.5 278.50 61.00 118.0 BP069 187215.9 8435603.0 209.3 270.00 65.50 120.0 BP070 187308.1 8435001.0 149.6 4.00 90.00 60.0 BP071 187258.5 8435301.0 186.3 275.00 60.00 120.0 BP072 187307.0 8435300.0 171.8 271.00 51.50 120.0 BP073 187365.0 8435302.0 159.3 274.50 53.00 120.0 BP074 187414.5 8435301.0 151.9 270.00 60.00 120.0 BP075 187340.0 8435400.0 152.7 270.00 60.00 100.0 BP076 187407.4 8435398.0 146.7 271.50 61.00 130.0 BP077 187312.8 8435500.0 174.2 269.50 61.50 120.0 BP078 187363.2 8435507.0 156.7 275.00 61.00 120.0 BP079 187409.2 8435503.0 150.2 272.00 61.00 120.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 78 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BP080 187461.4 8435501.0 148.2 271.00 60.00 120.0 BP081 187189.8 8435695.0 199.4 269.50 59.00 100.0 BP082 187169.5 8435746.0 195.8 248.00 60.00 60.0 BP083 186925.7 8434999.0 196.5 272.50 59.00 75.0 BP084 186922.7 8434698.0 192.0 270.00 60.50 90.0 BP085 187178.2 8435801.0 179.8 270.00 60.00 60.0 BP086 187228.3 8435801.0 164.0 265.00 61.00 120.0 BP087 187286.5 8435799.0 160.4 270.00 60.00 140.0 BP088 187199.2 8435844.0 171.9 270.00 60.00 70.0 BP089 187230.9 8435847.0 160.7 268.00 61.50 110.0 BP090 187263.4 8435848.0 149.2 270.00 62.00 120.0 BP091 187169.2 8435156.0 163.3 253.00 61.00 120.0 BP092 187197.8 8435054.0 159.9 269.00 61.00 120.0 BP093 187134.5 8434960.0 152.4 275.00 61.00 120.0 BP094 187074.3 8434864.0 155.1 270.00 60.00 120.0 BP095 186988.9 8434699.0 171.6 269.50 60.00 120.0 BP096 187169.5 8435256.0 178.7 273.00 61.00 120.0 BP097 186948.8 8435208.0 185.7 271.50 63.00 50.0 BP098 187138.5 8435098.0 159.8 270.00 61.50 130.0 BP099 186989.9 8435262.0 202.3 273.00 65.50 100.0 BP100 187108.5 8434903.0 152.7 272.00 61.00 120.0 BP101 187026.9 8434403.0 146.7 269.00 61.50 50.0 BP102 187001.5 8434403.0 147.7 270.00 60.50 50.0 BP103 186982.6 8434404.0 147.9 274.00 60.00 50.0 BP104 186926.0 8434403.0 151.7 271.50 60.50 50.0 BP105 187335.1 8435399.0 153.0 94.00 60.00 50.0 BP111 186989.6 8435096.0 193.6 4.00 90.00 103.0 BP112 186986.4 8435081.0 193.2 4.00 90.00 101.0 BP113 186985.3 8435066.0 193.0 4.00 90.00 103.0 BP114 186978.8 8435036.0 192.5 4.00 90.00 102.0 BP115 186959.2 8434997.0 191.7 4.00 90.00 94.0 BP116 186946.0 8435001.0 194.6 4.00 90.00 83.0 BP117 186961.2 8435038.0 196.2 4.00 90.00 100.0 BP118 186968.8 8435052.0 196.9 4.00 90.00 104.0 BP119 186974.9 8435067.0 197.0 4.00 90.00 103.0 BP120 186978.2 8435100.0 195.6 4.00 90.00 87.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 79 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BP121 186947.0 8435069.0 198.1 4.00 90.00 112.0 BP122 186945.3 8435054.0 196.8 94.00 90.00 111.0 BP123 186944.0 8435039.0 195.6 94.00 90.00 110.0 BP124 186906.3 8435002.0 191.0 4.00 90.00 100.0 BP125 186923.8 8435040.0 190.8 4.00 90.00 102.0 BP126 186927.9 8435054.0 191.2 55.00 89.00 106.0 BP127 186929.4 8435069.0 191.8 55.00 89.50 104.0 BP128 186936.9 8435102.0 194.0 4.00 90.00 85.0 BP129 186915.8 8435070.0 186.2 4.00 90.00 85.0 BP130 186916.1 8435055.0 185.4 4.00 90.00 50.0 BP131 186909.9 8435041.0 186.0 4.00 90.00 79.0 BP132 186892.7 8435004.0 186.8 4.00 90.00 80.0 BP133 186940.0 8435172.0 176.0 4.00 90.00 75.0 BP134 186998.9 8435067.0 187.9 4.00 90.00 102.0 BP135 186997.3 8435047.0 187.8 4.00 90.00 102.0 BP136 186994.2 8435037.0 188.0 4.00 90.00 102.0 BP137 187007.7 8435038.0 182.5 4.00 90.00 96.0 BP138 187014.0 8435066.0 182.1 4.00 90.00 96.0 BP139 187022.2 8435101.0 182.4 4.00 90.00 96.0 BP140 187034.5 8435101.0 177.1 4.00 90.00 89.0 BP141 187026.7 8435064.0 178.3 4.00 90.00 92.0 BP142 187019.5 8435039.0 178.6 4.00 90.00 93.0 BP143 187022.6 8435011.0 174.3 4.00 90.00 88.0 BP144 187031.3 8435038.0 175.1 4.00 90.00 89.0 BP145 187033.5 8435049.0 175.2 4.00 90.00 89.0 BP146 187046.6 8435064.0 170.3 4.00 90.00 84.0 BP147 187053.3 8435102.0 169.3 4.00 90.00 83.0 BP148 187053.1 8435082.0 168.0 4.00 90.00 82.0 BP149 187054.1 8435069.0 168.8 4.00 90.00 83.0 BP150 187044.2 8435048.0 170.9 4.00 90.00 85.0 BP151 187043.7 8435038.0 170.2 4.00 90.00 84.0 BP152 187040.9 8435024.0 170.2 4.00 90.00 84.0 BP153 187079.5 8435083.0 161.0 4.00 90.00 76.0 BP154 187075.7 8435102.0 161.6 4.00 90.00 76.0 BP155 187071.1 8435137.0 165.3 4.00 90.00 79.0 BP156 187057.8 8435137.0 171.4 4.00 90.00 84.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 80 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BP157 187038.7 8435136.0 178.1 4.00 90.00 92.0 BP158 187026.1 8435135.0 182.5 4.00 90.00 94.0 BP159 187010.2 8435134.0 186.8 4.00 90.00 101.0 BP160 186994.5 8435134.0 191.7 4.00 90.00 106.0 BP161 186979.2 8435134.0 193.3 4.00 90.00 70.0 BP162 186965.0 8435135.0 189.0 4.00 90.00 103.0 BP163 186949.1 8435133.0 185.9 4.00 90.00 100.0 BP164 186931.1 8435133.0 182.2 4.00 90.00 96.0 BP165 186914.9 8435133.0 179.1 4.00 90.00 93.0 BP166 187045.5 8435173.0 185.3 4.00 90.00 84.0 BP167 187029.7 8435173.0 185.9 4.00 90.00 91.0 BP168 187018.1 8435173.0 186.8 4.00 90.00 95.0 BP169 187000.5 8435174.0 192.8 4.00 90.00 97.0 BP170 186986.0 8435173.0 193.5 4.00 90.00 93.0 BP171 186970.0 8435175.0 190.0 4.00 90.00 85.0 BP172 186956.4 8435174.0 186.2 4.00 90.00 83.0 BP175 187158.3 8434902.0 150.6 272.00 61.00 120.0 BP176 187190.0 8435098.0 160.5 269.00 61.50 91.0 BP177 187161.0 8435397.0 216.0 268.00 60.00 60.0 BP178 187098.8 8435396.0 213.4 268.00 60.00 60.0 BP179 187038.4 8435396.0 201.7 269.00 59.50 60.0 BP180 187287.0 8435501.0 180.0 270.00 60.50 60.0 BP181 187225.9 8435507.0 194.9 271.00 60.00 60.0 BP182 187159.9 8435499.0 221.1 270.00 60.50 60.0 BP183 187101.1 8435499.0 222.4 269.50 59.50 60.0 BP184 187276.3 8435603.0 191.0 271.00 60.00 60.0 BP185 187244.2 8435602.0 202.8 270.00 60.00 60.0 BP186 187132.5 8435605.0 213.1 269.00 60.00 60.0 BP187 187101.1 8435606.0 200.6 275.00 60.00 60.0 BP188 186964.0 8435022.0 193.8 290.50 49.50 30.0 BP189 186961.4 8435023.0 194.0 290.00 50.00 30.0 BP190 186958.6 8435024.0 194.2 290.00 50.00 30.0 BP191 186955.7 8435024.0 194.3 290.00 50.00 30.0 BP192 186952.6 8435025.0 194.5 290.50 50.00 30.0 BP193 186969.2 8435035.0 194.6 291.00 50.00 30.0 BP194 186966.7 8435035.0 194.8 290.00 50.00 30.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 81 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BP195 186963.9 8435037.0 194.9 289.50 50.00 30.0 BP196 186960.4 8435038.0 195.1 290.00 50.00 30.0 BP197 186957.6 8435039.0 195.3 291.00 49.00 30.0 BP198 186974.6 8435050.0 195.8 286.00 49.00 30.0 BP199 186972.0 8435050.0 196.1 287.00 50.00 30.0 BP200 186969.3 8435051.0 196.4 290.00 50.00 30.0 BP201 186966.2 8435052.0 196.6 290.00 50.00 30.0 BP202 186963.3 8435053.0 196.6 290.00 50.00 30.0 BP203 186979.8 8435064.0 195.8 290.00 50.00 30.0 BP204 186977.1 8435065.0 196.1 290.00 50.00 30.0 BP205 186974.1 8435066.0 196.5 290.00 50.00 30.0 BP206 186971.3 8435067.0 196.9 290.00 50.00 30.0 BP207 186968.7 8435068.0 197.1 291.50 51.00 30.0 BP208 187089.9 8434701.0 153.0 267.50 62.00 90.0 BP209 187110.1 8434862.0 153.2 276.50 60.50 150.0 BP210 187169.0 8434861.0 149.5 268.00 60.50 150.0 BP211 187049.1 8434801.0 158.4 269.50 62.00 100.0 BP212 187099.6 8434801.0 153.9 273.00 62.00 100.0 BP213 187148.9 8434801.0 150.2 271.00 61.00 100.0 BP214 187198.1 8434801.0 147.7 271.00 60.00 100.0 BP215 187249.0 8434801.0 146.3 271.00 61.00 100.0 BP216 187299.5 8434801.0 145.0 275.00 61.50 100.0 BP217 187348.1 8434801.0 144.0 270.00 60.50 100.0 BP218 187398.9 8434801.0 141.6 270.00 61.50 100.0 BP219 187449.8 8434801.0 140.3 271.00 59.50 100.0 BP220 187498.5 8434801.0 140.3 271.00 60.50 100.0 BP221 187118.5 8434861.0 152.4 288.50 50.00 20.0 BP222 187075.2 8435002.0 159.3 267.50 61.00 90.0 BP223 187041.1 8435004.0 167.8 271.00 60.00 100.0 BP224 187022.4 8435011.0 174.4 268.00 60.00 110.0 BP225 187011.0 8435006.0 176.7 269.00 61.00 110.0 BP226 186986.7 8435007.0 182.9 263.50 60.50 120.0 BP227 186959.6 8434996.0 191.1 266.00 61.00 120.0 BP228 186951.6 8435009.0 193.7 266.00 60.00 120.0 BP229 187081.2 8435054.0 160.8 269.00 56.00 110.0 BP230 187048.6 8435053.0 169.8 265.00 56.00 110.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 82 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BP231 187032.2 8435049.0 175.2 264.50 61.50 110.0 BP232 187018.7 8435051.0 178.7 269.50 55.50 120.0 BP233 186975.2 8435050.0 195.8 266.50 59.00 120.0 BP234 186951.6 8435061.0 197.1 267.50 54.50 90.0 BP235 186945.1 8435055.0 196.9 264.00 60.00 80.0 BP236 186926.6 8435054.0 191.3 262.00 60.50 50.0 BP237 187052.9 8435068.0 168.4 266.00 61.50 100.0 BP238 187046.6 8435064.0 169.3 262.00 60.50 105.0 BP239 187025.8 8435063.0 177.8 270.00 61.50 115.0 BP240 187012.7 8435067.0 182.1 268.00 61.00 120.0 BP241 186973.9 8435067.0 196.4 268.00 60.50 120.0 BP242 186959.4 8435067.0 197.2 268.00 60.50 120.0 BP243 186946.5 8435068.0 197.6 267.00 59.50 80.0 BP244 186928.4 8435070.0 192.4 262.00 60.00 50.0 BP245 187371.8 8436053.0 143.2 271.00 60.00 104.8 BP248 187519.6 8435601.0 141.8 268.00 60.00 50.0 BP249 187469.6 8435602.0 142.3 270.00 60.00 60.0 BP250 187420.2 8435611.0 145.5 271.00 60.00 54.0 BP254 187519.1 8435802.0 141.7 270.00 59.00 50.0 BP255 187473.0 8435801.0 144.7 266.00 60.00 45.0 BP256 187445.1 8435802.0 147.0 270.00 60.00 24.0 BP257 187500.1 8435801.0 141.9 270.00 61.00 50.0 BP261 187393.0 8435602.0 149.4 267.00 61.00 50.0 BP262 187444.4 8435602.0 144.3 273.00 61.00 50.0 BP263 187493.9 8435602.0 141.6 268.00 61.00 50.0 BP266 187445.7 8435801.0 146.6 273.00 60.00 50.0 BP267 187008.0 8434900.0 162.4 270.00 60.00 61.8 BP268 187043.1 8434962.0 159.6 270.00 60.00 85.0 BP269 187074.2 8435001.0 159.4 270.00 60.00 58.0 BP270 187021.6 8435051.0 176.9 270.00 60.00 70.3 BP271 187050.0 8435101.0 168.3 270.00 60.00 70.0 BP272 187016.4 8435157.0 187.5 270.00 60.00 50.0 BP273 186919.1 8435135.0 180.1 268.00 50.00 45.0 BP274 186942.7 8435136.0 185.1 265.00 52.00 45.0 BP275 186975.1 8435135.0 192.7 269.00 49.00 45.0 BP276 187108.1 8435136.0 167.0 268.00 51.00 40.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 83 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BP277 187133.0 8435137.0 162.0 268.00 52.00 36.0 BP278 186873.1 8434751.0 203.0 266.00 49.00 50.0 BP279 186892.8 8434751.0 201.3 268.00 51.00 50.0 BP280 186920.8 8434750.0 192.6 267.00 51.00 50.0 BP281 186944.5 8434752.0 183.2 267.00 50.00 50.0 BP282 186971.0 8434752.0 174.6 270.00 49.00 45.0 BP283 186994.3 8434751.0 168.7 263.00 50.00 45.0 BP284 187018.0 8434751.0 161.8 269.00 50.00 45.0 BP285 187040.0 8434751.0 157.3 269.00 50.00 45.0 BP286 186895.2 8434832.0 201.8 266.00 51.00 65.0 BP287 186921.2 8434830.0 195.9 268.00 50.00 65.0 BP288 186944.3 8434832.0 187.8 269.00 50.00 55.0 BP289 186967.9 8434831.0 180.7 268.00 49.00 45.0 BP290 186993.0 8434831.0 171.9 268.00 49.00 45.0 BP291 187018.8 8434831.0 166.1 266.00 51.00 45.0 BP292 187044.3 8434831.0 160.1 268.00 52.00 35.0 BP293 187068.0 8434831.0 157.4 268.00 52.00 25.0 BP294 186892.4 8434884.0 196.8 270.00 50.00 65.0 BP295 186916.7 8434881.0 192.6 269.00 51.00 60.0 BP296 186944.6 8434882.0 181.1 267.00 49.00 55.0 BP297 186970.1 8434880.0 170.4 265.00 43.00 50.0 BP298 186994.5 8434882.0 162.5 268.00 51.00 40.0 BP299 187018.2 8434881.0 159.0 268.00 50.00 40.0 BP300 187043.3 8434881.0 156.8 272.00 51.00 35.0 BP301 187068.1 8434881.0 155.8 273.00 50.00 30.0 BP302 187093.4 8434882.0 153.7 270.00 51.00 25.0 BP303 186900.6 8434931.0 195.0 269.00 51.00 60.0 BP304 186917.7 8434931.0 193.6 268.00 51.00 60.0 BP305 186946.0 8434931.0 186.7 271.00 48.00 60.0 BP306 186969.2 8434931.0 180.0 265.00 50.00 50.0 BP307 186994.8 8434934.0 172.4 271.00 51.00 45.0 BP308 187020.5 8434931.0 166.1 271.00 51.00 35.0 BP309 187045.8 8434933.0 160.4 269.00 51.00 35.0 BP310 187067.6 8434931.0 156.4 270.00 51.00 35.0 BP311 187094.1 8434931.0 154.2 270.00 51.00 25.0 BP312 186917.8 8435032.0 190.6 269.00 50.00 60.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 84 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BP313 186943.6 8435036.0 195.4 269.00 50.00 65.0 BP314 186968.1 8435036.0 194.6 272.00 50.00 65.0 BP315 186992.8 8435035.0 188.1 271.00 50.00 65.0 BP316 187019.4 8435036.0 176.5 266.00 51.00 60.0 BP317 187072.3 8435036.0 162.6 270.00 51.00 35.0 BP318 187103.4 8435036.0 156.1 272.00 51.00 25.0 BP319 186953.2 8435181.0 185.9 268.00 55.00 40.0 BP320 186968.5 8435182.0 189.8 276.00 55.00 45.0 BP321 186992.8 8435182.0 193.9 265.00 53.00 45.0 BP322 187024.9 8435174.0 186.1 271.00 49.00 40.0 BP323 187042.8 8435179.0 185.4 270.00 50.00 40.0 BP324 187067.2 8435182.0 181.2 271.00 49.00 35.0 BP325 187091.6 8435182.0 175.4 271.00 50.00 35.0 BP326 187114.9 8435184.0 168.8 271.00 50.00 25.0 BP327 187139.2 8435184.0 163.1 272.00 51.00 25.0 BP328 187169.9 8435186.0 167.7 275.00 51.00 30.0 BP329 186970.9 8435212.0 194.5 267.00 53.00 50.0 BP330 186994.7 8435228.0 199.9 267.00 51.00 60.0 BP331 187021.0 8435232.0 202.6 268.00 52.00 60.0 BP332 187043.0 8435233.0 198.8 279.00 51.00 60.0 BP333 187070.2 8435232.0 188.3 271.00 50.00 45.0 BP334 187096.2 8435232.0 178.5 269.00 50.00 35.0 BP335 187118.9 8435232.0 170.9 272.00 52.00 25.0 BP336 187137.0 8435233.0 166.2 270.00 52.00 25.0 BP337 187170.3 8435232.0 174.5 273.00 51.00 30.0 BP338 186990.6 8435271.0 202.5 273.00 58.00 60.0 BP339 187015.1 8435280.0 209.6 270.00 50.00 60.0 BP340 187040.7 8435291.0 205.4 274.00 48.00 60.0 BP341 187074.0 8435281.0 190.0 271.00 50.00 50.0 BP342 187119.1 8435281.0 173.6 292.00 51.00 30.0 BP343 187140.5 8435282.0 178.9 266.00 50.00 25.0 BP344 187168.0 8435282.0 183.3 267.00 51.00 35.0 BP345 186889.0 8435004.0 186.0 265.00 50.00 70.0 BP346 186850.0 8435001.0 175.6 268.00 51.00 70.0 BP347 186804.2 8435001.0 167.8 267.00 49.00 70.0 BP348 186856.7 8435118.0 168.2 248.00 57.00 68.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 85 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BP349 186917.0 8434552.0 163.5 270.50 60.50 60.0 BP350 186898.7 8434553.0 163.8 268.50 60.00 84.0 BP351 186904.6 8434602.0 165.2 270.50 62.00 86.0 BP352 186864.6 8434648.0 177.1 265.50 61.00 60.0 BP353 186870.8 8434555.0 165.1 268.50 60.00 50.0 BP354 186873.8 8434504.0 161.2 269.50 61.00 56.0 BP355 186906.4 8434500.0 154.9 269.50 60.00 84.0 BP356 186954.2 8434500.0 157.9 267.50 60.00 66.0 BP357 186966.3 8434453.0 153.3 266.50 60.00 72.0 BP358 186886.5 8434447.0 158.8 269.50 61.00 58.0 BP359 186896.4 8434399.0 154.8 264.50 60.00 60.0 BP360 186950.9 8434399.0 148.2 268.50 60.00 78.0 BP361 186930.2 8434501.0 157.9 268.50 60.00 50.0 BP362 186949.8 8434654.0 181.5 269.50 60.00 90.0 BP363 186927.9 8434651.0 182.2 266.50 60.00 54.0 BP364 186974.1 8434653.0 175.0 267.50 60.00 50.0 BP365 186968.3 8434603.0 167.5 266.50 60.00 84.0 BP366 186950.8 8434553.0 155.9 268.50 60.00 60.0 BP367 186943.8 8434450.0 152.3 264.50 60.00 54.0 BP368 186911.0 8434454.0 152.9 268.50 61.00 84.0 BP369 186972.1 8434551.0 155.3 266.00 60.00 42.0 BP370 186968.0 8434551.0 155.4 269.50 61.00 90.0 BP371 187238.6 8434750.0 147.6 269.50 63.00 58.0 BP372 187259.1 8435051.0 156.6 269.50 60.00 100.0 BP373 187239.2 8435101.0 165.4 269.50 59.50 100.0 BP374 187287.8 8435091.0 161.9 269.50 60.00 102.0 BP375 187208.2 8435151.0 168.1 269.50 60.00 101.0 BP376 187291.6 8435152.0 175.9 269.50 59.00 114.0 BP377 187261.0 8435201.0 182.8 269.50 59.00 100.0 BP378 187319.6 8435202.0 159.4 269.50 60.00 100.0 BP379 187220.6 8435252.0 191.5 269.50 60.00 102.0 BP380 187293.6 8435256.0 169.8 269.50 60.00 113.0 BP381 187218.0 8435302.0 197.3 269.50 59.50 100.0 BP382 187283.2 8435301.0 177.7 269.50 60.00 100.0 BP383 187211.0 8435352.0 198.8 269.50 59.00 100.0 BP384 187269.1 8435352.0 177.1 269.50 59.00 100.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 86 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BP385 187320.2 8435355.0 158.8 269.50 61.00 100.0 BP386 187280.7 8435402.0 162.2 269.50 59.00 100.0 BP387 187381.8 8435404.0 151.7 269.50 61.00 102.0 BP388 187247.2 8435451.0 182.6 269.50 60.00 100.0 BP389 187283.3 8435444.0 170.5 269.50 61.00 100.0 BP390 187345.3 8435456.0 162.9 269.50 59.00 100.0 BP391 187242.4 8435552.0 198.5 269.50 59.00 100.0 BP392 187283.5 8435554.0 190.8 269.50 58.50 100.0 BP393 187333.5 8435552.0 167.9 269.50 61.00 100.0 BP394 187345.6 8435600.0 163.9 269.50 59.00 100.0 BP395 187266.4 8435660.0 184.8 269.50 59.00 100.0 BP396 187316.6 8435655.0 165.0 269.50 60.00 100.0 BP397 187368.9 8435649.0 153.8 269.50 60.00 101.0 BP398 187376.6 8435702.0 159.5 269.50 60.00 100.0 BP399 187255.5 8435701.0 185.8 269.50 60.00 100.0 BP400 187305.8 8435704.0 180.5 269.50 60.50 101.0 BP401 187170.5 8435751.0 195.1 269.50 60.00 83.0 BP402 187231.7 8435755.0 165.7 269.50 53.00 130.0 BP403 187270.1 8435747.0 169.8 269.50 61.00 100.0 BP404 187190.5 8435805.0 178.7 269.50 60.00 100.0 BP405 187216.3 8435903.0 154.7 269.50 60.00 113.0 BP406 187242.5 8435900.0 151.5 269.50 61.00 100.0 BP407 187296.0 8435049.0 153.5 269.50 60.00 100.0 BP408 187169.6 8435104.0 158.6 269.50 60.00 97.0 BP409 187211.5 8435108.0 163.7 269.50 59.00 108.0 BP410 187265.9 8435101.0 164.6 269.50 60.00 102.0 BP411 187323.5 8435103.0 168.9 269.50 60.00 64.0 BP412 187328.2 8435152.0 165.4 269.50 59.20 120.0 BP413 187142.8 8435202.0 164.5 269.50 60.00 102.0 BP414 187203.3 8435206.0 175.4 269.50 60.00 108.0 BP415 187265.8 8435255.0 180.3 269.50 60.00 117.0 BP416 187204.3 8435303.0 198.5 269.50 59.00 100.0 BP417 187332.8 8435302.0 165.9 269.50 59.00 100.0 BP418 187391.9 8435302.0 156.4 269.50 60.00 102.0 BP419 187318.7 8435258.0 164.8 269.50 61.00 130.0 BP420 187195.2 8435352.0 198.8 269.50 59.00 100.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 87 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BP421 187291.8 8435352.0 166.9 269.50 60.00 100.0 BP422 187350.6 8435352.0 156.8 269.50 60.00 78.0 BP423 187253.3 8435404.0 170.2 269.50 60.00 100.0 BP424 187318.2 8435449.0 156.8 269.50 60.50 100.0 BP425 187366.3 8435451.0 160.4 269.50 60.00 100.0 BP426 187334.9 8435505.0 166.6 269.50 60.00 100.0 BP427 187308.9 8435550.0 180.9 269.50 60.50 100.0 BP428 187397.1 8435554.0 156.1 269.50 59.00 100.0 BP429 187361.8 8435303.0 159.5 270.00 59.00 120.0 BP430 187388.6 8435511.0 153.0 269.50 60.50 100.0 BP431 187372.8 8435607.0 153.8 269.50 60.00 106.0 BP432 186976.2 8435602.0 189.5 269.50 60.50 100.0 BP433 187005.1 8435602.0 186.1 269.50 60.00 101.0 BP434 187069.6 8434652.0 151.7 270.00 60.00 99.0 BP435 187016.8 8435550.0 193.6 269.50 61.00 100.0 BP443 187069.3 8435552.0 186.6 269.50 60.00 80.0 BP445 187118.8 8435651.0 186.9 270.50 60.00 80.0 BP446 187133.8 8435702.0 186.7 269.50 61.00 70.0 BP447 187144.5 8435752.0 186.6 267.50 60.50 82.0 BP448 187186.0 8435751.0 186.6 263.50 60.00 130.0 BP454 187071.2 8436002.0 172.9 272.50 60.00 80.0 BP455 187118.0 8436002.0 160.3 267.50 60.00 80.0 BP456 187171.9 8436003.0 141.4 270.50 60.00 76.0 BP458 186817.2 8435201.0 158.1 268.50 60.00 80.0 BP459 187050.9 8435204.0 165.8 269.50 60.00 80.0 BP460 186911.7 8435201.0 163.0 270.50 60.00 80.0 BP461 186829.3 8435601.0 151.3 271.50 60.00 80.0 BP463 186930.4 8435602.0 177.2 268.50 61.00 80.0 BP464 186881.2 8435601.0 162.3 269.50 60.00 80.0 BP465 186770.4 8435605.0 146.4 269.50 60.00 80.0 BP466 187019.9 8435804.0 140.3 270.00 59.00 69.0 BP467 187069.9 8435802.0 150.1 268.50 60.00 80.0 BP468 187145.0 8434601.0 148.1 270.00 60.00 63.0 BP469 187094.2 8434601.0 148.9 270.50 60.00 80.0 BP470 187040.9 8434601.0 156.0 267.50 59.00 80.0 BP471 186820.5 8434601.0 158.8 267.50 60.00 80.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 88 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BP472 186801.1 8434702.0 179.4 265.50 60.00 80.0 BP473 186845.1 8434703.0 178.9 269.50 60.00 80.0 BP477 186890.5 8434651.0 172.6 266.50 61.00 110.0 BP478 186901.9 8434651.0 171.9 266.00 75.00 120.0 BP479 186928.6 8434751.0 139.0 284.50 60.00 150.0 BP480 187023.8 8434635.0 159.3 262.00 60.00 160.0 BP481 186997.3 8434751.0 139.2 265.00 75.00 110.0 BP482 186998.5 8434751.0 139.1 89.00 74.50 60.0 BP483 187269.7 8434951.0 149.3 265.00 59.50 150.0 BP484 187296.7 8434951.0 149.6 266.50 60.00 150.0 BP485 186959.0 8434751.0 139.0 267.50 60.00 120.0 BP486 187209.2 8435001.0 155.0 268.00 60.00 120.0 BP487 186974.2 8435102.0 138.6 265.50 57.00 170.0 BP488 187149.9 8435002.0 155.7 266.00 60.50 120.0 BP489 187261.6 8435001.0 152.7 267.00 59.00 120.0 BP490 187354.5 8435151.0 153.0 270.00 60.00 190.0 BP491 186997.2 8435352.0 179.8 85.00 60.00 100.0 BP492 187229.1 8435402.0 175.3 266.00 60.50 90.0 BP493 187246.6 8435352.0 173.0 265.00 60.00 90.0 BP494 186929.5 8435301.0 178.4 87.00 59.50 170.0 BP495 187379.2 8435152.0 150.6 266.50 59.00 190.0 BP496 186898.4 8434652.0 172.3 85.00 61.00 100.0 BP497 186865.8 8434751.0 171.0 268.00 75.00 150.0 BP498 186874.2 8434752.0 171.0 78.00 75.00 80.0 BP499 186862.5 8434671.0 178.8 85.00 70.00 150.0 BP500 187073.5 8434801.0 154.8 274.00 62.00 120.0 BP501 187138.4 8434851.0 151.9 265.00 60.00 120.0 BP502 187133.1 8434901.0 151.4 264.00 60.00 120.0 BP503 187180.1 8434901.0 150.0 264.50 59.00 190.0 BP504 187207.0 8434901.0 148.9 264.50 59.50 190.0 BP505 187158.4 8434951.0 152.5 266.50 59.50 150.0 BP506 187213.3 8434951.0 151.3 268.00 60.00 150.0 BP507 187063.6 8434701.0 153.4 266.00 60.00 130.0 BP508 187093.8 8434751.0 154.1 266.50 61.00 130.0 BP511 187117.0 8435402.0 146.8 264.50 63.50 150.0 BP512 187303.9 8435102.0 143.3 269.50 59.50 180.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 89 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH BP513 187332.3 8435102.0 142.9 260.00 60.00 170.0 BP514 186814.0 8434901.0 171.1 86.50 66.00 150.0 BP515 186719.3 8434901.0 170.3 90.00 60.00 150.0 BP516 186760.3 8435101.0 162.9 88.00 59.00 150.0 BP517 186844.8 8435201.0 162.1 84.50 60.00 150.0 BP518 186875.3 8435351.0 168.2 89.50 59.00 150.0 BP519 187300.7 8435302.0 167.4 85.00 59.00 140.0 BP520 186769.6 8434736.0 186.9 89.00 59.00 130.0 BP521 187070.7 8434755.0 155.0 85.50 60.00 120.0 BP522 186866.3 8435101.0 162.5 84.50 74.00 120.0 BP523 187093.4 8435352.0 142.5 266.00 63.00 110.0 BP524 187083.4 8435392.0 142.9 264.50 61.00 110.0 DP001 187459.3 8435202.0 145.8 0.00 90.00 31.0 DP002 187435.8 8435207.0 147.3 89.50 60.00 50.0 DP029 187506.6 8435702.0 142.2 90.00 60.00 100.0 DP034 187515.0 8435652.0 142.2 90.00 61.50 75.0 DP038 187515.2 8435602.0 141.7 90.00 59.50 70.0 DP041 187505.2 8435502.0 144.2 90.00 61.00 59.0 DP053 187490.0 8435652.0 143.3 90.00 61.00 80.0 MHT-001 187133.5 8434628.0 147.5 0.00 90.00 0.0 MHT-003 187266.2 8434759.0 144.9 319.20 25.00 201.0 MHT-004 187261.9 8434749.0 159.0 0.00 90.00 0.0 QP089 187464.7 8435303.0 144.8 270.00 60.00 100.0 QP090 187513.8 8435302.0 140.5 270.00 60.00 100.0 QP092 187467.6 8435100.0 146.8 270.00 60.00 100.0 QP093 187468.4 8435203.0 145.0 270.00 60.00 100.0 QP094 187518.7 8435203.0 143.9 270.00 60.00 100.0 QP096 187295.4 8434701.0 146.6 270.00 60.00 100.0 QP097 187247.3 8434703.0 146.6 270.00 60.00 100.0 QP131 187269.5 8434902.0 146.8 270.00 60.00 100.0 QP132 187269.3 8434852.0 146.0 270.00 60.00 82.0 QP133 187265.8 8434799.0 145.6 270.00 60.00 68.0 TP156 187517.9 8435552.0 143.0 90.00 59.00 52.0 VB07-001 187210.4 8434975.0 122.3 270.00 60.80 486.8 VB07-002 187223.1 8434773.0 142.7 270.00 66.00 492.0 VB07-003 187220.9 8435092.0 110.0 270.00 67.50 93.9

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 90 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH VB07-004 187136.3 8435299.0 114.5 248.00 62.00 328.9 VB07-005 187220.9 8435092.0 110.0 270.00 67.00 363.9 VB07-006 187173.9 8435316.0 115.0 248.00 73.00 440.8 VB07-007 187220.9 8435092.0 110.0 270.00 55.00 374.1 VB07-008 187174.7 8435316.0 115.1 0.00 90.00 498.7 VB07-009 187215.5 8435032.0 116.4 270.00 60.00 416.1 VB07-010 187203.4 8434919.0 128.0 270.00 63.00 463.0 VB07-011 187249.6 8435655.0 170.2 270.00 65.00 249.7 VB07-012 187330.0 8435555.0 162.0 270.00 65.00 398.8 VB07-013 187189.5 8434826.0 136.9 270.00 60.00 452.4 VB07-014 187326.8 8435320.0 161.3 281.50 70.00 567.4 VB07-015 186925.8 8435106.0 118.5 113.00 57.00 284.0 VB07-016 187279.5 8435653.0 169.9 270.00 65.00 303.0 VB07-017 187272.3 8435469.0 162.0 270.00 60.00 378.3 VB07-018 187295.8 8435183.0 137.7 270.00 60.00 570.5 VB07-019 186994.6 8434399.0 146.5 270.00 60.00 237.2 VB07-020 186982.5 8434499.0 153.1 270.00 60.00 261.3 VB07-021 187049.9 8434745.0 120.0 278.00 63.00 426.8 VB07-022 186998.9 8434739.0 120.0 45.00 65.00 533.6 VB07-023 187258.2 8435967.0 140.8 272.00 65.00 473.1 VB07-024 187389.1 8435646.0 151.2 270.00 61.00 362.7 VB07-025 186898.3 8434383.0 153.2 15.00 65.00 426.3 VB08-026 187416.9 8434904.0 144.9 267.20 49.20 700.5 VB08-027 187413.7 8434953.0 146.0 266.60 51.70 661.3 VB08-028 187412.9 8435002.0 146.4 268.10 52.90 647.8 VB08-029 187296.9 8435053.0 146.0 266.30 59.10 0.0 VB08-030 187296.8 8435055.0 146.3 275.10 59.60 599.1 VB08-031 187367.3 8435051.0 146.3 273.00 60.60 640.6 VB08-032 187331.8 8435054.0 146.4 273.00 58.20 632.7 VB08-033 187367.9 8435051.0 146.3 278.20 72.70 0.0 VB08-034 187369.0 8435051.0 146.3 274.70 73.20 750.0 VB08-035 187337.3 8435100.0 141.8 268.60 59.80 678.0 VB08-036 187349.2 8435155.0 143.3 274.10 60.00 657.1 VB08-037 187365.5 8435204.0 153.2 272.50 60.50 655.1 VB08-038 187349.6 8435155.0 143.3 278.30 76.30 730.7 VB08-039 187376.3 8435100.0 147.3 272.40 59.50 615.3

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 91 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH VB08-040 187377.0 8435100.0 147.3 274.70 73.70 669.1 VB08-041 187190.6 8435665.0 171.3 88.60 75.40 300.4 VB10-001 187528.9 8435955.0 138.2 274.00 62.31 550.8 VB10-002 187468.4 8435505.0 147.4 269.76 55.56 287.4 VB10-003 186748.0 8435114.0 163.5 267.00 80.08 525.7 VB10-004 187589.0 8434904.0 141.7 280.75 59.40 864.4 VB10-005 187019.6 8434457.0 148.8 268.39 61.38 410.4 VB10-006 187460.3 8435251.0 145.3 273.83 62.26 721.7 VB10-007 187330.1 8434779.0 144.4 270.00 66.00 704.5 VB10-008 187446.0 8435004.0 145.0 274.91 60.83 735.5 VB10-009 187239.0 8434593.0 148.7 270.00 60.00 669.5 VB10-010 187349.9 8435855.0 167.8 271.00 67.00 48.0 VB10-011 187275.2 8435547.0 162.4 279.41 68.45 630.5 VB10-012 187240.0 8434890.0 150.0 263.35 54.96 725.9 VB11-001 187364.6 8435054.0 146.4 290.63 50.00 596.1 VB11-002 187354.7 8435149.0 143.4 288.63 50.00 572.9 VB11-003 187271.4 8434847.0 149.2 273.63 55.00 535.0 VB11-012 187443.5 8434999.0 145.0 269.23 58.60 806.8 VB11-013 187261.3 8435702.0 169.7 271.63 67.20 388.3 VB11-014 187329.2 8434775.0 144.2 271.13 58.90 704.9 VB11-015 187508.3 8435165.0 142.6 271.63 61.00 875.9 VB12-001 187434.8 8434812.0 144.7 268.63 65.00 744.2 VB12-002 187446.6 8434901.0 144.4 268.63 58.00 750.3 VB12-003 187133.3 8434601.0 147.3 268.63 60.00 625.0 VB12-004 187257.2 8435702.0 169.7 268.63 55.00 383.4 VB12-005 187433.6 8434952.0 145.7 268.63 60.00 759.1 VB12-006 187299.4 8435737.0 169.4 269.63 55.00 475.6 VB12-007 187501.5 8435400.0 143.3 268.63 60.00 887.8 VB12-008 187289.7 8435360.0 161.9 268.63 65.00 645.9 VB12-009 187315.5 8434701.0 144.5 268.63 60.00 717.2 VB12-010 187432.9 8435610.0 145.1 266.63 60.00 751.0 VB12-011 187093.5 8434604.0 146.4 266.63 57.00 629.8 VB12-012 187466.2 8435352.0 146.0 266.63 63.00 793.7 VB12-013 187445.2 8434901.0 144.4 270.13 55.00 883.1 VB12-014 187412.0 8435757.0 149.5 266.63 60.00 754.0 VB12-015 187446.7 8434902.0 144.4 263.63 56.00 745.8

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 92 HOLE-ID EASTING NORTHING ELEV. AZIMUTH DIP DEPTH VB12-016 187262.7 8434704.0 147.3 265.63 60.00 713.5 VB12-017 187391.2 8435349.0 150.8 265.63 63.00 833.3 VB12-018 187429.9 8434849.0 144.7 265.63 58.00 177.0 VB12-019 187429.5 8434847.0 144.8 265.63 60.00 731.8 VB12-020 187359.6 8435852.0 167.3 265.63 65.00 611.9 VB12-021 187378.8 8435954.0 149.9 266.70 65.20 602.9 VB12-022 187179.3 8434453.0 153.3 265.64 56.59 647.9 VB12-023 187371.0 8435801.0 161.3 264.45 60.03 650.9 VB12-024 187094.7 8434482.0 149.8 268.63 60.00 460.1 VB12-025 187344.7 8435656.0 158.6 260.63 60.00 650.6 VB12-026 187066.8 8434393.0 144.8 268.63 60.00 378.9 VB12-027 187259.7 8435717.0 169.8 290.63 55.00 434.8 VB15-001 187431.0 8434480.0 147.0 268.30 75.81 455.5 VB15-001W1 187431.0 8434480.0 147.0 268.30 75.81 831.8 VB15-001W2 187431.0 8434480.0 147.0 268.30 75.81 746.0 VB15-002 187277.0 8434703.0 147.3 266.07 76.19 446.3 VB15-002W1 187277.0 8434703.0 147.3 266.07 76.19 705.0 VB16-002 187195.0 8434849.0 134.8 328.60 64.00 463.9 VB17-001 187094.0 8435292.0 161.5 184.60 55.00 162.0 VB17-002 187194.0 8434848.0 134.8 330.60 64.00 476.0 VB17-003 187091.0 8435290.0 161.5 188.20 55.00 533.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 93 Source: Tetra Tech, Inc. (2019) Figure 10-1: Drillhole Location Map Batman Deposit to VB18-003

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 94 Source: Tetra Tech, Inc. (2019) Figure 10-2: Batman Cross-section 1

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 95 Source: Tetra Tech, Inc. (2019) Figure 10-3: Batman Cross-section 2

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 96 Source: Tetra Tech, Inc. (2019) Figure 10-4: Batman Cross-section 3

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 97 Source: Tetra Tech, Inc. (2019) Figure 10-5: Batman Cross-section 4

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 98 Source: Tetra Tech (2019) Figure 10-6: Batman Cross-section 5

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 99 10.2 Summary History of Quigleys Drilling 1975-2011 Table 10-4 shows the Quigleys deposit drilling history. Quigleys was mined from 1982 to 1987 during which the largest amount of drilling was percussion type used for ore grade control. Table 10-5 lists the drillholes used for the current estimate the Quigleys deposit. Figure 10-7 is an isometric view of the Quigleys drilling database with the position of the A-A’ section at 8,438,200 north shown. Figure 10-8 shows the A-A’ cross-sectional view of the deposit looking north; with the mineralized zone dipping to the west with the orientation of the drillholes dipping to the east. Relevant intervals of mineralization are contained within blanket-like zones which are modeled with 3-D wireframes for resource estimation. These zones are shown in Figure 14-14. The mineralized zones have been defined by wireframes which are used to constrain the higher grades for the resource estimation. The majority of drilling has been angled so as to be approximately perpendicular to the mineralized core. This orientation more accurately transects the true thickness of the mineralization. While there are random high grade intercepts outside of the core, the majority of higher grade mineralization resides within the defined zones. In 2011, Vista explored the potential for a deeper deposit with three diamond drillholes, each over 350 meters in depth. Table 10-4: Quigleys Deposit Drilling History Date Reference Holes (#) Percussion (m) Diamond (m) RC (m) 1975 Australian Ores and Minerals/Esso 2 200 1981 Arafura Mining Corp / CRA 14 676.5 1982-1987 Pacific Gold Mines NL (Small Scale Mining) 603 41,429 9710 4,013 1989 Pacific Gold Mines 9 501 202 2011 Vista 3 1,090 1988-2017 Quigleys Total 631 41,930 11,878 4,013 Table 10-5: Quigleys Drillhole Details HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP DDH1 173 189529.1 8438240 186 108 -60 DDH2 105.81 189621.7 8438288 170 0 -90 MT01 82.54 189693.1 8438406 175 102 -60 MT02 54.04 189648.4 8438198 197.7 0 -90 MT02A 17.78 189648 8438196 197.8 0 -90 MT03 73.74 189623.3 8438159 194.5 0 -90 MT03A 24.25 189624.3 8438159 194.5 110 -60 MT04 35.8 189736.3 8438397 178 0 -90 MT05 36.9 189734 8438305 205.8 111 -60

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 100 HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP MT06 53.73 189654.6 8438334 176.5 0 -90 MT07 23.7 189793.6 8438649 169.6 0 -90 MT08 23.44 189854.5 8438754 167 0 -90 MT09 49 189748.5 8438647 158 0 -90 MT10 49.15 189860 8438851 157 98 -60 MT11 50.66 189808 8438775 153 113 -60 MT12 34.85 189752.4 8438547 168 0 -90 MT13 37.75 189630.5 8438283 161 126 -50 MT14 29.21 189635.7 8438042 148.9 86 -45 MT15 24.5 189673.3 8438045 163.4 0 -90 MT16 35.5 189636.1 8438045 149.2 0 -60 MT17 41 189618.5 8438196 197.4 90 -70 MT18 49.6 189618.3 8438196 197.4 0 -90 MT19 14.5 189647.9 8438201 197.5 90 -60 MT20 33 189645 8438201 197.4 270 -70 MT21 35.3 189706.8 8438347 199 0 -90 MT22 50 189706.8 8438347 199 270 -70 MT24 31.5 189755.4 8438553 168.9 90 -60 MT25 20.5 189756.2 8438523 169.6 0 -90 MT26 17.5 189764.7 8438503 169.3 0 -90 MT27 17 189795.7 8438654 169.9 90 -60 MT28 40 189795.7 8438654 169.9 270 -70 MT29 36.2 189751.5 8438654 158.8 90 -60 MT30 22.5 189793.1 8438663 179.4 0 -90 MT31 14.5 189789.8 8438605 168.2 0 -90 MT32 20.5 189790.4 8438629 168.6 0 -90 MT33 20.6 189864.6 8438755 169 0 -90 MT34 17.5 189870.1 8438774 160.8 0 -90 MT35 19.6 189874.4 8438799 159.5 0 -90 MT36 23.3 189877 8438823 160 0 -90 MT37 40.2 189882.4 8438847 161 0 -90 MT38 13 189893.8 8438848 163.5 0 -90 MT39 19.5 189732.7 8438347 199.1 0 -90 MT40 27.7 189732.7 8438347 199.1 90 -60 MT41 33 189732.7 8438347 199 270 -60 MT42 15 189756.8 8438347 198.8 0 -90

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 101 HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP PRP017 30 189458.6 8437854 158 99 -60 PRP018 30 189447.8 8437774 159.6 0 -90 PRP019 29.5 189454.9 8437830 162.5 98 -59 QD001 196.5 188989.8 8437999 143.7 42 -47 QD002 320.5 189053.1 8437801 134 60 -66 QD003 108.1 189448 8438016 146.1 13 -50 QD004 295.8 189447.1 8438013 146 341 -50 QD005 90 189577.9 8438230 195.92 92 -61 QD006 100 189519.7 8438232 185.59 0 -90 QD007 119.5 189535.5 8438308 163.4 110 -70 QD008 130 189422.4 8438202 163.53 90 -90 QD009 139 189431.6 8438258 166.4 126 -69 QD010 140 189432.1 8438147 146.67 90 -90 QD011 250 189470.7 8438070 160.92 94 -60 QD012 251.9 189493.5 8437942 142.8 90 -60 QD013 251.56 189491.6 8437887 150.8 94 -60 QD014 250 189491.6 8437985 143.77 92 -60 QD015 251.81 189515.5 8438306 163.1 92 -59 QD016 251.7 189570.9 8438410 155.08 88 -61 QD017 180.5 189417.8 8438007 145.12 88 -60 QD019 185.81 189410 8438307 153.13 96 -60 QD021 260.5 189216.7 8438308 135.19 94 -61 QD022 251.7 189221.6 8438003 133.24 92 -60 QD024 150 189414.5 8438206 167.02 90 -60 QD025 228 189222.5 8438203 134.64 90 -60.2 QD026 249.5 189186.8 8438104 133.21 90 -60 QD027 249 189317.7 8438307 141.79 88 -60 QD028 180.5 189316.6 8438106 158.88 96 -60 QD029 245.5 189318.3 8438007 150.84 94 -60 QD030 216.5 189276.6 8438212 139.11 92 -60 QD031 249.4 189314.2 8437965 139.7 98 -60 QD035 123.3 189359 8437906 131.65 0 -60 QD036 111.6 189310.8 8437919 135.8 0 -60 QD037 114.6 189270.6 8437895 134.13 0 -60 QD038 111.61 189167.5 8437905 132.62 0 -60 QNE001 30 189881.3 8439055 149 88 -60

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 102 HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP QNE002 30 189876.5 8439074 147.3 88 -60 QNE003 25 189872.8 8439093 146.4 86 -60 QNE004 30 189863.7 8439115 145.4 88 -60 QNE005 25 189864.3 8439132 144.9 88 -60 QNE006 30 189851.4 8439155 143.7 90 -60 QNE007 40 189840.2 8439172 141.7 87 -60 QNE008 30 189853.6 8439171 143.2 90 -60 QNE009 40 189835.3 8439200 140.5 83 -60 QNE010 29.5 189843 8439199 140.3 83 -60 QNE011 30 189836 8439218 140.7 93 -60 QP001 50 188967.3 8438006 145.5 47 -60 QP002 50 189020.3 8438009 143.7 47 -60 QP003 50 189074.3 8438012 139.3 47 -60 QP004 74 189572.5 8438262 182.2 90 -60 QP005 62 189602.5 8438260 182.3 90 -60 QP006 100 189525.4 8438233 185.4 90 -60 QP007 80 189578.1 8438231 195.8 90 -60 QP008 74 189572.4 8438201 189.4 90 -60 QP009 73 189582.2 8438182 186.7 0 -90 QP010 70 189574 8438153 180.4 90 -90 QP011 78 189548.2 8438131 175.8 90 -60 QP012 60 189599.8 8438131 180.3 90 -60 QP013 64 189594.3 8438081 155.1 90 -60 QP014 48 189638.6 8438081 158.7 90 -60 QP015 71 189598.2 8438046 147.4 90 -60 QP016 40 189647.8 8438045 154.6 90 -60 QP017 70 189617.2 8438006 146 90 -60 QP018 50 189642.7 8438007 150.1 90 -60 QP019 56 189669.7 8438007 160 90 -60 QP020 60 189691.6 8438006 167.6 90 -60 QP021 62 189633.4 8437982 155.9 90 -60 QP022 62 189658 8437981 162.6 90 -60 QP023 50 189644.4 8437933 163.7 90 -60 QP024 55 189663.5 8437931 173.3 90 -60 QP025 80 189571.6 8438202 189.5 0 -65 QP026 74 189568.7 8438259 182.6 180 -65

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 103 HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP QP027 60 189628.2 8438255 181.4 90 -60 QP028 56 189552.8 8438328 155.9 90 -60 QP029 60 189585 8438331 152.1 90 -60 QP030 60 189676.8 8438052 165.57 70 -60 QP031 60 189677.5 8438129 183.81 90 -60 QP033 60 189625.8 8438240 181.28 130 -65 QP035 60 189729.1 8438331 197.58 0 -90 QP036 39 189577.9 8438230 195.92 91 -61 QP037 75 189510.9 8438170 157.5 90 -90 QP038 54.41 189519.7 8438232 185.59 0 -90 QP039 69 189535.5 8438308 163.4 110 -70 QP041 60 189422.4 8438202 163.53 90 -90 QP042 68 189431.6 8438258 166.4 126 -69 QP043 74 189817.2 8439072 143.71 90 -60 QP045 96 189764.8 8438725 160.13 118 -65 QP046 66 189717.8 8438658 152.9 90 -60 QP047 60 189762.2 8438657 164.43 90 -60 QP048 50 189781.7 8438657 164.43 86 -60 QP049 50 189816.7 8438652 170.1 270 -60 QP050 60 189693.9 8438580 153.71 90 -60 QP051 80 189629.7 8438406 174.4 90 -60 QP052 60 189717.7 8438397 179.27 90 -60 QP053 50 189749.7 8438407 177.85 90 -60 QP054 50 189778.6 8438411 181.02 90 -60 QP055 60 189629.4 8438245 181.34 180 -60 QP056 60 189627.3 8438212 174.22 0 -60 QP057 50 189629.9 8438183 173.22 0 -60 QP058 50 189637.6 8438153 173.61 0 -60 QP059 60 189632 8438254 181.47 180 -60 QP060 88 189431.8 8438254 166.39 170 -60 QP061 46 189431.5 8438245 167.68 0 -90 QP062 94 189426.4 8438224 165.48 0 -60 QP063 51 189510.6 8438170 157.73 90 -60 QP064 60 189494.4 8438173 155.19 0 -90 QP065 94 189544.3 8438257 182.38 90 -60 QP066 90 189516.2 8438237 185.4 0 -60

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 104 HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP QP067 40 189497.1 8438259 184.68 180 -60 QP068 80 189572.4 8438231 195.59 0 -90 QP069 100 189571.5 8438223 196.14 0 -60 QP070 60 189571.3 8438200 189.24 0 -90 QP071 64 189572.9 8438155 180.72 0 -60 QP072 94 189567.8 8438146 178.47 0 -60 QP073 64 189567.9 8438145 178.26 0 -90 QP074 77 189546.6 8438131 176.3 0 -90 QP075 88 189515.1 8438131 170.4 0 -90 QP076 90 189517.3 8438119 171.68 0 -60 QP077 97 189432.9 8438151 147.29 0 -90 QP078 112 189515.8 8438108 171.87 0 -90 QP079 70 189539.6 8438221 186.21 0 -90 QP080 112 189512.4 8438254 184.6 0 -90 QP081 97 189538.4 8438257 182.81 0 -90 QP082 48 189651.9 8438281 181.7 0 -90 QP083 54 189655.1 8438307 179.7 162 -89 QP084 60 189697.9 8438183 200.23 354 -60 QP085 60 189697.9 8438220 199.99 180 -60 QP086 34 189649 8438267 181.9 85 -50 QP134 100 189718.9 8437206 134.53 270 -59 QP135 102 189767.5 8437203 133.4 276 -60 QP136 102 189818.1 8437202 130.64 268 -60 QP137 102 189813.8 8437407 135.3 96 -60 QP138 102 189717 8437406 144.67 90 -63 QP139 102 189667.6 8437507 133.53 88 -60.5 QP140 102 189621.4 8437506 132.16 92 -60 QP141 100 189691.3 8437626 149.28 90 -61 QP142 100 189645 8437627 147.6 90 -59.5 QP143 100 189597.9 8437626 143.44 88 -61 QP144 100 189767.5 8437405 141.43 92 -59.9 QP145 100 188870 8437801 136.24 92 -60.4 QP146 100 188917.3 8437804 135.96 90 -59.8 QP147 100 188962 8437800 135.65 90 -60 QP148 100 189021.2 8437804 133.88 90 -61 QP149 100 189127 8437767 132.06 90 -61

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 105 HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP QP150 100 188816.5 8438007 139.51 92 -60 QP151 100 188867.3 8438006 139.87 92 -60.5 QP152 100 188966.1 8438004 145.37 90 -61 QP153 100 188919.9 8438004 139.12 90 -60.2 QP154 100 189222.5 8438203 134.64 90 -60.2 QP155 100 189417.5 8438406 144.28 90 -60.8 QP156 100 189317.3 8438407 139.62 90 -60 QP170 100 189690.4 8437677 157.11 92 -60 QP171 97 189647.8 8437678 146.37 90 -60 QP172 80 189721.4 8437721 170.85 92 -65 QP173 80 189695 8437721 166.73 90 -60 QP174 80 189669.4 8437724 159.03 92 -60 QP175 80 189649.5 8437728 151.5 90 -59.5 QP176 80 189698.5 8437778 181 92 -60 QP177 80 189587.1 8437776 158.77 92 -60.5 QP178 80 189723.5 8437827 191.67 90 -60 QP179 80 189694.4 8437829 193.81 104 -60 QP180 80 189667 8437829 190.58 90 -59 QP181 80 189642 8437832 184.35 92 -59 QP182 80 189618 8437835 176.95 92 -61 QP183 80 189595.4 8437834 168.85 92 -61 QP184 100 189596.6 8437881 161.4 92 -60 QP185 80 189699.2 8437930 181.86 94 -60 QP186 80 189623.6 8437936 155.12 88 -60 QP187 60 189641 8438081 158.25 92 -60 QP188 80 189721.5 8437876 193.02 94 -60 QP189 80 189630 8437726 146.24 90 -61 QP190 80 189603.3 8437727 146.79 90 -61 QP191 100 189594.2 8437683 140.86 94 -60 QP192 100 189568.8 8437505 135.54 88 -60 QP193 100 189166.6 8437780 131.68 92 -60 QP194 100 189276.6 8438212 139.11 92 -60 QP195 100 189328.8 8438209 154.87 90 -60 QP196 100 189370.4 8438211 169.99 92 -60 QP197 100 189012.9 8438204 148.84 92 -60 QP198 97 189165.9 8438207 141.52 94 -59.5

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 106 HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP QP199 100 189119.4 8438204 147.53 94 -60 QP205 100 189068.2 8438203 155.01 94 -60.5 QP206 100 189170.4 8438407 154.7 94 -60 QP207 100 189070.4 8438407 151.3 96 -58 QP208 100 189117.9 8438404 151.74 96 -59 QP209 100 189628.9 8437990 153.47 94 -58.5 QP210 100 189599.4 8437989 146.41 94 -60 QP211 100 189561.1 8437989 142.66 92 -59.5 QP212 100 189568.5 8437964 143.69 90 -60 QP213 100 189620.5 8437960 154.68 90 -60 QP214 100 189593.5 8437963 147.43 96 -59.5 QP215 100 189594.8 8437939 146.31 94 -60 QP216 100 189617.1 8437915 150.72 94 -59 QP217 100 189575.1 8437943 144.52 94 -60 QP218 100 189558.8 8437909 148.98 94 -59.5 QP219 100 189567.7 8437888 151.8 92 -60 QP237 100 189595.9 8437804 167.79 94 -58.5 QP238 100 189568.1 8437803 157.68 94 -61 QP239 100 189560.2 8437826 155.45 98 -59.5 QP240 100 189590.9 8437856 161.63 90 -59.5 QP241 100 189569 8437871 149.53 90 -60 QP242 100 189585.4 8437916 149.26 90 -58.5 QP253 100 189069.2 8438312 163.59 92 -60 QP254 100 189116 8438308 152.37 88 -57 QP255 100 189662.6 8438037 159.66 92 -59 QP256 106 189665.7 8438074 164.97 94 -59.5 QP257 100 189710.4 8438015 166.56 92 -59 QP258 100 189663.7 8438112 176.49 92 -59 QP259 100 189619.4 8438114 173.34 90 -57 QP260 100 189569 8438153 176.65 92 -59 QP261 100 189569.6 8438123 171.28 94 -59.5 QP262 112 189516.6 8438105 170.03 94 -58.5 QP263 100 189513.8 8438142 167.97 100 -58.5 QP264 100 189468.5 8438103 161.54 92 -59 QP265 100 189470.7 8438070 160.92 94 -60 QP266 100 189518.1 8438066 156.18 88 -60

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 107 HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP QP267 100 189568.2 8438069 148.06 90 -60 QP268 100 189613.2 8438074 152.05 88 -60 QP269 100 189643.5 8437961 161.94 90 -60 QP270 100 189367.1 8438006 153.55 92 -60 QP271 106 189318.3 8438007 150.84 94 -60 QP272 68 189466.7 8438007 146.8 92 -60 QP273 106 189515.4 8438007 144.93 92 -60 QP274 100 189491.6 8437985 143.77 92 -60 QP275 100 189541.7 8437988 140.91 94 -60 QP276 100 189542.9 8438012 141.18 94 -60 QP277 100 189565.4 8438015 142.86 94 -61 QP278 106 189613 8438038 147.22 90 -60 QP279 106 189592.5 8438016 145.31 92 -60 QP280 100 189566.1 8438035 143.22 90 -60 QP281 100 189542 8437943 142.35 94 -60 QP282 100 189493.5 8437942 142.8 90 -60 QP283 100 189441.5 8437941 137.32 90 -61 QP284 112 189491.6 8437887 150.8 94 -60 QP285 100 189443.5 8437885 148.82 90 -60 QP286 100 189298.1 8437882 135.97 90 -60 QP287 100 189194.8 8437883 137.89 92 -59 QP288 58 189146.7 8437881 132.5 90 -59 QP289 100 188917.4 8437916 138.68 88 -62 QP290 105 188862.9 8437907 137.21 92 -61 QP291 100 188817.9 8437905 137.03 92 -61 QP292 100 188765.8 8437905 140.29 90 -61 QP293 100 188717 8437906 140.03 88 -61 QP294 106 188767.9 8438006 139.49 94 -60 QP295 100 188722.3 8438006 141 94 -60 QP296 100 189247.4 8437883 134.08 94 -60 QP297 100 188825.7 8438110 136.21 90 -60 QP298 100 188914.8 8438203 135.35 94 -59 QP299 100 189121 8438509 144.05 90 -60 QP300 100 189542.4 8437827 148.9 88 -60 QP301 100 189537 8437773 142.6 90 -60 QP302 100 189549.6 8437730 138.7 88 -59

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 108 HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP QP303 100 189578.2 8437728 142.39 88 -60 QP304 106 189619.4 8437680 140.59 92 -58 QP305 100 189570.9 8437678 138.31 88 -60 QP306 100 189525.8 8437684 134.13 88 -60 QP307 100 189549.5 8437625 134.88 88 -59.5 QP308 100 189815.1 8437511 139.99 88 -60 QP309 100 189764.9 8437504 141.5 90 -58 QP310 100 189713.4 8437508 140.09 86 -60 QP311 100 189738.7 8437636 158.74 86 -59 QP312 100 189739.3 8437680 166.39 90 -58 QP313 100 189747.6 8437721 166.88 88 -59 QP314 100 189623.8 8437855 176.33 86 -59 QP315 100 189541.5 8437888 145.81 90 -60 QP316 112 189488.9 8438138 166.5 86 -59 QP317 100 189537.4 8438144 170.04 90 -61 QP318 100 189538.1 8438115 171.87 94 -60 QP319 100 189595.6 8438120 173.9 94 -59 QP320 100 189636.8 8438114 174.2 88 -54 QP321 100 189686.9 8438112 178.54 88 -58 QP322 100 189688.9 8438074 173.11 90 -58 QP323 100 189732 8438015 161.07 88 -55 QP324 100 189756.7 8438012 153.96 92 -59 QP325 100 189538 8438071 156.04 90 -59 QP326 100 189603.2 8438154 190.35 90 -59 QP327 100 189585.8 8438196 192.38 92 -59 QP328 100 189642.7 8438149 174.87 90 -59 QP329 106 189630.8 8438197 174.68 86 -58 QP330 100 189069.1 8438508 142.15 92 -60 QP331 100 189021 8438505 141.37 90 -60 QP332 100 188968.9 8438408 140.06 90 -60 QP333 104 189166.3 8438103 133.24 92 -60 QP334 100 189119.8 8438106 135.09 90 -59 QP335 100 189067.4 8438101 135.41 90 -60 QP336 100 189027.2 8438096 136.3 94 -60 QP337 100 189013.5 8437904 137.96 90 -60 QP338 100 188966.3 8437905 138.77 92 -61

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 109 HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP QP339 100 189061.8 8437904 136.46 90 -60 QP340 100 189116.2 8438006 137.09 90 -61 QP341 100 189068.9 8438008 139.53 88 -61 QP342 100 189026 8438013 143.43 94 -61 QP343 100 189165.9 8437999 134.94 94 -61 QP344 100 189139.4 8437880 132.59 90 -60 QP345 100 189216.7 8438308 135.19 94 -61 QP346 100 189266.9 8438307 137.51 94 -60 QP347 100 189471.2 8438413 144.96 90 -61 QP348 100 189367 8438403 140.76 90 -61 QP349 100 189271 8438409 137.4 94 -60 QP350 100 189191.7 8438153 134.24 94 -60 QP351 100 189186.8 8438104 133.21 90 -60 QP352 100 189140.9 8438105 134.38 88 -60 QP353 100 189142 8438153 135.45 88 -60 QP354 106 189185.9 8438053 133.44 92 -60 QP355 100 189139.7 8438054 134.67 92 -61 QP356 100 189221.6 8438003 133.24 92 -60 QP357 108 189137.9 8437951 133.64 90 -60 QP358 100 189184.4 8437953 132.82 84 -61 QP359 100 189120.8 8437896 132.4 90 -60 QP360 100 189673.3 8437879 184.83 90 -60 QP361 100 189711.2 8437953 177.87 90 -59 QP362 100 189690.9 8437958 177.44 92 -58.5 QP363 100 189661.8 8437911 174.1 90 -59 QP364 100 189669.7 8437955 173.28 88 -58 QP365 100 189713.5 8438072 169.54 94 -60 QP366 100 189669.1 8437982 166.94 90 -60 QP367 100 189653.1 8438017 153.53 94 -60 QP368 100 189574 8437625 138.91 100 -59 QP369 98 189524.7 8437627 134.1 94 -60 QP370 99 189446.7 8437773 158.78 90 -61 QP371 100 189487.8 8437768 148.71 90 -61 QP372 100 189504.4 8437725 140.78 92 -61 QP373 100 189495.9 8437826 149.66 90 -59 QP374 100 189515.5 8438306 163.1 92 -59

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 110 HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP QP375 100 189566.4 8438307 163.41 94 -61 QP376 100 189605.9 8438307 156.15 92 -61 QP377 100 189471.1 8438315 152.85 96 -60 QP378 98 189410 8438307 153.13 96 -60 QP379 100 189364.4 8438303 151.68 88 -61 QP380 100.11 189317.7 8438307 141.79 88 -60 QP381 98 189167.8 8438308 140.75 90 -61 QP382 100 189020.7 8438308 164.19 92 -61 QP383 98 188968.4 8438304 148.84 94 -61 QP384 100 188969 8438206 142.98 92 -61 QP385 100 189018.7 8438416 144.94 92 -61 QP386 100 189316.6 8438106 158.88 96 -60 QP387 100 189269.9 8438106 154.74 94 -60 QP388 100 189414.5 8438206 167.02 90 -60 QP389 100 189411.8 8438254 174 92 -60 QP390 100 189640.5 8438255 181.07 90 -57 QP391 100 189691.3 8438252 182.25 90 -58 QP392 100 189640.5 8437780 170.87 86 -57 QP393 100 189472.5 8438255 183.12 86 -57 QP394 106 189519.8 8438257 182.33 90 -58 QP395 100 189540.6 8438207 182.81 94 -59 QP396 100 189497.3 8438224 183.78 88 -60 QP397 106 189591.8 8438261 182.34 90 -58 QP398 100 189661.1 8438300 178.96 94 -59 QP399 100 189675.4 8438197 197.72 90 -59 QP400 100 189669.2 8438416 175.52 90 -58 QP401 100 189765.3 8438304 208.96 90 -59 QP402 100 189765.7 8438351 199.1 92 -58 QP403 100 189728.2 8438314 196.01 102 -59 QP404 100 189714.7 8438353 200.3 92 -59 QP405 100 189765 8438407 181.81 92 -59 QP406 100 189766.2 8438452 170.63 90 -58 QP407 100 189720.9 8438398 178.63 92 -60 QP408 100 189719.3 8438455 156.24 96 -59 QP420 100 189365.4 8438251 165.78 84 -51 QP421 100 189369.1 8438102 158.5 94 -60

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 111 HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP QP422 100 189420.1 8438103 143.77 88 -61 QP423 104 189217.5 8438105 143.06 88 -60 QP424 99 189222.3 8438408 141.7 94 -60 QP425 100 189417.8 8438007 145.12 88 -60 QP426 101 189350.7 8437879 140.69 88 -61 QP427 100 189669.2 8438510 151.05 92 -61 QP428 101 189621.3 8438513 152.93 92 -60 QP429 100 189571.9 8438355 149.93 88 -60 QP430 100 189570.9 8438410 155.08 88 -61 QP431 100 189512.8 8438357 149.58 90 -60 QP432 100 189268.8 8437997 140.04 94 -60 QP433 103 189232.7 8437956 132.27 90 -60 QP434 100 189469.8 8438358 148.27 98 -60 QP435 100 189611.9 8438374 165.57 92 -60.5 QP436 100 189668 8438355 185.9 92 -60 QP437 100 189627.3 8438415 169.93 96 -60 QP438 100 189469.1 8438464 142.8 92 -61 QP439 100 189619.9 8438462 162.12 88 -60 QP440 100 189670.5 8438458 162.02 91 -60.5 QP441 100 189717.5 8438505 161.56 94 -61 QP442 100 189764.6 8438508 159.96 94 -61 QP443 104 189765.9 8438559 169.01 90 -60 QP444 100 189819.2 8438807 154.21 90 -60 QP445 100 189821 8438857 151.71 90 -60 QP446 100 189763.7 8438858 153.2 90 -60 QP447 100 189069.6 8437513 139.26 92 -61 QP448 100 189119.4 8437511 138.99 94 -61.5 QP449 104 189169.1 8437510 137.85 84 -61.5 QP450 100 189168.9 8437885 132.73 90 -60 QP451 100 189219.1 8437884 136.28 90 -60 QP452 108 189167.5 8437834 132.22 90 -60 QP453 100 188871.5 8438105 135.2 94 -61 QP454 100 188965.1 8438097 134.2 88 -61 QP455 100 189520.1 8438462 145.54 92 -61 QP456 100 189533.3 8438418 150.3 88 -60 QP457 100 189569.6 8438462 153.3 88 -60

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 112 HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP QP458 100 189617.9 8438557 147.31 88 -62 QP459 100 189669.9 8438557 148.28 90 -60 QP460 104 189716 8438559 159.23 90 -60 QP461 104 189815.9 8438708 164.1 90 -60 QP462 100 189715.7 8438749 160.05 92 -60 QP463 100 189325.6 8437607 132.6 94 -60.5 QP464 100 189267 8437604 133.65 92 -61 QP465 100 189214.3 8437606 134.45 92 -61 QP466 100 189163.6 8437604 138.44 92 -59 QP467 100 189140.6 8437606 139.5 94 -61 QP468 100 189401.4 8437881 146.41 92 -60.5 QP469 100 189219 8437833 138.45 90 -60 QP470 100 189266 8437830 147.58 84 -61 QP471 100 189314.1 8437830 150.54 92 -59 QP472 100 189415.8 8437828 160.13 94 -60 QP473 100 189370.6 8437828 151.24 94 -61 QP474 100 189410.5 8437726 141.98 94 -60 QP475 100 189360.2 8437729 139.21 92 -59.5 QP476 100 189313.9 8437728 146.89 92 -60 QP477 100 189262.1 8437733 136.04 98 -59 QP478 100 189217.6 8437733 132.78 94 -60 QP479 100 189166.2 8437736 131.83 92 -58 QP510 100 189219.5 8437511 136.08 94 -61 QP511 100 189319.7 8437511 133.65 94 -61 QP512 100 189269.2 8437512 134.61 92 -61.5 QP513 100 189370.4 8437513 132.93 94 -61.5 QP514 100 189417.9 8437507 132.41 90 -60 QP515 100 189443.5 8437505 131.79 0 -90 QP516 100 189518.2 8437507 130.25 96 -61.5 QP517 100 189469.1 8437602 138.29 92 -61.5 QP518 81 189377.5 8437603 131.18 90 -60 QP519 100 189421.9 8437600 129.68 92 -60 QP520 105 189671.4 8438657 148.43 92 -60 QP521 100 189719.1 8438658 151.56 92 -57 QP522 100 189716.8 8438705 151.86 98 -59 QP523 100 189765.7 8438710 160.44 94 -61

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 113 HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP QP524 100 189670.8 8438606 150.09 96 -59 QP525 100 189718.3 8438607 155.59 96 -62 QP526 100 189767.7 8438605 166.26 92 -59 QP527 100 189817.6 8438606 175.99 94 -59 QP528 100 189818.3 8438657 169 90 -59 QP529 100 189118.8 8437837 132.43 90 -61 QP530 100 189869 8438706 168.05 91 -59 QP531 100 189818.9 8438752 151.83 88 -61 QP532 100 189773.2 8438761 152.88 90 -61 QP533 101 189769.8 8438805 149.38 92 -61 QP534 100 189713.6 8438806 152.33 92 -60 QP535 100 189873.8 8438902 147.52 90 -59 QP536 100 189882 8438809 142.23 104 -59 QP537 100 189893.2 8438852 141.52 94 -58 QP538 100 189823.3 8438907 146.43 98 -59 QP539 100 189921 8438909 146.14 94 -60 QP540 100 189910.6 8439009 153.4 92 -58 QP541 100 189866.7 8439003 149.15 98 -58 QP542 100 189813.9 8439004 144.61 92 -60 QP543 100 189813.6 8439108 142.22 90 -60 QP544 100 189314.2 8437965 139.7 98 -60 QP545 100 189363.1 8437957 142.81 96 -60 QP546 100 189864.7 8439108 145.4 92 -58 QP547 100 189914.3 8439108 145.07 94 -60 QP548 100 189915.5 8439208 139.34 92 -60 QP549 100 189866 8439206 140.59 86 -59 QP550 100 187121.5 8437020 173.24 0 -90 QP551 100 187067.9 8437024 177.06 0 -90 QP552 100 187167.7 8437224 175.01 0 -90 QP553 100 187116.5 8437224 167.15 0 -90 QP554 100 189215.8 8438608 164.4 0 -90 QP555 100 189167 8438607 150.8 90 -61 QP556 100 189170.2 8438512 149.9 92 -60 QP557 100 189219.3 8438509 146.18 92 -60 QP558 100 189367.1 8438805 154.97 91 -60 QP559 100 189413.3 8438807 158.06 92 -60

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 114 HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP QP560 100 189310.3 8438701 156.12 94 -60 QP561 100 189360.3 8438701 154.97 92 -59.5 QP562 100 189366.5 8438904 148.38 90 -60 QP563 100 189417.6 8438904 150.63 94 -60.5 QP564 100 189465.2 8438906 148.65 98 -60 QP565 100 189913.4 8439306 142.35 88 -59 QP566 100 189463.8 8439002 153.88 90 -59 QP567 100 189415.5 8439003 151.37 86 -60 QP568 100 189163.3 8437672 131.49 92 -60 QP569 92 189212.8 8437670 130.5 94 -60 QP570 100 189264.8 8437668 131.46 90 -58 QP571 100 189312.4 8437666 131.16 92 -59 QP572 100 189363.8 8437664 132.78 94 -60 QP573 100 189412.9 8437662 136.21 92 -60 QP574 100 189462 8437661 140.38 92 -60 QP575 100 189391.8 8437760 139.34 88 -60 QP576 100 189339.8 8437762 140.56 94 -60 QP577 100 189294 8437765 143.64 90 -60 QP578 100 189241.4 8437767 147.3 90 -60 QP579 115 189347 8438054 165.74 92 -59 QP580 115 189297.4 8438052 154.07 92 -59 QP581 110 189241.8 8438056 145 90 -59 QP582 110 189392.1 8438054 152.82 88 -60 QP583 110 189454.9 8438055 154.77 90 -60 QP584 110 189344.8 8438155 152.69 90 -59 QP585 115 189389.4 8438155 157.5 88 -59 QP586 110 189440.4 8438156 147.58 90 -61 QP588 100 189244.4 8438154 150.45 94 -60 QP589 100 189037.7 8437705 133.37 70 -69 QP590 100 189043.9 8437699 133.17 114 -70 QP591 100 189034.8 8437944 138.14 94 -60 QP592 100 189036.6 8438049 132.75 94 -57 QP593 100 189090.2 8438155 141.37 84 -60 QP594 100 189277.3 8438255 139.83 88 -59 QP595 100 189318 8438256 151.87 88 -59 QP596 100 189821.3 8438561 180.8 86 -58

