NexGen Energy (NXE) 40-F 5 Mar 18 2017 FY Annual report (Canada) Financial data

Document and Entity Information

Document and Entity Information	12 Months Ended
	Dec. 31, 2017shares
Statement [Line Items]
Document Type	40-F
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Trading Symbol	nxe
Entity Registrant Name	NexGen Energy Ltd.
Entity Central Index Key	1,698,535
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding	339,339,356
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well Known Seasoned Issuer	No
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY

CONDENSED STATEMENTS OF FINANCI

CONDENSED STATEMENTS OF FINANCIAL POSITION - CAD	Dec. 31, 2017	Dec. 31, 2016
Current Assets
Cash and cash equivalents	CAD 164,943,850	CAD 31,090,313
Short-term investments	0	47,455,100
Amounts receivable	548,069	807,447
Prepaid expenses	158,875	72,575
Total Current Assets	165,650,794	79,425,435
Non-Current Assets
Deposits	32,927	22,852
Exploration and evaluation assets	152,412,555	109,446,920
Equipment	4,983,074	3,601,178
Total Non-Current Assets	157,428,556	113,070,950
TOTAL ASSETS	323,079,350	192,496,385
Current Liabilities
Accounts payable and accrued liabilities	2,905,179	2,248,912
Flow-through share premium liability	109,251	179,212
Total Current Liabilities	3,014,430	2,428,124
Non-current Liabilities
Deferred income tax liability	280,740	136,588
Deferred lease inducement	73,509	113,606
Convertible debentures	171,369,966	70,811,801
Total Non-Current liabilities	171,724,215	71,061,995
TOTAL LIABILITIES	174,738,645	73,490,119
EQUITY
Share capital	196,311,184	125,735,515
Reserves	28,050,059	17,005,665
Accumulated deficit	(88,038,390)	(32,743,616)
Total Equity, before non-controlling interests	136,322,853	109,997,564
Non-controlling interests	12,017,852	9,008,702
TOTAL EQUITY	148,340,705	119,006,266
TOTAL LIABILITIES AND EQUITY	CAD 323,079,350	CAD 192,496,385

CONSOLIDATED STATEMENTS OF LOSS

CONSOLIDATED STATEMENTS OF LOSS (PROFIT) AND COMPREHENSIVE LOSS (PROFIT) - CAD	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Statement [Line Items]
Salaries, benefits and directors fees	CAD 3,993,277	CAD 3,021,957
Office and administrative	1,502,988	1,214,072
Professional fees	1,725,921	1,007,338
Travel	639,559	506,365
Depreciation	758,063	626,964
Share-based payments	9,183,667	8,100,213
Impairment of exploration and evaluation assets	87,749	964,858
Finance income	(1,305,784)	(466,505)
Mark to market loss (gain) on convertible debentures	27,522,985	(3,311,719)
Interest expense	8,693,847	3,487,001
Convertible debenture issuance costs	2,811,146	4,052,398
Foreign exchange loss (gain)	1,225,599	(2,407,000)
Business acquisition costs of subsidiary	0	565,079
Employee relocation and other costs	0	94,868
Loss on disposal of equipment	24,905	0
Loss (profit) from operations	56,863,922	17,455,889
Deferred income tax expense	(33,312)	75,776
Loss (profit) and comprehensive loss (profit) for the year	56,830,610	17,531,665
Loss (profit) and comprehensive loss (profit) attributable to:
Shareholders of NexGen Energy Ltd.	56,038,329	16,893,468
Non-controlling interests in IsoEnergy Ltd.	792,281	638,197
Loss (profit) and comprehensive loss (profit) for the year	CAD 56,830,610	CAD 17,531,665
Loss (profit) per common share attributable to the Companys common shareholders basic and diluted	CAD 0.17	CAD 0.06
Weighted average number of common shares outstanding basic and diluted	321,921,938	300,298,973

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - CAD	Total	Share Capital [Member]	Reserves [Member]	Accumulated Deficit [Member]	Non-controlling Interests [Member]
Beginning Balance (shares) at Dec. 31, 2015	286,884,616
Beginning Balance at Dec. 31, 2015	CAD 100,155,637	CAD 110,024,398	CAD 7,530,180	CAD (17,398,941)
Statement [Line Items]
Exercise of warrants (shares)	14,787,443
Exercise of warrants	CAD 9,366,182	10,300,543	(934,361)
Exercise of options (shares)	2,941,666
Exercise of options	CAD 1,217,060	1,943,634	(726,574)
Share issuance costs	CAD (12)	(12)
Issue of shares for exploration and evaluation assets (shares)	49,861
Issue of shares for exploration and evaluation assets	CAD 48,864	48,864
Issue of shares on convertible debenture financing (shares)	1,005,586
Issue of shares on convertible debenture financing	CAD 2,292,480	2,292,480
Issue of shares on convertible debenture interest payment (shares)	521,115
Issue of shares on convertible debenture interest payment	CAD 1,125,608	1,125,608
Share-based payments	11,136,420		11,136,420
Issue of shares of subsidiary to non-controlling interests	11,195,692			1,548,793	CAD 9,646,899
Loss for the period	CAD (17,531,665)			(16,893,468)	(638,197)
Ending Balance (shares) at Dec. 31, 2016	306,190,287
Ending Balance at Dec. 31, 2016	CAD 119,006,266	125,735,515	17,005,665	(32,743,616)	9,008,702
Statement [Line Items]
Exercise of warrants (shares)	5,714,286
Exercise of warrants	CAD 2,857,143	2,857,143
Exercise of options (shares)	1,424,445
Exercise of options	CAD 1,128,032	1,981,132	(853,100)
Share issuance costs	CAD (2,519,632)	(2,519,632)
Issue of shares for cash from private placement (shares)	24,146,424
Issue of shares for cash from private placement	CAD 62,745,000	62,745,000
Issue of shares for exploration and evaluation assets (shares)	111,110
Issue of shares for exploration and evaluation assets	CAD 333,330	333,330
Issue of shares on convertible debenture financing (shares)	869,271
Issue of shares on convertible debenture financing	CAD 2,258,820	2,258,820
Issue of shares on convertible debenture interest payment (shares)	883,533
Issue of shares on convertible debenture interest payment	CAD 2,919,876	2,919,876
Share-based payments	12,493,458		12,493,458
Reserve re-allocation for expired warrants			(595,964)	595,964
Issue of shares of subsidiary to non-controlling interests	3,949,022			147,591	3,801,431
Loss for the period	CAD (56,830,610)			(56,038,329)	(792,281)
Ending Balance (shares) at Dec. 31, 2017	339,339,356
Ending Balance at Dec. 31, 2017	CAD 148,340,705	CAD 196,311,184	CAD 28,050,059	CAD (88,038,390)	CAD 12,017,852

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS	12 Months Ended
	Dec. 31, 2017CAD	Dec. 31, 2016CAD
Cash flows (used in) from operating activities
Loss for the year	CAD (56,830,610)	CAD (17,531,665)
Items not involving cash:
Depreciation	758,063	626,964
Share-based payments	9,183,667	8,100,213
Amortization of deferred lease inducement	(40,096)	(40,096)
Impairment of exploration and evaluation assets	87,749	964,858
Unrealized foreign exchange loss (gain) on cash and cash equivalents	(258,399)	(965,084)
Deferred income tax expense (recovery)	(33,312)	75,776
Mark to market loss (gain) on convertible debentures	27,522,985	(3,311,719)
Interest expense	8,693,847	3,487,001
Loss on disposal of equipment	24,905	0
Shares of subsidiary issued for business acquisition	0	302,881
Changes in non-cash working capital items:
Amounts receivable	259,378	(501,147)
Prepaid expenses	(86,300)	131,123
Accounts payable and accrued liabilities	(416,299)	641,395
Deposits	(10,075)	(5,452)
Net cash flows from (used in) operating activities	(11,144,497)	(8,024,952)
Cash flows (used in) from investing activities
Acquisition of exploration and evaluation assets	(35,960,842)	(41,148,844)
Acquisition of equipment	(1,859,729)	(2,883,571)
Sale and maturity (acquisition) of short-term investments	47,455,100	(47,455,100)
Receipt of deferred lease inducement payment	0	193,799
Net cash flows from (used in) investing activities	9,634,529	(91,293,716)
Cash flows (used in) from financing activities
Cash from exercise of options and warrants, net of share issuance costs	3,985,175	10,583,230
Shares issued for cash from private placements, net of share issuance costs	60,225,368	0
Shares of subsidiary issued to non-controlling interests for cash, net of share issuance costs	1,017,249	10,132,835
Shares issued in connection with issuance of convertible debentures	2,258,820	2,292,480
Issuance of convertible debentures	73,035,180	74,123,520
Interest paid on convertible debentures	(5,416,686)	(1,992,150)
Net cash flows from (used in) financing activities	135,105,106	95,139,915
Change in cash and cash equivalents	133,595,138	(4,178,753)
Cash and cash equivalents, beginning of period	31,090,313	34,303,982
Effect of exchange rate fluctuations on cash held	258,399	965,084
Cash and cash equivalents at end of period	164,943,850	31,090,313
Cash and cash equivalents consist of:
Cash	153,329,808	9,295,803
Cash equivalents	CAD 11,614,042	CAD 21,794,510

REPORTING ENTITY

REPORTING ENTITY	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
REPORTING ENTITY [Text Block]	1. REPORTING ENTITY NexGen Energy Ltd. (“NexGen” or the “Company”) is an exploration stage entity engaged in the acquisition, exploration and evaluation of uranium properties in Canada. The Company was incorporated pursuant to the provisions of the British Columbia Business Corporations Act th On April 19, 2013, the Company (as it was then called, Clermont Capital Inc. (“Clermont”)) completed its qualifying transaction, which was effected pursuant to an amalgamation agreement dated December 31, 2012 (the “Amalgamation Agreement”) amongst Clermont, 0957633 B.C. Ltd., a wholly owned subsidiary of Clermont, and NexGen Energy Ltd. (“Old NexGen”). Pursuant to the Amalgamation Agreement, the shareholders of Old NexGen were issued one common share of Clermont (on a post-share consolidation basis) for every one Old NexGen common share held immediately prior to the completion of the amalgamation. In connection with the Qualifying Transaction, Clermont also completed a consolidation of its common shares on a 2.35:1 basis and changed its name to “NexGen Energy Ltd.”. The Company’s acquisition of Old NexGen was accounted for as a reverse takeover. The Company commenced trading on the TSX Venture Exchange (“TSX-V”) as a Tier 2 Issuer under the symbol “NXE” on April 23, 2013. On August 7, 2015, the Company became a Tier 1 Issuer. On July 15, 2016, NexGen graduated and commenced trading on the Toronto Stock Exchange (“TSX”) under its existing symbol. The Company’s common shares ceased trading on the OTCQX Best Market under the symbol “NXGEF” upon the commencement of trading on the NYSE American LLC (“NYSE American”) under the symbol “NXE” on May 17, 2017. In February 2016, the Company incorporated four wholly owned subsidiaries: NXE Energy Royalty Ltd., NXE Energy SW1 Ltd., NXE Energy SW3 Ltd., and IsoEnergy Ltd. (collectively, the “Subsidiaries”). The Subsidiaries were incorporated to hold certain exploration assets of the Company. In June 2016, certain exploration and evaluation assets were transferred to each of IsoEnergy Ltd. (“IsoEnergy”), NXE Energy SW1 Ltd. and NXE Energy SW3 Ltd. (Note 5). Subsequent to the transfer, IsoEnergy issued shares to third parties pursuant to external financings and listed its common shares on the TSX-V, with NexGen retaining 63.9% of IsoEnergy’s outstanding common shares as at December 31, 2017.

NATURE OF OPERATIONS

NATURE OF OPERATIONS	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
NATURE OF OPERATIONS [Text Block]	2 NATURE OF OPERATIONS As an exploration stage company, the Company does not have revenues and historically has recurring operating losses. As at December 31, 2017, the Company had an accumulated deficit of $88,038,390 and working capital of $162,745,615. The Company will be required to obtain additional funding in order to continue with the exploration and development of its mineral properties and to repay its convertible debentures (Note 8), if required. The business of exploring for minerals involves a high degree of risk. NexGen is an exploration company and is subject to risks and challenges similar to companies in a comparable stage. These risks include, but are not limited to, the challenges of securing adequate capital; development and operational risks inherent in the mining industry; changes in government policies and regulations; the ability to obtain the necessary environmental permits or, alternatively NexGen's ability to dispose of its exploration and evaluation assets on an advantageous basis; as well as global economic and uranium price volatility; all of which are uncertain. The underlying value of the exploration and evaluation assets is dependent upon the existence and economic recovery of mineral reserves and is subject to, but not limited to, the risks and challenges identified above. Changes in future conditions could require material write-downs of the carrying value of exploration and evaluation assets.

BASIS OF PRESENTATION

BASIS OF PRESENTATION	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
BASIS OF PRESENTATION [Text Block]	3. BASIS OF PRESENTATION Statement of Compliance These consolidated financial statements for the year ended December 31, 2017, including comparatives, have been prepared in accordance with International Financial Reporting Standards (“IFRS”) as issued by the International Accounting Standards Board (“IASB”) and interpretations of the International Financial Reporting Interpretations Committee (“IFRIC”). These consolidated financial statements were authorized for issue by the Board of Directors on March 2, 2018. Basis of Presentation These consolidated financial statements have been prepared on a historical cost basis, except for certain financial instruments which have been measured at fair value, including the convertible debentures issued by the Company (Note 8). In addition, these consolidated financial statements have been prepared using the accrual basis of accounting. All monetary references expressed in these notes are references to Canadian dollar amounts (“$”) except as otherwise noted. These financial statements are presented in Canadian dollars, which is the functional currency of the Company and its subsidiaries. Critical accounting judgments, estimates and assumptions The preparation of the consolidated financial statements requires management to make judgments, estimates and assumptions that affect the reported amounts of assets, liabilities and contingent liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Estimates and assumptions are continuously evaluated and are based on management’s experience and other factors, including expectations of future events that are believed to be reasonable in the circumstances. Uncertainty about these judgments, estimates and assumptions could result in a material adjustment to the carrying amount of the asset or liability affected in future periods. Where the fair value of financial assets and financial liabilities recorded in the financial statements cannot be derived from active markets, their fair value is determined using valuation models. The inputs to these models are taken from observable markets where possible, but where this is not feasible, a degree of judgment is required in establishing fair values. The judgments include considerations of inputs such as liquidity risk, credit risk and volatility. Changes in assumptions about these factors could affect the reported fair value of financial instruments. The information about significant areas of estimation uncertainty considered by management in preparing the financial statements is as follows: (i) Impairment At the end of each financial reporting period the carrying amounts of the Company’s non-financial assets are reviewed to determine whether there is any indication that those assets have suffered an impairment loss or reversal of previous impairment. Where such an indication exists, the recoverable amount of the asset is estimated in order to determine the extent of the impairment, if any. With respect to exploration and evaluation assets, the Company is required to make estimates and judgments about the future events and circumstances regarding whether the carrying amount of intangible exploration assets exceeds its recoverable amount. Recoverability is dependent on various factors, including the discovery of economically recoverable reserves, the ability of the Company to obtain the necessary financing to complete the development and upon future profitable production or proceeds from the disposition of the exploration and evaluation assets themselves. Additionally, there are numerous geological, economic, environmental and regulatory factors and uncertainties that could impact management’s assessment as to the overall viability of its properties or to the ability to generate future cash flows necessary to cover or exceed the carrying value of the Company’s exploration and evaluation assets properties. (ii) Share-based payments The Company uses the Black-Scholes option pricing model to determine the fair value of options and warrants in order to calculate share-based payments expense and the fair value of broker warrants. The Black-Scholes model involves six key inputs to determine fair value of an option: risk-free interest rate, exercise price, market price at date of issue, expected dividend yield, expected life, and expected volatility. Certain of the inputs are estimates that involve considerable judgment and are or could be affected by significant factors that are out of the Company’s control. The Company is also required to estimate the future forfeiture rate of options based on historical information in its calculation of share-based payments expense. Refer to Note 9 for further details. (iii) Convertible debentures The Company uses a system of two coupled Black-Scholes equation model to determine the fair value of the convertible debentures. This model involves five key inputs to determine the fair value of the convertible debentures: risk-free interest rate, credit spread, market price at valuation date, expected dividend yield and historical volatility. Certain of the inputs are estimates that involve considerable judgment and are or could be affected by significant factors that are out of the Company’s control. Refer to Note 8 for further details. The information about significant areas of judgment considered by management in preparing the financial statements are as follows: (i) Deferred tax assets Deferred tax assets are recognized in respect of tax losses and other temporary differences to the extent it is probable that taxable income will be available against which the losses can be utilized. Judgment is required to determine the amount of deferred tax assets that can be recognized based upon the likely timing and level of future taxable income together with future tax planning strategies. Refer to Note 14 for further details. Critical accounting judgments, estimates and assumptions, continued (ii) Going concern The Company’s management has made an assessment of the Company’s ability to continue as a going concern and is satisfied that the Company has the resources to continue its business for the foreseeable future. Furthermore, management is not aware of any material uncertainties that may cast significant doubt upon the Company’s ability to continue as a going concern. Therefore, the financial statements continue to be prepared on a going concern basis. (iii) Exploration and evaluation assets The application of the Company’s accounting policy for exploration and evaluation expenditures requires judgment to determine whether future economic benefits are likely, from either future exploitation or sale, or whether activities have reached a stage which permits a reasonable assessment of the existence of reserves. The determination of reserves and resources is itself an estimation process that requires varying degrees of uncertainty depending on how the resources are classified.