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 115 HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP QP597 100 189811.4 8438517 182.51 86 -58 QP598 100 189814.8 8438454 159.82 88 -57 QP599 100 189809.3 8438394 183.85 90 -60 QP600 100 189814.1 8438352 195.2 90 -59 QP601 100 189814.9 8438302 199 94 -60 QP602 100 189773.4 8438265 197.4 94 -60 QP603 106 189713.6 8438207 200.22 90 -59 QP604 100 189707.3 8438163 195.82 90 -57 QP605 100 189470 8438173 150.17 50 -60 QP606 100 189465 8437944 140.62 0 -59 QP607 100 189415.6 8437957 139.79 0 -60 QP608 100 189362.7 8437931 138.6 2 -58 QP609 100 189312.8 8437940 137.84 4 -59 QP610 100 189270.3 8437918 138.65 0 -60 QP611 100 189218.3 8437894 138.48 6 -59 QP612 100 189118.2 8437902 132.61 6 -57 QP613 60 189413.4 8437939 139 0 -60 QP614 59 189359 8437906 131.65 0 -60 QP615 60 189310.8 8437919 135.8 0 -60 QP616 60 189270.6 8437895 134.13 0 -60 QP617 60 189167.5 8437905 132.62 0 -60 QP618 100 189817.8 8438953 145.3 92 -59 QP619 100 189791.7 8438952 144.5 92 -60 QP620 100 189791.6 8439003 144.42 90 -60 QP621 100 189840.9 8439098 143.51 90 -59 QP622 100 189814.5 8439052 143.1 90 -59 QP623 100 189839.6 8439109 142.97 90 -59 QP624 100 189865.4 8439162 144.22 92 -58 QP625 100 189839.4 8439159 141.71 90 -60 QP626 100 189838.8 8439207 138.86 91 -58 QP627 100 189117.9 8437928 132.96 1 -59.5 QP628 100 189167.7 8437928 131.69 2 -59 QP629 100 189216.3 8437951 132.22 2 -59 QP630 100 189823.1 8438003 151.5 90 -60 QP631 100 189873.1 8438003 149 88 -59 QP632 100 189923.1 8438003 147.5 88 -60

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 116 HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP QP633 100 189973.1 8438003 145 92 -61 QP634 100 190023.1 8438003 146.5 84 -60 QSP001 40.5 189616.1 8438077 152.9 70 -60 QSP002 20.5 189632.3 8438081 157.5 0 -90 QSP003 35.4 189620.3 8438048 149.2 0 -90 QSP004 30.5 189647.3 8438010 150.5 74 -60 QSP005 21 189651.1 8438048 157.1 0 -90 QSP006 40 189567.4 8438141 178.1 60 -60 QSP007 26 189632.2 8438129 200 0 -90 QSP009 50 189602.8 8438163 193.5 210 -80 QSP010 36 189608.8 8438153 200 0 -80 RGP001 50 189200 8437834 134.83 92 -55 RGP003 50 189254.2 8437833 144.8 92 -55 RGP004 50 189283 8437832 147.94 92 -55 RGP005 55 189311.2 8437831 149.81 92 -55 RGP006 55 189337.3 8437832 149.42 92 -55 RGP007 50 189362.4 8437831 150.86 92 -55 RGP008 50 189397.1 8437828 155.19 92 -55 RGP009 50 189424.9 8437826 162.04 92 -55 RGP010 60 189452.9 8437829 162.89 92 -55 RGP011 50 189213 8437742 132.67 92 -55 RGP012 61 189232.1 8437731 133.4 92 -55 RGP013 53 189260.8 8437730 136.33 92 -55 RGP014 55 189287.7 8437729 144.8 92 -55 RGP015 50 189317.4 8437729 147.06 90 -55 RGP016 55 189344.5 8437729 141.47 90 -55 RGP017 50 189369.9 8437729 137.05 90 -55 RGP018 49 189399.7 8437728 138.18 92 -55 RGP019 55 189427.6 8437727 146.3 92 -55 RGP020 60 189452.4 8437728 151.54 92 -55 RGP021 50 189618.3 8437880 165.09 92 -55 RGP022 80 189643.4 8437880 173.14 92 -55 RGP023 50 189670.5 8437880 183.23 92 -55 RGP024 50 189688 8437880 188.8 92 -55 RGP025 50 189609.2 8437774 162.83 92 -55 RGP026 50 189631.7 8437774 167.63 92 -55

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 117 HOLE-ID DEPTH EASTING NORTHING ELEVATION AZIMUTH DIP RGP027 50 189654.1 8437776 169.88 92 -55 RGP028 60 189679.1 8437977 170.48 92 -55 RGP029 50 189700.1 8437983 170.97 92 -55 RGP030 50 189731.6 8437982 161.33 92 -55 RGP031 50 189751.7 8437962 162.57 92 -55 RGP032 50 189676.3 8437776 174.41 92 -55 VQ11-001 366 189125.7 8438153 150.52 90 -60 VQ11-002 368 189221.6 8438003 133.24 92.5 -60 VQ11-003 356 189331.8 8438153 149.72 93.53 -60 Source: Tetra Tech, Inc. (August 2020) Figure 10-7: Isometric View of the Quigleys Drilling Pattern

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 118 Source: Tetra Tech, Inc. (August 2020) Figure 10-8: Quigleys Cross-section A-A’ (8,438,200 North +/- 10m window) 10.3 Drilling Procedures The drilling procedures followed by the various companies were reviewed by Vista and were found to meet industry standard practices. The drilling procedures follow these general guidelines. 1) A geologic model is utilized to select a drilling target in both map location and depth. 2) The position of the drill collar is selected and surveyed with the initial azimuth and dip of the drill selected. 3) The method of drilling chosen, i.e., percussion, RC or diamond, determines the type and quality of geologic information that can be recorded. A mix of methods is commonly used. Both percussion and RC produce ground up fragments of rock which tend to obscure detailed geologic description. Diamond drilling is used to obtain intact core samples which retain the geologic structure along with the spatial relationship of where mineralization occurs. Because percussion and RC drilling methods are cheaper than diamond drilling, many of the historical drillholes listed in Table 10-1 use a combination of RC at the top of the hole and diamond drilling as it passes through the mineralized target. 4) The location of the drillhole at depth is monitored by recording changes in azimuth and dip at depth. 5) Rock material obtained is described by a geologist during drilling. Material is collected for further geological description and assay analysis.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 119 6) Core obtained during drilling is described and recorded on site by a geologist. Diamond core is placed in special container for transport for a more detailed geologic description called “logging” along the complete drillhole. The results along with photographs of this logging exercise is entered the drillhole database (see Section 10.4 for more detail). 7) The core is split with one half sent to an outside laboratory to be assayed (see Section 12 for a generalized description of the laboratory protocols) and the remaining core placed in a secured repository. 8) Assay results are entered into the drillhole database. All the remaining material called “pulp” from the laboratory is also placed in a secured repository. The geologic model is then updated with the results of the new drilling. Vista typically utilizes only the diamond drilling method. 10.4 Sampling The sampling method and approach for all drillholes completed after 2012 are as follows: „ The drill core, upon removal from the core barrel, is placed into plastic core boxes. „ The poly core boxes are transported to the sample preparation building. „ The core is marked, geologically logged, geotechnically logged, photographed, and sawn into halves. One-half is placed into sample bags as one-meter sample lengths, and the other half retained for future reference. The only exception to this is when a portion of the remaining core has been flagged for use in the ongoing metallurgical testwork. „ The bagged samples have sample tags placed both inside and on the outside of the sample bags. The individual samples are grouped into “lots” for submission to Northern Analytical Laboratories for preparation and analytical testing. „ All of this work was done under the supervision of a Vista geologist. Please see Section 6 of this Technical Report for information on historical drilling sampling. The QP [Rex Clair Bryan, Ph.D., SME RM] is not aware of any drilling, sampling, or assaying issues that would materially impact the accuracy or the results presented in this Technical Report. The QP has observed the sampling, statistically tested the approach, confirmed quality control procedures employed, and quality assurance actions taken for the Project, and is of the opinion that the data accurately represent the nature and extent of the deposit. 10.5 Summary and Interpretation of Relevant Results The results of drilling at Quigleys and Batman has been used to determine and update the gold resource estimates for the Batman and Quigleys deposits as described in this Technical Report. Vista’s drilling discovered a larger Batman resource by probing deeper with diamond drilling averaging 550 meters in depth. Certain results for Batman are shown in five sectional views in Figure 10-2 through Figure 10-6. While there are random high grade intercepts outside of the core, the majority of higher grade mineralization at Batman resides in the core. Relevant intervals of mineralization at Quigleys are contained within blanket-like zones which are modeled with 3-D wireframes for resource estimation. These zones are shown in Figure 14-14. While there are random high grade intercepts outside of the core, the majority of higher grade mineralization

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 120 resides within the defined zones. See also Section 6.2 for additional information on historic drilling and Section 14 for additional information on the drilling results including geologic modeling of the deposit based on the drilling and additional sectional views of the drillhole data and results. These results may change when there is new drilling, new assays, a new interpretation of geology and economic or mining parameters. For Batman and the existing heap leach material, all of these conditions have remained static since the 2018 Technical Report. The resource estimate for the Quigleys deposit was upgraded to reflect a higher gold price. The following lists the relevant factors that have stayed the same or changed from the 2018 Technical Report: „ There has been no new drilling or assays for all three deposits. The last drilling at the Quigleys deposit was in 2011. „ The latest drilling at both the Batman deposit and the existing heap leach material was in 2017. „ There have been no corrections or additions to the assay data base. „ The geological models, 3D wire frames and surveyed locations of drilling at the Batman and Quigleys deposits are unchanged. „ There has been no change in the geostatistical interpretation of the continuity of mineralization and the assignment of resource classifications. The orientation of the mineralized zones of Batman and Quigleys differ; Batman is steeply dipping, while Quigleys is shallower. „ There has also been no change in the surveyed shape and estimated tonnage of the Tailings Pile. „ There has been no change in the assumed mining method, costs or metallurgical parameters that are used to classify estimates for all three deposits. „ The assumed price of gold has been updated for the Quigleys deposit from $1,200 to $1,300 per ounce. This change has altered the potential mineable material within a Whittle(TM) pit.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 121 11.0 SAMPLE PREPARATION, ANALYSES AND SECURITY The following section describes the sample preparation, analyses and security undertaken by Vista. 11.1 Sample Preparation The diamond drilling program was conducted under the supervision of the geologic staff composed of a chief geologist, several experienced geologists, and a core handling/cutting crew. The core handling crew was labor recruited locally. Facilities for the core processing included an enclosed logging shed and a covered cutting and storage area that was fenced in. Both of these facilities were considered to be limited access areas and kept secured when work was not in progress. The diamond drill core was boxed and stacked at the rig by the drill crews. Core was then picked up daily by members of the core cutting crew and transported directly into the logging shed. Processing of the core included photographing, geotechnical and geologic logging, and marking the core for sampling. The nominal sample interval was one meter. When this process was completed, the core was moved into the core cutting/storage area where it was laid out for sampling. The core was laid out using the following procedures: „ One meter depth intervals were marked out on the core by a member of the geologic staff; „ Core orientation (bottom of core) was marked with a solid line when at least three orientation marks aligned and used for structural measurements. When orientation marks were insufficient an estimation orientation was indicated by a dashed line; „ Geologic logging was then done by a member of the geologic staff. Assay intervals were selected at that time and a cut line marked on the core. The standard sample interval was one-m, with a minimum of 0.4 m and a maximum of 1.4 m; „ Blind sample numbers were then assigned based on pre-labeled sample bags. Sample intervals were then indicated in the core tray at the appropriate locations; „ Each core tray was photographed and restacked on pallets pending sample cutting and stored on site indefinitely; and „ 9,635 assays were added for the October 2012 resource update, an additional 7,601 assay intervals were added for the March 2013 resource, and 729 assay intervals were added for the 2017 model update. The core was then cut using diamond saws with each interval placed in sample bags. At this time, the standards and blanks were also placed in plastic bags for inclusion in the shipment. A reference standard or a blank was inserted at a minimum ratio of 1 in 10 and at suspected high grade intervals additional blanks sample were added. Standard reference material was sourced from Ore Research & Exploration Pty Ltd and provided in 60 g sealed packets. When a sequence of five samples was completed, they were placed in a shipping bag and closed with a zip tie. All of these samples were kept in the secure area until crated for shipping. Samples were placed in crates for shipping with 100 samples per crate (20 shipping bags). The crates were stacked outside the core shed until picked up for transport.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 122 11.2 Sample Analyses The following analytical and testing laboratories used by Vista for lab preparation, analyses, and check assays are listed in (Table 11-1). The laboratories are separate commercial entities from Vista. Each laboratory meets all the required standards established by their industry associations and regulatory agencies. With the exception of Genalysis, all have presented their certification of being an accredited laboratory meeting all the international standards for testing and calibration. Table 11-1: Assay and Preparation Laboratories Laboratory Address Purpose Abbreviation Certifications ALS | Minerals 31 Denninup Way Malaga, WA 6090 Main assay analyses ALS ISO:9001:2008 and ISO 17025 Certified ALS | Minerals 13 Price St Alice Springs, NT 0870 Sample Preparation ALS Alice Springs ISO 9001:2008 and ISO 17025 Certified Genalysis Laboratory Services (Intertek Group) 15 Davison St Maddington, WA 6109 Check Analyses Genalysis Unable to verify North Australian Laboratories Pty Ltd MLN 792 Eleanor Rd Pine Creek, NT 0847 Alternative assay analyses NAL ISO 10725 Certified NT Environmental Laboratories (Intertek Group) 3407 Export Dr Berrimah, NT 0828 Check Analyses NTEL ISO 17025 Vista is completely independent of any analytical testing entity presented in this Technical Report. The QP [Rex Clair Bryan, Ph.D., SME RM] has determined that there is no apparent conflict of interest between Vista and its analytical laboratories. Each of the Laboratories listed follow their own quality controls based on international standards. For example, ALS uses accredited methods specified by ISO/IEC 17025 in North America and Australia. The standards specify a recipe and set of quality control steps that the laboratory should follow: 1) How the sample should be coded to obscure its relationship to the drilling geometry. 2) How the received sample should be prepared. 3) What analytical steps be taken. 4) Given the required detection level and material analyzed and instruments should be employed. 5) What internal quality controls should be done such as: periodic assaying of duplicate samples, the insertion of certified calibration samples; utilizing blanks; and including a required number of randomized samples Vista as a gold project requires assays to be done with the industry standard of fire assay. To get these fire assay results a generalized discussion of the steps are: 1) Core samples from drillholes are split at Mt Todd into two with one archived and the other sent to analytical laboratory. A more detailed discussion of how samples are prepared at Mt Todd is in Section 11.1. 2) At the lab the sample is pulverized into a powder, with a subsample taken for fire assay.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 123 3) This subsample is then mixed with a fluxing agent. The remaining pulverized material is called a pulp archive, which can be used for within and between laboratory validations. 4) The chosen sample is then heated in a furnace where it fuses and separates into a “button” which contains the gold. There are several methods to extract the gold from the button. 5) The most common method is by combining the button with lead as a collector. The lead oxidizes and is absorbed into a cupel leaving a gold bead. 6) Due to the relatively low concentration of gold at Mt Todd the lab must choose an analytical method able to detect a least 5ppb gold. The methods are generally by atomic absorption (AA) or inductively coupled plasma-mass spectrometry (ICP-MS). 7) The bead is dissolved in aqua regia or dissolved in hydrochloric acid and then analyzed by the selected instrument. 8) The resultant assay values are reported by an assay certificate which is electronically or physically sent to the staff at Mt Todd. The assay results are entered with the drilling database. The QP [Rex Clair Bryan, Ph.D., SME RM] has reviewed results of the quality control procedures employed by Vista and has determined that they meet industry standards. For example, a comprehensive check of the quality of 12,365 assays in the database was undertaken by an outside auditor (Mine Development Associates, 2011). Records were selected from among those that relate to mineralization that is still in situ. These were divided into three subsets, to be checked by three individual checkers. An additional 1,812 records were spot-checked in greater detail by a fourth individual. After the checking was done, from the original 12,365 records, 95% were selected that had gold value in the database and a gold assay in a source documents such as an assay certificate. Of the assay pairs, 8,549 were “historic” in the sense of dating prior to Vista’s acquisition of the project and 3,262 assay pairs originate with Vista’s work. For context, Mt Todd assay table as of August of 2011 contained 118,550 records, 26,579 of them originating from Vista’s work. Eight significant outliers were found with gold values in the database that differed from the source documents. Those eight were double-checked and were found to be real cases of the database containing data that differ from the source documents. Table 11-2 shows that most of the differences between the gold values in the database and those gleaned from the source documents are very small, although around economic cutoff grades the differences may well represent large percentages. More than 99% of the differences fall in the range -0.1 ppm Au to +0.1 ppm Au which is below the 0.4 ppm cutoff grade. However, a Mann-Whitney Test suggests that the differences between the two populations are not statistically different. Table 11-2: Comparison of Assay Values between the Database and Source Documents (MDA, 2011) Center of Cell Range in ppm Au (+/- 0.1 ppm Au) Frequency Percent Cumulative Percent -1.2 0 0.00 0.00 -1 0 0.00 0.00 -0.8 1 0.01 0.01 -0.6 0 0.00 0.01 -0.4 0 0.00 0.01 -0.2 3 0.04 0.05

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 124 Center of Cell Range in ppm Au (+/- 0.1 ppm Au) Frequency Percent Cumulative Percent 0 8,539 99.88 99.93 0.2 5 0.06 0.99 0.4 0 0.00 99.99 0.6 0 0.00 99.99 0.8 0 0.00 99.99 1 0 0.00 99.99 1.2 1 0.01 100.00 Differences with no rounding or truncation of data (Diff_Cet Table 11-3 and Table 11-4 show the comparison of the gold grade assays within the database and source documents. One of the three data sets checked contained 3,262 assays from drilling campaigns by Vista in 2007 and 2008. Checks of the Vista data against original sources were done by one individual, using essentially the same procedures as had been used for checking the historic assays. A summary table of the findings is presented, as Table 11-3. Of the 12 differences noted in Table 11-3, two are significant. „ A gold value of 0.005 ppm Au in the database compared to the correct gold value of 0.8 ppm Au. „ A gold value of 1.08 ppm Au in the database compared to the correct gold value of 0.01 ppm Au. In addition, a separate detailed audit was done on 638 assays on Vista drillhole VB08-036. This audit shows that discrepancies within the database on the global resource estimate are not material. Based on his review, the QP has determined that the historical and Vista assays in the Mt Todd database are useable for resource modeling. Table 11-3: Summary of Comparisons of Historical Assays (MDA, 2011) Historical Assays Au in PPM Differences, Source - Database in PPM Database Source Average 0.79 0.70 0 Std Dev 1.48 1.48 0.01 Count 1171 1171 565 Max 33.44 33.45 0.255 Min 0.005 0.005 -0.29 Median 0.3 0.3 0 Differences > 0.01 ppm Au 20 Differences < 0.01 ppm Au 4

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 125 Table 11-4: Summary of Comparisons of Vista Assays (MDA, 2011) Vista Assays Au in PPM Differences, Source - Database in PPM Database Source Average 0.79 0.78 0 Std Dev 1.89 1.89 0.02 Count 3262 3262 12 Max 55.37 55.37 0.79 Min 0.005 0.005 -1.07 Median 0.26 0.26 0 Differences > 0.01 ppm Au 3 Differences < 0.01 ppm Au 6 The QP [Rex Clair Bryan, Ph.D., SME RM] has reviewed and accepted the quality assurance protocols are employed by Vista for its drilling, sample preparation and assays. Vista requires periodic rechecking of assays both within and between laboratories. As an example, prior to the 2011 drilling campaign, the majority of samples were transported first to ALS in Alice Springs (NT) for sample preparation. After preparation, samples were then forwarded on to ALS in Malaga (WA) for assay analyses. One in every 20 pulp or reject was sent from ALS in Alice Springs to Northern Australian Laboratories (NAL), Vista was notified by email which samples were sent to NAL. For the 2011-2012 drilling campaign samples for assay were sent to NAL lab in Pine Creek, NT. Figure 11-1 shows the results of check assays on one in every 20 pulps or rejects that were completed by NT Environmental Laboratories. No bias in assays was found with a slope of 0.992 and a correlation of 99%. There was only one significant difference that was detected from a total of 2,948 comparisons. Figure 11-2 shows a comparison of original 78 pulp assays between the NAL and ALS laboratories. The assay values showed no bias with a slope of 0.99 and a correlation of 99%. Following completion of assay results, all pulps and reject material was shipped back to the Project site and stored.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 126 Figure 11-1: NAL Pulp Repeats

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 127 Figure 11-2: Original Pulp Cross Lab Checks

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 128 11.3 Sample Security NAL is the primary laboratory for the current drilling program. The NAL laboratory is located in the town of Pine Creek, approximately 100 km distant by road. Samples were picked up and transported by NAL employees. Sample shipments were scheduled for approximately once a week. The crates were picked up on site by NAL for direct road transport to the assay lab. A sample transmittal form was prepared and included with each shipment and a copy was filed in the geologist office on site. When the shipment left site, sample transmittals were prepared and e-mailed to NAL. When the shipment arrived at the preparation facility the samples were lined out and a confirmation of sample receipt was e-mailed back to Vista. The QP [Rex Clair Bryan, Ph.D., SME RM] is satisfied with the adequacy of sample preparation and analytical procedures employed by Vista given the fact that Vista has completed more than 50,000 m of core drilling in the Batman deposit, to verify the approximately 98,000 m of historic drilling. The QP is also satisfied that sample security measures meet industry standards. Statistical analysis of the various drilling populations and quality assurance/quality control (QA/QC) samples has not either identified or highlighted any reasons to not accept the data as representative of the tenor and grade of the mineralization estimated at the Batman deposit.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 129 12.0 DATA VERIFICATION 12.1 Drill Core and Geologic Logs Multiple site visits were performed by the QP [Rex Clair Bryan, Ph.D., SME RM] for the resource estimation portion of this Technical Report. During that visit, the QP found a comprehensive drillhole database comprised of drill core, photographs of the drill core, assay certificates and results, and geologic logs. All data were readily available for inspection and verification. In addition, most of the subsequent companies or their consultants that have examined the project have completed checks of the data and assay results. The author reviewed drill core, drill core logs and assay certificates and found a minimal number of errors (i.e., mislabeled intervals, number transpositions), which were corrected in development of the resource estimation. It is the opinion of the QP responsible for this section that the databases and associated data were of a high quality in nature and valid for use in mineral resource and reserve estimation. The QP responsible for this section found no significant discrepancies with the existing drillhole geologic logs and is satisfied that the geologic logging, as provided for the development of the three-dimensional geologic models, fairly represents both the geologic and mineralogic conditions of each of the deposits that comprise the Project. 12.2 Topography The topographic map of the project area was delivered electronically in an AutoCAD® compatible format and represents the topography in half-meter accuracy. The native coordinate system of the topography is GDA94 / Map Grid of Australia (MGA) zone 53, and for this resource update and as the Project goes forward GDA94 / MGA zone 53 will be the used coordinate system. The surveyed drillhole collar coordinates, once translated to GDA94 / MGA zone 53 agree well with the topographic map; it is the opinion of the QP responsible for this section that the current topographic map is accurate and accurately represents the topography of the project area. In addition, it is suitable for the development of the geologic models, mineral resource estimates, and mineral reserve estimates. 12.3 Verification of Analytical Data As part of the 2007 exploration program, an exercise to verify the historic assay results and establish procedures for subsequent analytical work was completed. This program consisted of two components; re- assaying of a portion of the historic drillholes, and assaying of the new core drillholes. A multi-phase program evaluated the accuracy of gold assays generated by NAL on Mt Todd core samples. The test involved three phases including, 1) cross checking assay standards used in the program between NAL and ALS-Chemex, 2) preparing and assaying 30, one-m intervals of remaining half-core and detailed analysis of crushing and analytical performance between the two labs, and 3) screen sieve assay analysis of 45 coarse reject samples plus the 45 comparable remaining half core samples. Analysis of the results from the two labs confirmed that finer material tends to be higher grade and that this fine material had been preferentially lost through the coarse-weave sample bags during storage and handling of the coarse reject samples. Vista now uses commercial polyester sample bags and loss of fines is no longer an issue. The test also showed good reproducibility between labs in all tests at grade ranges typical of the

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 130 deposit. Greater variance, which is not unexpected, showed up in the few samples assaying in the 5-20 g-Au/t range. Figure 12-1 details the results of the analytical check program that was completed on the 2007 exploration drillholes. The program was designed to check both internal laboratory accuracy and inter-laboratory accuracy. NAL was the primary laboratory for completion of the sample analyses. ALS-Chemex in Sydney, Australia performed the inter-laboratory analyses. As can be seen from the plot, the correlation coefficient was 0.997 for the re-splits of original assays.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 131 Figure 12-1: NAL Resplit Analyses

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 132 12.3.1 Latest Drilling Data Verification For the March 2018 resource estimate, a detailed data verification procedure was undertaken by the QP [Rex Clair Bryan, Ph.D., SME RM] which focused on two drilling campaigns (VB12-015 through VB17-003 inclusive). This verification was accomplished by: reviewing the assay database received from Vista, comparing results with laboratory certificates received directly from the laboratory and reviewing results of the field QA/QC samples. In April 2018, the QP verified that the latest four metallurgical drillholes (VB17-004, VB18-001, -002, and -003) followed Vista’s drilling and sampling protocols. For the 13 drillholes from the 2012 exploration program, there were 7,601 intervals assayed. For the nine drillholes from the combined 2015-2017 exploration programs, there were 1,770 intervals. In addition to Au and other precious metals, most intervals had multi-element and environmental test results as well. Similar to previous work, the assay interval averaged one meter with a minimum interval of 0.4 m and a maximum interval of 1.4 m. No errors were noted in the assay data received other than selenium results for one drillhole that were erroneously entered. This was corrected by Vista. A spot-check of approximately 14% of the received database with laboratory certificates requested and received from NAL showed a 100% correct correlation of reported values. Field QA/QC samples (those submitted with the drillhole samples to the laboratory) were also analyzed. Five standards (standard reference materials [SRMs]) were used by Vista with ranges of Au between 0.334 and 5.49 ppm of variable mineral/rock composition. Results of the SRMs were plotted as the relative difference to the average SRM certified Au concentration and are shown in Figure 12-2. Of the 385 results, no drift was noted over time and all but four were within 10% of the certified value. Of the four that fell outside that range the highest offset was 13.8%. One value was clearly a mislabeled sample and when plotted with the assumed correct standard fell within the 10% range. Figure 12-2 demonstrates the variance is greatest at lower Au concentrations and this is normally seen with most Au analytical data. Field blanks were also reviewed and found to be acceptable. Of 388 blank results, six blanks had Au concentrations greater than detection limit of 0.01. The maximum value was 0.11 ppm. Again, no drift was noted in the data over time. Because the current drilling campaign uses core, a regular program of field duplicates is not instituted at this time, but approximately 30% of samples have at least one replicate assay performed and an additional 3% of these have a second replicate assay. Replicates are taken from pulp when the primary sample is taken and run in the same analytical “batch.” Variability is highest at concentrations near detection limit, but overall trends are very good for the drillholes. Figure 12-3 shows the first replicate value against the primary value by drillhole. Equally good correlation is seen for the second replicates against the original and against the first replicate value. The QP is of the opinion that the current field QA/QC program and results meet industry standards and that the assay database adequately reflects values reported from the laboratory and is suitable for use in mineral resource and mineral reserve estimation.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 133 Source: Tetra Tech, Inc (August 2017) Figure 12-2: Scatterplot of Relative Au Value to Certified Standard Reference Material Value

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 134 Source: Tetra Tech, Inc (August 2017) Figure 12-3: Scatterplots (Log Scale) of Replicates by Drillhole

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 135 Figure 12-4 shows the location of a metallurgical drilling campaign that produced three cross sections containing new holes that almost twin previous ones. Figure 12-5 shows one of the twined sections. It is important to note that the twinned holes target the higher grade ore of the Batman deposit. It is the opinion of the QP that this serendipitous twinning exercise helps confirms that the geologic modeling, drilling position, assay sampling and block modeling meet industry standards. Source: Tetra Tech, Inc.(August 2020) Figure 12-4: Location of Metallurgical Drillholes

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 136 Source: Tetra Tech, Inc. Figure 12-5: Two Views of VB07-013, VB18-002 and VB08-036 in Cross-sections

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 137 13.0 MINERAL PROCESSING AND METALLURGICAL TESTING This section reports on the work done to develop the understanding of the metallurgical characteristics of the remaining ore in the Batman deposit. This understanding contributes to the design of a technically effective and economically efficient gold recovery operation. 13.1 Summary Key conclusions drawn from the metallurgy studies to date are: „ Mt Todd (and in particular the Batman deposit) ore is among the hardest and most competent ore types processed for mineral recovery. The most energy efficient comminution circuit has been determined to be the sequence of primary crushing, closed circuit secondary crushing, and closed circuit HPGR tertiary crushing and ore sorting, followed by two stages of grinding. „ The ore is free-milling, is not preg-robbing, and is amenable to gold extraction by conventional cyanidation processes. „ The ore has moderate to high cyanide consumption, determined to be 0.876 kg of sodium cyanide per tonne of ore. This is largely due to the presence of sulfides, cyanide-consuming copper, and not recycling cyanide from leach residue prior to cyanide destruction. „ The ore requires a P80 grind of 40 μm and 30-hour leach residence time to achieve a nominal 91.9% gold recovery net of solution loss from ore with a pit head grade of 0.84 g-Au/t. 13.2 Historic Metallurgical Test Programs The Mt Todd deposit is a large low-grade gold deposit. The average grade of the gold mineralization is approximately 1 g-Au/t. The gold mineralization occurs in a hard, uniform greywacke host and is associated with sulfide and silica mineralization which has resulted from deposition along planes of weakness that had opened in the host rock. Gold is fine grained (<30 μm) and occurs with both silica and sulfides. The host rock is very competent with a Bond Ball Mill Work Index (BWi) of 23 to 30 kWh/t. A substantial body of knowledge has been accumulated for the metallurgy of the Mt Todd ore, some from the historical operation of the mine, but more importantly, detailed information has been developed from recent sampling of the remaining ore body. Observations are as follows: „ 1988-1997 metallurgical studies by previous owners (Pegasus) led to the design and construction of a treatment plant comprised of crushing, milling to a P80 of 150 μm, sulfide flotation, concentrate regrind and cyanidation, and, separate CIL cyanidation of flotation tailings. Operational efficiencies were lower than planned due to ore hardness, presence of cyanide- soluble copper minerals, and inefficient flotation performance resulting from the presence of free cyanide in the process water (from recycled tailings decant water). One could reasonably state that these operational challenges were the result of inadequate design and equipment selection, in part due to an incomplete understanding of the deposit. These process difficulties together with the collapse of the gold price led to the cessation of operations in November of 1997. „ In 2006, Vista acquired the Project with the belief that each of these challenges could be overcome through the use of current technology, adequate metallurgical testing and higher gold prices. Vista’s consultant, Resource Development Inc. (RDi), completed a study using

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 138 historical metallurgical data and test results from transition ore samples. RDi proposed a flowsheet consisting of crushing and grinding followed by rougher flotation to produce a sulfide concentrate containing 85% of the gold. Rougher tailings, substantially barren of gold and sulfides, would be discarded to a benign tailings dam. Rougher concentrate would be reground to enable upgrading in a cleaner flotation circuit to produce a saleable copper concentrate containing 50% of the gold. Cleaner tailings would be cyanide leached in a CIL circuit for gold recovery. The cleaner tailings would be subjected to cyanide destruction and stored in a separate sulfide tailings dam. „ The design incorporated energy efficient HPGR technology in the comminution circuit to handle the hard ore. These processing advantages combined with a higher gold price significantly improved the viability of the proposed operation. It then became necessary to confirm if the remaining ore had the same metallurgical characteristics as the historically processed ore. In 2007/2008 two exploration drilling programs were completed focusing on the deeper ore beneath the existing Batman pit. The following composites/samples were prepared for RDi’s testwork conducted on the samples of the deeper Batman ore from the 2007/2008 drilling program: „ Composite 1 – 1,200 kg composite sample made up from 2007 drill core. The composite consisted of samples from five drillholes selected to be representative of a cross section of the deposit. The head assay was 1.3 g-Au/t, 0.92% S and 447 ppm Cu. The sequential copper analysis indicated 80.4% of the copper in the sample was primary copper. The dominant sulfide in the sample was pyrrhotite. „ Composite 2 – 140 kg composite sample made up from 2008 drill core. The head assay was 0.89 g-Au/t and 450 ppm Cu. The sequential copper analysis indicated 80.3% of the copper in the sample was primary copper. The dominant sulfide in the sample was pyrrhotite. „ Drillhole 41 sample was sourced from the oxide and transitional zones (depth of 0–65 m). The head assay was 1.78 g-Au/t, 1.42% S, 448 ppm Cu. „ The new cores were more representative of the remaining resource and samples were selected for confirmatory metallurgical test work. It was confirmed that the ore was extremely hard but it was not possible to repeat the flotation results previously achieved. The tests indicated that gold recovery into the rougher flotation concentrate was ± 80% at a grind P80 of 74μm but copper could not be upgraded to saleable concentrate grade of ± 20% Cu. The best results were ± 6% Cu using the same test procedure as employed for earlier core testing (2006). „ Investigations revealed that the historical core tested in 2006 was transition zone material containing copper minerals predominantly as secondary copper which is known to be a major consumer of cyanide. The major sulfide mineral was pyrite. However, the 2007 and 2008 drill core had primary copper as predominant copper species and pyrrhotite as the major sulfide mineral. Pyrrhotite is known to float more readily as compared to pyrite and is significantly more difficult to depress in the flotation process. It was difficult to selectively float copper minerals and produce a copper concentrate without the dilutive effect of pyrrhotite and other gangue minerals. Consequently flotation was dropped from the flow sheet and replaced with whole ore leach.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 139 In 2010/2011 a confirmatory drilling campaign and metallurgical test program was conducted on the remaining Batman resource. The objective was to validate the findings of the 2007/2008 programs and to expand the level of understanding of variability of metallurgical performance within the Batman ore body. Samples used for the 2011 metallurgical testwork program were sourced from eight drillholes drilled 2010/2011. The drillholes were orientated to intersect the main Batman ore body beneath the existing pit and are representative of the ore within the Technical Report pit shell. All samples from drillholes labeled VB11 were drilled in 2011, logged, packaged then shipped directly to the laboratory for processing. Drillholes labeled MHT were drilled and logged during 2010 and were stored in cold storage before being transported to the laboratory in 2011. „ The test program was designed by Vista, supervised by Ausenco Limited (Ausenco), and executed by ALS Ammtec in Perth, Western Australia. There were a total of ninety-nine composited gold ore drill core intervals originating from the Project area. The metallurgical testwork included head analyses, crushing tests (HPGR and conventional crush), comminution testing, mineralogical analyses, leaching tests, cyanide detoxification and thickening and rheology testing. The test results confirmed that gold recovery by whole ore leach was the appropriate approach to process design. „ Vista had additional testwork undertaken in 2016 at RDi on the 2011 drilling samples. The test results indicate that the recovery was independent of the ore types but was somewhat dependent on the content of quartz in the ore. Also testing of the HPGR product indicated that the plus 5/8-in material had the potential to be treated by ore sorting to reject non- sulfide material. Since this was undertaken in small-scale tests, it provided incentive to undertake large scale tests to improve the process flowsheet and economics of gold production. 13.3 2017 Metallurgical Testwork During January and February 2017 Vista completed drilling and logging of approximately 1,700 m of PQ (3.75 in diameter) core to obtain four 5-tonne bulk samples of ore representing different parts of the deposit. These composites were selected to represent both near-term and longer-term mining and are spatially located to provide variability both horizontally and vertically. The primary objective of this phase of the test program was to perform sufficient metallurgical testwork to confirm the preferred process flowsheet developed during the last two years and associated reagent consumptions. 13.3.1 HPGR Testing at Thyssen-Krupp Industries (TKI) The four composite samples were sent to TKI (formerly Polysius) in Germany for the HPGR crushing component of the test program. The material was crushed in a one meter diameter HPGR unit. The material was subjected to a single pass through the HPGR and then screened on 16mm (5/8 inch) and each composite had the coarse fraction weighed and placed into a drum. The fine fraction was weighed and placed into several drums. The coarse fractions were sent to Tomra Sorting Solutions/Outotec for ore sorting. The test protocol is given in Figure 13-1. The weights of the plus and minus 16mm fractions for each composite are given in Table 13-1.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 140 Source: Resource Development Inc, September 2019 Figure 13-1: Protocol for HPGR/Ore Sorting Table 13-1: Material Balance for HPGR Tests Composit e No. Sample Weight, Kgs HPGR Products % +16 mm -16 mm 1. 4399.9 17.5 82.5 2. 4977.7 17.8 82.2 3. 4370.7 16.6 83.4 4. 4317.3 18.7 81.3

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 141 13.3.2 Tomra/Outotec Ore Sorting Testwork Each plus 16mm sample was weighed at the Tomra sorting facility. Each composite was split into three parts. Each split sample was subjected to a two-step automated sorting test designed to separate the gold-bearing sulfide minerals and quartz veining from non-gold bearing waste material. The first step (XRT) sorts the material by measuring differences in density to target the gold-bearing sulfide material. Three different sensitivities (1%, 2% and 5%) were tested. The X-ray Transmission (XRT) material was then washed to remove the fines which could interfere with the laser ore sorting. The second step (laser) separates the gold-bearing, quartz-veining material. The test results, summarized in Table 13-2, indicate the following: „ Open-circuit HPGR produced approximately 18% of the feed as a plus 16mm fraction. „ The ore sorting rejected approximately 10% of the run-of-mine feed as below cut-off grade material. Approximately 1.3% of the gold was rejected with the waste fraction. „ Removal of waste resulted in approximately 8% improvement in estimated mill feed grade (average life-of-mine grade of 0.91 g/t Au compared to 0.84 g/t Au reserve grade).

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 142 Table 13-2: Tomra Sorting Test Results Test Product (XRT + Laser + Wash) Final Reject Head Grade of +16mm To Sorting Wt Au (g/mt) Ag (g/mt) Sulfur (%) CN Soluble Cu (ppm) Wt Au (g/mt) Ag (g/mt) Sulfur (%) CN Soluble Cu (ppm) Wt Au (g/mt) Ag (g/mt) Sulfur (%) CN Soluble Cu (ppm) Composite # 1 XRT Sensitivity at 5% 1.1 190.2 0.817 0.7 1.09 45.6 125.5 0.103 0.2 0.24 10.0 315.7 0.533 0.6 0.89 30.65 Distribution 60.2% 92.3% 83.7% 87.3% 87.0% 39.8% 7.7% 16.3% 12.7% 13.0% 100.0% 100.0% 100.0% 100.0% 100.0% XRT Sensitivity at 2% 2.1 101.5 0.541 1.0 1.12 38.9 118 0.110 0.4 0.23 11.2 219.53 0.309 0.9 0.83 23.21 Distribution 46.2% 80.9% 68.8% 80.8% 74.1% 53.8% 19.1% 31.2% 19.2% 25.9% 100.0% 100.0% 100.0% 100.0% 100.0% XRT Sensitivity at 1% 3.1 71.4 0.758 2.2 0.94 42.4 124.5 0.086 0.2 0.27 12.5 195.9 0.331 1.7 0.80 22.94 Distribution 36.4% 83.5% 86.0% 66.7% 65.4% 63.6% 16.5% 14.0% 33.3% 34.6% 100.0% 100.0% 100.0% 100.0% 100.0% Composite # 2 XRT Sensitivity at 5% 4.1 193.2 0.365 2.1 0.73 27.8 117.5 0.075 0.2 0.23 6.5 310.7 0.255 1.5 0.55 19.25 Distribution 62.2% 88.9% 94.6% 83.9% 87.2% 37.8% 11.1% 5.4% 16.1% 12.8% 100.0% 100.0% 100.0% 100.0% 100.0% XRT Sensitivity at 2% 5.1 138.4 0.449 11.8 1.03 40.7 114.5 0.106 0.2 0.18 8.1 252.86 0.294 10.1 0.90 25.26 Distribution 54.7% 83.6% 98.6% 87.3% 85.5% 45.3% 16.4% 1.4% 12.7% 14.5% 100.0% 100.0% 100.0% 100.0% 100.0% XRT Sensitivity at 1% 6.1 132.9 0.566 35.7 0.86 32.4 151.5 0.185 0.2 0.22 10.7 284.4 0.363 23.6 0.45 20.23 Distribution 46.7% 72.9% 99.4% 77.4% 71.9% 53.3% 27.1% 0.6% 22.6% 28.1% 100.0% 100.0% 100.0% 100.0% 100.0% Composite # 3 XRT Sensitivity at 5% 7.1 110.3 0.255 1.0 0.51 64.1 94 0.072 0.4 0.12 23.2 204.3 0.171 0.9 0.41 43.12 Distribution 54.0% 80.6% 75.0% 83.4% 75.2% 46.0% 19.4% 25.0% 16.6% 24.8% 100.0% 100.0% 100.0% 100.0% 100.0% XRT Sensitivity at 2% 8.1 106.4 0.570 3.6 0.64 94.7 139.5 0.233 0.4 0.13 36.7 245.87 0.379 2.7 0.62 59.23 Distribution 43.3% 65.1% 87.2% 78.9% 64.8% 56.7% 34.9% 12.8% 21.1% 35.2% 100.0% 100.0% 100.0% 100.0% 100.0% XRT Sensitivity at 1% 9.1 86.2 0.282 13.5 0.58 96.7 153.5 0.055 0.2 0.11 33.6 239.7 0.136 10.6 0.69 54.55 Distribution 36.0% 74.2% 97.4% 74.8% 60.5% 64.0% 25.8% 2.6% 25.2% 39.5% 100.0% 100.0% 100.0% 100.0% 100.0%

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 143 Test Product (XRT + Laser + Wash) Final Reject Head Grade of +16mm To Sorting Wt Au (g/mt) Ag (g/mt) Sulfur (%) CN Soluble Cu (ppm) Wt Au (g/mt) Ag (g/mt) Sulfur (%) CN Soluble Cu (ppm) Wt Au (g/mt) Ag (g/mt) Sulfur (%) CN Soluble Cu (ppm) Composite # 4 XRT Sensitivity at 5% 10.1 148.0 0.901 1.4 0.99 43.0 98 0.192 0.4 0.23 18.9 246.0 0.619 1.3 0.88 32.67 Distribution 60.2% 87.6% 83.8% 86.7% 77.0% 39.8% 12.4% 16.2% 13.3% 23.0% 100.0% 100.0% 100.0% 100.0% 100.0% XRT Sensitivity at 2% 11.1 127.2 0.933 2.3 1.32 46.4 136 0.127 0.4 0.21 13.8 263.17 0.516 2.1 1.18 28.88 Distribution 48.3% 87.3% 84.3% 85.5% 75.2% 51.7% 12.7% 15.7% 14.5% 24.8% 100.0% 100.0% 100.0% 100.0% 100.0% XRT Sensitivity at 1% 12.1 112.9 1.005 17.0 1.67 44.3 161.5 0.113 0.4 0.26 9.9 274.4 0.480 15.3 1.70 23.61 Distribution 41.1% 86.1% 96.7% 81.8% 75.3% 58.9% 13.9% 3.3% 18.2% 24.7% 100.0% 100.0% 100.0% 100.0% 100.0%

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 144 13.3.3 Preparation of Composites for Metallurgical Testwork The HPGR product (minus 16mm) and the ore sorting products were weighed for each composite. This was followed by blending of the minus 16mm product and splitting using a cone and quarter process to obtain quarter portions of the material for each composite. The ore sorting product was proportioned into the split samples to prepare the composite samples, representing the product of crushing with sorting as feed to leach processing. The composite samples were stage crushed to nominal 6 mesh. However, the required samples were split out at 3/4 inch material for abrasion testing. The minus 6 mesh material was thoroughly blended and split into 1 kg and 10 kg charges, and approximately half the material was stored in drums. 13.3.4 Mineralogical Study The four prepared composite samples were submitted for mineralogical study with emphasis on gold, silver, and speciation of pyrrhotite. Each sample was prepared as a standard polished thin section for study by transmitted/reflected light microscopy. The highlights of the study indicate the following: „ The mineralogy of the four composites was very similar. „ Quartz was the primary phase in all samples and accounts for over 60% of the volume. „ Quartz occurs as very fine mosaic grains (5 to 10 μm) or as angular to rounded grains in sizes from 5 to 125 μm. Some very course fragments of quartz up to several millimeters were also present in all samples. „ The coarse quartz was commonly associated with coarse grain sulfides. „ Other silicate minerals identified in the samples were biotite, muscovite, chlorite and plagioclase feldspar. „ Sulfide minerals represented 2% to 3% in each composite. Pyrite was common in all samples and occurred as euhedral cubes and anhydral grains (3 to 300 μm). „ Pyrite concentration was highest in Composites 1 and 2. It was intermixed with marcasite and arsenopyrite. „ Arsenopyrite was most prominent in Composite 3 with a grain size of up to 100 μm. „ Other sulfide minerals present included chalcopyrite, sphalerite and galena. „ Pyrrhotite was identified in all four composites. It was determined to have monoclinic structure. „ Most of the gold grains identified were associated with pyrite and ranged in sizes from 3 to 28 μm. „ No discrete silver minerals were identified in any of the composite samples.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 145 13.3.5 Head Analyses The composite samples were submitted for head analysis. The test results are summarized in Table 13-3, Table 13-4, and Table 13-5. The results indicate the following: „ The samples assayed from 0.348 g/t Au to 0.760 g/t Au. „ The total sulfur content ranged from 0.43% to 1.26%. „ The copper valves ranged from 241 ppm to 467 ppm. „ The samples contained significantly lower gold values than projected from the drilling data as shown in Table 13-5. Table 13-3: Head Analyses of Composite Samples Element Composite 1 2 3 4 Au, g/t 0.679 0.350 0.350 0.699 Assay 1 Assay 2 0.672 0.346 - 0.713 Average 0.675 0.348 0.350 0.706 Ag, g/t 1.6 3.7 1.2 0.8 STotal, % 1.26 0.67 0.43 0.76 Table 13-4: Whole Rock Analyses of Composite Samples Element Percent Composite 1 2 3 4 Al 7.33 7.65 7.44 6.97 Ca 0.33 0.32 0.17 0.37 Fe 5.48 5.02 5.44 4.97 K 3.59 3.63 3.03 3.06 Mg 1.14 1.23 1.26 1.16 Na 0.29 0.36 0.50 0.36 Ti 0.19 0.21 0.20 0.22 ppm As 50 103 403 113 Ba 579 622 574 548 Bi <10 <10 <10 <10 Cd 8 9 7 7 Co 21 22 22 18 Cr 83 97 111 88 Cu 467 285 241 384

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 146 Element Percent Composite 1 2 3 4 Mn 352 372 360 368 Mo <175 <1 <1 <1 Ni 213 72 78 74 Pb 17 81 302 222 Sr 83 23 17 20 V <10 86 100 92 W 575 11 <10 <10 Zn 240 392 421 Table 13-5: Assayed vs. Projected Head Analyses g/t Au Assayed Projected Composite 1 0.675 1.54 Composite 2 0.348 0.99 Composite 3 0.350 0.74 Composite 4 0.706 0.56 13.3.6 Abrasion Indices The samples were submitted for Bond abrasion index determination. The test results are summarized in Table 13-6. The test results indicate that the material is low to moderately abrasive. Table 13-6: Abrasion Indices for the Various Composite Samples Sample Ai, g Composite CC ¾ X ½ in 0.1603 Composite 1 – 16mm 0.2278 Composite 2 – 16mm 0.1616 Composite 3 – 16mm 0.2006 Composite 4 – 16mm 0.2250

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 147 13.3.7 Bond Ball Mill Work Indices Bond ball mill work indices (BWi) were determined at a grind size of P80 of 100 mesh for the various products, namely HPGR, ore-sorting, composite samples and waste material. The results are summarized in Table 13-7 and Table 13-8. The test results indicate the following: „ The BWi for the plus 16mm sorted product was higher than the composite samples prepared from the crushed products. Hence, it is reasonable to conclude that the uncrushed material in the HPGR is harder than the crushed product. „ The rejected plus 16mm material has a BWi harder than the composite sample and harder than the plus 16mm sorted product. „ The BWi for the products ranged from 23.1 to 24.28. A BWi of 24.5 was selected for the design of the primary ball mill circuit. Table 13-7: Bond Ball Mill Work Indices for Composite Samples Composite BWi (kwh/mt) 1 23.10 2 24.41 3 23.79 4 24.48 Table 13-8: Bond Ball Mill Work Indices for Ore Sorting Products and Wastes No. Composite Sample BWi (kwh/mt) Average BWi 1 1 1.1 XRT Product 23.0 2 1 2.1 XRT Product 25.15 24.71 3 1 3.1 XRT Product 25.98 4 2 4.1 XRT Product 26.55 5 2 5.1 XRT Product 26.91 26.63 6 2 6.1 XRT Product 26.44 7 3 7.1 XRT Product 24.54 8 3 8.1 XRT Product 24.63 24.87 9 3 9.1 XRT Product 25.44 10 4 10.1 XRT Product 25.37 11 4 11.1 XRT Product 25.89 25.62 12 4 12.1 XRT Product 25.61 13 2 4.2 Laser Waste 26.34 14 4 10.2 Laser Waste 23.89 15 Composite Sample (before HPGR 25.01

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 148 13.3.8 Leach Tests Several series of leach tests were performed to evaluate the effect of grind size, leach pulp density, cyanide concentration and two-stage grind on the gold extraction and reagent consumption. The test procedure consisted of grinding the ore to the desired particle size in a single stage or two stages as would be done in the plant and the ground pulp was transferred to a bottle. The pulp density was adjusted to the desired level and then the pH was adjusted to 11 with hydrated lime. The slurry was pre-aerated for 4 hours with 50ppm lead nitrate. Sodium cyanide was then added to a calculated level of cyanide concentration. The pH and cyanide concentration were determined at 6 and 24 hours and a sample of solution was taken and assayed for gold and silver. Activated carbon was added at 24 hours at a level of 20g/L. After 30 hours, the solution was measured to determine pH, free cyanide, and gold and silver content. The carbon was screened and dried. The slurry was filtered, washed and dried. The products were prepared and assayed for gold and silver. The test results are summarized in Table 13-9 to Table 13-13. The test results indicate the following: „ The gold extraction is size dependent. The finer the grind size, the higher the gold extraction. „ The gold extraction for average grade composites 1 and 4 were 82.8% to 87.6% at a P80 of 46 μm in a single-stage grind. However, for two-stage grind to P80 of 53 μm, the gold extraction improved from 86.4% to 89.7%. „ The NaCN consumption in the two-stage grind tests was also lower by ± 20% as compared to single-stage grind. „ The preliminary optimization study indicated that the leach circuit could potentially operate at higher pulp density (± 50% solids) and lower cyanide concentration (750 ppm initial concentration) without impacting gold extraction. Table 13-9: Gold Extraction vs. Grind Size for the Four Composites Test No. Composite P80, mesh Extraction % Au (30 hrs.) Residue g/t Au Cal. Head g/t Au Consumption Kg/t NaCN Lime 1 1 200 84.4 0.12 0.75 0.515 3.782 2 1 200 84.9 0.10 0.68 0.512 3.000 3 1 230 85.1 0.10 0.65 0.471 3.351 4 1 230 85.4 0.10 0.66 0.514 2.987 5 1 325 85.1 0.10 0.66 0.516 3.578 6 1 325 87.6 0.10 0.77 0.515 3.446 13 2 200 77.0 0.10 0.42 0.336 3.743 14 2 200 76.4 0.10 0.44 0.393 3.460 15 2 230 77.3 0.10 0.45 0.393 3.533 16 2 230 75.1 0.11 0.44 0.394 3.493 17 2 325 68.3 0.16 0.50 0.453 3.631 18 2 325 75.5 0.12 0.48 0.453 3.678 19 3 200 65.2 0.10 0.30 0.456 4.554

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 149 Test No. Composite P80, mesh Extraction % Au (30 hrs.) Residue g/t Au Cal. Head g/t Au Consumption Kg/t NaCN Lime 20 3 200 64.0 0.10 0.27 0.397 4.545 21 3 230 66.5 0.10 0.29 0.454 4.555 22 3 230 69.8 0.09 0.29 0.396 4.678 23 3 325 69.8 0.08 0.27 0.454 4.700 24 3 325 70.0 0.08 0.27 0.454 4.632 7 4 200 80.0 0.13 0.65 0.551 3.237 8 4 200 79.7 0.14 0.71 0.516 2.992 9 4 230 81.8 0.14 0.75 0.576 2.980 10 4 230 82.9 0.12 0.72 0.513 3.008 11 4 325 82.8 0.12 0.72 0.575 3.458 12 4 325 84.1 0.10 0.66 0.576 2.939 NOTE: Lime Consumption was assumed to be the same as lime addition to the test. Table 13-10: Gold Extraction at P80 of 270 mesh (53μm) with Two-stage Grind for the Four Composites Test No. Composite Extraction % Au (30 hrs.) Residue g/t Au Cal. Head g/t Au Consumption Kg/t NaCN Lime 25 1 86.6 0.09 0.67 0.393 4.972 26 1 86.2 0.09 0.67 0.336 4.866 27 2 85.8 0.06 0.44 0.398 4.446 28 2 85.2 0.07 0.44 0.458 4.529 29 3 80.1 0.06 0.31 0.514 4.773 30 3 80.5 0.06 0.32 0.513 4.930 31 4 86.1 0.10 0.69 0.392 4.521 32 4 86.4 0.09 0.68 0.397 4.501 NOTE: Lime Consumption was assumed to be the same as lime addition to the test.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 150 Table 13-11: Effect of Pulp Density and NaCN Concentration on Gold Extraction for Composite No. 1 at P80 of 270 mesh (53μm) with Two-stage Grinding Test No. Composite NaCN g/t Pulp Density % Solids Extraction % Au (30 hrs.) Residue g/t Au Cal. Head g/t Au Consumption Kg/t NaCN Lime 62 1 1.0 40 87.8 0.08 0.65 0.399 3.010 63 1 1.0 40 88.8 0.08 0.67 0.399 3.003 64 1 1.0 45 89.1 0.07 0.66 0.273 3.008 65 1 1.0 45 88.7 0.07 0.64 0.271 3.011 66 1 0.75 45 87.5 0.08 0.63 0.270 3.028 67 1 0.75 45 88.4 0.07 0.62 0.221 3.024 68 1 0.5 45 88.8 0.07 0.64 0.210 3.007 69 1 0.5 45 88.4 0.08 0.65 0.212 3.007 70 1 1.0 50 89.5 0.07 0.66 0.305 3.021 71 1 1.0 50 89.7 0.07 0.63 0.344 3.015 NOTE: Lime Consumption was assumed to be the same as lime addition to the test. Table 13-12: Effect of Pulp Density and NaCN Concentration on Gold Extraction for Composite No. 3 at P80 of 270 mesh (53μm) with Two-stage Grinding Test No. Composite NaCN g/t Pulp Density % Solids Extraction % Au (30 hrs.) Residue g/t Au Cal. Head g/t Au Consumption Kg/t NaCN Lime 82 3 1.0 40 84.7 0.04 0.25 0.460 3.011 83 3 1.0 40 84.9 0.04 0.25 0.272 3.011 84 3 1.0 45 84.7 0.04 0.25 0.271 3.010 85 3 1.0 45 84.8 0.04 0.25 0.372 3.010 86 3 0.75 45 83.2 0.04 0.24 0.269 3.017 87 3 0.75 45 86.3 0.03 0.25 0.322 3.010 88 3 0.50 45 83.8 0.04 0.25 0.211 3.011 89 3 0.50 45 84.4 0.04 0.24 0.211 3.016 90 3 1.0 50 85.0 0.04 0.25 0.347 3.011 91 1 1.0 50 84.9 0.04 0.25 0.346 3.011 NOTE: Lime Consumption was assumed to be the same as lime addition to the test.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 151 Table 13-13: Effect of Pulp Density and NaCN Concentration on Gold Extraction for Composite No. 4 at P80 of 270 mesh (53μm) with Two-stage Grinding Test No. Composite NaCN g/t Pulp Density % Solids Extraction % Au (30 hrs.) Residue g/t Au Cal. Head g/t Au Consumption Kg/t NaCN Lime 72 4 1.0 40 86.7 0.08 0.62 0.337 3.014 73 4 1.0 40 86.8 0.08 0.62 0.275 3.012 74 4 1.0 45 85.9 0.09 0.61 0.315 3.024 75 4 1.0 45 86.8 0.08 0.62 0.270 3.017 76 4 0.75 45 86.4 0.08 0.60 0.222 3.013 77 4 0.75 45 86.0 0.09 0.62 0.270 3.018 78 4 0.50 45 86.5 0.09 0.64 0.210 3.015 79 4 0.50 45 86.1 0.09 0.62 0.210 3.022 80 4 1.0 50 88.4 0.09 0.63 0.264 3.014 81 4 1.0 50 86.0 0.09 0.64 0.263 3.023 NOTE: Lime Consumption was assumed to be the same as lime addition to the test. 13.3.9 Cyanide Destruction The cyanide leach residue for composites No. 1 and No. 4 were subjected to cyanide destruction tests using the air/SO2 method. Approximately 1.5 liters of leach residue at 50% solids was agitated with sodium meta- bi-sulfite (SMBS) three times the stoichiometric amount of free cyanide and copper sulfate. Samples were taken every hour and free cyanide determined. Though no free cyanide was detected after one hour, the test was run for four hours. The cyanide specification before and after destruction for the two tests are given in Table 13-14. The test results indicate the following: „ The air-SO2 process successfully reduced CNWAD to levels of <10 ppm. „ There is sufficient dissolved copper in solution for precipitation of copper iron cyanide compounds in the earlier years of operation. Hence, addition of copper sulfate may not be needed. „ One hour of detox residence time is sufficient for the process. Table 13-14: Cyanide Destruction Test Results Forms of Cyanide ppm Composite 1 Composite 4 Before After Before After Free 600 6.3 590 4.0 Total 587 3.6 615 2.2 WAD 590 5.0 560 2.6

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 152 13.3.10 Thickening Tests Thickening tests on leach residue having a grind size of P80 of 53 μm generated in two-stages of grinding were performed for the four composites. The test results, given in Table 13-15, indicate the following: „ Approximately 8 g/t of high molecular weight low anionic acrylamide/sodium acrylate flocculant will be required for the settling of the slurry. „ Unit area required to settle the slurry to 45% solids ranges from 0.044 to 0.182 m2/mt/day. „ The unit area requirements increase significantly if the desired underflow solids is 50%. Table 13-15: Unit Area Requirements for Thickener for Composite Samples Composite P80, μm pH Flocculent Feed % Solids Unit Area Required m2/mt/day 40% 45% 50% 55% 1 53 11 8 g/t DAF-10 25 0.031 0.044 0.164 2.41 2 53 11 8 g/t DAF-10 25 0.050 0.069 0.150 2.448 3 53 11 8 g/t DAF-10 25 0.042 0.081 0.191 2.436 4 53 11 8 g/t DAF-10 25 0.083 0.182 0.650 2.425 13.4 2018/2019 Metallurgical Test Work The gold grades of the initial composites tested in 2017 metallurgical program were lower than the projected grades for the samples based on the grades being projected from the 3D resource model. Vista engaged in a detailed review to determine why the grade difference existed and found that by drilling the core zone at an oblique angle too few veins were intersected to provide a representative sample and, therefore, provided a biased result. The following table presents the average vein intercept angles for each of the drill holes completed. Table 13-16: Metallurgical Drilling Intercept Angle to Mineralized Vein BHID Average intercept angle VB17-001 10 degrees VB17-003 20 degrees VB17-002 40 degrees VB16-002 40 degrees Vista initiated an additional drilling program to address two specific questions, namely, whether the geological model is correct or not and how would higher grade material perform in the proposed process flowsheet. The drilling program was initiated in December 2017 and completed in January 2018. The 2017/2018 PQ metallurgical drill holes VB17-004, VB18-001, -002 and-003 were drilled approximately perpendicular to the mineralized host orientation and targeted similar locations to the 2016/2017 metallurgical samples. In addition, in order to test the accuracy of the resource model, the drill holes were drilled between known

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 153 resource model drill holes. The following table details the results of this drilling as compared to the existing drilling that was on either side of the new metallurgical drill hole. Figure 13-2 shows the location of the metallurgical drillholes. Figure 13-3 illustrates the relationship of the resource model estimated grades nearest existing drill hole intercept grades and the grades of the metallurgical hole VB17-004 to the two proximal drillholes VB08-030 and VB08-032. The average grade of the composites and kriged blocks are shown as the drillholes transit through a high grade zone. Table 13-17: Vista Drillholes and their Metallurgical Twins DH Drill Hole ID HG Core Length (m) Composite (g Au/t) Block Model (g Ault) Existing VB08-030 116 1.46 1.76 New Met VB17-004 113.5 1.461 1.45 Existing VB08-032 117 1.829 1.67 Existing VB07-001 126 1.879 1.44 New Met VB18-001 132 1.13 1.52 Existing VB08-028 129 1.739 1.59 Existing VB07-018 111 1.935 1.58 New Met VB18-002 110.7 1.499 1.56 New Met VB18-003 141 1.1 1.13 Existing VB07 -018 135 1.72 1.55 Total/Avg 1,231.20 1.57 1.52 Source: Tetra Tech, 2020 Figure 13-2: Drillhole Trace of VB08-030, VB17-001 and VB08-012

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 154 Source: Tetra Tech Figure 13-3: Drill hole trace of drillholes VB08-030, VB17-001 and VB08-012 A quarter split of the PQ core was assayed generally in one-meter lengths per the approved assay procedure. Based on the assay results, the following composites were prepared targeting the grade ranges that Vista desired for test work: „ 2.5 metric tons of composite sample designated "Big Yellow" and assaying 1.7 g/t Au. „ 2.5 metric tons of composite sample designated "Big Blue" and assaying 1.4 g/t Au. „ 1.0 metric ton of composites sample designated "Weir" and assaying 0.99 g/t Au. „ 40 kgs each of composite samples designated "small yellow", "small blue" and "small red" assaying 1.27 g/t Au, 0.84 g/t Au and 1.02 g/t Au, respectively. The Big Yellow and Big Blue composites were subjected to HPGR crushing and ore sorting whereas the Weir composite was subjected to only HPGR crushing. All the products from the HPGR and ore sorting tests were shipped to RDi for subsequent metallurgical test work. The remaining three samples were shipped to RDi and were not subjected to HPGR crushing or sorting. The samples from 2017 drilling, namely Composites 1 to 4, were also utilized in the 2018/2019 metallurgical test program.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 155 13.4.1 HPGR Testing at Thyssen-Krupp Industries (TKI) The two 2.5 mt composite samples, Big Yellow and Big Blue, were sent to TKI in Germany for the HPGR crushing component of the test program. The test program was identical to that performed in 2017 and produced similar results. The samples were jaw crushed followed by HPGR. The material balance is given in Table 13-18. The specific throughput rate was ±300 ts/hm3. Table 13-18: Material Balance for HPGR Tests at TKI Composite Sample Weight, kg HPGR Products, % +16mm -16 mm Biq Yellow 2400 18.6 81.4 Biq Blue 2370 17.8 82.2 13.4.2 HPGR Testing at WEIR Minerals Approximately 1 mt of drill core was also sent to WEIR minerals for evaluating the WEIR Enduron HPGR for Mt Todd ore. The drill core was pre-crushed with a jaw crusher and fed to HPGR in three batches and screened at 16 mm. The three HPGR runs delivered consistent and repeatable results. The specific energy showed little variation around the average of 1.94 kwh/t and the average specific throughput was 254 ts/hm3. The average mass oversize at 16 mm screen was 17.3%. The results were similar to the HPGR testing at TKI. 13.4.3 Tomra/Outotec Ore Sorting Test Work The plus 16 mm screened samples from TKI were sent to Tomra for ore sorting test work. The sorting tests were completed on the same XRT and laser equipment as the tests completed in 2017 (Section 13.3.2). The test results are given in Table 13.17. The test results indicate the following: „ The calculated head analyses of the plus 16 mm fraction for both composites were almost identical (0.731 g/t Au and 0.737 g/t Au). This has been determined to be due to the "softer" vein material preferentially crushing into finer material leaving the same approximate grades for the material with vein selvages on them going to sorting. „ The final rejection fraction was 54.5% for blue composite and 47.2% for yellow composite. „ Based on the assays of the various products, ore sorting rejected 8.7% and 7.9% of the feed for Big Yellow and Big Blue samples, respectively. The corresponding rejection of gold in the waste material was 0.9% and 0.7%. The gold loss was lower than 1.3% which was achieved in the 2017 test program

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 156 Table 13-19: Tomra Ore Sorting Test Results XRT Cut Laser Cut Test Units Total Mass Wt Au (g/mt) Ag (g/mt) Cu (mg/kg) CN Soluble Au (ppm) CN Soluble Ag (ppm) CN Soluble Cu (ppm) Sulfur (%) Wt Au (g/mt) Ag (g/mt) Cu (mg/kg) CN Soluble Au (ppm) CN Soluble Ag (ppm) CN Soluble Cu (ppm) Sulfur (%) Blue Composite XRT Sensitivity at X% 1.1 kg 193.6 98 1.262 0.6 716 0.78 0.28 253 1.49 4.6 0.734 0.6 504 0.48 0.28 179 0.48 % 100% 50.6% 87.4% 60.0% 77.1% 90.9% 84.8% 78.8% 80.7% 2.4% 2.4% 2.8% 2.5% 2.6% 4.0% 2.6% 1.2% XRT Sensitivity at X% 2.1 kg 167.1 56 2.599 1.0 794.0 1.8 0.5 307 .0 1.72 5.6 1.454 0.8 636 1.2 0.38 286 0.71 % 100% 33.5% 78.1% 54.5% 62.4% 78.6% 74.1% 64.7% 67.6% 3.4% 4.4% 4.4% 5.0% 5.2% 5.2% 6.0% 2.8% Blue Comp Total kg kg 361 154 10 % 100% 42.7% 2.80% Yellow Composite XRT Sensitivity at X% 3.1 kg 249.6 132.5 1.255 0.8 540 0.92 0.44 236 1.5 6.1 0.898 1 586 0.84 0.52 299 0.63 % 100% 53.1% 90.4% 59.3% 71.9% 91.2% 77.9% 73.5% 80.8% 2.4% 3.0% 3.4% 3.6% 3.8% 4.2% 4.3% 1.6% XRT Sensitivity at X% 4.1 kg 161.1 73.5 0.905 0.8 664 0.8 0.5 312 2.02 4.6 2.257 1.4 672 2.12 0.84 404 0.65 % 100% 45.6% 52.4% 51.1% 71.8% 55.1% 57.1% 72.3% 80.8% 2.9% 8.2% 5.6% 4.5% 9.1% 6.5% 5.9% 1.6% Yellow Comp Total kg kg 411 206 11 % 100% 50.2% 2.60% Final Rejects Sum - Head Grade Test Units Total Mass Wt Au (g/mt) Ag (g/mt) Cu (mg/kg) CN Soluble Au (ppm) CN Soluble Ag (ppm) CN Soluble Cu (ppm) Sulfur (%) Wt Au (g/mt) Ag (g/mt) Cu (mg/kg) CN Soluble Au (ppm) CN Soluble Ag (ppm) CN Soluble Cu (ppm) Sulfur (%) Blue Composite XRT Sensitivity at X% 1.1 kg 193.6 91 0.158 0.4 204 0.06 0.04 64.1 0.36 193.6 0.731 0.5 470.3 0.4 0.2 162.45 0.93 % 100% 47.0% 10.2% 37.2% 20.4% 6.5% 11.2% 18.5% 18.1% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% XRT Sensitivity at X% 2.1 kg 167.1 105.5 0.309 0.4 220 0.2 0.08 73.6 0.4 167.1 1.115 0.6 426.3 0.8 0.2 158.94 0.85 % 100% 63.1% 17.5% 41.1% 32.6% 16.3% 20.7% 29.2% 29.6% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% Blue Comp Total kg kg 361 197 361 % 100% 54.5% 100.0% Yellow Composite XRT Sensitivity at X% 3.1 kg 249.6 111 0.11 0.6 220 0.06 0.12 85.2 0.39 249.6 0.737 0.7 398.8 0.5 0.3 170.48 0.99 % 100% 44.5% 6.6% 37.3% 24.5% 5.0% 17.8% 22.2% 17.6% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% XRT Sensitivity at X% 4.1 kg 161.1 83 0.604 0.6 194 0.46 0.26 83.3 0.39 161.1 0.789 0.7 422.1 0.7 0.4 196.8 1.14 % 100% 51.5% 39.5% 43.3% 23.7% 35.8% 36.4% 21.8% 17.6% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% Yellow Comp Total kg kg 411 194 411 % 100% 47.2% 100.0%

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 157 13.4.4 Steinert Ore Sorting Test Work Under the direction of the QP [Deepak Malhotra, Ph.D., SME RM], RDi recombined the ore sorting samples from 2017 study discussed in Section 13.3.2 for evaluation at Steinert. Three samples (Composite1, 3 and 4) were sent to Steinert in Walton, Ky with the objective of evaluating the STEINERT combined sensor sorter (KSS FLI XT) for separating ore and waste. The test results, summarized in Table 13-20, were similar to those obtained at Tomra test facility in 2017.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 158 Table 13-20: Steinert Sorting Results for Composites 1, 3 and 4 Sample Wt (kg) Individual Wt% Cumulative Wt% Au Assay (g/mt) Individual Au Distribution % Cumulative Au Distribution % Ag Assay (g/mt) Individual Ag Distribution % Cumulative Ag Distribution % CN Soluble Cu Assay (ppm) Individual CN Cu Distribution % Cumulative CNCu Distribution % S Assay (%) Individual S Distribution % Cumulative S Distribution % Composite # 1 Product 1.1 3.8 3.2 3.2 3.711 45.7 45.7 2.0 12.9 12.9 428 14. 7 14 .7 6.25 32.2 32.2 Product 2.1 4.5 3.7 6.9 0.823 11.9 57.5 1.0 7.6 20.5 277 11.1 25.8 1.71 10.3 42.6 Product 3.1 11.1 9.3 16.2 0.322 11.5 69.1 0.6 11.3 31.8 141 14.0 39.8 0.70 10.5 53.1 Product 4.1 23.0 19.1 35.2 0.151 11.1 80.2 0.4 15.5 47.3 73.0 15.0 54.8 0.49 15.2 68.2 Product 5.1 32.0 26.6 61.9 0.075 7.7 87 .9 0.4 21.7 69.0 61.4 17.6 72.4 0.32 13.8 82.1 Waste 5.2 45.9 38.1 100.0 0.082 12.1 100.0 0.4 31.0 100.0 67.2 27.6 100.0 0.29 17.9 100.0 Total 120.4 100.0 0.259 100.0 0.5 100.0 92.9 100.0 0.62 100.0 Composite # 3 Pro duct 1.1 2.1 1.7 1.7 3.999 51.5 51.5 2.2 7.6 7.6 468 10 .9 10.9 5.54 28.7 28.7 Product 2.1 2.8 2.3 4.1 0.912 16.0 67.5 1.4 6.6 14.2 220 7.0 17.9 1.39 9.8 38.6 Product 3.1 8.6 7.2 11.3 0.185 10.0 77.5 1.0 14.5 28.7 129 12.6 30.S 0.68 14.8 53.3 Product 4.1 20.2 16.9 28.2 0.034 4.3 81.8 0.4 13.6 42.3 50.2 11.5 41.9 0.14 7.1 60.5 Product 5.1 30.7 25.6 53.8 0.034 6.5 88.3 0.4 20.6 62.9 61.6 21.4 63.3 0.17 13.1 73.6 Waste 5.2 55.2 46.2 100.0 0.034 11.7 100.0 0.4 37.1 100.0 58.8 36.7 100.0 0.19 26.4 100.0 Total 119.6 100.0 0.134 100.0 0.5 100.0 74.0 100.0 0.33 100.0 Composite # 4 Product 1.1 4.1 3.2 3.2 3.992 35.4 35.4 2.6 16.3 16.3 589 19.2 19.2 5.89 35.8 35.8 Product 2.1 5.1 4.1 7.3 0.85 7 9.5 45.0 1.0 7.9 24.1 306 12.5 31.8 1.20 9.1 44.9 Product 3.1 13.2 10.4 17.7 0.487 13.9 58.9 0.6 12.1 36.2 121 12.7 44.5 0.55 10.7 55.7 Product 4.1 23.9 18.8 36.5 0.322 16.6 75.5 0.4 14.6 50.8 56.8 10.8 55.3 0.31 11.0 66.6 Product 5.1 34.3 27.1 63.6 0.062 4.6 80.1 0.4 21.0 71.8 70.4 19.3 74.6 0.32 16.3 82.9 Waste 5.2 46.1 36.4 100.0 0.199 19.9 100.0 0.4 28.2 100.0 69.2 25.4 100.0 0.25 17.1 100.0 Total 126. 7 100 .0 0.364 100.0 0.5 100.0 99.0 100.0 0.53 100.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 159 13.4.5 Preparation of Composites for Metallurgical Test Work and Head Analyses The samples from HPGR and ore-sorting test work were prepared using the same protocol as used in 2017 study and discussed in Section 13.3.3. All the samples were submitted for head analyses. The test results, summarized in Table 13-21, indicate the following: „ Head analyses of some of the composite were close to expected values whereas for other samples, the assays were significantly different. „ The assayed values covered a range from 0.5 g Au/t to 2.95 g Au/t. Table 13-21: Head Analyses of Composite Samples Sample Expected Head Grade, g/tAu Multiple Head Grade Analyses, g/t Big Blue 1.39 0.91, 1.31 Biq Yellow 1.70 0.83, 1.68 Weir 1.00 1.05 Small Blue 0.84 2.60, 2.62, 2.95 Small Yellow 1.27 1.48, 0.67, 0.72 Small Red 1.02 0.44, 0.51, 0.65 13.4.6 Bond's Ball Mill Work Indices A Bond's ball mill work index (BWi) was determined at a grind size of P80 of 100 mesh for each of the three large samples (Big Yellow, Big Blue and Weir). The ore sorting waste was removed from the Big Yellow and Big Blue samples. The results are summarized in Table 13-22. The test result indicates the following: „ The BWi's for Big Yellow and Big Blue samples following the rejection of ore sorting waste were lower than Weir sample which represented the run-of-mine ore. „ The average BWi of the two composites (Big Yellow and Big Blue) was 24.3 which is similar to the valve selected for mill design. Table 13-22: Bond's Ball Mill Work Indices for Composite Samples Composite BWi (kwh/mt) Big Yellow 25.08 Biq Blue 23.41 Weir 25.81

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 160 13.4.7 Primary Grind Earlier studies had indicated that the selected circuit would require three of the largest-size manufactured ball mills to achieve a targeted grind of P80 of 90 microns. The concept of two stage grinding was developed with the idea of using the HPGR crushers to generate a smaller product size. This allowed the three large ball mills to be replaced by two smaller ball mills for the first stage of grinding and to produce a product with a P80 of 250 microns. This first stage of grinding could then be followed by removal of finished product and regrinding the coarse material to the desired product size in a stirred media mill. The primary grind size in the present study remained the same as the 2017 study (P80 of 250 microns). 13.4.8 Fine Grind The 2017 study confirmed that gold extraction was size dependent, as also observed in historic metallurgical work. The finer the grind size, the higher the gold extraction. Fine grind testing had been initiated to evaluate ISA mills and FLS VXP mills for the January 2018 Technical Report. However, since the results of the test work was not available until March 2018, ISA mills were selected for the PFS study. The test results for Composites 1 to 4 indicated that FLS VXP mills used significantly less energy (±15 kwh/t) to achieve P80 of 60 microns as compared to ISA mills that require ±28 kwh/t. Several additional studies were undertaken at FLS facilities for VXP testing and Core labs in Australia and SGS Canada for ISA mill testing. The targeted grind size was reduced to 40 microns in 2019 study. The following conclusions were drawn from the fine grind studies at the above-mentioned laboratories and RDi: „ The Malvern particle size analyzer did not provide an accurate analysis of the particle size distribution for the ground products. Hence, additional testing was undertaken on both machines, and products were screened in order to obtain accurate energy requirements and product for cyanide leach testing. „ FLS estimated specific energy requirements between 16.7 and 17.4 kwh/t to achieve P80 of 40 microns. „ SGS signature plots for the same samples tested at FLS facility indicated specific energy requirements between 26 and 34 kwh/t. The specific energy requirements for VXP mill are significantly lower because the mill is vertical and the flow of material upward through the mill results in the finer material being carried up and out of the mill more quickly, while the coarser particles remain subject to additional grinding. In contrast, the IsaMill is a horizontal mill and the flow of material is more homogeneous and of a more fixed duration. This helps explain the IsaMill being more commonly used to produce a finer product than Vista is targeting. Due to the significantly lower power requirement, the ISA Mills were replaced with FLS VXP mills in the present study.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 161 13.4.9 Leach Feed Thickener Since the leach feed size was changed from P80 of 60 microns to 40 microns, additional thickening tests were undertaken at Pocock Industrial and RDi. Based on the test results, the thickener size was changed from 45 meter diameter to 67 meter diameter in the process flowsheet. 13.4.10 Leach Agitator Design and Power Requirements SPX Flow Lightnin performed test work on the ground slurry to determine full scale sizing for the leach conditioning and leach tank agitators in April 2018 Their recommendations were incorporated into the process flowsheet. 13.4.11 Leach Tests Several series of leach tests were performed with the six samples in the present study. The test procedure consisted of grinding the ore to the desired particle size in a single stage or two stages as would be done in the plant and the ground pulp was transferred to a bottle. The pulp density was adjusted to the desired level and then the pH was adjusted to 11 with hydrated lime. The slurry was pre-aerated for 4 hours with 50ppm lead nitrate. Sodium cyanide was then added to a calculated level of cyanide concentration. The pH and cyanide concentration were determined at 6 and 24 hours and a sample of solution was taken and assayed for gold and silver. Activated carbon was added at 24 hours at a level of 20g/L. After 30 hours, the solution was measured to determine pH, free cyanide, and gold and silver content. The carbon was screened and dried. The slurry was filtered, washed and dried. The products were prepared and assayed for gold and silver. The primary objective of the leach tests was to evaluate the effect of feed grade on gold extraction at grind sizes of P80 of 53 microns and finer. The feed gold grades were divided into the following ranges: „ Greater than 1.5 g/t Au „ 1.0 to 1.5 g/t Au „ 0.8 to 1.0 g/t Au „ 0.6 to 0.8 g/t Au „ 0.4 to 0.6 g/t Au „ Less than 0.4 g/t Au The test results for 71 leach tests are summarized in Table 13-23 to Table 13-28. The test results indicate the following: „ Gold extraction of over 90% was obtained for feed grades of 0.6 g/t Au or higher. „ The higher the feed grade, the higher the gold extraction.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 162 Table 13-23: Leach Results for Feed Grade >1.5 g/t Au Test# P80 Particle Size (μm) % Recovery (Au) Calc. Head Grade (g Au/t) Residue Grade (g Au/t) +1.5g Au/t BR113 101 86.1 1.77 0.25 BR114 101 85.4 1.77 0.26 BR119 91 87.6 1.82 0.23 BR120 91 88.9 1.74 0.19 BR117 76 87.3 1.74 0.22 BR118 76 87.0 1.70 0.22 BR116 74 87.0 1.70 0.22 BR115 74 86.4 1.67 0.23 BR153(1) 53 93.6 1.96 0.12 BR154(1) 53 93.6 1.90 0.12 BR196 31 90.3 1.73 0.17 BR195 31 90.4 1.69 0.16 BR204 22 93.1 1.70 0.12 BR205 22 93.0 1.63 0.11 BR201 19 91.8 1.56 0.13 <53 micron average values 92.3 0.13 Table 13-24: Leach Results for Feed Grade of 1.0 to 1.5 g/t Au Test# P80 Particle Size ( μm) % Recovery (Au) Calc. Head Grade (g Au/t) Residue Grade (g Au/t) >=1.0g Au/t < 1.5g Au/t BR122 97 84.6 1.24 0.19 BR121 97 86.6 1.20 0.16 BR123 74 89.1 1.26 0.14 BR124 74 87.5 1.21 0.15 BR144 59 84.9 1.21 0.18 BR143 59 84.8 1.17 0.18 BR197 29 90.4 1.21 0.12 BR198 29 90.1 1.16 0.11 BR206 20 92.7 1.10 0.08 BR207 20 92.7 1.09 0.08 <53 micron average values 91.5 0.10

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 163 Table 13-25: Leach Results for Feed Grade of0.8 to 1.0 g/t Au Test# Particle Size (Pso μm) % Recovery (Au) Calc. Head Grade (g Au /t) Residue Grade (g Au /t) >=0.8g Au/t < 1.0g Au/t BR126 87 85.5 0.88 0.13 BR125 87 86.5 0.87 0.12 BR128 79 88.4 0.89 0.10 BR127 79 87.4 0.86 0.11 BR147 69 85.5 0.95 0.14 BR148 69 85.0 0.91 0.14 BR130 69 86.9 0.86 0.11 BR129 69 89.1 0.83 0.09 BR158 59 87.4 0.93 0.12 BR199 35 89.5 0.9 0.09 BR200 35 89.6 0.85 0.09 BR209 22 91.8 0.88 0.07 BR208 22 91.9 0.84 0.07 <53 micron average values 90.7 0.08 Table 13-26: Leach Results for Feed Grade of 0.6 to 0.8 g/t Au Test# Particle Size (P80 μm) % Recovery (Au) Calc. Head Grade (g Au /t) Residue Grade (g Au /t) >=0.6g Au/t < 0.8g Au/t BR104 70 85.3 0.63 0.09 BR105 70 84.9 0.61 0.09 BR106 70 84.1 0.61 0.10 BR157 59 88.S 0.77 0.09 BR162(1) 52 92.3 0.73 0.06 BR161(1) 52 91.4 0.72 0.06 BR96 49 89.9 0.68 0.07 BR95 49 89.6 0.66 0.07 BR97 49 89.5 0.66 0.07 BR101 39 90.5 0.65 0.06 BR102 39 90.9 0.64 0.06 BR103 39 90.4 0.64 0.06 BRlO0 36 92.1 0.79 0.06

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 164 Test# Particle Size (P80 μm) % Recovery (Au) Calc. Head Grade (g Au /t) Residue Grade (g Au /t) BR98 36 88.3 0.70 0.08 BR99 35 89.7 0.73 0.08 BR109 18 94.0 0.69 0.04 BR107 18 89.4 0.68 0.07 BR108 18 93.8 0.66 0.04 BRlll 15 91.0 0.61 0.06 BRll0 15 92.0 0.60 0.05 BR112 15 90.9 0.60 0.06 <53 micron average values 90.9 0.06 Table 13-27: Leach Results for Feed Grade of 0.4 to 0.6 g/t Au Test# P80 Particle Size (μm) % Recovery (Au) Calc. Head Grade (g Au /t) Residue Grade (g Au /t) >=0.4g Au/t < 0.6g Au/t BR131 59 84 .8 0.46 0.07 BR132 59 86 .2 0.46 0.06 BR165 56 83.6 0.52 0 .08 BR166 56 85 .0 0.52 0.08 BR210 22 88.S 0.42 0.05 BR211 22 89.0 0.41 0.05 <53 micron average values 88.8 0.05 Table 13-28: Leach Results for Feed Grade of <0.4 g/t Au Test# P80 Particle Size (μm) % Recovery (Au) Calc. Head Grade (g Au /t) Residue Grade (g Au /t) < 0.4g Au/t (below cutoff) BR167 60 81.6 0.18 0.03 BR212 60 80.6 0.18 0.03 BR213 49 85.8 0.32 0.05 BR168 49 78.S 0.21 0.04 BR133 21 87.S 0.26 0.03 BR134 21 86.9 0.26 0.03 <53 micron average values 84.7 0.04

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 165 „ The average gold extraction, irrespective of the feed grade, at P80 of 53 microns or fine was 90.4% on a non-weighted average basis. The actual final recovery was determined on a weighted average basis. „ The cyanide consumption for all tests with particle size of 59 microns or finer averaged 0.636 kg/t (47 tests). Assuming a residual cyanide of 200 ppm and leach tests at 45% solids, the total cyanide consumption would be 0.876 kg/t. This assumes no cyanide recycle in the process. „ The average lime consumption in the 47 leach tests was 4.64 kg/t. Assuming that once the tailing pond stabilizes, the lime consumption will only be 60% of the consumption with tap water. Hence, the lime consumption is reduced to 2.8 kg/t after 3 months of operation. „ The fine grind products received from FLS and Core Laboratories that did not meet the targeted size were reground in ball mill with steel media at RDi. The cyanide consumption for samples ground with steel media was significantly higher than those ground with ceramic media. Hence, ceramic media is recommended for regrind mills in the flowsheet. „ The average leach residue assay for the different range of ore grades is given in Table 13-29. This data can be used by the process engineer to predict gold extraction in the plant. Table 13-29: Leach Residue Assay Versus Ore Feed Grade Ore, g Au/t Leach Residue, g Au/t >1.5 0.13 1.0-1.5 0.10 0.8-1.0 0.08 0,6-0.8 0.06 0.4-0.6 0.05 <0.4 0.04 13.4.12 Thickening Tests on Leach Residue Thickening tests were performed at Pocock Industrial Inc. on leach residue having a P80 of 53 microns and 37 microns. The test results indicated that the maximum underflow density of 55% could be achieved but would require a significantly larger size thickener than determined in the previous study. A trade-off study between savings in recycling cyanide and Capex required for larger thickener was undertaken. A decision was made not to have a thickener for densifying leach residue in the circuit. 13.4.13 Cyanide Destruction The cyanide leach residue having a P80 of 45 micrometer and free cyanide of 200 ppm was subjected to cyanide destruction using the air/SO2 method discussed in Section 13.3.9.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 166 The forms of cyanide before and after destruction for the test is given in Table 13-30. The test results indicate that the air/SO2 process will reduce the cyanide to below environmentally acceptable levels. Table 13-30: Cyanide Destruction Test Results Forms of Cyanide Before After Free, ppm 130 0.036 Total, ppm 124 0.062 WAD, ppm 132 0.048 13.5 Process Flowsheet The process flowsheet given in Figure 13-4 and Figure 13-5 has significant advantages over the process flowsheet provided in the NI 43-101 Technical Report – Mt Todd Gold Project, 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia; March 2, 2018. The samples tested in the 2017 and 2018/2019 programs are believed to be representative of the deposit as stated in Sections 13.3 and 13.4 . These composites were selected to represent both near term and longer-term mining and spastically located to provide variability both horizontally and vertically. The recovery was estimated from the leach test results for the various composites given in Table 13-22 to Table 13-27 based on the proportion of each composite over the life of the mine. The only deleterious element in the deposit will be oxide and secondary copper which increases the cyanide consumption but will not impact gold extraction. Though the amount of oxide and secondary copper decreases with depth, the cyanide consumption was not corrected for it. Therefore, the cyanide consumption is conservatively estimated. These results have not been compiled in the final metallurgical report which will be issued by RDi later this year. The significant changes confirmed in the recent testwork and maintained in the process flowsheet include the following: „ Ore sorting of the coarse HPGR product which rejects ± 10% of the feed as waste product. „ Fine crushing and two-stage grinding with classification at each stage which reduces the quantity of material that needs to be ground in the second stage. These modifications, along with finer grind of P80 of 40 microns, have resulted in producing much finer product to the leach circuit. This has resulted in enhancing gold extraction by ± 5.5%.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 167 Source: Resource Development Inc, September 2019 Figure 13-4: Conceptual Process Flowsheet for Mt Todd Ore (1/2)

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 168 Source: Resource Development Inc, September 2019 Figure 13-5: Conceptual Process Flowsheet for Mt Todd Ore (2/2)

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 169 14.0 MINERAL RESOURCE ESTIMATES 14.1 Introduction The following sections summarize the thought process, procedures, and results of the QP’s [Rex Clair Bryan, Ph.D., SME RM] independent estimate of the contained gold resources of the: 1) Batman Deposit 2) Quigleys Deposit 3) Heap Leach Pad Only these three deposits currently have resource estimates classified in accordance with CIM Standards. Each of the mineral resources for the Batman and Quigleys deposits have been reported within a shell generated using WhittleTM, 4-D Lerchs-Grossman algorithm. Mineral resources within such a shell are not mineral reserves and do not demonstrate economic viability. The QP confirms that the Batman mineral resource presented in this report and the January 2018 PFS are the same and unchanged. No additional mineral resource drilling occurred in the Batman deposit or for the heap leach pad between the January 2018 PFS and the effective date of this report. While diamond core drilling did occur during this time, this drilling was for metallurgical samples and not applicable to mineral resource or reserves definition. The Quigleys resource has been updated to reflect a gold price of $1,300/oz. The selection of using a 0.4 g/t cutoff for gold is detailed in Section 15.1.1. It is the opinion of the QP for this section that the reported mineral resource classifications comply with current CIM definitions for each mineral class. Geostatistics resource estimation and 3-D visualization was done with various mining software. The primary software used were MicroModel®, MicroMine®, Vulcan®, GemCom® and Whittle TM. Additional statistical analysis was done with Statistica® and Excel®. Figure 14-1 shows the relative locations of the three resource estimations for the Project. The Batman deposit is located approximately 500 meters west of the original plant site, the Quigleys deposit and the Heap Leach Pad are north and south of the existing tailings area respectively. Table 14-1 summarizes the resources of each. Cautionary statements regarding mineral resource estimates: Mineral resources are not mineral reserves and do not have demonstrated economic viability. There is no certainty that all or any part of the mineral resources will be converted into mineral reserves. Inferred resources are that part of a mineral resource for which quantity and grade or quality are estimated on the basis of limited geological evidence and sampling. Geological evidence is sufficient to imply but not verify geological and grade or quality continuity. It is reasonably expected that the majority of inferred mineral resources could be upgraded to indicated mineral resources with continued exploration. All references to the term “ore” contained in this Technical Report refer to mineral reserves, not mineral resources.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 170 Figure 14-1: Drillhole Location Map Batman & Quigleys Deposits and Heap Leach Pad

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 171 Table 14-1: Summary of the Batman, Heap Leach Pad and Quigleys Deposits Batman Deposit Heap Leach Pad Quigleys Deposit Tonnes (000s) Grade (g/t) Contained Ounces (000s) Tonnes (000s) Grade (g/t) Contained Ounces (000s) Tonnes (000s) Grade (g/t) Contained Ounces (000s) Measured (M) 77,725 0.88 2,191 - - - 594 1.15 22 Indicated (I) 200, 112 0.80 5,169 13,354 0.54 232 7,301 1.11 260 Measured & Indicated 277,837 0.82 7,360 13,354 0.54 232 7,895 1.11 282 Inferred (F) 61,323 0.72 1,421 - - - 3,981 .46 187 NOTES: (1) Measured & indicated resources include proven and probable reserves. (2) Batman and Quigleys resources are quoted at a 0.40g-Au/t cut-off grade. Heap Leach resources are the average grade of the heap, no cut-off applied. (3) Batman: Resources constrained within a US$1,300/oz gold WhittleTM pit shell. Pit parameters: Mining Cost US$1.50/tonne, Milling Cost US$7.80/tonne processed, G&A Cost US$0.46/tonne processed, G&A/Year 8,201 K US4, Au Recovery, Sulfide 85%, Transition 80%, Oxide 80%, 0.2g-Au/t minimum for resource shell. Selling Cost: US$/oz recovered US412.00. (4) Quigleys: Resources constrained within a US$1,300/oz gold WhittleTM pit shell. Pit parameters: Mining cost US$1.90/tonne, Processing Cost US$9.779/tonne processed, Sale Cost US$/oz US$3.19, Royalty 1% NPR, Gold Recovery Sulfide, 82.0% and Ox/Trans 78.0%, water treatment US $ 0.09/tonne, Tailings $US 0.985/tonne (5) Differences in the table due to rounding are not considered material. Differences between Batman and Quigleys mining and metallurgical parameters are due to their individual geologic and engineering characteristics. (6) Rex Bryan of Tetra Tech is the QP responsible for the Statement of Mineral Resources for the Batman, Heap Leach Pad and Quigleys deposits. (7) Thomas Dyer of Mine Development Associates is the QP responsible for developing the resource WhittleTM pit shell for the Batman Deposit. (8) The effective date of the mineral resource estimate is September 2019. (9) Mineral resources that are not mineral reserves have no demonstrated economic viability and do not meet all relevant modifying factors. 14.2 Geologic Modeling of the Batman Deposit Gold mineralization in the Batman deposit at the Project occurs in sheeted veins within silicified greywackes/shales/siltstones. The Batman deposit strikes north-northeast and dips steeply to the east. Higher grade zones of the deposit plunge to the south. The core zone is approximately 200-250 meters wide and 1.5 km long, with several hanging wall structures providing additional width to the orebody. Mineralization is open at depth as well as along strike, although the intensity of mineralization weakens to the north and south along strike. The Batman deposit contains 94% of the gold resources classified as measured and indicated within the Project. Only the Batman resources have been furt her converted to classified reserves of proven and probable. Over several drilling campaigns, the shape of the mineralized shear zone has been adjusted and resized to accommodate this new data. Deeper step-out drilling by Vista indicated that the lower footwall of the core complex was previously not drill tested. The additional drilling confirmed the previously indicated higher grade plunge of the core complex. The new data was used to re-define the granite contact that constrains the lower footwall of the core complex. The granite contact is a mineral exclusionary zone and has been modeled as a triangulated surface, which can be seen in Figure 14-2.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 172 In addition to resizing the core complex wireframe solid, three structures paralleling the core complex to the east were also resized and constructed into wireframe solids and used for this resource estimate. The interpreted parallel structures represent an echoing of the main mineralization controls of the core complex nearer the surface and to the east. Wireframe solids for the parallel structures were interpreted on sections using Au mineralization, veining percentage, visual sulfide percentages, structural orientations and multi- element data. Deep drilling conducted in 2011 and through 2012 confirmed the existence of these structures and indicates a possible increasing definition and grade at depth. The Batman Deposit resource was updated to reflect the increase in available data provided by drilling conducted in 2015 through 2017. A redefinition of the geometry of a granite contact reducing primarily inferred resources at depth. A WhittleTM pit further constrained the reported resources. Figure 14-2 is a schematic of domain designations and crucial parameters used in the resource model. The figure lists the resource classification codes, the rock codes, density assignments. Also schematically shown are the constraining surfaces for current topography, levels of oxidation, granite basement and the US$1,300/oz gold pit shell constrain reported resources.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 173 Figure 14-2: Schematic of Codes and Surface Designations (Looking North)

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 174 Figure 14-3 shows a sectional view of the drillhole data at Batman. The direction of Batman Deposit drilling is dipping at approximately 45-degrees to the west. Figure 14-3: Sectional View of Drillhole Data 8,434,803 mN (Looking North)

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 175 14.2.1 Batman Deposit Density Data Drillhole data through 2012 for a total of 16,373 samples were tested for bulk density (diamond core). These bulk densities were carried out on a 10 to 15 centimeters (cm) piece of core from a 1-m sample. Based on this work, the bulk densities applied to the resource model are presented in Table 14-2. Table 14-2: Summary of Batman Bulk Density Data by Oxidation State Oxidation No. of Samples Min Max Mean Variance CV Oxide 2,341 1.77 3.28 2.47 0.04 0.08 Transitional 1,316 2.07 3.55 2.67 0.01 0.04 Primary 12,716 1.58 3.90 2.77 0.006 0.03 Since then, an additional 3,370 samples have confirmed these results for Primary material bulk density. 14.2.2 Grade Capping Review of the log probability plot of the composited gold grades shows that there is a distinct break in the distribution at 50 g-Au/t. All gold composites were capped at this value. Inspection of the cumulative frequency plot of data from the core domain codes 600, 700, 800 and 1000 suggest that the 1m assay values when composited to 4 m limits the higher gold grades to a maximum value of 10.9 g-Au/t. 14.3 Batman Block Model Parameters Table 14-3 details the physical limits of the Batman deposit block model utilized in the estimation of mineral resources. Table 14-3: Block Model* Physical Parameters – Batman Deposit Direction (dir) Minimum (m) MGA94 z53 Maximum (m) MGA94 z53 Block Size #Blocks y-dir 8,433,801 mE 8,436,213 mE 12 m 201 x-dir 185,999 mN 187,931 mN 12 m 161 z-dir -994 m 224 m 6 m 203 * Model changed from previous Tetra Tech estimates to reflect the 2011 drillhole locations and depths.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 176 14.3.1 Geostatistics of the Batman Deposit Geology of the Batman Deposit consists of a sequence of hornfelsed interbedded greywackes, and shales with minor thin beds of felsic tuffs. Minor lamprophyre dykes trending north-south crosscut the bedding. The mineralized lithologic package consists of a tabular deposit striking at 325o with a dip of 40o to 60o to the southeast. The majority of drilling slants at a dip of approximately 65o with an azimuth of 270o. Bedding parallel shears are present in some of the shale horizons (especially in lithologic units SHGW23, GWSH23, and SH22). These bedding shears are identified by quartz/calcite sulfidic breccias. Pyrite, pyrrhotite, chalcopyrite, galena, and sphalerite are the main primary sulfides associated with the bedding parallel shears. NE-SW trending faults and joint sets crosscut bedding. Only minor movement has been observed on these faults. Calcite veining is sometimes associated with these faults. These structures appear to be post mineralization. Northerly trending quartz sulfide veins and joints striking at 0o to 20o, dipping to the east at 60o, are the major location for mineralization in the Batman Deposit. The veins are 1 to 100 mm in thickness with an average thickness of around 8 to 10 mm. The veins consist of dominantly quartz with sulfides on the margins. The veining occurs in sheets with up to 20 veins per horizontal meter. These sheet veins are the main source of mineralization in the Batman Deposit. The mineralization within the Batman Deposit is directly related to the intensity of the north-south trending quartz sulfide veining. The lithological units impact on the orientation and intensity of mineralization. Sulfide minerals associated with the gold mineralization are pyrite, pyrrhotite and lesser amounts of chalcopyrite, bismuthinite and arsenopyrite. Galena and sphalerite are also present but appear to be post gold mineralization and are related to calcite veining bedding and the east-west trending faults and joints.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 177 Multiple directional variograms explored the best continuity of mineralization given the combination of control by bedding and sulfide veining. Figure 14-4 is an example of two log variograms in the core complex. Source: Tetra Tech, prepared in August 2017 Figure 14-4: Example Log Variograms of Gold within the Core Complex Table 14-4 shows the resource classification criteria and variogram for the Batman resource model.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 178 Table 14-4: Batman Resource Classification Criteria and Variogram Category Search Range & Kriging Variance No. of Sectors/ Max Points per DH Search Anisotropy Min Points Composite Codes Block Codes CORE Indicated Core Complex: 150 m & KV < 0.45 Pass 1 4/2 (1.0:0.7:0.4) [110:80:0] 2 1000 1000 CORE COMPLEX Measured Core Complex: 60 m & KV < 0.30) Pass 2 (overwrite Pass 1) 4/3 (1.0:0.7:0.4) [110:80:0] 4 1000 1000 inferred Core Complex KV >= 0.34 Classification Step 4/2 (1.0:0.7:0.4) [110:80:0] 2 1000 1000 inferred Outside Core Complex: 150 m & KV <= 0.45 Pass 3 4/3 (1.0:0.7:0.4) [110:80:0] 3 500/3500 500/ 3500 OUTSIDE CORE COMPLEX inferred Outside Core Complex: 50 m & KV > = 0.45 Pass 4 (overwrite Pass 3) 4/3 (1.0:0.7:0.4) [110:80:0] 8 500/3500 500/ 3500 inferred Primary Satellite Deposit: 150 m & KV >= 0.45 Pass 5 4/3 (1.0:0.7:0.4) [110:80:0] 3 600 600 Indicated Primary Satellite Deposit: 50 m & KV < 0.45 Pass 6 (overwrite Pass 5) 4/3 (1.0:0.7:0.4) [110:80:0] 8 600 600 inferred Secondary Satellite Deposit: 150 m & KV >= 0.45 Pass 7 4/3 (1.0:0.7:0.4) [110:80:0] 3 700 700 Indicated Secondary Satellite Deposit: 50 m & KV < 0.45 Pass 8 (overwrite Pass 7) 4/3 (1.0:0.7:0.4) [110:80:0] 8 700 700 inferred Tertiary Satellite Deposit: 150 m & KV >= 0.45 Pass 9 4/3 (1.0:0.7:0.4) [110:80:0] 3 800 800 Indicated Tertiary Satellite Deposit: 50 m & KV < 0.45 Pass 10 (overwrite Pass 9) 4/3 (1.0:0.7:0.4) [110:80:0] 8 800 800 VARIOGRAM FOR ALL CATEGORIES Type: Spherical Primary Axis: 150m Nugget: 0.6 First Rotation (Azimuth: 110) Secondary Axis: 105m Sill 1: 0.3 Range 1: 40m Second Rotation (Dip: 80) Tertiary Axis: 60m Sill 2: 0.2 Range 2: 500m Third Rotation (Tilt: 0)

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 179 INDEX Zone Codes Zone Names Notes 3500 Footwall Ranges In meters (m) KV = kriging variance, Passes refer to multiple re-estimations of blocks with greater constraints (minimum points, search ranges, etc.) imposed. Core and Satellites have more consistent gold grades, while the Footwall and Hanging Wall have patchy gold grades, Search Ranges (a:b:c) Proportion of Maximum Range for: a. Primary Axis Length: b. Secondary Axis Length: c. Tertiary Axis Length Orientation of Ellipse [1:2:3] 1. Azimuth of Primary Axis : 2. Dip of Primary Axis: 3. Rotation (Tilt) around Primary Axis 1000 Core Complex 800 Tertiary Satellite (between 600 and 700) 700 Secondary Satellite (in HW farthest from Core) 600 Primary Satellite (in HW nearest to Core) 500 Hanging Wall Area

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 180 Figure 14-5 through Figure 14-10 are a series of sections and plan views of the Batman deposit block model. Figure 14-5: Blocks Kriged Au – Cross-section 8,434,900 mN Looking North, Batman Deposit

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 181 Figure 14-6: Classified Blocks Measured, Indicated, and Inferred – Cross-section 8,434,900 mN Looking North, Batman Deposit

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 182 Figure 14-7: Blocks Kriged Au – Level Plan -100m msl Batman Deposit

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 183 Figure 14-8: Classified Blocks Measured, Indicated, and Inferred – Level Plan -100m msl Batman Deposit

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 184 Figure 14-9: Blocks Kriged Au – Long Section of the Core Complex Looking West

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 185 Figure 14-10: Classified Blocks Measured, Indicated, and Inferred – Long Section of the Core Complex Looking West Table 14-5 lists the current Batman measured and indicated resource estimates at cutoff grades ranging from 0.3 g-Au/t to 2.0 g-Au/t. Table 14-6 lists the current Batman inferred resource estimates at cutoff grades ranging from 0.3 g-Au/t to 2.0 g-Au/t. Figure 14-11 graphically shows the grade-tonnage for Measured plus Indicated classified Batman deposit resources.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 186 Table 14-5: Batman Deposit Measured and Indicated Gold Resource Estimate Cutoff Grade g-Au/t Tonnes (x1000) Average Grade g-Au/t Total Au Ounces (x1000) MEASURED 2.00 2,474 2.40 191.1 1.75 4,616 2.15 319.4 1.50 8,186 1.92 505.1 1.25 13,205 1.71 725.8 1.00 21,512 1.48 1,024.0 0.90 26,481 1.38 1,175.2 0.80 33,167 1.27 1,357.2 0.70 41,594 1.17 1,560.0 0.60 52,492 1.06 1,787.3 0.50 64,597 0.96 2,001.1 0.40 77,725 0.88 2,191.1 0.3 90,719 0.80 2,337.8 2.00 5,413 2.55 443 INDICATED 1.75 9,124 2.27 666 1.50 15,194 2.01 982 1.25 25,183 1.75 1,420 1.00 43,059 1.49 2,057 0.90 54,104 1.38 2,394 0.80 68,845 1.26 2,796 0.70 88,256 1.15 3,262 0.60 115,528 1.03 3,830 0.50 153,278 0.91 4,494 0.40 200,112 0.80 5,169 0.30 253,187 0.71 5,765 2.00 7,887 2.50 634 MEASURED + INDICATED 1.75 13,740 2.23 985 1.50 23,380 1.98 1,487 1.25 38,387 1.74 2,145 1.00 64,571 1.48 3,081 0.90 80,585 1.38 3,569 0.80 102,012 1.27 4,153 0.70 129,850 1.16 4,822 0.60 168,021 1.04 5,617 0.50 217,875 0.93 6,495 0.40 277,837 0.824 7,360 0.30 343,906 0.73 8,104 0.30 343,906 0.73 8,104 NOTE: (1) The measured and indicated resource estimates presented in this table include the proven and probable reserves presented in Section 15 of this Technical Report. (2) Mineral resources that are not mineral reserves have no demonstrated economic viability and do not meet all relevant modifying factors. (3) The effective date of the mineral resource estimate is September 2019.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 187 Source: Tetra Tech, Inc (August 2019) NOTE: Mineral resources that are not mineral reserves have no demonstrated economic viability and do not meet all relevant modifying factors. Figure 14-11: Grade Tonnage Curve of Measured and Indicated Resource for the Batman Deposit Table 14-6: Batman Deposit Inferred Gold Resource Estimate Cutoff Grade g-Au/t Tonnes (x1000) Average Grade g-Au/t Total Au Ounces (x1000) INFERRED 2.00 1,664 2.94 157 1.75 2,196 2.68 189 1.50 2,975 2.40 230 1.25 4,532 2.05 298 1.00 7,914 1.65 419 0.90 10,170 1.49 487 0.80 14,327 1.30 601 0.70 19,576 1.15 726 0.60 27,798 1.00 897 0.50 40,964 0.86 1,128 0.40 61,323 0.72 1,421 0.30 94,532 0.59 1,790 NOTES: (1) Resources constrained within a US$1,300/oz gold WhittleTM Pit Shell. Tonnage, grades and totals may not total due to rounding. The reported resources at a cutoff of 0.4 g/t is highlighted. Mineral resources that are not mineral reserves have no demonstrated economic viability and do not meet all relevant modifying factors. (2) The effective date of the mineral resource estimate is September 2019.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 188 14.4 Batman Estimation Quality Several methods were used to validate the block model to determine the adequacy of the Batman deposit resource. Confirmatory drilling was used to ascertain the general good quality of the model within the core zone. In addition, overlaid cumulative frequency plots of blocks, composites, and assays were used. The three overlaid plots showed the expected decrease in the variability of the gold distributions going from assays to assay composites and then to kriged blocks. In addition: „ Jackknife studies were employed to determine the optimum kriging search parameters and the overall quality of the estimation as required by classification. Figure 14-12 shows the Jackknife results for the measured class. „ Numerous swath plots were analyzed in the direction of rows and columns were used to verify that composite and block gold grades are spatially in sync. Several examples of these swath plots are shown in Figure 14-13. „ The use of visual inspection of the kriged blocks models in section and plan and the inspection of gold histograms of assays, composites and blocks.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 189 Figure 14-12: Jackknife Correlation Plot for Measured Blocks

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 190 Source: Tetra Tech, Inc (August 2019)- Figure 14-13: Jackknife Correlation Plot for Inferred Blocks

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 191 14.5 Modeling of the Quigleys Deposit The Quigleys Deposit is located approximately 3.5 km northeast of the Batman Deposit. The deposit is not as deep as the Batman deposit; it reaches a maximum depth of approximately 200 m. The deposit has been sampled with 57,600 m of drilling by 631 drillholes, with the majority reaching a depth of 100m at a 60 degree dip; oriented 83 degrees azimuth. Assays were taken at a nominal one meter interval. Geologic interpretation in section produced wireframes modeling thin ore zones dipping west. Material inside the wire frames was given a code of 1. Outside the mineralization zones, the material was given a code of 9999. Bulk density data were supplied by Pegasus for two ore types and waste within the oxide, transition and primary zones, based on a total of 39 samples collected from RC drilling. The two densities supplied were for stockwork and shear, with the density of the shear material substantially higher, particularly in the transition and primary zones. These samples were over one-m to two-m intervals and thus selected the narrow high grade portion of the shear zone as originally interpreted by Pegasus. The final mineralization envelope was much broader than this, and the bulk density was therefore estimated by assuming the final envelope contained 15% shear and 85% stockwork and weighting the density values accordingly. Table 14-7 shows the specific gravity data assigned to the Quigleys area according to oxidation state. Table 14-7: Quigleys Deposit Specific Gravity Data Oxide within modeled shear (t/cm) 2.60 Oxide Waste (t/cm) 2.62 Transition within modeled shear (t/cm) 2.65 Transition Waste (t/cm) 2.58 Primary within modeled shear (t/cm) 2.70 Primary Waste (t/cm) 2.61

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 192 14.5.1 Quigleys Exploration Database Table 14-8 summarizes the Quigleys exploration database. Table 14-8: Summary of Quigleys Exploration Database Drillhole Statistics Northing (m) AMG84 z53 Easting (m) AMG84 z53 Elevation (m) Azimuth Dip Depth (m) Minimum 8,430,1876 188,445.7 129.7 0 45 0 Maximum 8,432,290 189,746.5 209.0 354.0 90 330.5 Average 8,431,129.5 189,230.8 155.9 83.4 62.5 91.3 Range 2,104.0 1,300.8 79.3 354.0 45.0 330.5 Cumulative Drillhole Statistics Total Count 631 Total Length (m) 57,821 Assay Length (m) 1 (approx.) Drillhole Grade Statistics Number Average Std. Dev. Min. Max. Missing Au (g/t) 52,152 0.2445 0.8764 0 36.00 82 Cu (%) 40,437 0.0105 0.0305 0 2.98 11,897 14.5.2 Quigleys Block Model Parameters Quigleys’ block model parameters are shown in Table 14-9. The model consisted of 37,082 blocks within the modeled mineralized zones (blocks within the modeled grade zones are coded as 1). Each of the blocks is 250 m3 (5x25x2m) with a defined density of 2.77 g/cm (692.5 tonnes). Table 14-9: Block Model Physical Parameters – Quigleys Deposit Direction Minimum (m) AMG84 z53 Maximum (m) AMG84 z53 Block Size # Blocks x-dir 188,250 mE 189,900 mE 5m 330 y-dir 8,430,337.5 mN 8,432,487.5mN 25m 86 z-dir -200 m 208m 2m 204

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 193 Figure 14-14 shows the rock codes used for the Quigleys estimation. Source: Tetra Tech, Inc (August 2020) Figure 14-14: 3-D Visualization of the Quigleys Deposit Mineralized Zone Positions with Wireframe Codes The cap value of 12.0 g-Au/t has been chosen based on review of natural log transformed histograms, cumulative frequency and probability plots. Review of the log probability plot of the composited gold grades shows that there is a distinct break in the distribution at 12 g-Au/t. All gold composites were capped at this value. Two surfaces were generated based on historic downhole logging of drill holes. The first surface represents the boundary between weathered mineral type (oxide) and transition mineral type (mixed), and the second surface represents the boundary between transition mineral type and fresh mineral type (sulfide). Figure 14-15 shows the log (Au) variogram for along strike, down dip and down hole coded as AStrk, DDip, Dhole respectively. These variograms have a nugget of 0.77, with an ultimate sill of 2.74. The ranges are 90 meters Along Strike (AStrk) and 30 m Down Dip (DDip). Table 14-10 shows the search parameters selected for each domain.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 194 Source: Tetra Tech, Inc (August 2020) Figure 14-15: Quigleys Median Indicator Variogram

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 195 Table 14-10: Search Parameters for each Domain Code Azimuth Dip Axis1 m Axis2 m Axis3 m 0 280 35 90 90 30 1000 266 26 90 90 30 2000 273 35 90 90 30 3000 266 26 90 90 30 4000 273 35 90 90 30 5000 275 30 90 90 30 6100 280 35 90 90 30 6200 280 55 90 90 30 6300 280 70 90 90 30 7000 300 25 90 90 30 Table 14-11 lists the resource classification criteria. The classification was accomplished by a combination of search distance, kriging variance, number of points used in the estimate, and number of sectors used. The block model was estimated using ordinary kriging. The estimation searched for four composites in a sector, allowing a maximum of three composites per drillhole. Inside the ore zone (blocks coded as “1”); composites were selected only if they also were coded as “1”. Separate kriging passes were done at increasing search distances. The first pass and second pass restricted points to be within 30 m and 90 m as defined by the search ellipsoid axis to produce provisional resources classes of measured and indicated. Review of the kriging error plotted as a log-probability graph indicated that the gold estimates were particularly poor when kriging variances were greater than 1.0 and 1.55 for the measured and indicated classes respectively. Hence the provisional Measured, Indicated, inferred (MIF) codes were then adjusted to a more restricted class when a blocks kriging error exceeded this value. Table 14-11: Search Parameters and Sample Restrictions Domain Class Drill Holes Max Sample Per Drill Hole Search Major Search Semi- major Search Minor Kriging Error 1000 to 7000 Measured >= 3 4 30 30 10 <=1.00 1000 to 7000 Indicated >=2 4 90 90 30 <=1.55 1000 to 7000 inferred >=1 4 90 90 30 NA 0 inferred >=2 2 30 30 10 NA For the outside zone, a two-stage kriging for MIF class 3 was done inside and outside of modelled wireframes with a maximum search ellipse range of 90 m and 30 m respectively. Each domain was assigned a unique search orientation; however, kriging parameters were the same for all domains. Blocks with a given domain code were estimated only by composites of the same code.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 196 Several methods used to validate the block model were used to determine the adequacy of the Quigleys resource. Cumulative frequency plots of blocks, composites, and assays were overlaid. The three overlaid plots showed the expected decrease in the variability of the gold distributions going from assay to assay composites and then to kriged blocks. Additional verification of the block model was completed by the use of jackknife studies (model validation) where known assays were estimated using surrounding samples, visual inspection of the kriged blocks models in section and plan and the inspection of gold histograms of assays, composites and blocks. Table 14-12 lists the parameters used to generate a pit shell using Geovia’s WhittleTM software (version 4.7) for reporting the measured plus indicated resource in Table 14-13 and the inferred resource in Table 14-14. Note that these parameters are not the same as those specified for the Batman deposit. Quigleys has geologic, metallurgical and mining cost characteristics that require its own parameter specifications. For example, the differing orientation of the mineralized zones between Batman and Quigleys (Batman is steeply dipping, while Quigleys is shallower) impact mining costs, as well as the location of the Quigleys deposit requiring greater haulage than for Batman. The Quigleys deposit is also anticipated to be mined with smaller equipment resulting in a loss of economics of scale. In addition, the costs are better known for Batman and can be stated with more certainty, while the costs for Quigley’s are not as well-known and therefore more conservative costs were used. These parameters used to constrain a resource provide simply a reasonable potential extraction for the commodity being estimated. Mineral resources that are not mineral reserves have no demonstrated economic viability and do not meet all relevant modifying factors. Table 14-12: WhittleTM Pit Shell Parameters for the Quigleys Deposit Item Input Gold Price US$1,300 per troy ounce Gold Recovery 82% Sulfide 78% Transition 78% Oxide Payable Gold 99.90% Overall Mining Cost US$1.90 per tonne Processing Cost US$9.779 per tonne processed Tailings US$0.985 per tonne processed Water Treatment US$0.09 per tonne processed Royalty 1% NPR Sell Cost US$3.19 Table 14-13: Estimated Resources Measured and Indicated Classes for the Quigleys Deposit, All Mineral Types Resource Class Cutoff Tonnage (000) Grade Au g/t Ounces Au (000) Measured & Indicated 0.3 8128 1.09 285 Measured & Indicated 0.4 7895 1.11 282 Measured & Indicated 0.5 7211 1.17 272 Measured & Indicated 0.6 6234 1.27 255 Measured & Indicated 0.7 5207 1.39 233

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 197 Resource Class Cutoff Tonnage (000) Grade Au g/t Ounces Au (000) Measured & Indicated 0.8 4288 1.53 211 Measured & Indicated 0.9 3533 1.68 191 Measured & Indicated 1 2944 1.83 173 Measured & Indicated 1.25 1987 2.17 139 Measured & Indicated 1.5 1457 2.46 115 Measured & Indicated 1.75 1065 2.77 95 Measured & Indicated 2 826 3.03 81 NOTE: (1) Resources constrained within a US$1,300/oz gold WhittleTM Pit Shell; Tonnage, grades and totals may not total due to rounding and show the reported resources at the chosen cutoff of 0.4 g/t? (2 The effective date of the mineral resource estimate is September 2019. Source: Tetra Tech, Inc. (August 2020) Figure 14-16: Grade Tonnage Curve Estimated Resources Measured and Indicated Class, All Mineral Types for the Quigleys Deposit

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 198 Table 14-14: Estimated Resource Inferred Class for the Quigleys Deposit, Resource Class Cutoff Tonnage (000) Grade Au g/t Ounces Au (000) Inferred 0.3 4057.10 1.44 188 Inferred 0.4 3980.65 1.46 187 Inferred 0.5 3671.75 1.55 182 Inferred 0.6 3284.60 1.66 176 Inferred 0.7 2832.35 1.82 166 Inferred 0.8 2466.84 1.98 157 Inferred 0.9 2161.41 2.14 149 Inferred 1 1982.68 2.25 144 Inferred 1.25 1532.17 2.59 127 Inferred 1.5 1195.76 2.93 113 Inferred 1.75 842.78 3.47 94 Inferred 2 642.34 3.98 82 NOTE: (1) The effective date of the mineral resource estimate is September 2019. 14.6 Existing Heap Leach Gold Resource In addition to the in-situ gold resource for the Batman Deposit, a historical heap leach pad (HLP) adjacent to the current Mt Todd pit was analyzed for gold. The HLP is a remnant of the Pegasus operation, pre-2006. The HLP’s geometry was analyzed using historical maps to determine the pile bottom and current surveys of the present day surface. This work produced two surfaces which were used to calculate the volume of the pile. The concentration of gold was analyzed with 24 vertical drillholes separated by an approximately 100 meters. Drilling depth was terminated 5-meters before the final depth of the heap to keep from piercing the bottom liner. The 363 assays from 1-m composites were analyzed for gold and copper grade. Density of the pile was estimated from 11 drillholes using 1,162 dual density sidewall gamma probe technology. Note that the probe uses a gamma source and a scintillation detector to estimate density via the Compton Effect. A nearest neighbor (polygon) method was employed to estimate grades within the heap leach pad since there is no apparent spatial correlation between samples. The existing heap leach pad is estimated to contain 230,000 ounces of gold within 13.4 Mt of indicated mineral resource at an average grade of 0.54 g-Au/t. It is the opinion of the QP [Rex Clair Bryan, Ph.D., SME RM] that the heap leach resource can be classified as an indicated mineral resource as the surveyed volume, the tonnage derived from density measurements, and grade assays from drillhole sampling reconciles with Pegasus’ original reported values. Table 14-15 lists the indicated mineral resources for the existing heap leach pad. Note the grade-tonnage plot in Figure 14-17. The majority of tonnage has an average grade of 0.5 g-Au/t as indicated by the flat portion of the tonnage curve. Note too that no cutoff grade was applied to the heap leach pad resource as all material will be processed as part of the site rehabilitation process. Copper was also estimated, but the copper results are not presented here.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 199 Table 14-15: Existing Heap Leach Indicated Gold Resource Estimate (September 2019) Cutoff Grade g-Au/t Tonnes (000s) Average Grade g-Au/t Total Au Ounces (000s) INDICATED 0 13,400 0.541 230 NOTE: (2) No cutoff grade is technically applied as all heap leach material will be re-processed. (3) Resources are reported at 0.4 g/t cutoff gold grade to be consistent with the reported Batman and Quigleys resource. (4) Resource is defined by the geometry of the existing heap leach pad. (5) Resource & reserve estimates for the heap leach materials are the same because 100% of the heap leach material is processed at the conclusion of mining the Batman Pit. (6) The effective date of the mineral resource estimate is September 2019. Source: Tetra Tech, Inc (August 2020) NOTE: Mineral resources that are not mineral reserves have no demonstrated economic viability and do not meet all relevant modifying factors. Figure 14-17: Inferred Resource Grade Tonnage Curve for the Quigleys Deposit

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 200 14.7 Relevant Factors Affecting Resource Estimates Different mining and metallurgical parameters are used for the Batman and Quigleys deposits. These parameters are used to produce a mining geometry that provides a reasonable prospect of economic viability. The different set of parameters reflects that each deposit is unique in geology and location. The Batman mining and milling costs and other technical parameters are better known and can be stated with more certainty than for Quigleys, whereas the technical parameters and costs for Quigleys are not as well-known and therefore more conservative costs were used. In addition, physical factors also impact these technical parameters. For example haulage from the Quigleys deposit to the plant is farther than for Batman and the dumping space has not been fully determined, so additional haulage is anticipated for Quigleys. In addition, the Quigleys deposit is anticipated to be mined with smaller equipment resulting in a loss of economics of scale. It is the opinion of the QP that there are currently no known environmental, permitting, legal, title, taxation, socio-economic, marketing, political or other relevant factors which could affect the mineral resource estimate.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 201 15.0 MINERAL RESERVES The measured and indicated resource estimates presented in Section 14 were used to estimate reserves. Reserve definition is done by first identifying ultimate pit limits using economic parameters and pit optimization techniques. The resulting optimized pit shells were then used for guidance in pit design to allow access for equipment and personnel. Several phases of mining were defined to enhance the economics of the project, and the QP [Thomas L. Dyer, P.E.] used the phased pit designs to define the production schedule to be used for cash-flow analysis for the preliminary feasibility study. The following section details the definition of reserves used for the production scheduling. Later sections detail the production schedule and the mining costs used in the cash-flow model. 15.1 Pit Optimization Pit optimization was done using Geovia’s WhittleTM software (version 4.7) to define pit limits with input for economic and slope parameters. The optimization used parameters provided by Vista and their consultants based on current and previous studies. Optimization used only measured and indicated material for processing. All inferred material was considered as waste. Varying gold prices were used to evaluate the sensitivity of the deposit to the price of gold, as well as to develop a strategy for optimizing project cash flow. To achieve cash-flow optimization, mining phases or push backs were developed using the guidance of WhittleTM pit shells at lower gold prices. 15.1.1 Economic Parameters Initially, several iterations of pit optimizations were reviewed for the final determination of pit limits based on the prefeasibility parameters. Initial mining cost parameters were based on the economic parameters provided in Table 15-1. The final mining costs from this study have turned out to be lower than those in Table 15-1 and the recoveries were higher, thus making the pit optimization conservative with respect to costs and resulting reserves. Table 15-1: Initial Economic Parameters Parameter Value Used Gold Recovery 85% Sulfide 80% Transition 80% Oxide Payable Gold 99.9% Overall Mining Cost US$1.90 per tonne Processing Cost US$7.80 per tonne processed Tailings US$0.90 per tonne processed General & Administrative $0.46 per tonne processed Water Treatment US$0.10 per tonne processed JAAC Royalty 1% gross proceeds

.normal width the east side, or bolt and mesh the high wall. In both cases the ramp along the wall would be reduced to a The primary change suggested by Call & Nicholas (2016) is to either place catch benches in the high wall on that would slough off of the wall. roads on the east side were widened to allow a berm to be maintained along the road to contain any rock on the east side of the pit and that these catch benches should not be placed in the design. For safety, the & Nicholas, Inc. (2016). The Golder parameters suggested that the catch benches would not be maintainable Support of the Definitive Feasibility Study”). Minor modifications were made based on comments from Call Golder memo dated September 13, 2011 (“Mt Todd Gold Project: Batman Pit Slope Design Guidance in The slope parameters were based on studies provided by Golder Associates and Ken Rippere as detailed in a 15.1.2 Slope Parameters the processing cost and recovery adjustments. grade and selection of pit limits using a lower gold price pit shell create additional conservatism that offset Final mining and process operating costs are somewhat higher; however, the imposition of an elevated cutoff ~91% for transition material, and ~90% for oxide material. The use of the constant tails resulted in higher final back calculated recoveries of ~92% for sulfide material, „ 1.50 and above = 0.13 g Au/t tail „ 1.00 to 1.50 = 0.10 g Au/t tail „ 0.80 to 1.00 = 0.08 g Au/t tail „ 0.60 to 0.80 = 0.06 g Au/t tail „ 0.40 to 0.60 = 0.05 g Au/t tail „ 0.20 to 0.40 = 0.04 g Au/t tail The ranges for the constant tail, based on model grade input in g Au/t are: ݑ௚௥௔ௗ௘ܣ ݐ . ݈ܶܽ݅௚௥௔ௗ௘ݏ݋݊ܥݑ௚௥௔ௗ௘ െܣ :equation used to calculate the recovery based on the constant tail is Final recoveries were estimated using a constant tail by range of grades for the processed material. The determine different optimized pit shells. various gold prices from US$300 to US$2,000 per ounce, in increments of US$20 per ounce, were used to A base gold price of US$1,250 per ounce was determined by the QP for use in scenario analysis. However, maintain higher grades with respect to material to be processed and is appropriate for the reserves. request, The QP [Thomas L. Dyer, P.E.] used a minimum cutoff grade of 0.40 g-Au/t. This was done to their consultants. The calculated cutoff grade based on the economic parameters is 0.33 g-Au/t. At Vista’s Processing, tailings construction, tailings reclamation, and water treatment costs were provided by Vista and US$1.64/tonne. The total mining cost (reference plus incremental) is US$1.90. capacity. The reference mining cost was determined using first principles. Reference mining costs of truck operating costs, truck cycle time to haul and return through a six-meter gain in elevation, and truck for both waste and ore for each bench that is to be mined. The incremental cost was determined based on 6-meter bench below the 145-meter elevation. This represents the incremental increase in cost of haulage The mining costs used were varied by bench. An incremental cost of US$0.010/tonne was added for each Tetra Tech October 2019 202 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project NI 43-101 Technical Report Vista Gold Corp.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 203 The QP [Thomas L. Dyer, P.E.] has reviewed the geotechnical reports prepared by Golder Associates and Mr. Rippere, and the subsequent comments from Call and Nicholas, Inc. (2016) and has determined that the recommended pit-slope parameters derived from these reports and subsequent comments are appropriate for use in the Amended Technical Report. For this study, catch benches were inserted in preliminary pit phases. However, the ultimate pit used a flat slope with bolting and mesh. This helps to improve the overall slope and the reduce the resulting stripping. Figure 15-1. Each sector was modeled into a zone resulting in eight zones. Slopes on the eastern side of the pit were reduced to account for ramps in the high wall. The recommended and adjusted inner-ramp angles are shown in Table 15-2. Table 15-2: Slope Angles for Pit Optimization Zone Sector Slope Angle (°) Adjusted Angle (°) 1 Northeast 36 33 2 East 40 36 3 South 55 50 4 Southwest 55 55 5 Northwest 51 51 6 Northeast & East Weathered 33 33 7 South & Southwest Weathered 45 45 8 Northwest - Weathered 45 45

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 204 Source: Golder Associates, 2011 Figure 15-1: Mt Todd Geotechnical Sectors 15.1.3 Pit-Optimization Results WhittleTM pit optimizations were run using the economic and slope parameters described in previous sections. Pit optimizations were completed using prices of US$300 to US$2,000 per ounce gold with increments of US$20 per ounce. One additional pit shell was created using US$1,250 per ounce gold price. These pits were used to assess the deposit’s sensitivity to gold prices for both scenarios. Results for US$100 per ounce increments, from US$300 to US$2,000 per ounce of gold, are shown in Table 15-3, with a highlighted price of US$1,000/oz-Au as the pit shell used to guide the ultimate pit design. The pit optimizations only used measured and indicated resources. Inferred materials are considered waste.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 205 Graphs of the tonnes and contained ounces from the WhittleTM results are shown in Figure 15-3. Table 15-3: WhittleTM Pit Optimization Results –using 0.40 g-Au/t Cutoff Pit Gold Price (US$) Material Processed Waste Tonnes Total Tonnes Strip Ratio K Tonnes g-Au/t K Ozs Au 1 $ 300 3,282 1.77 186 2,797 6,078 0.85 6 $ 400 8,578 1.54 425 7,507 16,085 0.88 11 $ 500 15,988 1.34 686 15,740 31,728 0.98 16 $ 600 37,253 1.12 1,340 53,757 91,010 1.44 21 $ 700 89,301 0.99 2,855 171,617 260,918 1.92 26 $ 800 121,187 0.92 3,585 222,919 344,106 1.84 31 $ 900 159,485 0.87 4,442 316,889 476,374 1.99 36 $ 1,000 185,915 0.85 5,093 429,208 615,123 2.31 41 $ 1,100 212,340 0.84 5,741 566,907 779,247 2.67 46 $ 1,200 230,587 0.83 6,184 675,714 906,302 2.93 49 $ 1,250 234,858 0.83 6,278 700,519 935,376 2.98 51 $ 1,300 240,195 0.83 6,416 742,833 983,029 3.09 56 $ 1,400 243,306 0.83 6,498 771,190 1,014,497 3.17 61 $ 1,500 249,389 0.83 6,658 829,933 1,079,321 3.33 66 $ 1,600 254,050 0.83 6,779 880,583 1,134,633 3.47 70 $ 1,700 254,348 0.83 6,785 883,222 1,137,571 3.47 74 $ 1,800 259,140 0.83 6,908 943,012 1,202,152 3.64 78 $ 1,900 259,964 0.83 6,927 952,872 1,212,836 3.67 81 $ 2,000 260,099 0.83 6,929 953,985 1,214,083 3.67 Pit 36 was used for design purposes.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 206 NI 43-101 Technical Report – Mt Todd Gold Project 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia – May 29, 2013 Figure 15-2: Measured and Indicated Graph of WhittleTM Results –0.40 g-Au/t Minimum Grade 15.1.4 Ultimate Pit Limit Selection The ultimate pit limit was determined by the QP responsible for this section based on various iterations analyzed by MDA, Vista, and Tetra Tech. A lower gold price pit shell was used as a guide for the ultimate pit design. This decision was made to reduce the project footprint while still capturing the most valuable material in the pit optimizations. For consistency, pit shells that closely replicate the tonnage from the previous NI 43-101 Technical Report (Tetra Tech, 2014) were selected for guidance in pit design. The QP [Thomas L. Dyer, P.E.] selected US$1,000 and US$1,020 gold pit shells for the ultimate pit design. 15.2 Pit Designs Detailed pit designs were completed, including an ultimate pit and three internal pits. The ultimate pits were designed to allow mining economic resources identified by WhittleTM pit optimization, while providing safe access for people and equipment. Internal pits or phases within the ultimate pits were designed to enhance the project by providing higher-value material to the processing plant earlier in the mine life. 15.2.1 Bench Height Pit designs used six-meter benches for mining. This corresponds to the resource model block heights, and the QP for this section believes this to be reasonable with respect to dilution and equipment anticipated to be used in mining. In areas where the material is consistently ore or waste, so that dilution is not an issue, benches may be mined in 12-meter heights.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 207 15.2.2 Pit Design Slopes The QP responsible for this section based the slope parameters on geotechnical studies by Golder Associates and Ken Rippere (Golder, 2011) as reviewed by Ross Barkley of Call & Nicholas (Barkley, 2016). . The largest difference between the previous and 2017 slopes is in the use of catch benches on the eastern walls. The previous parameters specified the use of a flat wall on the east without any catch benches. To keep rocks from rolling down on trucks, the ramps were designed to be 28 m wide (total width of 50 m), so that a berm could be placed and rock would collect at the base of the slope behind the berm. Call & Nicholas (2016) commented that “for interim phases, assuming a 47- to 50-degree bedding dip the interramp angles should be 37- to 39-degrees in order to maintain a 9+ meter wide catch bench”. For the final walls in the northeast area, the recommendations continue to state “… the walls will be smooth and excavated to the bedding dip” and “To mitigate the rock fall risk in the final wall, it is recommended that mesh be installed over the interramp slopes between the ramps.” The recommended slopes are developed around five different sectors in fresh rock and three sectors in weathered rock as shown in Table 15-4. The design parameters used are shown in Table 15-4 for the ultimate pit and Table 15-5 shows the sector 1 and 2 slope parameters for interim pit designs. The parameters are applied based on height between catch benches in meters (BH), safety berm widths in meters (berms), bench face angles in degrees (BFA) and inner-ramp angles also in degrees (IRA). Table 15-4: Pit Design Slope Parameters Due North Sector 1 Sector 2 Sectors 3 & 4 Sector 5 Sector 6 Sector 7 Sector 8 BH (m) 24 24 24 24 24 30 30 30 BFA (°) 61 47 49 73 68 35 60 60 Berm (m) 9.5 - - 9.5 9.5 12.0 12.0 12.0 Net IRA (°) 46.5 47.0 49.0 54.9 51.3 28.7 45.7 45.7 In the northern direction the slope azimuth must be 205 degrees or better. Table 15-5: Interim Pit Slope Parameters (Sectors 1 & 2) Northeast East BH (m) 24 24 BFA (*) 48 49 Berm (m) 9.5 9.5 Net IRA (*) 37.6 38.3 Zone 1 2 For design purposes, weathered material is considered to be the top 30 meters from the surface.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 208 15.2.3 Haulage Roads Ramps were designed to have a maximum centerline gradient of 10%. In areas where the ramps may curve along the outside of the pit, the inside gradient may be up to 11% or 12% for short distances. Designs use switchbacks to maintain the ramp system on the east side of the pit. This is done to better match the dip of the deposit and also allows better traffic connectivity between pit phases. In areas where switchbacks are employed, a maximum centerline gradient of 8% is used. Ramp width was determined as a function of the largest haul truck width to be used. Mine plans use 226-tonne capacity trucks with operating widths of 8.30 meters. For haul roads inside of the pit, a single safety berm on the inside of the roadway will be required to be at least half the height of the largest vehicle tire that uses the road. MDA has designed safety berms with a 1.5 horizontal to 1 vertical slope using run-of- mine material, and a height of 1.97 meters, which provides half of the truck tire height plus 10% for the haul trucks. The 10% addition is used to ensure that the berm height exceeds half of the truck tire height in all cases. The resulting base width of safety berms is 5.9 meters. Haul-roads inside of the pit, where only one safety berm is required, are designed to be 32 meters wide for two-way traffic. Subtracting berm widths, this provides 3.14 times the width of haul trucks for running width. In lower portions of the pit, where haulage requirements allow use of one-way traffic, haul roads are designed to have a width of 20 meters. This provides 1.7 times the width of haul trucks for running width. Haul roads outside of pit designs have been designed to be 42 meters wide to account for an additional safety berm. 15.2.4 Ultimate Pit The final ultimate pit design uses switchbacks to maintain the ramp system on the east side of the pit. This allows for better traffic flow between pit phases and allows the west side of the pit to best follow the dip of the deposit. In all, there are four switchbacks in the ultimate pit design and the lower portions of the pit have spirals to achieve the ultimate pit design. The ultimate pit design, along with the ultimate dump and stockpile designs, and planned infrastructure, are shown in Figure 15-3.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 209 Figure 15-3: Mt Todd Ultimate Pit Design – (October 4, 2019)

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 210 15.2.5 Pit Phasing Phase 1 continues the western wall down from that done by prior operators and wraps the ramp around the pit clockwise from the south. Phase 2 expands the pit to the east, north, and south, maintaining a portion of the phase 1 west wall. The phase 2 ramp is placed on the east wall and has a total of five switchbacks located in the north and south ends of the pit. Phase 3 will be mined to the final wall on the western side of the pit. Phase 4 expands the pit to the north, east, and south and mines under the phase 3 pit to the ultimate pit limits. The first three phases, prior to the ultimate pit, are presented in Figure 15-4 to Figure 15-6.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 211 Figure 15-4: Phase 1 Design (February 12, 2018)

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 212 Figure 15-5: Phase 2 Design (February 12, 2018)

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 213 Figure 15-6: Phase 3 Design (February 12, 2018) MINE DEVELOPMENT ASSOCIATES 9-Feb-2018 Scale: Northern Territory, Australia Mt Todd Gold Project Vista Gold as shown meter 0250500 Plan Map showing Base Case Phase 3 Design -215 -112

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 214 15.3 Cutoff Grade The breakeven and internal cutoff grades calculated using the economic parameters are shown in Table 15-6. The internal cutoff grade assumes that mining is constrained to an economic pit and does not include the mining cost. To enhance projects economics, Vista has decided to use an elevated cutoff grade for reserves and scheduling. Reserves are reported using 0.40 g-Au/t cutoff grade. A cutoff grade of 0.40 g Au/t is equivalent to using $1,000 per ounce Au internal cutoff grade for sulfide material and a $1,100 per ounce Au internal cutoff grade for transition and oxide material. As the cutoff grade is higher than the cutoff grades using the $1,250 per ounce gold price, the statement of reserves with the elevated cutoff grade are reasonable. Table 15-6: US$1,250 Gold Price Cutoff Grades (g-Au/t) Prefeasibility Scenario Sulfide Transition Oxide Breakeven 0.33 0.35 0.35 Internal 0.28 0.29 0.29 Cutoff Grade Used 0.40 0.40 0.40 For purposes of production scheduling, low-grade, medium-grade, and high-grade material was designated. The low-grade material used the reserve cutoff grade (0.40 g-Au/t). Medium-grade and high-grade cutoffs used were 0.55 and 0.85 g-Au/t, respectively. 15.4 Dilution The resource block model was estimated with block sizes of 12m by 12m by 6m, and this model was used to define the ultimate pit limit, and to estimate proven and probable reserves. The QP responsible for this section considers the 12m by 12m by 6m block size to be reasonable for open pit mining of the deposit and believes that this represents an appropriate amount of dilution for statement of reserves. 15.5 Reserves Mineral reserves for the project were developed by applying relevant economic criteria (modifying factors) in order to define the economically extractable portions of the estimated resources. The QP [Thomas L. Dyer, P.E.] developed the reserves to be in accordance with NI 43-101, which is based on the CIM Standards. CIM Standards define modifying factors as: Modifying factors are considerations used to convert mineral resources to mineral reserves. These include, but are not restricted to, mining, processing, metallurgical, infrastructure, economic, marketing, legal, environmental, social and governmental factors. CIM Standards define mineral reserves as: Mineral reserves are sub-divided in order of increasing confidence into probable mineral reserves and proven mineral reserves. A probable mineral reserve has a lower level of confidence than a proven mineral reserve.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 215 A mineral reserve is the economically mineable part of a measured and/or indicated mineral resource. It includes diluting materials and allowances for losses, which may occur when the material is mined or extracted and is defined by studies at pre-feasibility or feasibility level as appropriate that include application of modifying factors. Such studies demonstrate that, at the time of reporting, extraction could reasonably be justified. The reference point at which mineral reserves are defined, usually the point where the ore is delivered to the processing plant, must be stated. It is important that, in all situations where the reference point is different, such as for a saleable product, a clarifying statement is included to ensure that the reader is fully informed as to what is being reported. The public disclosure of a mineral reserve must be demonstrated by a pre-feasibility study or feasibility study. Mineral reserves are those parts of mineral resources which, after the application of all mining factors, result in an estimated tonnage and grade which, in the opinion of the QP(s) making the estimates, is the basis of an economically viable project after taking account of all relevant modifying factors. Mineral reserves are inclusive of diluting material that will be mined in conjunction with the mineral reserves and delivered to the treatment plant or equivalent facility. The term ‘mineral reserve’ need not necessarily signify that extraction facilities are in place or operative or that all governmental approvals have been received. It does signify that there are reasonable expectations of such approvals. ‘Reference point’ refers to the mining or process point at which the QP prepares a mineral reserve. For example, most metal deposits disclose mineral reserves with a “mill feed” reference point. In these cases, reserves are reported as mined ore delivered to the plant and do not include reductions attributed to anticipated plant losses. The QP must clearly state the ‘reference point’ used in the mineral reserve estimate. Probable Mineral Reserve A probable mineral reserve is the economically mineable part of an indicated, and in some circumstances, a measured mineral resource. The confidence in the modifying factors applying to a probable mineral reserve is lower than that applying to a proven mineral reserve. The QP(s) may elect, to convert measured mineral resources to probable mineral reserves if the confidence in the modifying factors is lower than that applied to a proven mineral reserve. Probable mineral reserve estimates must be demonstrated to be economic, at the time of reporting, by at least a Pre-Feasibility Study. Proven Mineral Reserve A proven mineral reserve is the economically mineable part of a measured mineral resource. A proven mineral reserve implies a high degree of confidence in the modifying factors. Application of the proven mineral reserve category implies that the QP has the highest degree of confidence in the estimate with the consequent expectation in the minds of the readers of the report. The term should be restricted to that part of the deposit where production planning is taking place and for which any variation in the estimate would not significantly affect the potential economic viability of the deposit. Proven mineral reserve estimates must be demonstrated to be economic, at the time of reporting, by at least a pre-feasibility study. Within the CIM Definition standards the term proved mineral reserve is an equivalent term to a proven mineral reserve.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 216 Proven and probable reserves are stated based on the prefeasibility study pit designs. Table 15-7 reports the proven and probable reserves, by pit phase, along with waste material for the pit designs discussed in previous sections. The QP [Deepak Malhotra, Ph.D., SME RM] is responsible for reporting of the heap-leach pad reserves (Section 15.6 – Heap Leach Reserve). This is based on the tonnage and grade of heap-leach material that was loaded onto a heap-leach pad by a historical operator. The tonnes and grades are well known based on record keeping of the historical operator as discussed in Section 14.0 – Mineral Resource Estimate. The heap-leach reserves are shown with the Batman reserves in Table 15-8. Reserves are shown to be economically viable based on cash flow analysis provided by the QP [Jessica I. Monasterio, P.E.]. The QP responsible for this section [Thomas L. Dyer, P.E.] has reviewed the cash flow and believes that they are reasonable for the statement of proven and probable reserves. Table 15-7: In-Pit Proven and Probable Reserves by Pit Phase Proven Probable Total P&P Waste Total Strip K Tonnes g Au/t K Ozs Au K Tonnes g Au/t K Ozs Au K Tonnes g- Au/t K Ozs Au K Tonnes K Tonnes Ratio Ph_1 13,551 1.09 473 6,245 1.10 221 19,796 1.09 694 19,312 39,109 0.98 Ph_2 18,980 0.80 490 19,008 0.88 538 37,988 0.84 1,028 59,167 97,155 1.56 Ph_3 20,356 0.87 571 27,471 0.85 747 47,827 0.86 1,318 122,372 170,198 2.56 Ph_4 19,785 0.82 523 82,291 0.78 2,052 102,076 0.78 2,576 322,138 424,215 3.16 Total 72,672 0.88 2,057 135,015 0.82 3,559 207,687 0.84 5,616 522,990 730,677 2.52 NOTES: (1) Proven and probable mineral reserves are reported using a cutoff grade of 0.40 g-Au/t. (2) The reserves point of reference is the point where material is fed into the mill. (3) The effective date of the mineral reserve estimates is September 2019. Table 15-8: Total Batman Project Reserves (Including Heap Leach) Batman Deposit Heap Leach Pad Total P&P Reserves Tonnes (000s) Grade (g/t) Contained Ounces (000s) Tonnes (000s) Grade (g/t) Contained Ounces (000s) Tonnes (000s) Grade (g/t) Contained Ounces (000s) Proven 72,672 0.88 2,057 - - - 72,672 0.88 2,057 Probable 135,015 0.82 3,559 13,354 0.54 232 148,369 0.79 3,791 Proven & Probable 207,687 0.84 5,616 13,354 0.54 232 221,041 0.82 5,848 NOTES: (4) Thomas L. Dyer, P.E., is the QP responsible for reporting the Batman deposit proven and probable reserves. (5) Batman deposit reserves are reported using a 0.40 g-Au/t cutoff grade. (6) Deepak Malhotra is the QP responsible for reporting the heap-leach pad reserves. (7) Because all of the heap-leach pad reserves are to be fed through the mill, these reserves are reported without a cutoff grade applied. (8) The reserves point of reference is the point where material is fed into the mill. (9) The effective date of the mineral reserve estimates is September 2019.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 217 15.6 Heap Leach Reserve Estimate Heap leach reserves are provided in Table 15-8. In addition to the ore mined from the Batman open pit, the mine plan contemplates processing the 13.4 Mt of ore from the existing heap leach pad through the mill at the end of the mine life. The bottle roll and column leach test work undertaken at the ALS Metallurgy Laboratory in Australia has been reviewed (ALS, 2013). The testwork indicated the following: „ Cyanidation leach tests on “as is” material on the heap will extract ± 30% of the gold. „ CIP cyanidation tests at a grind size of P80 of 90 microns will extract on average 72% of gold (range: 64.14% to 80.37%) in 24 hours of leach time. The average lime and cyanide consumptions were 1.75 kg/t and 0.78 kg/t, respectively. The limited testwork indicates that it is economically feasible to process and recover gold from the heap leach material. Hence, the 13.4 Mt of heap leach ore meets the criteria necessary to be called “reserves” for the Mt Todd Gold Project and should be included in the reserve tabulation based on the following: „ The heap leach material is already mined; „ The contained gold is readily recoverable using the planned flowsheet; and „ The heap leach material can be economically processed in the plant which will be built to process fresh ore. These reserves should be considered as probable since limited drilling and assaying was undertaken to estimate the gold content of the heap leach residues.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 218 16.0 MINING METHODS This section is based on 50,000 tpd operation. 16.1 Methods The Project has been planned as an open-pit truck and shovel operation. The truck and shovel method provides reasonable cost benefits and selectivity for this type of deposit. Only open-pit mining methods are considered for mining at Mt Todd. The mining method and approach are based on the geotechnical and hydrological data and studies described in Sections 15.1.2 – Slope Parameters, Section 15.2.2 – Pit Design Slopes, and Section 24.5– Regional Groundwater Model and Mine Dewatering. 16.2 Site Landforms and Impoundments For reference, a description of the site landforms and impoundments, as well as their naming conventions and abbreviations is included as Table 16-1. Table 16-1: Description of Landforms and Impoundments Landform/Impoundment Abbreviated Name Tailings Storage Facility 1 TSF 1 Tailings Storage Facility 2 TSF 2 Raw Water Dam RWD Low Grade Ore Stockpile LGOS Low Grade Ore Stockpile Retention Pond LGRP Heap Leach Pad HLP Batman Pit RP3 Process Plant Retention Pond PRP Waste Rock Dump WRD Waste Rock Dump Retention Pond RP1 Process Water Pond PWP Water Treatment Plant WTP Process Plant PP

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 219 16.3 Waste Material Definition Some of the waste material at Mt Todd contains sulfide minerals, which can result in acid generation. Tetra Tech provided MDA with classification criteria for waste material so that the resulting production schedule can include the segregation of waste types for proper handling. Waste was classified into three classes based on total sulfur content as follows: „ Non-PAG Total Sulfur <= 0.25% „ Uncertain Total Sulfur > 0.25% and <= 0.40% „ PAG Total Sulfur > 0.40% Material classified as uncertain or potentially acid generating (PAG) material was scheduled so that it could be placed inside of the ultimate waste dump. Non-potentially acid generating material (Non-PAG) was scheduled to be used to encapsulate the uncertain and PAG material, and for reclamation cover and construction material for TSF 1 and TSF 2. Due to the scheduled timing of mining of Non-PAG material, some of this material will be stockpiled on the outer portions of the waste dump and re-handled as required. 16.4 Mine-Waste Facilities Total contained waste tonnage is 523 million tonnes. For both cases, Non-PAG mine waste will be used for construction and final reclamation cover on the mine site. The construction material will be used at the tailings storage facilities (“TSF 1” and “TSF 2”). Other Non- PAG material will be used for reclamation purposes covering tailings and other facilities at the end of the mine life. Sorter tailings will be generated from the process plant sorter and either used for ongoing construction uses or hauled to a temporary stockpile near the sorter. This material is considered Non-PAG and will be re- handled at the end of the mine life as part of the reclamation material. Tetra Tech provided the amount of material that would be required to be mined for construction and reclamation. These totals are shown in Table 16-2.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 220 Table 16-2: Construction and Reclamation Requirements Units Yr -1 Yr 1 Yr 2 Yr 3 Yr 4 Yr 5 Yr 6 Yr 7 Yr 8 Yr 9 Yr 10 Yr 11 Yr 12 Yr 13 Yr 14 Total CONSTRUCTION MATERIAL REQUIREMENTS Total TSF 1 K m^3 675 625 - - 210 - 219 222 - - 235 235 367 - - 2,787 K Tonnes 1,350 1,250 - - 420 - 438 443 - - 470 470 734 - - 5,575 Total TSF 2 K m^3 - - 3,381 2,902 1,878 1,348 1,919 1,387 3,296 - 2,935 2,904 218 - - 22,169 K Tonnes - - 6,763 5,804 3,757 2,697 3,837 2,774 6,592 - 5,869 5,808 437 - - 44,337 Total - All TSFs K m^3 675 625 3,381 2,902 2,088 1,348 2,137 1,609 3,296 - 3,169 3,139 586 - - 24,956 K Tonnes 1,350 1,250 6,763 5,804 4,176 2,697 4,275 3,218 6,592 - 6,339 6,278 1,171 - - 49,912 RECLAMATION MATERIAL REQUIREMENTS Sorter Reject to TSF 1 10,771 10,771 Sorter Reject to TSF 2 9,997 9,997 Total Sorter Reject Re-handle - - - - - - - - - - - - - - 20,769 20,769 TSF 1_Closure - - - - - - - - - - - - - 135 3,750 3,885 TSF 2_Closure - - - - - - - - - - - - - 664 3,506 4,170 Total Non-PAG - - - - - - - - - - - - - 799 48,793 49,593