SIGNIFICANT ACCOUNTING POLICIES

SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
SIGNIFICANT ACCOUNTING POLICIES [Text Block]	4. SIGNIFICANT ACCOUNTING POLICIES The significant accounting policies set out below have been applied consistently to all years presented in these financial statements: (a) Functional and Presentation Currency These financial statements are presented in Canadian dollars, which is the functional currency of the Company and its subsidiaries. Translation of transactions and balances Foreign currency transactions are translated into the functional currency using the exchange rates prevailing at the dates of the transactions or valuation where items are re-measured. Monetary assets and liabilities denominated in foreign currencies are translated at the functional currency spot rate of exchange in effect at the reporting date. Non-monetary items that are measured in terms of historical cost in a foreign currency are translated using the exchange rate as at the date of the initial transaction. Translation gains or losses are recognized in profit or loss. (b) Consolidation These consolidated financial statements include the accounts of the Company and its subsidiaries: NXE Energy Royalty Ltd., NXE Energy SW1 Ltd., NXE Energy SW3 Ltd. and IsoEnergy. Shares of IsoEnergy were issued to third parties as part of financings since its inception, thereby resulting in the recognition of non-controlling interests. The financial results of the subsidiaries are included in these consolidated financial statements from the date of incorporation. Intercompany balances and transactions are eliminated on consolidation. The following table sets forth the Company’s ownership percentage in each of its subsidiaries as of December 31, 2017: Name of Subsidiary % Ownership as of December 31, 2017 NXE Energy Royalty Ltd. 100% NXE Energy SW1 Ltd. 100% NXE Energy SW3 Ltd. 100% IsoEnergy Ltd. 63.9% (c) Cash and cash equivalents Cash and cash equivalents include deposits held with banks that are available on demand and guaranteed investment certificates with original maturities of three months or less or that are readily convertible into cash. (d) Exploration and evaluation assets Once the legal rights to explore a property have been obtained, exploration and evaluation costs are capitalized as exploration and evaluation assets on an area of interest basis pending determination of the technical feasibility and the commercial viability of the project. Capitalized costs include costs directly related to exploration and evaluation activities in the area of interest. When a claim is relinquished or a project is abandoned, the related costs are recognized in profit or loss immediately. Proceeds received from the sale of any interest in a property will be credited against the carrying value of the property, with any excess included in operations for the period. If a property is abandoned, the acquisition and deferred exploration costs will be written off to operations. Although the Company has taken steps to verify title to exploration and evaluation assets in which it has an interest, in accordance with industry standards for the current stage of exploration of such properties, these procedures do not guarantee the Company’s title. A property may be subject to unregistered prior agreements or inadvertent non-compliance with regulatory requirements. Management regularly assesses exploration and evaluation assets for events or circumstances that may indicate possible impairment. Once the technical feasibility and commercial viability of the extraction of mineral resources in an area of interest are demonstrable, exploration and evaluation assets attributable to that area of interest are first tested for impairment and then reclassified to mining assets and development assets within property, plant and equipment. (e) Equipment (i) Recognition and measurement Items of equipment are stated at cost less accumulated depreciation and impairment losses. Cost includes expenditures that are directly attributable to the acquisition of the asset. (ii) Subsequent costs The cost of replacing a part of an item in the carrying amount of equipment is recognized when that cost is incurred, if it is probable that the future economic benefits embodied within the item will flow to the Company and the cost of the item can be measured reliably. (iii) Depreciation The carrying amounts of equipment (including initial and subsequent capital expenditures) are amortized to their estimated residual value over the estimated useful lives of the specific assets concerned. Depreciation is calculated over the estimated useful lives of each significant component as follows: - Computing equipment 55% declining balance basis - Software 55% declining balance basis - Field equipment 20% declining balance basis - Leasehold improvements 5 -year lease term - Road 5 -year straight-line basis Depreciation methods, useful lives, and residual values are reviewed at least annually and adjusted if appropriate. (iv) Disposal Gains and losses on disposal of an item of equipment are determined by comparing the proceeds from disposal with the carrying amount of the item of equipment and are recognized in profit or loss. (f) Impairment An impairment loss is recognized when the carrying amount of an asset, or its cash generating unit (“CGU”), exceeds its recoverable amount. A CGU is the smallest identifiable group of assets that generates cash inflows that are largely independent of the cash inflows from other assets or groups of assets. Impairment losses are recognized in profit and loss for the period. Impairment losses recognized in respect of CGUs are allocated first to reduce the carrying amount of any goodwill allocated to CGUs and then to reduce the carrying amount of the other assets in the unit on a pro-rata basis. The recoverable amount of assets is the greater of an asset’s fair value less cost to sell and value in use. In assessing value in use, the estimated future cash flows are discounted to their present value using a pre-tax discount rate that reflects the current market assessments of the time value of money and the risks specific to the asset. For an asset that does not generate cash inflows largely independent of those from other assets, the recoverable amount is determined for the cash-generating unit to which the asset belongs. An impairment loss is only reversed if there is an indication that the impairment loss may no longer exist and there has been a change in the estimates used to determine the recoverable amount, however, not to an amount higher than the carrying amount that would have been determined had no impairment loss been recognized in previous years. Assets that have an indefinite useful life are not subject to depreciation and are tested annually for impairment. (g) Decommissioning and Restoration Provisions Decommissioning and restoration provisions are recorded when a present legal or constructive obligation exists as a result of past events where it is probable that an outflow of resources embodying economic benefits will be required to settle the obligation, and a reliable estimate of the amount of the obligation can be made. The amount recognized as a provision is the best estimate of the consideration required to settle the present obligation at the reporting date, taking into account the risks and uncertainties surrounding the obligation and discount rates. Where a provision is measured using the cash flows estimated to settle the present obligation, its carrying amount is the present value of those cash flows discounted for the market discount rate. Over time the discounted liability is increased for the changes in the present value based on the current market discount rates and liability risks. When some or all of the economic benefits required to settle a provision are expected to be recovered from a third party, the receivable is recognized as an asset if it is virtually certain that reimbursement will be received and the amount receivable can be measured reliably. Changes in reclamation estimates are accounted for prospectively as a change in the corresponding capitalized cost. The Company did not have any decommissioning and restoration provisions for the years presented. (h) Share Capital Common shares are classified as equity. Incremental costs directly attributable to the issue of common shares are recognized as a deduction from equity. Common shares issued for consideration other than cash, are valued based on their market value at the date the shares are issued. The Company has adopted a residual value method with respect to the measurement of shares and warrants issued as private placement units. The residual value method first allocates value to the more easily measurable component based on fair value and then the residual value, if any, to the less easily measurable component. The Company considers the fair value of common shares issued in the private placements to be the more easily measurable component and the common shares are valued at their fair value, as determined by the closing market price on the announcement date. The balance, if any, is allocated to the attached warrants. Any fair value attributed to the warrants is recorded as reserves. (i) Share-based payments The Company’s stock option plan allows Company employees, directors, officers and consultants to acquire shares of the Company. The fair value of options granted is recognized as share-based payments expense with a corresponding increase in equity reserves. The fair value of the options granted is measured using the Black-Scholes option pricing model, taking into account the terms and conditions upon which the options were granted. Fair value is measured at grant date, and each tranche is recognized using the graded vesting method over the period during which the options vest. At each financial reporting date, the amount recognized as an expense is adjusted to reflect the actual number of stock options that are expected to vest. In situations where equity instruments are issued to non-employees and some or all of the goods or services received by the entity as consideration cannot be specifically identified, they are measured at the fair value of the share-based payment. Share-based payment awards to non-employees are measured at the fair value of goods or services received. An individual is classified as an employee when the individual is an employee for legal or tax purposes (direct employee) or provides services similar to those performed by a direct employee. (j) Flow-through shares Resource expenditure deductions for income tax purposes related to exploration activities funded by flow-through share arrangements are renounced to investors under Canadian income tax legislation. On issuance, the Company separates the flow-through share into i) a flow-through share premium, equal to the estimated premium, if any, investors pay for the flow- through feature, which is recognized as a liability and ii) share capital. Upon qualifying expenditures being incurred, the Company recognizes a deferred tax liability for the taxable temporary difference that arises from the difference between the carrying amount of eligible expenditures capitalized as exploration and evaluation assets and its tax base and the premium is recognized as a reduction of deferred tax expense. Proceeds received from the issuance of flow-through shares must be expended on Canadian resource property exploration within a period of two years. Failure to expend such funds as required under the Canadian income tax legislation will result in a Part XII.6 tax to the Company on flow-through proceeds renounced under the “Look-back” Rule. When applicable, this tax is accrued as a financial expense until paid. (k) Financial Instruments The Company classifies its financial assets into one of the following categories as follows: Fair value through profit or loss (“FVTPL”) - Loans and receivables Held-to-maturity investments - Available-for-sale All financial assets except those measured at fair value through profit or loss are subject to review for impairment at least at each reporting date. Financial assets are impaired when there is objective evidence of impairment as a result of one or more events that have occurred after initial recognition of the asset and that event has an impact on the estimated future cash flows of the financial asset or the group of financial assets. Financial liabilities The Company classifies its financial liabilities into one of two categories as follows: Fair value through profit or loss (FVTPL) Other financial liabilities - (l) Loss per Share Basic loss per share is calculated by dividing the loss for the year by the weighted average number of common shares outstanding during the year. The Company uses the treasury stock method to compute the dilutive effect of options, warrants and other similar instruments. Under this method, the weighted average number of shares outstanding used in the calculation of diluted loss per share assumes that the deemed proceeds received from the exercise of stock options, share purchase warrants and their equivalents would be used to repurchase common shares of the Company at the average market price during the period. Existing stock options and share purchase warrants have not been included in the computation of diluted loss per share as to do so would be anti-dilutive. Accordingly, basic and diluted loss per share is the same for the years presented. (m) Income taxes Income tax expense comprises current and deferred tax. Current tax and deferred tax are recognized in profit or loss except to the extent that it relates to items recognized directly in equity or in other comprehensive income. Current tax is the expected tax payable or receivable on the taxable income or loss for the year, using tax rates enacted at the reporting date, and any adjustment to tax payable in respect of previous years. Deferred tax is recognized in respect of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for taxation purposes. Deferred tax is not recognized for the following temporary differences: the initial recognition of assets or liabilities in a transaction that is not a business combination and that affects neither accounting nor taxable profit or loss, and differences relating to investments in subsidiaries and jointly controlled entities to the extent that it is probable that they will not reverse in the foreseeable future. In addition, deferred tax is not recognized for taxable temporary differences arising on the initial recognition of goodwill. Deferred tax is measured at the tax rates that are expected to be applied to temporary differences when they reverse, based on the laws that have been enacted or substantively enacted by the reporting date. Deferred tax assets and liabilities are offset if there is a legally enforceable right to offset current tax liabilities and assets, and they relate to income taxes levied by the same tax authority on the same taxable entity, or on different tax entities, but they intend to settle current tax liabilities and assets on a net basis or their tax assets and liabilities will be realized simultaneously. A deferred tax asset is recognized for unused tax losses, tax credits and deductible temporary differences, to the extent that it is probable that future taxable profits will be available against which they can be utilized. Deferred tax assets are reviewed at each reporting date and are reduced to the extent that it is no longer probable that the related tax benefit will be realized. Change in accounting policy: In the prior year, the proceeds allocated to the flow-through share premium was recognized as “income on reduction of flow-through premium liability” in the consolidated statements of loss and comprehensive loss over the period that the flow-through proceeds were spent on eligible exploration expenditures. Commencing January 1, 2017, this premium is measured on the same basis, however, it is recorded as a deferred tax benefit. The Company voluntarily changed this classification with a view to better present the results of the Company. The impact on the statement of loss and comprehensive loss and statement of cash flows for the year ended December 31, 2016 is a $214,252 reclassification from income on reduction of flow-through premium liability to a reduction of deferred income tax expense. There was no impact on loss and comprehensive loss for 2016, total assets or total shareholders’ equity as at December 31, 2016. Future accounting pronouncements: The following standards have not been adopted by the Company and are being evaluated to determine their impact: • IFRS 9: New standard that replaced IAS 39 for classification and measurement of financial instruments, effective for annual periods beginning on or after January 1, 2018. There are no material differences expected as a result of adopting the new standard. • IFRS 16: New standard that will replace IAS 17 for the accounting and measurement of leases with a term of more than 12 months, effective for annual periods beginning on or after January 1, 2019. The Company does not expect the standard to have a material impact on its financial statements based on the leases in place at December 31, 2017. • IFRS 2: This standard was amended to clarify how to account for certain types of share-based payment transactions, effective for annual periods beginning on or after January 1, 2018. The amendments provide for the accounting of vesting and non-vesting conditions on the measurement of cash-settled share-based payments, share-based payment transactions with a net settlement feature for withholding tax obligations, and a modification to the terms and conditions of a share-based payment that changes the classification of the transaction from cash-settled to equity-settled. The extent of the impact of adoption of the amended standard has not yet been determined.

EXPLORATION AND EVALUATION ASSE

EXPLORATION AND EVALUATION ASSETS	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
EXPLORATION AND EVALUATION ASSETS [Text Block]	5. EXPLORATION AND EVALUATION ASSETS (a) Rook 1 Property The Rook 1 Project is located in Northern Saskatchewan, approximately 40 kilometres (km) east of the Saskatchewan – Alberta border, approximately 150 km north of the town of La Loche and 640 km northwest of the City of Saskatoon and consists of 32 contiguous mineral claims totalling 35,065 hectares. The Rook 1 Project hosts the Arrow deposit discovered in February 2014, the Bow discovery in March 2015, the Harpoon discovery in August 2016 and the Arrow South discovery in July 2017. The Company released an updated mineral resource estimate in March 2017 and the results of a preliminary economic assessment in July 2017, in each case, in respect of the Arrow deposit. NexGen has a 100% interest in the claims subject only to: (i) a 2% net smelter return royalty (“NSR”); and (ii) a 10% production carried interest, in each case, only on claims S- 113928 to S- 113933 (the Arrow deposit is not located on any of these claims). The NSR may be reduced to 1% upon payment of $1 million. The 10% production carried interest provides for the owner to be carried to the date of commercial production. (b) Other Athabasca Basin Properties The Other Athabasca Basin Properties are a portfolio of early stage mineral properties in the Athabasca Basin. The properties are grouped geographically as “SW1”, “SW2” and “SW3”. The SW2 properties are held directly by NexGen. The SW1 and SW3 properties are held by NXE Energy SW1 Ltd. and NXE Energy SW3 Ltd., respectively, each a wholly-owned subsidiary. During the year ended December 31, 2016, the Company recognized an impairment of $964,858 associated with certain Sandhill Lake, Castle South and Castle North properties in the statement of loss and comprehensive loss. During the year ended December 31, 2017, the Company recognized an impairment of $87,749, associated with certain Castle South, Castle North, Castle South Extension and Virgin Trend properties in the statement of loss and comprehensive loss. In respect of both years, the Company decided not to continue exploring some of these claims and allowed them to lapse. (c) IsoEnergy Properties The IsoEnergy Properties consist of (i) a 100% interest in the Radio Project, Saskatchewan (subject to a 2% net smelter return royalty and 2% gross overriding royalty); (ii) a 100% interest in the Thorburn Lake Project, Saskatchewan (subject to a 1% net smelter return royalty and a 10% carried interest which can be reduced to 1% at the holder’s option upon completion of a bankable feasibility study); (iii) a 100% interest, in each of the Madison, 2Z, Carlson Creek and North Thorburn properties, Saskatchewan; (iv) a 100% interest in the Mountain Lake property, Nunavut; (v) a 100% interest in the Geiger property, Saskatchewan; and (vi) a portfolio of newly staked claims in Saskatchewan, all of which are early stage properties. The following is a summary of the capitalized costs on the projects described above. Rook 1 Other Athabasca Properties IsoEnergy Properties Total $ $ $ $ Acquisition costs: Balance, December 31, 2016 $ 230,807 $ 1,124,277 $ 21,438,306 22,793,390 Additions 4,270 333,330 3,298,942 3,636,542 Balance, December 31, 2017 $ 235,077 $ 1,457,607 $ 24,737,248 26,429,932 Deferred exploration costs: Balance, December 31, 2016 $ 77,007,303 $ 4,318,909 $ 5,327,318 $ 86,653,530 Additions: Drilling 20,592,799 3,297 1,168,096 21,764,192 General exploration 2,163,554 25,885 110,603 2,300,042 Geological and geophysical 5,206,266 681,955 521,632 6,409,853 Labour and wages 4,391,456 - 510,398 4,901,854 Share-based payments (Note 9) 2,952,316 - 357,475 3,309,791 Travel 624,265 - 106,845 731,110 35,930,656 711,137 2,775,049 39,416,842 Impairment - (87,749 ) - (87,749 ) Balance, December 31, 2017 $ 112,937,959 $ 4,942,297 $ 8,102,367 $ 125,982,623 Total costs, December 31, 2017 $ 113,173,036 $ 6,399,904 $ 32,839,615 $ 152,412,555 Rook 1 Other Athabasca Properties IsoEnergy Properties Radio Total $ $ $ $ $ Acquisition costs: Balance, December 31, 2015 $ 220,713 1,274,966 - 20,133,753 21,629,432 Additions 10,094 53,864 1,100,000 - 1,163,958 Properties transferred to IsoEnergy - (204,553 ) 20,338,306 (20,133,753 ) - Balance, December 31, 2016 $ 230,807 1,124,277 21,438,306 - 22,793,390 Deferred exploration costs: Balance, December 31, 2015 $ 37,803,918 3,409,339 - 2,293,824 43,507,081 Additions: Drilling 24,989,860 16,061 1,197,163 - 26,203,084 General exploration 2,283,418 8,873 119,460 - 2,411,751 Geological and geophysical 5,333,676 1,991,174 882,866 - 8,207,716 Labour and wages 3,542,893 - 363,420 - 3,906,313 Share-based payments (Note 9) 2,779,787 - 256,420 - 3,036,207 Travel 273,751 - 72,485 - 346,236 39,203,385 2,016,108 2,891,814 - 44,111,307 Properties transferred to IsoEnergy - (141,680 ) 2,435,504 (2,293,824 ) - Impairment - (964,858 ) - - (964,858 ) Balance, December 31, 2016 $ 77,007,303 4,318,909 5,327,318 - 86,653,530 Total costs, December 31, 2016 $ 77,238,110 5,443,186 26,765,624 - 109,446,920