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 221 The mine waste facility has been designed to permanently contain the remaining waste material associated with reserves in the pits for both cases. This facility is an extension of the existing waste dump at site with the ultimate dump fully encapsulating the current dump. The ultimate design incorporates an angle of repose slope of 1.5 vertical to 1.0 horizontal, with catch benches of 8.0 meters every 30 meters in height. During the construction of the ultimate dump, PAG and uncertain waste materials will be dumped in the interior of each lift of the waste dump. Non-PAG material will be dumped to the outer edge of each lift. It is anticipated that at least a 10 meter rind of Non-PAG material will surround uncertain and PAG type waste material. For closure of the waste rock facility reference Section 20.0 – Environmental Studies, Permitting, and Social or Community Impact. A 40% swell factor and an average specific gravity of 2.67 (bank) have been assumed for volume calculations. The dump design has a total capacity to contain 485 million tonnes, but it is over designed and only about 440 million tonnes of the capacity will be used. Prior to filling into the final footprint of the waste dump, the design should be optimized to minimize the footprint and minimize reclamation requirements. 16.5 Mine-Production Schedule Proven and probable reserves and the associated waste material were used to schedule mine production. Inferred resources inside of the pit were considered as waste. The final production schedule uses the number of trucks and shovels necessary to produce the ore required to be fed into the process plant and maintain stripping requirements for each case. Production scheduling was done using MineSched (version 9.1). This was summarized in Excel spreadsheets where additional waste re-handling was added to the schedule. Table 16-3 shows the mine production schedule, including re-handle from stockpiles, waste material re-handle, and sorter stockpile material movement requirements. For production scheduling, low-grade, medium-grade, and high-grade ore was designated. The medium-grade and high-grade cutoffs used 0.55 and 0.85 g-Au/t, respectively. Ore from the mine is to be sent from the pit directly to the crusher, or to a mill ore stockpile. During pre- stripping, high-grade, medium-grade, and low-grade ore is stockpiled in the stockpile area northeast of the waste dump facility. Low-grade ore is processed as part of the commissioning of the mill. This assumes a ramp up to full production of 25%, 50%, 75%, and 87.5% of full production throughput through the first 4 months prior to start of full production. High-grade and medium-grade ore is processed in the mill when mill capacity becomes fully available. For scheduling, three ore stockpiles are assumed: „ High-grade ore stockpile (> 0.85 g-Aug/t; „ Medium-grade stockpile (0.55 to 0.85 g-Au/t); and „ Low-grade stockpile (0.40 to 0.55 g-Au/t). The high-grade and medium-grade stockpiles are to be built within the low-grade stockpiling areas but will be exhausted during the first year of processing when mill capacity becomes available. During the life of mine, the low-grade stockpile is to be used as needed to feed the mill to full capacity. For this reason, the stockpile grows and shrinks through the life of mine. The maximum stockpile balance through the life of mine is estimated to be 21.0 million tonnes. Ultimate stockpile designs have been created north-east of the processing facility.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 222 Re-handling of stockpiled material will be done using a loader and trucks to haul ore to the crusher. Table 16-4 shows the yearly ore stockpile balances. Ore sent to the mill is shown in Table 16-5 and is a combination of ore shipped directly from the mine, and ore that is reclaimed from stockpiles. Ore sent to the mill is summarized based on the level of oxidation. The recovered ounces shown are based on the recoveries used for pit optimizations.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 223 Table 16-3: Annual Mine Production Schedule Pre-Prod Yr 1 Yr 2 Yr 3 Yr 4 Yr 5 Yr 6 Yr 7 Yr 8 Yr 9 Yr 10 Yr 11 Yr 12 Yr 13 Yr 14 Total Total Mined *StkPl K Tonnes 2,859 7,302 5,283 6,699 6,354 12,102 235 - - 1,000 10,903 8,172 - - - 60,908 g Au/t 0.77 0.94 0.47 0.52 0.47 0.63 0.48 - - 0.53 0.60 0.65 - - - 0.63 K Ozs Au 71 220 80 113 96 244 4 - - 17 211 172 - - - 1,227 Crusher K Tonnes - 8,836 10,330 17,795 9,232 17,750 8,749 7,178 13,482 17,750 17,750 17,799 127 - - 146,779 g Au/t - 1.26 0.86 1.04 0.85 1.10 0.87 0.64 0.63 0.70 0.93 1.18 1.05 - - 0.93 K Ozs Au - 358 286 592 252 629 246 149 274 397 528 674 4 - - 4,389 Total Ore Mined K Tonnes 2,859 16,138 15,613 24,495 15,586 29,852 8,984 7,178 13,482 18,750 28,653 25,970 127 - - 207,687 g Au/t 0.77 1.11 0.73 0.90 0.69 0.91 0.86 0.64 0.63 0.69 0.80 1.01 1.05 - - 0.84 K Ozs Au 71 578 366 705 348 872 249 149 274 414 739 846 4 - - 5,616 Mineralized Waste K Tonnes - - - - - - - - - - - - - - - - g Au/t - - - - - - - - - - - - - - - - K Ozs Au - - - - - - - - - - - - - - - - NonPag_Wst K Tonnes 1,720 150 20,484 8,711 20,829 22,261 58,227 37,390 18,570 6,948 1,496 24 - - - 196,810 Pag_Wst K Tonnes 5,433 8,897 18,469 17,473 36,445 27,894 17,272 18,276 24,290 25,310 21,567 3,887 - - - 225,212 Un_Wst K Tonnes 1,650 1,452 8,583 6,696 19,257 7,930 11,512 12,552 13,738 10,678 6,684 237 - - - 100,968 Total Waste Mined K Tonnes 8,802 10,498 47,536 32,880 76,531 58,085 87,011 68,218 56,598 42,935 29,747 4,148 - - - 522,990 Total Tonnes Mined K Tonnes 11,661 26,636 63,149 57,375 92,117 87,937 95,995 75,396 70,080 61,685 58,400 30,119 127 - - 730,677 Strip Ratio W:O 3.08 0.65 3.04 1.34 4.91 1.95 9.69 9.50 4.20 2.29 1.04 0.16 - 2.52 Re-Handle Material HG_StkPl K Tonnes - 1,419 3,212 3 265 - 1,626 - - - - - 2,288 - - 8,813 g Au/t - 1.40 1.25 1.39 1.16 - 1.13 - - - - - 1.06 - - 1.20 K Ozs Au - 64 129 0 10 - 59 - - - - - 78 - - 340 MG_StkPl K Tonnes - 2,041 39 - 744 - 4,111 - - - - - 8,497 - - 15,432 g Au/t - 0.69 0.62 - 0.67 - 0.67 - - - - - 0.66 - - 0.67 K Ozs Au - 45 1 - 16 - 88 - - - - - 181 - - 331 LG_StkPl K Tonnes - 165 4,168 - 7,509 - 3,264 10,620 1,647 - - - 6,838 2,451 - 36,663 g Au/t - 0.53 0.50 - 0.50 - 0.51 0.44 0.43 - - - 0.49 0.42 - 0.47 K Ozs Au - 3 67 - 121 - 53 149 23 - - - 107 33 - 556 Leach Re-handle K Tonnes - - - - - - - - - - - - - 13,354 - 13,354 g Au/t - - - - - - - - - - - - - 0.54 - 0.54 K Ozs Au - - - - - - - - - - - - - 232 - 232 Total Re-Handle K Tonnes - 3,625 7,420 3 8,518 - 9,001 10,620 1,647 - - - 17,623 15,805 - 74,262 g Au/t - 0.96 0.82 1.39 0.54 - 0.69 0.44 0.43 - - - 0.65 0.52 - 0.61 K Ozs Au - 112 197 0 147 - 200 149 23 - - - 366 265 - 1,459 Waste Re-handle K Tonnes - 1,555 603 3,848 435 877 - - - - 4,842 6,253 1,171 1,480 7,256 28,324 Sorter Rejects K Tonnes - 1,246 1,775 1,780 1,775 1,775 1,775 1,780 1,513 1,775 1,775 1,780 1,775 245 - 20,769 Sorter Reject Re-handle K Tonnes - - - - - - - - - - - - - - 20,769 20,769

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 224 Table 16-4: Annual Stockpile Balance Pre-Prod Yr 1 Yr 2 Yr 3 Yr 4 Yr 5 Yr 6 Yr 7 Yr 8 Yr 9 Yr 10 Yr 11 Yr 12 Yr 13 Hg_StkPl Added K Tonnes 858 3,773 - 268 - 1,626 - - - 53 1,106 1,129 - - g Au/t 1.13 1.33 - 1.17 - 1.13 - - - 1.08 1.07 1.06 - - K Ozs Au 31 161 - 10 - 59 - - - 2 38 38 - - Removed K Tonnes - 1,419 3,212 3 265 - 1,626 - - - - - 2,288 - g Au/t - 1.40 1.25 1.39 1.16 - 1.13 - - - - - 1.06 - K Ozs Au - 64 129 0 10 - 59 - - - - - 78 - Balance K Tonnes 858 3,212 - 265 - 1,626 - - - 53 1,159 2,288 - - g Au/t 1.13 1.25 - 1.16 - 1.13 - - - 1.08 1.07 1.06 - - K Ozs Au 31 129 - 10 - 59 - - - 2 40 78 - - Mg_StkPl Added K Tonnes 1,262 818 - 744 - 4,111 - - - 225 4,167 4,105 - - g Au/t 0.69 0.68 - 0.67 - 0.67 - - - 0.67 0.66 0.66 - - K Ozs Au 28 18 - 16 - 88 - - - 5 88 88 - - Removed K Tonnes - 2,041 39 - 744 - 4,111 - - - - - 8,497 - g Au/t - 0.69 0.62 - 0.67 - 0.67 - - - - - 0.66 - K Ozs Au - 45 1 - 16 - 88 - - - - - 181 - Balance K Tonnes 1,262 39 - 744 - 4,111 - - - 225 4,392 8,497 - - g Au/t 0.69 0.62 - 0.67 - 0.67 - - - 0.67 0.66 0.66 - - K Ozs Au 28 1 - 16 - 88 - - - 5 93 181 - - Lg_StkPl Added K Tonnes 738 2,711 5,283 5,688 6,354 6,365 235 - - 722 5,630 2,938 - - g Au/t 0.48 0.47 0.47 0.48 0.47 0.47 0.48 - - 0.45 0.47 0.48 - - K Ozs Au 11 41 80 87 96 97 4 - - 10 85 45 - - Removed K Tonnes - 165 4,168 - 7,509 - 3,264 10,620 1,647 - - - 6,838 2,451 g Au/t - 0.53 0.50 - 0.50 - 0.51 0.44 0.43 - - - 0.49 0.42 K Ozs Au - 3 67 - 121 - 53 149 23 - - - 107 33 Balance K Tonnes 738 3,284 4,399 10,086 8,931 15,297 12,267 1,647 - 722 6,351 9,290 2,451 - g Au/t 0.48 0.47 0.44 0.46 0.43 0.45 0.44 0.43 - 0.45 0.47 0.47 0.42 - K Ozs Au 11 50 63 150 124 221 172 23 - 10 95 141 33 - All StkPl Balance K Tonnes 2,859 6,536 4,399 11,095 8,931 21,033 12,267 1,647 - 1,000 11,902 20,074 2,451 - g Au/t 0.77 0.85 0.44 0.49 0.43 0.54 0.44 0.43 - 0.53 0.60 0.62 0.42 - K Ozs Au 71 179 63 175 124 368 172 23 - 17 228 400 33 -

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 225 Table 16-5: Annual Ore Delivery to the Mill Crusher Pre-Prod Yr 1 Yr 2 Yr 3 Yr 4 Yr 5 Yr 6 Yr 7 Yr 8 Yr 9 Yr 10 Yr 11 Yr 12 Yr 13 Total Sulfide Ore K Tonnes - 12,461 17,631 17,384 17,281 16,974 17,185 17,050 15,015 17,750 17,750 17,799 17,623 2,451 204,354 g Au/t - 1.17 0.85 1.04 0.70 1.12 0.79 0.52 0.61 0.70 0.93 1.18 0.65 0.42 0.84 K Ozs Au - 469 480 582 390 612 435 287 295 397 528 674 366 33 5,551 Recovery 0% 93% 92% 92% 91% 92% 92% 90% 91% 91% 92% 93% 91% 88% 92% K Ozs Au Rec - 434 440 537 356 565 399 258 267 362 485 624 333 30 5,089 Mixed Ore K Tonnes - - 61 358 385 473 359 441 68 - - - 127 - 2,272 g Au/t - - 0.58 0.75 0.55 0.68 0.59 0.44 0.42 - - - 1.05 - 0.62 K Ozs Au - - 1 9 7 10 7 6 1 - - - 4 - 45 Recovery 0% 0% 91% 91% 90% 91% 91% 89% 88% 0% 0% 0% 92% 0% 91% K Ozs Au Rec - - 1 8 6 9 6 5 1 - - - 4 - 41 Oxidized Ore K Tonnes - - 58 57 84 303 207 308 45 - - - - - 1,061 g Au/t - - 0.63 1.02 0.53 0.66 0.61 0.44 0.42 - - - - - 0.58 K Ozs Au - - 1 2 1 6 4 4 1 - - - - - 20 Recovery 0% 0% 91% 92% 90% 91% 91% 89% 88% 0% 0% 0% 0% 0% 90% K Ozs Au Rec - - 1 2 1 6 4 4 1 - - - - - 18 Total K Tonnes - 12,461 17,750 17,799 17,750 17,750 17,750 17,799 15,129 17,750 17,750 17,799 17,750 2,451 207,687 g Au/t - 1.17 0.85 1.04 0.70 1.10 0.78 0.52 0.61 0.70 0.93 1.18 0.65 0.42 0.84 K Ozs Au - 469 482 593 399 629 446 298 297 397 528 674 371 33 5,616 Recovery 0% 93% 92% 92% 91% 92% 92% 90% 91% 91% 92% 93% 91% 88% 92% K Ozs Au Rec - 434 442 546 363 580 408 267 269 362 485 624 337 30 5,148

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project October 2019 16.6 Equipment Selection and Productivities Mt Todd has been planned as an open-pit mine using large haul trucks, hydraulic shovels, and front-end loading equipment. Primary mine production is to be achieved using 31-cubic meter hydraulic shovels along with 226-tonne haul trucks, though final equipment selection may differ. Secondary mine production is to be achieved using 18-cubic meter loaders along with the 226-tonne trucks. Loaders will be used mostly to mine ore from the pit to the crusher, and for reclamation of ore from stockpiles. Some waste production from the loader is anticipated as well. Table 16-6 shows the maximum shovel productivity estimate based on scheduled time, availability, and truck and material parameters. This maximum productivity would require that trucks are always available and the shovels are always digging; however, that is not always the case. In-pit and ex-pit centerlines were drawn for each of the pits and destinations, including the waste dump, crusher, and ore stockpile. As the dump is very large, it was divided into 20 smaller volumes to account for haulage requirements during the life of mine. Truck speeds for each profile were calculated based on published rim-pull curve data. Maximum speed limits were also applied to ensure that safe operating conditions were adhered to and that productivities were achievable. Bench haulage routes were also drawn for each bench to ensure proper travel on the benches and that truck requirements are properly accounted for. Bench travel speed limits were applied to the profiles for both loaded and empty trucks. Mine production schedules were run using MineSched (version 9.1) mine scheduling software. The profiles and truck parameters were supplied to MineSched to calculate the productive truck hours required. An efficiency of 83% was used to derive operating hours from the productive hours. This accounts for inefficiencies in the operations that are found between the loading units and the dumping locations. This is similar to a 50-minute working hour. Incremental truck hours were added to waste haulage to account for waste material hauled to TSF 1 and TSF 2 for construction purposes. Haulage requirements for sorter tailings were estimated within cost sheets using a constant cycle time. The material would be loaded into a truck from a silo and the silo bin is sized to use the mine fleet. It was determined that a single truck would be able to take care of the haulage needs for the sorter. Loading-unit hours were estimated using 83% efficiency and the production rate for loading equipment. The schedule was constrained using tonnage on a period basis to balance the use of loading and haulage equipment. Availability was estimated dependent on the age of the piece of equipment. Availabilities start out at 90% and decrement 1% per year until they reach 85%, and then they are kept constant. Availabilities, efficiencies, operating hours, and load and haul equipment requirements are shown in Table 16-7.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project October 2019 Table 16-6: Maximum Loader Productivity Estimate Description Unit All Rock MATERIAL PROPERTIES Material SG (BCM) t/cm (Wet) 2.70 Material SG (Loose) t/cm (Wet) 1.93 Material SG (BCM Dry) t/cm (Dry) 2.50 Material SG (LCM Dry) t/cm (Dry) 1.79 Swell Factor 1.4 DAILY SCHEDULE Shifts per Day Hours per Shift shift/day hr/shift 2 12 Theoretical Hours per Day hrs/day 24 Shift Startup / Shutdown Lunch Breaks Operational Standby hrs/shift hrs/shift hrs/shift hrs/shift 0.5 0.5 0.25 0.25 Total Standby / Shift Total Standby / Day hrs/shift hrs/day 1.50 3.00 Available Work Hours hrs/day 21.00 Schedule Efficiency % 87.5 Unit 31 cm Hyd 226 T Trks 18 cm FEL 226 T Trks LOADING PARAMETERS Shovel Mech. Avail. % 85% 85% Operating Efficiency % 83% 83% Bucket Capacity m3 31 18 Bucket Fill Factor % 95% 95% Avg. Cycle Time Sec 34 50 TRUCK PARAMETERS Truck Mech. Avail. % 85% 85% Operating Efficiency % 83% 83% Volume Capacity m3 176 176 Tonnage Capacity lt (Wet) 227 227 Truck Spot Time Sec 24 24 SHOVEL PRODUCTIVITY Effective Bucket Capacity Cyd 29.45 17.10 Tonnes per Pass – Wet lst (Wet) 56.8 33.0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project October 2019 Unit 31 cm Hyd 226 T Trks 18 cm FEL 226 T Trks Tonnes per Pass – Dry lst (Dry) 52.6 30.5 Theoretical Passes – Vol passes 5.98 10.29 Theoretical Passes – Wt passes 4.00 6.88 Actual Passes Used passes 4.0 7.0 Truck Tonnage – Wet wmt/load 226 226 Truck Tonnage – Dry dmt/load 210 210 Truck Capacity Utilized – Vol % 67% 67% Truck Capacity Utilized – Wt % 100% 100% Load Time min 2.67 6.23 Theoretical Productivity dst/hr 4,729 2,023 Tonnes per Operating Hour dst/hr 3,930 1,680 Tonnes Per Day dst/day 70,200 30,000 Potential – 355 days/year t/year 24,921,000 10,650,000

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 229 Table 16-7: Annual Load and Haul Equipment Requirements Pre-Prod Yr 1 Yr 2 Yr 3 Yr 4 Yr 5 Yr 6 Yr 7 Yr 8 Yr 9 Yr 10 Yr 11 Yr 12 Yr 13 Yr 14 Total HAULAGE REQUIREMENTS Productive Hours Hrs 13,186 45,149 109,615 106,344 174,037 178,598 189,570 194,550 212,805 205,229 210,421 112,304 15,234 14,382 30,033 1,811,46 2 Operating Efficiency % 83% 83% 83% 83% 83% 83% 83% 83% 83% 83% 83% 83% 83% 83% 83% 1743% Operating Hours Hrs 15,887 54,397 132,067 128,125 209,683 215,179 228,398 234,397 256,391 247,264 253,520 135,306 18,354 17,328 36,184 2,182,48 5 Number of Trucks # 8 11 22 27 33 35 37 38 41 41 41 22 6 6 6 376 Truck Availability % 90% 90% 89% 89% 88% 88% 87% 86% 86% 85% 85% 85% 86% 85% 85% Available Operating Hours Hrs 19,188 71,686 136,420 168,364 214,038 224,555 233,608 238,718 255,731 254,494 254,276 136,910 37,334 37,115 37,115 2,319,90 2 Use of Available Hours % 86% 76% 97% 76% 98% 96% 98% 98% 100% 97% 100% 99% 49% 47% 97% 94% Tonnes per Operating Hour t/Hr 731 585 539 478 482 413 460 367 280 249 249 269 1,031 998 775 391 HYDRAULIC SHOVEL USAGE Number of Shovels # 2 2 3 4 4 4 4 4 3 3 3 2 1 1 1 3.3 Availability % 90.0% 89.4% 88.9% 88.2% 87.6% 86.6% 85.9% 85.4% 85.2% 85.0% 85.0% 85.0% 85.0% 85.0% 85.0% 86.4% Operating Efficiency % 83% 83% 83% 83% 83% 83% 83% 83% 83% 83% 83% 83% 83% 83% 83% 83.0% Available Operating Hrs Op Hrs 4,834 13,009 18,860 20,836 25,509 25,217 25,005 24,930 18,601 18,558 18,558 12,407 6,186 6,186 6,186 244,880 Tonnes Mined K Tonnes 11,661 25,732 60,623 51,413 88,432 82,918 88,315 69,364 65,174 57,367 54,312 28,914 15,975 14,225 19,617 734,044 Operating Hours Op Hrs 2,911 6,555 15,445 13,098 22,529 21,124 22,500 17,671 16,604 14,615 13,837 7,366 4,070 3,624 4,998 186,948 Use of Available Operating Hours % 60% 50% 82% 63% 88% 84% 90% 71% 89% 79% 75% 59% 66% 59% 81% 76% FRONT END LOADERS Number of Loaders # - 1 2 2 2 2 2 2 2 2 2 2 1 1 1 1.8 Availability % 0% 90% 89% 88% 87% 86% 85% 85% 85% 85% 85% 85% 85% 85% 85% 86% Operating Efficiency % 0.0% 83.0% 83.0% 83.0% 83.0% 83.0% 83.0% 83.0% 83.0% 83.0% 83.0% 83.0% 83.0% 83.0% 83.0% 83.0% Available Operating Hrs Op Hrs - 6,550 12,954 12,844 12,663 12,463 12,372 12,407 12,372 12,372 12,372 12,407 6,186 6,186 6,186 150,680 Tonnes Mined K Tonnes - 6,085 10,548 9,812 12,638 5,896 16,681 16,652 6,552 4,318 8,930 7,458 2,946 3,061 8,407 119,988 Operating Hours Op Hrs - 3,624 6,282 5,843 7,526 3,511 9,934 9,916 3,902 2,571 5,318 4,441 1,754 1,823 5,007 71,454 Use of Available Operating Hours % 0% 55% 48% 45% 59% 28% 80% 80% 32% 21% 43% 36% 28% 29% 81% 47%

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project October 2019 16.7 Mine Personnel Mine personnel estimates include both operating and mine-staff personnel. Operating personnel are estimated as the number of people required to operate trucks, loading equipment, and support equipment to achieve the production schedule. Mine staff is based on the people required for supervision and support of mine production. The mine staff organizational chart is shown in Figure 16-1. The estimated number of mine personnel required to execute the mine plan is shown in Table 16-8. Salaries for each position were estimated based on information received from Vista. Salaries include an allowance for benefits at a factor of 27% of the base salary for each position. Note that the mine personnel do not include contractors. Vista anticipates using a Maintenance and Repair Contract (“MARC”) to maintain the mining fleet into the third year of operation. After that time, Vista will operate all maintenance crews. For costing, the MARC costs were reduced to take into account savings by lowering contractor’s overhead. Maintenance foremen were added to personnel along with another planner starting in year 3 as part of the maintenance responsibility takeover. However, since the maintenance cost used includes labor, the mechanics are not reflected in the total count for personnel. This would add approximately 80 mechanics, servicemen, and welders.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project October 2019 Figure 16-1: Mine Organizational Chart

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 232 Table 16-8: Mine Personnel Requirements Pre- Prod Yr 1 Yr 2 Yr 3 Yr 4 Yr 5 Yr 6 Yr 7 Yr 8 Yr 9 Yr 10 Yr 11 Yr 12 Yr 13 Yr 14 MINE OVERHEAD Mine Manager 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Mine Clerk 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Mine Shift Foremen 8 9 9 10 12 12 12 12 12 12 12 9 6 6 6 Mine Trainer 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Blaster 2 2 2 2 2 2 2 2 2 2 2 2 2 - - Blaster's Helper 2 2 2 2 2 2 2 2 2 2 2 2 2 - - MINE PRODUCTION Loading Operators 5 7 13 11 17 15 18 18 12 12 12 9 5 5 6 Haul Truck Operators 20 33 63 78 100 106 111 114 123 123 123 66 18 18 18 Drill Operators 13 15 30 31 42 45 42 33 33 31 33 20 1 - - Support Equipment Operators 14 14 18 20 20 20 24 24 24 24 21 18 12 12 12 Total Mine Operating 67 85 140 157 198 205 214 208 211 209 208 129 49 44 45 MINE MAINTENANCE Maintenance Superintendent 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Maintenance Foremen - - - 3 3 3 3 3 3 3 3 3 3 1 1 Light Vehicle Mechanics 2 - 2 2 2 2 2 2 2 2 2 2 2 1 1 Tiremen 2 - 2 2 2 2 2 2 2 2 2 2 2 2 2 Shop Laborers 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 Maintenance Planner 1 1 1 2 2 2 2 2 2 2 2 2 2 1 1 Service, Fuel, & Lube 6 6 6 6 6 6 6 6 6 6 6 6 6 3 3 *Maintenance Labor 80 80 80 80 80 80 80 80 80 80 40 40 Total Mine Maintenance 14 10 14 98 98 98 98 98 98 98 98 98 98 51 51

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 233 Pre- Prod Yr 1 Yr 2 Yr 3 Yr 4 Yr 5 Yr 6 Yr 7 Yr 8 Yr 9 Yr 10 Yr 11 Yr 12 Yr 13 Yr 14 ENGINEERING Chief Engineer 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Mine Surveyors 1 2 2 2 2 2 2 2 2 2 2 2 1 2 1 Surveyor Helper 2 2 2 2 2 2 2 2 2 2 2 2 1 2 1 Mine Engineer 2 3 3 3 3 3 3 3 3 3 3 3 1 1 1 Total Engineering 6 8 8 8 8 8 8 8 8 8 8 8 4 6 4 MINE GEOLOGY Chief Geologist 1 1 1 1 1 1 1 1 1 1 1 1 1 - - Ore Control Geologist 2 2 2 2 2 2 2 2 2 2 2 2 2 - - Sampler 2 2 2 2 2 2 2 2 2 2 2 2 2 - - Total Geology 5 5 5 5 5 5 5 5 5 5 5 5 5 - - TOTAL MINE OPERATIONS WORKFORCE Mine Operations 67 85 140 157 198 205 214 208 211 209 208 129 49 44 45 Mine Maintenance* 14 10 14 18 18 18 18 18 18 18 18 18 18 11 11 Engineering 6 8 8 8 8 8 8 8 8 8 8 8 4 6 4 Geology 5 5 5 5 5 5 5 5 5 5 5 5 5 5 - Total 92 108 167 268 309 316 325 319 322 320 319 240 156 106 100 * During year 3 the MARC would be removed and additional maintenance labor would be required to maintain the fleet.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 234 17.0 RECOVERY METHODS The key criteria used in the process design of the Process Plant have been largely derived from metallurgical testwork and, where appropriate, based on the QP’s experience and industry norms. The design criteria and flowsheet development are discussed in this section. 17.1 Process Design Criteria Detailed process design criteria have been developed for the Project. The nominal headline design criteria are listed as follows: Table 17-1: Headline Design Criteria Unit 50,000 tpd Annual Ore Feed Rate Mt/a 17.75 Operating Days per Year d/a 355 Daily Ore Feed Rate t/d 50,000 Crushing Rate (6,637 hours per year availability) tph 2,674 HPGR Rate (7,838 hours per year) tph 2,264 Ore Sorting Rate (7,838 hours per year) tph 408 Milling Rate (7,838 hours per year) tph 2,055 Gold Head Grade g/t 0.82 Copper Head Grade % 0.055 Cyanide Soluble Copper % 0.0024 Ore Specific Gravity t/m3 2.76 Primary Grind P80 to Secondary Grind μm 250 Grind P80 to Leach μm 40 Gold Recovery % 91.9 Gold Production (average) oz/d 1,165 Gold Production (average) oz/a 413,400 The testwork results collated from the 2011 and 2012 testing campaigns and additional metallurgical and process test work conducted in 2016/2017/2018/2019, together with the process design criteria, were used to develop the process flow sheet and mass balance.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 235 17.2 Flow Sheet Development A schematic diagram of the process flowsheet is presented in Figure 17-1. 17.2.1 Crushing Modeling Impact crush work index (CWi) tests were performed on eighty individual samples from the 2011 drill cores. The CWi values ranged from 3.2 kilowatt hours per tonne (kWh/t) to 26.5 kWh/t. For design purposes, a CWi of 20 kWh/t was selected, 75% of the maximum. Unconfined compressive strength (UCS) was measured on 16 samples. The values ranged from 14 megapascals (MPa) (med strong) to 183 MPa (very strong). Eighty percent of the results were in the strong to very strong designation of ore hardness. The run of mine ore from the pit is expect to have a maximum particle size of 1000 mm and F80 to the primary crusher of 400 mm. Two stages of crushing, primary and secondary are required to reduce particle size to a P80 of 31.5 mm, required as feed to the HPGR tertiary crushers. A single gyratory crusher is sized for the primary duty reducing ore size to a nominal P80 of 130 mm. Two secondary cone crushers operating in parallel and in closed circuit with two sizing screens cutting at 40 mm, are used to produce the feed to the HPGRs at product size P80 of 31.5 mm.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 236 Figure 17-1: Simplified Process Flow Diagram

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 237 17.2.2 Primary Crusher The primary crusher power was calculated using both the FLSmidth gyratory calculation model and the Metso Bruno model. Using the CWi of 20 kWh/t and a fall through percentage of zero to simulate peak conditions, both models provided peak primary crushing power requirements of a nominal 574 kW and 576 kW respectively to reduce a feed F80 of 400 mm to a product P80 of 130 mm. 17.2.3 Secondary Crushers Secondary crushing with closed circuit screening was modelled by FLSmidth. Two Raptor 1300 cone crushers operating in parallel are used to reduce the primary crusher product to a final product P80 of 31.5 mm. 17.2.4 HPGR HPGR power requirements to reduce the HPGR feed to a final product P80 of 3.25 mm was shown by the Polysius testwork to be 1.9 kWh per tonne of feed to the HPGR. The feed to the HPGR is the sum of new feed plus the recirculating load screen oversize material, less Ore Sorting reject. The total feed to the HPGR is two times the fresh feed rate. HPGR testwork supported vendor recommendations for two HPGR Polycom PM8-24/17, each equipped with 2 x 2,650 kW drives. 17.2.5 Ore Sorting The coarse fraction (plus 16mm) from the HPGR will be sent to the ore sorting equipment for separating the gold-bearing sulfide minerals and quartz veining from non-gold bearing waste material. 17.2.6 Grinding Modeling A variety of internal models were used to provide the initial baseline ball mill power requirements and vendors were approached for proposals. The most price competitive and technically acceptable submission was then selected for further interaction, with the vendor calculations compared against internal calculations. The circuit incorporates two dual pinion drive ball mills. 17.2.7 Thickener / Leach / CIP Design THICKENER Based on thickener sizing parameters received from RDI Minerals, that were based on additional 2019 rheology and settling test work undertaken by Pocock Industrial for a final grind size of 40um, a 67 m Pre- Leach thickener for the 50,000 tpd case and a 55 m Pre-leach thickener for the 33,000 tpd was recommended. The test work also reported an Underflow solids of approximately 53.88% solids was achievable for both of the above sizes for each respective duty.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 238 LEACH AND ADSORPTION The optimum leach / adsorption density as determined by SPX testwork was 55% solids for the previous grind size of 90 um. This was changed to 45% solids as the current grind size of 40ʅm would result in an excessive viscosity in 55% slurry. The leach and adsorption circuits were modelled. A six-stage adsorption is required to minimize solution losses. Dissolved gold in residue solution will be ч0.010 ppm. At the planned gold head grade, the system will produce a loaded carbon head grade of approximately 1,250 g/t, and carbon movement requirements will be in the order of 30 tpd. 17.3 Description of Process Areas 17.3.1 Area 3100 – Crushing Circuit Availabilities The crushing circuit availabilities coupled with the ore crusher work index are the two predominant factors in sizing crusher circuits. Rather than assuming a standard availability of between 70% and 75%, a review of the previous primary crusher operations at Mt Todd was conducted. When removing the downtime periods when the crushing system was not required, the average availability for the remaining duration was 59%. Additionally, the QP [Deepak Malhotra, Ph.D., SME RM] reviewed results from a two-year study and dynamic simulation of a large-scale crusher operation in the tropics, which indicated the downtime was apportioned as follows: „ Dump hopper empty 19.2% (mining not keeping up) „ Cannot discharge 15.6% (downstream equipment interruptions) „ Operating Breakdown 0.6% (crusher specific) „ Mechanical breakdown 1.2% (crusher specific) „ Electrical breakdown 2.3% (crusher specific) „ Planned maintenance 2.5% (crusher specific) The combination of this data coupled with the historical Mt Todd crusher downtime led to an initial crusher circuit availability of 60% being selected, with first pass crushing equipment initially being selected on this basis. Subsequently it was agreed with the mining design consultant MDA that the costs of an extra loader and build of an emergency stockpile on the ROM pad be included and to remove the downtime attributable to mining lack of supply in its entirety. This resulted in an availability of 75.8%, 6,637 operating hours per year. 17.3.1.1 Crushing Circuit Design The crushing circuit was chosen based on reliability and similarity to existing mining operations. It consists of a single Primary Crusher in an open loop configuration and two Secondary Crushers in parallel in a closed loop configuration with sized output conveyed to a buffer stockpile, providing three days live capacity. The primary and the secondary crushers discharge onto a common conveyor that feeds the Coarse Ore Screens. This configuration allows reduced conveyor footprint and maximum plant productivity.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 239 The Coarse Ore Screens will be fed by vibrating feeders, which regulate the flow from the feed bins. This arrangement maximizes the efficiency of the screens by ensuring full coverage of screen decks at controlled bed depth. Crusher area dust is controlled by dust collection at the screens and dust suppression in all other dust generating areas. 17.3.2 Area 3200 – Coarse Ore Stockpile, Reclaim, HPGR and Ore Sorting A plant availability factor of 89.5% of 365 days/year has been used for the HPGRs and subsequent downstream processes, which is 7,838 operating hours per year. HPGR availability in large hard rock applications ranges from 89% to 92%, with some operations reporting periods of 95% availability when roll change has not been required (Boddington). It is considered appropriate to use a conservative availability factor of 89.5% of the annual 8,760 hours for Mt Todd ore due to its ore hardness. The coarse ore stockpile will have approximately three days of total capacity between the secondary crushers and the HPGRs, with 23% of that total capacity representing the live volume. Ore will be removed from beneath the Coarse Ore Stockpile by two Apron Feeders. Two HPGRs will operate in parallel. The HPGRs are protected from tramp metal by installation of metal detectors on feed conveyors. A common HPGR Product Conveyor will receive the discharge from the HPGRs and convey the material to the Fines Screens Feed Bins. The HPGR fines screens are double decked, cutting at nominal 4.5 mm to produce an underflow product at P80 of 3.2 mm and 16mm to produce a mid and an oversize. The screens operate as wet screens with high pressure spray water applied to the decks to assist with screen efficiency. The screen mid material (+4.5mm-16mm), ~3-5% moisture, will be conveyed back to the HPGR feed bins and the screen oversize (+16mm) material will be conveyed to Ore Sorting. Ore Sorting receives a nominal 408 t/h. Ore Sorting comprises two stages, XRT and Laser sorting. The two stages together reject 210 t/h, representing approximately 10% of plant feed. The above reject performance and nominal gold loss was derived from bulk ore sorting test work completed at the Tomra sorting facility. Gold lost to Ore Sorting reject is minor at a nominal 1.3% of gold entering plant. 17.3.3 Area 3300 – Grinding and Classification Two Ball mills will be used. The parallel Ball Mill circuits are in a conventional configuration. Fresh feed from the fines screens underflow will gravitate to the mill discharge hopper and will be pumped together with the mill discharge slurry to the Cyclones. The cyclone underflow will gravitate to the ball mill feed. The overflow will gravitate to the Secondary Grind feed sump. The secondary grinding cyclone overflow will be pumped to the pre-leach thickener and the underflow will be sent to the VXP mills for secondary grinding. An automated ball charging system will be provided to deliver approximately 15 tonnes of balls per day to each mill.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 240 17.3.4 Area 3400 – Pre-Leach Thickening, Leach Conditioning, Leach and CIP In order to achieve the required 45% solids feed to the leach and CIP tanks, a Pre-Leach Thickener will be used. Two Leach Conditioning stages will be incorporated ahead of Leach. These tanks will be sized to deliver a total residence time of 4 hours. In these stages, the ore is treated with lime which inhibits reaction of cyanide with pyrites and pyrrhotites by way of forming a lime coating around these gangue components. The leach and adsorption tanks will be sized to deliver a total residence time of 24 hours for Leach and 6 hours for adsorption, as determined by the test work. For both cases, leach and adsorption will consist of eighteen mechanically agitated tanks in total. There will be twelve leach tanks and six adsorption tanks. In order to maximize the gold adsorption kinetics, lead nitrate will be added, oxygen will be provided by sparging compressed air into the leach tanks. Each Leach and CIP Tank can be bypassed for maintenance purposes. Carbon will be regularly pumped upstream from downstream CIP Tanks in a conventional counter-current configuration. The adsorption tanks will be equipped with Kemix interstage carbon screens. The pumping screens will be used to generate the overflow head required for downstream slurry advance. Carbon Safety Screens will catch any fugitive carbon from the tails slurry. Usable carbon will be returned to the circuit, undersize carbon will report directly out of the circuit via detoxification and tails. 17.3.5 Area 3500 – Desorption, Goldroom and Carbon Regeneration Loaded carbon will be acid washed in an Acid Wash Column, then stripped of copper and gold in an Elution Column. Cold cyanide wash will be used to strip adsorbed copper prior to hot caustic cyanide wash to strip gold. Acid wash effluent and copper wash effluent will be pumped to the detox tanks. The elution and electrowinning process will be the Anglo American Research Laboratories configuration. Eluant will be pumped through the column, heated to 120 deg°C, and collected as loaded eluate in one of two eluate tanks. The desorption circuit will be batch and will take up to 8 hours. The columns are sized to ensure that two elution batches can be performed in a day. After the elution is completed and the carbon is stripped of its gold to about 10 g/t Au, the eluate will be processed through the electrowinning circuit for deposition of gold onto cathodes. The electrowinning circuit will be batch and take up to 8 hours, or until the gold in solution reduces to less than 10 ppm. The Goldroom consisting of Electrowinning, Drying and Smelting facilities will be supplied as a vendor package. Stripped carbon will be regenerated using an indirect heated horizontal rotary kiln. 17.3.6 Area 3600 – Detoxification and Tailings Two Detoxification Tanks in series will be used to minimize short-circuiting and sized to ensure the required residence time of one hour is achieved. The second Detox Tank will cascade overflow to a Tailings Pump Hopper from where the tailings will be pumped to the Tailings Storage Facility. Future booster pumps will be required once the second tailings facility is operational. A duty/standby configuration of pumps will be used to ensure continuous operation.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 241 17.3.7 Area 3700 – Reagents Sodium Meta Bi-Sulfite (SMBS) will be delivered to site as a 95% pure solid powder in sea containers. A container tipper and solids handling equipment will transfer the powder from the storage containers to the mixing tank. SMBS will be mixed to 20% w/v in solution and dosed to the detoxification tanks via duty/stand- by dosing pumps. Dust extraction equipment is present at all transfer points of the solids handling and the area where solids handling takes place will be well ventilated. The SMBS solution will have storage for 3 days of nominal usage. The Sodium Cyanide for Leaching and Elution will be delivered as briquettes in a bulk tanker. The sodium cyanide will be consumed at a rate of approximately 39 tpd. The solids will be dissolved in the tanker and cyanide solution will be transferred into a mixing tank to ensure full dissolution. The cyanide solution will then be transferred into four storage tanks allowing seven days nominal capacity. There will be a secured and covered facility to store cyanide as emergency storage. The Hydrochloric Acid (HCL) for the Acid Wash Column will be delivered as a 33% HCl solution and will have storage for 20 days of nominal usage. Lime will be delivered as 92% active quick lime powder in road tankers. The lime will be pneumatically transferred to storage silos approximately 200 tonnes capacity. Lime will be slaked on a daily basis. Milk of lime will be distributed from a lime surge tank to Leach. Sodium Hydroxide (NaOH) will be delivered as a powder in bulk bags and mixed to produce a 50% NaOH solution. Sodium hydroxide is only consumed periodically and therefore does not require an additional storage tank beyond the mixing tank. A nominal 20-day dry solids storage capacity was included into the design. The lead nitrate for the leach circuit will be delivered as a powder in bulk bags and mixed to produce a 20% solution. The lead nitrate solution will have storage for seven days of nominal usage. 17.3.8 Area 3800 – Process Plant Services Approximately 800 normal meters cubed per hour (Nm3/h) of medium pressure process air will be used to service the air requirements for leach and adsorption. Detoxification will be serviced by medium pressure air blowers at a consumption rate of approximately 5,200 Nm3/h. High pressure compressors are used to provide plant and instrument air. Raw water will be supplied via the Raw Water Dam and will service the process water, fire water and gland seal water requirements. Raw water will also service the water treatment plant for potable water required at the mining facilities, process plant, powerhouse and camp. The nominal raw water consumption will be ~800 m3/h and will occasionally peak at 2,200 m3/h during the dry season. Process plant water will be predominantly made-up of tailings decant return water and raw water. Process water will be used for dilution and density control in the grinding circuit.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 242 17.4 Process Water The water reticulation system for the process plant will consist of the following: „ Raw water supply; „ Potable water supply; „ Fire water supply; „ Gland service water supply; and „ Process water supply. Raw water will be delivered from the raw water dam (RWD) to the 9,600 m3 process plant raw water tank. This water will be used as make-up water for the process water supply, emergency firefighting supply, gland seal, dust suppression, plant clean-up hosing stations, powerhouse, mining facilities and water for the reagents make-up. The fire water supply will be drawn from the reserve in the raw water tank providing water to the plant site fire water distribution system. Gland service water for the main plant site will be drawn from the raw water tank. It will be used to supply gland service water for slurry pumps in the plant. The process water system will include a 9,600 m3 storage tank. Process water will be supplied to the plant via centrifugal pumps, one operating and one stand-by unit. This water supply will be used for process stream dilution and for use as spray water for the screens. The pre-leach thickener, tailings dam decant water and raw water all report to the process water tank. 17.4.1 Process Compressed Air The plant and instrument air supply systems for the process plant will consist of high pressure compressed air units in the following locations: „ Primary Crushing (duty only); „ Reclaim Tunnel (duty only); „ HPGRs (duty only); „ Grinding and Classification (duty/stand-by); and „ Leach and CIP (duty/stand-by). Twin-screw compressors at each location will supply plant air and instrument air to the buildings in which they are located. The air discharging from each compressor will be fed to a plant air receiver and distributed throughout the building. An off-take from the discharge of the plant air receiver will be dedicated to instrument air which will pass through a refrigerant dryer with pre and post filters to an instrument air receiver. This air will be used for instrument air purposes with the required air quality achieved. The remainder of the air generated by the compressors will be used for general plant air duties. The dry areas of the plant will only have a single duty compressor due to the limited requirement of plant and instrument air whereas the wet plant areas will have a duty/standby arrangement. A dedicated low pressure compressed air system in a duty/stand-by arrangement will be located in the CIP area of the plant for process air in the leach and CIP tanks. The CIP process compressors will deliver air at the required pressure and flow for injection into the leach and CIP tanks.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 243 Similarly, a dedicated low-pressure blower air system in a duty/stand-by arrangement will be located in the cyanide detoxification area of the plant for process air in the cyanide detoxification tanks. 17.5 Plant Mobile Equipment The plant mobile equipment will be as follows: Table 17-2: Mobile Equipment for Process Plant Light Vehicles Quantity Landcruiser wagon 2 Dual cab Utes 21 Tray top Ute 9 Troop carrier (ambulance) 1 Bus/troop carrier (15-seat) 1 Coach 3 Subtotal 27 Process Plant Mobile Equipment Quantity Loader – Cat 966G Allowed for in mining Tool Carrier – Cat IT28 1 Bob Cat – Mustang Case 1 Crane – 15-t Franna 1 Hiab Truck – 7-t 1 Service Truck – 2-t 1 2-t Forklift – allowance 2 25-t Container Forklift 1 80-t Crane 1 Mill Relining Machine 1 Subtotal 10

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 244 18.0 PROJECT INFRASTRUCTURE This section is based on 50,000 tpd operation. 18.1 Facility 2000 – Mine The following section provides a description of the Mine Support Facilities and Mine Support Services that have been developed to support the mining activities. 18.1.1 Area 2300 – Mine Support Facilities Area 2300 Mine Support Facilities consists of the buildings and services for the maintenance and repair of the mine vehicle fleet including Heavy Vehicles (HV). The area is located along the haul road adjacent to the proposed stockpile, between the Pit and the existing Tailings Storage Facility. 18.1.1.1 Sub-Area 2305 – Support Facilities – HV Workshop/Warehouse The Workshop Facility will consist of six Dome Shelter structures mounted on sea containers with concrete floors. The sea containers come equipped as Site Offices, Store Services, Store Consumables, Equipment Repair and Lube Storage and Dispensing facilities for the maintenance and servicing of HVs that are used for mining operations. The Workshop will be approximately 85.6 m by 24.4 m and sized to service Caterpillar 793F mining trucks. The Warehouse Facility will consist of one Dome Shelter structure mounted on sea containers with a concrete floor. The Warehouse Facility will be approximately 21.7 m by 24.4 m in size. The sea containers come equipped as Site Offices, Rigging Container, Equipment Repair Workshop and Stores Consumable Container for the storage of parts, components, spares and the like, used by the HV Workshop for vehicle repair. The HV Workshops and Warehouse Facilities will be complete with all services including power, lighting, communications, lubes, compressed air, water, specialist equipment and other services necessary for the maintenance of the mine vehicle fleet. The Dome Shelters will be constructed of steel frame and tensile fabric with a fabric life expectancy of 10 years. A mobile crane will be used externally to the Dome Shelters for the lifting and removal of vehicle parts. 18.1.1.2 Sub-Area 2310 Support Facilities – Bulk Fuel Storage The Bulk Fuel Storage will consist of the relocated 600 kL tank complete with six new bowsers for dispensing into the HV fleet and one new 110 kL self-bunded diesel fuel tank complete with one bowser for dispensing into the LV’s. The new 110 kL tank will be utilized for refueling the Mine fleet when the 600 kL tank is not in service and will be located adjacent to the HV Workshop.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 245 18.1.1.3 Sub-Area 2315 – Support Facilities – HV Washdown The HV Washdown Facility will primarily be used for washing down the body and undercarriage of heavy vehicles prior to entering the HV Workshop. The facility will consist of a single bay with raised platforms with stair access to four manually operated high pressure water cannons. The run-off water will be connected to the oily water separator and will include drive-in concrete sumps and pits for waste water storage and recovery. The entire facility’s footprint is 18 m by 21.8 m and is sized to service Caterpillar 793F mining trucks. 18.1.1.4 Sub-Area 2320 – Support Facilities – Crib / Ablutions / Lockers The Crib / Ablutions / Lockers Facilities will be a transportable building used by mining personnel and is located adjacent to the HV Workshop. The building will include the necessary system furniture. The Crib Area will also double as a Pre Start Area. The building will be sized to serve 75 people per shift and cover approximately 19.8 m by 14.4 m. 18.1.1.5 Sub-Area 2325 – Support Facilities – HV Tire Change The Tire Change Facility will consist of one Dome Shelter mounted on sea containers with a concrete floor. The sea containers come equipped as Tire Change Workshop and Store Consumables for the maintenance and changing of HV tires. The Tire Change Facility will be approximately 26.9 m by 18.1 m and sized to service Caterpillar 793F mining trucks. The Tire Change Facility will be complete with services including power, lighting, communications, compressed air, water, specialist equipment and other services necessary for the changing of tires. The Dome Shelter will be constructed of steel frame and tensile fabric with a fabric life expectancy of 10 years. 18.1.1.6 Sub-Area 2335 – Support Facilities – Lube Storage The Lube Storage Facility will consist of a bunded concrete slab for the storage of Intermediate Bulk Containers (IBCs) containing oils and lubricants for the servicing of HVs. The Lube Storage Facility will be located in-between the HV Workshop and the Fuel Storage Facility. Full IBCs will replace containerized IBCs within the Workshops. Lube will be distributed manually. Used oil will be collected in a designated area for approved recycle/disposal. 18.1.1.7 Sub-Area 2340 – Support Facilities – ANFO / Magazine Facility The Ammonium Nitrate Fuel Oil (ANFO) facility is capable of distribution of 10,000 tpa. It is a secure compound for the Ammonium Nitrate (AN), Ammonium Nitrate Emulsion (ANE) and diesel fuel. The facility includes an area for AN storage, concrete hardstand for AN transfer to a Mobile Process Unit (MPU) and containment pond for spill material. The ANE is tank stored on concrete plinths with air compressor and pumps for in-loading and out-loading of emulsion. The diesel is stored in a 110 kL self-bunded tank and includes a spill containment unit.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 246 Magazine storage will consist of two secured modified shipping containers for the storage of detonators, accessories and explosives. The magazines are located adjacent to the ANFO Facility and are surrounded by earth bunding and secure fencing. The MPU will be used to transport, mix and deliver ANFO to the mine. A transportable building will be provided to include Office / Crib / Ablution facilities at the Site for driver and delivery personnel. The ANFO facility footprint is approximately 84.7 m by 128.5 m, excluding the diesel tank. 18.1.1.8 Sub-Area 2345 – Support Facilities – Mining Offices The Mining Offices will be a transportable building used by mining personnel and is located adjacent to the HV Workshop. The building will include a kitchen, ablutions, cellular and open planned offices, meeting rooms, training spaces and necessary system furniture. The footprint of the Mining Offices is approximately 24 m by 16.5 m and will be sized to account for 25 people. 18.1.1.9 Sub-Area 2355 – Support Facilities – Core Shed The Core Storage Facility will consist of one Dome Shelter mounted on sea containers with a sealed asphalt floor for the storage of core samples at the mine support area. The sea containers will be equipped with racking for additional storage. The Core Storage facility will be complete with power and lighting and located north-east of the mining offices. The Dome Shelter will be constructed of steel frame and tensile fabric with a fabric life expectancy of 10 years. The Core Storage Facility has a footprint of approximately 48.8 m by 47.3 m. 18.1.2 Area 2400 – Mine Support Services Mine Support Services consists of the services for the Mine Support Facilities. 18.1.2.1 Sub-Area 2410 – Support Services – Potable Water Potable water will be provided to the Mine Support Facilities from the Process Plant Area via pipework in common services trenching. 18.1.2.2 Sub-Area 2420 – Support Services – Raw Water Raw water will be provided to the HV Washdown storage tank at the Mine Support Facilities via a connection from the raw water pipework running along the existing haul road to the Process Plant Area. 18.1.2.3 Sub-Area 2430 – Support Services – Fire Water The Fire Water Main will be provided to the Mine Support Facilities and camps from the Process Plant Area via pipework in common services trenching. Fire hydrants will be provided at required locations.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 247 18.1.2.4 Sub-Area 2440 – Support Services – Air Compressed air will be provided at the HV Workshop and HV Tire Change facilities via suitably sized standalone air compressors and receivers. 18.1.2.5 Sub-Area 2450 – Support Services – Power Power will be provided to the Mines Support Facilities via a connection from the 33 kV overhead power line running past the site into a kiosk substation. From the kiosk, 400V/230V power will be reticulated to all required buildings and services in common services trenches. 18.1.2.6 Sub-Area 2450 – Support Services – Communications Communications will be provided to the Mine Support Facilities from the Process Plant Area via a fiber optic cable in the overhead power lines and will terminate into a server room within the Mine Offices. Cat 6 cables will be reticulated to required building and services. 18.2 Facility 4000 – Project Services This section details the supply and distribution of services outside the process plant. 18.2.1 Area 4100 – Water Supply Area 4100 covers the water supply to the process plant and between facilities. 18.2.1.1 Sub-Area 4110 – Water Treatment Plant (WTP) A Water Treatment Plant will be fed with a combination of decant return, runoff pond water and pit dewatering discharge at a nominal rate of 500 m³/hr. 18.2.1.2 Sub-Area 4120 – Raw Water The raw water requirement will be approximately 30,000 m3/day, fluctuating due to current operations and weather. The existing line from the Raw Water Dam will be supplemented with an additional 250 mm poly line approximately 4 km in length in order to handle the increased raw water requirements of the higher throughput. This would run parallel to the existing 400 mm poly line. Raw water will be supplied to the mine support facilities via a one km supply line to a storage tank in that facility. Raw water will be supplied to the power plant via a two km supply line and to the construction camp via a 5 km supply line. Supply of water to the construction camp via tanker was investigated and it was deemed that a supply pipeline was the most cost-efficient method for transferring water to the construction camp. 18.2.1.3 Sub-Area 4130 – Potable Water Potable water will be produced by a Potable Water Treatment Plant within the processing facility, and will be distributed to the process plant, construction camp, residual operating camp, mining, administration offices and laboratory facilities. There will be nominally 100 m3 of potable water consumed per day.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 248 18.2.2 Area 4200 – Power Supply 18.2.2.1 Sub-Area 4210 – Power Generation Refer to Section 18.8 – Electric Power Plant for the discussion on power supply design. 18.2.2.2 Sub-Area 4230 – High Voltage Electrical Distribution A Main 33kV Switchroom will be the main point of connection for incoming power from the Power Station, as well as fiber optic communications between Telstra and the plant. The Switchroom includes the main plant 33 kV switchgear feeders, metering, and an allowance for process plant power quality equipment. 33 kV power distribution is via the Main 33 kV Switchroom, which will feed 33 kV buried cables supplying the Process Plant 33 kV Substations, as well as the site wide overhead power line. 18.2.2.3 Sub-Area 4231 – Power Distribution It is not desirable to install overhead power lines close to the Process Plant, where it may cause a hazard to over-height vehicular traffic such as cranes. Therefore, in order to keep the overhead power lines away from these areas, 33 kV power to and from the Process Plant will be connected by buried cables. The buried cables will be connected to the Main 33 kV Switchroom. 18.2.2.4 Sub-Area 4232 – Overhead Power Lines 33 kV power will be provided from the Power Station via a single feeder. New 33 kV overhead power lines will be required to connect the Power Station to the Process Plant, which are approximately 1.2 km apart. These will be installed along a similar route as the main access road. The 33 kV power line will also need to be distributed around site to the following facilities: „ ANFO Facility „ Heap Leach Pad (existing) „ Construction Camp/Residual Accommodation Camp „ Waste Water Treatment Plant (WWTP) „ Pit Dewatering „ Mine Services „ Site Radio Communication Tower (depending on final location) „ Gatehouse „ Future Tailings Storage/Decant The total length of overhead power line required to reach the Process Plant and the above locations from the Power Station is 7.1 km. The overhead power line will incorporate a fiber optic cable into the earth conductor. Overhead power lines will be suitably rated for a high dust and lightning strike region. The Accommodation Camp is assumed to be within 2 km of either the existing 22 kV power lines or the new site 33 kV power lines.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 249 18.2.3 Area 4300 – Communications 18.2.3.1 Sub-Area 4310 – Fiber Optic Two fiber optic cable ring mains will be installed around the Process Plant to form redundant topology. These cables will generally be installed on cable ladders within the plant, although sections of the cable will be buried where cable ladder access is not available. The second cable is to provide redundancy within the Process Plant in case of damage to the first cable and will follow a separate route where this is practical. The plant fiber optic cables will contain up to 72 cores and will incorporate separate networks for data communications including those for the Plant Process Control System, the site IT system, a site Voice over Internet Protocol (VoIP) phone system, site Closed Circuit TV (CCTV) and security network, and fire detection system. Outside of the Process Plant, the fiber optic cables will be incorporated into the earth conductor of the overhead power lines. Optical Ground Wire (OPGW) is a dual functioning cable. It is designed to replace traditional earth wires on overhead power lines with the added benefit of containing optical fiber cores that can be used for communications purposes. These will connect communications equipment from locations such as the Power Station, Water Treatment Plant, Gatehouse and ANFO Facility to the plant communications network. A communications hut will be provided (by others) outside the gatehouse. A fiber optic cable will be installed underground between this communications hut and the site overhead power line network at the first overhead power line pole from the Power Station. As it utilizes the OPGW, the fiber optic cable between the Telstra Hut and Process Plant will not have a second redundant cable, although some redundancy will be provided by using additional fiber cores in the OPGW. Redundancy requirements will be investigated and implemented during the detail design stage. 18.2.3.2 Sub-Area 4311 – Phones Telephone communications will be via digital VoIP technology. This allows telephone calls to be made over an Internet Protocol (IP) network rather than through a separate copper network. Calls can traverse the company’s Information Technology (IT) network or an external portal. 18.2.3.3 Sub-Area 4312 – Radios Refer to Section 18.3.5 – Area 5800 – Communications. 18.2.3.4 Sub-Area 4313 – Telemetry A Radio Telemetry System will be used to communicate to remote locations that require data exchange between the Process Plant and the remote location. Radio Telemetry will be provided to communicate with the decant water return pump station, ANFO Facility and pit dewatering pump station. The system will incorporate a Master Telemetry Station, located in a switchroom of the Process Plant, and a number of remote Telemetry Stations, located in remote equipment switchboards. The Master Telemetry Station will communicate with the Plant Process Control System via the preferred communications network and will communicate with the remote locations via radio. Suitable antennas will be installed at each location.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 250 Control of the remote equipment will be made by the Plant Process Control System, with sufficient data exchange to ensure correct operation of the remote equipment. 18.2.4 Area 4400 – Tailings Dam A total of 202 Mt of process tailings will be stored in two separate tailings storage facilities (TSFs) over a design operating life of 13 years at a nominal ore processing rate of 50,000 tpd. The starter embankments for the existing TSF 1 were constructed during active mining operations between 1996 and 2000. A total of approximately 9 Mt of ore was processed during this period (MWH, 2006). Approximately 87 Mt of additional tailings will be stored in the existing TSF 1 through staged raises of the existing facility constructed using a combination of centerline and upstream construction techniques. TSF 2 will be constructed east of the Process Plant and raised in stages using upstream construction techniques. A total of approximately 114 Mt of tailings will be deposited in TSF 2. The embankments for TSF 1 and TSF 2 will be constructed using non- acid generating waste rock from the open pit operations. Table 18-1: 50 ktpd TSF 1 and TSF 2 Parameters TSF 1 Design Parameter Value TSF 1 EXPANSION Design Tailings Storage Capacity 87.4 million tonnes Average Tailings Dry Density 1.5 t/m3 Design Life 12 years TSF 2 Design Tailings Storage Capacity 114.7 Mt Average Tailings Dry Density 1.5 t/m3 Design Life 13 years The design storage capabilities for TSF 1 and TSF 2 were based on an assumed average in-place dry density of 1.5 t/m3. Conventional thickened slurry tailings will be pumped to the TSFs at a nominal rate of 50,000 tpd. Tailings will be deposited within the TSF using subaerial deposition techniques through multiple spigot points along the perimeter embankment crest of the TSF. The existing TSF 1 is a side-hill type conventional slurry tailings storage with perimeter embankments constructed using mine waste and select borrow materials. The existing TSF 1 embankment is referred to as the Stage 1 embankment. The existing facility incorporates an extensive underdrainage system and decant towers with gravity drainage pipes that penetrate the perimeter embankment and connect to an external water collection pond. The existing embankment will be initially raised by the centerline method using mine waste and select borrow material. This approach provides for a robust platform for future raising construction. Subsequent embankment raises will be constructed using mine waste and upstream methods. The TSF 1 raises will be constructed in an alternating sequence with construction of TSF 2 starter and raises. This alternating sequence was adopted to provide adequate time for tailings consolidation and strength gain to permit upstream raising construction. The installation of wick drains in the foundation of each tailings raise is planned to improve the tailings consolidation rate, reduce risks associated with upstream embankment raising construction, and improve water recovery from the deposited tailings.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 251 The TSF 2 starter embankment will be constructed using mine waste and select borrow material after the TSF 1 Stage 2 raise is completed and operational. The TSF 2 embankment will be raised by upstream methods and using mine waste. TSF 2 raises will be constructed in an alternating sequence with construction of TSF 1 raises. Similar to TSF 1, this alternating sequence was adopted to provide adequate time for tailings consolidation and strength gain to permit upstream raising construction. The installation of wick drains in the foundation of each tailings raise is planned to improve the tailings consolidation rate, reduce risks associated with upstream embankment raising construction, and improve water recovery from the deposited tailings. 18.2.5 Area 4500 – Waste Disposal Sewage waste disposal will be via a Waste Water Treatment Plant (WWTP) installed at the Process Plant Area. The Mine Support and Process Plant buildings will be connected to the WWTP via the sewer pipework reticulation system. 18.2.6 Area 4600 – Plant Mobile Equipment The plant mobile equipment to be purchased for the process plant will be as follows: Table 18-2: Mobile Equipment for Process Plant Light Vehicles Quantity Landcruiser wagon 2 Dual cab Ute 11 Tray top Ute 9 Troop carrier (ambulance) 1 Bus/troop carrier (15 seater) 1 Coach 3 Subtotal 27 Loader – Cat 966G Allowed for in mining Tool Carrier – Cat IT28 1 Bob Cat – Mustang Case 1 Crane – 15t Franna 1 Hiab Truck – 7t 1 Service Truck – 2t 1 2t Forklift – allowance 2 25t Container Forklift 1 80t Crane 1 Subtotal 9

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 252 18.3 Facility 5000 – Project Infrastructure This section provides a description of the Project infrastructure required for the construction and operation of the process plant. 18.3.1 Area 5100 – Site Preparation Bulk earthworks for the Process Plant will be designed to minimize the import of fill material. Where fill material is required to be imported, material from the existing RoM Pad ramp and from the existing stockpile located adjacent to the Tollis and Golf Pits will be utilized. The site will be prepared such that there is a mono slope fall from the proposed boundary of the pit toward the existing drainage channel on the east side of the proposed process plant. To minimize the extent of stormwater run-off across the plant site, cut-off drainage channels will be installed to divert stormwater run- off around the plant. This will also minimize underground drainage and depth of open channels required on the plant site. A settling pond will be located north of the stockpile and is designed to minimize solids overflowing into the drainage channel. Stormwater channels will be designed to collect water alongside the unsealed plant roads and direct them beneath the roads via corrugated steel culverts to prevent scouring of plant roads. All stormwater run-off will be directed toward the existing drainage channel on the east side of the proposed process plant. Rip-rap protection to earthwork embankments adjacent to the existing drainage channel on the east side of the proposed process plant will also be installed for flood protection. 18.3.2 Area 5200 – Support Buildings The Support Buildings consist of the building infrastructure for the Process Plant. The support building sizes and number of operations personnel has been developed. 18.3.2.1 Sub-Area 5210 – Administration Offices The Administration Offices will be complexed with multiple transportable buildings and used by plant management and administration personnel and is located at the northern end of the Process Site. The building will include necessary system furniture and provide cellular and open planned offices along with conference and meeting spaces. The footprint of the Administration Offices is approximately 14.4 m by 29.7 m and will be sized to accommodate 30 people. 18.3.2.2 Sub-Area 5211 – Process Plant Offices The Process Plant Offices will be complexed with multiple transportable buildings located within the existing Flotation building. The buildings will include the necessary system furniture and provide cellular and open planned offices. The Process Plant Offices will be sized to accommodate 17 people per shift.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 253 18.3.2.3 Sub-Area 5220 – Workshop / Warehouse The Workshop / Warehouse will be incorporated into the existing Flotation Building along with the Process Plant Offices, Main Control Room, Crib and Ablutions and the Light Vehicle Workshop. The Offices / Ablutions / Crib facilities will be transportable building located within the annex of the building. The existing Flotation building will require modifications to steelwork and replacement of the concrete floors. The building will be complete with services including overhead traveling crane, power, lighting, communications, compressed air, water, specialist equipment and other services necessary for the maintenance of process plant equipment and the LV fleet. The Workshop / Warehouse will be sized to accommodate 25 people per shift. 18.3.2.4 Sub-Area 5230 – Reagent Store The Reagent Store will consist of one Dome Shelter mounted on sea containers with a concrete floor. The reagent store will be sized approximately 16.7 m by 24.4 m, which includes four sea containers that will act as additional space for the storage of reagents. The Reagent Store will be complete with all services including power and lighting. The Dome Shelter will be constructed of steel frame and tensile fabric with a fabric life expectancy of 10 years. The Reagent Yard will cover an area of 1,750 m2 and contain a secured fenced hardstand area for the storage of sea containers used at the Reagent Store. 18.3.2.5 Sub-Area 5240 – Crib / Ablutions The Crib / Ablutions facilities will be complexed with transportable buildings located within the existing Flotation Building. The buildings will include the necessary system furniture fixtures and fittings and will be suitable for operations and periodic shutdown personnel. 18.3.2.6 Sub-Area 5250 – Emergency Services The Emergency Services Facilities will be a transportable building used by the First Aid and Fire and Emergency Services personnel. It will be located adjacent to the Administration Offices in the Process Plant and will be sized 14.4 m by 9.9 m. This area will include an undercover area for an ambulance bay and an area for additional services. 18.3.2.7 Sub-Area 5255 – Helipad An allowance has been made for a bitumen helipad to be located close to the Process Plant. The helipad landing zone will be in a fenced-off enclosure and contain a wind sock. The helipad location is not confirmed at this stage. 18.3.2.8 Sub-Area 5260 – Sample Preparation and Laboratory The Sample Preparation and Laboratory facility will be a structural steel shed with insulated metal clad walls and roof and concrete floor for the receipt and storage of samples and a transportable building containing the preparation areas, laboratory and offices for processing samples. The Sample Preparation and Laboratory

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 254 building and equipment has been sized to process 450 samples/day. Sampling will be taken from various points throughout the process plant. Samples will be assayed for composition and gold loading. 18.3.2.9 Sub-Area 5270 – Gatehouse / Security The Gatehouse / Security Facilities will be a single transportable building used by security personnel for recording movement to and from the Site and drug and alcohol testing of contractors and employees. The facility will include a boom gate, pedestrian turnstile and swipe card access. The Gatehouse will be located along the access road to the Process Plant. 18.3.2.10 Sub-Area 5280 – Control Building – Crushing The Crushing Control Room will be a single transportable building located at the Primary Crusher. The buildings will include the necessary system furniture for one operator. 18.3.2.11 Sub-Area 5281 – Control Building – Main Control Building The Main Control Room will be a single transportable building located within the Flotation Building. The building will be sized 11 m by 3 m and include the necessary system furniture for one supervisor and three operators. 18.3.2.12 Sub-Area 5282 – Control Building – CIP The CIP Control Room will be a single transportable building located on top of the Leach Tanks and subdivided into a Control Room and a Titration Room. The building will be sized 9.6 m by 3 m and include the necessary system furniture for one supervisor and two operators. 18.3.2.13 Area 5300 – Access Roads, Parking and Laydown The existing Plant Access Road is suitable for use. Miscellaneous road repairs will be to the existing Plant Access Road. The existing Process Plant Retention Pond corrugated steel culvert crossing the drainage channel on the east side of the proposed Process Plant is suffering from corrosion. These corrugated steel culverts will be replaced.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 255 18.3.3 Area 5400 – Heavy Lift Cranage Heavy lift cranage covers the cranage that will be needed on site during the construction period for the heavy lifts on site, approximated as follows: Table 18-3: Heavy Lift Cranage Requirements Crane Duration (Hours Per Year) 600 t 270 450 t 470 200 t 540 180 t 540 100 t 810 80 t 3090 50 t 1610 18.3.4 Area 5600 – Bulk Transport Bulk transport in and out of site will be weighed on a weighbridge near the gatehouse. The weighbridge will be located on a dedicated off take from the main road. The site weighbridge will be capable of weighing a triple trailer tanker or truck. 18.3.5 Area 5800 – Communications 18.3.5.1 Sub-Area 5810 – Site-wide Radio Communications The site will require radio communication for both individual division usage and also across all site personnel for emergencies. Some divisional usage will be localized, but coverage across the site will generally be required. To cover all radio communications requirements across the site, there will be a suitably located, approximately 50 m tall, communications tower complete with appropriate antenna arrays and ancillary equipment. A communication hut will be located at the base of the tower. This hut will house the repeaters, servers, communications equipment and back-up batteries to provide a robust radio communications system. A maximum of eight individual radio channels will be provided. Depending on the final location, the communications hut will either be connected to the overhead power line network or, in the case where this is not practicable, a solar powered power supply will be provided. The communication hut back-up battery life will last for a minimum of 10 hours on loss of incoming power. The radio system will include the following radio quantities for individual personnel and vehicle usage: „ 320 hand held radios and spare batteries „ 50 mobile (vehicle) radios complete with battery charger, remote speaker/microphone and antennas

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 256 „ 10 base station radios complete with battery charger, remote speaker/microphone and antennas „ 50 multi-bay chargers for portable radios. 18.4 Facility 6000 – Permanent Accommodation Permanent accommodation for plant operating staff will be in the town of Katherine at the discretion of operators. A portion of the camp will remain after the construction period for temporary accommodation for staff, fly-in maintenance teams and shutdown personnel. Refer to Section 18.5.1 – Area 7300 – Construction Camp for the permanent camp details. 18.4.1 Area 6100 – Personnel Transport A bus transit area consisting of three bus shelters will be constructed in the town of Katherine for transport of operators to and from site. This is to ensure staff will not be driving from the Mt Todd mine site to Katherine after 12-hour shifts. 18.5 Facility 7000 – Site Establishment and Early Works The site establishment will occur prior to the operation of the Construction Camp with the hire / purchase of EPCM Contractor and Client Offices / Crib / Ablutions for the duration of the project. The facilities will be located at the Process Plant Area. The early works will require a ‘Fly Camp’ for bulk earthworks and services Contractors. This accommodation has been allowed for at the town of Katherine for 40 people for three months to complete the early work at the Construction Camp Facilities and Process Plant Area. 18.5.1 Area 7300 – Construction Camp The Construction Camp will be sized for 390 construction workers based on the manning histogram developed for the Project. The Construction Camp will be located approximately 2 km from the access road. The final location of the camp will be determined during the Feasibility Study. The Construction Camp will be hired for the 24-month construction duration with the exception of 60 rooms which will be purchased from the outset. Bulk earthworks and all services including power, communications, water and sewerage will be completed prior to the arrival of the hire buildings. The accommodation village will consist of the following building and services: „ 390 rooms certified in accordance with the Building Code of Australia „ First Aid „ Laundry Buildings „ Male / Female Ablutions „ Dry Mess including Kitchen / Dining / Crib Facilities „ Wet Mess „ Ice Rooms „ Administration Building „ Covered Outdoor Area

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 257 „ Gymnasium Building „ Power Supply and Distribution „ Communications Nodes and Distribution „ Potable Water and Reticulation „ Fire Services „ Organic Materials Waste Dump „ Waste Water Treatment Plant „ LV Parking Area and Bus Drop Off / Pick Up „ Unsealed Access Road 18.6 Facility 8000 – Management, Engineering, EPCM Services Facility 8000 will cover the indirect costs associated with the management of the project from detailed design through to handover to operations. Included within this section will be the EPCM team, external consultants, commissioning team, owner’s team and any costs for licenses, fees, legal costs and insurances. 18.6.1 Area 8100 – EPCM Services This area includes the costs for engaging the services of one or more contractors to perform the engineering, procurement and construction management for the project. The costs in this area have been derived by way of a bottom-up estimate. 18.6.2 Area 8200 – External Consultants/Testing This area is a Prime Cost (PC) Sum that allows for the engagement of any environmental, Human Resources/Industry Relations or Health, Safety, Environment and Community (HSEC) consultants that might be required through the execution phase of the project. 18.6.3 Area 8300 – Commissioning Area 8300 is concerned with the costs for the management and engineering associated with commissioning and was derived, for the Process Plant, as 3% of the total mechanical equipment supply costs. 18.6.4 Area 8400 – Owners Engineering/Management Area 8400 contains costs associated with the owner’s team located either on site and or in the project office. 18.6.5 Area 8800 – License, Fees and Legal Costs This area contains a PC Sum for the costs of licenses, fees and legal costs that would need to be expended throughout the execution phase of the project. Additional costs to this area may need to be incorporated by Vista based on information that is not yet known.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 258 18.6.6 Area 8900 – Project Insurances Project insurances are a PC Sum included to allow Vista to take out any insurances that are deemed necessary to ensure project success. The amount of funds to be included in this area will be dependent on Vista’s criteria for an acceptable risk profile and, as such, is subject to interpretation by Vista. 18.7 Facility 9000 – Preproduction Costs Facility 9000 will cover the indirect costs associated with direct labor during commissioning, the purchase of spare equipment and replacement of equipment damaged during commissioning. Areas 9600 to 9900 are sums of money associated with working capital, corporate reserves, escalation and exchange rate fluctuation, contingency and management reserve. 18.7.1 Area 9100 – Preproduction Labor Preproduction labor covers the costs that are not part of Construction Contracts, not part of Commissioning, not part of post-handover operating ramp up costs but are for costs that may arise prior to operations taking over the Project in an operating context. This area is proposed for minor plant modifications and additions deemed necessary to achieve Project handover status. 18.7.2 Area 9200 – Commissioning Expenses Commissioning expenses is intended to cover the power, materials, labor and spare parts that are associated with making plant modifications, additions and operations during the commissioning period. 18.7.3 Area 9300 – Capital Spares Capital spares are all spares which are non-consumables. These are large items that are not expected to be used; however, these items must be kept in spare for the project due to long lead times, high cost and process importance. These items include, but are not limited to, spare mill motors, HPGR motors, HPGR rolls, intertank screens, conveyor drives, pulleys and belts. 18.7.4 Area 9400 – Stores and Inventories Stores and Inventories allows for a first fill of the primary warehouse for smaller items that are replaced frequently, including but not limited to valves, flanges, pipe fittings, pulleys and ‘V’ belts. 18.7.5 Area 9600 – Working Capital and Finance Working Capital and Finance will be an allowance for a sum of money to be left for use after the plant is operational before the revenue stream is stable. Costs for this have not been included by Proteus, as this provision has been included by Vista in the Technical Economic Model. Project working capital provides for estimated normal timing delays associated with receipts and disbursements of cash, with such amounts being fully recovered by the end of the project life. An additional non-recovered working capital amount provides for final owner’s closeout expenditures.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 259 A corporate reserve will be required to support, if necessary, Project operations after the plant is operational but before revenues are sufficient to generate positive and stable cash flows. No corporate reserve was included in the estimate as this provision will be made by Vista. 18.7.6 Area 9700 – Escalation and Foreign Currency Exchange Escalation and Foreign Currency Exchange allowances will be necessary to cover potential inflation and fluctuation of foreign currencies from the date of this study until actual transaction dates. Such allowances have not been included in the estimate as provision for this will be made by Vista. 18.7.7 Area 9800 – Contingency Provision The contingency provision covers those items within the scope that are known to exist but have not yet be defined. Contingencies are estimated on a line item by line item bases in the TEM. 18.7.8 Area 9900 – Management Reserve Provision The management reserve provision is a measure of the accuracy of this cost estimate and is a portion of additional money that would not be available to the project manager but will be held in reserve by Vista to cover unforeseeable and uncontrollable events including, but not limited to: strikes, unusual weather conditions, premium payments arising from accelerated construction programs to recover lost time. A reserve for such potential costs has not been included in the estimate as provision for this will be made by Vista. 18.8 Electric Power Plant The mine’s electrical power demands are estimated to be approximately 70 MW based upon the load list dated November 27, 2017. Electrical demand will be met through the installation of seven Jenbacher J920 reciprocating gas engines to meet the power demand. Water consumption in this power plant arrangement is very small and primarily for makeup of the closed loop engine cooling system and general housekeeping washdown. It is estimated that intermittent water use will be up to 11.5m3/hr (50 gpm). Two potential locations are considered for the location of the power station. Option 1 is locating the power station near the entrance to the mine and includes connection to the existing natural gas pipeline spur with the shortest powerline connection to the mine. This pipeline spur requires a tolling fee of AUD0.60 per gigajoule (GJ) of gas bringing the wholesale price to AUD7.00 per GJ. Near the main gas transmission pipeline is an alternate Option 2 location for the power station that will avoid the tolling fee for the spur pipeline but requires the upgrade of the 10 km electrical powerlines with new conductors and as well as new towers designed to carry the additional weight of conductors rated for a higher megavolt-ampere (MVA) class. The Option 2 location will also require additional infrastructure for non- potable service water and fire protection, which would entail a non-potable service/fire water storage tank, firewater pumps, and non-potable service water pumps.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 260 Figure 18-1: Power Station Location

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 261 The plant required net output is the mine’s required electrical demand plus the power stations auxiliary loads and is based on the preferred generation technology. Table 18-4: Power Station Location Budgetary Comparison Mine Output Value Generator Manufacturer GE-Jenbacher Model J920 (7) Plant Required Net Output 69.6 MW Estimated Fuel Demand (GJ/yr) 5,253,349 For the purpose of this Preliminary Feasibility Study, the Option 1 location will be carried forward. 18.8.1 Generation Option Selection The QP [Anthony Clark, P.E.] performed an evaluation of generation options based upon providing reliable power for a steady load demand with minimum onsite personnel requirements and low life cycle operating costs. The evaluation has concluded that natural gas-fueled reciprocating engines provide the most economical and reliable means of power generation at the mine site. The QP recommends that the electrical demand be met with seven reciprocating engines with backup power being provided by the electric utility grid. Gas reciprocating engines will provide excellent reliability, increased operational flexibility and redundancy required by the Project. If startup loads exceed the capacity of the initial engines, the utility grid connection is available for supplemental power. The technology configuration for this study uses the General Electric Jenbacher J920 engine but there are a number of commercially available gas engine models in the 10MW range with operating plants in-country to provide a technically sound field to select a reliable equipment supplier with competitive pricing and local technical support. 18.8.2 Mt Todd Electrical 18.8.2.1 Conceptual Design A conceptual electrical one-line diagram, Figure 18-2, has been created to show the electrical distribution system from the 33kV utility interconnect down to the 400V power distribution bus. The equipment ratings are preliminary and based on generator ratings provided by Jenbacher and budgetary quotes for the balance of plant equipment. The equipment ratings shown are for cost estimating purposes only. The actual equipment ratings will be determined using detailed load flow and short circuit studies during detailed design. 18.8.2.2 Plant Arrangement The auxiliary electrical equipment is included on the mechanical general arrangement drawing (Figure 18-3). All the equipment physical sizes are based upon similar equipment from reference projects.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 262 18.8.2.3 Step Load Capability Reciprocating engine generators are designed for fast startup times, fast ramp rates and flexibility. For best performance when starting and fast ramp times, the engine must be pre-heated or operating at low loads with the cooling water at 55°C (by onboard electric heater) to avoid engine damage. A single 10 megawatt (MW) engine can accelerate from start to 100% load in 5 minutes with ramp up as fast as 100 kilowatts per second (kW/sec). If a large motor at the mine is brought online, the starting load can be spread across all engines in the power station for a ramp rate as high as 700 kW/sec with the connection to the electric utility grid available for supplementary starting support.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 263 Figure 18-2: Conceptual Electrical Line Diagram

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 264 Figure 18-3: General Plant Arrangement

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 265 19.0 MARKET STUDIES AND CONTRACTS 19.1 Markets Gold metal markets are mature, with many reputable refiners and brokers located throughout the world. The advantage of gold, like other precious metals, is that virtually all production can be sold in the market. As such, market studies, and entry strategies are not required. Metallurgical process studies confirm that the Project will produce doré of a specification comparable with existing operating mines. Demand is presently high with prices showing remarkable increases during recent times. The 36-month average London PM gold price fix through August 31, 2019 was US$1,279/oz. 19.2 Contracts Currently, there are no contracts in place for development and operations. However, Vista has obtained budgetary quotes, as is common for PFS level studies, for future materials and service needs. The following contracts are expected to be in place upon project commencement: „ Secure doré transportation to refinery; „ Doré refining; „ Supplier and service contracts including; ⎯ EPCM; ⎯ Equipment supply; ⎯ D&C; ⎯ Diesel and fuel oil; ⎯ Natural gas for the power plant; ⎯ Process reagents; ⎯ Equipment preventive maintenance and repair (MARC) services; ⎯ Site security services; and ⎯ Camp management, catering and support services.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 266 20.0 ENVIRONMENTAL STUDIES, PERMITTING, AND SOCIAL OR COMMUNITY IMPACT This section discusses the environmental permitting and social impact aspects of the Project. The EIS was submitted in June 2013. The Northern Territory Environmental Protection Authority (NTEPA), as the responsible government authority to advise on the environmental impact of development proposals, provided its final assessment of the Project in September 2014. In January 2018, the “authorization of a controlled activity” was received for the Project as required under the Australian Environmental Protection and Biodiversity Conservation Act of 1999 (EBPC) as it relates to the Gouldian Finch, and as such has received approval from the Australian Commonwealth Department of Environment and Energy. In November 2018 the “Mine Management Plan” (MMP) was submitted to the Northern Territory Government Department of Primary Industry and Resources (DPIR). This is the last approval required before works can occur. The approval of the MMP will result in the “Mining Authority” being issued. 20.1 Environmental Studies A number of environmental studies have been conducted at the Project in support of development of EISs and as required for environmental and operational permits. Studies conducted have investigated soils, climate and meteorology, geology, geochemistry, biological resources, cultural and anthropological sites, socio-economics, hydrogeology, and water quality. The Mt Todd Project Environmental Impact Statement (EIS) submitted June 28, 2013 to the Northern Territory Environment Protection Authority (NTEPA), approved in September 2014, provides an understanding of the existing environmental conditions and an assessment of the environmental impact of the Project. Key issues of concern regarding the Project impacts that were addressed in the EIS include: „ Acid and metalliferous drainage (AMD) seepage and runoff from the waste rock dump, ore stockpiles and tailings storage facilities potentially contaminating surface and ground waters continuing long after the mine has ceased operation; „ Potential contamination of surface water from AMD causing adverse impacts on downstream water quality, aquatic environment and downstream users; „ Management and treatment of a large quantity of acidic and metal laden water currently existing on the site; „ The proposed WRD covers an approximate area of 217ha with an estimated height of 160m. Final design of the WRD must ensure the structure is safe, stable, not prone to significant erosion, minimizes AMD seepage and runoff and meets stakeholder expectations as a final land use structure; „ Biodiversity impacts, including matters of environmental significance, associated with disturbance footprint of mining activities and infrastructure requirements; „ The challenges of successful mine closure and rehabilitation; and „ Potential social, economic, transport and heritage impacts.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 267 The Project is located in the Pine Creek Bioregion and part of the Yinberrie Hills Site of Conservation Significance (SOCS30). Each of these potential impacts were assessed and mitigation or management measures were outlined in the EIS. 20.1.1 Flora and Vegetation Eight vegetation types covering 5,462.56ha were mapped in the Mineral Leases. Eucalyptus tectifica, E. latifolia, E. tintinnans, E. spp. Woodland; E. phoenicea, Corymbia latifolia low woodland – woodland (scattered E. tintinnans); and C. dichromophloia, E. tintinnans, Erythrophleum chlorostachys Woodland covers 80% of the site. The Project is not expected to significantly impact vegetation in the area. Eight-hundred and forty species of flora are known to occur within 10km of the leases. The 2011/12 surveys identified 226 taxa, of which 67 were not recorded from previous surveys. The total number of species known from the area is 959. The only threatened plant species recorded from the area is the bladderwort, Utricularia singeriana. This species is listed as Vulnerable under the Territory Parks and Wildlife Conservation (TPWC) Act 2000. The closest known record is 6 km west of the Mineral Leases. The Project is not expected to have an impact on any threatened flora. 20.1.2 Nationally Threatened Fauna Threatened fauna species are those that are listed as threatened (or a related category) under the Commonwealth EPBC Act and/or Northern Territory’s TPWC Act. Eighteen threatened fauna species that do or could occur within the mine site include: „ Six mammals; „ Eight birds; „ Three reptiles; and „ One fish. Six of the eighteen threatened species have recorded in the mine site during field assessments. 20.1.3 Migratory and / or Marine Species Fourteen EPBC Act listed migratory bird species potentially occur within 10km of the project area. Ten have been recorded from the leases. Seven EPBC listed marine species potentially occur with 10km of the project area. This includes six bird species and one reptile species. The freshwater crocodile was recorded in the leases. None of the listed marine species is likely to have a high risk of impact from the proposed development. 20.1.4 National Heritage Places The Yinberrie Hills is a Site of Conservation Significance and was placed on the Interim Register of the National Estate for its natural values. However in 2007 the Register of the National Estate was declared no longer a statutory list. Surveys located 20 archaeological sites. The most significant was Mt Todd 26 – an extensive greywacke quarry, extraction and reduction site, one of the largest recorded in the Northern Territory. The remainder were lithic scatters or quarry and reduction sites with low to medium heritage significance.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 268 With respect to Jawoyn Resource Knowledge, 62 animal, 63 plant and one fungal taxa were identified and the associated Jawoyn knowledge recorded. Amongst the Jawoyn, the mine site is not considered a notably productive environment. Plants and animals encountered and discussed during the ecological knowledge consultation are widespread and not unique to the mine site. Vista employs Jawoyn Rangers for reviewing and potentially clearing any heritage sites prior to disturbance. 20.2 Waste and Tailings Disposal, Site Monitoring and Water Management 20.2.1 Waste Rock Disposal Waste rock will be disposed of in a WRD constructed as an expansion of the existing WRD. All waste rock will be analyzed to identify the rock as potentially acid generating (PAG) or non-PAG material before being hauled to the WRD. Non-PAG material will be stockpiled for use in reclamation covers or placed in the WRD. Construction of the WRD is described in Section 16.0 – Mining Methods. Reclamation and closure of the WRD is described in Section 20.5 – Mine Reclamation and Closure. 20.2.2 Tailings Disposal Tailings will be disposed of in two tailings storage facilities, TSF 1 and TSF 2. TSF 1, an existing tailings storage facility, will be expanded with eight additional raises to the embankment and construction of two new saddle dams at the west end of the impoundment. A second tailings storage facility, TSF 2, is to be constructed after re-commissioning of TSF 1. The engineered containment system for the TSF 2 impoundment includes a 60-mil linear low-density polyethylene (LLDPE) textured (double sided) liner and a tailings overdrainage collection network to mitigate the risk of seepage. Tailings decant water and water collected in the TSF seepage interception network will be treated in the water treatment plant or used for the process plant. Construction of the tailings storage facilities is described in Section 18.2 – Facility 4000 – Project Services. Reclamation and closure of the TSFs is described in Section 20.5 – Mine Reclamation and Closure. 20.2.3 Site Monitoring Currently, surface water monitoring is conducted at various locations at the site. A comprehensive site monitoring plan has been incorporated into the MMP. 20.2.4 Water Management The primary existing environmental issue at the site is water management resulting from the project shutdown without implementation of closure or reclamation activities. The pit and existing water RPs (excluding the raw water pond) contain acidic water with elevated concentrations of regulated constituents. This water has been managed through evaporation, pumping to the Batman Pit for containment, micronized lime treatment of the pit lake, and controlled discharge of treated water to the Edith River in accordance with the approved WDL. Historically, wet season rainfall resulted in short-term uncontrolled overflow from retention ponds to the Edith River due to the high amount of precipitation received in short periods of time coupled with insufficient pumping capabilities. Current water management strategies employed by Vista appear to be successful at preventing recurrence of historic uncontrolled discharges and are minimizing impacts on the Edith River downstream of the Project Site.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 269 Prior to, during, and following resumed mining operations, water management at the site involves distinct water management components including in-pit treatment, seepage management, treatment of acid rock drainage and metal laden leachates (ARD/ML), and surface water management. Each of these components is discussed in the subsections below: 20.2.4.1 In-situ Pit Treatment In-situ treatment of the Batman Pit (RP3) was conducted by use of limestone and quicklime. Treatment has been undertaken to produce water to be discharge at rates protective of water quality in the Edith River in a suitable timeframe to meet project requirements. The treatment methodology included raising the pH of the water within the pit lake to greater than pH 8.0 using limestone and quicklime in succession to capitalize on the capabilities of the low-cost limestone and minimize the quantity of quicklime required to attain a pH sufficient to precipitate additional metals. Raising the pH to greater than 8.0 will result in the precipitation of key metals of concern including iron, aluminum, chromium, copper, lead, nickel, cadmium, cobalt and zinc. On an ongoing basis, quicklime is used to buffer the pH as required on an annual basis. 20.2.4.2 Seepage Management A thorough assessment of the infiltration and seepage conditions of the WRD, HLP, TSF 1, ore stockpiles, and other site facilities has not been well characterized at the current time but will be foundational to developing the site water management plan. The infiltration and seepage assessment will be included in the comprehensive site environmental system model (hydrogeologic, geologic, seepage, and geochemical conceptual models) to understand the solute-transport processes at the site and possible impacts to the aquifer from mine operation. Numeric modeling will be used for the infiltration and seepage assessment. 20.2.4.3 Ongoing ARD/ML Water Treatment Water treatment for the project will involve active water treatment for ARD/ML. Active water treatment will occur prior to operations, as part of rehabilitation of the site necessary to restart mining, during mining operations, and for a period following cessation of operations. Passive water treatment will be conducted at the site following closure in addition to use of the active water treatment plant as required. Active water treatment at the site has been described in Section 24.0 – Other Relevant Data and Information. Passive water treatment will be conducted in four separate passive treatment systems which include (in total) one biochemical reactor (BCR), four aerobic polishing wetlands (APW) and three aeration/settling ponds (AP). The goals of the passive/semi-passive water treatment at Mt Todd are to: „ Eliminate or drastically curtail the costs and continual inputs (e.g. reagents, power, staff) required to operate and maintain the active WTP; „ Eliminate sludge disposal operations and maintenance associated with active water treatment; „ Collect, contain, and treat ARD/ML prior to effluent release year-round; and „ Ensure that treated ARD/ML complies with the WDL numeric water quality standards. The passive water treatment technology recommended for treatment of WRD seepage, which is predicted to be net-acidic ARD/ML, is primarily metal-sulfide and metal-hydroxide precipitation via sulfate-reduction and the concomitant rise in solution alkalinity. The passive water treatment technology recommended for treatment of seepage from the TSFs, which is predicted to be net-alkaline ML, is aeration (oxidation) in

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 270 aeration/settling ponds (Aps) to allow metals to precipitate and settle. Effluent from the APs will be further aerated and treated prior to release to the environment in aerobic polishing wetlands (APWs) where the concentration of dissolved metals should be further reduced through complexation to plant-derived organic substrate, and potentially, accumulation in plant tissue. The treatment capacity of the four separate passive water treatment systems range from 10 to 50 m3/hour, which should be adequate to treat the anticipated rate of seepage from the WRD and TSFs following closure. The quantity of seepage from the WRD and TSFs following closure was estimated by simply multiplying the predicted infiltration of daily precipitation through the proposed WRD and TSF closure covers by the ultimate two-dimensional surface area of each facility. Using stochastic precipitation developed in the water balance model from site and Katherine gage data statistics, 1000 simulations (realizations) of daily precipitation were calculated in GoldSim at the following probabilities: 0%, 1%, 5%, 15%, 25%, 35%, 45%, 50%, 55%, 65%, 75%, 85%, 95%, 99%, and 100%. The mean of these precipitation probabilities was then calculated to represent daily precipitation. To estimate the daily seepage rate from each facility the calculated mean daily precipitation was multiplied by the ultimate facility surface area and the estimated rate of infiltration through the closure cover. Estimating flows and water quality 20 years in the future is wrought with uncertainty. These and other uncertainties inherent to passive water treatment are magnified by changes in mine plans and changes in closure plans and designs, which occur during normal operations, as well as unpredictable circumstances such as changes in climatic conditions, unforeseen material characteristics, etc. Therefore, the estimates and recommendations provided at this time should be considered preliminary and design parameters such as: hydraulic retention time; biochemical oxygen demand removal rate; metals and metal-precipitates removal and settling rate; and reactive substrate type, quantities, depletion rate and permeability overtime must be checked and updated or entirely modified as the project progresses and more information becomes available. 20.2.4.4 Surface Water Management Surface water at the site is well-documented and its management has been the object of study by both Vista and the NT Government in recent years. Surface water management is described further in Section 24.4 – Surface Water Hydrology. 20.3 Permitting and Authorizations On January 1, 2007, Vista became the operator of the Project Site and accepted the obligation to operate, care for, and maintain the assets of the NT Government on the site. Vista developed an Environmental Management Plan (EMP) for the care and maintenance of the Mt Todd mine site in accordance with the provisions of the Mineral Leases 1070, 1071, 1127 and 31525 granted under the Mining Act. The EMP identified the environmental risks found at the Project Site at its then present state of operations and defined the actions for Vista to take to control, minimize, mitigate, and/or prevent environmental impacts originating at the Project Site. As part of the agreement, the NT Government acknowledged its commitment to rehabilitate the site and that Vista has no obligations for pre-existing conditions until it submits and receives approval of an MMP for resumption of mining operations.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 271 The Project requires approvals, permits and licenses for various components of the Project. Table 20-1 includes a list of approvals, permits, and licenses required for the project and their current status. Table 20-1: Mt Todd Permit Status Approval/ Permit/ License Current Status Approval/ Permit License Date Expiration Date Environmental Impact Statement The NT Environmental Protection Authority provided its final assessment of the Project in June 2014. Approved Sep. 2014 NA Mining Management Act (or Plan) Approval from NT Department of Mines & Energy Mine operating permit request has been submitted. The MMP submitted in November 2018 IS for 50kt/day operations. Prior to commencing mine operations NA Heritage Act permit to destroy or damage archeological sites and scatters/ Aboriginal Areas Protection Authority Clearances Authority Certificate Number 2011/15538 issued. This certificate defined restricted works areas and granted select clearances to allow for initial investigations. Additional clearances will be required for further investigations as well as prior to disturbance associated with mine development. Aboriginal Areas Protection Authority dated Jul. 31, 2012 NA Dangerous Goods Act (1988) permit for blasting activities Waiting on final mine plan NA NA Extractive Permit (under DME Guidelines) for development of borrow pits outside of approved mining areas Would be required for PGM or LPM borrow areas. Permit application not yet in progress pending final selection of borrow areas NA NA Waste Discharge License (under Section 74 of the Water Act 1992) for management of water discharge from the site WDL 178-6 licensing discharge of waste water into the Edith River from the Mt Todd mine site, granted with conditions Nov. 26, 2018 Nov. 30, 2020 Waste water treatment system permits under Public Health Act 1987 and Regulations May be required for the waste water treatment system for the construction and operations accommodation village. Permit application not yet in progress pending design and siting of accommodation village. NA NA Approval to Disturb Site of Conservation Significance (SOCS) Batman pit expansion will disturb SOCS as breeding / foraging habitat for the Gouldian finch, pending determination on EIS. Jan. 22, 2018 NA In addition, permits that are required to commence construction works will be obtained prior to any construction activity. 20.4 Social or Community Requirements The Jawoyn people have strong involvement in the planning for the future of the Project. Vista has a good relationship with the Jawoyn. Areas of aboriginal significance have been designated, and the mine plan has avoided development in these restricted works areas.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 272 Those parts of the JAAC agreement that are within the public domain are presented in this report; the remaining part of the agreement, which is confidential, is not presented in this Technical Report. 20.5 Mine Reclamation and Closure A reclamation plan for the Project was developed in support of the Technical Report for renewed mining operations. This reclamation plan evaluates the reclamation activities that will be conducted for the landforms planned as part of mining commencement. Reclamation plans and strategies for each major facility at Mt Todd are briefly summarized in Table 20-2. Table 20-2: Reclamation Approach Task Facility Batman Pit WRD HLP TSF 1&2 Impounded Surface TSF 1&2 Dams (Embankments) Process Plant and Pad LGOS 2 Mine Roads Surface of Facility at Cessation of Production Composed of Non-PAG Material X X Final Overall Slopes > 3H:1V* X X Final Overall Slopes < 3H:1V* X X X X X X Benches Created During Construction X X X Install minimum 1.0 m-Thick non-PAG Material X X Install 0.8 m-Thick Store and Release Cover X X X Install 0.2 m-Thick Plant Growth Medium (PGM) Cover X X X X X X Revegetate with Native Seed Mix X X X X X X Install geosynthetic liner (with under and overlayer of fines) X Install Erosion and Sediment Controls X X X X X X Construct Access Restriction Bund X Additional Remedial Measures (as necessary) X X X X X X X X * > and < indicates slopes are steeper and less steep, respectively. “X” denotes where the task or characteristic is applicable to the landform Costs associated with reclamation and closure are provided in Section 21.1.5. In accordance with regulatory requirements, a reclamation bond will be required for the site. Calculation of bond amounts will be conducted with the NT Security Calculation excel-based worksheet periodically throughout the mine life in accordance with regulatory requirements. Costs associated with reclamation bonding have been included in the technical economic model.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 273 20.5.1 Batman Pit Based on a preliminary regional groundwater flow model that included enlargement of the Batman pit and post-mining recovery of the groundwater system (outlined in Section 24.5– Regional Groundwater Model and Mine Dewatering), a terminal-sink pit lake may result during the post-closure phase, making active dewatering and treatment of pit water unnecessary following closure. All water inflow to the pit lake, including precipitation, storm-water runoff and groundwater, will leave the pit lake only via evaporation. No surface water or groundwater drainage from the pit lake is expected to occur. An access restriction berm (also termed “bund”) will be constructed around the perimeter of the Batman pit to impede human access and reduce the inflow of surface water to the pit. The safety berm will be offset 30 m from the pit perimeter per the requirements outlined in the guidelines “Safety Bund Walls around Abandoned Open Pit Mines” from the Department of Industry and Resources in Western Australia. 20.5.2 Waste Rock Dump The existing WRD will be slightly enlarged based on plans for the resumption of mining. The WRD will be constructed at an angle of repose slope of 1.5 vertical to 1.0 horizontal, with catch benches of 8.0 meters every 30 meters in height. Each lift will be constructed with 8 m wide benches at 30 m vertical intervals on the face of the WRD. As described in Section 16.0 – Mining Methods, the WRD will be constructed with an encapsulating non- PAG material outer shell on each lift. Concurrent installation of a low permeability geosynthetic liner (i.e., LLDPE or GCL) following attainment of final grades will serve to reduce infiltration of precipitation into the WRD core. This liner system will include a 0.3 m thick bedding layer of fine material to serve as liner bedding, followed by placement of the liner material, and capped with a 0.3-m thick protecting layer of fine material placed over the liner. The liner will span approximately 52 m on top of each lift, covering the 8 m bench, and running to just below the subsequent lift. The liner will be installed at five percent slopes toward the outside of the WRD, and will be constructed with a 0.5-m tall berm with 1:1 side slopes at the interior edge of the liner. A minimum 1-m thick layer of non-PAG waste rock will cover all surfaces of the WRD to aid in erosion control. Prior to WRD grading, a seepage collection system will be constructed along the down-gradient toe of the WRD and subsequently covered with waste rock from grading activities. ARD/ML collected by the WRD seepage collection system will initially be pumped to the New WTP for treatment prior to release until it is feasible to treat this and other ARD/ML on-site using a passive treatment system. 20.5.3 Tailings Disposal Facility The TSF embankment and impoundment surfaces will be reclaimed at closure by installing and revegetating a 1-m thick store and release cover. The 1-m thick store and release cover will consist of a 0.8-m thick layer of blended non-PAG waste rock (40%) and low-permeability material (60%), overlain by a 0.2-m thick layer of plant growth medium (PGM). Following placement, the cover surface will be roughened and revegetated with native species. The store and release cover will serve to effectively reduce percolation of precipitation into waste rock, PAG, and/or metalliferous materials. The majority of the impounded surface of the TSF at closure will be primarily composed of thixotropic tailings (thick like a solid but flows like a liquid when a sideways force is applied) which will maintain a

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 274 high degree of saturation for many years unless actively dewatered and consolidated, covered with material, or chemically treated to increase their strength. A crowned cover constructed using non-PAG and PAG waste rock and sorter reject material will result in a final tailing surface that drains and does not impound water. This crowned cover is assumed to adequately bridge the thixotropic tailings and allow for equipment to place the 1-m thick store and release cover. To the degree possible, store and release covers will be installed concurrently during construction when portions of facilities reach final grade. Storm water drainage, erosion, and sediment controls will be constructed to minimize erosion and scour of active reclamation areas. 20.5.4 Processing Plant and Pad Area A new process plant will be built for renewed mining. Once ore processing ceases, the process plant will be decommissioned, decontaminated, demolished and any reusable equipment and materials will be salvaged and resold. Material that cannot be treated in-situ will be excavated and disposed of in the WRD, TSF, or an off-site facility that is certified to accept and dispose of contaminated soil. Concrete foundations, building walls, and other inert demolition waste will be broken up and either: „ Placed in the WRD; „ Buried in-place; and/or „ Backfilled against cut banks and highwalls throughout the process plant and pad area, as well as other areas that will be reclaimed at Mt Todd. Surface and large shallow pipes will be removed and pipes at depth will be plugged with concrete or other suitable materials. The process plant area will be graded to blend into the surrounding topography and drain towards Batman Creek. The process plant area and pad will be covered with a 0.2-m thick layer of plant growth medium (PGM) and revegetated. Storm water drainage, erosion, and sediment controls will be constructed to minimize erosion. The WTP and equalization pond (EQP) will be left in place, up-graded if necessary, and used to treat acid rock drainage and metal-laden leachates (ARD/ML) during the closure and post-closure phases. These facilities will be closed when it is feasible to treat ARD/ML in passive treatment systems. 20.5.5 Heap Leach Pad and Pond The HLP and Pond will be left in place and reprocessed following processing of ore and low-grade ore. Following reprocessing of the heap material, the pad and pond footprint will be reclaimed by cutting and removing the liner for consolidation in TSF 2. It is anticipated that the integrity of the heap liner will have been compromised and removal of 0.5-m thick of impacted soils below the liner will be necessary. These materials would be removed and consolidated in TSF 2. The area will then be regraded to prevent ponding of water and will be covered with a 0.2-m thick layer of PGM and revegetated.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 275 20.5.6 Low Grade Ore Stockpile The existing LGOS1 will be eliminated during the expansion of the Batman Pit and it is assumed that no reclamation is required for the closure of this facility. The LGOS2 will be located near the pit and the process plant area. Closure of LGOS2 will include removal of residual ore from the stockpile areas, regrading, covering the material with a 0.2-m thick layer of PGM and revegetating the area. In addition, storm-water drainage, erosion, and sediment controls will be constructed to minimize erosion. It is assumed that RP2 will be closed during the closure phase and that the LGOS will no longer be a source of ARD/ML following closure. Any potential ARD generated during operations reports to the process water pond, and therefore the WTP. 20.5.7 Mine Roads Mine access roads will remain in place to provide post-closure access to the area. All haul roads will be closed by grading into surrounding topography, ripping subgrade materials, placing 0.2 m of PGM (when applicable), and revegetating the areas. 20.5.8 Water Storage Ponds Prior to construction of the active WTP, a process water pond (PWP) will be constructed for mixing of ARD/ML from various on-site sources prior to treatment and to temporarily store ARD/ML in case of system upset. All proposed and existing ponds at Mt Todd will be maintained for the collection of seepage, storm water and ARD/ML until long-term quality of water collected by the WRD seepage collection system meets applicable standards, flows to the collection system cease, or an alternative passive water treatment system is installed. The return water, polishing and overdrain ponds for the TSFs shall remain post-closure and be incorporated into the passive water treatment system. These and potentially other ponds may be used post-closure as backup water storage in case treatment upset occurs. To decommission and close ponds, residual standing water will be pumped to the PWP for processing by the WTP, and sediments and foundation materials will be tested to determine their chemical characteristics with acidic, PAG and metalliferous materials treated in-situ or buried in place. Following sediment testing and removal, pond liners will be cut and folded in place. Pond berms will be pushed into the pond void to cover the liners and until the area no longer impounds water. The top 0.6 m of graded material is assumed to have physical and chemical properties to support plant growth. Storm water drainage, erosion, and sediment controls will be constructed to minimize erosion and channel scour, and the areas will be revegetated. 20.5.9 Low Permeability Borrow Area A low permeability borrow area will be developed to provide low permeability material for use in project feature construction and for use in reclamation. As portions of the low permeability borrow area are taken out of service and are no longer used to generate material, they will be reclaimed by ripping and amending the remaining soils with organic matter, constructing channels to route drainage within the borrow area footprint and revegetating the area. Some portions of the low permeability borrow area may also be used as stock water ponds.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 276 20.5.10 Closure Cost Estimate Costs for reclaiming major facilities at the Project were estimated using closure material quantities based on ultimate designs and following the closure plans discussed above. Closure costs are accrued and contained in the financial model.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 277 21.0 CAPITAL AND OPERATING COSTS For the purposes of understanding how the mine will operate, Table 21-2 details the Project based on the principal operating time periods. Table 21-1: Operating Periods Principal Assumptions Unit Parameter Construction Period Years 2 Commissioning & Ramp-Up Years 0.5 Mine Life Years 13 Closure Period Years 4 Operating Days Days / Year 355 Costs are presented in Q3 2019 US dollars and are based on an US$0.70:AUD1.00 exchange rate, unless otherwise noted. Section 21.0 presents costs for incorporation into the Technical Economic Model (TEM). These costs are based on their source data and in some cases use different foreign exchange rates or unit rates for fuels, etc. The cash flow results presented in Section 22 are all tied to the same foreign exchange and unit costs rates. These costs are summarized using the listed foreign exchange rate provided in Section 22.0 – Economic Analysis. 21.1 Capital Cost LoM capital cost requirements are estimated at US$1,222 million as summarized in Table 21-2. Initial capital of US$826 million is estimated to be required to commence operations. At the end of operations, the Project will receive a US$140 million credit for remaining asset sales and salvage (reference Table 22-13).

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 278 Table 21-2: Estimated Capital Cost Summary (US$000s) Area Description Cont. (%) Initial Capital (US$000s) Sustaining Capital (US$000s) Total Capital (US$000s) Estimate Contingency Total Estimate Contingency Total Estimate Contingency Total 2000 Mining 7.3% $121,239 $5,720 $126,958 $406,347 $32,677 $439,024 $527,586 $38,396 $565,982 3000 Process Plant 13.9% $366,693 $51,073 $417,766 $17,027 $2,222 $19,249 $383,720 $53,295 $437,016 4000 Project Services 10.0% $109,204 $12,681 $121,885 $72,448 $5,455 $77,903 $181,651 $18,136 $199,787 5000 Project Infrastructure 13.2% $26,160 $3,463 $29,623 $0 $0 $0 $26,160 $3,463 $29,623 6000 Permanent Accommodation 10.0% $60 $6 $66 $0 $0 $0 $60 $6 $66 7000 Site Establishment & Early Works 11.4% $17,537 $1,995 $19,532 $0 $0 $0 $17,537 $1,995 $19,532 8000 Management, Engineering, EPCM Svcs 11.8% $82,058 $9,721 $91,779 $0 $0 $0 $82,058 $9,721 $91,779 9000 Pre-Production Costs 12.3% $16,121 $1,982 $18,102 $0 $0 $0 $16,121 $1,982 $18,102 10000 Asset Sale 0.0% $0 $0 $0 ($139,631) $0 ($139,631) ($139,631) $0 ($139,631) Capital Cost 11.6% $739,072 $86,641 $825,712 $356,191 $40,354 $396,545 $1,095,263 $126,994 $1,222,257

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 279 21.1.1 Mining (MDA) Table 21-3 shows the estimated mine capital requirements by year. The initial mine capital is estimated to be US$115 million, with a LoM capital of US$414 million. This includes capitalized operating costs of US$68 million for construction, US$20 million for pre-stripping, and US$31 million for reclamation. Note that the treatment of the capitalized mining in the final cash-flow model differed slightly, but the difference is insignificant ($4,000 less). Table 21-3: Estimated Mine Annual Capital Costs (US$000s) Pre-Prod Yr 1 Yr 2 Yr 3 Yr 4 Yr 5 Yr 6 Yr 7 Yr 8 Yr 9 Yr 10 Yr 11 Yr 12 Yr 13 Yr 14 Total PRIMARY MINING EQUIPMENT Atlas Copco PV235 $ 14,811 $ 2,468 $ 9,874 $ 12,342 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 39,495 165mm Rotory Blast Hole Drill $ 1,242 $ 1,242 $ 0 $ 1,242 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 3,725 28m3 Hyd. Shovel (PC 5000) $ 17,308 $ 8,654 $ 0 $ 8,654 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 34,616 19m3 Front End Loader (994) $ 0 $ 9,146 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 9,146 250t Haul Truck $ 43,382 $ 4,338 $ 56,397 $ 34,706 $ 8,676 $ 8,676 $ 4,338 $ 4,338 $ 13,015 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 177,868 Total Primary Equipment $ 76,743 $ 25,848 $ 66,271 $ 56,994 $ 8,676 $ 8,676 $ 4,338 $ 4,338 $ 13,015 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 264,850 SUPPORT EQUIPMENT 630 Kw Dozer (D11) $ 1,912 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 1,912 300 Kw Dozer (D9) $ 967 $ 0 $ 967 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 967 $ 967 $ 0 $ 0 $ 0 $ 0 $ 3,867 7.3 m Motor Grader (24M) $ 2,561 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 2,561 4.9 m Motor Grader (16H) $ 997 $ 0 $ 997 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 997 $ 997 $ 0 $ 0 $ 0 $ 0 $ 3,988 Water Truck - 70,000 Liter $ 4,217 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 4,217 RTD Dozer (834H) $ 1,150 $ 0 $ 1,150 $ 0 $ 0 $ 0 $ 0 $ 0 $ 1,150 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 3,451 Rock Breaker - Impact Hammer (691 Kg m) $ 43 $ 0 $ 0 $ 0 $ 0 $ 0 $ 43 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 86 Backhoe/Loader (1.5 cu m-446D) $ 281 $ 0 $ 0 $ 0 $ 0 $ 0 $ 281 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 561 Pit Pumps (5299 lpm) $ 55 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 55 36 ton Crane $ 365 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 365 2 cm excavator (Cat 392) $ 358 $ 0 $ 0 $ 0 $ 0 $ 0 $ 358 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 716 Low Boy $ 994 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 994 Flatbed $ 56 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 56 Manlift $ - $ 0 $ 0 $ 0 $ 21 $ 21 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 42 Total Support Equipment $ 13,954 $ 1,980 $ 0 $ 559 $ 21 $ 21 $ 681 $ 2,736 $ 1,150 $ 1,964 $ 1,964 $ 0 $ 0 $ 0 $ 0 $ 22,868 BLASTING Skid Loader $ 57 $ 0 $ 0 $ 0 $ 57 $ 0 $ 0 $ 57 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 171 Total Blasting $ 57 $ 0 $ 0 $ 0 $ 57 $ 0 $ 0 $ 57 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 171 MINE MAINTENANCE Lube/Fuel Truck $ 602 $ 0 $ 0 $ 0 $ 0 $ 0 $ 301 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 903 Mechanics Truck $ 187 $ 0 $ 0 $ 187 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 374 Tire Truck $ 137 $ 0 $ 0 $ 137 $ 0 $ 0 $ 137 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 411 Total Mine Maintenance $ 926 $ 0 $ 0 $ 247 $ 0 $ 0 $ 438 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 1,688

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 280 Pre-Prod Yr 1 Yr 2 Yr 3 Yr 4 Yr 5 Yr 6 Yr 7 Yr 8 Yr 9 Yr 10 Yr 11 Yr 12 Yr 13 Yr 14 Total OTHER MINE CAPITAL Light Plant $ 66 $ 33 $ 33 $ 0 $ 0 $ 66 $ 33 $ 16 $ 16 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 263 Mobile Radios $ 55 $ 7 $ 21 $ 38 $ 4 $ 3 $ 21 $ 7 $ 5 $ 2 $ 2 $ 0 $ 0 $ 0 $ 0 $ 165 Shop Equipment $ 491 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 491 Engineering & Office Equipment $ 200 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 200 Water Storage (Dust Suppression) $ 98 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 98 Base Radio & GPS Stations $ 105 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 105 Unspecified Miscellaneous Equipment $ 150 $ 0 $ 0 $ 2,000 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 2,150 Access Roads - Haul Roads - Site Prep $ 175 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 175 Light Vehicles $ 726 $ 50 $ 50 $ 813 $ 50 $ 50 $ 603 $ 210 $ 50 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 2603 Total Other Mine Capital $ 2,066 $ 90 $ 104 $ 2,851 $ 54 $ 119 $ 657 $ 233 $ 72 $ 2 $ 2 $ 0 $ 0 $ 0 $ 0 $ 6,250 CAPITALIZED MINE OPERATING COSTS Pre-Stripping Mining Cost $ 19,489 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 19,489 Tailings Construction Costs $ 1,631 $ 2,060 $ 6,612 $ 7,062 $4,293 $ 3,187 $ 4,703 $ 4,250 $ 10,776 $ 0 $ 11,357 $ 11,258 $ 1,240 $ 0 $ 0 $ 68,430 Reclamation (Occurs in Years 13 and 14) $ 7,729 $ 22,843 $ 30,575 Total Capitalized Mining Costs $ 21,137 $ 2,060 $ 6,608 $ 7,063 $4,294 $ 3,188 $ 4,702 $ 4,249 $ 10,779 $ 0 $ 11,359 $ 11,257 $ 1,241 $ 7,730 $ 22,823 $ 118,494 CAPITAL SUMMARY Primary Mining Equipment $ 76,743 $ 25,848 $ 66,271 $ 56,944 $ 8,676 $ 8,676 $ 4,338 $ 4,338 $ 13,015 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 264,850 Support Equipment $ 13,954 $ 0 $ 3,114 $ 0 $ 21 $ 21 $ 681 $ 0 $ 1,150 $ 1,964 $ 1,964 $ 0 $ 0 $ 0 $ 0 $ 22,868 Blasting $ 57 $ 0 $ 0 $ 0 $ 57 $ 0 $ 0 $ 57 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 171 Mine Maintenance $ 926 $ 0 $ 0 $ 324 $ 0 $ 0 $ 438 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 0 $ 1,688 Other Mine Capital $ 2,066 $ 90 $ 104 $ 2,851 $ 54 $ 119 $ 657 $ 233 $ 72 $ 2 $ 2 $ 0 $ 0 $ 0 $ 0 $ 6,250 Capitalized Mine Operating Costs $ 21,137 $ 2,060 $ 6,008 $ 7,063 $4,294 $ 3,188 $ 4,702 $ 4,249 $ 10,779 $ 0 $ 11,359 $ 11,257 $ 1,241 $ 7,730 $ 22,823 $ 118,494 Total - All Mining Capital $ 114,882 $ 27,999 $ 76,097 $ 67,181 $ 13,103 $ 12,005 $ 10,817 $ 8,878 $ 25,016 $ 1,966 $ 13,324 $ 11,257 $ 1,241 $ 7,730 $ 22,823 $ 414,322

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 281 21.1.1.1 Drilling and Blasting Primary drilling equipment capital is based on equipment quotations for a total of 16 Atlas Copco Pit Viper 235 blast-hole drills required through the life of mine. Eight of the drills will be purchased at the start of mining in Year -1, an additional three drills purchased in Year 1, and then four additional drills will be purchased in Year 3 at a cost of US$ 2,468,400 each (including shipping and assembly). The cost of the drills was provided by EMG LLC. In addition to the production drills, smaller 45K pull-down drills will be used for pre-split drilling. These will use 165mm bits and will cost approximately US$ 1,241,800 each. One drill is purchased in Year -1, one more in year 1, and a replacement drill has been planned for Year 6. Quotes for explosives trucks, powder magazines, and bulk ANFO storage has been obtained by TTP. These capital costs are included in the infrastructure costs. Additional, capital expense for a skid loader is provided to be used by the blasting crew for stemming holes. The skid loader would be purchased at an estimated cost of US$ 57,000 during Year -1 and then two additional units would be purchased in Year 4 and Year 7. 21.1.1.2 Loading Capital costs for loading equipment have been quoted by EMG LLC and include four Komatsu PC5000 hydraulic shovels and two Caterpillar 994 Loaders. Two of the hydraulic shovels would be purchased during Year -1, with a third being purchased during Year 1. The fourth shovel is purchased in Year 3. The estimated cost for each shovel is US$ 8,653,900, which includes freight and assembly. The cost of the 18-cubic meter loaders is based on a quote for a Caterpillar 994 loader, with the first one being purchased at the start of production in Year 1, and the second purchased in Year 2, at a cost of US$ 4,573,100 each. 21.1.1.3 Haulage The 226-tonne haulage truck costs are based on CAT 793F trucks and were quoted by EMG LLC. Nine trucks are purchased during Year -1, with another 8 trucks purchased in Year 1. Trucks are purchased as they are required through the mine life. The trucks are staged in to allow ramp up of production through each year as they are needed to meet production requirements. The total number of trucks required by year is shown as follows: Number of Trucks Year Trucks Added in Use -1 8 8 1 3 11 2 11 22 3 5 27 4 6 33 5 2 35 6 2 37 7 1 38 8 3 41 9 0 41 10 0 41 11 0 22 12 0 6 13 0 6 14 0 6

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 282 Throughout the mine life, a total of 41 trucks are purchased. The number of operating trucks is reduced toward the end of the mine life as haulage requirements are decreased. The cost of each truck is estimated at US$ 4,338,200, including freight and assembly. 21.1.1.4 Mine Support Capital estimates for mine support equipment include freight and erection. The initial support equipment to be purchased in Year -1 is as follows: „ One Caterpillar D11 track dozer (US$ 1,911,600 each quoted by EMG LLC); „ Four Caterpillar D9 track dozers (US$ 966,700 each quoted by EMG LLC); „ One Caterpillar 24M motor grader (US$ 2,560,600 quoted by EMG LLC); „ Four Caterpillar 16H motor graders (US$ 996,900 quoted by EMG LLC); „ Two Caterpillar 777 trucks with 70K liter water tanks (US$ 2,108,700 quoted by EMG LLC); „ Three Caterpillar 834H rubber tire dozers (US$ 1,150,300 quoted by EMG LLC); „ Two Caterpillar 392DL excavators (US$ 357,900 quoted by EMG LLC); „ One low-boy trailer complete with a used 60t haul truck to tow it (US$ 993,600); „ One flatbed truck (US$ 55,700); „ Two pit pumps (US$ 27,500 each); „ Two rock breakers to be attached to the 392DL excavator as needed (US$ 42,800); and „ 16 light plants (US$ 16,400). Replacements are purchased for most units in Year 6. 21.1.1.5 Maintenance Capital for mine maintenance equipment includes three fuel/lube trucks (US$ 301,000 each), two mechanic’s truck (US$ 187,000 each), and three tire trucks (US$ 137,000 each). Note that requirements for mechanic’s trucks are reduced through year 3 due to the assumption of MARC for maintenance. This single mechanic’s truck is intended for support of a small number of owner-operated equipment. At year 3, an additional mechanics truck is put into service. An additional US$ 491,000 has been included for shop equipment / tooling. Shop facilities are included in facility capital. 21.1.1.6 Mine Facilities Mine facility capital is included in facility capital. 21.1.1.7 Light Vehicles Initial capital for light vehicles is estimated to be US$ 540,000 while sustaining light vehicle capital is US$ 1,047,200. Initial and sustaining light vehicle capital is shown in Table 21-4.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 283 Table 21-4: Estimated Mine Light Vehicle Capital (US$ ) Type Initial Capital (US$ ) Sustaining Capital (US$ ) Quantity Unit Cost Ext. Cost Quantity Unit Cost Ext. Cost MINE DEPARTMENT Mine Superintendent 3/4 ton 4wd Pickup 1 $ 44,100 $44,100 2 $ 44,100 $88,200 Shift Foreman 4wd Pickup 2 $ 36,400 $72,800 9 $ 36,400 $327,600 Trainer 4wd Pickup 1 $ 32,200 $32,200 2 $ 32,200 $64,400 Blasting 4wd Pickup 1 $ 36,400 $36,400 2 $ 36,400 $72,800 Blasting 1 ton 4wd Pickup 1 $ 36,400 $36,400 2 $ 36,400 $72,800 Crew Vans 3/4 ton Passenger Van 2 $ 50,400 $100,800 11 $ 50,400 $554,400 ENGINEERING Chief Engineer 4wd Pickup 1 $ 36,400 $36,400 2 $ 36,400 $72,800 Short Range Planning 4wd Pickup 1 $ 32,200 $32,200 2 $ 32,200 $64,400 Survey 4wd Pickup 1 $ 36,400 $36,400 2 $ 36,400 $72,800 GEOLOGY Chief Geologist 4wd Pickup 1 $ 36,400 $36,400 2 $ 36,400 $72,800 Ore Control 4wd Pickup 1 $ 32,200 $32,200 2 $ 32,200 $64,400 Samplers 4wd Pickup 1 $ 32,200 $32,200 2 $ 32,200 $64,400 MINE MAINTENANCE Maintenance Superintendent 4wd Pickup 2 $ 36,400 $72,800 4 $ 36,400 $145,600 Mechanics / Labor 4wd Pickup 2 $ 32,200 $64,400 4 $ 32,200 $128,800 Total 18 $665,700 48 $1,866,200

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 284 21.1.1.8 Other Mine Capital Other miscellaneous capital includes mobile radios for mobile equipment (US$ 1,000 per unit), engineering and office equipment ($ 200,000 US), water storage for dust suppression (US$ 97,900), GPS stations and surveying equipment (US$ 105,000), and other unspecified miscellaneous equipment (US$ 150,000). At the end of year three, Mt Todd personnel will take over the maintenance of equipment. Accordingly, US$ 2,000,000 as unspecified equipment has been added in year three for additional maintenance equipment. 21.1.2 CIP Process and Infrastructure (TTP) Please note that this Section describes costs in Australian Dollars (AUD). Capital cost estimates (CCEs) are based on an Enhanced Factored Cost Estimate (EFCE) methodology, which features higher confidence levels around Contingency Provision and Management Reserve. The capital estimates are supported by the design work carried out throughout the study including process documentation, schematics, general arrangement drawings, 3D models and calculations (reference Table 21-5). Note all currencies are in Australian Dollars. Table 21-5: Estimated Capital Cost Summary (AUD000s) Capital Cost Initial Capital (AUD000s) Facility 1000 – Geology 0.000 Facility 2000 – Mine Infrastructure 15,689 Facility 3000 – Process Plant 587,690 Facility 4000 – Project Services 16,654 Facility 5000 – Project Infrastructure 39,048 Facility 6000 – Permanent Accommodation 0,074 Facility 7000 – Site Establishment & Early Works 27,903 Facility 8000 – Management, Engineering, EPCM Services 94,353 Facility 9000 – Preproduction Costs 19,312 Subtotal 617,316 Direct 574,468 Indirect 125,731 Subtotal 700,199 Contingency Provision (14.6%) 100,544 TOTAL 800,744 The total capital cost, base cost plus contingency provision, represents the expected cost for the project, with approximately a 55% confidence level of completion within cost. This estimate has an accuracy range of approximately -0 to 15% based on the expected cost. At the upper limit of the accuracy range, there is an 85% confidence level of completion within cost.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 285 Typically, the EPCM Project Manager would initially receive Owner’s approval for expenditure up to the expected cost (i.e., this is the initial project budget). However, funding arrangements would also need to be in place for expenditure up to the 85% confidence level. This additional funding is commonly referred to as Management Reserve. The selection of Management Reserve quantity will rest with Vista, and will be determined by Vista’s attitude to risk. 21.1.2.1 Exclusions The TTP scope of work is a significant part of the overall Project scope, although other parties have compiled capital costs for other areas on behalf of Vista. The potential impacts of possible price or labor rate fluctuations or currency exchange rate fluctuations are the role of a qualified actuary and should be covered by Vista in its standard business practices. 21.1.2.2 Capital Cost Estimating Methodology A PFS design has been developed for a 50,000 tpd plant as the basis for an EFCE. The EFCE approach uses a combination of bottom-up calculations and factoring methods for each area in the estimate. The methods used to estimate capital in the CCE are summarized in the following sections. The EFCE for the process plant features the methodology shown in the table below. Table 21-6: CCE Methodology for Facility 3000 – Process Plant Bulk Commodity Methodology Mechanical Equipment A detailed mechanical equipment list, with supply and installation pricing based on budget quotations and internal body of knowledge Concrete MTOs based on 3D model and unit rates. Structural Steel MTOs based on 3D model and unit rates. Platework MTOs from previous projects a unit rates Tankage MTOs based on preliminary design calculations and unit rates Piping Percentage factor of the supplied mechanical equipment supply price, assessed on an area by area basis. Electrical Percentage factor based on total mechanical equipment supply price Instrumentation and Control Costs factored. Subsequently estimate factors, by area, were back calculated for each bulk commodity as a percentage of the mechanical equipment supply cost estimate. In turn, the resultant estimate factors were critiqued against published data and industry experience.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 286 21.1.2.3 Other Area Capital Cost Estimates The EFCE for all areas outside of the process plant features the methodology shown in Table 21-7. Table 21-7: Methodology for Other Areas of the Capital Cost Estimate Area / Sub Area Methodology FACILITY 2000 – MINE Area 2300 – Mine Support Facilities Drawings developed for the buildings and priced largely on a building per square meter basis Area 2400 – Mine Support Services Drawings developed for the buildings and priced largely on a building per square meter basis FACILITY 4000 – PROJECT SERVICES Area 4100 – Water Supply Sub-area 4110 – Water Supply WTP estimated by Tetra Tech Golden Office Sub-Area 4120 – Raw Water Distribution was estimated by mechanical equipment costs and factoring of bulk commodities Area 4200 – Power Supply Based on length of power distribution cables and trenching, and overhead power lines using rates developed from previous projects. Power – Generation (7.3.1) is by Power Engineers Area 4300 – Communications Based on MTOs for the fiber optic cables, phones and telemetry using budget pricing and rates developed from previous projects. Area 4200 – Power Supply Based on length of power distribution and overhead power lines and rates developed from previous projects Area 4300 – Communications Based on MTOs and provisional sums for the fiber optics, phones and telemetry Area 4400 – Tailings Dam Estimated by Tetra Tech Golden Office Area 4500 – Waste Disposal Based on provisional sums for sewerage services from previous project designs Area 4600 – Plant Mobile Equipment Vendor pricing of the proposed fleet for plant operation FACILITY 5000 – PROJECT INFRASTRUCTURE Area 5100 – Site Preparation Based on MTOs from preliminary drawings and rates developed from first principles Area 5200 – Support Buildings Drawings developed for the buildings and priced largely on a building per square meter basis Area 5300 – Access Roads, Parking and Laydown Provisional sums based on miscellaneous road and culvert repairs Area 5400 – Heavy Lift Cranage Based on the proposed fleet for plant construction and rates from previous project experience Area 5600 – Bulk Transport Based on the mechanical equipment cost for the weigh bridge and MTO for concrete Area 5800 – Communications Based on budget pricing and quantities provided by Vista

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 287 Area / Sub Area Methodology FACILITY 6000 – PERMANENT ACCOMMODATION Area 6100 – Personnel Transport Based on unit rates for bus shelters with an allowance for the small amount of concrete required FACILITY 7000 – SITE ESTABLISHMENT AND EARLY WORKS Area 7300 – Construction Camp Based on MTOs for the access roads and site works and vendor quotes for the camp and operation FACILITY 8000 – MANAGEMENT, ENGINEERING, EPCM SERVICES Area 8100 – EPCM Services Factored up from 33,000 tpd Case based on the Total Direct Costs Area 8200 – External Consultants/Testing Provisional Sums based on previous project experience Area 8300 – Commissioning Process Plant commissioning costs based on 3% of the total mechanical equipment costs. Provisional Sums allowed for Mine, Project Services and Infrastructure commissioning. Area 8400 – Owners Engineering/Management Based on 2% of the project direct costs. Area 8800 – License, Fees and Legal Costs Based on 0.5% of the project direct costs. Area 8900 – Project Insurances Based on 0.5% of the project direct costs. FACILITY 9000 – PRE-PRODUCTION COSTS Area 9100 – Preproduction Labor Based on 0.25% of the project direct costs. Area 9200 – Commissioning Expenses Based on 0.5% of the project direct costs. Area 9300 – Capital Spares Based on 5% of the mine and process plant mechanical equipment costs. Area 9400 – Stores and Inventories Based on 1% of the mine and process plant mechanical equipment costs Area 9800 – Contingency Provision Priced based on a weighted average of the contingency of each facility Area 9900 – Management Reserve Provision A weighted average Management Reserve of 20% was allowed for, the selection of Management Reserve quantity will rest with Vista, and will be determined by Vista’s attitude to risk. 21.1.2.4 Construction Labor Rates A detailed calculation of composite, direct man-hour site rates has been carried out using TTP standard templates. The calculation is based upon current ordinary time wages for various classes of labor including direct supervision, to which the following factor may apply; site allowance, tool allowance, leave provisions, taxes and insurances, overtime, etc. This develops a gang rate that is combined with costs of incumbent support equipment (such as light vehicles, light mobile cranes, small tools, consumables, first-aid facilities and accommodation) and management support to arrive at an all-purpose site gang rate.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 288 The construction labor rates developed for the CCE include the following construction contractors: „ Concrete; „ Structural, Mechanical and Piping (SMP); and „ Electrical and Instrumentation (E&I). BASE LABOR RATES The base labor rate includes the direct labor allocated for the installation of equipment and bulk commodities. Base pay rates were derived from award rates for similarly sized projects currently underway in the North West of Western Australia and in the Northern Territory. These are considered to be the benchmark for the area, including Mt Todd. Allowances were made for overtime loadings above a 36-hour week including time and a half for the initial 12 hours overtime, followed by double time for the final 17 hours overtime, to provide for a 65-hour working week. The rates were averaged over a standard mix of trades, to produce a composite rate per man per hour. The base labor rates were developed to include items listed below: „ All direct payments including the site allowances and special project allowances for straight time and overtime worked for personnel; „ Overtime at penalty rates; „ Provision for holiday leave and loadings thereon; „ Provision for sick leave; „ Provision for cost of travel time to site and return travel on job completion; „ Provision for additional manpower turnover, bereavement leave and miscellaneous paid non- work days; „ Payroll tax; „ Workers compensation insurance; „ Superannuation considerations; and „ Industry redundancy payments. A rest and recreation (R&R) loading was also added to the composite rate, together with a 15% contractors allowance for overheads and margin to produce the base labor rate for each contractor type. CONTRACTOR INDIRECT RATES The contractor indirect rate is a combination of costs associated with indirect contractor personnel, contractor vehicles, contractor overheads and construction plant equipment. An estimate of construction contract duration and installation hours was based on the EPCM schedule and bulk quantity development. The contractor indirect rates were developed to include the items listed below: „ Project Management personnel; „ Construction Supervision personnel; „ Site Quality Assurance and Control personnel; „ Site Health, Safety, Environmental personnel; „ Other indirect labor (stores officer, surveyor, etc.); „ Contractor vehicles for the Project Management team; „ Office accommodation;

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 289 „ Workshop and stores facilities; „ Staff travel including airfares ; „ Office overheads; and „ Vehicle consumables. Provisions for the accommodation and messing are also not included in the indirect contractor rates. This is allowed for in the construction camp cost estimate to supply and operate the camp. Although they are considered indirect costs, construction plant equipment rates are estimated separately to include the following: „ Construction plant equipment mobilization / demobilization; „ Construction plant management support; and „ Construction plant and equipment. The provision for task specific heavy lift cranes >50 tonnes were not included in the indirect contractor rates build-up; instead it was allowed for in a separable line item in the chart of accounts (CoA). CONSTRUCTION GANG RATES The overall site construction gang rates were developed by summing the base labor rate, contractor indirect rates and construction plant rates to provide an overall site construction gang rate for Concrete, SMP and E&I contractors as shown in Table 21-8 below. Table 21-8: Estimated Construction Gang Rate Development (AUD) Contractor Base Labor Rate (AUD/hr) Contractor Indirect Rate (AUD/hr) Construction Plant Rate (AUD/hr) Construction Gang Rate (AUD/hr) Concrete $ 89.69 $ 23.98 $ 24.36 $ 138.03 SMP $ 98.75 $ 45.31 $ 20.84 $ 164.90 E&I $ 104.03 $ 56.27 $ 24.07 $ 184.36 21.1.2.5 Mechanical Equipment The supply costs comprise the direct mechanical equipment cost plus the cost for freight to site. Installation costs are estimated based on an evaluation of installation hours multiplied by the SMP contractor gang rate. These estimating methods are discussed in the following sections. EQUIPMENT COSTS The basis for estimating the mechanical equipment supply costs was largely based on budgetary pricing from vendors. The vendors were provided with preliminary specifications and/or data sheets for major equipment items. The budget quotations received from vendors are expected to have an accuracy equal to ±10%. All other minor equipment items were priced from a TTP’s database of costs from recent similar sized projects. The basis of the supply cost estimate for each mechanical equipment line item is documented in the process plant CCE.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 290 FREIGHT COSTS Several methods were used to determine and validate the allowance for delivery costs of mechanical equipment to site. These methods included: „ Quotes provided by the manufacturer; „ Estimates based on the weight and volume of the load; „ Estimates based on published and in-house guides for similar installations; and „ Estimates based on a validated percentage of the mechanical equipment cost (determined to be 9% of the supply price). INSTALLATION HOURS Several methods were used to determine and validate the installation hour allowance for mechanical equipment. These methods included: „ Quotes provided by the manufacturer; „ Estimates based on the weight of the equipment; and „ Estimates based on published and in-house guides for similar installations. The installation hour estimates for large process equipment (>3000 man hours/ equipment) including the crushers, HPGRs, ball mills, VXP mills and thickeners were reviewed in detail against historical records and published guidelines. 21.1.2.6 Quantity Development and Unit Rates The basis for the development of supply and installation costs of bulk commodities is discussed in the following section. Bulk commodities include civil, concrete, structural steel, etc. which will be used in the construction of the process plant. These costs were largely derived based on an estimate of material take-off (MTO) quantities which were multiplied by a unit rate for each type of material. The unit rates were calculated using TTP standard methods including obtaining current market rates from contractors, historical data and reference books (Rawlinsons) and comprise of allowances for supply of the raw material, fabrication, freight and erection. CIVIL Preliminary bulk earthwork quantities were estimated using civil 3D modelling software 12D Model. The 12D Model accurately calculates earthworks volumes utilizing the existing topography and proposed design levels. Structural excavation and backfill required for concrete structures are included in the concrete quantities. Trenching requirements for underground utilities distribution were determined from service plans. Stormwater drainage quantities were determined from the civil site plan with vee-drains alongside plant roads directing surface run-off beneath roads via corrugated steel culverts. All quantities were categorized by standard type of work classification. Unit rates for this work classification were developed from the in-house rates database. This rates database is constantly maintained so as to be current and has proven to be sufficiently accurate over several recent projects. The availability of water and local earthworks materials was taken into account in to the development of unit rates.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 291 CONCRETE Concrete quantities for foundations and ground slabs for all equipment and structures in the process plant were calculated by 3D models. Concrete quantities were categorized by standard classes of concrete including spread/pad footings, strip footings, raft footings, ring beams, ground slabs, walls, sumps and pits, etc. Unit pricing was obtained from industry sources by standard classification, each having an assessment of formwork, props, bracing reinforcing, embedment’s, joints in slabs plus a miscellaneous allowance for curing, formwork hardware and other sundries. Concrete supply was costed at a rate deemed to include plant control testing, some admixtures and out of hours pouring. A wastage factor was included in the rates. A Contractor’s mark-up was also applied to all materials. Direct labor unit man-hours were sought from industry sources and checked against historical data and various published references. STRUCTURAL STEEL Steel quantities were categorized by standard classes of steel including light, medium, heavy and very heavy. There are also provisions made for grating, handrailing and stair treads. Unit rates for the supply and installation of structural steel were calculated using TTP Standard templates. Supply of steel was based on rates quoted from Thai fabricators from a similar project. The supply rate includes provisions for steel supply, shop drawings, shop fabrication, painting and freight to site. Estimates for the installation costs of structural steel are based on estimates of erection hours and the SMP gang rate. PLATEWORK Quantities of steel required for custom designed platework was calculated using the 3D models. The cost items for platework includes plate thicknesses of <10mm, 12-20mm and floor plate of 6mm and also allowances for Bisalloy or rubber lining where applicable. Unit rates for platework were provided by Thai fabricators as is described for structural steel. TANKAGE Quantities of steel required for custom designed tankage were quantified by structural engineers using TTP standard spread sheets to determine the required tank shell and base thickness in accordance with the provisions of API 650. This includes allowances for the mass of steel for shell plates, top rings, and base plates. Unit rates for supply and installation of tankage were based on Thai fabricated steel using the same methodology as is described for structural steel. There are two classes of tankage allowed for in the CCE including shop fabricated and site erected tanks (assumed to be greater than 7m in diameter). PIPING The estimate for the supply and installation of process piping was factored based on a percentage of the supplied mechanical equipment price, assessed on an area by area basis. These percentages were based on in-house and industry typical piping allowances for similar gold plants. These factors were validated with values reported in published guidelines.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 292 ELECTRICAL The estimate for the supply and installation of electrical components for the process plant was factored based on a percentage of the total Mechanical Equipment supply and installation cost. These percentages were based on in-house and industry typical electrical allowances for similar gold plants. INSTRUMENTAL AND CONTROL The estimate of Instrumentation and Control costs for the 50,000 tpd gold plant was up-scaled by 30% from an estimate for the supply and installation of the Instrumentation and Process Control System from preliminary P&IDs and equipment lists for a highly automated 33,000 tpd gold plant with all field instruments marshalled to remote Input / Output (I/O) cabinets. 21.1.2.7 Indirect Costs CONSTRUCTION CAMP An estimate of the construction facilities was developed from previous project experience for the various scopes of work. This includes a breakdown of costs for contractor preliminaries, transportable building (supply and install) and establishing the infrastructure, power supply, communications and water supply. It also includes allowances for removal of the infrastructure following completion. Provisions were made for the operation of the camp based on a man-day rate. The man-day rate applied is based on budget enquiries for appropriate contractors. EPCM SERVICES Engineering, drafting and documentation functions are task and deliverable related. Hence, their estimates were based on task and deliverable identification with time estimates based in industry experience. Procurement activities were estimated from hours related to purchasing, expediting, inspection and transport functions derived by time involvements, and then checked against industry experience. Management, administrative and project engineering functions are mostly time-related and were assessed by title, rate and man-months of key personnel and other staff proposed. To the extent possible, site office items were detailed and estimated on an item-by-item basis. Management, supervisory and administrative staffing were estimated on an hours basis. EXTERNAL CONSULTANTS AND TESTING Cost allowances for Environmental, Human Resources and Industrial Relations, and Health and Safety consultants are based on industry experience of required manning and market contract values. OTHER INDIRECT COSTS The following costs were calculated based on industry validated percentages of the total direct costs of the Project: „ Owners engineering / management; „ License, fees and legal costs; „ Project insurances; and „ Pre-production labor.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 293 The following costs were calculated based on industry validated percentages of the mechanical equipment supply cost for the Project: „ Commissioning Expenses; „ Capital Spares; and „ Stores and Inventories. 21.1.2.8 Contingency Provision The contingency provision is an allowance added to an estimate to provide for costs which cannot be estimated due to inadequate information, but which are known to be implicit in the scope. The contingency provision represents costs which are expected to be incurred to complete the project and must be regarded as part of the total funds placed under the direct control of the project manager. The contingency provision includes an allowance for: „ Unidentified items not included in the quantity calculations or equipment lists, due to lack of knowledge, but implicit in the scope. „ Small changes, arising from detailed design, which normally occur during the course of the project, as knowledge becomes firmer. „ Design Omissions. Changes in concept, scope or production rates which depart from those on which the estimate has been based require a new estimate. These changes are not allowed for in the contingency. 21.1.3 Power Plant (POWER Engineers) Please note that this Section describes costs in Australian Dollars (AUD). Estimated capital costs compiled for this study cover direct and indirect costs of power station construction including equipment quoted from suppliers, material quantities estimated from the preliminary design, and installation labor and supervision with local material and labor costs applied to those estimates. Power plant estimated capital costs are shown in Table 21-9 in Australian dollars. Table 21-9: Estimated Power Station Installed Capital Cost Summary (AUD) 69.6 MW (Seven Reciprocating Engines) (AUD) Reciprocating Engines $32,705,556 BOP Equipment $10,448,551 Mechanical, Civil, & Electrical Direct Costs $48,650,267 Engineering Fees $6,944,444 Contractor’s Fees $6,002,083 Taxes, and Other Indirect Costs $10,938,749 Total Installed Costs AUD $115,689,650 Capital Cost per Net Installed Capacity AUD/kW $1,624

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 294 21.1.4 Mine Dewatering (Tetra Tech) Mine dewatering capital costs are based on direct vendor quotes or Tetra Tech in-house estimates and include 5% indirect costs. Table 21-10: Estimated Mine Dewatering Capital Cost Summary (US$000s) WBS No. Description Initial Capital (US$000s) Sustaining Capital (US$000s) Total Capital (US$000s) 2501 PPD Dewatering $532 $0 532 2502 Self-Priming Pump on Pontoon $0 $0 0 2503 Pump $50 $299 349 2504 Piping in Pit $74 $114 188 2505 Piping from Pit to PWP $287 $0 287 2506 Electrical $27 $41 68 2507 Indirects $16 $19 35 2500 Mine Dewatering/Drainage $987 $473 1,459 21.1.5 Reclamation and Closure (Tetra Tech) Costs for reclaiming major facilities at the Project were estimated using closure material quantities based on ultimate designs and following the closure plans discussed above. Capital costs for reclamation are estimated at US$138 million for LoM. Table 21-11: Estimated Reclamation Capital Cost Summary (US$000s) WBS No. Description Initial Capital (US$000s) Sustaining Capital (US$000s) Total Capital (US$000s) 2901 Heap Leach Pad $0 $1,009 1,009 2902 Low Grade Ore Stockpile $103 $645 747 2903 TSF 1 $0 $28,875 28,875 2904 TSF 2 $0 $32,991 32,991 2905 WRD (GCL Cover) $0 $36,163 36,163 2906 Process Plant Area $0 $8,555 8,555 2907 Soil Stockpiles $0 $226 226 2908 Mine Roads $0 $397 397 2909 Batman Pit $0 $1,131 1,131 2910 Passive Treatment Systems $0 $3,722 3,722 2911 Indirect Costs $21 $24,393 24,415 2900 Mine Closure $124 $138,108 138,232

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 295 21.1.6 Water Treatment Plant (Tetra Tech) Water treatment plant capital costs are based on direct vendor quotes or Tetra Tech in-house estimates, initial capital costs are estimated at US$14.7 million and no sustaining capital improvements are expected. Table 21-12: Estimated Water Treatment Plant Capital Cost Summary (US$000s) WBS No. Description Initial Capital (US$000s) Sustaining Capital (US$000s) Total Capital (US$000s) 4111 Earthwork $493 $0 $493 4112 Concrete $227 $0 $227 4113 Building $1,411 $0 $1,411 4114 Equipment $7,111 $0 $7,111 4115 Mechanical $1,472 $0 $1,472 4116 Electrical and Instrumentation $2,016 $0 $2,016 4117 Engineering Procurement $192 $0 $192 4118 Construction Management $403 $0 $403 4110 Water Treatment Plant $14,746 $0 $14,746 21.1.7 Raw Water Dam (Tetra Tech) Raw water dam capital costs are based on direct vendor quotes or Tetra Tech in-house estimates, initial capital costs are estimated at US$2.5 million and no sustaining capital improvements are expected. Table 21-13: Estimated Raw Water Dam Capital Cost Summary (US$000s) WBS No. Description Initial Capital (US$000s) Sustaining Capital (US$000s) Total Capital (US$000s) 4121 Site & Foundation Prep $682 $0 $682 4122 Embankment Construction $886 $0 $886 4123 Relocate Outlet Downstream $10 $0 $10 4124 Spillway Construction $271 $0 $271 4125 Other Construction Costs $296 $0 $296 4126 Pump Operation Cost $0 $0 $0 4127 Engineering Procurement $225 $0 $225 4128 Construction Management $92 $0 $92 4129 Temporary Construction Facilities $47 $0 $47 4120 Raw Water Dam $2,509 $0 $2,509

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 296 21.1.8 Tailings Storage Facilities (Tetra Tech) Tailings storage facility capital costs are based on direct vendor quotes or Tetra Tech in-house estimates. Initial capital costs are estimated at US$6.6 million with sustaining capital of US$85 million. Table 21-14: Estimated Tailings Storage Facility Capital Cost Summary (US$000s) WBS No. Description Initial Capital (US$000s) Sustaining Capital (US$000s) Total Capital (US$000s) 4410 TSF 1 1 Site & Foundation Preparation $491 $1,894 $2,386 2 Embankment Construction $226 $4,509 $4,735 3 Downstream Embankment Toe Drain $913 $0 $913 4 Tailings Delivery & Return Pipelines $1,917 $186 $2,103 5 Return Water Ponds $161 $0 $161 6 Diversion Channels $0 $0 $0 7 Equipment Purchase $1,312 $0 $1,312 8 Mobilization $761 $898 $1,660 9 EPCM $837 $988 $1,826 10 Instrumentation $0 $175 $175 4410 TSF 1 $6,618 $8,651 $15,268 4420 TSF 2 1 Site & Foundation Preparation $0 $12,754 $12,754 2 Underdrain Construction $0 $1,218 $1,218 3 Downstream Toe Drain $0 $588 $588 4 Embankment Construction $0 $7,039 $7,039 5 Impoundment Liner $0 $21,449 $21,449 6 Overdrain & Reclaim Sump/Pond Construction $0 $1,689 $1,689 7 Tailings Delivery & Return Pipelines $0 $6,200 $6,200 8 Surface Water Management $0 $1,245 $1,245 9 Equipment Purchase $0 $1,312 $1,312 10 Mobilization $0 $7,371 $7,371 11 EPCM $0 $8,108 $8,108 12 Instrumentation $0 $280 $280 4420 TSF 2 $0 $69,252 $69,252 4400 Tailings Dam $6,618 $77,903 $84,521

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 297 21.2 Operating Costs LoM operating costs requirements are estimated to be US$15.18/t-milled as summarized in Table 21-15. Table 21-15: Estimated LoM Operating Costs (US$) Description US$/t-milled US$/t- moved OPEN PIT MINE Mine General Service 0.10 0.03 Mine Maintenance 0.11 0.03 Engineering 0.05 0.01 Geology 0.03 0.01 Drilling 0.77 0.23 Blasting 1.17 0.35 Loading 0.60 0.18 Hauling 2.74 0.83 Mine Support 0.43 0.13 Mine Dewatering 0.01 0.004 Open Pit Mine 6.02 1.82 CIP PROCESS PLANT Labor 0.79 - 3100-Crush/Screen/Stockpile 0.18 - 3200-Reclaim & HPGR 0.44 - 3300-Classification & Grinding 3.14 - 3400-Pre-Leach,Thick/Aeration/CIP 0.13 - 3500-Desorption, Gold Room 0.02 - 3600-Detox & Tailings Pumping 0.06 - 3700-Reagents 2.98 - 3800-Plant Services 0.04 - Mining, Infrastructure & Misc 0.06 - General Consumables 0.01 - Plant Mobile Equipment 0.01 - Plant Gas Consumption 0.03 - CIP Process Plant 7.88 - Project Services $0.16 - G&A $1.11 - Operating Costs $15.18 -