COMMITMENTS

COMMITMENTS	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
COMMITMENTS [Text Block]	6. COMMITMENTS Flow-through expenditures: The Company periodically issues flow-through shares with any resulting flow-through premium recorded as a flow-through share premium liability. The liability is subsequently reduced when the required exploration expenditures are made, and accordingly, a recovery of flow-through premium is then recorded as a reduction of the deferred tax expense. The Company’s subsidiary, IsoEnergy, raised $1,100,000 through the issuance of flow-through shares during the year ended December 31, 2017 and is required to spend such amounts on eligible exploration expenditures before December 31, 2018. As of December 31, 2017, IsoEnergy must fulfill approximately $900,000 of the required exploration expenditures before December 31, 2018. A continuity of the flow-through share premium liability is as follows: Year ended Year ended December 31, 2017 December 31, 2016 Balance, beginning of the year $ 179,212 $ - Liability incurred on flow-through shares issued 130,000 393,464 Settlement of flow-through share liability on expenditure made (199,961 ) (214,252 ) Balance, end of the year $ 109,251 $ 179,212 Office leases: The Company and its subsidiary, IsoEnergy, have total office lease commitments at their Vancouver and Saskatoon offices as follows: 2018 $ 360,975 2019 $ 325,294 2020 $ 199,466 In connection with the Vancouver and Saskatoon office leases, the Company paid deposits of $17,400 and $10,075, respectively, with the landlords which will be applied to the final month’s and final two months’ rents, respectively, when the office lease terms expire. IsoEnergy paid a deposit of $5,452 with its landlord which will be applied to the final month’s rent when the office lease term expires.

EQUIPMENT

EQUIPMENT	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
EQUIPMENT [Text Block]	7. EQUIPMENT Computing Equipment Software Field Equipment Leasehold Improvements Road Total Cost Balance at December 31, 2015 $ 65,490 $ 95,926 $ 1,237,013 $ 183,034 $ - $ 1,581,463 Additions 44,158 184,044 1,519,627 32,138 1,282,890 3,062,857 Balance at December 31, 2016 109,648 279,970 2,756,640 215,172 1,282,890 4,644,320 Additions 125,938 98,763 1,490,880 - 490,695 2,206,276 Disposals - - (29,300 ) - - (29,300 ) Balance at December 31, 2017 $ 235,586 $ 378,733 $ 4,218,220 $ 215,172 $ 1,773,585 $ 6,821,296 Accumulated Depreciation Balance at December 31, 2015 $ 42,259 $ 40,458 $ 305,114 $ 6,101 $ - $ 393,932 Depreciation 24,920 81,119 338,343 41,743 163,085 649,210 Balance at December 31, 2016 67,179 121,577 643,457 47,844 163,085 1,043,142 Depreciation 60,744 114,367 482,738 42,686 98,940 799,475 Disposals - - (4,395 ) - - (4,395 ) Balance at December 31, 2017 $ 127,923 $ 235,944 $ 1,121,800 $ 90,530 $ 262,025 $ 1,838,222 Net book value: At December 31, 2016 $ 42,469 158,393 $ 2,113,183 $ 167,328 $ 1,119,805 $ 3,601,178 At Dectember 31, 2017 $ 107,663 $ 142,789 $ 3,096,420 $ 124,642 $ 1,511,560 $ 4,983,074

CONVERTIBLE DEBENTURES

CONVERTIBLE DEBENTURES	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
CONVERTIBLE DEBENTURES [Text Block]	8. CONVERTIBLE DEBENTURES December 31, 2017 December 31, 2016 2016 Debentures (a) $ 90,742,373 $ 70,811,801 2017 Debentures (b) 80,627,593 - Convertible Debentures $ 171,369,966 $ 70,811,801 (a) 2016 Debentures On June 10, 2016, the Company issued US$60 million principal amount of convertible debentures (the “2016 Debentures”) which were determined to be a hybrid financial instrument comprised of the host debt contract and multiple embedded derivatives. The Company received gross proceeds of $76,416,000 (US$60 million) and net proceeds of $72,363,602 (US$56,852,383) after deducting $4,052,398 (US$3,147,617) in transaction costs from the issue of the 2016 Debentures. A 3% establishment fee of $2,292,480 (US$1.8 million) was also paid to the debenture holders through the issuance of 1,005,586 common shares. The fair value of the 2016 Debentures on issuance date was determined to be $74,123,520 (US$58.2 million). Pursuant to an amended and restated trust indenture dated July 21, 2017, the maturity date of the 2016 Debentures was extended to July 22, 2022. In addition, certain non-financial provisions were removed and superseded by an investor rights agreement between the Company, CEF Holdings Limited and the initial 2016 and 2017 Debenture holders, which agreement contains, among other things, voting alignment provisions. The fair value of the 2016 Debentures increased from $70,811,801 (US$52,738,364) on December 31, 2016 to $90,742,373 (US$72,333,498) at December 31, 2017, resulting in a loss of $19,930,572 (US$15,887,264) for the year ended December 31, 2017. This loss, combined with the loss on the 2017 Debentures (see Note 8(b)) for the year ended December 31, 2017 was recorded in the statement of loss and comprehensive loss. December 31, 2017 December 31, 2016 Fair value of 2016 Debentures, beginning of period $ 70,811,801 $ 74,123,520 Fair value adjustment to December 31, 2017 19,930,572 (3,311,719 ) Interest payable 350,900 369,243 2016 Debentures and interest payable 91,093,273 $ 71,181,044 Less: interest payable included in accounts payable & accrued liabilities (350,900 ) (369,243 ) 2016 Debentures $ 90,742,373 $ 70,811,801 The 2016 Debentures were valued using a convertible bond pricing model based on a system of two coupled Black-Scholes equations where the debt and equity components are separately valued based on different default risks and assumptions. The inputs used in the 2016 Debentures pricing model as at December 31, 2017 and December 31, 2016 are as follows: December 31, 2017 December 31, 2016 Volatility 39.00% 40.00% Expected life in years 4.56 years 4.44 years Risk free interest rate 2.23% 1.91% Expected dividend yield 0% 0% Credit spread 25.35% 26.44% Underlying share price of the Company $ 3.21 $ 2.33 Conversion exercise price US$2.3261 US$2.3261 Exchange rate (C$:US$) $ 0.7971 $ 0.7448 (b) 2017 Debentures On July 21, 2017, the Company issued US$60 million principal amount of convertible debentures (the “2017 Debentures”) which were also determined to be a hybrid financial instrument comprised of the host debt contract and multiple embedded derivatives. The 2017 Debentures have a term of 5 years maturing on July 22, 2022 and bear interest at a rate of 7.5% per annum. The Company received gross proceeds of $75,294,000 (US$60 million) and net proceeds of $72,482,854 (US$57,759,864) after deducting $2,811,146 (US$2,240,136) in transaction costs from the issue of the 2017 Debentures. A 3% establishment fee of $2,258,820 (US$1.8 million) was also paid to the debenture holders through the issuance of 869,271 common shares. The fair value of the 2017 Debentures on issuance date was determined to be $73,035,180 (US$58,200,000). The fair value of the 2017 Debentures increased from $73,035,180 (US$58,200,000) on the initial measurement date to $80,627,593 (US$64,270,700) at December 31, 2017, resulting in a loss of $7,592,413 (US$6,052,143) for the year ended December 31, 2017. This loss, combined with the loss on the 2016 Debentures, for the year ended December 31, 2017 was recorded in loss and comprehensive loss for a total mark to market loss on convertible debentures of $27,522,985 (US$21,938,571). December 31, 2017 Fair value of 2017 Debentures on issuance $ 73,035,180 Fair value adjustment to December 31, 2017 7,592,413 Interest payable 350,900 2017 Debentures and interest payable 80,978,493 Less: interest payable included in accounts payable & accrued liabilities (350,900 ) 2017 Debentures $ 80,627,593 The 2017 Debentures were valued using a convertible bond pricing model based on a system of two coupled Black-Scholes equations where the debt and equity components are separately valued based on different default risks and assumptions. The inputs used in the 2017 Debentures pricing model as at December 31, 2017 and July 21, 2017 are as follows: December 31, 2017 July 21, 2017 Volatility 39.00% 38.00% Expected life in years 4.56 years 5.00 years Risk free interest rate 2.23% 1.88% Expected dividend yield 0% 0% Credit spread 25.35% 25.35% Underlying share price of the Company $ 3.21 $ 3.04 Conversion exercise price US$2.6919 US$2.6919 Exchange rate (C$:US$) $ 0.7971 $ 0.7969 General Terms At inception, for each of the 2016 Debentures and 2017 Debentures (collectively, the “Convertible Debentures”), the Company made an irrevocable election to designate the Convertible Debentures as a financial liability at fair value through profit or loss. At their respective initial recognition date, the entire convertible instrument was measured at fair value with associated transaction costs expensed as incurred. Subsequent to initial recognition, the convertible financial instrument is marked to market at each financial reporting date and any change in fair value is recognized in profit or loss. The Convertible Debentures bear interest at a rate of 7.5% per annum, payable semi-annually in US dollars on June 10 and December 10 in each year, with the first interest payment on the 2017 Debentures having been due on December 10, 2017. Two thirds of the interest (equal to 5% per annum) is payable in cash and one third of the interest (equal to 2.5% per annum) is payable, subject to any required regulatory approval, in common shares of the Company, using the volume-weighted average trading price (“VWAP”) of the common shares on the exchange or market that has the greatest trading volume in the Company’s common shares for the 20 consecutive trading days ending three trading days preceding the date on which such interest payment is due. For this purpose, the VWAP shall be converted into US dollars on each of the 20 days in the period, using the indicative rate of exchange for such currency as reported by the Bank of Canada. The 2016 Debentures and 2017 Debentures are convertible, from time to time, into common shares of the Company at the option of the debenture holders at any time prior to maturity at a price per common share of US$2.3261 and US$2.6919, respectively (the “Conversion Price”). The 2016 Debentures and 2017 Debentures are not redeemable by the Company prior to June 10, 2019 and July 21, 2020, respectively. On or after June 10, 2019 and July 21, 2020 and prior to July 22, 2022, the 2016 Debentures and 2017 Debentures, respectively, may be redeemed by the Company, in whole or in part, at any time that the 20 -day VWAP of the common shares exceeds 130% of the Conversion Price, on not less than 30 days’ prior notice to the debenture holders. For this purpose, the VWAP shall be converted into US dollars on each of the 20 days in the period, using the indicative rate of exchange for such currency as reported by the Bank of Canada. Upon completion of a change of control (which includes in the case of the holders’ right to redeem the Convertible Debentures, a change in the Chief Executive Officer of the Company), the holders of the Convertible Debentures may require the Company to redeem or the Company may require the holders to redeem, as the case may be, any outstanding Convertible Debentures in cash at: (i) on or prior to June 10, 2019 and July 21, 2020 for the 2016 Debentures and 2017 Debentures, respectively, 130% of the principal amount; and (ii) at any time thereafter, 115% of the principal amount, in each case plus accrued but unpaid interest, if any. In addition, upon the public announcement of a change of control that is supported by the Board, the Company may require the holders of the Convertible Debentures to convert the Convertible Debentures into common shares at the Conversion Price provided the consideration payable upon the change of control exceeds the Conversion Price and is payable in cash or in property or securities acceptable to the Debenture holders. A “change of control ”

SHARE CAPITAL AND RESERVES

SHARE CAPITAL AND RESERVES	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
SHARE CAPITAL AND RESERVES [Text Block]	9. SHARE CAPITAL AND RESERVES Authorized Capital Issued For the year ended December 31, 2017: (a) During the year ended December 31, 2017, the Company issued a total of 1,424,445 common shares on the exercise of 199,446 options at a price of $0.24, 100,000 options at a price of $0.40, 50,000 options at a price of $0.425, 200,000 options at a price of $0.46, 300,000 options at a price of $0.50, 83,333 options at a price of $0.62, 250,000 options at a price of $0.64, 16,667 options at a price of $2.24, 58,333 options at a price of $2.65 and 166,666 options at a price of $2.24 for total proceeds of $1,128,032. As a result of the exercises, $853,100 was reclassified from reserves to share capital. (b) In May 2017, the Company issued a total of 5,714,286 common shares on the exercise of 5,714,286 warrants at a price of $0.50 for total proceeds of $2,857,143. (c) On June 12, 2017, the Company issued a total of 327,863 common shares at the then fair value of $963,917 to the holders of the 2016 Debentures for the share portion of the debenture interest payment. (d) On July 21, 2017, the Company completed a private placement pursuant to which it issued a total of 24,146,424 common shares at a price of US$2.0707 for gross proceeds of $62,745,000 (US$50 million). The Company also issued 869,271 common shares valued at $2,258,820 to the debenture holders as part of the establishment fee equal to 3% of the principal amount of the 2017 Debentures. Total share issuance costs for this financing was $2,513,028. (e) On September 18, 2017, the Company issued 111,110 common shares at the then fair value of $333,330 to acquire the remaining 40% interest in the Dufferin Lake property included in the Other Athabasca Basin Properties (Note 5(b)). Total share issuance costs for this transaction was $6,604. (f) On December 12, 2017, the Company issued 555,670 common shares at the then fair value of $1,955,959 to the convertible debenture holders for the share portion of the debenture interest payment. For the year ended December 31, 2016: (a) On January 12, 2016, the Company issued 921,204 common shares and 460,602 common share purchase warrants on the exercise of 921,204 broker warrants at a price of $0.45 for total proceeds of $414,542. On February 11, 2016, the Company issued 460,602 common shares on the exercise of 460,602 common share purchase warrants at a price of $0.65 for additional proceeds of $299,391. As a result of the exercise, $221,089 was reclassified from reserves to share capital. (b) On February 10, 2016 and February 12, 2016, the Company issued a total of 153,534 common shares on the exercise of 153,534 common share purchase warrants at a price of $0.65 for total proceeds of $99,796. (c) On February 26, 2016, the Company issued 49,861 common shares at the then fair value of $48,864 for the acquisition of exploration and evaluation assets included in the Other Athabasca Basin Properties (Note 5b). (d) During the three months ended March 31, 2016, the Company issued a total of 460,603 common shares on the exercise of 307,069 broker warrants and 153,534 common share purchase warrants at an exercise price of $0.45 and $0.65, respectively, for total proceeds of $237,978. As a result of the exercise, $73,697 was reclassified from reserves to share capital. (e) During the three months ended March 31, 2016, the Company issued 12,791,500 common shares on the exercise of 12,791,500 warrants at a price of $0.65 for total proceeds of $8,314,475. As a result of the exercise, $639,575 was re- allocated from reserves to share capital. The Company also issued 190,000 common shares on the exercise of 140,000 options at a price of $0.425 and 50,000 at a price of $0.46 for total proceeds of $82,500. As a result of the exercise, $40,940 was reclassified from reserves to share capital. (f) On June 10, 2016, the Company issued 1,005,586 common shares valued at $2,292,480 to the debenture holders as part of the establishment fee equal to 3% of the principal amount of the 2016 Debentures. (g) During the three months ended June 30, 2016, the Company issued a total of 110,000 common shares on the exercise of 60,000 options at a price of $0.425 and 50,000 options at a price of $0.40 for total proceeds of $45,500. As a result of the exercise, $21,306 was reclassified from reserves to share capital. (h) During the three months ended September 30, 2016, the Company issued a total of 875,000 common shares on the exercise of 800,000 options at a price of $0.40, 50,000 options at a price of $0.46 and 25,000 options at a price of $0.50 for total proceeds of $355,500. As a result of the exercise, $223,607 was reclassified from reserves to share capital. (i) On December 12, 2016, the Company issued 521,115 common shares valued at $1,125,608 to the convertible debenture holders for the share portion of the debenture interest payment. (j) During the three months ended December 31, 2016, the Company issued a total of 1,766,666 common shares on the exercise of 131,914 options at $0.24, 1,218,086 options at $0.40, 133,333 options at $0.46, 200,000 options at $0.50 and 83,333 options at $0.64 for total proceeds of $733,560. As a result of the exercise, $440,721 was reclassified from reserves to share capital. Warrants Warrant transactions and the number of warrants outstanding are summarized as follows: Number of Weighted Average Warrants Exercise Price Outstanding at December 31, 2015 19,918,592 $ 0.59 Exercised (14,787,443 ) 0.63 Issued on exercise of broker warrants 614,137 0.65 Expired (31,000 ) 0.65 Outstanding at December 31, 2016 5,714,286 0.50 Exercised (5,714,286 ) 0.50 Outstanding at December 31, 2017 - $ - Stock Options Pursuant to the Company’s stock option plan, directors may, from time to time, authorize the issuance of options to directors, officers, employees and consultants of the Company, enabling them to acquire up to 20% of the issued and outstanding common shares of the Company. The options can be granted for a maximum term of 10 years and are subject to vesting provisions as determined by the Board of Directors of the Company. Stock option transactions and the number of stock options are summarized as follows: Weighted Number of Average Stock Options Exercise Price Outstanding at December 31, 2015 27,124,446 $ 0.48 Granted 10,200,000 2.45 Exercised (2,941,666 ) 0.41 Expired (116,667 ) 2.65 Forfeited (800,001 ) 1.36 Outstanding at December 31, 2016 33,466,112 $ 1.06 Granted 6,200,000 3.27 Exercised (1,424,445 ) 0.79 Forfeited (383,333 ) 2.53 Outstanding at December 31, 2017 37,858,334 $ 1.42 Number of options exercisable 30,783,334 $ 1.07 As at December 31, 2017, the Company has stock options outstanding and exercisable as follows: Remaining Number of Number Exercise Contractual Options Exercisable Price Life (Years) Expiry Date 3,600,000 3,600,000 $ 0.400 0.08 January 31, 2018 333,334 333,334 $ 1.510 0.19 March 12, 2018 1,450,000 1,450,000 $ 0.400 0.58 July 30, 2018 250,000 250,000 $ 0.300 0.97 December 19, 2018 2,625,000 2,625,000 $ 0.400 1.39 May 23, 2019 750,000 750,000 $ 0.400 1.42 June 2, 2019 4,550,000 4,550,000 $ 0.460 1.98 December 24, 2019 4,200,000 4,200,000 $ 0.500 2.41 May 27, 2020 500,000 500,000 $ 0.620 2.73 September 22, 2020 4,575,000 4,575,000 $ 0.640 2.96 December 16, 2020 250,000 166,667 $ 2.690 3.44 June 8, 2021 5,275,000 3,516,666 $ 2.650 3.48 June 23, 2021 3,300,000 2,200,000 $ 2.240 3.96 December 15, 2021 150,000 50,000 $ 3.300 4.05 January 19, 2022 250,000 83,334 $ 3.110 4.31 April 22, 2022 1,475,000 491,666 $ 2.930 4.87 November 13, 2022 4,325,000 1,441,667 $ 3.390 4.96 December 14, 2022 37,858,334 30,783,334 The Company uses the Black-Scholes option pricing model to calculate the fair value of stock options granted. The model requires management to make estimates, which are subjective and may not be representative of actual results. Changes in assumptions can materially affect estimates of fair values. The following weighted average assumptions were used to estimate the weighted average grant date fair values for the years ended December 31, 2017 and December 31, 2016: December 31, December 31, 2017 2016 Expected stock price volatility 81.72% 87.15% Expected life of options 5.00 years 5.00 years Risk free interest rate 1.53% 0.68% Expected forfeitures 0% 0% Expected dividend yield 0% 0% Weighted average fair value per option granted in the year $ 2.13 $ 1.65 Share-based payments for options vested in the year ended December 31, 2017 amounted to $12,493,458 (2016 – $11,136,420) of which $9,183,667 (2016 – $8,100,213) was expensed to the statement of loss and comprehensive loss and $3,309,791 (2016 - $3,036,207) was capitalized to exploration and evaluation assets (Note 5). Reserves Total Balance, December 31, 2015 $ 7,530,180 Exercise of options (726,574 ) Exercise of warrants (934,361 ) Share-based payments 11,136,420 Balance, December 31, 2016 $ 17,005,665 Exercise of options (853,100 ) Expired warrants adjustment (595,964 ) Share-based payments 12,493,458 Balance, December 31, 2017 $ 28,050,059

RELATED PARTY TRANSACTIONS

RELATED PARTY TRANSACTIONS	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
RELATED PARTY TRANSACTIONS [Text Block]	10. RELATED PARTY TRANSACTIONS Key management personnel include those persons having authority and responsibility for planning, directing and controlling the activities of the Company as a whole. The Company has determined that key management personnel consists of executive and non-executive members of the Company’s Board of Directors, corporate officers and related companies. Remuneration attributed to key management personnel can be summarized as follows: For the years ended December 31, 2017 December 31, 2016 Short-term compensation (1) $ 4,101,441 $ 3,189,845 Share-based payments (stock options) (2) 8,830,606 7,686,442 $ 12,932,047 $ 10,876,287 (1) Short-term compensation to key management personnel for the year ended December 31, 2017 amounted to $4,101,441 (2016 - $3,189,845) of which $3,164,827 (2016 - $2,474,975) was expensed and included in salaries, benefits and directors’ fees on the statement of loss and comprehensive loss. The remaining $936,614 (2016 - $714,870) was capitalized to exploration and evaluation assets. (2) Share-based payments to key management personnel for the year ended December 31, 2017 amounted to $8,830,606 (2016 - $7,686,442) of which $7,696,538 (2016 - $6,921,942) was expensed and $1,134,068 (2016 - $764,500) was capitalized to exploration and evaluation assets. As at December 31, 2017, there was $542,361 (December 31, 2016 - $15,000) included in accounts payable and accrued liabilities owing to its directors and officers for compensation. On October 15, 2015, two corporate officers of the Company were appointed to the Board of Directors of NxGold. During the period ended December 31, 2017, one of the Company’s directors was appointed as a corporate officer of NxGold and two of the Company’s directors were appointed as directors of NxGold. On February 26, 2016, the Company issued 49,861 common shares to NxGold on the exercise of its option to acquire the remaining 25% interest in the Madison and 2Z properties held by NxGold.