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 298 21.2.1 Mining (MDA) Annual mine operating costs have been estimated based on personnel requirements and equipment hourly costs. Table 21-16 summarizes annual mine operating costs before the allocation of capitalized mining (capitalized mining is included in Section 21.1.1 – Mining (MDA)). Costs are provided based on functionality (drilling, blasting, loading, hauling, support, mine general services, mine maintenance, engineering, and geology). The following subsections describe the operating cost estimate by functionality. Note that these costs are described before the allocation of costs to capital for pre-stripping, mining of waste for construction purposes, and mining and waste re-handle of material to be used for reclamation. The total average mining cost (open pit to primary crusher only) is estimated to be US$ 1.97/t mined (based on a net operating cost of US$ 1,436 million and 731 million tonnes). Operating costs shown in the economic model reflect operating costs after capitalization. 21.2.1.1 Drilling Costs The average life-of-mine drilling cost is estimated to be US$ 0.24/t mined after allocation of drilling costs for pre-stripping and tailings construction. This includes maintenance allocations based on MARC cost assumptions. 21.2.1.2 Blasting Costs The average life-of-mine blasting cost is estimated to be US$ 0.36/t mined. 21.2.1.3 Loading Costs The average life-of-mine loading cost is estimated to be US$ 0.20/t mined. The cost per tonne moved includes the re-handle of ore and waste from stockpiles at the end of the mine life. Maintenance costs assume the use of MARC costs provided by EMG LLC. 21.2.1.4 Haulage Costs The average life-of-mine haulage cost is estimated to be US$ 0.92/t mined. The cost per tonne moved includes re-handling of stockpiled ore and waste at the end of the mine life. Maintenance costs assume the use of MARC costs provided by EMG LLC. 21.2.1.5 Mine Support Costs Mine-support costs include the operation of all the mine-support equipment. The average life-of-mine support cost is estimated to be US$ 0.15/t mined. The cost per tonne moved includes support during re-handling of stockpiled ore and waste at the end of the mine life. Maintenance costs assume the use of MARC costs provided by EMG LLC. Support costs also include the costs to reinforce the eastern high wall in the ultimate pit with bolts and mesh.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 299 21.2.1.6 Mine Maintenance Costs Most maintenance will be done under a MARC cost structure for pre-production and the first two years of production. Beyond this it was assumed that Vista would take over all maintenance tasks. The vendor with the contract will be expected to supply mechanics and maintenance parts for major equipment repair. Costs associated with the contract have been included in the equipment hourly cost. Prior to the beginning of Year 3, the contractor will provide MARC services, Vista will employ one maintenance planner. After the beginning of Year 3, the MARC costs for the parts and labor were still used for maintenance cost estimates of mining equipment, but the anticipated overhead and profit of the contractor would be removed. For this reason, during Year 3 and beyond, the MARC costs were multiplied by 85%. It was assumed that this will require hiring of a maintenance foreman and an additional maintenance planner. Owner mine-maintenance costs have been included to cover items not covered by the MARC costs, as well as supervision. This includes salaries for a Maintenance Superintendent and Maintenance Planner to track costs associated with the contract. Tiremen will be hired by the owner to maintain all equipment tires, and servicemen will be hired to keep equipment fueled and lubricated. An allocation for shop laborers has been included for light maintenance of facilities. The average life-of-mine mine-maintenance cost is estimated to be US$ 0.04/t mined. This does not include the specific parts and labor allocations to individual equipment, as those costs are allocated to the equipment and the cost center for which the equipment is used. 21.2.1.7 Mine General Services, Engineering and Geology Costs Mine General costs include salaries for a Mine Manager, Mine Clerk, Shift Foremen, and trainers. Mine general costs also include an allocation for various supplies and office costs. Engineering and geology services are provided to maintain surveying, mine planning, and ore control for the operations. The average life-of-mine general services, Engineering, and Geology costs are estimated to be US$ 0.06/t mined.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 300 Table 21-16: Estimated Annual Mine Operating Costs (US$) Units Pre-Prod Yr 1 Yr 2 Yr 3 Yr 4 Yr 5 Yr 6 Yr 7 Yr 8 Yr 9 Yr 10 Yr 11 Yr 12 Yr 13 Yr 14 Total MINED TONNES Ore to Mill k tonnes - 8,836 10,330 17,795 9,232 17,750 8,749 7,178 13,482 17,750 17,750 17,799 127 - - 146,779 Ore to Stkpl k tonnes 2,859 7,302 5,283 6,699 6,354 12,102 235 - - 1,000 10,903 8,172 - - - 60,908 Total Ore Mined k tonnes 2,859 16,138 15,613 24,495 15,586 29,852 8,984 7,178 13,482 18,750 28,653 25,970 127 - - 207,687 Re-handle Ore k tonnes - 3,625 7,420 3 8,518 - 9,001 10,620 1,647 - - - 17,623 15,805 - 74,262 Re-handle Waste k tonnes - 1,555 603 3,848 435 877 - - - - 4,842 6,253 1,171 1,480 7,256 28,324 Re-handle Sorter Rejects k tonnes - - - - - - - - - - - - - - 20,769 20,769 Waste to Dumps k tonnes 8,802 10,498 47,536 32,880 76,531 58,085 87,011 68,218 56,598 42,935 29,747 4,148 - - - 522,990 Total Tonnes Mined k tonnes 11,661 26,636 63,149 57,375 92,117 87,937 95,995 75,396 70,080 61,685 58,400 30,119 127 - - 730,677 Total Tonnes Moved k tonnes 11,661 31,816 71,172 61,226 101,070 88,814 104,996 86,016 71,727 61,685 63,242 36,372 18,921 17,285 28,025 854,032 Strip Ratio w:o 3.08 0.65 3.04 1.34 4.91 1.95 9.69 9.50 4.20 2.29 1.04 0.16 - 2.52 Mined Waste to Construction k tonnes 675 150 6,381 1,956 3,741 1,820 4,275 3,218 6,592 - 1,496 24 - - - 30,328 Mined Material for Pre-Production k tonnes 122 - - - - - - - - - - - - - - 122 Mined Waste for Closure k tonnes - - - - - - - - - - - - - 1,480 7,256 8,740 Net Tonnage Mined k tonnes 10,864 28,041 57,371 59,266 88,811 86,994 91,720 72,178 63,488 61,685 61,746 36,348 1,298 - - 719,811 MINING COSTS Mine General Service K USD $ 689 $ 1,611 $ 1,618 $ 1,705 $ 1,966 $ 1,966 $ 1,966 $ 1,971 $ 1,966 $ 1,966 $ 1,966 $ 1,615 $ 1,257 $ 1,225 $ 919 $ 24,402 Mine Maintenance K USD $ 796 $ 1,592 $ 1,592 $ 2,138 $ 2,198 $ 2,198 $ 2,198 $ 2,204 $ 2,198 $ 2,198 $ 2,198 $ 2,204 $ 2,198 $ 1,380 $ 1,093 $ 28,381 Engineering K USD $ 348 $ 912 $ 912 $ 915 $ 912 $ 912 $ 912 $ 915 $ 912 $ 912 $ 912 $ 915 $ 502 $ 678 $ 376 $ 11,946 Geology K USD $ 316 $ 628 $ 628 $ 629 $ 628 $ 628 $ 628 $ 629 $ 628 $ 628 $ 628 $ 629 $ 628 $ 195 $ 38 $ 8,087 Drilling K USD $ 2,805 $ 8,094 $ 15,344 $ 14,784 $ 19,926 $ 21,416 $ 19,657 $ 15,465 $ 15,475 $ 14,793 $ 15,814 $ 9,858 $ 139 $ 0 $ 0 $ 173,570 Blasting K USD $ 4,294 $ 10,852 $ 22,473 $ 21,674 $ 31,737 $ 32,085 $ 32,198 $ 25,395 $ 24,437 $ 22,344 $ 22,451 $ 13,119 $ 460 $ 0 $ 0 $ 263,518 Loading K USD $ 2,127 $ 6,058 $ 13,229 $ 10,612 $ 17,288 $ 15,051 $ 18,054 $ 15,206 $ 12,187 $ 10,624 $ 10,968 $ 6,585 $ 3,383 $ 3,140 $ 4,882 $ 149,394 Hauling K USD $ 5,183 $ 17,928 $ 41,984 $ 40,377 $ 63,515 $ 65,485 $ 69,394 $ 71,253 $ 77,754 $ 75,383 $ 77,008 $ 41,148 $ 6,400 $ 6,133 $ 10,623 $ 669,572 Mine Support K USD $ 2,642 $ 5,062 $ 6,756 $ 7,044 $ 7,264 $ 8,046 $ 11,867 $ 11,113 $ 10,951 $ 10,357 $ 9,333 $ 6,204 $ 3,846 $ 3,811 $ 2,836 $ 107,131 Total Mine Cost K USD $ 19,201 $ 52,736 $ 104,540 $ 99,889 $ 145,431 $ 147,816 $ 156,852 $ 144,128 $ 146,535 $ 139,241 $ 141,292 $ 82,270 $ 18,826 $ 16,576 $ 20,748 $ 1,436,096 MINE COST PER TONNE MINED Mine General Service $ /t $ 0.06 $ 0.06 $ 0.03 $ 0.03 $ 0.02 $ 0.02 $ 0.02 $ 0.03 $ 0.03 $ 0.03 $ 0.03 $ 0.05 $ 9.88 $ 0 $ 0 $ 0.03 Mine Maintenance $ /t $ 0.07 $ 0.06 $ 0.03 $ 0.04 $ 0.02 $ 0.02 $ 0.02 $ 0.03 $ 0.03 $ 0.04 $ 0.04 $ 0.07 $ 17.29 $ 0 $ 0 $ 0.04 Engineering $ /t $ 0.03 $ 0.03 $ 0.01 $ 0.02 $ 0.01 $ 0.01 $ 0.01 $ 0.01 $ 0.01 $ 0.01 $ 0.02 $ 0.03 $ 3.95 $ 0 $ 0 $ 0.02 Geology $ /t $ 0.03 $ 0.02 $ 0.01 $ 0.01 $ 0.01 $ 0.01 $ 0.01 $ 0.01 $ 0.01 $ 0.01 $ 0.01 $ 0.02 $ 4.94 $ 0 $ 0 $ 0.01 Drilling $ /t $ 0.24 $ 0.30 $ 0.24 $ 0.26 $ 0.22 $ 0.24 $ 0.20 $ 0.21 $ 0.22 $ 0.24 $ 0.27 $ 0.33 $ 1.09 $ 0 $ 0 $ 0.24 Blasting $ /t $ 0.37 $ 0.41 $ 0.36 $ 0.38 $ 0.34 $ 0.36 $ 0.34 $ 0.34 $ 0.35 $ 0.36 $ 0.38 $ 0.44 $ 3.62 $ 0 $ 0 $ 0.36 Loading $ /t $ 0.18 $ 0.23 $ 0.21 $ 0.18 $ 0.19 $ 0.17 $ 0.19 $ 0.20 $ 0.17 $ 0.17 $ 0.19 $ 0.22 $ 26.61 $ 0 $ 0 $ 0.20 Hauling $ /t $ 0.44 $ 0.67 $ 0.66 $ 0.70 $ 0.69 $ 0.74 $ 0.72 $ 0.95 $ 1.11 $ 1.22 $ 1.32 $ 1.37 $ 50.34 $ 0 $ 0 $ 0.92 Mine Support $ /t $ 0.23 $ 0.19 $ 0.11 $ 0.12 $ 0.08 $ 0.09 $ 0.12 $ 0.15 $ 0.16 $ 0.17 $ 0.16 $ 0.21 $ 30.25 $ 0 $ 0 $ 0.15 Total Mine Cost $ /t $ 1.65 $ 1.98 $ 1.66 $ 1.74 $ 1.58 $ 1.68 $ 1.63 $ 1.91 $ 2.09 $ 2.26 $ 2.42 $ 2.73 $ 147.97 $ 0 $ 0 $ 1.97

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 301 21.2.2 Mine Dewatering (Tetra Tech) Operating costs are related to power consumption of pumps; labor is excluded, as supervision of the dewatering system is planned for existing mine or environmental staff and will not require dedicated personnel. Mine dewatering estimated operating costs average US$0.012/t-milled. 21.2.3 CIP Process and G&A (TTP) Please note that this Section describes costs in Australian Dollars (AUD). Overall the approach taken for the PFS operating cost estimate establishment was to perform the estimates at a FS level of detail, leading to a higher than usual level of detail presented for the Technical Report. This approach was deliberately adopted to minimize rework during the FS stage, with additional information expected to be limited to the use of improved accuracy quotes for the FS cost estimate. Final plant operating cost estimates issued for the Technical Report were AUD217 million per year, giving a cost of AUD 12.24/t treated as shown in Table 21-17. 21.2.3.1 Cost Distribution The distribution of operating costs was not unexpected for large scale gold operations, with the five main operating cost expenditures in descending order being: „ Reagents and Consumables; „ Power; „ Labor; „ Maintenance; and „ G&A. Items of expenditure higher than normally expected for gold mining operations related specifically to: „ Ore hardness, and included consumables (mill media) and power consumption; and „ High volume / low grade ore treatment schedule and related predominantly to reagents. Table 21-17: Estimated Plant Operating Costs (@ Steady State) (AUD) Cost Center Operating Cost AUD/ a AUD/ t AUD/oz % LABOR Total 28,640,000 1.61 63.83 13.2% TRANSPORT & ACCOMMODATION Total 1,810,000 0.10 4.03 0.8% POWER Processing Plant 48,170,000 2.71 Miscellaneous 570,000 0.03 Total 48,740,000 2.75 108.63 22.4%

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 302 Cost Center Operating Cost AUD/ a AUD/ t AUD/oz % FUEL Vehicles 420,000 0.02 Plant Gas 710,000 0.04 Total 1,130,000 0.06 2.52 0.5% MAINTENANCE Fixed Plant 11,370,000 0.64 Mobile Equipment 150,000 0.01 Total 11,520,000 0.65 25.67 5.3% REAGENTS & CONSUMABLES Reagent 75,810,000 4.27 Consumables 45,860,000 2.58 Total 121,670,000 6.85 271.16 56.0% EQUIPMENT HIRE Total 0 0.00 0.00 0.0% PRODUCT TRANSPORT Total 0 0.00 0.00 0.0% CONTRACT – GENERAL EXPENSES GENERAL CONSUMABLES 260,000 0.01 CONTRACT EXPENSES 910,000 0.05 GENERAL EXPENSES 2,530,000 0.14 MINING CONTRACT 0 0.00 Total 3,700,000 0.21 8.25 1.7% TOTAL AUD 217,210,000 12.24 484.09 100% 21.2.3.2 Labor Estimated labor costs were developed by a build-up of base labor rates, on-costs and required work force numbers. Workforce numbers were developed using a bottom-up approach by assessing requirements in each area, and in consultation with Vista personnel, adjusting for areas specific to Mt Todd requirements. Labor rates were initially taken as the TTP standard rates (actual operating mine data from 2010), but were subsequently adjusted up by 7% in consultation with Vista. A review was conducted by recruitment consultant Michael Page, which indicated labor rates for 4 out of the 154 categories presented required an upwards adjustment. Labor rates have since been revised, based on recently completed projects (2017 & 2018/19) and industry consultation.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 303 The whole site labor force was presented in the TTP operating cost analysis to ensure that there was some consistency in labor rates across the board, however mining and mining related labor costs were not included in the TTP operating cost estimate as these costs were ultimately in the domain of the mining consultant MDA’s operating cost schedule. Final process plant and general and administrative (G&A) labor cost estimates issued for the Technical Report were AUD28.64 million per year. 21.2.3.3 Transport and Accommodation ACCOMMODATION COST DEVELOPMENT Taking on board the Vista model for labor force accommodation of a workforce self-funded housing scheme based in Katherine and Pine Creek, the requirements for on-going use of any camp post the construction period was estimated as follows: „ Accommodation allowance to cover personnel recruitment, assuming a 20% turnover of the entire workforce annually, and assuming these personnel would consist of a four unit family requiring accommodation in the camp for an average of 2 months before sourcing their own accommodation. This provided an estimated requirement for 54 rooms in the camp per annum. „ Accommodation for contractors flying to site, largest of which would predominantly consist of the mill reline crew. Assuming a nominal sum of 10 other contractors throughout the year, and assuming these could be staggered to require accommodation for periods other than during mill relines, gave an estimated requirement for an additional 18 rooms. „ Accommodation for miscellaneous visitors, etc. where accommodation for whatever reason could not be mutually exclusive with mill relines provided a nominal requirement for 7 rooms. „ For the total on-going accommodation estimate of 69 rooms per annum, a requirement for 70 rooms was anticipated. An allowance of AUD62.99 per man per day was made for a continuation of the partial construction camp. TRANSPORT COST DEVELOPMENT Using the numbers developed for the accommodation requirement, flights to Darwin from Perth were estimated at 225 return flights per annum. Allowing a 42% / 17% / 42% split between Low, Shoulder and High seasons respectively, and assuming all flights were at fully flexible fares provided the basis for annual flight expenditures. TRANSPORT AND ACCOMMODATION COSTS Final transport and accommodation cost estimates issued for the Technical Report were AUD1.810 million per year.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 304 21.2.3.4 Power Requirements Power usage was developed by a combination of methods, namely: „ Significant power consuming items had power consumptions calculated from base formulae and models, and included the following items: ⎯ Primary crusher; ⎯ Secondary crushers; ⎯ Ball mills; ⎯ Secondary Mills; and ⎯ HPGR Units. „ For smaller or steady state power consumers the power consumed was calculated as a factor of installed power, with the factor varying on known vendor motor oversizing propensities. „ Nominal allowances were made for some areas where actual installed power was estimated based on usual loads for such duties, and included items such as the air conditioners, lighting and small power, etc. The total estimated power consumption is approximately 649 GWh/year. 21.2.3.5 Fuel Fuel consumption estimates were developed for each item of process plant mobile equipment, by estimating annual operating hours and using vendor documented or estimated fuel consumptions for each equipment item. Other plant items usually consuming fuel, namely power generation, product drying, borefield, etc. were all zero for the Mt Todd proposed operating plant. 21.2.3.6 Maintenance Maintenance costs were developed by applying factors to FIS equipment costs for each of the two OPEX cases. The TTP maintenance cost estimating methodology is consistent with that of the Australasian Institute of Mining and Metallurgy (Cost Estimation Handbook for the Australian Mining Industry, AUSIMM, 1993). TTP factors have been developed over a period of time and fall within the AUSIMM guidelines. Large wear items (crusher wear liners, ball mill lifters / liners) were identified and listed separately in the consumables section. An additional allowance of 1.5% was applied across the site equipment to allow for sustaining capital expenditure. Maintenance cost estimates issued for the Technical Report were AUD11.520 million per year. 21.2.3.7 Reagents Reagent costs were estimated by applying the ALS-determined consumption rates with a quoted cost of delivered reagents to site. Instances where consumption rates were altered from the original ALS testwork or previous assumptions included: „ Consumption of carbon was increased from 15 g/t to 20g/t based on industry experience.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 305 „ Flocculant consumption was changed to 40 g/t for the Pre-Leach thickener based on recent test work. „ Sodium Cyanide changed to 876 g/t (leach feed) and Quick Lime increased to 2,800 g/t (leach feed) based on recent test work and the removal of the tailing’s thickener. Reagent prices were obtained from quotes from relevant suppliers. For the Technical Report only one vendor quote for the majority of reagents was available, with multiple additional quotes still pending. Multiple suppliers were engaged for the highest expenditure reagent (sodium cyanide), with an Australian supplier chosen as the most cost-effective supplier. Further price sourcing from overseas suppliers was on- going at the time of writing. Transport costs of reagents to site were sourced from reagent suppliers, in addition to an independent quote from a transport agency. The cheapest of the quotes for delivery from Darwin to Katherine was chosen as the cost to be used in the Technical Report, in this case it was from Seatram. Reagent cost estimates issued for the Technical Report were AUD75.810 million per year. 21.2.3.8 Consumables Consumable costs were estimated by calculating or estimate consumable consumption rates coupled with quotes or estimates for unit prices. Consumption of mill balls was estimated by the selected mill vendor and based on the ore abrasion index, and since this item was one of the largest expenditures in the consumable category three quotes were received, with the most cost effective being Shandong Humain (China) Where possible, transport costs were sourced from suppliers, however if they were not provided costs were sourced from other quotes. The quote from Shandong Huamin only included shipping to Darwin. Transport costs from Darwin to Katherine were sourced from the Molycorp quote. In some instances where vendor advice was not received in a timely fashion, consumable quotes were scaled from previous studies. Consumable cost estimates issued for the Technical Report were AUD45.860million per year. 21.2.3.9 Equipment Hire The Vista requirement to minimize upfront capital costs was used as the basis to initially assume all process plant mobile equipment, all process plant light vehicles and general site vehicles (ambulance, bus, coaches, etc.) would be hired or leased rather than purchased outright. The overall cost effectiveness of the lease decision was further analyzed with the ultimate decision to purchase the vehicles outright. Consequently, the equipment hire operating costs reverted to zero, with the purchase costs then added to the capital costs. With all plant vehicles then treated as fully owned, an allowance was added for vehicle maintenance.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 306 21.2.3.10 Contract/General Expenses TTP standard factors were used for general expenses and general consumables, some items of which are a standard allowance and others which are linked to site personnel numbers (clothing, medical supplies, etc.). General expenses and consumables allowed for included: „ General Consumables; Office and General Supplies, Tools and Equipment, Communications Maintenance Materials, Sampling and Analysis Consumables „ Contract Expenses; Environmental Monitoring Costs, Contracting Electrical Expenses „ General Expenses; Emergency Supply, Personnel Recruitment, Legal/Compliance, Office Communications, Safety Supplies TTP’s standard allowances were included for contract expenses, with the adjustments specific for Mt Todd including: „ Additional allowances for environmental monitoring costs as advised by Vista „ Additional contract electrical costs to allow for the complexity of interaction and maintaining dual source High Voltage power supplies General / Contract Expenses in addition to General Consumables cost estimates issued for the Technical Report were $3.700 million per year. 21.2.4 Power Plant (POWER Engineers) Please note that this Section describes costs in Australian Dollars (AUD). 21.2.4.1 Fuel Costs Fuel cost analysis is based on baseload operation of the power station calculated using generating equipment Higher Heating Value (HHV) heat rates operating at the manufacturer standard conditions (37°C and 38% relative humidity). Table 21-18 lists the fuel gas requirements for the Jenbacher J920 reciprocating engines. Table 21-18: Estimated Fuel Cost Summary (AUD) Description GE Jenbacher J920 (Seven) (AUD) Gross Output (kW) 72,709 Net Output (kW) 71,255 Plant Required Average Output (kW) 69,664 Auxiliary Loads (kW) 1,454 Availability 99.9% HHV Net Heat Rate (kJ/kWh) 8,961 Thermal Efficiency 44.47% Annual Fuel Gas Consumption (GJ/yr) 5,253,349

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 307 Description GE Jenbacher J920 (Seven) (AUD) Annual Fuel Cost for Base Load (AUD/yr) $36,773,445 Pipeline toll fees (AUD/yr) $3,152,010 More than 80% of the costs associated with the power station operation can be attributed to fuel costs with the remainder being scheduled maintenance and replacement parts. Properly maintained reciprocating gas engines can operate up to 80,000 hours (approximately 9 years) between major engine block overhauls with annual inspections and general maintenance. Annual maintenance and inspections consist of functional checks and parts replacement of the lubricating oil and filters, inlet air filters, combustion system (spark plugs), and cooling system inspection. Minor maintenance occurs at the 20,000- and 40,000-hour intervals. Minor maintenance consists of inspection and possible replacement of bearings, cylinder heads/liners, pistons, couplings, and turbocharger components. It is anticipated that engine maintenance will be sequenced such that only a single engine is down at any time for maintenance to avoid plant disruption. Operating costs include a minimal staff dedicated to the power station and will be based in the Administration Building. Personnel staff will consist of three swing shifts, at two operators per 12-hour shift, with a mechanic and instrumentation/electrical technician on one shift per day. One of the day shift operators can also serve as the control room manager. Labor rates are provided by Vista and include 27% salary on-costs. Plant personnel costs are shown in Table 21-19. Table 21-19: Estimated Personnel Costs, Power Plant (AUD) Annual Salary (AUD) Number on Staff Power & Water Superintendent $193,040 1 Power Station Operator $115,570 5 Instrumentation/Electrical Technician $154,940 1 Mechanic $154,940 1 Total $1,080,770 8 Table 21-20 lists the annual operating costs for the GE Jenbacher J920 gas engines to generate a nominal net output of 69.6MW, as required by the 50,000 tpd operation for the 20-year life of the mining project. This estimate includes operating overhead personnel to meet the mine’s base power demand. Engine maintenance costs are estimated to be AUD0.0129 AUD/kWh, which are typical costs for reciprocating engine maintenance with a full maintenance contract (NREL, GRI, 2013). In addition, the engine maintenance costs include the cost associated with purchasing power from the utility grid during engine maintenance downtime. The power plant was estimated on a 20-year life to account for pre-production, production, and closure operations, which is approximately 19 years, and then rounded to 20 years of life to estimate the value for determination of sale at the planned end of mine life.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 308 Table 21-20: Estimated Gas Turbine Maintenance Cost Schedule – 70MW (AUD) Year Engine Fuel Costs (AUD) Engine Maintenance Costs (AUD) On-Site Personnel (AUD) 1 $36,773,445 $13,584,342 $1,080,770 2 $36,773,445 $13,584,342 $1,080,770 3 $36,773,445 $13,584,342 $1,080,770 4 $36,773,445 $13,584,342 $1,080,770 5 $36,773,445 $13,584,342 $1,080,770 6 $36,773,445 $13,584,342 $1,080,770 7 $36,773,445 $13,584,342 $1,080,770 8 $36,773,445 $13,584,342 $1,080,770 9 $36,773,445 $13,584,342 $1,080,770 10 $36,773,445 $13,584,342 $1,080,770 11 $36,773,445 $13,584,342 $1,080,770 12 $36,773,445 $13,584,342 $1,080,770 13 $36,773,445 $13,584,342 $1,080,770 14 $36,773,445 $13,584,342 $1,080,770 15 $36,773,445 $13,584,342 $1,080,770 16 $36,773,445 $13,584,342 $1,080,770 17 $36,773,445 $13,584,342 $1,080,770 18 $36,773,445 $13,584,342 $1,080,770 19 $36,773,445 $13,584,342 $1,080,770 20 $36,773,445 $13,584,342 $1,080,770 Subtotal $735,468,900 $271,686,840 $21,615,400 TOTAL $1,028,771,140 21.2.5 Water Treatment Plant (Tetra Tech) Water treatment plant operating costs averaging US$0.09/t-milled. 21.2.6 Tailings Storage Facilities (Tetra Tech) Tailings operating costs are estimated to average US$0.07/t-milled over the LoM. Tailings operating costs include shaping and compaction of the mine waste in the tailings embankments that hauled as a mining cost. Pumping and power costs for tailings facility operation are included in the Process Plant costing. 21.2.7 General & Administrative G&A is estimated to be an average of US$1.11/t-milled over the LoM.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 309 22.0 ECONOMIC ANALYSIS Project economics for the 50,000 tpd operation are based on inputs developed by MDA, TTP, POWER Engineers and Tetra Tech. Economic results presented in the report suggest the following conclusions, assuming a 100% equity project: „ Mine Life: 13 years; „ Pre-Tax NPV5%: US$1,440 million, IRR: 30.4%; „ After-tax NPV5%: US$823 million, IRR: 23.4%; „ Payback (After-tax): 2.9 years; „ NT Royalty Paid: US$473 million; „ Australian Income Taxes Paid: US$553 million; and „ Cash costs (including JAAC Royalty): US$645.14/oz-Au. After-tax net present value (NPV) is US$823 million, discounted at 5%. The after-tax internal rate of return (IRR) for the Project is 23.4%. Costs and economic results are presented in Q3 2019 U.S. dollars unless otherwise stated. No escalation has been applied to capital or operating costs. The 5% discount rate used is a gold industry norm. Technical economic tables and figures presented in this volume require subsequent calculations to derive subtotals, totals, and weighted averages. Such calculations inherently involve a degree of rounding. Where these occur they are not considered to be material. 22.1 Principal Assumptions Parameters used in the analysis are shown in Table 22-1. These parameters are based upon current market conditions, vendor quotes, design criteria developed by Vista and their consultants, and benchmarks against similar existing projects. Table 22-1: TEM Principal Assumptions Principal Assumptions Unit Parameter Construction Period Years 2 Commissioning & Ramp-Up Years 0.5 Mine Life Years 13 Closure Period Years 4 Operating Days Days / Year 355 Gold Price US$ $1,350 JAAC Royalty % 1% Exchange Rate AUD:US$ 0.7:1 Diesel Fuel AUD/L $0.850 Natural Gas AUD/GJ $7.00 Electric Power – From Grid AUD/kWh $0.300 Electric Power – From Plant AUD/kWh $0.076

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 310 The Project will commence at a production rate of 50,000 tpd. Fresh ore production will originate from the open pit mine and will be treated using conventional CIP technology. Once ore is exhausted from the pit, the reserves in the existing heap leach pad will then be processed. Projected revenues from the sale of gold doré are based upon a market price of US$1,350/oz-Au. Vista has used indicative pricing from the Perth Mint for the sale of its product. It is too early to enter into definitive agreement with refiners as of the date of this Technical Report. However, refinery assumptions used in the technical economic model (TEM) are indicative of current refiner rates. Refining costs are summarized in Table 22-2 resulting in an all-in refining cost of US$3.22/Au-oz over the LoM. Table 22-2: Estimated Refining Costs (US$) Cost Component Units Cost (US$) Refining Fee $/oz 0.75 Gold Retention % of gold sales 0.10% Purchase Discount-Gold $/oz 0.50 Assay Fee $/oz 95.00 Environmental Fee $/oz 50.00 Freight & Insurance $/oz 0.20 The Project is subject to a 20% net value-based mineral royalty imposed by the Norther Territory Government and the Commonwealth corporate income tax based on 30% of taxable income. The NT Royalty is among deductions permitted in determining taxable income. 22.2 LoM Production Ore will be mined using open pit mining methods. Production over the LoM is summarized in Table 22-3. Table 22-3: LoM Ore Production Production kt g/t Contained Au (koz) Waste 522,990 - - Ore 207,687 0.84 5,616 Heap Leach 13,354 0.54 232 Total Production* 221,041 0.82 5,848 *Total production excludes waste tonnes. The Project has been planned as an open-pit truck and shovel operation. Open pit ore totals 208 Mt grading 0.84 g/t and contains 5.6 Moz of gold. Open pit production will have a 2.5:1 strip ratio over the 13-year LoM. Upon completion of conventional mining, the existing heap leach pad will be processed.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 311 Ore is planned to be processed in a large comminution circuit consisting of a gyratory crusher, two cone crushers, two HPGR crushers, and two primary ball mills followed by 10 FLS VXP mills for secondary grinding as discussed in Section 17.0 – Recovery Methods. Vista plans to recover gold in a conventional carbon-in- pulp (“CIP”) recovery circuit. Process recovery was determined based on ore types. Three ore types, sulfide, mixed, and oxide were identified for the open pit and will have recoveries of 92.9%, 91.8%, and 91.5%, respectively. The heap leach pad will have a recovery of 90.7%. An additional 1% for net solution loss is applied to all the deposits and heap leach which results in a LoM average recovery of 91.9%.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 312 22.3 Capital Costs LoM capital cost requirements are estimated at US$1,222 million as summarized in Table 22-4. Initial capital of US$826 million is estimated to be required to commence operations. Sustaining capital of US$397 million is required over the LoM and accounts for capitalized stripping in the open pit, mine equipment additions and replacements, and tailings dam raises. Table 22-4: Estimated LoM Capital Costs (US$000s) Area Description Cont. (%) Initial Capital (US$000s) Sustaining Capital (US$000s) Total Capital (US$000s) Estimate Contingency Total Estimate Contingency Total Estimate Contingency Total 2000 Mining 7.3% $121,239 $5,720 $126,958 $406,347 $32,677 $439,024 $527,586 $38,396 $565,982 3000 Process Plant 13.9% $366,693 $51,073 $417,766 $17,027 $2,222 $19,249 $383,720 $53,295 $437,016 4000 Project Services 10.0% $109,204 $12,681 $121,885 $72,448 $5,455 $77,903 $181,651 $18,136 $199,787 5000 Project Infrastructure 13.2% $26,160 $3,463 $29,623 $0 $0 $0 $26,160 $3,463 $29,623 6000 Permanent Accommodation 10.0% $60 $6 $66 $0 $0 $0 $60 $6 $66 7000 Site Establishment & Early Works 11.4% $17,537 $1,995 $19,532 $0 $0 $0 $17,537 $1,995 $19,532 8000 Management, Engineering, EPCM Svcs 11.8% $82,058 $9,721 $91,779 $0 $0 $0 $82,058 $9,721 $91,779 9000 Pre-Production Costs 12.3% $16,121 $1,982 $18,102 $0 $0 $0 $16,121 $1,982 $18,102 10000 Asset Sale 0.0% $0 $0 $0 ($139,631) $0 ($139,631) ($139,631) $0 ($139,631) Capital Cost 11.6% $739,072 $86,641 $825,712 $356,191 $40,354 $396,545 $1,095,263 $126,994 $1,222,257

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 313 22.3.1 2000 Mining LoM capital cost requirements are estimated to value US$566 million with an initial cost of US$127 million as seen in Table 22-25. Table 22-5: Estimated Mining Costs (US$000s) Area Description Cont. (%) Initial Capital (US$000s) Sustaining Capital (US$000s) Total Capital (US$000s) Estimate Contingency Total Estimate Contingency Total Estimate Contingency Total 2000 MINING 2100 Capitalized Mine Operating 10.0% $19,201 $1,920 $21,121 $88,522 $8,852 $97,374 $107,722 $10,772 $118,494 2200 Mine Production Equipment 2.9% $91,116 $2,629 $93,745 $196,415 $5,667 $202,083 $287,531 $8,296 $295,827 2300 Mine Support Facilities 9.0% $8,762 $787 $9,548 $906 $81 $988 $9,668 $868 $10,536 2400 Mine Support Services 20.0% $1,195 $239 $1,434 $0 $0 $0 $1,195 $239 $1,434 2500 Mine Dewatering/Drainage 15.0% $858 $129 $987 $411 $62 $473 $1,269 $190 $1,459 2900 Mine Closure 15.0% $108 $16 $124 $120,094 $18,014 $138,108 $120,201 $18,030 $138,232 Mining 7.3% $121,239 $5,720 $126,958 $406,347 $32,677 $439,024 $527,586 $38,396 $565,982 22.3.2 3000 Process Plant Estimated CIP process plant capital costs are shown in Table 22-6. Initial capital totaling US$418 million is estimated to be required for the CIP process plant; a total capital of US$437 million is required. Table 22-6: Estimated CIP Process Plant Capital Costs (US$000s) Area Description Cont. (%) Initial Capital (US$000s) Sustaining Capital (US$000s) Total Capital (US$000s) Estimate Contingency Total Estimate Contingency Total Estimate Contingency Total 3000 PROCESS PLANT 3100 Crushing & Screening 13.7% $44,878 $6,141 $51,019 $2,168 $297 $2,464 $47,046 $6,438 $53,483 3200 Coarse Ore Stockpile, Reclaim, HPGR 13.9% $84,151 $11,683 $95,834 $4,644 $645 $5,288 $88,794 $12,328 $101,122 3300 Classification & Grinding 12.3% $96,862 $11,905 $108,767 $7,208 $886 $8,094 $104,069 $12,791 $116,860 3400 Pre-leach Thickening, Leach & CIP 12.7% $59,623 $7,555 $67,179 $1,499 $190 $1,689 $61,122 $7,745 $68,868

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 314 Area Description Cont. (%) Initial Capital (US$000s) Sustaining Capital (US$000s) Total Capital (US$000s) Estimate Contingency Total Estimate Contingency Total Estimate Contingency Total 3500 Desorption & Goldroom 13.4% $8,067 $1,077 $9,144 $891 $119 $1,010 $8,958 $1,196 $10,154 3600 Detoxification & Tailings 15.3% $7,765 $1,185 $8,950 $335 $51 $386 $8,100 $1,236 $9,336 3700 Reagents 10.0% $10,317 $1,035 $11,352 $209 $21 $230 $10,526 $1,056 $11,583 3800 Process Plant Services 19.1% $55,031 $10,491 $65,521 $74 $14 $88 $55,105 $10,505 $65,609 Process Plant 13.9% $366,693 $51,073 $417,766 $17,027 $2,222 $19,249 $383,720 $53,295 $437,016 22.3.3 4000 Project Services Project services are estimated to have a LoM capital value US$200 million, with an initial capital value of US$122 million. Table 22-7: Estimated Project Services Capital Costs (US$000s) Area Description Cont. (%) Initial Capital (US$000s) Sustaining Capital (US$000s) Total Capital (US$000s) Estimate Contingency Total Estimate Contingency Total Estimate Contingency Total 4000 PROJECT SERVICES 4100 Water Distribution & Water Treatment Plant 14.0% $17,783 $2,486 $20,269 $0 $0 $0 $17,783 $2,486 $20,269 4200 Power Supply 11.6% $81,679 $9,457 $91,137 $0 $0 $0 $81,679 $9,457 $91,137 4300 Communications 15.9% $644 $102 $746 $0 $0 $0 $644 $102 $746 4400 Tailings Dams 1 & 2 7.5% $6,154 $463 $6,618 $72,448 $5,455 $77,903 $78,602 $5,918 $84,521 4500 Waste Disposal 15.0% $250 $37 $287 $0 $0 $0 $250 $37 $287 4600 Plant Mobile Equipment 5.0% $2,693 $135 $2,828 $0 $0 $0 $2,693 $135 $2,828 4800 Fuel Storage & Distribution (Plant) 0.0% $0 $0 $0 $0 $0 $0 $0 $0 $0 4900 Project Services - Closure 0.0% $0 $0 $0 $0 $0 $0 $0 $0 $0 Project Services 10.0% $109,204 $12,681 $121,885 $72,448 $5,455 $77,903 $181,651 $18,136 $199,787

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 315 22.3.4 5000 Project Infrastructure The total project infrastructure is estimated to value US$30 million, which consists only of initial costs, no sustaining capital is expected. A detailed outline of costs is shown in Table 22-8. Table 22-8: Estimated Project Infrastructure Capital Costs (US$000s) Area Description Cont. (%) Initial Capital (US$000s) Sustaining Capital (US$000s) Total Capital (US$000s) Estimate Contingency Total Estimate Contingency Total Estimate Contingency Total 5000 PROJECT INFRASTRUCTURE 5100 Site Preparation 13.8% $17,997 $2,483 $20,480 $0 $0 $0 $17,997 $2,483 $20,480 5200 Support Buildings 10.1% $4,256 $431 $4,687 $0 $0 $0 $4,256 $431 $4,687 5300 Access Roads, Parking & Laydown 10.0% $740 $74 $814 $0 $0 $0 $740 $74 $814 5400 Heavy Lift Cranage 15.0% $2,062 $309 $2,371 $0 $0 $0 $2,062 $309 $2,371 5500 TBA 0.0% $0 $0 $0 $0 $0 $0 $0 $0 $0 5600 Bulk Transport 15.0% $396 $59 $455 $0 $0 $0 $396 $59 $455 5700 Power Transmission 0.0% $0 $0 $0 $0 $0 $0 $0 $0 $0 5800 Communications 15.0% $710 $106 $816 $0 $0 $0 $710 $106 $816 Project Infrastructure 13.2% $26,160 $3,463 $29,623 $0 $0 $0 $26,160 $3,463 $29,623 22.3.5 6000 Permanent Accommodation Total capital for Permanent Accommodations values at US$66 thousand as shown in Table 22-9. Table 22-9: Estimated Permanent Accommodation Costs (US$000s) Area Description Cont. (%) Initial Capital (US$000s) Sustaining Capital (US$000s) Total Capital (US$000s) Estimate Contingency Total Estimate Contingency Total Estimate Contingency Total 6000 PERMANENT ACCOMMODATION 6100 Permanent Accommodation 10.0% $60 $6 $66 $0 $0 $0 $60 $6 $66 Permanent Accommodation 10.0% $60 $6 $66 $0 $0 $0 $60 $6 $66

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 316 22.3.6 7000 Site Establishment & Early Works Site Establishment and early works capital costs are estimated to total US$20 million over the LoM as shown in Table 22-10. These costs occur in pre- production. Table 22-10: Estimated Site Establishment & Early Works (US$000s) Area Description Cont. (%) Initial Capital (US$000s) Sustaining Capital (US$000s) Total Capital (US$000s) Estimate Contingency Total Estimate Contingency Total Estimate Contingency Total 7000 SITE ESTABLISHMENT & EARLY WORKS 7300 Construction Camp 11.4% $17,537 $1,995 $19,532 $0 $0 $0 $17,537 $1,995 $19,532 7400 Dewatering 0.0% $0 $0 $0 $0 $0 $0 $0 $0 $0 7500 Demolition & Removal 0.0% $0 $0 $0 $0 $0 $0 $0 $0 $0 Site Establishment & Early Works 11.4% $17,537 $1,995 $19,532 $0 $0 $0 $17,537 $1,995 $19,532 22.3.7 8000 Management, Engineering, EPCM Services Management, engineering, and EPCM services are estimated to value US$92 million. These costs are shown in Table 22-11. Table 22-11: Estimated Management, Engineering, EPCM Services (US$000s) Area Description Cont. (%) Initial Capital (US$000s) Sustaining Capital (US$000s) Total Capital (US$000s) Estimate Contingency Total Estimate Contingency Total Estimate Contingency Total 8000 MANAGEMENT, ENGINEERING, EPCM SVCS 8100 EPCM Services 9.7% $42,177 $4,076 $46,253 $0 $0 $0 $42,177 $4,076 $46,253 8200 External Consulting & Testing 20.0% $840 $168 $1,008 $0 $0 $0 $840 $168 $1,008 8300 Commissioning 16.4% $4,472 $734 $5,206 $0 $0 $0 $4,472 $734 $5,206 8400 Owner's Engineering & Management 12.9% $30,547 $3,939 $34,486 $0 $0 $0 $30,547 $3,939 $34,486 8800 License, fees & Legal Services 20.0% $2,011 $402 $2,413 $0 $0 $0 $2,011 $402 $2,413 8900 Project Insurance 20.0% $2,011 $402 $2,413 $0 $0 $0 $2,011 $402 $2,413 Management, Engineering, EPCM Svcs 11.8% $82,058 $9,721 $91,779 $0 $0 $0 $82,058 $9,721 $91,779

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 317 22.3.8 9000 Pre-Production Costs Pre-production capital values US$18 million as shown in Table 22-12. This cost will occur pre-preproduction. Table 22-12: Estimated Pre-Production Costs (US$000s) Area Description Cont. (%) Initial Capital (US$000s) Sustaining Capital (US$000s) Total Capital (US$000s) Estimate Contingency Total Estimate Contingency Total Estimate Contingency Total 9000 PRE-PRODUCTION COSTS 9100 PPD Labor 20.0% $1,005 $201 $1,206 $0 $0 $0 $1,005 $201 $1,206 9200 Commissioning Expenses 25.0% $2,011 $503 $2,513 $0 $0 $0 $2,011 $503 $2,513 9300 Capital Spares 15.0% $7,101 $1,065 $8,166 $0 $0 $0 $7,101 $1,065 $8,166 9400 Stores & Inventory 15.0% $1,420 $213 $1,633 $0 $0 $0 $1,420 $213 $1,633 9500 PPD Capitalized Operating 0.0% $4,584 $0 $4,584 $0 $0 $0 $4,584 $0 $4,584 9600 Escalation & Foreign Currency Exchange 0.0% $0 $0 $0 $0 $0 $0 $0 $0 $0 Pre-Production Costs 12.3% $16,121 $1,982 $18,102 $0 $0 $0 $16,121 $1,982 $18,102 22.3.9 1000 Asset Sale Table 22-13 depicts a total capital value of US$140 million. Table 22-13: Estimated Asset Sale (US$000s) Area Description Cont. (%) Initial Capital (US$000s) Sustaining Capital (US$000s) Total Capital (US$000s) Estimate Contingency Total Estimate Contingency Total Estimate Contingency Total 10000 ASSET SALE 10100 Mine 0.0% $0 $0 $0 ($52,926) $0 ($52,926) ($52,926) $0 ($52,926) 10200 Process Plant 0.0% $0 $0 $0 ($18,352) $0 ($18,352) ($18,352) $0 ($18,352) 10300 Power Plant (Sold to 3rd Party) 0.0% $0 $0 $0 ($68,352) $0 ($68,352) ($68,352) $0 ($68,352) Asset Sale 0.0% $0 $0 $0 ($139,631) $0 ($139,631) ($139,631) $0 ($139,631)

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 318 22.4 Operating Costs Estimated LoM operating costs are summarized in Table 22-14. The operating costs will average US$15.18/t-milled over the LoM. Table 22-14: Estimated LoM Operating Costs (US$) Description US$/t-milled US$/t-moved OPEN PIT MINE Mine General Service 0.10 0.03 Mine Maintenance 0.11 0.03 Engineering 0.05 0.01 Geology 0.03 0.01 Drilling 0.77 0.23 Blasting 1.17 0.35 Loading 0.60 0.18 Hauling 2.74 0.83 Mine Support 0.43 0.13 Mine Dewatering 0.01 0.004 Open Pit Mine 6.02 1.82 CIP PROCESS PLANT Labor 0.79 - 3100-Crush/Screen/Stockpile 0.18 - 3200-Reclaim & HPGR 0.44 - 3300-Classification & Grinding 3.14 - 3400-Pre-Leach,Thick/Aeration/CIP 0.13 - 3500-Desorption, Gold Room 0.02 - 3600-Detox & Tailings Pumping 0.06 - 3700-Reagents 2.98 - 3800-Plant Services 0.04 - Mining, Infrastructure & Misc 0.06 - General Consumables 0.01 - Plant Mobile Equipment 0.01 - Plant Gas Consumption 0.03 - CIP Process Plant 7.88 - Project Services $0.16 - G&A $1.11 - Operating Costs $15.18 -

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 319 22.4.1 Open Pit Mining Mining costs (including open pit mining, rehandle, and heap leach pad, but excluding capitalized preproduction mining costs) are shown in Table 22-15. Costs will average US$1.82/t-mined (US$6.02/t- milled) over the LoM. Hauling is the highest cost item, US$0.83/t-mined (US$2.74/t-milled). Hauling costs include transport of select mine waste to the TSF for embankment construction. Note also that unit costs per tonne milled include 13.4 Mt of heap leach ore which is not mined. Table 22-15: Estimated Open Pit Operating Costs (US$) Description US$/t-mined US$/t-milled Total (US$000s) Mine General Service $0.03 $0.10 $21,208 Mine Maintenance $0.03 $0.11 $24,605 Engineering $0.01 $0.05 $10,410 Geology $0.01 $0.03 $7,181 Drilling $0.23 $0.77 $170,765 Blasting $0.35 $1.17 $259,224 Loading $0.18 $0.60 $133,424 Hauling $0.83 $2.74 $606,582 Mine Support $0.13 $0.43 $94,880 Subtotal $1.82 $6.01 $1,328,278 Mine Dewatering $0.004 $0.012 $2,698 Total Open Pit Mining $1.82 $6.02 $1,330,976

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 320 22.4.2 CIP Process Plant CIP process plant operating costs averaging US$7.88/t-milled are shown in Table 22-16. Table 22-16: Estimated CIP Process Plant Operating Costs (US$) Description US$/t-milled Total (US$000s) Labor $0.79 $174,985 3100 – Crush/Screen/Stockpile $0.18 $40,426 3200 – Reclaim & HPGR $0.44 $96,902 3300 – Classification & Grinding $3.14 $693,910 3400 – Pre-Leach, Thick/Aeration/CIP $0.13 $28,863 3500 – Desorption, Gold Room $0.02 $4,087 3600 – Detox & Tailings Pumping $0.06 $12,856 3700 – Reagents $2.98 $659,075 3800 – Plant Services $0.04 $8,463 Mining, Infrastructure, & Misc $0.06 $12,494 Generable Consumables $0.01 $2,327 Plant Mobile Equipment $0.01 $1,793 Plant Gas consumption $0.03 $6,339 Total CIP Process Plant $7.88 $1,742,519 22.4.3 Water Treatment Plant Water treatment plant operating costs averaging US$0.09/t-milled are shown in Table 22-17. Table 22-17: Estimated Water Treatment Plant Operating Costs (US$) Description US$/t-milled Total (US$000s) CHEMICALS Caustic $0.000 $0 Chlorine $0.000 $0 Citric Acid $0.000 $0 Ferric Chloride $0.015 $3,340 Ferrous Sulfate $0.000 $0 Lime $0.031 $6,919 Sodium Hydrosulfate $0.002 $342 Sulfuric Acid $0.005 $1,073

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 321 Description US$/t-milled Total (US$000s) POWER Electricity $0.010 $2,285 LABOR Operator $0.006 $1,302 Maintenance $0.016 $3,455 Total Water Treatment Plant $0.085 $18,715 22.4.4 Tailings Tailings will average US$0.07/t-milled over the LoM as shown in Table 22-18. Tailings operating costs include shaping and compaction of the mine waste in the tailings embankments that hauled as a mining cost. Pumping and power costs for tailings facility operation are included in the Process Plant costing. Table 22-18: Estimated Tailings Operating Costs (US$) Description US$/t-milled Total (US$000s) Labor $0.032 $7,137 Equipment $0.041 $9,155 Total Tailings $0.074 $16,291 22.4.5 General & Administrative G&A will average US$1.11/t-milled over the LoM as shown in Table 22-19. Table 22-19: Estimated G&A Operating Costs (US$) Description US$/t-milled Total (US$000s) Labor, G&A $0.456 $100,725 Expenses $0.142 $31,331 Transport & Accommodation $0.074 $16,450 Fleet Vehicles $0.015 $3,403 Corporate Overhead $0.427 $94,375 Total G&A $1.114 $246,285

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 322 22.4.6 JAAC Royalty JAAC Royalty costs averaging US$0.32/t-milled are shown in Table 22-20. Table 22-20: Estimated JAAC Royalty Costs (US$) US$/t-milled Total (US$000s) JAAC Royalty $0.324 $71,615 Total JAAC Royalty $0.324 $71,615 22.4.7 Refining Costs Refining costs averaging US$0.08/t-milled are shown in Table 22-21. Table 22-21: Estimated Refining Costs (US$) US$/t-milled Total (US$000s) Refining Fee $0.018 $3,979 Golden Retention $0.032 $7,161 Purchase Discount-Gold $0.012 $2,652 Assay Fee $0.003 $761 Environmental Fee $0.007 $1,456 Freight & Insurance $0.005 $1,066 Total Refinery Costs $0.077 $17,075 22.4.8 Operating Cost Inputs Inputs used to estimate operating costs are summarized in this section.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 323 22.4.8.1 Labor The labor breakdown shown in Table 22-22 represents the personnel contingent at steady state operations. Labor rates are fully burdened, are presented in Australian Dollars, and are based upon recent Australian labor rate surveys provided by Vista. Additionally, matrix showing salaries at levels by position is provided in Table 22-23. Table 22-22: Estimated Labor Rates & Costs (AUD) Salary AUD Salary On- Costs % AUD Number of Employees per Shift Shift Codes Total Employees Required Annual Labor Costs Total AUD/Annum Resident Manager $335,000 27.0% $90,450 1 DP 1 $425,450 Mining Manager $244,000 27.0% $65,880 1 DP 1 $309,880 Processing Manager $244,000 27.0% $65,880 1 DP 1 $309,880 Admin Manager* $203,000 27.0% $54,810 0 DP 0 $0 OHS Manager* $178,000 27.0% $48,060 0 DP 0 $0 NPI Manager $244,000 27.0% $65,880 1 DP 1 $309,880 Subtotal 4 4 $1,355,090 HR Director $183,000 27.0% $49,410 1 DP 1 $232,410 Recruiting Officer $107,000 27.0% $28,890 2 DP 2 $271,780 Administration Secretary $86,000 27.0% $23,220 1 DP 1 $109,220 Administrative Assistant $81,000 27.0% $21,870 1 SW 3 $308,610 Receptionist $66,000 27.0% $17,820 1 DP 1 $83,820 Indigenous Liaison Officer $96,000 27.0% $25,920 1 DP 1 $121,920 Security Officer $81,000 27.0% $21,870 2 SW 6 $617,220 Community Liaison Officer $96,000 27.0% $25,920 1 DP 1 $121,920 Head of Security $112,000 27.0% $30,240 1 DP 1 $142,240 External Affairs Director $178,000 27.0% $48,060 1 DP 1 $226,060 Support Services Director $178,000 27.0% $48,060 1 DP 1 $226,060 Subtotal 13 19 $2,461,260

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 324 Salary AUD Salary On- Costs % AUD Number of Employees per Shift Shift Codes Total Employees Required Annual Labor Costs Total AUD/Annum Financial Controller $183,000 27.0% $49,410 1 DP 1 $232,410 Senior Accountant $137,000 27.0% $36,990 1 DP 1 $173,990 Accountant $112,000 27.0% $30,240 1 DP 1 $142,240 Accounting Clerk $76,000 27.0% $20,520 1 DW 2 $193,040 Payroll Clerk $76,000 27.0% $20,520 1 DP 1 $96,520 Subtotal 5 6 $838,200 IT Supervisor $112,000 27.0% $30,240 1 DP 1 $142,240 IT Technician $91,000 27.0% $24,570 1 DP 1 $115,570 Database Administrator $91,000 27.0% $24,570 1 DP 1 $115,570 Subtotal 3 3 $373,380 Metallurgical Superintendent $178,000 27.0% $48,060 1 DP 1 $226,060 Chief Metallurgist $178,000 27.0% $48,060 1 DP 1 $226,060 Plant / Production Metallurgist $157,000 27.0% $42,390 2 DP 2 $398,780 Process Control Engineer $137,000 27.0% $36,990 1 DP 1 $173,990 Metallurgical Clerk $91,000 27.0% $24,570 1 SW 3 $346,710 Gold Room Supervisor $112,000 27.0% $30,240 1 DP 1 $142,240 Refiner $96,000 27.0% $25,920 1 DW 2 $243,840 Gold Room Technician $91,000 27.0% $24,570 1 SW 3 $346,710 Subtotal 9 14 $2,104,390 Production Superintendent $183,000 27.0% $49,410 1 DP 1 $232,410 General Foreman $152,000 27.0% $41,040 1 DP 1 $193,040 Shift Foreman $127,000 27.0% $34,290 1 SW 3 $483,870 Plant Lead Operator $112,000 27.0% $30,240 1 SW 3 $426,720 Shift Operator - Crushing $102,000 27.0% $27,540 1 SW 3 $388,620

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 325 Salary AUD Salary On- Costs % AUD Number of Employees per Shift Shift Codes Total Employees Required Annual Labor Costs Total AUD/Annum Shift Operator - HPGR $102,000 27.0% $27,540 1 SW 3 $388,620 Shift Operator - Mills $102,000 27.0% $27,540 1 SW 3 $388,620 Shift Operator - Leach $102,000 27.0% $27,540 1 SW 3 $388,620 Shift Operator - Elution $102,000 27.0% $27,540 1 SW 3 $388,620 Shift Operator - Detox / Tailings $102,000 27.0% $27,540 1 SW 3 $388,620 Shift Operator - Reagents $102,000 27.0% $27,540 2 SW 6 $777,240 Shift Operator - CCR $102,000 27.0% $27,540 1 SW 3 $388,620 Shift Operator - Tailings Dam $91,000 27.0% $24,570 2 SW 6 $693,420 Shift Operator - Day Gang $91,000 27.0% $24,570 4 SW 12 $1,386,840 Subtotal 19 53 $6,913,880 Maintenance Superintendent $178,000 27.0% $48,060 1 DP 1 $226,060 Maintenance General Foreman $152,000 27.0% $41,040 1 DP 1 $193,040 Maintenance Planner $157,000 27.0% $42,390 1 DP 1 $199,390 Mechanical Fitter $122,000 27.0% $32,940 3 SW 9 $1,394,460 Crane Operator $102,000 27.0% $27,540 1 DW 2 $259,080 Boilermaker / Welder $127,000 27.0% $34,290 2 DW 4 $645,160 Pipe Fitters $127,000 27.0% $34,290 1 DW 2 $322,580 Greasers $91,000 27.0% $24,570 1 SW 3 $346,710 Trades Assistants $86,000 27.0% $23,220 1 SW 3 $327,660 Electrical General Foreman $147,000 27.0% $39,690 1 DP 1 $186,690 HV Electrical Supervisor $122,000 27.0% $32,940 1 DW 2 $309,880 Electrician $122,000 27.0% $32,940 3 SW 9 $1,394,460 Instrument Technician $122,000 27.0% $32,940 1 SW 3 $464,820 Apprentices $61,000 27.0% $16,470 2 SW 6 $464,820

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 326 Salary AUD Salary On- Costs % AUD Number of Employees per Shift Shift Codes Total Employees Required Annual Labor Costs Total AUD/Annum Subtotal 20 47 $6,734,810 Laboratory Supervisor $127,000 27.0% $34,290 1 SW 3 $483,870 Chemist $122,000 27.0% $32,940 1 SW 3 $464,820 Lab Technician $102,000 27.0% $27,540 2 SW 6 $777,240 Sample Prep Technician $76,000 27.0% $20,520 3 SW 9 $868,680 Subtotal 7 21 $2,594,610 Engineering Superintendent $183,000 27.0% $49,410 1 DP 1 $232,410 Chief Mining Engineer $162,000 27.0% $43,740 1 DP 1 $205,740 Senior Mining Engineer $142,000 27.0% $38,340 0 DP 0 $0 Mining Engineer $132,000 27.0% $35,640 1 DW 2 $335,280 Senior Mine Planning Engineer $132,000 27.0% $35,640 1 DP 1 $167,640 Mine Clerk $102,000 27.0% $27,540 1 DP 1 $129,540 Subtotal 5 6 $1,070,610 Operations Superintendent $183,000 27.0% $49,410 1 DP 1 $232,410 Mine General Foreman $152,000 27.0% $41,040 1 DP 1 $193,040 Drill and Blast Foreman $127,000 27.0% $34,290 1 DW 2 $322,580 Drill and Blast Technician $91,000 27.0% $24,570 1 DW 2 $231,140 Blasting Assistant $86,000 27.0% $23,220 1 DW 2 $218,440 Loading Operator $117,000 27.0% $31,590 3 SW 9 $1,337,310 Haul Truck Operator $102,000 27.0% $27,540 16 SW 48 $6,217,920 Drill Operators $117,000 27.0% $31,590 8 SW 24 $3,566,160 Mechanics $122,000 27.0% $32,940 0 SW 0 $0 Welders $127,000 27.0% $34,290 0 SW 0 $0 Servicemen $81,000 27.0% $21,870 0 SW 0 $0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 327 Salary AUD Salary On- Costs % AUD Number of Employees per Shift Shift Codes Total Employees Required Annual Labor Costs Total AUD/Annum Aux Equipment Operators $107,000 27.0% $28,890 12 SW 36 $4,892,040 Mine Shift Foreman $127,000 27.0% $34,290 1 SW 3 $483,870 Subtotal 45 128 $17,694,910 Maintenance Superintendent $178,000 27.0% $48,060 1 DP 1 $226,060 Maintenance General Foreman $152,000 27.0% $41,040 1 DP 1 $193,040 Light Vehicle Mechanic $122,000 27.0% $32,940 2 DW 4 $619,760 Tireman $91,000 27.0% $24,570 1 DW 2 $231,140 Shop Laborer $86,000 27.0% $23,220 2 SW 6 $655,320 Service, Fuel & Lube $81,000 27.0% $21,870 3 SW 9 $925,830 Maintenance Planner $127,000 27.0% $34,290 1 DP 1 $161,290 Subtotal 11 24 $3,012,440 Chief Surveyor $152,000 27.0% $41,040 1 DP 1 $193,040 Mine Surveyor $117,000 27.0% $31,590 1 DW 2 $297,180 Surveying Helper $81,000 27.0% $21,870 1 DW 2 $205,740 Subtotal 3 5 $695,960 GEOLOGY Geology Superintendent $178,000 27.0% $48,060 1 DP 1 $226,060 Grade Control Geologist $147,000 27.0% $39,690 1 DW 2 $373,380 Exploration Geologist $112,000 27.0% $30,240 1 DP 1 $142,240 Resource Geologist $157,000 27.0% $42,390 1 DP 1 $199,390 Pit Geology Technician $91,000 27.0% $24,570 3 DP 3 $346,710 Geology Field Technician $81,000 27.0% $21,870 2 DP 2 $205,740 Subtotal 9 10 $1,493,520 Purchasing Director $152,000 27.0% $41,040 1 DP 1 $193,040

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 328 Salary AUD Salary On- Costs % AUD Number of Employees per Shift Shift Codes Total Employees Required Annual Labor Costs Total AUD/Annum Business Development Officer $96,000 27.0% $25,920 1 DP 1 $121,920 Logistics Officer $132,000 27.0% $35,640 1 DP 1 $167,640 Purchasing Officer $96,000 27.0% $25,920 1 DP 1 $121,920 Contracts Officer $112,000 27.0% $30,240 1 DP 1 $142,240 Store Person $86,000 27.0% $23,220 1 SW 3 $327,660 Subtotal 6 8 $1,074,420 OHS Superintendent $178,000 27.0% $48,060 1 DP 1 $226,060 Safety Officer $117,000 27.0% $31,590 1 SW 3 $445,770 Paramedic / Nurse $117,000 27.0% $31,590 1 SW 3 $445,770 Environmental Superintendent $152,000 27.0% $41,040 1 DP 1 $193,040 Environmental Officer - Monitoring $107,000 27.0% $28,890 1 DP 1 $135,890 Environmental Officer - Compliance $107,000 27.0% $28,890 1 DP 1 $135,890 Subtotal 6 10 $1,582,420 Training Coordinator $152,000 27.0% $41,040 1 DP 1 $193,040 Training Officer - Plant $122,000 27.0% $32,940 2 DW 4 $619,760 Training Officer - Mining $122,000 27.0% $32,940 2 DW 4 $619,760 Subtotal 5 9 $1,432,560 Camp Manager $96,000 27.0% $25,920 0 DP 0 $0 Camp Admin $71,000 27.0% $19,170 0 DW 0 $0 Cook Staff $86,000 27.0% $23,220 0 SW 0 $0 Cleaning Staff $86,000 27.0% $23,220 0 DW 0 $0 Camp Maintenance $102,000 27.0% $27,540 0 DP 0 $0 Bus Drivers $81,000 27.0% $21,870 4 SW 12 $1,234,440

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 329 Salary AUD Salary On- Costs % AUD Number of Employees per Shift Shift Codes Total Employees Required Annual Labor Costs Total AUD/Annum Subtotal 4 12 $1,234,440 Power Station Operator $91,000 27.0% $24,570 1 SW 3 $346,710 Electrician $122,000 27.0% $32,940 1 SW 3 $464,820 Mechanic $122,000 27.0% $32,940 1 SW 3 $464,820 Subtotal 3 9 $1,276,350 Power & Water Superintendent $152,000 27.0% $41,040 1 DP 1 $193,040 Water Plant Operator $91,000 27.0% $24,570 1 SW 3 $346,710 Water Plant Mechanic $122,000 27.0% $32,940 1 SW 3 $464,820 Subtotal 3 7 $1,004,570 Dozer Operator $107,000 27.0% $28,890 2 DW 4 $543,560 Loader Operator $107,000 27.0% $28,890 0.8 DP 0.8 $108,712 Haul Truck Operator $102,000 27.0% $27,540 0.3 DP 0.3 $38,862 Subtotal 3 5 $691,134 Dozer Operator $107,000 27.0% $28,890 1.3 DP 1.3 $176,657 Loader Operator $107,000 27.0% $28,890 0.17 DP 0.17 $23,101 Haul Truck Operator $102,000 27.0% $27,540 0.51 DP 0.51 $66,065 Crane Operator $112,000 27.0% $30,240 0.14 DP 0.14 $19,914 Subtotal 2 2 $285,737 Project Superintendent $203,000 27.0% $54,810 1 DP 1 $257,810 Project Engineer $167,000 27.0% $45,090 1 DW 2 $424,180 Civil Engineer $132,000 27.0% $35,640 0 DW 0 $0 Geotechnical Engineer $152,000 27.0% $41,040 0 DW 0 $0 CAD Draftsman $89,000 27.0% $24,030 0 DW 0 $0 Piping Engineer $107,000 27.0% $28,890 0 DW 0 $0

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 330 Salary AUD Salary On- Costs % AUD Number of Employees per Shift Shift Codes Total Employees Required Annual Labor Costs Total AUD/Annum Document Controller $76,000 27.0% $20,520 0 DW 0 $0 Construction Supervisor $132,000 27.0% $35,640 0 DW 0 $0 Subtotal 2 3 $681,990 TOTAL ONSITE PERSONNEL 405 $56,606,681 *Vista has identified these as possible needs, but they are not currently in the total manpower calculations.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 331 Table 22-23: Position & Salary Matrix (AUD) Salary (AUD) Mine Technical Mine Operations Mine Maintenance Plant Technical Plant Operations Plant Maintenance NPI Administration $335,000 Resident Manager $244,000 Mining Manager Processing Manager NPI Manager $203,000 Admin Manager* $203,000 Projects Supt. $183,000 Engineering Supt. Operations Supt. Production Supt Financial Controller HR Director $178,000 Geology Supt. Maintenance Supt Metallurgy Supt Maintenance Supt. OHS Supt.* External Affairs Director Support Services Director $167,000 Project Engineer $162,000 Chief Mining Engineer $157,000 Resource Geologist Chief Metallurgist Maintenance Planner $152,000 Chief Surveyor Mine General Foreman Metallurgist General Foreman Mechanical General Foreman Power & Water Supt Environmental Supt Purchasing Director

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 332 Salary (AUD) Mine Technical Mine Operations Mine Maintenance Plant Technical Plant Operations Plant Maintenance NPI Administration Training Coordinator $147,000 Ore Control Geologist $152,000 Maintenance General Foreman Electrical General Foreman $137,000 Sr. Accountant $132,000 Sr. Mine Planning Engineer Logistics Officer Mining Engineer $127,000 Mine Shift Foreman Maintenance Planner Laboratory Supervisor Plant Shift Foreman Welder/Pipefitt er $127,000 Light Vehicle Mechanic Chemist High Voltage Electrician Power Station Electrician Training Officer - Mine Equip Drill & Blast Foreman Electrician Power Station Mechanic Training Officer - Fixed Plant Instrumentation Tech Water Plant Mechanic Mechanical Fitter $117,000 Mine Surveyor Drill Operator Safety Officer Shovel Operator Paramedics $112,000 Exploration Geologist Plant Lead Operator Contracts Officer Accountant Gold Room Supervisor IT Supervisor

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 333 Salary (AUD) Mine Technical Mine Operations Mine Maintenance Plant Technical Plant Operations Plant Maintenance NPI Administration $107,000 Aux Equipment Operator Env Officer - Monitoring Env. Officer - Compliance $102,000 Mine Clerk Haul Truck Operator Crushing/ Sorting Operator Crane Operator Recruiting Officer Grinding/Leach Operator Head of Security $96,000 Refiner Purchasing Officer Business Dev. Officer Community Liaison Officer Indigenous Liaison Officer $91,000 Pit Geology Technician Drill & Blast Technician Tireman Metallurgy Clerk Grinding/Leach Technician Greaser Power Station Operator IT Technician Lab Technician Tailings Technician Water Plant Operator Database Administrator Gold Room Technician Plant Day Gang $86,000 Blasting Assistant Maintenance Shop Labor Trades Assistant Store Person Administrative Secretary

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 334 Salary (AUD) Mine Technical Mine Operations Mine Maintenance Plant Technical Plant Operations Plant Maintenance NPI Administration $81,000 Surveyor Helper Fuel & Lube Technician Administrative Assistant Geology Field Technician Security Officer Bus Driver $76,000 Sample Prep Technician Accounting Clerk Payroll Clerk $66,000 Receptionist *Vista has identified these as possible needs, but they are not currently in the total manpower calculations.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 335 22.4.8.2 Reagents Reagent consumption rates and costs are shown in Table 22-24. Consumption rates are based upon metallurgical testwork and prices are based on vendor quotes, including a delivery to site. Unit costs of reagents are provided in AUD. Table 22-24: Process Reagents (AUD) Reagent Consumable Rate Unit Unit Cost (AUD) Unit Quick Lime 2,800 g/t leach feed $370 per tonne Sodium Cyanide 876 g/t leach feed $2,887 per tonne Sodium Hydroxide 40 g/t ore $1,123 per tonne Flocculant 40 g/t leach feed $3,239 per tonne Sodium Metabisulphite (SMBS) 732 g/t leach feed $602 per tonne Hydrochloric Acid 81 g/t ore $723 per tonne Lead Nitrate 100 g/t ore $3,866 per tonne Activated Carbon 20 g/t ore $2,909 per tonne Borax 150 kg/t conc. $3,286 per tonne Silica 150 kg/t conc. $1,866 per tonne Soda Ash 100 kg/t conc. $1,966 per tonne Potassium Nitrate 30 kg/t conc. $4,066 per tonne 22.4.8.3 Consumables Consumable consumption rates are based upon benchmark data and vendor information given the ores processed at the site. Costs for consumables are based upon vendor quotes including delivery to site. These costs are shown in Table 22-25. Unit costs of consumables are provided in AUD. Table 22-25: Process Consumables (AUD) Consumables Consumable Rate Unit Unit Cost (AUD) Unit CRUSHING Primary Crusher mantle 131 days per set $277,242 per mantle Primary Crusher concaves 272 days per set $265,861 per set Secondary Crushers Main frame Liners 481 days per unit $44,115 per unit Secondary Crushers Bowl Liners 61 days per unit $37,193 per unit Secondary Crusher Mantle 61 days per unit $29,997 per unit MILLING Mill Balls 65mm 0.06 kg / kWh $1,373 per tonne Mill Liners 1.0 sets per annum / mill $1,005,714 per set

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 336 Consumables Consumable Rate Unit Unit Cost (AUD) Unit Secondary Grinding Media 0.35 kg / kWh $6.23 per kg HPGR Cheek plates 7,838 h/set $242,000 per set Tires 13,000 h/set $1,544,871 per set LIME SLAKER Mill Balls 50 mm Lime Slaking Mill 0.5 kg/t lime $1,380 per tonne 22.4.8.4 Diesel Consumption The primary consumer of diesel is mining, which totals 494 million liters of diesel. The total project consumption of diesel is 503 million liters. 22.4.8.5 Plant Power Consumption The primary consumer of power is the process facility, which totals 8,086,773 MWh power. The total project consumption of power is 8,137,558 MWh. 22.5 Economic Results Project cost estimates and economics are prepared on an annual basis. Based upon design criteria presented in this report, the level of accuracy of the estimate is considered ±25%. Economic results are summarized in Table 22-26. The analysis suggests the following conclusions, assuming a 100% equity project at a gold price of US$1,350: „ Mine Life: 13 years; „ Pre-Tax NPV5%: US$1,440 million, IRR: 30.4%; „ After-tax NPV5%: US$823 million, IRR: 23.4%; „ Payback (After-tax): 2.9 years; „ NT Royalty Paid: US$473 million; „ Australian Income Taxes Paid: US$553 million; and „ Cash costs (including JAAC Royalty): US$645.14/oz-Au. Table 22-26: Technical-Economic Results (US$000s) Cash Flow Summary LoM (US$000s) Unit Cost US$/t-milled US$/oz-Au Gold Sales Gold Produced (koz) 5,305 - - Gold Price (US$/oz) 1,350 - - Gold Sales 7,161,494 32.40 1,300 Refining & Royalties Refinery Costs (17,075) (0.077) (3.22)

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 337 Cash Flow Summary LoM (US$000s) Unit Cost US$/t-milled US$/oz-Au JAAC Royalty (71,615) (0.324) (13.50) Gross Income from Mining 7,072,805 31.998 1,333 Operating Costs Open Pit Mine (1,330,976) (6.02) (251) CIP Process Plant (1,742,519) (7.88) (328) Project Services (35,007) (0.16) (6.60) G&A (246,285) (1.11) (46.43) Operating Costs (3,354,787) (15.18) (632.40) Power Sales Credit 21,156 0.096 3.99 Cash Cost of Goods Sold (COGS) (3,422,321) (15.48) (645.14) Operating Margin 3,739,174 16.92 704.86 Capital Costs Mining 565,982 Process Plant 437,016 Project Services 199,787 Project Infrastructure 29,623 Permanent Accommodation 66 Site Establishment & Early Works 19,532 Management, Engineering, EPCM Services 91,779 Pre-Production Costs 18,102 Asset Sale (139,631) Capital Costs 1,222,257 Pre-Tax Cash Flow 2,511,917 NPV5% 1,440,469 IRR (%) 30.4% After-tax Cash Flow 1,439,863 NPV5% 823,125 IRR (%) 23.4% After-tax Payback (years) 2.9 Cash costs for the Project are presented in Table 22-27. Table 22-27: All-In Sustaining Costs (US$/oz) Period Cash Cost Sustaining AISC First 60 Mo. Of Prod. USD 574.71 USD 112.93 USD 687.64 LoM USD 645.14 USD 101.07 USD 746.21

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 338 Cash costs would typically include Non-cash remuneration for site personnel and AISC would include corporate G&A (including share-based remuneration). For cash costs, non-cash remuneration could be defined to include share-based comp for site personnel. The model’s $780k per year has not been included. This expense has no impact on cashflows that generate NPV and IRR and is only about $1.50/oz (after tax) LOM. This is not a material deviation from the World Gold Counsel’s (WGCs) definition. As to AISC, the model taxes an accrual-based tax deduction of $1.2 million per year but does not deduct such expense from cashflows, so there in no impact on NPV or IRR except to the extent this expense reduces NT royalty and Commonwealth income taxes. This would equate to about $2/oz, which is not material.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 339 Table 22-28: Annual Cash Flow

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 340 22.5.1 Taxes, Royalties Taxes, royalties, and working capital were incorporated to the economic model by Vista. 22.5.1.1 Royalties NORTHERN TERRITORY ROYALTY Under the NT Mineral Royalty Act (November 2014) (the “MRA”), royalties are based on the net value of production from a mine when annual gross production revenue of a production unit exceeds AUD500,000, irrespective of the nature of the land holding. The royalty payable under the MRA is the greater of: (a) 20 per cent of the net value, less $10 000, or (b) the percentage of the gross production revenue applying to the royalty year as follows: (i) 1% for the royalty payer’s first royalty year that begins on or after July 1, 2019; (ii) 2% for the royalty year that follows the royalty year mentioned in subparagraph (i); or (iii) 2.5% for each royalty year that follows the royalty year mentioned in subparagraph (ii). The Northern Territory Government imposes a net value-based royalty, much like an income tax, on mine production (the “NT Royalty”). The MRA codifies the calculation of the Northern Territory Royalty; however, determination and collection of the NT Royalties is not fully a matter of public record. Some mines appear to be subject to legacy customized arrangements with the NT Government, which seem to offer relief with respect to the amount and/or timing of royalty payments; and other mines appear to pay no royalty. Such agreements are confidential and each is subject to a formal application process. The NT Royalty calculated for the Project cashflows is based on the MRA rules, together with reasonable assumptions about the nature of relief that appears to be available to new mines. Net value of production for the purposes of calculating the royalty is based the formula: NV = GR – (OC + CRD + EEE + AD) where: NV is the net value from a production unit in a royalty year; GR is the gross realization from the production unit in the royalty year; OC is the operating costs of the production unit for the royalty year; CRD is the capital recognition deduction; EEE is the eligible exploration expenditure, if any; and AD is any additional deduction.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 341 22.5.1.2 Other Royalties For rent of the surface rights from the current mining licenses, including the mining license on which the Batman deposit is located, the JAAC is entitled to an annual amount equal to 1% of the gross value of production with a minimum annual payment of AUD50,000. There is also a royalty of 5% based on the gross value of any gold or other metals that may be commercially extracted from certain mineral concessions (the Denehurst Royalty). The Denehurst Royalty would not apply to presently identified mineralized zone at Mt Todd. 22.5.1.3 Taxes AUSTRALIAN COMMONWEALTH INCOME TAX The applicable corporate income tax rate in Australia is 30%. Taxable income is based on assessable income less allowable deductions. Assessable income generally includes gross income from the sale of goods, the provision of services, dividends, interest, royalties and rent. Assessable income may also include capital gains after offsetting capital losses. Normal business expenses are deductible. Tax losses may be utilized and carried forward indefinitely to offset against future assessable income provided a “continuity of ownership” (more than 50% of voting, dividend and capital rights) or a “same business” test is satisfied. Thin capitalization provisions can limit the deductibility of interest and other “debt deductions” in certain cases. In general, a deduction will be partly disallowed if the company’s debt exceeds three times its equity. Transfer pricing rules apply to international transactions/dealings between separate legal entities. Covered cross-border transactions include those involving tangible or intangible property, the provision of services and financing. There are several generally accepted transfer pricing methods available in Australia. Consolidation allows wholly owned corporate groups to operate as a single entity for income tax purposes. Australia operates a full imputation system for the avoidance of double taxation of dividends. Under this system, the payment of company tax is imputed to shareholders so that shareholders are relieved of their tax liability to the extent profits have been taxed at the corporate level. Dividends paid out of profits on which corporate tax has been paid are said to be “franked” and generally entitle shareholders to an offset for the corporate tax paid.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 342 22.5.2 Sensitivity Project sensitivities are summarized in Table 22-29, Table 22-30, and Table 22-31; sensitivities are shown graphically in Figure 22-1. As seen, the Project is most sensitive to gold production and gold price. Sensitivity on operating and capital cost is closely matched, with the Project being only slightly more sensitive to operating costs. Table 22-29: Project Sensitivity Parameter 85% 90% 95% Base 105% 110% 115% Gold Price 419,574 554,147 683,823 823,125 962,354 1,096,323 1,230,036 Opex 1,030,506 963,805 896,328 823,125 748,383 679,009 609,361 Capex 954,399 910,641 866,883 823,125 779,904 736,755 695,643 Source: JDS Energy & Mining, September 9, 2019 Figure 22-1: Project Sensitivity

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 343 Table 22-30: Sensitivities to Gold Price versus NPV Discount Rate Discount Rate (%) Gold Price (US$/oz-Au) 800 1,000 1,200 1,300 1,350 1,400 1,500 1,700 1,900 5 (551) 61 525 718 823 928 1,126 1,533 1,932 8 (557) (58) 326 485 571 656 818 1,149 1,474 10 (555) (115) 225 366 442 516 659 950 1,237 Table 22-31: Sensitivities to Gold Price versus Foreign Exchange Rate (US$:AUD) Foreign Exchange Gold Price (US$/oz-Au) 800 1,000 1,200 1,300 1,350 1,400 1,500 1,700 1,900 (US$/AUD) IRR (%) NPV(5) IRR (%) NPV(5) IRR (%) NPV(5) IRR (%) NPV(5) IRR (%) NPV(5) IRR (%) NPV(5) IRR (%) NPV(5) IRR (%) NPV(5) IRR (%) NPV(5) 0.60 (1.3) (265) 12.1 290 21.6 687 26.3 895 28.4 994 30.5 1,094 34.7 1,296 43.4 1,700 50.6 2,099 0.65 (4.7) (410) 9.8 206 19.2 604 23.7 807 25.8 911 27.9 1,011 32.0 1,209 40.3 1,617 47.4 2,015 0.70 (7.9) (552) 6.4 61 16.9 525 21.2 718 23.4 823 25.4 928 29.4 1,126 37.4 1,533 44.4 1,932 0.75 (11.0) (693) 4.1 (42) 14.7 440 18.9 636 20.9 734 23.1 839 27.0 1,043 34.7 1,445 41.6 1,848 0.80 (13.9) (835) 1.9 (150) 12.6 355 16.8 557 18.8 652 20.7 750 24.7 954 32.2 1,362 39.0 1,765

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 344 23.0 ADJACENT PROPERTIES There are no adjacent properties that are considered relevant to this Technical Report.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 345 24.0 OTHER RELEVANT DATA AND INFORMATION 24.1 Process Plant Geotechnical Bulk earthworks for the process plant are designed to minimize the import of fill material and excavation of rock. Where fill material is required to be imported, either material from the existing RoM Pad ramp; from the existing stockpile located adjacent to the Tollis and Golf Pits; or from the WRD will be utilized. The civil basis of design took into consideration the following geotechnical information: „ Geotechnical Desktop Study Mt Todd Process Plant DFS undertaken by Coffey Geotechnics in December 2012. The study reviewed previous Soil and Rock Engineering (SRE) geotechnical data from December 1992 and April 1993 for the original Mt Todd development. The study also reviewed SRE earthworks monitoring data for construction of the original Mt Todd development. Geotechnical test pit data was also reviewed (Tetra Tech, 2013). The study focused on foundations for heavy vibrating loads including the crusher and mill as well as screening structures and ancillary plant buildings. A review of potential borrow material in close proximity to the proposed plant site suitable for structural fill and pavement construction was also included. „ Foundation Recommendations report produced by Tetra Tech in April 2012. The geotechnical test pit investigation was conducted in October 2011 at the then proposed location of the process plant. A summary of the test pit investigation and preliminary recommendations for foundation design at the site were provided. „ Technical Memorandum regarding “Results of Test Pit Excavation Program and Borrow Source Investigation, Mt Todd Project, Vista Gold Corporation, Northern Territory, Australia” from Tetra Tech dated 20 December 2012. A summary of the test pit results and potential borrow sources were provided. „ Foundation Recommendations report produced by Tetra Tech in February 2013. The report reviewed previous SRE geotechnical data from December 1992 and April 1993 for the original Mt Todd development. The report also reviewed previous Foundation Recommendations report produced by Tetra Tech in April 2012 and the previous geotechnical test pit investigation conducted in December 2012 at the proposed location of the process plant. A summary of the test pit investigation and recommendations for foundation design at the site were provided. Further geotechnical investigation is recommended during the next design phase of the project to obtain geotechnical data in the final location of foundations for heavy vibrating loads including the crusher and mill as well as screening structures and ancillary plant buildings. The investigation also is required to confirm fill material and rock excavation requirements, as well as locating borrow sources that are closer to the planned operation that may reduce these costs.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 346 24.2 Water Management This section describes the overall Project water management and infrastructure considerations. 24.2.1 Site-wide Water Balance A site-wide water balance (SWWB) was developed within the GoldSim® software platform (Version 11.1) to simulate 13 years of mine production (12 active mining years and 1 additional year processing stockpiles) at the Vista Project Site. The SWWB was developed to simulate site conditions in order to: „ Validate adequacy of water treatment plant capacity; „ Validate adequacy of equalization pond sizing; and „ Quantify make up water requirements from the RWD for process make up water, dust control, and potable/elution needs. 24.2.1.1 Site-wide Water Balance Model WATER BALANCE MODELING The SWWB model was constructed using deterministic (known with certainty) inputs, such as pond stage- storage relationships, as well as stochastic (known, but with some uncertainty) inputs, such as rainfall. Water storage within retention ponds (RPs) was modeled using the basic formula: Change in Storage = Inputs – Outputs Information provided to the model and the rules by which the site features interacted are summarized below. MODEL ELEMENTS The site features (pits, facilities and associated RPs) represented within the model are: „ Waste Rock Dump (WRD, RP1); „ Low Grade Ore Stockpile (LGOS) „ Low Grade Ore Stockpile Retention Pond (LGRP); „ Batman Pit (BP, RP3); „ Process Plant Retention Pond (PRP); „ Heap Leach Pad (HLP); „ Raw Water Dam (RWD); „ Process Water Pond (PWP); „ Water Treatment Plant (WTP); „ Process Plant (PP); „ Dust Control; „ Tailings Storage Facility 1 (TSF 1, RP7); and „ Tailings Storage Facility 2 (TSF 2).