CAPITAL MANAGEMENT

CAPITAL MANAGEMENT	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
CAPITAL MANAGEMENT [Text Block]	11. CAPITAL MANAGEMENT The Company manages its capital structure and makes adjustments to it, based on the funds available to the Company, in order to support the acquisition, exploration and evaluation of assets. The Board of Directors does not establish quantitative return on capital criteria for management, but rather relies on the expertise of the Company’s management to sustain the future development of the business. In the management of capital, the Company considers all components of equity and debt and is dependent on third party financing, whether through debt, equity, or other means. Although the Company has been successful in raising funds to date, there is no assurance that the Company will be successful in obtaining required financing in the future or that such financing will be available on terms acceptable to the Company. The properties in which the Company currently has an interest are in the exploration stage. As such the Company has historically relied on the equity markets to fund its activities. The Company will continue to assess new properties and seek to acquire an interest in additional properties if it determines that there is sufficient geologic or economic potential and if it has adequate financial resources to do so. Management reviews its capital management approach on an on-going basis and believes that this approach, given the relative size of the Company, is reasonable. The Company is not subject to externally imposed capital requirements. There were no changes in the Company’s approach to capital management during the year.

FINANCIAL INSTRUMENTS

FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
FINANCIAL INSTRUMENTS [Text Block]	12. FINANCIAL INSTRUMENTS The Company’s financial instruments consist of cash and cash equivalents, amounts receivable, accounts payable and accrued liabilities and the Convertible Debentures. The fair values of the Company’s cash and cash equivalents, amounts receivable and accounts payable and accrued liabilities approximate their carrying value, due to their short-term maturities or liquidity. The Company’s cash and cash equivalents are classified as loans and receivables and are initially recorded at fair value and subsequently at amortized cost with accrued interest recorded in amounts receivable. Fair Value Measurement The Company classifies the fair value of financial instruments according to the following hierarchy based on the amount of observable inputs used to value the instrument: • Level 1 – quoted prices in active markets for identical assets or liabilities. • Level 2 – inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly (i.e. as prices) or indirectly (i.e. derived from prices). • Level 3 – inputs for the asset or liability that are not based on observable market data. The Convertible Debentures are re-measured at fair value at each reporting date with any change in fair value recognized in profit or loss (Note 8). The Convertible Debentures are classified as Level 2. As at December 31, 2017, the Company’s risk exposures and the impact on the Company’s financial instruments are summarized below: (a) Credit Risk Credit risk is the risk that one party to a financial instrument will fail to discharge an obligation and cause the other party to incur a financial loss. Financial instruments potentially subject to credit risk are cash and cash equivalents and amounts receivable. The Company holds cash and cash equivalents with large Canadian and Australian banks. Credit risk is concentrated as a large portion of the Company’s cash and cash equivalents is held at one financial institution. Management believes the risk of loss to be remote. The Company’s amounts receivable consists of input tax credits receivable from the Government of Canada and interest accrued on cash equivalents. Accordingly, the Company does not believe it is subject to significant credit risk. (b) Liquidity Risk Liquidity risk is the risk that an entity will encounter difficulty in raising funds to meet commitments associated with financial instruments. The Company attempts to manage liquidity risk by maintaining sufficient cash and cash equivalent balances. Liquidity requirements are managed based on expected cash flows to ensure that there is sufficient capital to meet short-term obligations. The Company’s approach to managing liquidity risk is to ensure that it will have sufficient liquidity to meet liabilities when due. As at December 31, 2017, NexGen had cash and cash equivalents of $164,943,850 to settle accounts payable and accrued liabilities of $2,905,179. (c) Market Risk Market risk is the risk of loss that may arise from changes in market factors such as interest rates, foreign exchange rates and commodity and equity prices. (i) Interest Rate Risk Interest rate risk is the risk that the future cash flows of a financial instrument will fluctuate due to changes in market interest rates. The Company holds its cash and cash equivalents in bank accounts that earn variable interest rates. Due to the short-term nature of these financial instruments, fluctuations in market rates do not have a significant impact on the estimated fair value of the Company’s cash and cash equivalent balances as of December 31, 2017. The Company manages interest rate risk by maintaining an investment policy for short-term investments. This policy focuses primarily on preservation of capital and liquidity. The Company monitors the investments it makes and is satisfied with the credit rating of its banks. The Convertible Debentures, in an aggregate principal amount of US$120 million, carry a fixed interest rate of 7.5% and hence, are not subject to interest rate fluctuations. (ii) Foreign Currency Risk The functional currency of the Company and its subsidiaries is the Canadian dollar. The Company is affected by currency transaction risk and currency translation risk. Consequently, fluctuations of the Canadian dollar in relation to other currencies impact the fair value of financial assets, liabilities and operating results. Financial assets and liabilities subject to currency translation risk primarily include Australian and US dollar denominated cash and Australian and US dollar accounts payable and accrued liabilities. The Company maintains an Australian dollar bank account in Australia and Canadian and US dollar bank accounts in Canada. The Company is exposed to foreign exchange risk on its US dollar denominated Convertible Debentures. At maturity the US$120 million principal amount of the Convertible Debentures is due in full, and prior to then at a premium upon the occurrence of certain events, including a change of control. The Company holds sufficient US dollars to make all cash interest payments due under the Convertible Debentures until maturity but not to pay the principal amount. Accordingly, the Company is subject to risks associated with fluctuations in the Canadian/US dollar exchange rate that may make the Convertible Debentures more costly to repay. (iii) Price risk The Company is exposed to price risk with respect to commodity and equity prices. Equity price risk is defined as the potential adverse impact on the Company’s earnings due to movements in individual equity prices or general movements in the level of the stock market. Accordingly, significant movements in the Company’s share price may affect the valuation of the Convertible Debentures which may adversely impact its earnings. Commodity price risk is defined as the potential adverse impact on earnings and economic value due to commodity price movements and volatility. Future declines in commodity prices may impact the valuation of long-lived assets. The Company closely monitors commodity prices of uranium, individual equity movements, and the stock market to determine the appropriate course of action, if any, to be taken by the Company. Sensitivity Analysis As at December 31, 2017, the Company’s Australian dollar net financial assets were AUD $9,828 and its US dollar net financial liabilities were US$113,779,379. Thus a 10% change in the Canadian dollar versus the Australian and US dollar exchange rates would give rise to a $12,153,954 change in loss and comprehensive loss. The Company has not entered into any agreements or purchased any instruments to hedge possible currency risks at this time.

SEGMENT INFORMATION

SEGMENT INFORMATION	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
SEGMENT INFORMATION [Text Block]	13. SEGMENT INFORMATION The Company operates in one reportable segment, being the acquisition, exploration and development of uranium properties. All of the Company’s non-current assets are located in Canada.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
INCOME TAXES [Text Block]	14. INCOME TAXES A reconciliation of income taxes at statutory rates with the reported taxes is as follows: 2017 2016 Net loss for the year $ (56,863,922 ) $ (17,455,889 ) Statutory rate 26.75% 27.00% Expected income tax recovery $ (15,211,000 ) $ (4,713,000 ) Permanent differences 1,431,000 1,805,000 Impact of flow-through shares 580,000 480,000 Share issuance costs (1,276,000 ) - Adjustment to prior years provision versus statutory tax returns (597,000 ) 126,000 Change in unrecognized deductible temporary differences and other 15,040,000 2,378,000 Total $ (33,000 ) $ 76,000 The Company’s income tax (recovery) expense is comprised of the following: 2017 2016 Deferred income tax (recovery) expense $ (33,000 ) $ 76,000 Total $ (33,000 ) $ 76,000 The tax effects of temporary differences between amounts recorded in the Company’s accounts and the corresponding amounts as calculated for income tax purposes give rise to the following deferred tax (assets) and liabilities: 2017 2016 Exploration and evaluation assets $ 4,333,000 $ 3,532,000 Convertible debentures - 1,454,000 Non-capital losses (3,916,000 ) (4,004,000 ) Share issuance costs (119,000 ) (839,000 ) Equipment (18,000 ) (6,000 ) Net deferred tax liabilities $ 280,000 $ 137,000 Movement in the Company’s deferred tax liability balance in the year is as follows: 2017 2016 Opening balance $ 137,000 $ - Recognized in income tax expense 167,000 290,000 Recognized in equity (24,000 ) (153,000 ) Net deferred tax liability $ 280,000 $ 137,000 The significant components of the Company’s temporary differences, unused tax credits and unused tax losses that have not been included on the consolidated statement of financial position are as follows: Expiry Date Expiry Date 2017 Range 2016 Range Temporary Differences Non-capital losses available for future periods $ 24,735,000 2031 to 2037 $ - - Net capital losses 355,000 No expiry - - Share issuance costs 12,148,000 - 6,101,000 - Convertible debt 24,211,000 - - - Equipment 513,000 - 1,140,000 - Tax attributes are subject to review, and potential adjustment, by tax authorities.