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 347 GENERAL ASSUMPTIONS Interaction between site features was modeled based on the following set of guidelines: „ RP1, LGRP, RP3, PRP and the HLP report to the PWP which feeds the WTP; „ The PWP receives water only if it is not at risk for overtopping. Given this logic, overtopping events are allowed to occur at the RPs; „ Inputs to ponds included precipitation, catchment runoff (where applicable), seepage (where applicable), and groundwater inflow (where applicable); „ Outputs from ponds included evaporative loss, pumping and overtopping events (uncontrolled releases); „ All RPs report to the PWP which feeds directly to WTP. The PWP was sized to contain six days of WTP capacity (72,000m3); „ A process plant bleed stream of 229 m3/hr is sent to the PWP to maintain chemistry of the process circuit; „ Discharges to the Edith River were not allowed from any of the RPs. „ WTP effluent was allowed to discharge to the Edith River only during the wet season; „ The HLP was run through process at the end of the Life of Mine (LoM); „ WRD water that reported to RP1 was not allowed to be used for dust control; „ Seepage losses from the ponds are not modeled and are assumed to be zero; and „ RWD is modeled as an infinite source for site water needs due to lack of information about its catchment area and stage-storage relationship. INITIAL CONDITIONS „ RP1, LGRP, RP3, PRP and the PWP were assigned water surface elevations based on outputs from the pre-production model, which concluded at the initiation of production with initial conditions based on real site water surface elevation observations from December 2016. „ The dust suppression tank was assumed to be full at the initiation of production. FLOW RATES „ Process makeup water requirements throughout the LoM were 1,764 m3/hr. This value accounts for recycle from the thickener overflow within the Process circuit. „ TSF decant flows were 1,460 m3/hr. „ RWD process makeup water flows were 304 m3/hr. „ Dust suppression requirements varied between 220 and 1,153 m3/day. „ WTP capacity is 500 m3/hr.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 348 CLIMATOLOGICAL INPUTS The Vista Project SWWB model was designed to reflect weather conditions as accurately as possible, given the arid tropical climate (i.e., wet, monsoon conditions with intense, short-lived events and extended hot, dry periods). Features within the climatological section of the model included: „ Stochastic precipitation inputs, such that a range of likely scenarios may be determined, thus allowing the user an understanding of dry (5-percentile), typical (mean) and wet (95-percentile) climatological effects on the site. Precipitation was entered as a statistical probability, rather than assuming rainfall on a given day and assigning a rainfall depth. The mean monthly total precipitation values (total mm per month) provided to the model are shown in Table 24-1. Table 24-1: Mean Monthly Precipitation Month Precipitation (mm) January 292 February 259 March 193 April 38 May 6 June 2 July 1 August 1 September 7 October 35 November 111 December 239 „ Synthetic data were used to extend the precipitation period of record and identify extreme rainfall events. Project Site precipitation data were collected from 1993 to present. A correlation of the site data to a nearby Katherine gage allowed the rainfall time series to be extended to that of the Katherine gage, 138 years, thus allowing determination of extreme rainfall events that may not otherwise present within a data set spanning less than 25 years. „ Linking incidental rainfall and runoff within the Edith River using the Australian Water Balance Method. Catchment parameters within the model were adjusted to ensure optimal agreement between modeled runoff and observed Edith River flows. Measured precipitation, evaporation and Edith River flow data were used to calibrate this portion of the model. „ The model used stochastic evaporation, based on a monthly time step and calculated by the Blaney-Criddle method. The Blaney-Criddle approach recommends against use of a time step smaller than one month.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 349 MODEL RUN A time step of one day was selected for the site-wide water balance model. Use of stochastic inputs allowed a “Monte Carlo” analysis to be run wherein the 13-year LoM was simulated across 1,000 realizations (or equally likely weather scenarios), each incorporating the uncertainty associated with meteorological conditions and collectively providing an envelope of expected outcomes at the site. All RPs were subjected to the stochastic weather events as described in the previous section and reported to the WTP. 24.2.1.2 Results Under the modeled conditions described previously the SWWB model results indicate that: „ The Batman Pit will see water storage during the wet season and later in the life of mine. This is a result of incorporating groundwater inflows into this iteration of the SWWB model. Further investigation of potential groundwater inflows will be required to validate these groundwater inflows. Optimization of process makeup water usage and onsite reuse of stormwater could reduce the amount of water reporting to the PWP, thus, allowing for faster dewatering of the Batman Pit. „ The greatest amount of make-up water required from the RWD is quantified as 11,955 m3/day. RWD requirements were found to be the most dependent upon TSF decant volumes. „ RP1, LGRP, PRP, and the HLP show less than a 1% percent probability of having an overtopping over the LoM1. LGRP storage may be optimized. 24.2.2 Wet Infrastructure Section 18.2 – Facility 4000 Project Services discusses water supply inclusive of the water treatment plant (WTP), raw water, and potable water supply. Additional information regarding regulations, design criteria and receiving water is provided herein. 24.2.2.1 Water Treatment Plant Flow to the Process Water Pond, a combination of decant return, runoff pond water, and pit dewatering discharge, is stored and pumped to the Water Treatment Plant (WTP). The maximum design capacity of the WTP is 500 m³/hr. The WTP has been designed by Tetra Tech and its discharge will be returned to the Edith River for disposal, pursuant to the conditions defined by Water Discharge Licence 178-06 (WDL). During the dry season, when discharge is not allowed by the WDL, the WTP effluent will be used in the process plant for process water and around the site as dust suppression. 24.2.2.2 Water Quality Standards for Waste Water Discharge Discharges from the site are currently regulated by Waste Discharge Licence 178-06 (WDL), issued by the Northern Territory Government on November 26, 2018. The WDL is formal approval under section 74 of the Northern Territory Water Act that authorizes and regulates the release of potential contaminants to water in the Northern Territory to ensure environmental protection objectives are met. The Mt Todd Environmental Impact Statement (GHD, 2013) indicates that after the WTP is operational, the WDL will be revised to implement 95% species protection trigger values, as defined in the Australian and New Zealand Environment 1 A typical value is given. Separate model runs provide a range of overtopping events, due to the stochastic nature of the model.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 350 and Conservation Council (ANZECC) Guidelines for Fresh and Marine Water Quality (ANZECC 2000 Guidelines). This change will be reflected in a revision to WDL 178. The purpose of the 95% species protection trigger value (TV) is to protect water quality in the Edith River downstream of the discharge from the WTP. The WTP will discharge effluent into Batman Creek, a tributary to the Edith. Concentrations of contaminants measure in the Edith River shall not exceed the TV during discharge events. For the contaminants of concern at the Project, the TVs are presented in Table 24-2. Table 24-2: Site-specific Trigger Values, Edith River Downstream of WTP Discharge Analyte Unit Trigger Value Source pH s.u. 6-8 ANZECC 2000 Guidelines, Table 3.3.4, Lowland River value Dissolved Oxygen % Saturation 85-120 ANZECC 2000 Guidelines, Table 3.3.4, Lowland River Value Conductivity μS/cm 20-250 ANZECC 2000 Guidelines, Table 3.3.5, Upland and Lowland River Value Magnesium mg/L 2.5 Van Dam, et al. 2010 Environ Toxicol Chem 29(2):410-421 Sulphate mg/L 129 Elphick et al. 2011 Environ Toxicol Chem 30(1):247-253 Aluminum μg/L 55 ANZECC 2000 Guidelines Table 3.4.1 Cadmium μg/L 0.2 ANZECC 2000 Guidelines Table 3.4.1 Cobalt μg/L 90 ANZECC 2000 Guidelines p. 8.3-118 Chromium (III) μg/L 3.3 ANZECC 2000 Guidelines p. 8.3-116 Chromium (VI) μg/L 1.0 ANZECC 2000 Guidelines Table 3.4.1 Copper μg/L 1.4 ANZECC 2000 Guidelines Table 3.4.1 Manganese μg/L 1900 ANZECC 2000 Guidelines Table 3.4.1 Nickel μg/L 11 ANZECC 2000 Guidelines Table 3.4.1 Lead μg/L 3.4 ANZECC 2000 Guidelines Table 3.4.1 Iron μg/L 300 ANZECC 2000 Guidelines p. 8.3-123 Mercury μg/L 0.6 ANZECC 2000 Guidelines Table 3.4.1 Zinc μg/L 8.0 ANZECC 2000 Guidelines Table 3.4.1 The TVs for magnesium and sulphate have been held over from previous work, and are not referenced in the ANZECC 2000 Guidelines. To determine the allowable level of water quality constituents in the discharge of the WTP, a mass balance was performed on the Edith River system. Upstream water quality values at sampling location SW2 on the Edith River, flow in the river at sampling location SW4 downstream of the WTP discharge, and the maximum WTP effluent flow were used to calculate effluent limits at the WTP that would maintain the site-specific trigger value at site SW4. The equation used to determine the effluent limits is: ܳௐ்௉ܥௐ்௉ + ܳௌௐଶܥௌௐଶ = ܳௌௐସܥௌௐସ

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 351 Where: Q WTP is the WTP maximum flow rate C WTP is the allowable concentration of a given analyte in the WTP effluent Q SW2 is the flow in the Edith River upstream of the WTP C SW2 is the background concentration of a given analyte in the Edith River upstream of the WTP Q SW4 is the flow in the Edith River downstream of the WTP C SW4 is the background concentration of a given analyte in the Edith River downstream of the WTP Field data was used to determine values for QSW4, and CSW2. Table 24-3 presents Edith River flows at field monitoring location SW4 for the wet season, when the water treatment plant will discharge to the environment. Table 24-3: Edith River Flow at SW4 (m3/h), February 2013 – September 2017 Month Mean Median 5th Percentile 95th Percentile Maximum Day Minimum Day January 91,374 46,807 8,990 307,729 740,452 4,942 February 95,600 43,478 5,787 319,207 865,929 0 March 43,820 20,662 5,575 154,660 523,141 3,064 April 15,686 7,286 851 33,399 419,285 480 May 3,121 1,892 0 9,912 12,655 0 June 1,595 300 0 6,635 7,346 0 July 1,024 0 0 4,485 4,915 0 August 3,990 0 0 9,677 110,348 0 September 996 0 0 5,489 19,784 0 October 6,575 0 0 73,395 101,972 0 November 4,199 0 0 35,611 83,242 0 December 32,600 11,835 3,831 114,225 297,810 3,543 The wet season reliably extends between December and March, and the flow in the Edith River will provide a significant amount of dilution for the WTP effluent. Discharges to the environment will only occur between December and March.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 352 Table 24-4 provides a summary of field data showing background water quality concentrations of constituents of concern at sampling site SW2, upstream of the WTP on the Edith River. For this assessment, it was assumed that non-detectable sampling events were equal to the minimum detection limit of the analytical method. Table 24-4: Water Quality Data at Sampling Site SW2, Edith River Upstream of WTP Discharge, January 2015 – April 2017 Analyte Unit No. of Samples Minimum Value Maximum Value 5th Percentile Value 95th Percentile Value Average Value Magnesium mg/L 81 0.5 1.0 0.5 1.0 0.7 Sulphate mg/L 139 1 19 1 1 1.16 Aluminum μg/L 139 30 940 69 622 247 Cadmium μg/L 139 0.1 0.1 0.1 0.1 0.1 Cobalt μg/L 75 0.5 1.4 0.5 1.1 0.70 Chromium μg/L 88 1 2 1 1 1.01 Copper μg/L 134 1 20 1 2 1.34 Manganese μg/L 88 7 51 8 24.3 14.4 Nickel μg/L 88 1 2 1 1 1.03 Lead μg/L 88 1 1 1 1 1 Iron μg/L 139 430 1600 450 1100 751 Mercury μg/L 88 0.05 0.05 0.05 0.05 0.05 Zinc μg/L 88 1 16 1 8.65 3.56 Using the TVs presented in Table 24-2, the background flow rate presented in Table 24-3, the background water quality in Table 24-4, and a WTP discharge flow rate of 500 m3/h, the mass balance was solved for the allowable discharge concentrations at the WTP. Table 24-5 summarizes the allowable effluent concentrations and the WTP effluent goals, which are set at 80% of the allowable concentration to allow for a factor of safety. Table 24-5: Mt Todd WTP Effluent Goals Analyte Unit CSW2 TV CWTP Effluent Goal Magnesium mg/L 1 2.5 12.5 10 Sulphate mg/L 1 129 982 N/A Aluminum μg/L 622 55 55 44 Cadmium μg/L 0.1 0.2 0.87 0.69 Cobalt μg/L 0.1 90 680 544 Chromium μg/L 1 1 1 0.8 Copper μg/L 2 1.4 1.4 1.12 Manganese mg/L 0.024 1.9 14.4 11.5 Nickel μg/L 1 11 78 62.4

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 353 Analyte Unit CSW2 TV CWTP Effluent Goal Lead μg/L 1 3.4 19 15.2 Iron mg/L 1.1 0.3 0.3 0.24 Mercury μg/L 0.05 0.6 4 3.2 Zinc μg/L 8.65 8 8 6.4 The background water quality concentration at SW2 for aluminum, chromium, copper, iron, and zinc may exceed the site specific TV. In these cases, the WTP will remove the constituent to the TV prior to discharge. WTP effluent will also be used in the process plant for process water and around the site as dust suppression. It is assumed that the water quality requirements for environmental discharge will be satisfactory for these other uses as well. INFLUENT WATER QUALITY AND TREATMENT The geochemistry report presents expected water quality at the equalization pond upstream of the water treatment plant in the wet season and dry season for each of the 13 operating years of the mine. The geochemistry model includes inputs from various sources on the mine site, and considers any potential chemical reactions between the various inputs prior to entering the WTP. At the WTP, Vista is interested in treating the worst-case scenario. Table 24-6 presents the maximum value for each chemical constituent of concern, and compares it to the WTP effluent goal. Table 24-6: Anticipated Influent Water Quality at the WTP Analyte Unit WTP Influent Effluent Goal % Reduction Required Magnesium mg/L 195.3 10 94.9% Sulphate Mg/L 2022 N/A - Aluminum μg/L 27,940 44 99.8% Cadmium μg/L 60 0.69 98.9% Cobalt μg/L 684 544 20.4% Chromium μg/L 1.1 0.8 27.2% Copper μg/L 4,600 1.12 99.9% Manganese mg/L 9.63 11.5 0% Nickel μg/L 646 62.4 90.3% Lead μg/L 26.8 15.2 43.3% Iron mg/L 0.28 0.24 14.3% Mercury μg/L 3.2 - Zinc μg/L 12,732 6.4 99.9% The water treatment process is designed to meet the reductions as shown in Table 24-6. Water to be treated at the site will be collected in the PWP. Collected wastewater will flow by gravity from the PWP to the Feed Pump Station. The pump station is adjacent to the PWP and uses concrete wet well construction. Two wet wells (for redundancy) will each house two submersible feed pumps. The Feed Pump

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 354 Station pumps the collected water to the WTP building for treatment. The WTP process will consist of hydrated lime and chemical precipitation and high rate sedimentation, followed by filtration to remove remaining solids to meet effluent goals. Two identical treatment trains will provide full redundancy at the WTP at 250 m3/hr, with a maximum available treatment capacity at 500 m3/hr. Expected capital costs are presented in Table 24-7. All prices are given in US$ unless otherwise noted. Costs in the table include the equipment cost and an installation cost of approximately 30% of the capital cost of the equipment. Table 24-7: Opinion of Probable Capital Costs Parameter Cost (US$) Feed Pumps 59,000 High pH Sludge Pumps 33,000 Neutral pH Sludge Pumps 13,000 Treated Water Pumps 42,000 Dust Suppression Pumps 4,000 High Density Lime Clarifier Package System 2,352,000 Sodium Hydrosulfide (NaSH) Reaction Tanks 1B & 2B 138,000 NaSH Reaction Tanks 1B & 2B Mixers 262,000 NaSH Clarifiers 1B & 2B 590,000 Neutral pH Reaction Tank 1C & 2C 138,000 Neutral pH Reaction Tank 1C & 2C Mixers 197,000 Pressure Filters 702,000 Waste Tank Clarifiers 1 & 2 525,000 Treated Water Holding Tank 171,000 Ferric Chloride Feed System 73,000 Lime Feed System 996,000 Lime Metering Pumps 29,000 Polymer Feed System 29,000 Sodium Hydrosulfide Feed System 29,000 Sulfuric Acid Feed System 50,000 Earthwork 494,000 Concrete 227,000 Pre-engineered Building 1,411,000 Electrical and Instrumentation 2,016,000 Piping, Pipe Supports, and Valves 1,472,000 Engineering, Procurement, Construction 1,247,500 Contingency 1,422,000 Cyanide Probes 6,500

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 355 Parameter Cost (US$) HCN Gas Alarms 13,000 Total 14,741,000 The opinion of probable operating costs consist of electricity, labor and chemical consumption. The estimated electrical use at the site is 2,254,000 kWh annually. The estimated labor use at the site includes one (1) supervisor/certified operator and two and a half (2.5) maintenance personnel. Table 24-8 presents the probable annual chemical consumption for the Mt Todd WTP during average flow conditions. All prices are given in US$ unless otherwise noted. Table 24-8: Opinion of Probable Annual Chemical Consumption Date, Month and Season Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Chemical Wet Wet Wet Wet Dry Dry Dry Dry Dry Wet Wet Wet Ferric Chloride tonne 40 42 42 41 36 29 24 23 22 23 31 35 Lime tonne 172 180 181 176 154 124 104 100 97 100 132 151 Sodium Hydrosulfide tonne 1.7 1.8 1.8 1.8 1.5 1.2 1.0 1.0 1.0 1.0 1.3 1.5 Sulfuric Acid m3 12.1 12.6 12.7 12.3 10.8 8.7 7.3 7.0 6.8 7.0 9.2 10.5 24.2.2.3 Raw Water Reservoir and Pipeline The Raw Water Dam (RWD) is the sole source for potable and elution water, as it is the only freshwater source on site. The RWD reservoir provides storage of fresh water for use at the mine and processing facility. The reservoir is on a tributary of Horseshoe Creek, located north and east of TSF 1, and retains a reservoir storage volume of approximately 4.5 million cubic m. The RWD reservoir provides a ready supply of fresh water for several uses. The water balance indicates that process water obtained from recycled process water and TSF decant water will need to be supplemented, particularly in the dry season. The RWD reservoir can also provide water for dust control and onsite potable water supply. Dust control will be needed during the dry season on roads and exposed soil surfaces around the project site. The reservoir generally fills in the wet season (November through April) and will be used during the dry season (May through October). It can also supply wet season fresh water, if needed. The existing dam is a 13-m high, 114-m long, zoned-embankment dam with a low-level outlet and a spillway. The outlet works are connected to the fresh water pipeline that extends to the process plant. The spillway is designed for the flood- event discharges to Horseshoe Creek. The existing line from the RWD will need to be augmented with an additional 250 mm line to provide the proper volume of water for the higher throughput. The Raw Water Pipeline is described in Section 18.2.1.2 – Sub-Area 4120 – Raw Water.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 356 24.2.2.4 Potable Water Potable water will be produced by a potable water treatment plant within the processing facility, and will be distributed to the process plant, mining, administration offices and laboratory facilities. Drinking water quality guidelines that may be relevant to the Project include the Australian Drinking Water Guidelines (ADWG). These guidelines are intended to provide a framework for good management of drinking water supplies that will assure safety at point of use (NHMRC and NRMMC, 2004). 24.2.2.5 Sanitary Sewer System The sanitary sewer system will consist of gravity lines conveying the sewerage to a single sewer lift station. The lift station will then pump the sewer to the septic system for treatment. The effluent will flow by gravity to a leach field. 24.3 Geochemistry Tetra Tech was commissioned by Vista to conduct geochemical characterization studies and predictive modeling in support of the Project Technical Report. Waste rock samples were selected from the three distinct rock units identified from the 18 mappable rock codes present at the site, specifically: „ Greywacke; „ Shale; and „ Mixed greywacke/shale (interbedded). Eighty-seven waste rock samples were subjected to acid-base accounting (ABA), to assess the acid-producing and acid-neutralizing potential of overburden and waste rock prior to mining or other large scale excavations. Nine samples, including three samples from each of the three distinct units were selected for kinetic testing using humidity cell tests. This test provides an estimation of chemical leaching of the samples under oxidizing conditions and is useful in determining the effect of natural weathering of said materials during and post- mining. Mineralogy was determined by quantitative x-ray diffraction (XRD) on the nine humidity cell test samples. The greywacke waste rock sample average extractable (sulfide) sulfur content was 0.19 wt. % utilizing a nitric acid leach (HNO3). This was comparatively low as the interbedded and shale samples were 0.51 and 0.31 wt. %, respectively. Hydrochloric acid (HCl) extractable (sulfate) sulfur was largely absent suggesting that minimal sulfide oxidation occurred prior to geochemical characterization. On average, insoluble sulfur made up approximately 30% of the sulfur distribution in the 87 samples that underwent ABA testing. The average sulfur content of the waste rock samples was ≤ 0.51 wt. % HNO3 extractable sulfide sulfur; however, the potential for acid formation cannot be discounted due to the limited amount of neutralization potential (NP) in the rocks. On average, the samples showed an NP ≤ 11 kg CaCO3/tonne rock. An acid base accounting (ABA) neutralization potential ratio (NPR) screening criteria of < 2 suggests that a majority of the waste rock samples are either potentially acid generating or highly likely to generate acid. Waste rock comprised of these samples may require isolation from surface and/or ground water to inhibit acid generation. It should be noted, however, that approximately 30% of the samples are highly unlikely to generate acid. These samples contained high insoluble sulfur (> 30 wt. %) which are tied up in sulfide species that are resistant to chemical weathering such as sphalerite (ZnS) and/or galena (PbS).

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 357 Preliminary sulfur cutoff criteria were developed based on ABA and Net Acid Generation (NAG) pH results, to assist with waste rock management and closure planning. The specific sulfur cutoff values utilized to predict increasingly acid generating risk are: „ Non-PAG waste rock is defined by total sulfur content from 0.005 wt. % through 0.25 wt. %; „ Waste rock with uncertain acid generation potential ranges from 0.25 wt. % through 0.4 wt. % total sulfur; „ The total sulfur content of PAG waste rock is > 0.4 wt. %; and „ Waste rock with > 1.5 wt. % sulfur was considered to be likely acid generating. These cutoffs were used for geochemical modeling of the WRD seepage and pit lake wall rock runoff and can be used in combination with the total sulfur block model based on the exploration database to assist with proper routing of waste rock. The nine waste rock samples selected for kinetic testing were subjected to humidity cell testing. Weekly leachate quality results were obtained for pH, acidity, alkalinity, electrical conductivity, and sulfate over the entire test duration. Monthly leachate composites for dissolved constituent concentrations were also obtained over the testing period. Of the nine samples subjected to kinetic testing, a shale sample with 0.43 wt. % HNO3 extractable sulfide sulfur and low NP = 3.7 kg CaCO3/tonne rock produced acidic leachate (pH < 6) from the initiation of testing. Elevated copper, lead, nickel, and zinc levels were observed in leachate from the acid generating cell. The remaining humidity cells produced circumneutral pH values, with relatively low concentrations of metals. However, it is anticipated that given ample time these cells will likely produce acidic leachate and concomitant increased metal concentrations. Two tailings samples underwent geochemical characterization including ABA, mineralogy, water leaching, and supernatant analysis. These samples contain 1.25 wt. % and 1.13 wt. % total sulfur with net acid production potential (NAPP) and NPR values that show the tailings have potential to eventually generate acid. Humidity cell testing was conducted on one of the samples. However, the tailings supernatant and water leach testing produced alkaline pH values. Concentrations of some metals/metalloids, major ions, and cyanide in the tailings supernatant were above ANZECC water quality guidelines, whereas levels were lower in the water leachate but some metals and metalloids and cyanide remained elevated above the guidelines. After 32 weeks, kinetic testing of one of the samples shows a neutral pH with low concentration of metals. Calculations indicate that abundant sulfide sulfur still remains, suggesting the sample has the potential to produce acidic leachate given ample time and continued chemical weathering. Predictive geochemical modeling was conducted to determine the production phase water quality of the WTP Process Water Pond. The water quality estimates were used as a basis for the WTP design and further assist with LoM site water management planning. Inputs to the Process Water Pond included precipitation and inputs from ponds/facilities from across the site including: „ RP 1 – WRD Retention Pond; „ RP 2 – Low Grade Ore Stockpile Retention Pond (LGRP); „ RP 3 – Batman Pit; „ PWP – Process Water Ponds; „ HLP – Heap Leach Pad Pond; and „ RP 7 or RP 8 – the TSF 1 or TSF 2 Ponds; and „ Precipitation.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 358 Biannual water quality estimates suggest the Process Water Pond may potentially be acidic, with a majority of metal concentrations above the ANZECC water quality guidelines. Metal concentrations fluctuate depending on the relative input source proportions reporting to the Process Water Pond. In order for Vista to re-commence mining activities, the water in RP3 must be lowered to a level below where mining is scheduled to occur. Treatment of RP3 by micronized lime has been conducted with success, with pH levels becoming circumneutral with a general decrease in metal concentrations that are sufficient for discharge under WDL 178-07 during the wet season. 24.4 Surface Water Hydrology The Project Site is drained by the perennial Edith River, located approximately 1 km south of RP 1, and also drained by several ephemeral streams, namely: Batman Creek, which bisects the center of the site, and Horseshoe Creek, which is located east of the site. Both Batman and Horseshoe feed Stow Creek, which enters the Edith River at a location south of the discharge point from the Waste Rock Dump Retention Basin (RP 1). Horseshoe Creek and Batman Creek catchments are approximately 45 and 11 km2, respectively. The RWD was built across Horseshoe Creek immediately above the mine, forming a sub-catchment covering about 55% of the Horseshoe Creek catchment. The remainder of the Stow Creek catchment is approximately 144 km2 and is not impacted by mining activity. Stow Creek flows for a short distance after its confluences with both Batman Creek and Horseshoe Creek, prior to joining the Edith River. The catchment area of the Edith River upstream of Stow Creek confluence is approximately 540 km2. Surface water at the site is well-documented and its management has been the object of study by both Vista and the NT Government in recent years. Historically, flows from the mine have exceeded the capacity of the water management system, thus allowing uncontrolled discharges to the Edith River. The effectiveness of the water management system has improved as a result of revisions to the pumping systems, installation of a stage height and telemetry station at SW4 and a flow meter on the siphon and pumping outlets from RP 1. Additionally, the NT Government completed a raise of the spillway crest and dam at RP 1 by 1.5 m. Drainage from the Project Site enters the Edith River at two locations: discharge point for RP 1 and West Creek. The RP 1 discharge point is located 0.8 km below the Stow Creek and the Edith River confluence. West Creek joins the Edith River approximately 1.5 km below the Stow Creek and the Edith River confluence. West Creek delivers water diverted from the undisturbed, natural terrain on the western side of the WRD via the Western Diversion Drain, and overflow from the RP 1 spillway. The West Creek catchment is small and it is reported that the creek only delivers mine water to the Edith River after substantial rainfall events exceed capacity at RP 1. During the wet season (approximately November to April) uncontrolled discharges to the Edith River could occur from any or all of the following during high rainfall events: the WRD Retention Pond (RP 1), the Low Grade Ore Stockpile Retention Pond (LGRP) and the Process Plant Retention Pond (PRP). However, for a large part of the year (approximately May to October), no runoff from the mine area enters the Edith River. 24.5 Regional Groundwater Model and Mine Dewatering The Project will enlarge the existing Batman pit significantly below the water table. After the existing pit has been emptied, the pit is expected to require additional dewatering as mining progresses. Historical data indicate that the primary driver for dewatering design will likely be runoff entering the pit from precipitation during the wet season, rather than groundwater inflow.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 359 The following sections provide a brief summary of the applicable hydrogeologic information, historical observations, and conceptual pit inflow model. This information and surface water hydrology information provide the basis for the dewatering cost estimate. Geologic information related to the geological setting, mineralization and exploration of the project site was presented in Sections 7.0 – Geological Setting and Mineralization, 8.0 – Deposit Types, 9.0 – Exploration, and 10.0 – Drilling; the geologic information in this section is presented from a hydrogeologic perspective as it relates to groundwater flow and pit dewatering. 24.5.1 Regional and Site Hydrogeology In the Mt Todd area, bedrock occurs either at the surface or, in some valleys and streambeds, beneath a thin layer of alluvial sediment. The 1:250,000 regional geologic map of Katherine, NT2 indicates that the formations in the vicinity of the BP are the Finniss River Group (Burrell Creek and Tollis Formations) and the Cullen Batholith (specifically the Yinberrie and Tennysons Leucogranites). The Finniss River Group consists of greywacke, siltstone, and shale, interspersed with minor volcanics. Bedding normally strikes at 325° and dips 40° to 60° to the southwest. The Finniss River Group strata have been folded about north-trending F1 fold axes. The folds have moderately west-dipping axial planes, with some sections overturned. The rocks exhibit varying degrees of contact metamorphism which increases with proximity to the intrusive units of the Cullen Batholith. In the vicinity of the Project, metamorphism is typically noted as silicified or hornfelsed material. The existing Batman pit is located in the Burrell Creek Formation, approximately 2 km from the surface expression of the Cullen Batholith units. However, at the proposed final depth of the pit, the contact has been shown to be only a few hundred meters west of the pit. Thus, the materials encountered during drilling in the immediate vicinity of the pit are typically hornfelsed or silicified greywackes and siltstones with almost no primary porosity. East-west trending faults and joint sets and north-south trending quartz sulfide veining crosscut the bedding. The faults exhibit only minor movement. While there is little primary porosity in the bedrock of the Mt Todd area, the weathering profile is extensive. In the late 1980s and early 1990s, when the existing Batman pit was under development, a number of production and monitoring bores were installed3. These bores are located both near the pit and up to 4 km north and south of the pit. In addition, Vista has advanced a number of boreholes both for exploration and geotechnical evaluation. The borehole logs generally indicate that the upper 3 m are unconsolidated. Below that, weathering typically extends to approximately 30 m below ground surface (m bgs), with the degree of weathering decreasing with depth. The Mt Todd area experiences heavy rainfall during the wet season. The average rainfall is 1,129 mm/year, but more than 80% of it falls from December through March. Thus, anecdotally, sheet flow of precipitation runoff occurs as the thin crust of soil and alluvial material reaches saturation. During heavy rain events and for some time afterward numerous ephemeral streams develop in the valleys. These subsequently stop flowing during the dry season. The conceptual model of groundwater flow is that nearly all of the precipitation becomes runoff. Of the precipitation that does infiltrate, most flows within the upper 3 meters of unconsolidated material toward the nearest valley, where it feeds the stream system. Within the valleys, flow occurs as surface water in the streams and also within the thin layer of alluvium beneath and adjacent to the streams. Within bedrock, most water is believed to flow in the weathered profile, through fractures. The regional flow of groundwater is generally from higher to lower elevations. 2 National Geoscience Mapping Accord, Katherine (NT), Sheet SD 53-9, Second Edition, 1994. 3 Rockwater, 1994. Mt Todd Gold Mine, Bore Water Supply Expansion Programme Bore Completion Report.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 360 24.5.2 Regional Numerical Groundwater Flow Model Tetra Tech constructed a regional numerical groundwater flow model to estimate groundwater inflows to the open pit at Mt Todd and potential impacts to regional and local water resources. The model uses the finite- difference model code MODFLOW-SURFACT, which is widely accepted and commonly used for such applications. The model is regional in scale and incorporates hydraulic properties for regional and local geologic units as derived from on-site testing, precipitation-derived recharge, natural and man-made surface hydrologic features such as ephemeral and perennial streams, the RWD, TSF, WRD, and the existing Batman pit. The proposed enlargement of the Batman pit is incorporated into predictive simulations of groundwater inflows to the pit and post-mining recovery of the groundwater system. Although preliminary calibration of the regional groundwater model has been completed, additional calibration is required and the model has not yet been finalized. Thus, only preliminary estimates of groundwater inflow to the expanded Batman pit and post-mining groundwater system recovery are currently available. The model will be finalized and used to generate updated estimates of dewatering flows and dewatering effects on the groundwater system for the feasibility study. For this Technical Report, Tetra Tech developed preliminary estimates of groundwater discharge into the pit based on preliminary model output coupled with historical observations (discussed below). Preliminary estimates from the groundwater modeling conducted to date suggest that groundwater inflows should initially be approximately 3 m3/hr and will gradually increase as the pit is enlarged and deepened, reaching a cumulative average rate of approximately 75 to 120 m3/hr during the latter part of Phase IV. Under expected normal conditions, a portion of the groundwater inflow would be removed by evaporation from the pit walls and floor. Pit dewatering is expected to lower groundwater levels in the vicinity of the pit. The preliminary modeling suggests that dewatering-related water level declines of 1 m or more should not extend farther than approximately 300 m from the pit. 24.5.2.1 Historical Observations During the development of the existing Batman pit, very little dewatering was required. The following observations were made: „ In 1994, one bore (BW-30P) was installed to provide dewatering capability if needed for the pit. This bore targeted a production zone between 36 and 50 m bgs and was expected to yield up to 600 cubic m per day (Rockwater, 1994). „ Bore BW-30P may never have been used, since in 1997 a dewatering investigation indicated that the method in use was sumps and sump pumps (Dames & Moore, 1997). The geologic materials exposed in the pit were identified to have an extremely low primary permeability but slightly higher secondary permeability along fractures, bedding planes, and joints. „ In December 1999 to January 2000, a geotechnical investigation described minor seepage on bedding planes and more consistent seepage in the southwest, northwest, and northeast corners of the pit (Pells Sullivan Meynink Pty Ltd., 2000). These seepages were related closely to rainfall and were greatly diminished in the dry season. However, these seepages did not appear to raise any concern at the time with respect to water removal. The Batman pit operations were shut down in June 2000. Vista personnel visited the site in June 2006 and reported that only 1.5 m to 2 m of water was present in the bottom of the pit, despite the pit floor being approximately 90 m to 100 m below the water table near the pit. Considering that no dewatering had been done in the intervening six years, groundwater inflow is expected to be small and, therefore, a relatively minor component of dewatering.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 361 While the groundwater inflow component is expected to be relatively minor, precipitation during the wet season has historically been significant, especially on a short-term basis. Monthly reports prior to June 2000 indicate that on several occasions large storm events generated sufficient storm-water inflow to interrupt mine operations. One event in particular resulted in the pit floor being inaccessible for approximately a month (General Gold Operations Pty Ltd (GGO), 2000). Thus, a dewatering plan will be required to ensure that surface water runoff and precipitation inflows do not significantly hamper consistent mine operation. 24.5.3 Inflow Estimates As noted above, groundwater inflow is expected to be a relatively minor component of dewatering. However, the large amount of precipitation and storm-water runoff has historically been a cause for concern. Therefore, for the PFS level dewatering design, the role of groundwater inflow has been assumed to be negligible, and storm-water runoff is the primary consideration for pit dewatering design. While negligible in terms of dewatering system design, groundwater inflows are more continuous than storm-water inflows and hence are significant relative to estimation of dewatering operating costs. Thus, Tetra Tech based the conceptual dewatering plan on the 10-year recurrence interval, 72-hour and 100- year recurrence interval, 24-hour duration storm events. The precipitation values for those storm events, as obtained from the Bureau of Meteorology (BOM, 2017), are 3.47 mm/hr for 72 hours, which results in a total amount of 249.84 mm, and 10.7 mm/hr for 24 hours, which results in a total amount of 256.80 mm. The precipitation is assumed to fall uniformly over the pit and its catchment area. As the pit increases in size during mine development, the catchment area outside the pit would decrease until the pit comprises the entire drainage area in Phase II. Total volumes of storm water runoff inflow to the pit at the end of each phase of mine development are listed in Table 24-9. The volumes were calculated using the SCS Curve Number method (USDA, 1996). Table 24-9: Catchment and Pit Areas, Inflow Volumes, and Dewatering Times for Mine Dewatering Design Mine Phase Catchment Area (m2) Inflow Volume (m3) Days to dewater pit after 10-year storm event1 Phase I 569,000 134,676 14 Phase II 738,787 176,479 19 Phase III 973,336.3 232,508 25 Phase IV 1,251,963 299,065 32 1 At pumping rate of 500 m3/hr 24.5.4 Mine Dewatering Dewatering of the proposed Mt Todd Mine Batman Pit is anticipated to be through passive collection of water in the pit floor sump. The sump would collect surface water, pit wall run-off and precipitation, as well as groundwater inflow. Table 24-9 shows the days to dewater the pit after a 10-year storm event for each phase of pit development at a 500 m3/hr pumping rate. The design pumping rate does not increase throughout the LoM; instead, the time it takes to dewater the pit after a storm event increases. The dewatering system has been sized to 700 m3/hr and reports to the PWP.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 362 Sump water would be removed through pumping and discharge lines to the pit rim and ultimately to the PWP. Water pumped from the pit floor would first go through a pair of pumps mounted on pontoons and then through skid mounted booster pumps placed at 96-120m lifts. Lifts with booster pumps will be added in stages with increasing pit depth. Once at the surface, the water would be piped to the PWP. Figure 24-1 shows the pit floor pump, booster pumps, and pipeline conceptual design, and Figure 24-2 shows the conceptual layout of the dewatering system. Costs for dewatering are provided in Section 22.0 – Economic Analysis. The mine dewatering system may require modification and refinement as empirical data become available during advanced exploration and initial mine construction and operation. In particular, groundwater-related mine inflow estimates should be refined based on numerical model updates incorporating observed groundwater inflow rates to the pit and observed water level changes in groundwater monitoring bores at the site.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 363 Figure 24-1: Open Pit Dewatering System Conceptual Design

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 364 Figure 24-2: Conceptual Layout of Dewatering System

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 365 24.6 Project Implementation 24.6.1 Project Implementation Strategy This section outlines a high level Project Development Strategy, which will be further developed during the next study phase of the Project. The Technical Report definitions of Scope, Cost and Schedule have been established on the presumption that Vista will implement the Project utilizing the Engineering, Procurement and Construction Management (EPCM) Execution model. Vista will appoint an EPCM Contractor (Engineer) with the prerequisite capability and experience to undertake the work. To complement the EPCM approach, Vista will adopt Design and Construct (D&C) implementation strategies, for select areas of the Project. Properly executed, the EPCM Execution strategy will afford Vista the following benefits: „ Lower Capital Cost Outcomes „ Project Implementation flexibility „ Fast-Track Execution opportunities „ Flexible Project Funding Strategies „ Optimal Project Quality Outcomes 24.6.2 Project Organization 24.6.2.1 EPCM Contracts Vista’s Project Manager will direct all activities including EPCM and D&C Contractors. For the EPCM Scope, two organization charts are developed: „ EPCM Stage 1 – Design & Procure. Refer to Figure 24-3. „ EPCM Stage 2 – Construct & Commission. Refer to Figure 24-4.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 366 Figure 24-3: EPCM Stage 1 – Design & Procurement. Refer Diagram 1

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 367 Figure 24-4: EPCM Stage 2 – Construct & Commission. Refer Diagram 2

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 368 24.6.2.2 D&C Contracts Two D&C contracts are proposed, specifically: „ Non Process Infrastructure (NPI) – Transportable Buildings (Package C160); and „ NPI – Site Erected Buildings (Package C170). 24.6.2.3 EPCM Contract Scope of Services Generally, the Engineer will perform the following tasks: „ Detailed process, civil, structural, mechanical and electrical design; „ Establish a document control system; „ Preparation of specification documentation; „ Calling and review of tenders for supply and installation of equipment; „ Contract evaluation, negotiations, documentation and management; „ Preparation of Purchase Orders and Contracts; „ Quality audits of major contractors and manufacturers; „ Construction management; „ Equipment and site inspections; „ Cost control, procurement, scheduling and planning, contract administration; „ Regular reporting on progress against schedule and cost against budget; „ Site testing and commissioning; and „ Preparation and review of Operation and Maintenance manuals. 24.6.3 EPCM Management The Engineer will provide an experienced and suitably qualified Project Manager who will manage all aspects of the EPCM Contract. The EPCM Manager will be the single point of contact for the Vista Project Manager and will work closely with the Vista senior managers and other Project Managers associated with the project. 24.6.4 Engineering The Engineer will provide an experienced and suitably qualified Engineering Manager who will manage discipline-based groups of Engineers and Draftsmen that will be responsible for coordination, direction, administration and completion of all detail design. Effort will be primarily aimed at optimizing design, uniformity and quality of design and monitoring of time spent against budget. Where Engineering Design is undertaken, progress will be reported by the Engineering Manager through the EPCM Project Manager to the Vista Project Manager. 24.6.5 EPCM Controls Using the Feasibility Study report as the basis for project scope and the capital cost estimate as the control budget in the first instance, the project will be managed in accordance with the Project Schedule submitted in the Study report. Initial activities will be directed to the awarding of Construction Contracts and/or Supply Contracts for long lead time items of plant and equipment, immediately upon Vista’s approval to proceed. The budget and schedule will be continually updated to reflect the current understanding of the project status.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 369 The Engineer’s Project Controls group will report to the EPCM Project Manager and will have responsibility for the following activities: „ Monitoring and reporting of contract package progress. This will be performed on a daily basis as necessary and reported weekly/fortnightly/monthly as required by means of the Procurement Status Report. „ Definitive estimate maintenance and forecasting. Records of variations to budget and other forecast estimates of cost to completion will be updated as necessary and reported by means of the Cost Control Report Summary. „ Cost control for procurement and contracting. Actual costs (invoiced and payments made), committed costs (orders placed) and estimated costs will be reported against budget using the Cost Control Report. The Trend Notice/Scope Change Notice system will be incorporated with these activities to ensure accurate forecasting. „ Coordination of construction planning and scheduling. Weekly meetings of all TTP-controlled site contractors’ Project Managers will be held to coordinate changes, clashes and priorities between contractors. „ Maintenance of an overall Schedule. The Schedule will be formatted using the WBS information received from all contractors and will be updated using information obtained from the various contractors and reviewed by the Project Manager on a weekly basis as a minimum. „ Project reporting. A monthly project progress report will be issued including, but not limited to, the following information: Highlights for the reporting period ⎯ Safety, Health and Environment issues; ⎯ Overall project status; ⎯ Engineering progress; ⎯ Procurement and fabrication progress; ⎯ Construction activities; ⎯ Planned activities for the next reporting period; ⎯ Current project cost reports; ⎯ Outstanding issues, Variations, Technical Queries, etc.; ⎯ Project S-curves; and ⎯ Photographs depicting project progress. 24.6.6 Procurement 24.6.6.1 Procurement Strategy The key procurement aims and objectives are to: „ Achieve the project objectives of earliest possible completion, cost-effective execution, quality workmanship and high degree of safety from suppliers. „ Adhere to the project plan, aims and schedule. „ Ensure that commercial and schedule risks are at acceptable levels. „ Provide a purchasing environment that minimizes claims and protracted disputes.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 370 „ Provide a procurement arrangement that encourages suppliers to be innovative and efficient. „ Carry out the procurement function for the project in an ethical and professional manner. Key success factors are to: „ Meet or exceed expectations for health and safety requirements. „ Meet or better the project schedule. „ Meet or better the project budget. „ Meet project quality objectives. 24.6.6.2 Procurement Overview The Engineer’s Procurement Manager will report directly to the Engineer’s EPCM Project Manager but will also liaise directly with Vista’s Commercial Manager. The Engineer’s Procurement Manager will be responsible for the preparation, all approvals and proper implementation of the Project Procurement Plan. Prior to the project receiving all necessary approvals (Vista and Statutory), award of clearly identified and specified packages containing long lead time delivery items will only be initiated by written authorization from Vista. The Engineer’s Procurement Manager will adhere to Vista’s procurement policy and procedures in place at the time with regard to authorization levels for capital expenditure and the requirements to obtain competitive quotations at discreet capital expenditure levels. All packages for supply of all project related goods and services will be prepared, tendered, assessed and awarded by the Engineer’s Procurement group. All purchase orders and contracts will be prepared by the Engineer’s Procurement group but issued through Vista’s purchasing system. Where goods and services are required from outside Australia, the Engineer’s Procurement Manager will ensure, through liaison with Vista, that sufficient forward cover on foreign exchange transactions is in place to mitigate any risk of currency fluctuation. 24.6.6.3 Construction Packages The Engineers Procurement Manager will be responsible for the development of a Construction Contracting Strategy. A preliminary strategy is documented in the Contracting and Procurement Plan.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 371 The following Construction packages are envisaged as a minimum: Table 24-10: Construction Packages Package No. Package Description C015 Demolition Works C020 Bulk Earthworks C025 Power Plant C030 Construction Camp C032 Camp Management C035 Tailings Dam C040 Roads, Drainage & Fencing C045 Concrete Supply C050 Concrete Works C055 Water Treatment Plant C060 Structural Mechanical and Piping Installation C070 Site Erection of Field Tankage C080 Electrical and Instrumentation Installation C090 Control System - Install & Commission C100 Fuel Farm C110 ANFO Facility C120 Fire Systems C140 Power Lines Reticulation C160 NPI Transportable Buildings C170 NPI Site Erected Buildings C180 Communications – Telstra Interface C190 Communications – Temporary

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 372 24.6.6.4 Supply Packages The Engineers Procurement Manager will be responsible for the development of an Equipment and Services Supply Contracting strategy. The following supply packages are envisaged as a minimum: Table 24-11: Supply Packages Package No. Package Description P001 Ball Mills P030 Secondary Grinding Mills P002 Primary Crusher P003 Secondary Crushers P004 HPGRs P005 Dry Screens P006 Wet Screens P007 Slurry Pumps P008 Solution Pumps P009 Apron Feeders P010 Belt Feeders P011 Cyclone Clusters P012 Agitators P013 Thickener P014 Inter Tank Screens P015 Carbon Transfer Pumps P016 Gold Room P017 Vibrating Feeders P018 Container Tippers P020 Flocculant Mixing Package P021 Lime Slaker P023 Potable Water Plant P024 Mill Relining Machine P025 Overhead Travelling Cranes P026 Air Compressors, Driers & Receivers P028A Conveyor Drives P028B Conveyor Pulleys P028C Conveyor Idlers P028D Conveyor Belts & Splicing P028E Conveyor Skirts

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 373 Package No. Package Description P028F Conveyor Scrapers & Ploughs P029 Ore Sorting P031 Wet Scrubber P032 Isolation Gates P033 Ventilation Fans P034 Screw Feeders P035 Rotary Valves P036 Filters P038 Hoists P039 Ball Charging Magnets P040 Tramp Magnets P041 Sump Pumps P042 Firewater System P043 Weightometers P045 Samplers P046 Analyzers P047 Rock Breaker P048 Blowers - Detox P049 Metal Detectors P050 FRP Tanks P051 Winches P053 Manual Valves P054 Laboratory Equipment P055 Bag Splitters P056 Safety Showers P057 Pressure Relief Valves P058 Pressure Regulators P060 Weighbridge P101 HV Switchgear P102 HV Cables P103 Transformers P104 Motor Control Centers (MCCs) P105 HV Variable Speed Drives P106 Neutral / Earth Resistors P107 Overhead Power Lines P108 Control System - Supply

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 374 Package No. Package Description P109 Instruments P110 Switchrooms/MCCs P111 LV Variable Speed Drives P112 Power Factor Correction / Harmonic Filters P113 Control Valves P114 CCTV P115 2 way Radios P116 Plant Fire Detection Systems P117 RMUs/Kiosk Substations P118 Spares P119 Telemetry P120 Emergency Power P121 Security P122 UPS P123 WAD Cyanide Analyzers P124 HCN Monitors P125 Data Room P126 Motors P200 Fabricated Structural Steel Work P210 Fabricated Platework 24.6.6.5 Indirect Packages The Engineer’s Procurement Manager, in collaboration with Vista, will establish and manage a series of Indirect Packages. The Indirect Packages are envisaged as a minimum: „ EPCM Services „ Environmental Consultants „ Human Resources (HR) & Industrial Relations (IR) Consultants „ HSEC Consultants „ Commissioning „ Licenses, Fees and Legals „ Project Insurances „ Pre-Production Costs „ Capital Spare „ Stores and Inventories „ Heavy Lift Cranage

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 375 24.6.6.6 Expediting The senior expeditor will plan and control expediting activities in consultation with procurement, establishing material status reports and ensuring suppliers comply with agreed delivery of drawings, data, materials and equipment. The post-award responsibility for the Supply Contract is vested with expediting; however, commercial responsibility stays with the purchasing officer. Expeditors will anticipate and act at the earliest possible stage to eliminate or reduce delays which may impact on the project schedule. Manufacturing and delivery progress will be monitored and reported to the project via expediting status reports. Status reports will verify the milestones reported. Exceptions will be reported to management. These reports will detail actions being taken to resolve any issues causing concern. The senior expeditor will utilize global support offices of a worldwide expediting third-party provider if necessary, to achieve the project schedule. 24.6.6.7 Logistics and Transport The Engineer will be responsible to manage the consignment of equipment and materials to the Project Site in the Northern Territory. A proven international project freight forwarding group with a global network will be appointed early in the project to provide logistics support services and to aid in the preparation of the transport and logistics plan. The focus will be on the most cost effective solution for delivery to site of equipment and materials to meet the construction schedule. The logistics specialist will develop a transport plan to be used to manage the sea, road and airfreight costs to budget. Selected land transport subcontractors will be required to display the necessary capabilities and dedicated management that will ensure equipment is suitable and operators take every precaution to meet the project safety and quality requirements. Transport plans will be prepared for all equipment based on maximum project transport envelopes. The review of the bulk steel supply will contribute to the plan. The plan will include, but not be limited to: „ Functional requirements of an inbound logistics system; „ Assessment of existing transport nodes and linkages (ports, roads and rail); „ Maximum load length, width, height and weight restrictions; „ Specialist heavy-lift and over-dimensional transport requirements at port, for example, liaison with statutory authorities and utilities, permitting, road closures and escorts; „ The requirement for “holding facilities” at port to manage the storage of equipment, materials and bulk steel pending transport to site; „ The movement of over-size components to site; „ Assessment of site conditions; „ Identification of alternative operational model; methodologies, constraints and risks; and „ The identification and management of shipping container and other demurrage costs. The freight forwarder (or an independent consultant) will specifically review the movement of the bulk steel supply from place of manufacture to project site.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 376 24.6.7 Construction Management The Engineer’s Construction Manager will establish a small on-site team prior to construction contractors mobilizing to site. The exact timing of the team’s establishment will be dependent on feedback from contractors regarding progress off site, but site establishment should not be less than four weeks in advance of contractor mobilization. The Engineer’s Construction Manager will ensure that all construction contractors are responsible for: „ Maintaining a safe site; „ Maintaining compliance with all appropriate Statutory and Legislative requirements; and „ Maintaining compliance with all Vista site requirements in regard to Environmental Health and Safety of the construction work force and the supervising team. All site works will be undertaken utilizing qualified construction contractors, and the Construction Manager will act in the role of Superintendent to Vista when administering the construction contracts. The construction supervision team will comprise of suitably qualified and experienced personnel and, where possible, preference will be given to more senior professionals when selecting staff, recognizing that the construction schedule and budget are of significant importance. 24.6.8 Commissioning The Engineer will develop a Commissioning Management Plan, in collaboration with the Vista Commissioning Representative. The Engineer’s Commissioning Manager will report to the EPCM Manager, but liaise closely with Vista’s Commissioning Representative. Three Commissioning Areas are contemplated: „ Primary Crusher up to Mill; „ Mill to Gold Room; and „ Non-Process Infrastructure (NPI). Supervision of the various areas and disciplines during the discreet commissioning phases will be the responsibility of specifically appointed professional engineers assisted by key personnel from any design teams, construction teams, representatives of the various vendors and from the client’s staff. Commissioning for the Process Plant will be generally carried out in three distinct phases: „ Dry commissioning of all mechanical and electrical equipment including manual rotational checks, off load driven rotational checks, functional checks, instrument I/O checks, electrical continuity checks, etc.; „ Wet commissioning of all mechanical and electrical equipment including hydraulic pressure testing using water, coupled with flow testing using water to ensure integrity of the various pumped circuits; and „ Process commissioning of all mechanical and electrical equipment using production materials, commencing at minimum throughput requirement and gradually increasing to full design capacity prior to conducting any necessary performance testing. Refer to Figure 24-5 for Commissioning Phases bar chart.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 377 Figure 24-5: Commissioning Phases

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 378 All modifications required during commissioning will be documented in a Project Modification Register and subject to the same verification as detailed design with respect to design, fit for purpose, Environment, Health and Safety (EHS) and Hazard and Operability (HAZOP) Study requirements and drawing updates. All modifications will be carried out by either construction contractor’s representatives or vendor representatives. 24.6.9 Temporary Construction Facilities All Contractors will be responsible for the provision of their own site facilities to an appropriate standard that complies with local EHS guidelines for offices and amenities and to the approval of the Construction Manager. All contractors will be responsible for the upkeep, cleaning and sanitation requirements of their respective facilities. The EPCM Contractor will be responsible for the provision of suitable connection points for power, water and sewerage. The EPCM Contractor will be responsible for the provision of suitably located areas for the installation of the temporary facilities and for the provision of a suitably located receipt and lay-down area for delivered goods. 24.6.10 Industrial Relations All contractors will be required, under the terms of their contract, to take responsibility for their own industrial relations. They must be able to demonstrate and have in place suitable policies and procedures to ensure that the handling of matters of an Industrial Relations (IR) nature cause minimum disruption to the project schedule and budget. All contractors must be able to demonstrate compliance with the HR/IR Policy. The Plan will be incorporated into all tender documentation. This plan will also contain details of the Site Agreement on wages and conditions that will apply universally to the project. Contractors may be required to be affiliated to an equivalent Chamber of Commerce and Industry (CCI) for the Northern Territory. The CCI being a recognized and competent employer organization that can provide adequate IR advice and advocacy service, should the contractor fail to demonstrate the adequacy of his own internal services in this area. All contractors should make an allowance to retain the CCI to develop suitable IR strategies, policies and procedures that will ensure that, in the event of industrial action being taken by contractors, the resolution of such matters will be timely and of such a nature as to not adversely affect the project schedule and budget. 24.6.11 Health and Safety All contractors will be required to comply with AS 4801 (Standard for Safety Management Systems) as a minimum. All contractors must be able to demonstrate compliance with the EHS Project Management Plan. The Plan will be incorporated into all tender documentation. The Engineer, in conjunction with Vista, will be responsible for developing a safety policy during the initial phase of the project. This policy should set out guidelines for the project safety procedures and the safety

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 379 targets for the project. Particular emphasis will be placed on site attendance of project personnel and the occupation of the site by the construction team and various contractors. The policy will address the following issues: „ The legislative responsibilities of Vista and the Engineer under the relevant Occupational Health, Safety and Welfare Act; „ The legislative responsibilities of contractors under the relevant Occupational Health, Safety and Welfare Act; „ The legislative responsibilities of employees under the relevant Occupational Health, Safety and Welfare Act; „ The establishment of safety protocols and management systems required by the Act and how they will be practically implemented to suit the needs of the project; and „ Any IR issues that need to be addressed as part of the overall safety management program. All new employees attending site will be required to complete the necessary Vista site induction programs. The Engineer will employ an experienced Safety Manager for the term of the project and a Site Safety Officer for the period of site occupation. The Safety Manager will be responsible for implementing the project safety policy, developing procedures in conjunction with the Engineer’s Site Safety Officer and implementing the provisions of the relevant Occupational Health, Safety and Welfare Act. The Engineer’s Site Safety Officer will be responsible for enforcing all safety procedures and rules on the construction site and will organize regular communications with contractors to ensure adherence to policy, procedures and rules. Contractors will be required to support the project safety protocols, provide individual safety management plans, perform Job Safety Analysis and ensure their employees are provided with Personal Protective Equipment to the standard defined by the overall site policy. Contractors must also provide a nominated individual at supervisory level, who has received adequate training in Occupational Health and Safety (OH&S), who will be responsible for safety procedures within the contract. Contractors will be required to provide adequately equipped First Aid kits and have at least one formally qualified First Aid person on each shift to administer minor injuries not requiring medical attention from a Doctor. In the event of a more serious injury, Vista will make available the site First Aid facilities and personnel to all project related employees. The Engineer’s Construction Manager will ensure that adequate records are kept of all safety incidents, irrespective of whether First Aid is required. TTP’s Site Safety Officer will report Lost Time Injury Frequency Rate, Disabling Injury Frequency Rate and Medically Treated Injury Frequency Rate, along with severity information, on a weekly basis as a minimum.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 380 24.6.12 Environment The Engineer’s staff and all contractors will be made aware of the site environment conditions and constraints at the time of induction. Vista Environmental staff will be asked to audit site works on a periodic basis to identify issues of concern or non-conformance with site environmental policies and procedures. All contractors must be able to demonstrate compliance with the EHS Project Management Plan. The Plan will be incorporated into all tender documentation. 24.6.13 Schedule 24.6.13.1 Schedule Objectives and Scope The key objective of the PFS phase EPCM schedule is to provide a Class 3, Level 3 detail Schedule with an accuracy range of ±15%. Class of Schedule defines the degree of completeness required for schedule development, Class 5 being a low degree of completeness, and Class 1 being a high degree of completeness. Level of Schedule defines the degree of detail for communication, reporting, and execution, Level 1 being a low degree of detail and Level 5 being a high degree of detail. The scope included in the Schedule is that which is included in the EPCM contractor’s scope, as defined in the Technical Report. Consequently, Client Activities, Mine Development, Tailings Dam, Power plant detail, or Waste Water Treatment Plant are excluded from Schedule. 24.6.13.2 Schedule Assumptions For the Project, the specific schedule assumptions include: „ The Northern Territory wet season runs from ~1st December to ~17th April when heavy rains can impact construction activities at times, particularly civil and concrete works; „ No force majeure disruptions to scheduled work (IR or otherwise); „ Open access to all work fronts is available; „ Transportation to and from site (both air and land) is without delay; and „ The schedule has assumed that project approval will be given by Vista on or about January 1, 2021. Start up, as defined by handover after completion of commissioning is scheduled to early-mid-2023. 24.6.13.3 Critical Activities The Critical Path of the EPCM Schedule runs through the Vista approval process and the purchase packages and contracts for Area 3300 (Classification and Grinding) as follows: „ P001 Ball Mills Scope Development and Tender Period ......... 11 weeks „ P001 Ball Mills Manufacture and Delivery .............................. 63 weeks „ P001 Ball Mills SMP Construction ........................................... 24 weeks (Total) „ Area 3300 Verification and Commissioning ............................ 5 weeks The above critical activities determine a critical path of approximately 119 weeks duration after Project approval to proceed has been given.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 381 24.6.13.4 Significant Activities Major procurement packages with a lead time ex-works greater than 40 weeks are: Table 24-12: Supply Packages with Significant Lead Times Package Lead Time P001 – Ball Mills 55 weeks P002 – Primary Crusher 48 weeks P004 – HPGRs 52 weeks P012 – Agitators 60 weeks P024 – Mill Relining Machine 52 weeks P029 – Ore Sorting 45 weeks P030 – Secondary Grinding Mills 54 weeks 24.6.13.5 Commissioning Schedule The Commissioning Schedule has been broken into five specific activities in each area / sub area: 1) Construction Verification (CV) a) Occurs immediately after construction completion for each area (e.g. 3100, 3200, etc.) with each area CV start date independent of the others 2) Pre commissioning a) Occurs once CV is finished for each sub area b) 100,000t of ore available before pre-commissioning commences 3) Dry Commissioning (DC) a) Requires equipment power up so each of the five sub stations (one for crushing / stockpile, one for HPGRs, one for milling, Secondary Grinding and one for leach / CIP / gold room / air / water services) need to be completed prior to commencing DC. b) Should also occur in the order of: ⎯ Safety Systems (fire water / safety showers, etc.) ⎯ Process ancillary equipment (instrument air / gland water, etc.) ⎯ Process equipment substation groupings ⎯ Check Spares receipted into site store for equipment items in the area 4) Wet Commissioning (WC) a) The order for WC needs to be: ⎯ Safety systems (fire water / safety showers, etc.) ⎯ Environmental systems (storm water pond pumps, sump pumps, etc.) ⎯ Process ancillary equipment (instrument air / gland water, etc.) ⎯ Process area where both the current area and downstream area dry commissioning has been completed ⎯ Workforce training completed

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 382 5) Process Commissioning a) Will occur sequentially in the order of process flows, with the proviso that each area within a process zone terminated by a large storage buffer has been completed. Large storage buffers likely to create independent process commissioning zones include: ⎯ Crushed ore stockpile ⎯ Thickener ⎯ Leach / CIP Tanks 24.6.13.6 Schedule Interfaces The EPCM Schedule does not include detailed activities from contractors undertaking scopes of work outside the PFS scope such as the Tailings Dam, Waste Water Treatment Plant, Mine Development, and the Power Plant. The Construction schedule is currently based on best estimate for the logical sequence of activities as developed by the Feasibility Study contractor. Upon award of contracts during the EP phase, construction contractors will be required to each develop and provide their schedules which will form a Class 3 Level 4 detailed schedule. This schedule will only be baselined with the approval of Vista, EPCM contractor, and the Construction contractor. 24.6.13.7 Reporting The Engineer’s Project Manager will ensure that the Schedule is updated within 3 working days of the end of each calendar month such that progress against project milestones and activities can be clearly identified. The project schedule will also show the critical path(s) at each update such that possible improvements in project completion forecast may be made. Each month the EPCM contractor will provide the following to Vista and contractors: „ The whole schedule „ Critical Path/20 day or less Total Float view that will identify the critical path while also showing the activities with less than 20 days Total Float „ Mid-month short form status report covering expenditure and schedule compliance

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 383 Figure 24-6: EPCM Summary Schedule

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 384 25.0 INTERPRETATION AND CONCLUSIONS 25.1 Project Risks Significant risks and uncertainties that could reasonably affect the reliability or confidence in the Project outcome are provided in Table 25-1. The Project is an advanced-staged development project that has undergone engineering and permitting for a number of years. In order to manage cost and schedule risk, Vista retained GR Engineering Services of Perth, Australia to undertake a benchmarking study to assess the appropriateness of capital and operating cost estimates, construction and ramp-up schedules, owner's costs and key components of the Project (e.g., power supply). As such, the development risks that are within the control of Vista are considered low to moderate. Table 25-1: Project Risks Risk Description Probability Severity Gold Price The Project economics are sensitive to gold price. Sustained downward gold price trends could render the project uneconomic. Low-Medium High Foreign Exchange The Project capital and operating costs are sensitive to foreign exchange changes. A strengthen Australian dollar without an offsetting positive change in the gold price could render the Project uneconomic. Low-Medium High Political Setting Australia and the Northern Territory have historically been supportive of the extractive industries. Changes in legislation could have a negative impact on the project. Low Medium Jawoyn The JAAC is supportive of the Project. Changes in Vista’s relationship with JAAC could have social impacts on the Project. Low Low-Medium Permitting & Regulatory Approvals The Project has received both EIS and EPBC authorizations as described in Section 20. Low Medium Property Holdings Vista has secured the Mt Todd concession holdings as described in Section 4.0. Any change could have negative impacts to the Project. Low Low Infrastructure The Project relies on the use of existing infrastructure. The condition of which is well known and is functional. Significant deficiencies would result in increased capital expense. Low Low Understanding of Resource The Project viability relies upon historical drilling as well as recent drilling to develop and assess the resource model. New drill results could adversely affect the interpretation of parts of the deposit, with impacts to resources and production estimates. Low Low

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 385 Risk Description Probability Severity Power Plant Estimated Capital The proposed power plant utilizes industry standard equipment that is currently in use in Australia. Changes in cost could affect Project economics. Low Low-Medium Reagents & Consumables The process operating costs are sensitive to global changes in reagents and consumables pricing. Medium Medium Fuel The Project operating costs are sensitive to global changes in prices for diesel and natural gas. Medium Medium Mobile Equipment Capital Mobile equipment prices are an important part of the Project capital. Significant increases could impact the Project economics. Low Low-Medium Process Technology Extensive testing has been completed to identify the most suitable technology and equipment in the process are. The performance of the selected equipment could negatively impact Project economics. Low-Medium Medium Climatic Events Day to day mining operations could be significantly impacted by high precipitation events. Low Low-Medium Groundwater Day to day mining operations could be impacted by groundwater inflow. Low Low Water Treatment Heavy and sustained rains could result in water treatment in excess of capacity for short periods. Low-Medium Medium Existing TSF 1 Restarting of TSF 1 operations is an integral part of the Project plan. This facility has been idle for many years, delays could impact the schedule. Low Low-Medium Reclamation & Closure There is potential for reclamation activities to extend beyond the active planned closure period, and therefore generate greater sustaining costs. Additional risk lies should the closure design not perform as intended. Low Medium 25.2 Geology and Resources The Project is situated within the southeastern portion of the Early Proterozoic Pine Creek Geosyncline which is comprised of the Burrell Creek Formation, the Tollis Formation, and the Kombolgie Formation. Gold mineralization in this area is constrained to a single mineralization event and the deposits are classified as orogenic gold deposits in the subdivision of thermal aureole gold style. The Batman deposit has characteristics of an intrusion related gold system making it the primary resource. The Batman deposit is defined by approximately 7.4 million ounces (Moz) of gold within 278 Mt of measured and indicated resource at an average grade of 0.82 g-Au/t and a cutoff grade of 0.4 g-Au/t as provided in Table 14-1.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 386 In addition, opportunities for the Project resource may include: „ In addition to the mineral reserves at the Batman Deposit, the Company estimates measured and indicated resources of 1.7 million ounces gold (70.2 million tonnes at 0.77 g Au/t) and inferred resources of 1.4 million ounces gold (61.3 million tonnes at 0.72 g Au/t). A portion of the inferred resources are contained within the existing pit design and are currently included in the mine plan as waste material. Additional resources are predominantly at depth and lateral along strike. Potential to convert part of the mineral resources to reserves represents an opportunity to improve existing LOM economics and extend mine life. „ The Company also has known mineral resources at the Quigleys Deposit, which is close to the planned processing plant. The estimated grade of the Quigleys Deposit is higher than the estimated average grade of the Batman Deposit and could provide a source of higher-grade feed in the mid years of the Project when higher stripping is encountered and the average grade of feed to the plant is expected to decrease. Additional drilling and metallurgical testing are required to develop mine plans and ultimately convert part of the Quigleys resource to proven or probable reserves. „ Growth through exploration represents additional opportunity to add value at Mt Todd. Both the Batman Deposit and Quigleys Deposit remain open. In addition, Vista controls over 1,100 sq. km of contiguous exploration licenses at the southeast end of the Pine Creek Mining District. Various gold targets have been identified through early-stage, grass roots exploration programs along the Cullen-Australis and Batman-Driffield structural corridors, the latter of which is the host to the Batman Deposit. To-date, Vista's exploration efforts have primarily focused on the Batman Deposit. 25.3 Mineral Reserve and Mine Planning Pit designs were completed based on WhittleTM pit optimizations and are appropriate for a metal price of approximately US$1,000 per ounce Au. The Mt Todd proven and probable reserves have been defined using economics based on a gold price of US$1,250 per ounce and an elevated cutoff grade of 0.40 g-Au/t. The proven and probable reserves were used to create a production schedule for mining, and a positive cash-flow analysis has been done based on the production schedule by Tetra Tech. The reserves have reasonable economics with respect to the statement of reserves under NI 43-101 regulations. Mine production constraints were imposed to ensure that mining wasn’t overly aggressive with respect to the equipment anticipated for use at Mt Todd. The schedule has been produced using mill targets and stockpiling strategies to enhance the project economics. The constraints and limits are reasonable to support the project economics which are used to justify the statement of reserves. Pit designs use six-meter benches for mining. This corresponds to the resource model block heights, and the QP [Thomas L. Dyer, P.E.] believes this to be reasonable with respect to dilution and equipment anticipated to be used in mining. In areas where the material is consistently ore or waste so that dilution is not an issue, benches may be mined in 12-m heights.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 387 25.4 Mineral Processing The substantial quantity and quality of metallurgical test work data developed from Mt Todd drill core samples has led to the development of a robust energy efficient comminution circuit followed by a standard gold recovery process. Key conclusions drawn from the metallurgy studies are: „ Mt Todd (Batman) ore is among the hardest and most competent ore types processed for mineral recovery. The most energy efficient comminution circuit has been determined to be the sequence of primary crushing, closed circuit secondary crushing, and closed circuit HPGR tertiary crushing followed by ball milling. „ The ore is free-milling, is not preg-robbing, and is amenable to gold extraction by conventional cyanidation processes. „ The ore has relatively high specific cyanide consumption. This is largely due to the presence of sulfides, cyanide consuming copper, and destruction of residual cyanide. „ The use of sorting has helped to decrease operational costs and remove portions of the harder rock mined. The equipment selection criteria for the operation has received considerable interaction with specialist vendors to the point where there is a reasonably high degree of confidence in selected technology and process units at this preliminary feasibility study stage. The recommended flowsheet for FS consists of primary crushing, closed circuit secondary crushing, closed circuit tertiary crushing using HPGRs, ball milling, cyclone classification, pre-leach thickening, leach and adsorption, elution electrowinning and smelting, carbon regeneration, tailings detox and disposal to conventional tailings storage facility. 25.5 Infrastructure 25.5.1 Site Preparation Bulk earthworks are designed to minimize the import of fill materials. 25.5.2 Support Buildings „ Administration offices, gatehouse/security facilities, cribs/ablutions are planned to be transportable buildings. „ The process plant offices, workshop and warehouse are located inside the existing Flotation Building. „ Sample preparation and laboratory will have a purpose-built steel shed. 25.5.3 Access Roads Parking and Laydown The access road is based on the repaired existing road. 25.5.4 Heavy Lifts Heavy cranage is allowed for all lifts greater than 50 t.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 388 25.5.5 Bulk Transport All bulk transport will be weighed. 25.5.6 Communications Site-wide communication is based on a 50 m tall communication tower that will support eight (8) channels. 25.6 Project Services The economic model uses a natural gas price derived from east coast gas pricing. The Company believes that there may be a significant opportunity to achieve a lower gas price upon commitment to a long-term gas delivery contract. This belief is in part based on local expectations of significantly increased gas reserves in the Beetaloo Basin south of the Mt Todd project. The Company is also considering additional optimization of the power plant. 25.7 Environmental and Social Conclusions 25.7.1 Existing Body of Work A number of environmental studies have been conducted at the Project Site in support of development of Environmental Impact Statements and as required for environmental and operational permits. Studies conducted have investigated soils, climate and meteorology, geology, geochemistry, biological resources, cultural and anthropological sites, socio-economics, hydrogeology, and water quality. 25.7.2 Environmental Impact Study and Approvals The Environmental Impact Study (“EIS”) was submitted in June 2013. The NT Environmental Protection Authority provided its final assessment of the Project in June 2014. Notification of approval of the EIS was given September 2014. Vista has received all major environmental approvals to proceed with the Project. 25.7.3 Social or Community Impacts The Jawoyn people have strong involvement in the planning of the Project. Areas of aboriginal significance have been designated, and the mine plan has avoided development in these restricted works areas.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 389 25.8 Results of the Site-wide Water Balance Model Under the modeled conditions, the SWWB model results indicate that: „ The WTP rate of 500 m3/hr and PWP sizing for 6 days of storage appear adequate for the 50,000 tpd production process water requirements. „ The greatest amount of make-up water required from the RWD was quantified as 11,955 m3/day. RWD requirements were found to be the most dependent upon TSF decant volumes. „ The WRD retention pond (RP1) was typically observed to overtop less than 1% of the time during the 13-year simulation.[1] LGRP storage may be optimized. [1] A typical value is given. Separate model runs provide a range of overtopping events, due to the stochastic nature of the model.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 390 26.0 RECOMMENDATIONS The following recommendations are presented for consideration and were developed using best engineering judgement to estimate the costs of the respective recommendations. 26.1 Feasibility Study A FS is recommended to advance the Project to a place where any additional detailed information necessary provides support of capital and operating cost estimates which lead to a potential project development decision. The estimated budget for the FS is approximately US$2,500,000. 26.2 Resource and Exploration The Batman deposit potentially extends along strike both to the north and south. Step out drilling should be used to explore this. Additional deep infill drilling should be used to help define potential deep mineralization not detected by earlier drillholes. Infill drilling within and exploration drillholes along the trend of the Quigley deposit is recommended. Additional drilling exploring the exploration licenses, following up on geophysical and geochemical anomalies. The estimated budget for drilling within the mining licenses is US$500,000-1,000,000 and US$500,000- 1,000,000 for initial drilling on the exploration licenses. 26.3 Mining Risks and Opportunities 26.3.1 Opportunities Some refinement of dump designs for the chosen ultimate pit may help to reduce the overall footprint of the resulting dumps and therefore reduce closure costs. Current blasting patterns have been tightened up to reduce oversize. With experience, the blasting patterns can be optimized to reduce both drilling and blasting costs. 26.3.2 Risks Large stockpiles of low-grade ore are used for reasonably long periods of time. These stockpiles may oxidize during storage and the resulting recoveries from these stockpiles may be overstated due to the change of chemistry.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 391 26.4 Environmental Studies Additional studies will be needed to further assess environmental baseline conditions to support feasibility level design, permitting, and closure planning for the Project, including: „ Erosion analyses; „ Waste and cover material hydraulic properties characterization and analysis; „ Acid-base accounting on waste rock and tailings; „ Ongoing aquatic, benthic and wildlife studies; „ Comprehensive vegetation survey; „ Archaeological and historical assessments for all areas to be disturbed; „ Hydrogeologic investigations and site-wide hydrogeologic characterization; and „ Precipitation, stream flow, and watershed data. It is also recommended that further investigation be conducted to identify a source of low-permeability material suitable for use in closure covers located closer to or within the project site boundaries. The estimated budget for this work is US$350,000. 26.5 Site-wide Water Balance Recommended model improvements include: „ The site-wide water balance model is dependent upon the TSF water balance model, which provides decant water to the process facility, and the vadose and seepage models, which characterize seepage through the various rock piles on site (WRD, LGOS, and HLP). As such, refinement of the TSF water balance model including completion of these models to the greatest detail practicable affects the overall quality of the site-wide water balance model results. „ Incorporate results of future Batman Pit potential groundwater inflow investigation. „ Optimize management of Batman Pit dewatering effluent and other contact water. This water may be of sufficient quality to be used as make-up water to the process circuit offsetting the water coming from the RWD. This water would also reduce the amount of water ultimately requiring treatment. „ In this iteration of the site-wide water balance model, the entirety of the WTP effluent is being used as dust suppression around the mine site during the dry season. Further investigation of other uses of the WTP effluent should be conducted. „ Further investigation of the adequacy of RP1 storage capacity is recommended, particularly within the early stages of the LoM when a larger fraction of the catchment reports to this pond. „ Incorporate RWD stage-storage relationship and catchment area into the site-wide water balance model such that it may be modeled as a reservoir, as opposed to an infinite source. „ Inclusion of process, fire, potable and raw water tanks. At present, only the dust suppression tank is modeled. The tanks above are currently modeled as drawing water directly from the RWD, rather than demands on discrete tanks. „ Review and update dust suppression requirements. „ Incorporate evolving Batman Pit shell geometry to more accurately model that facility.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 392 The estimated budget for this work is US$200,000. 26.6 Groundwater Hydrology and Mine Dewatering The following work is recommended with respect to groundwater hydrology and mine dewatering: „ Additional hydrogeologic study should be completed in the vicinity of the Batman Pit to provide more detailed information on which to base calibration of the regional groundwater flow model and subsequent prediction of groundwater inflows to the pit and post-mining recovery of the groundwater system. The study should include permeability testing by packer test methods in three to five selected borings within or immediately adjacent to the pit and drilled to the proposed ultimate depth of the pit. The packer testing in those borings should be conducted over relatively short (10 m to 30 m) intervals, beginning at the water table and extending to the total depth of the borings. This testing could be combined with exploration drilling by performing the testing in exploration core holes. The study should also include measurement of depth to water in any accessible existing borings or core holes within or immediately adjacent to the pit. „ Calibration of the regional groundwater flow model should be completed with the additional data, and the calibrated model should be used to refine the estimates of groundwater inflow to the pit and predictions of the hydrogeologic effects of pit dewatering. „ The post-mining version of the groundwater flow model should be updated with the calibrated model used as its basis. Output from the post-mining model should be incorporated into any geochemical modeling of post-mining pit lake formation and geochemistry. The estimated budget for this work is US$200,000. 26.7 Process Plant Geotechnical Investigation Recommendations For the DFS future geotechnical work is suggested in the following areas, and is estimated at US$150,000. 26.7.1 Crushing/Screening/Grinding/HPGR/Sorting All large vibrating structures should be founded in rock rather than on fill to reduce dynamic effects. An accurate rock level is required to confirm foundation design and accurately estimate required concrete quantities and rock excavation. The existing structure concrete slabs are located directly over the new mill location, so it is recommended that additional new test pits around all four sides be undertaken to allow interpolation. 26.7.2 Thickener/Leach/CIP There are large tanks to be constructed in this area, with high foundation bearing pressure. Variation in rock level will impact the potential for differential settlement which needs to be considered. It is recommended at least four additional test pits to evaluate variance in rock levels in north-south and east-west directions.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 393 26.7.3 Stockpile & Reclaim There is no test pit data near this area (the nearest test pit is more than 200m away). Steeply sloping ground surface exists (in excess of 5 m variation in ground level across the reclaim tunnel) so there may be considerable variation in rock levels which will affect potential settlement due to stockpile surcharge and required excavation for the concrete vault and tunnel. A new borehole is recommended on the high side (determine whether this high side bench is fill material, and therefore whether rock would be encountered within the limits of an excavator for a test pit) and a new test pit on low side, to determine rock levels. 26.8 Tailings Facility Design The following studies and investigations are recommended to support TSF design for future phases of the project: 26.8.1 TSF Construction Schedule The TSF staging and construction schedule must be optimized during the feasibility study phase of the project to minimize mobilization costs. 26.8.2 Investigation of TSF1 Drainage Features The condition of the existing toe drains, underdrains, and decant towers must be investigated to confirm their condition prior to re-commissioning of TSF1. 26.8.3 Geotechnical Investigation and Assessment Additional geotechnical investigations are recommended, including drilling, sampling, and laboratory testing to characterize the geotechnical properties of the surface and subsurface materials. The geotechnical drilling program should include Standard Penetration Testing (SPT) and/or Cone Penetration Testing (CPT). CPT investigation within the existing TSF1 tailings is recommended to support assessment of the raise foundation strength and liquefaction analysis. A program of laboratory geotechnical testing of a sample of representative future tailings is recommended as part of future design work, including index testing (particle size, plasticity, specific gravity), compaction testing, and advanced testing to assess consolidation, strength and permeability after compaction, and unsaturated soil characteristics. 26.8.4 Waste Rock Testing Additional laboratory testing of the waste rock is recommended, including, but not limited to, proctor compaction, hydraulic conductivity, and shear strength testing. No testing of the run-of-mine waste was conducted for this study, and a representative range of strength parameters would improve predictions of behavior related to slope stability. 26.8.5 Consolidation/Seepage Modeling The seepage and stability analyses discussed in this report were based on laboratory tests conducted on the in-situ tailings. Large scale consolidation tests should be conducted on bench scale samples of the proposed process tailings to determine hydraulic conductivities as a function of effective stress. The seepage and stability analyses must be updated based on these representative material properties. Additionally, seepage

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 394 and stability analyses must be conducted assuming that the underdrain system is plugged to assess its influence on the stability of future vertical expansions. 26.8.6 Water Balance A TSF water balance analysis which includes the return water ponds must be conducted to predict the volume of recycle water available for process operations. The results of the water balance analysis will also be used to size the return water system which includes the existing decant structures and an additional barge pump. 26.8.7 TSF Consequence Classification A formal dam classification assessment is recommended as part of future design work. Under ANCOLD guidelines, the Consequence Category is determined for a potential dam failure and environmental spill. The classification should include a failure modes assessment, a dam break and inundation study, and consideration of the potential for impacts to business, social and environment, and the potential for loss of life. The resulting Consequence Category for the tailings storages will be used to identify parameters for advancing the design such as the design storm event and the design seismic event. 26.9 Process Operating Costs Two major items incurring operating costs are grinding media and reagents. Together these items make up 61% of the plant consumables operating costs. The FS should investigate options for reducing the consumption rate and the unit costs for these consumables. This work is included in the estimated budget for the FS. 26.10 Geochemical Analyses Geochemical characterization will be updated to reflect the designations of Potentially Acid Forming, Potentially Acid Forming-Low Capacity, Non-Acid Forming, Acid Consuming and Uncertain in accordance with DITR (2007) guidelines. Additional geochemical testing is recommended on the sorter reject material. This work is included in the estimated budget for the FS. 26.11 Process Parameter Optimization The on-going testwork is directed at optimization of process parameters which is expected to result in both capital and operating cost reductions as detailed in this Technical Report.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 395 27.0 REFERENCES ALS, 2013. CIL Extractive Testwork conduct upon heap leach (X2) and Drill hole (X2) composites from the Mt Todd Gold Project, April 2013. ALS Ammtec, May 2012. Metallurgical Testwork Report No. A13575. ANZECC & ARMCANZ, 2000, Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Environment and Conservation Council (ANZECC) & Agriculture and Resource Management Council of Australia and New Zealand (ARMCANZ) Ausenco, August 2009. JKSimMet Circuit Simulations for the 11 mt Vista Gold Mt Todd Plant. Australian Government, Standing Council on Environment and Water and the National Health and Medical Research Council, 2011. National Water Quality Management Strategy - Australian Drinking Water Guidelines 6 (2011) – Version 3.4 Updated October 2017. Barkley, Ross, March 24, 2016, Review of Geotechnical Pit Slope Design for the Project, Call & Nicholas, Inc. internal memorandum. BKK, 1996. Pegasus Gold Australia Pty Ltd, Mt Todd Gold Mine, Phase 2 Development, Environmental Management Plan. Prepared by Bateman Kinhill Kilborn Joint Venture for Pegasus Gold. Bolger, C., and Glasscock, M., March 2000. Batman Resource Estimate General Gold Operations Pty. Ltd. Bolger, Chris, June 18, 1999. Internal Memorandum to Mackenzie, W. Subject: Grade Control – Believable Reconciliations or Not?, General Gold Operations Pty. Ltd. Bureau of Meteorology (BOM), 2017. Website accessed on April 13, 2017: http://www.bom.gov.au/climate/data/index.shtml, station number 14062 (Edith Falls Ridge). Chadwick T&T Pty Ltd, February 2009. Mt Todd Mine, Northern Territory Environmental Assessment. Prepared by Chadwick T&T Pty Ltd for Vista Gold Corp. CIM, 2014. Canadian Institute of Mining, Metallurgy and Petroleum. Standards on Mineral Resources and Mineral Reserves: Definitions and Guidelines, May 10, 2014. Dames & Moore, 1997. Mt Todd Dewatering Investigation Batman Pit. 9 October. Farrelly, C.T., February 1990. Check Assay Statistical Analysis of the Mt Todd Batman Deposit, N.T., BHP Resources Pty. Ltd. Internal Document. Francois-Bongarcon, D., August 20, 1995. Memorandum to Ormsby, Warren Ref: Draft Report - Site Visit, Mineral Resources Development Property Evaluators, Developers, and Consulting Engineers. GE Energy Aero Division, January 2009. Position Paper #50 - LM Gas Turbine Load Accept Guidelines. General Gold Operations Pty Ltd. 2000. Monthly Report for March 2000. General Gold Resources N.L., November 19, 1998. Review of the Resource Model: Mt Todd: Batman Deposit, Doc. Ref.: Mt Todd.2904.doc. GHD, November 2018. Appendix N – Flora and Fauna Management Plan, Mt Todd Project Area.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 396 GHD, June 2013. Environmental Impact Statement for the Mt Todd Gold Project. Gibbs, D.R., Horton, J., August 1990. Analysis of Bias between Drilling Techniques and Drill hole Orientations Used at Batman, Mt Todd, NT, Using The ‘Preferred’ Gold Assay Database, Report No. 08.5116. Gibbs, D.R., Horton, J., Pantalone, D., June 1990. Preliminary Analysis of Bias between Drilling Techniques Used at the Batman Deposit, N.T. Using the Original Gold Assay Database, Report No. 08.4449. Gibbs, Duncan, July, 1990. Corrections to the Batman Assay Database and the Impact of Preferred and Bias Corrections, Report No. 08.5117. Golder Associates, 2011. Mt Todd Gold Project: Batman Pit Slope Design Guidance in Support of the Definitive Feasibility Study, September 13, 2011. Gustavson Associates, LLC, December 2006. Preliminary Economic Assessment, Mt Todd Gold Project, NT, Australia. Gustavson Associates, LLC, December 29, 2006. Preliminary Economic Assessment – Mt Todd Gold Project – Northern Territory, Australia (NI 43-101 Report) Gustavson Associates, LLC, January 2008. Preliminary Assessment Awak Mas Gold Project. Hein, K.A.A., 2003. The Batman and Quigleys gold deposits of the Mt Todd (Yimuyn Manjerr) Mine, Australia: Structural, petrographic and mineralogical investigations of coeval quartz sulphide vein and lode/stockwork systems. Ore Geology Reviews 23(1-2), July 2003. Hein, K.A.A., Zaw, K. and Mernagh, T.P. (2006) Linking mineral and fluid inclusion paragenetic studies: The Batman deposit, Mt Todd (Yimuyn Manjerr) goldfield, Australia. Ore Geology Reviews, 28, 180-200.JK Tech. Pty. Ltd, August 2009. Comminution Test Report on Five Samples from Mt Todd Mine. KCA, May 2010. Mt Todd Project Report of Tailings Characterization Test Work. Kenny, K.J., July 1992. Mt Todd Project, Check Assay Results, May 1992 Drilling Programme, Report No. G57.92. Kenny, K.J., Gibbs, D, Wegmann, D, Fuccenecco, F., and Hungerford, N., March 30, 1990. The Geology and Exploration of the Batman Deposit and Immediate Vicinity, Report No. 08.4447. Khosrowshahi, S., Collings, P. and Shaw, W., August 1992. Geological 3D Modeling and Geostatistical Resource Estimation, Batman Deposit, NT for Zapopan NL, Mining & Resource Technology Pty. Ltd. Khosrowshahi, S., Collings, P., and Shaw, W., February 1991. Geostatistical Modeling and Resource Estimation, Batman Deposit, NT. for the Mt Todd Joint Venture. MacDonald, Craig, June 1997. Quigleys Gold Project, Statistics, Geostatistics and Resource Estimation, Snowden Associates Pty. Ltd. Mine Development Associates, Dec.22, 2011, Internal Memo: Mt Todd, check of assay data base (DRAFT)

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 397 Mineral Resources Development Property Evaluators, Developers, and Consulting Geologists and Engineers, September 1995. Zapopan NL Sampling and Reconciliation Study of the Mount Todd Gold Mine. Minproc Engineers, February 1989. Billiton Australia, Mt Todd Mining Feasibility Study, Stage 1 Report – Resource Development, Minproc Engineers Pty. Ltd. MWH, December 2006. Mt Todd Environmental Management Services TSF Scoping Study. MWH Australia Pty Ltd, March 2008. Mt Todd Environmental Management Services – Report 1: Environmental Assessment. MWH Australia Pty Ltd, March 2008. Mt Todd Environmental Management Services – Report 2: Water Management. MWH Australia Pty Ltd, March 2008. Mt Todd Environmental Management Services – Mt Todd Conceptual Closure Plan and Cost Estimate. MWH Australia Pty Ltd, March 2008. Mt Todd Environmental Management Services – TSF Scoping Study. National Geoscience Mapping Accord, Katherine (NT), Sheet SD 53-9, Second Edition, 1994. National Health and Medical Research Council, 2011. National Water Quality Management Strategy – Australian Drinking Water Guidelines 6. National Renewable Energy Laboratory (NREL) and Gas Research Institute (GRI), 2013. Gas Fired Distributed Energy Resource Technology Characterizations, November 2013. Ormsby, Warren, July 25, 1996. Mt Todd Mine Geology, Overview, and Recommendations for 1997. Pells Sullivan Meynink Pty Ltd, 2000. Mt Todd Gold Mine, Batman Pit, Geotechnical Review. February. Pincock Allen & Holt, December 29, 1995. Diligence Review of Pegasus Gold’s Mt Todd Operation and Phase II Expansion Feasibility Study, PAH Project No. 9127.00. Pocock Industrial Inc., October 2009. Flocculant Screening, Gravity Sedimentation, Pulp Rheology and Vacuum Filtration Studies for Vista Gold Mt Todd Project. Resource Development, Inc., May 19, 2006. Metallurgical Review of Mt Todd Project: Progress Report No. 1. Resource Development, Inc., December 15, 2006. Capital and Operating Costs Conceptual Process Flowsheet Treating 10.65 MM Tonnes per Year for Mt Todd Project, Australia. Resource Development, Inc., July 2009. Preliminary Metallurgical Testing of Mt Todd Ore: Progress Report No. 2. RDi, July 2009. Metallurgical Testing of Mt Todd Samples. Resource Development, Inc., May 3, 2018. Mt Todd Gold Project Metallurgical Test Report, Resource Development Inc. Resource Development, Inc., (To be published). 2018-19 Mt Todd Metallurgical Test Program in Support of Fine Grinding, Resource Development Inc.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 398 Rockwater, 1994. Bore Water Supply Expansion Programme Bore Completion Report, Mt Todd Gold Mine. Rockwater Proprietary Ltd., 1994. Bore Water Supply Expansion Programme, Bore Completion Report, Mt Todd Gold Mine, prepared for Zapopan NL, August. Rozelle, John W. with Gustavson Associates, LLC, June 2006. NI 43-101 Technical Report on the Mt Todd Gold Project, NT, Australia. Samuel Engineering, October 2012. Mt Todd Heap Leach Pad Scoping Study. Schwann, P., November 1995. The Geology and Grade Control at Mt Todd Gold Mine in the NT, Peter Schwann & Associates. Snowden, D.V., September 1990. Mount Todd Joint Venture, Statistical Analysis, and Resource Estimate for the Batman Orebody. Soil & Rock Engineering PTY LTD, April 1993. Mt Todd Heap Leach Project, Supplementary Geotechnical Investigations. Soil & Rock Engineering PTY LTD, December 1992. Mt Todd Heap Leach Project, Geotechnical Investigation. SRK Consulting, internal file. NI 43-101 Technical Report Mt Todd Project, NT, Australia. Tetra Tech, March 2008. NI 43-191 Technical Report Resource Update Mt Todd Gold Project, NT, Australia. Tetra Tech, May 2008. NI 43-191 Technical Report Resource Update Mt Todd Gold Project, NT, Australia. Tetra Tech Inc., May 15, 2008. Mt Todd Gold Project, Resource Update Northern Territory, Australia. Tetra Tech, February 2009. NI 43-191 Technical Report Resource Update Mt Todd Gold Project, NT, Australia. Tetra Tech Inc., February 27, 2009. Mt Todd Gold Project, Resource Update Northern Territory, Australia. Tetra Tech, June 2009. Updated Preliminary Economic Assessment Report, Mt Todd Gold Project. Tetra Tech, October 2010. Mt Todd Gold Project Preliminary Feasibility Study, Northern Territory, Australia. Tetra Tech, January 2011. 10.65 MTPY PFS NI 43-101 Technical Report Mt Todd Gold Project. Tetra Tech, October 2011. NI 43-191 Technical Report Resource Update Mt Todd Gold Project, NT, Australia. Tetra Tech, April 2012. Amended and Restated NI 43-101 Technical Resource update Mt Todd Gold Project Northern Territory, Australia. Tetra Tech, June 2012. Technical Memorandum: Waste Rock Dump Design and Drainage Evaluation for Mt Todd Project.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 399 Tetra Tech, October 2012. NI 43-101 Technical Report Resource Update Mt Todd Gold Project, Northern Territory, Australia. Tetra Tech, February 2013. Foundation Recommendations: Mt Todd Gold Project Feasibility Study. Tetra Tech, May 2013. Draft Final Report: Geochemistry Program for Mt Todd Gold Project. Tetra Tech, 2014. Amended and Restated NI 43-101 Technical Report – Mt Todd Gold Project, 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia. Effective date: May 29, 2013; Issue Date: June 28, 2013; Amended & Restated: July 7, 2014. Tetra Tech, 2018. NI 43-101 Technical Report – Mt Todd Gold Project, 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia. Effective date: January 24, 2018; Issue Date: March 2, 2018. Vista Gold Australia Pty Ltd, 2016. Mining Management Plan 2016, Mount Todd Gold Project. Wegeman, D., June 1990. Sampling Procedures and Controls Associated with Drilling in the Mt Todd J.V., Report No. 08.4446B. Wegeman, D. and Johnson, J. 1991. Mt Todd Joint Venture, Analytical and Sample Preparation Control Procedures Within the Mt Todd Joint Venture, Report No. 08.5360. The Winters Company, December 1997. Pegasus Gold Australia Pty. Ltd. Mt Todd Mine Review, Draft Document.

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 400 28.0 CERTIFICATE OF QUALIFIED PERSON 28.1 Qualifications of Consultants The Consultants preparing this Technical Report are specialists in the fields of geology, exploration, mineral resource and mineral reserve estimation and classification, underground mining, geotechnical, environmental, permitting, metallurgical testing, mineral processing, processing design, capital and operating cost estimation, and mineral economics. None of the Consultants or any associates employed in the preparation of this report has any beneficial interest in Vista. The Consultants are not insiders, associates, or affiliates of Vista. The results of this Technical Report are not dependent upon any prior agreements concerning the conclusions to be reached, nor are there any undisclosed understandings concerning any future business dealings between Vista and the Consultants. The Consultants are being paid a fee for their work in accordance with normal professional consulting practice. The following individuals, by virtue of their education, experience and professional association, are considered QPs as defined in the NI 43-101 standard, for this report, and are members in good standing of appropriate professional institutions. This Technical Report was prepared by the following QPs, Certificates and consents of which are contained herein: Name Title, Company Responsible for Sections Rex Clair Bryan, Ph.D., SME RM Principal Geostatistician Tetra Tech, Inc. Sections 1.4, 1.5, 1.15.2, 6, 6.1, 6.2, 6.3, 6.4, 7, 8, 9, 10, 11, 12, 14, 25.2, and 26.2 Anthony Clark, P.E., P.Eng Senior Mechanical Engineer POWER Engineers, Inc. Sections 18.8, 21.1.3, and 21.2.4 Thomas L. Dyer, P.E., SME RM Mining Engineer Mine Development Associates Sections 1.6, 1.7, 1.15.3, 15, 15.1, 15.2, 15.3, 15.4, 15.5, 16, 21.1.1, 21.2.1, 25.3, and 26.3 Chris Johns, M.Sc., P.Eng Geological Engineer Tetra Tech, Inc. Sections 1.15.9, 1.15.10, 18.2.4, 21.1.8, 21.2.6, 24.1, 26.7 and 26.8 Deepak Malhotra, Ph.D., SME RM Principal Metallurgist Pro Solv, LLC Sections 1.6.1, 1.8, 1.9, 1.15.4, 1.15.11, 6.5, 6.6, 13, 15.6, 17, 25.4, 26.9, and 26.11 April Hussey, P.E. Environmental Engineer Tetra Tech, Inc. Sections 1.15.7, 20.5, 21.1.5, 24.2.1, 25.8 and 26.5 Jessica I. Monasterio, P.E. Professional Engineer JDS Energy & Mining, Inc. Sections 1.11, 1.13, 1.14, 19, 21, 21.1, 21.2, and 22 Zvonimir Ponos, BE, MIEAust, CPeng, NER Senior Principal Engineer Coffey Services Australia Pty Ltd (trading as Tetra Tech Proteus) Sections 1.10, 1.15.5, 18.1, 18.2, 18.2.1, 18.2.2, 18.2.3, 18.2.5, 18.2.6, 18.3, 18.4, 18.5, 18.6, 18.7, 21.1.2, 21.2.3, 21.2.7, 24.6, 25.5, and 25.6 David M. Richers, PhD SME RM, CPG Geochemical Consultant, NEXUS Geos LLC Section 1.15.12, 24.3 and 26.10

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 401 Name Title, Company Responsible for Sections Vicki J. Scharnhorst, P.E., LEED AP Principal Tetra Tech, Inc. Sections 1.1, 1.2, 1.3, 1.12, 1.15.1, 1.15.6, 2, 3, 4, 5, 18, 20.1, 20.2, 20.3, 20.4, 21.1.6, 21.1.7, 21.2.5, 23, 24, 24.2, 24.2.2, 24.4, 25.1, 25.7, 26, 26.1, and 26.4 Keith Thompson, CPG, member AIPG Professional Geologist Tetra Tech, Inc. Sections 1.15.8, 21.1.4, 21.2.2, 24.5, 26.6 28.2 Table of Responsibility QPs are responsible for all subsections listed beneath headings unless subsections are detailed below. Section No Section Name QP 1 SUMMARY (No Intro) N/A 1.1 Introduction Scharnhorst, Vicki 1.2 Location Scharnhorst, Vicki 1.3 Property Description Scharnhorst, Vicki 1.4 Geology and Mineralization Bryan, Rex 1.5 Mineral Resource Estimate Bryan, Rex 1.6 Mineral Reserve Estimates Dyer, Tom 1.6.1 Heap Leach Reserve Estimate Malhotra, Deepak 1.7 Mining Methods Dyer, Tom 1.8 Metallurgy Malhotra, Deepak 1.9 Mineral Processing Malhotra, Deepak 1.10 Project Infrastructure Ponos, Zvonimir 1.11 Market Studies and Contracts Monasterio, Jessica 1.12 Social and Environmental Aspects Scharnhorst, Vicki 1.13 Capital and Cost Estimates Monasterio, Jessica 1.14 Financial Analysis Monasterio, Jessica 1.15 Conclusions and Recommendations (No Intro) N/A 1.15.1 Feasibility Study Scharnhorst, Vicki 1.15.2 Geology and Resources Bryan, Rex 1.15.3 Mineral Reserve and Mine Planning Dyer, Tom 1.15.4 Mineral Processing Malhotra, Deepak 1.15.5 Infrastructure Ponos, Zvonimir 1.15.6 Environmental and Social Impacts Scharnhorst, Vicki 1.15.7 Results of the Site-wide Water Balance Model Hussey, April 1.15.8 Groundwater Hydrology and Mine Dewatering Thompson, Keith

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 402 Section No Section Name QP 1.15.9 Process Plant Geotechnical Investigation Johns, Chris 1.15.10 TSF Design Johns, Chris 1.15.11 Process Malhotra, Deepak 1.15.12 Geochemical Analyses Richers, Dave 2 INTRODUCTION Scharnhorst, Vicki 3 RELIANCE ON OTHER EXPERTS Scharnhorst, Vicki 4 PROPERTY DESCRIPTION AND LOCATION Scharnhorst, Vicki 5 ACCESSIBILITY, CLIMATE, LOCAL RESOURCES, INFRASTRUCTURE AND PHYSIOGRAPHY Scharnhorst, Vicki 6 HISTORY Bryan, Rex 6.1 History of Previous Exploration Bryan, Rex 6.2 Historic Drilling Bryan, Rex 6.3 Historic Sampling Method and Approach Bryan, Rex 6.4 Historic Sample Preparation, Analysis, and Security Bryan, Rex 6.5 Historic Process Description Malhotra, Deepak 6.6 Technical Problems with Historical Process Flowsheet Malhotra, Deepak 7 GEOLOGICAL SETTING AND MINERALIZATION Bryan, Rex 8 DEPOSIT TYPES Bryan, Rex 9 EXPLORATION Bryan, Rex 10 DRILLING Bryan, Rex 11 SAMPLE PREPARATION, ANALYSES AND SECURITY Bryan, Rex 12 DATA VERIFICATION Bryan, Rex 13 MINERAL PROCESSING AND METALLURGICAL TESTING Malhotra, Deepak 14 MINERAL RESOURCE ESTIMATES Bryan, Rex 15 MINERAL RESERVES Dyer, Tom 15.1 Pit Optimization Dyer, Tom 15.2 Pit Designs Dyer, Tom 15.3 Cutoff Grade Dyer, Tom 15.4 Dilution Dyer, Tom 15.5 Reserves and Resources Dyer, Tom 15.6 Heap Leach Reserve Estimate Malhotra, Deepak 16 MINING METHODS Dyer, Tom 17 RECOVERY METHODS Malhotra, Deepak 18 PROJECT INFRASTRUCTURE Scharnhorst, Vicki 18.1 Facility 2000 – Mine Ponos, Zvonimir 18.2 Facility 4000 – Project Services Ponos, Zvonimir

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 403 Section No Section Name QP 18.2.1 Area 4100 – Water Supply Ponos, Zvonimir 18.2.2 Area 4200 – Power Supply Ponos, Zvonimir 18.2.3 Area 4300 – Communications Ponos, Zvonimir 18.2.4 Area 4400 – Tailings Dam Johns, Chris 18.2.5 Area 4500 – Waste Disposal Ponos, Zvonimir 18.2.6 Area 4600 – Plant Mobile Equipment Ponos, Zvonimir 18.3 Facility 5000 – Project Infrastructure Ponos, Zvonimir 18.4 Facility 6000 – Permanent Accommodation Ponos, Zvonimir 18.5 Facility 7000 – Site Establishment and Early Works Ponos, Zvonimir 18.6 Facility 8000 – Management, Engineering, EPCM Services Ponos, Zvonimir 18.7 Facility 9000 – Preproduction Costs Ponos, Zvonimir 18.8 Electric Power Plant Clark, Anthony 19 MARKET STUDIES AND CONTRACTS Monasterio, Jessica 20 ENVIRONMENTAL STUDIES, PERMITTING, AND SOCIAL OR COMMUNITY IMPACT 20.1 Environmental Studies Scharnhorst, Vicki 20.2 Waste and Tailings Disposal, Site Monitoring and Water Management Scharnhorst, Vicki 20.3 Permitting and Authorizations Scharnhorst, Vicki 20.4 Social or Community Requirements Scharnhorst, Vicki 20.5 Mine Reclamation and Closure Hussey, April 21 CAPITAL AND OPERATING COSTS Monasterio, Jessica 21.1 Capital Cost Monasterio, Jessica 21.1.1 Mining (MDA) Dyer, Tom 21.1.2 CIP Process and Infrastructure (Proteus) Ponos, Zvonimir 21.1.3 Power Plant (POWER Engineers) Clark, Anthony 21.1.4 Mine Dewatering (Tetra Tech) Thompson, Keith 21.1.5 Reclamation and Closure (Tetra Tech) Hussey, April 21.1.6 Water Treatment Plant (Tetra Tech) Scharnhorst, Vicki 21.1.7 Raw Water Dam (Tetra Tech) Scharnhorst, Vicki 21.1.8 Tailings Storage Facilities (Tetra Tech) Johns, Chris 21.2 Operating Costs Monasterio, Jessica 21.2.1 Mining (MDA) Dyer, Tom 21.2.2 Mine Dewatering (Tetra Tech) Thompson, Keith 21.2.3 CIP Process and G&A (Proteus) Ponos, Zvonimir 21.2.4 Power Plant (POWER Engineers) Clark, Anthony 21.2.5 Water Treatment Plant (Tetra Tech) Scharnhorst, Vicki

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 404 Section No Section Name QP 21.2.6 Tailings Storage Facilities (Tetra Tech) Johns, Chris 21.2.7 General & Administrative Ponos, Zvonimir 22 ECONOMIC ANALYSIS Monasterio, Jessica 23 ADJACENT PROPERTIES Scharnhorst, Vicki 24 OTHER RELEVANT DATA AND INFORMATION Scharnhorst, Vicki 24.1 Process Plant Geotechnical Johns, Chris 24.2 Water Management Scharnhorst, Vicki 24.2.1 Site-wide Water Balance Hussey, April 24.2.2 Wet Infrastructure Scharnhorst, Vicki 24.2.2.1 Water Treatment Plant Scharnhorst, Vicki 24.2.2.2 Water Quality Standards for Waste Water Discharge Scharnhorst, Vicki 24.2.2.3 Raw Water Reservoir and Pipeline Scharnhorst, Vicki 24.2.2.4 Potable Water Scharnhorst, Vicki 24.2.2.5 Sanitary Sewer System Scharnhorst, Vicki 24.3 Geochemistry Richers, Dave 24.4 Surface Water Hydrology Scharnhorst, Vicki 24.5 Regional Groundwater Model and Mine Dewatering Thompson, Keith 24.6 Project Implementation Ponos, Zvonimir 25 INTERPRETATION AND CONCLUSIONS (No Intro) N/A 25.1 Project Risks Scharnhorst, Vicki 25.2 Geology and Resources Bryan, Rex 25.3 Mineral Reserve and Mine Planning Dyer, Tom 25.4 Mineral Processing Malhotra, Deepak 25.5 Infrastructure Ponos, Zvonimir 25.6 Project Services Ponos, Zvonimir 25.7 Environmental and Social Conclusions Scharnhorst, Vicki 25.8 Results of the Site-wide Water Balance Model Hussey, April 26 RECOMMENDATIONS Scharnhorst, Vicki 26.1 Feasibility Study Scharnhorst, Vicki 26.2 Resource and Exploration Bryan, Rex 26.3 Mining Risks and Opportunities Dyer, Tom 26.4 Environmental Studies Scharnhorst, Vicki 26.5 Site-wide Water Balance Hussey, April 26.6 Groundwater Hydrology and Mine Dewatering Thompson, Keith 26.7 Process Plant Geotechnical Investigation Recommendations Johns, Chris 26.8 Tailings Facility Design Johns, Chris

NI 43-101 Technical Report Vista Gold Corp. 50,000 tpd Preliminary Feasibility Study – Northern Territory, Australia Mt Todd Gold Project Tetra Tech October 2019 405 Section No Section Name QP 26.9 Process Operating Costs Malhotra, Deepak 26.10 Geochemical Analyses Richers, Dave 26.11 Process Parameter Optimization Malhotra, Deepak 27 REFERENCES N/A 28 CERTIFICATE OF QUALIFIED PERSON N/A 28.1 Qualifications of Consultants N/A 28.2 Table of Responsibility N/A

CERTIFICATE OF QUALIFIED PERSON Rex Clair Bryan, Ph.D., SME RM Principal Geostatistician Tetra Tech, Inc. 350 Indiana Street, Suite 500 Golden, Colorado 80401 Telephone: (303) 217-5700 Facsimile: (303) 217-5705 Email: Rex.Bryan@tetratech.com This certificate applies to the report entitled: “NI 43-101 Technical Report – Mt Todd Gold Project – 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia” (“Technical Report”), effective date September 10, 2019, issued on October 7, 2019, and as amended September 22, 2020. I, Rex Clair Bryan, Ph.D., do hereby certify that: 1) I am a Senior Geostatistician with Tetra Tech, Inc. with a business address at 350 Indiana Street, Suite 500, Golden, Colorado USA, 80401. 2) I graduated with a Ph.D. degree in 1980 from the Colorado School of Mines, Golden Colorado, USA. In addition, I graduated with a degree MSc. In Geology in 1976 from the Brown University, Providence, Rhode Island, USA. I have worked as a Geostatistician for a total of 39 years since my graduation. My relevant experience is in the areas of resources and reserve reporting. I am a Competent/Qualified Person , with the Society of Mining Engineers in Colorado, USA (SME Registered Member #411340). 3) I have read the definition of “qualified person” set out in National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”) and certify that by reason of my education, affiliation with a professional association (as defined in NI 43-101) and past relevant work experience, I fulfill the requirements to be a “qualified person” within the meaning of NI 43-101. 4) I have personally visited and inspected the property which is the subject of the Technical Report on June 28th and June 29th, 2017 for two days. In addition, I have visited and inspected the property September 12th, 2011 to September 14th, 2011 and February 6th, 2013 to February 8th, 2013. 5) I am responsible for Sections 1.4, 1.5, 1.15.2, 6, 6.1, 6.2, 6.3, 6.4, 7, 8, 9, 10, 11, 12, 14, 25.2, and 26.2 of the Technical Report. 6) I am independent of the issuer, Vista Gold Corp., according to Section 1.5 of NI 43-101. 7) I have had prior involvement with the property that is the subject of the Technical Report. My involvement has consisted of acting as an qualified person for the NI 43-101 Technical Report – Mt Todd Gold Project, 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia, issue date March 2, 2018; the NI 43-101 Technical Report – Mt Todd Gold Project 50,000 tpd Preliminary Feasibility Study, amended and restated date July 7, 2014; and the Amended and Restated NI 43-101 Technical Report Resource Update Mt Todd Gold Project, Issue Date of Amendment and Restatement: April 11, 2012. 8) I have read NI 43-101, Form 43-101F1 – Technical Report, 43-101CP – Standards of Disclosure for Mineral Projects, and the Technical Report has been prepared in compliance with such instrument, form, and companion policy. 9) As of the effective date of the Technical Report, to the best of my knowledge, information and belief, the portions of the Technical Report for which I am responsible contain all scientific and technical information that is required to be disclosed to make the Technical Report not misleading. 10) I consent to the filing of the Technical Report with any securities regulatory authority, stock exchange and other regulatory authority and any publications by them, including electronic publication in the public company files on their websites accessible by the public. Dated this 22nd day of September, 2020 Signed, Sealed “Rex Clair Bryan, Ph.D., SME RM” Signature of Qualified Person Rex Clair Bryan, Ph.D., SME RM Print Name of Qualified Person

CERTIFICATE OF QUALIFIED PERSON Anthony Clark, P.E., P.Eng Area Lead Mechanical Engineer POWER Engineers, Inc. 2041 South Cobalt Point Way Meridian, Idaho 83642 Telephone: (208) 288-6100 Facsimile: (208) 288-6199 Email: tony.clark@powereng.com This certificate applies to the report entitled: “NI 43-101 Technical Report – Mt Todd Gold Project – 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia” (“Technical Report”), effective date September 10, 2019, issued on October 7, 2019, and as amended September 22, 2020. I, Anthony Clark, P.E., do hereby certify that: 1) I am a Senior Mechanical Engineer with POWER Engineers, Inc. with a business address at 2041 S. Cobalt Point Way, Meridian, Idaho, 83642, USA. 2) I graduated with a degree in Mechanical Engineering, Bachelor of Science in 2001 from the Missouri University of Science and Technology, Rolla, Missouri. I have worked as a Mechanical Engineer for a total of 18 years since my graduation. My relevant experience is in the area of electrical power plant design. I am a PE in Idaho (No. 14669) and P.Eng in Alberta (No. 208138). 3) I have read the definition of “qualified person” set out in National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”) and certify that by reason of my education, affiliation with a professional association (as defined in NI 43-101) and past relevant work experience, I fulfill the requirements to be a “qualified person” within the meaning of NI 43-101. 4) I have personally visited and inspected the property which is the subject of the Technical Report on June 28th through June 29th, 2017 to inspect the existing power infrastructure at the site, natural gas pipeline, and power rights-of-way. 5) I am responsible for Sections 18.8, 21.1.3, and 21.2.4 of the Technical Report. 6) I am independent of the issuer, Vista Gold Corp., according to Section 1.5 of NI 43-101. 7) I have had prior involvement with the property that is the subject of the Technical Report. My involvement has consisted of acting as a supporting engineer primarily in the area of power station feasibility since 2013. My involvement has also consisted of acting as a qualified person who was relied upon for the NI 43-101 Technical Report – Mt Todd Gold Project 50,000 tpd Preliminary Feasibility Study amended and restated July 7, 2014; and the NI 43-101 Technical Report – Mt Todd Gold Project, 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia, issue date March 2, 2018. 8) I have read NI 43-101, Form 43-101F1 – Technical Report, 43-101CP – Standards of Disclosure for Mineral Projects, and the Technical Report has been prepared in compliance with such instrument, form, and companion policy. 9) As of the effective date of the Technical Report, to the best of my knowledge, information and belief, the portions of the Technical Report for which I am responsible contain all scientific and technical information that is required to be disclosed to make the Technical Report not misleading. 10) I consent to the filing of the Technical Report with any securities regulatory authority, stock exchange and other regulatory authority and any publications by them, including electronic publication in the public company files on their websites accessible by the public. Dated this 22nd day of September, 2020 Signed, Sealed “Anthony Clark, P.E., P.Eng” Signature of Qualified Person Anthony Clark, P.E., P.Eng Print Name of Qualified Person

CERTIFICATE OF QUALIFIED PERSON Thomas L. Dyer, P.E., SME RM Mining Engineer Mine Development Associates 210 South Rock Boulevard Reno, Nevada 89502 Telephone: (775) 856-5700 Email: tdyer@mda.com This certificate applies to the report entitled: “NI 43-101 Technical Report – Mt Todd Gold Project – 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia” (“Technical Report”), effective date September 10, 2019, issued on October 7, 2019, and as amended September 22, 2020. I, Thomas L. Dyer, P.E., do hereby certify that: 1) I am a Senior Engineer with Mine Development Associates with a business address at 210 Rock Blvd, Reno, NV, 89502, USA. 2) I graduated with a B.S. degree in Mine Engineering in 1996 from the South Dakota School of Mines and Technology. I have worked as a Mining Engineer for a total of 23 years since my graduation. My relevant experience includes 11 years of Engineering in an operating open pit mine including underground studies. This operations experience included increasing responsibilities obtaining the position of Chief Engineer. Since that time I have worked as a Consulting Mining Engineer for numerous open pit and underground projects including Preliminary Economic Assessments, Prefeasibility, and Feasibility studies. I am a P.E. in Nevada (No. 15729) and am a Registered Member of SME (# 4029995RM) in good standing. 3) I have read the definition of “qualified person” set out in National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”) and certify that by reason of my education, affiliation with a professional association (as defined in NI 43-101) and past relevant work experience, I fulfill the requirements to be a “qualified person” within the meaning of NI 43- 101. 4) I have personally visited and inspected the property which is the subject of the Technical Report in July of 2017 for 2 days. 5) I am responsible for Sections 1.6, 1.7, 1.15.3, 15 (Except 15.6), 16, 21.1.1, 21.2.1, 25.3, and 26.3 of the Technical Report. 6) I am independent of the issuer, Vista Gold Corp., according to Section 1.5 of NI 43-101. 7) I have had prior involvement with the property that is the subject of the Technical Report. My involvement has consisted of acting as a Qualified Person and author for the NI 43-101 Technical Report – Mt Todd Gold Project, 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia, issue date March 2, 2018; the NI 43-101 Technical Report – Mt Todd Gold Project 50,000 tpd Preliminary Feasibility Study amended and restated July 7, 2014; the 10.65 Mtpy Preliminary Feasibility Study NI 43-101 Technical Report Mt Todd Gold Project dated January 18, 2011; and the Preliminary Feasibility Study NI 43-101 Technical Report Mt Todd Gold Project dated October 1, 2010. 8) I have read NI 43-101, Form 43-101F1 – Technical Report, 43-101CP - Standards of Disclosure for Mineral Projects, and the Technical Report has been prepared to be compliant with such instrument, form, and companion policy. 9) As of the effective date of the Technical Report, to the best of my knowledge, information and belief, the portions of the Technical Report for which I am responsible contain all scientific and technical information that is required to be disclosed to make the Technical Report not misleading. 10) I consent to the filing of the Technical Report with any securities regulatory authority, stock exchange and other regulatory authority and any publications by them, including electronic publication in the public company files on their websites accessible by the public. Dated this 22nd day of September, 2020 Signed, Sealed “Thomas L. Dyer, P.E., SME RM” Signature of Qualified Person Thomas L. Dyer, P.E., SME RM Print Name of Qualified Person

CERTIFICATE OF QUALIFIED PERSON April Hussey, P.E. Environmental Engineer Tetra Tech, Inc. 350 Indiana Street, Suite 500 Golden, Colorado 80401 Telephone: (303) 217-5700 Email: April.Hussey@tetratech.com This certificate applies to the report entitled: “NI 43-101 Technical Report – Mt Todd Gold Project – 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia” (“Technical Report”), effective date September 10, 2019, issued on October 7, 2019, and as amended September 22, 2020. I, April Hussey, P.E., do hereby certify that: 1) I am an Environmental Engineer with Tetra Tech, Inc. with a business address at 350 Indiana Street, Suite 500, Golden, Colorado, 80401, United States of America. 2) I graduated with a Bachelor of Science degree in Chemical Engineering in 2001 from Montana State University, Bozeman, Montana. In addition, I graduated with a Master of Science degree in Civil Engineering. in 2005 from the University of Colorado, Boulder, Colorado. I have worked as an Environmental Engineer for a total of 15 years since my graduation. My relevant experience is in the area of mine water management, preparing mine site water balances, evaluating meteorological information, environmental permitting, reclamation, and water treatment operations. I am a P.E. in Colorado (No. 43907). 3) I have read the definition of “qualified person” set out in National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”) and certify that by reason of my education, affiliation with a professional association (as defined in NI 43-101) and past relevant work experience, I fulfill the requirements to be a “qualified person” within the meaning of NI 43-101. 4) I have not visited and inspected the property which is the subject of the Technical Report. 5) I am responsible for Sections 1.15.7, 20.5, 21.1.5, 24.2.1, 25.8 and 26.5 of the Technical Report. 6) I am independent of the issuer, Vista Gold Corp., according to Section 1.5 of NI 43-101. 7) I have had prior involvement with the property that is the subject of the Technical Report. My involvement has consisted of serving as a supporting project engineer primarily in areas of water management and treatment, environmental permitting, and reclamation and closure since 2011. 8) I have read NI 43-101, Form 43-101F1 – Technical Report, 43-101CP – Standards of Disclosure for Mineral Projects, and the Technical Report has been prepared in compliance with such instrument, form, and companion policy. 9) As of the effective date of the Technical Report, to the best of my knowledge, information and belief, the portions of the Technical Report for which I am responsible contain all scientific and technical information that is required to be disclosed to make the Technical Report not misleading. 10) I consent to the filing of the Technical Report with any securities regulatory authority, stock exchange and other regulatory authority and any publications by them, including electronic publication in the public company files on their websites accessible by the public. Dated this 22nd day of September, 2020 Signed, Sealed “April Hussey, P.E.” Signature of Qualified Person April Hussey, P.E. Print Name of Qualified Person

CERTIFICATE OF QUALIFIED PERSON Chris Johns, M.Sc., P.Eng. Geological Engineer Tetra Tech, Inc. 1715 Dickson Avenue, Suite 150 Kelowna, British Columbia V1Y 9G6 Telephone: (250) 862-4832 Email: Chris.Johns@tetratech.com This certificate applies to the report entitled: “NI 43-101 Technical Report – Mt Todd Gold Project – 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia” (“Technical Report”), effective date September 10, 2019, issued on October 7, 2019, and as amended September 22, 2020. I, Chris Johns, M.Sc., P.Eng., do hereby certify that: 1) I am a Senior Consultant with Tetra Tech, Inc. with a business address at 150-1715 Dickson Avenue, Kelowna, British Columbia, Canada. 2) I graduated with a degree in Geological Engineering, B.Sc., in 1994 from Queen’s University, Kingston, Ontario. In addition, I graduated with a degree in Environmental Engineering, M.Sc. in 1999 from the University of Alberta, Edmonton, AB. I have worked as a geological engineer for a total of 20 years since my graduation. My relevant experience is in the area of tailings storage facility design from scoping study through feasibility and construction stage. I am a registered Professional Engineer in the Provinces of Alberta and British Columbia, and a Chartered Professional Engineer with the Institution of Engineers Australia. 3) I have read the definition of “qualified person” set out in National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”) and certify that by reason of my education, affiliation with a professional association (as defined in NI 43-101) and past relevant work experience, I fulfill the requirements to be a “qualified person” within the meaning of NI 43- 101. 4) I personally visited and inspected the property which is the subject of the Technical Report on June 28th and June 29th, 2017. 5) I am responsible for Sections 1.15.9, 1.15.10, 18.2.4, 21.1.8, 21.2.6, 24.1, 26.7 and 26.8 of the Technical Report. 6) I am independent of the issuer, Vista Gold Corp., according to Section 1.5 of NI 43-101. 7) I have prior involvement with the property that is the subject of the Technical Report. My involvement consisted of acting as a qualified person for the NI 43-101 Technical Report – Mt Todd Gold Project, 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia, issue date March 2, 2018. 8) I have read NI 43-101, Form 43-101F1 – Technical Report, 43-101CP – Standards of Disclosure for Mineral Projects, and the Technical Report has been prepared in compliance with such instrument, form, and companion policy. 9) As of the effective date of the Technical Report, to the best of my knowledge, information and belief, the portions of the Technical Report for which I am responsible contain all scientific and technical information that is required to be disclosed to make the Technical Report not misleading. 10) I consent to the filing of the Technical Report with any securities regulatory authority, stock exchange and other regulatory authority and any publications by them, including electronic publication in the public company files on their websites accessible by the public. Dated this 22nd day of September, 2020 Signed, Sealed “Chris Johns, M.Sc., P.Eng.” Signature of Qualified Person Chris Johns, M.Sc., P.Eng. Print Name of Qualified Person

CERTIFICATE OF QUALIFIED PERSON Deepak Malhotra, Ph.D., SME RM Principal Metallurgist Pro Solv, LLC 15450 W. Asbury Avenue Lakewood, Colorado 80228 Email: deepak@rdiminerals.com This certificate applies to the report entitled: “NI 43-101 Technical Report – Mt Todd Gold Project – 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia” (“Technical Report”), effective date September 10, 2019, issued on October 7, 2019, and as amended September 22, 2020. I, Deepak Malhotra, Ph.D., do hereby certify that: 1) I am the President of Pro Solv, LLC, with a business address at 15450 W. Asbury Avenue, Lakewood, Colorado 80228. 2) I graduated with a degree in Metallurgical Engineering, Master of Science in 1973 from the Colorado School of Mines in Golden, Colorado. In addition, I graduated with a degree in Mineral Economics, Ph.D. in 1978 from the Colorado School of Mines in Golden, Colorado. My relevant experience includes working as a metallurgist and mineral economist for a total of 46 years since my graduation with specific expertise in mineral processing, metallurgical testing, and recovery methods. I am a member of the Society of Mining Engineers. 3) I have read the definition of “qualified person” set out in National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”) and certify that by reason of my education, affiliation with a professional association (as defined in NI 43-101) and past relevant work experience, I fulfill the requirements to be a “qualified person” within the meaning of NI 43-101. 4) I have not visited and inspected the property which is the subject of the Technical Report. 5) I am responsible for Sections 1.6.1, 1.8, 1.9, 1.15.4, 1.15.11, 6.5, 6.6, 13, 15.6, 17, 25.4, 26.9, and 26.11 of the Technical Report. 6) I am independent of the issuer, Vista Gold Corp., according to Section 1.5 of NI 43-101. 7) I have had prior involvement with the property that is the subject of the Technical Report. My involvement has consisted of acting as an expert who was relied upon for the Process Development of the project. I was a qualified person for the NI 43-101 Technical Report – Mt Todd Gold Project, 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia, issue date March 2, 2018; the NI 43-101 Technical Report – Mt Todd Gold Project 50,000 tpd Preliminary Feasibility Study amended and restated: July 7, 2014; the Amended and Restated NI 43-101 Technical Report Resource Update Mt Todd Gold Project, Issue Date of Amendment and Restatement: April 11, 2012; the 10.65 Mtpy Preliminary Feasibility Study NI 43-101 Technical Report Mt Todd Gold Project dated January 18, 2011; and the Preliminary Feasibility Study NI 43-101 Technical Report Mt Todd Gold Project dated October 1, 2010. 8) I have read NI 43-101, Form 43-101F1 – Technical Report, 43-101CP – Standards of Disclosure for Mineral Projects, and the Technical Report has been prepared in compliance with such instrument, form, and companion policy. 9) As of the effective date of the Technical Report, to the best of my knowledge, information and belief, the portions of the Technical Report for which I am responsible contain all scientific and technical information that is required to be disclosed to make the Technical Report not misleading. 10) I consent to the filing of the Technical Report with any securities regulatory authority, stock exchange and other regulatory authority and any publications by them, including electronic publication in the public company files on their websites accessible by the public. Dated this 22nd day of September, 2020 Signed, Sealed “Deepak Malhotra, Ph.D., SME RM” Signature of Qualified Person Deepak Malhotra, Ph.D., SME RM Print Name of Qualified Person

CERTIFICATE OF QUALIFIED PERSON Jessica I. Monasterio, P.E. Professional Engineer 7991 Schaffer Parkway, Suite 100 Littleton, Colorado 80127 Telephone: (303) 799-9015 Email: jspriet@gmail.com This certificate applies to the report entitled: “NI 43-101 Technical Report – Mt Todd Gold Project – 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia” (“Technical Report”), effective date September 10, 2019, issued on October 7, 2019, and as amended September 22, 2020. I, Jessica I. Monasterio, P.E., do hereby certify that: 1) I am a Professional Engineer and completed this study while working for JDS Energy & Mining, Inc. in Golden, Colorado. 2) I graduated with a degree in Geological Engineering, Bachelor of Science in 2006 from the Colorado School of Mines, Golden, Colorado. In addition, I graduated with a degree in Geological Engineering, Master of Engineering in 2007 from the Colorado School of Mines, Golden, Colorado. I have worked as a Geological Engineer for six years, and a Mineral Economist for eight years, for a total of fourteen years since my undergraduate degree. My relevant experience for the past eight years has been developing economic models. I have been a registered Professional Engineer in the State of Colorado (P.E. 0045454) for 11 years and am a member of the Society of Mining, Metallurgy & Exploration. 3) I have read the definition of “qualified person” set out in National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”) and certify that by reason of my education, affiliation with a professional association (as defined in NI 43-101) and past relevant work experience, I fulfill the requirements to be a “qualified person” within the meaning of NI 43-101. 4) I have not visited and inspected the property which is the subject of the Technical Report. 5) I am responsible for Sections 1.11, 1.13, 1.14, 19, 21 (Introduction), 21.1 (Introduction), 21.2 (Introduction), and 22 of the Technical Report. 6) I am independent of the issuer, Vista Gold Corp., according to Section 1.5 of NI 43-101. 7) I have had as part of my employment at JDS Energy & Mining, Inc. and Tetra Tech Inc., prior involvement with the property that is the subject of the Technical Report. My involvement has consisted of acting as an expert who was relied upon for the NI 43-101 Technical Report – Mt Todd Gold Project, 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia, issue date March 2, 2018. 8) I have read NI 43-101, Form 43-101F1 – Technical Report, 43-101CP - Standards of Disclosure for Mineral Projects, and the Technical Report has been prepared in compliance with such instrument, form, and companion policy. 9) As of the effective date of the Technical Report, to the best of my knowledge, information and belief, the portions of the Technical Report for which I am responsible contain all scientific and technical information that is required to be disclosed to make the Technical Report not misleading. 10) I consent to the filing of the Technical Report with any securities regulatory authority, stock exchange and other regulatory authority and any publications by them, including electronic publication in the public company files on their websites accessible by the public. Dated this 22nd day of September, 2020 Signed, Sealed “Jessica I. Monasterio, P.E.” Signature of Qualified Person Jessica I. Monasterio, P.E. Print Name of Qualified Person

CERTIFICATE OF QUALIFIED PERSON Zvonimir Ponos, BE, MIEAust, CPeng, NER General Manager Engineering Coffey Services Australia Pty Ltd (trading as Tetra Tech Proteus) Level 1, 235 St Georges Terrace, Perth, Western Australia 6000 Telephone: +61-8-6218-2100 Email: zvon.ponos@tetratech.com This certificate applies to the report entitled: “NI 43-101 Technical Report – Mt Todd Gold Project – 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia” (“Technical Report”), effective date September 10, 2019, issued on October 7, 2019, and as amended September 22, 2020. I, Zvonimir Ponos, BE, MIEAust, CPeng, NER, do hereby certify that: 1) I am a General Manager of Engineering with Coffey Services Australia Pty Ltd (trading as Tetra Tech Proteus) with a business address at Level 1, 235 St Georges Terrace, Perth, Western Australia, 6000, Australia. 2) I graduated with a degree in Structural Engineering in 1985 from the University of Belgrade in Yugoslavia. I have worked as a Design Engineer, Engineering Manager and Project Manager for more than 30 years since my graduation. My relevant experience is in the areas of structural design, engineering management and project management of chemical, mineral processing and materials handling projects in Gold, Iron Ore, Mineral Sands, Alumina and Base Metals. 3) I am a Chartered Professional Engineer and a Member of the Institution of Engineers Australia (No. 230033). I am also Member of Concrete Institute of Australia (CIA) and Australian Steel Institute (No. 6184). I am a (lapsed) member of both Australian Institute of Project Management (AIPM No 2765) and Project Management Institute, USA (PMI No 167332). All memberships in good standing. 4) I have read the definition of “qualified person” set out in National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”) and certify that by reason of my education, affiliation with a professional association (as defined in NI 43-101) and past relevant work experience, I fulfill the requirements to be a “qualified person” within the meaning of NI 43-101. 5) I have personally visited and inspected the property which is the subject of the Technical Report on the 28th June 2017 for three (3) days. 6) I am responsible for Sections 1.10, 1.15.5, 18.1, 18.2, 18.2.1, 18.2.2, 18.2.3, 18.2.5, 18.2.6, 18.3, 18.4, 18.5, 18.6, 18.7, 21.2.1, 21.2.3, 21.2.7, 24.6, 25.5 and 25.6 of the Technical Report. 7) I am independent of the issuer, Vista Gold Corp., according to Section 1.5 of NI 43-101. 8) I have had prior involvement with the property that is the subject of the Technical Report. My involvement has consisted of acting as a qualified person for the NI 43-101 Technical Report – Mt Todd Gold Project, 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia, issue date March 2, 2018. 9) I have read NI 43-101, Form 43-101F1 – Technical Report, 43-101CP – Standards of Disclosure for Mineral Projects, and the Technical Report has been prepared in compliance with such instrument, form, and companion policy. 10) As of the effective date of the Technical Report, to the best of my knowledge, information and belief, the portions of the Technical Report for which I am responsible contain all scientific and technical information that is required to be disclosed to make the Technical Report not misleading. 11) I consent to the filing of the Technical Report with any securities regulatory authority, stock exchange and other regulatory authority and any publications by them, including electronic publication in the public company files on their websites accessible by the public. Dated this 22nd day of September, 2020 Signed, Sealed “Zvonimir Ponos, BE, MIEAust, CPeng, NER” Signature of Qualified Person Zvonimir Ponos, BE, MIEAust, CPeng, NER Print Name of Qualified Person

CERTIFICATE OF QUALIFIED PERSON David M. Richers, Ph.D., SME RM, CPG, REM Independent Consulting Geologist/Geochemist NEXUS Geos LLC 2708 Lookout View Drive Golden, CO 80401 Telephone: (720)-878-3379 Email: dr.richers@gmail.com This certificate applies to the report entitled: “NI 43-101 Technical Report – Mt Todd Gold Project – 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia” (“Technical Report”), effective date September 10, 2019, issued on October 7, 2019, and as amended September 22, 2020. I, David M. Richers, PhD, SME Rm, CPGt, do hereby certify that: 1) I am an independent Professional Certified Geologist/Geochemist, consultant with NEXUS Geos LLC, 2708 Lookout View Drive, Golden, CO 80401. 2) I received a BS degree in Geology from the Pennsylvania State University, University Park, PA, in 1974, an MS in Geology/Geochemistry from the University of Kentucky, Lexington, KY in 1977, and a Doctorate in Geology/Geochemistry from the University of Kentucky, Lexington, KY in 1980. My relevant experience is in the area of geochemistry, petrology, hydrogeology, and geological environmental assessment for over 40 years. This experience includes geochemical site characterization services and mine geology on projects in the United States, Australia, Spain, and Canada, including both surface and underground operations. My duties routinely included participation in geochemical studies and programs aimed at protecting the environment, including quantification of geochemical processes for engineering design, closure planning and impact analysis. My background also includes extensive work with acid rock drainage and metal leaching (ARD/ML) and the associated fate and transport. I also have expertise in geologic computer mapping and 3D GIS. I am a Certified Professional Geologist with the AAPG (#2913) and a Registered Member of SME (# 04174527 RM) in good standing. 3) I have read the definition of “qualified person” set out in National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”) and certify that by reason of my education, affiliation with a professional association (as defined in NI 43-101) and past relevant work experience, I fulfill the requirements to be a “qualified person” within the meaning of NI 43- 101. 4) I have not visited and inspected the property which is the subject of the Technical Report. 5) I am responsible for Sections 1.15.12, 24.3, and 26.10 of the Technical Report. 6) I am independent of the issuer, Vista Gold Corp., according to Section 1.5 of NI 43-101. 7) I have had prior involvement with the property that is the subject of the Technical Report. My involvement has consisted of acting as a qualified person for the NI 43-101 Technical Report – Mt Todd Gold Project, 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia, Amended & Restated; July 7, 2014. 8) I have read NI 43-101, Form 43-101F1 – Technical Report, 43-101CP - Standards of Disclosure for Mineral Projects, and the Technical Report has been prepared in compliance with such instrument, form, and companion policy. 9) As of the effective date of the Technical Report, to the best of my knowledge, information and belief, the portions of the Technical Report for which I am responsible contain all scientific and technical information that is required to be disclosed to make the Technical Report not misleading. 10) I consent to the filing of the Technical Report with any securities regulatory authority, stock exchange and other regulatory authority and any publications by them, including electronic publication in the public company files on their websites accessible by the public. Dated this 22nd day of September, 2020 Signed, Sealed “David M. Richers , Ph.D., SME RM, CPG, REM” Signature of Qualified Person David M. Richers, Ph.D., SME RM, CPG, REM Print Name of Qualified Person

CERTIFICATE OF QUALIFIED PERSON Vicki J. Scharnhorst, P.E., LEED AP Principal Tetra Tech, Inc. 1560 Broadway, Suite 1400 Denver, Colorado 80202 Telephone: (303) 825-5999 Facsimile: (303) 825-0642 Email: Vicki.Scharnhorst@tetratech.com This certificate applies to the report entitled: “NI 43-101 Technical Report – Mt Todd Gold Project – 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia” (“Technical Report”), effective date September 10, 2019, issued on October 7, 2019, and as amended September 22, 2020. I, Vicki J. Scharnhorst, P.E., LEED AP, do hereby certify that: 1) I am a Principal Consultant with Tetra Tech with a business address at 1560 Broadway, Denver, CO 80202, USA. 2) I graduated with a Bachelor of Science degree in Civil Engineering in 1982 from Kansas State University, Manhattan, Kansas. In addition, I graduated with a Master of Public Administration and Policy degree in 2017 from the American University, Washington D.C. I have worked as a civil engineer for a total of 36 years since my graduation. My relevant experience includes civil engineering on large infrastructure projects inclusive of civil works, water quality programs, environmental impact studies, and permitting. I am a licensed Engineer in the states of Nevada (No. 7647), Michigan (No. 43541), Missouri (No. 27930), and Colorado (No. 41466); a water right surveyor in the State of Nevada; and a LEED Accredited Professional with the U.S. Green Building Council. 3) I have read the definition of “qualified person” set out in National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”) and certify that by reason of my education, affiliation with a professional association (as defined in NI 43-101) and past relevant work experience, I fulfill the requirements to be a “qualified person” within the meaning of NI 43-101. 4) I have personally visited and inspected the property which is the subject of the Technical Report on June 28th and June 29th, 2017 for two days. 5) I am responsible for Sections 1.1, 1.2, 1.3, 1.12, 1.15.1, 1.15.6, 2, 3, 4, 5, 18.0 (Introduction), 20, 21.1.5, 21.1.6, 21.1.7, 21.2.5, 23, 24.0 (Introduction), 24.2, 24.2.2, 24.4, 25.1, 25.7, 26, 26.1, and 26.4 of the Technical Report. 6) I am independent of the issuer, Vista Gold Corp., according to Section 1.5 of NI 43-101. 7) I have had prior involvement with the property that is the subject of the Technical Report. My involvement has consisted of acting as a qualified person for the NI 43-101 Technical Report – Mt Todd Gold Project, 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia, issue date March 2, 2018. 8) I have read NI 43-101, Form 43-101F1 – Technical Report, 43-101CP – Standards of Disclosure for Mineral Projects, and the Technical Report has been prepared in compliance with such instrument, form, and companion policy. 9) As of the effective date of the Technical Report, to the best of my knowledge, information and belief, the portions of the Technical Report for which I am responsible contain all scientific and technical information that is required to be disclosed to make the Technical Report not misleading. 10) I consent to the filing of the Technical Report with any securities regulatory authority, stock exchange and other regulatory authority and any publications by them, including electronic publication in the public company files on their websites accessible by the public. Dated this 22nd day of September, 2020 Signed, Sealed “Vicki J. Scharnhorst, P.E., LEED AP” Signature of Qualified Person Vicki J. Scharnhorst, P.E., LEED AP Print Name of Qualified Person

CERTIFICATE OF QUALIFIED PERSON Keith Thompson, CPG, member AIPG Professional Geologist Tetra Tech, Inc. 1100 McCaslin Boulevard, Suite 150 Superior, Colorado 80027 Telephone: (303) 664-4630 Email: Keith.Thompson@tetratech.com This certificate applies to the report entitled: “NI 43-101 Technical Report – Mt Todd Gold Project – 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia” (“Technical Report”), effective date September 10, 2019, issued on October 7, 2019, and as amended September 22, 2020. I, Keith Thompson, CPG, PG, do hereby certify that: 1) I am a Senior Hydrogeologist with Tetra Tech with a business address at 1100 McCaslin Boulevard, Suite 150, Superior, Colorado 80027, USA. 2) I graduated with Bachelor of Science degree in Geology in 1975 from Youngstown State University, Youngstown, Ohio, USA. In addition, I graduated with a Master of Science degree in Geology in 1979 from the University of Wyoming, Laramie, Wyoming, USA. I have worked as a hydrogeologist for a total of 40 years since my graduation. My relevant experience is in the areas of mining hydrology and hydrogeology, environmental hydrology and hydrogeology, and groundwater flow and transport modeling. I am a Certified Professional Geologist (No. 6005) and member of the American Institute of Professional Geologists and a licensed Professional Geologist in the (USA) states of Alaska (No. 700), California (No. 5572), Idaho (No. 726), Utah (No. 5258797-2250) and Wyoming (No. 2454). 3) I have read the definition of “qualified person” set out in National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”) and certify that by reason of my education, affiliation with a professional association (as defined in NI 43-101) and past relevant work experience, I fulfill the requirements to be a “qualified person” within the meaning of NI 43-101. 4) I have not visited and inspected the property which is the subject of the Technical Report. 5) I am responsible for Sections 1.15.8, 21.1.4, 21.2.2, 24.5, 26.6 of the Technical Report. 6) I am independent of the issuer, Vista Gold Corp., according to Section 1.5 of NI 43-101. 7) I have had prior involvement with the property that is the subject of the Technical Report. My involvement has consisted of acting as a qualified person for “NI 43-101 Technical Report – Mt Todd Gold Project 50,000 tpd Preliminary Feasibility Study, Northern Territory, Australia, Appendix K – Regional Hydrogeology” dated March 2, 2018 and the NI 43-101 Technical Report – Mt Todd Gold Project 50,000 tpd Preliminary Feasibility Study amended and restated: July 7, 2014. 8) I have read NI 43-101, Form 43-101F1 – Technical Report, 43-101CP – Standards of Disclosure for Mineral Projects, and the Technical Report has been prepared in compliance with such instrument, form, and companion policy. 9) As of the effective date of the Technical Report, to the best of my knowledge, information and belief, the portions of the Technical Report for which I am responsible contain all scientific and technical information that is required to be disclosed to make the Technical Report not misleading. 10) I consent to the filing of the Technical Report with any securities regulatory authority, stock exchange and other regulatory authority and any publications by them, including electronic publication in the public company files on their websites accessible by the public. Dated this 22nd day of September, 2020 Signed, Sealed “Keith Thompson, CPG, PG” Signature of Qualified Person Keith Thompson, CPG, PG Print Name of Qualified Person

Vista Gold (VGZ) 8-KRegulation FD Disclosure