NON-CONTROLLING INTERESTS

NON-CONTROLLING INTERESTS	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
NON-CONTROLLING INTERESTS [Text Block]	15. NON-CONTROLLING INTERESTS During the year ended December 31, 2016, the Company incorporated four new wholly owned subsidiaries in Canada and transferred certain exploration and evaluation assets to three of its wholly owned subsidiaries (Note 5). As at December 31, 2017, NexGen held 100% ownership of the subsidiaries with the exception of IsoEnergy, where it retained 63.9% of IsoEnergy’s outstanding common shares (Note 4(b)). NexGen received 29,000,000 common shares of IsoEnergy on the transfer of exploration assets to IsoEnergy. Subsequent to the transfer, common shares of IsoEnergy were issued to third parties as part of financings thereby resulting in the recognition of non- controlling interests. In June 2016, IsoEnergy issued 1,000,000 of its common shares for a 100% interest in the Thorburn North property. In August 2016, IsoEnergy accrued a liability of approximately $450,000 owing to NexGen, representing operational expenses financed by NexGen on behalf of IsoEnergy, which was converted into 450,000 common shares. A further 302,881 common shares of IsoEnergy were issued to an unrelated third party as part of a series of transactions relating to the listing of IsoEnergy on the TSX- V. During the year ended December 31, 2016, IsoEnergy issued 6,364,450 of its common shares and 3,934,636 of its flow- through common shares to unrelated third parties in exchange for gross proceeds of $10,692,550 and issued 8,580 of its common shares as a finder’s fee relating to the financings. During the year ended December 31, 2017, IsoEnergy issued 999,999 of its flow-through common shares to unrelated third parties in exchange for gross proceeds of $1,100,000. A further 3,000,000 and 1,000,000 of its common shares were issued for the acquisition of the Radio and Geiger properties, respectively. For financial reporting purposes, the assets, liabilities, results of operations, and cash flows of the Company’s wholly owned subsidiaries and non-wholly owned subsidiary, IsoEnergy, are included in NexGen’s consolidated financial statements. Third party investors’ share of the net earnings of IsoEnergy is reflected in the loss and comprehensive loss attributable to non-controlling interests in the consolidated statements of loss and comprehensive loss. Summarized financial information for subsidiaries with material non-controlling interests is as follows: 2017 2016 Cash and cash equivalents $ 3,325,000 $ 6,492,000 Other current assets 67,000 214,000 Non-current assets 39,124,000 33,086,000 Total assets $ 42,516,000 $ 39,792,000 Current liabilities 247,000 468,000 Non-current liabilities 281,000 137,000 Total liabilities $ 528,000 $ 605,000 Loss from operations $ 2,516,000 $ 2,255,000 Loss and comprehensive loss 2,462,000 2,470,000 Net cash flow from operating activities (1,536,000 ) (1,266,000 ) Net cash flow from investing activities (2,647,000 ) (2,825,000 ) Net cash flow from financing activities 1,017,000 10,583,000 Net increase (decrease) in cash and cash equivalents $ (3,166,000 ) $ 6,492,000

SUPPLEMENTAL DISCLOSURE WITH RE

SUPPLEMENTAL DISCLOSURE WITH RESPECT TO CASH FLOWS	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
SUPPLEMENTAL DISCLOSURE WITH RESPECT TO CASH FLOWS [Text Block]	16. SUPPLEMENTAL DISCLOSURE WITH RESPECT TO CASH FLOWS The significant non-cash transactions during the year ended December 31, 2017 included: a) At December 31, 2017, $612,900 of exploration and evaluation asset expenditures and $305,135 of equipment expenditures were included in accounts payable and accrued liabilities. b) At December 31, 2017, $689,976 of interest expense related to the Convertible Debentures was included in accounts payable and accrued liabilities. On June 12, 2017, the Company issued 327,863 common shares valued at $963,917 for the non-cash portion of the 2016 Debenture interest payment. On December 11, 2017, the Company issued 555,670 common shares valued at $1,955,958 for the non-cash portion of the 2016 Debenture and 2017 Debenture interest payment. c) Share-based payments of $3,309,791 was included in exploration and evaluation assets (Note 5). d) The re-allocation upon exercise of stock options from reserves to share capital of $853,100. e) The Company issued 111,110 common shares to acquire the remaining 40% interest in the Dufferin Lake property recorded at the estimated fair value of the common shares of $333,330. f) IsoEnergy issued an aggregate of 4,000,000 common shares for the acquisition of mineral properties recorded at the estimated fair value of the common shares of $3,040,000. The significant non-cash transactions during the year ended December 31, 2016 included: a) The re-allocation upon exercise of warrants from reserves to share capital of $934,361. b) At December 31, 2016, $535,444 of exploration and evaluation asset expenditures and $157,040 of equipment expenditures were included in accounts payable and accrued liabilities. c) Share-based payments of $3,036,207 was included in exploration and evaluation assets (Note 5). d) The re-allocation upon exercise of stock options from reserves to share capital of $726,574. e) IsoEnergy issued 1,000,000 of its common shares for the acquisition of a mineral property recorded at the estimated fair value of the common shares of $1,000,000. f) On December 12, 2016, the Company issued 521,115 common shares valued at $1,125,608 for the non-cash portion of the 2016 Debenture interest payment.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
SUBSEQUENT EVENTS [Text Block]	17. SUBSEQUENT EVENTS a) Subsequent to year-end, the Company issued 3,983,334 common shares on the exercise of 3,983,334 stock options at prices ranging from $0.40 to $1.51 for total proceeds of $1,975,334. b) On January 8, 2018, IsoEnergy granted 440,000 stock options at an exercise price of $0.57 per stock option. The options have a five-year life and vest one third annually with one third vesting immediately.

Summary of Significant Accounti

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
Functional and Presentation Currency [Policy Text Block]	(a) Functional and Presentation Currency These financial statements are presented in Canadian dollars, which is the functional currency of the Company and its subsidiaries. Translation of transactions and balances Foreign currency transactions are translated into the functional currency using the exchange rates prevailing at the dates of the transactions or valuation where items are re-measured. Monetary assets and liabilities denominated in foreign currencies are translated at the functional currency spot rate of exchange in effect at the reporting date. Non-monetary items that are measured in terms of historical cost in a foreign currency are translated using the exchange rate as at the date of the initial transaction. Translation gains or losses are recognized in profit or loss.
Consolidation [Policy Text Block]	(b) Consolidation These consolidated financial statements include the accounts of the Company and its subsidiaries: NXE Energy Royalty Ltd., NXE Energy SW1 Ltd., NXE Energy SW3 Ltd. and IsoEnergy. Shares of IsoEnergy were issued to third parties as part of financings since its inception, thereby resulting in the recognition of non-controlling interests. The financial results of the subsidiaries are included in these consolidated financial statements from the date of incorporation. Intercompany balances and transactions are eliminated on consolidation. The following table sets forth the Company’s ownership percentage in each of its subsidiaries as of December 31, 2017: Name of Subsidiary % Ownership as of December 31, 2017 NXE Energy Royalty Ltd. 100% NXE Energy SW1 Ltd. 100% NXE Energy SW3 Ltd. 100% IsoEnergy Ltd. 63.9%
Cash and cash equivalents [Policy Text Block]	(c) Cash and cash equivalents Cash and cash equivalents include deposits held with banks that are available on demand and guaranteed investment certificates with original maturities of three months or less or that are readily convertible into cash.
Exploration and evaluation assets [Policy Text Block]	(d) Exploration and evaluation assets Once the legal rights to explore a property have been obtained, exploration and evaluation costs are capitalized as exploration and evaluation assets on an area of interest basis pending determination of the technical feasibility and the commercial viability of the project. Capitalized costs include costs directly related to exploration and evaluation activities in the area of interest. When a claim is relinquished or a project is abandoned, the related costs are recognized in profit or loss immediately. Proceeds received from the sale of any interest in a property will be credited against the carrying value of the property, with any excess included in operations for the period. If a property is abandoned, the acquisition and deferred exploration costs will be written off to operations. Although the Company has taken steps to verify title to exploration and evaluation assets in which it has an interest, in accordance with industry standards for the current stage of exploration of such properties, these procedures do not guarantee the Company’s title. A property may be subject to unregistered prior agreements or inadvertent non-compliance with regulatory requirements. Management regularly assesses exploration and evaluation assets for events or circumstances that may indicate possible impairment. Once the technical feasibility and commercial viability of the extraction of mineral resources in an area of interest are demonstrable, exploration and evaluation assets attributable to that area of interest are first tested for impairment and then reclassified to mining assets and development assets within property, plant and equipment.
Equipment [Policy Text Block]	(e) Equipment (i) Recognition and measurement Items of equipment are stated at cost less accumulated depreciation and impairment losses. Cost includes expenditures that are directly attributable to the acquisition of the asset. (ii) Subsequent costs The cost of replacing a part of an item in the carrying amount of equipment is recognized when that cost is incurred, if it is probable that the future economic benefits embodied within the item will flow to the Company and the cost of the item can be measured reliably. (iii) Depreciation The carrying amounts of equipment (including initial and subsequent capital expenditures) are amortized to their estimated residual value over the estimated useful lives of the specific assets concerned. Depreciation is calculated over the estimated useful lives of each significant component as follows: - Computing equipment 55% declining balance basis - Software 55% declining balance basis - Field equipment 20% declining balance basis - Leasehold improvements 5 -year lease term - Road 5 -year straight-line basis Depreciation methods, useful lives, and residual values are reviewed at least annually and adjusted if appropriate. (iv) Disposal Gains and losses on disposal of an item of equipment are determined by comparing the proceeds from disposal with the carrying amount of the item of equipment and are recognized in profit or loss.
Impairment [Policy Text Block]	(f) Impairment An impairment loss is recognized when the carrying amount of an asset, or its cash generating unit (“CGU”), exceeds its recoverable amount. A CGU is the smallest identifiable group of assets that generates cash inflows that are largely independent of the cash inflows from other assets or groups of assets. Impairment losses are recognized in profit and loss for the period. Impairment losses recognized in respect of CGUs are allocated first to reduce the carrying amount of any goodwill allocated to CGUs and then to reduce the carrying amount of the other assets in the unit on a pro-rata basis. The recoverable amount of assets is the greater of an asset’s fair value less cost to sell and value in use. In assessing value in use, the estimated future cash flows are discounted to their present value using a pre-tax discount rate that reflects the current market assessments of the time value of money and the risks specific to the asset. For an asset that does not generate cash inflows largely independent of those from other assets, the recoverable amount is determined for the cash-generating unit to which the asset belongs. An impairment loss is only reversed if there is an indication that the impairment loss may no longer exist and there has been a change in the estimates used to determine the recoverable amount, however, not to an amount higher than the carrying amount that would have been determined had no impairment loss been recognized in previous years. Assets that have an indefinite useful life are not subject to depreciation and are tested annually for impairment.
Decommissioning and Restoration Provisions [Policy Text Block]	(g) Decommissioning and Restoration Provisions Decommissioning and restoration provisions are recorded when a present legal or constructive obligation exists as a result of past events where it is probable that an outflow of resources embodying economic benefits will be required to settle the obligation, and a reliable estimate of the amount of the obligation can be made. The amount recognized as a provision is the best estimate of the consideration required to settle the present obligation at the reporting date, taking into account the risks and uncertainties surrounding the obligation and discount rates. Where a provision is measured using the cash flows estimated to settle the present obligation, its carrying amount is the present value of those cash flows discounted for the market discount rate. Over time the discounted liability is increased for the changes in the present value based on the current market discount rates and liability risks. When some or all of the economic benefits required to settle a provision are expected to be recovered from a third party, the receivable is recognized as an asset if it is virtually certain that reimbursement will be received and the amount receivable can be measured reliably. Changes in reclamation estimates are accounted for prospectively as a change in the corresponding capitalized cost. The Company did not have any decommissioning and restoration provisions for the years presented.
Share Capital [Policy Text Block]	(h) Share Capital Common shares are classified as equity. Incremental costs directly attributable to the issue of common shares are recognized as a deduction from equity. Common shares issued for consideration other than cash, are valued based on their market value at the date the shares are issued. The Company has adopted a residual value method with respect to the measurement of shares and warrants issued as private placement units. The residual value method first allocates value to the more easily measurable component based on fair value and then the residual value, if any, to the less easily measurable component. The Company considers the fair value of common shares issued in the private placements to be the more easily measurable component and the common shares are valued at their fair value, as determined by the closing market price on the announcement date. The balance, if any, is allocated to the attached warrants. Any fair value attributed to the warrants is recorded as reserves.
Share-based payments [Policy Text Block]	(i) Share-based payments The Company’s stock option plan allows Company employees, directors, officers and consultants to acquire shares of the Company. The fair value of options granted is recognized as share-based payments expense with a corresponding increase in equity reserves. The fair value of the options granted is measured using the Black-Scholes option pricing model, taking into account the terms and conditions upon which the options were granted. Fair value is measured at grant date, and each tranche is recognized using the graded vesting method over the period during which the options vest. At each financial reporting date, the amount recognized as an expense is adjusted to reflect the actual number of stock options that are expected to vest. In situations where equity instruments are issued to non-employees and some or all of the goods or services received by the entity as consideration cannot be specifically identified, they are measured at the fair value of the share-based payment. Share-based payment awards to non-employees are measured at the fair value of goods or services received. An individual is classified as an employee when the individual is an employee for legal or tax purposes (direct employee) or provides services similar to those performed by a direct employee.
Flow-through shares [Policy Text Block]	(j) Flow-through shares Resource expenditure deductions for income tax purposes related to exploration activities funded by flow-through share arrangements are renounced to investors under Canadian income tax legislation. On issuance, the Company separates the flow-through share into i) a flow-through share premium, equal to the estimated premium, if any, investors pay for the flow- through feature, which is recognized as a liability and ii) share capital. Upon qualifying expenditures being incurred, the Company recognizes a deferred tax liability for the taxable temporary difference that arises from the difference between the carrying amount of eligible expenditures capitalized as exploration and evaluation assets and its tax base and the premium is recognized as a reduction of deferred tax expense. Proceeds received from the issuance of flow-through shares must be expended on Canadian resource property exploration within a period of two years. Failure to expend such funds as required under the Canadian income tax legislation will result in a Part XII.6 tax to the Company on flow-through proceeds renounced under the “Look-back” Rule. When applicable, this tax is accrued as a financial expense until paid.
Financial Instruments [Policy Text Block]	(k) Financial Instruments The Company classifies its financial assets into one of the following categories as follows: Fair value through profit or loss (“FVTPL”) - Loans and receivables Held-to-maturity investments - Available-for-sale All financial assets except those measured at fair value through profit or loss are subject to review for impairment at least at each reporting date. Financial assets are impaired when there is objective evidence of impairment as a result of one or more events that have occurred after initial recognition of the asset and that event has an impact on the estimated future cash flows of the financial asset or the group of financial assets. Financial liabilities The Company classifies its financial liabilities into one of two categories as follows: Fair value through profit or loss (FVTPL) Other financial liabilities -
Loss per Share [Policy Text Block]	(l) Loss per Share Basic loss per share is calculated by dividing the loss for the year by the weighted average number of common shares outstanding during the year. The Company uses the treasury stock method to compute the dilutive effect of options, warrants and other similar instruments. Under this method, the weighted average number of shares outstanding used in the calculation of diluted loss per share assumes that the deemed proceeds received from the exercise of stock options, share purchase warrants and their equivalents would be used to repurchase common shares of the Company at the average market price during the period. Existing stock options and share purchase warrants have not been included in the computation of diluted loss per share as to do so would be anti-dilutive. Accordingly, basic and diluted loss per share is the same for the years presented.
Income taxes [Policy Text Block]	(m) Income taxes Income tax expense comprises current and deferred tax. Current tax and deferred tax are recognized in profit or loss except to the extent that it relates to items recognized directly in equity or in other comprehensive income. Current tax is the expected tax payable or receivable on the taxable income or loss for the year, using tax rates enacted at the reporting date, and any adjustment to tax payable in respect of previous years. Deferred tax is recognized in respect of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for taxation purposes. Deferred tax is not recognized for the following temporary differences: the initial recognition of assets or liabilities in a transaction that is not a business combination and that affects neither accounting nor taxable profit or loss, and differences relating to investments in subsidiaries and jointly controlled entities to the extent that it is probable that they will not reverse in the foreseeable future. In addition, deferred tax is not recognized for taxable temporary differences arising on the initial recognition of goodwill. Deferred tax is measured at the tax rates that are expected to be applied to temporary differences when they reverse, based on the laws that have been enacted or substantively enacted by the reporting date. Deferred tax assets and liabilities are offset if there is a legally enforceable right to offset current tax liabilities and assets, and they relate to income taxes levied by the same tax authority on the same taxable entity, or on different tax entities, but they intend to settle current tax liabilities and assets on a net basis or their tax assets and liabilities will be realized simultaneously. A deferred tax asset is recognized for unused tax losses, tax credits and deductible temporary differences, to the extent that it is probable that future taxable profits will be available against which they can be utilized. Deferred tax assets are reviewed at each reporting date and are reduced to the extent that it is no longer probable that the related tax benefit will be realized. Change in accounting policy: In the prior year, the proceeds allocated to the flow-through share premium was recognized as “income on reduction of flow-through premium liability” in the consolidated statements of loss and comprehensive loss over the period that the flow-through proceeds were spent on eligible exploration expenditures. Commencing January 1, 2017, this premium is measured on the same basis, however, it is recorded as a deferred tax benefit. The Company voluntarily changed this classification with a view to better present the results of the Company. The impact on the statement of loss and comprehensive loss and statement of cash flows for the year ended December 31, 2016 is a $214,252 reclassification from income on reduction of flow-through premium liability to a reduction of deferred income tax expense. There was no impact on loss and comprehensive loss for 2016, total assets or total shareholders’ equity as at December 31, 2016. Future accounting pronouncements: The following standards have not been adopted by the Company and are being evaluated to determine their impact: • IFRS 9: New standard that replaced IAS 39 for classification and measurement of financial instruments, effective for annual periods beginning on or after January 1, 2018. There are no material differences expected as a result of adopting the new standard. • IFRS 16: New standard that will replace IAS 17 for the accounting and measurement of leases with a term of more than 12 months, effective for annual periods beginning on or after January 1, 2019. The Company does not expect the standard to have a material impact on its financial statements based on the leases in place at December 31, 2017. • IFRS 2: This standard was amended to clarify how to account for certain types of share-based payment transactions, effective for annual periods beginning on or after January 1, 2018. The amendments provide for the accounting of vesting and non-vesting conditions on the measurement of cash-settled share-based payments, share-based payment transactions with a net settlement feature for withholding tax obligations, and a modification to the terms and conditions of a share-based payment that changes the classification of the transaction from cash-settled to equity-settled. The extent of the impact of adoption of the amended standard has not yet been determined.

SIGNIFICANT ACCOUNTING POLICI24

SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
Disclosure of subsidiaries [Table Text Block]	Name of Subsidiary % Ownership as of December 31, 2017 NXE Energy Royalty Ltd. 100% NXE Energy SW1 Ltd. 100% NXE Energy SW3 Ltd. 100% IsoEnergy Ltd. 63.9%
Disclosure of detailed information about estimated useful life or depreciation rate [Table Text Block]	- Computing equipment 55% declining balance basis - Software 55% declining balance basis - Field equipment 20% declining balance basis - Leasehold improvements 5 -year lease term - Road 5 -year straight-line basis

EXPLORATION AND EVALUATION AS25

EXPLORATION AND EVALUATION ASSETS (Tables)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Statement [Line Items]
Disclosure of detailed information about exploration and evaluation assets [Table Text Block]	Rook 1 Other Athabasca Properties IsoEnergy Properties Total $ $ $ $ Acquisition costs: Balance, December 31, 2016 $ 230,807 $ 1,124,277 $ 21,438,306 22,793,390 Additions 4,270 333,330 3,298,942 3,636,542 Balance, December 31, 2017 $ 235,077 $ 1,457,607 $ 24,737,248 26,429,932 Deferred exploration costs: Balance, December 31, 2016 $ 77,007,303 $ 4,318,909 $ 5,327,318 $ 86,653,530 Additions: Drilling 20,592,799 3,297 1,168,096 21,764,192 General exploration 2,163,554 25,885 110,603 2,300,042 Geological and geophysical 5,206,266 681,955 521,632 6,409,853 Labour and wages 4,391,456 - 510,398 4,901,854 Share-based payments (Note 9) 2,952,316 - 357,475 3,309,791 Travel 624,265 - 106,845 731,110 35,930,656 711,137 2,775,049 39,416,842 Impairment - (87,749 ) - (87,749 ) Balance, December 31, 2017 $ 112,937,959 $ 4,942,297 $ 8,102,367 $ 125,982,623 Total costs, December 31, 2017 $ 113,173,036 $ 6,399,904 $ 32,839,615 $ 152,412,555	Rook 1 Other Athabasca Properties IsoEnergy Properties Radio Total $ $ $ $ $ Acquisition costs: Balance, December 31, 2015 $ 220,713 1,274,966 - 20,133,753 21,629,432 Additions 10,094 53,864 1,100,000 - 1,163,958 Properties transferred to IsoEnergy - (204,553 ) 20,338,306 (20,133,753 ) - Balance, December 31, 2016 $ 230,807 1,124,277 21,438,306 - 22,793,390 Deferred exploration costs: Balance, December 31, 2015 $ 37,803,918 3,409,339 - 2,293,824 43,507,081 Additions: Drilling 24,989,860 16,061 1,197,163 - 26,203,084 General exploration 2,283,418 8,873 119,460 - 2,411,751 Geological and geophysical 5,333,676 1,991,174 882,866 - 8,207,716 Labour and wages 3,542,893 - 363,420 - 3,906,313 Share-based payments (Note 9) 2,779,787 - 256,420 - 3,036,207 Travel 273,751 - 72,485 - 346,236 39,203,385 2,016,108 2,891,814 - 44,111,307 Properties transferred to IsoEnergy - (141,680 ) 2,435,504 (2,293,824 ) - Impairment - (964,858 ) - - (964,858 ) Balance, December 31, 2016 $ 77,007,303 4,318,909 5,327,318 - 86,653,530 Total costs, December 31, 2016 $ 77,238,110 5,443,186 26,765,624 - 109,446,920

COMMITMENTS (Tables)

COMMITMENTS (Tables)	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
Disclosure of detailed information about flow-through share premium liability [Table Text Block]	Year ended Year ended December 31, 2017 December 31, 2016 Balance, beginning of the year $ 179,212 $ - Liability incurred on flow-through shares issued 130,000 393,464 Settlement of flow-through share liability on expenditure made (199,961 ) (214,252 ) Balance, end of the year $ 109,251 $ 179,212
Disclosure of leases [Table Text Block]	2018 $ 360,975 2019 $ 325,294 2020 $ 199,466

EQUIPMENT (Tables)

EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
Disclosure of detailed information about equipment [Table Text Block]	Computing Equipment Software Field Equipment Leasehold Improvements Road Total Cost Balance at December 31, 2015 $ 65,490 $ 95,926 $ 1,237,013 $ 183,034 $ - $ 1,581,463 Additions 44,158 184,044 1,519,627 32,138 1,282,890 3,062,857 Balance at December 31, 2016 109,648 279,970 2,756,640 215,172 1,282,890 4,644,320 Additions 125,938 98,763 1,490,880 - 490,695 2,206,276 Disposals - - (29,300 ) - - (29,300 ) Balance at December 31, 2017 $ 235,586 $ 378,733 $ 4,218,220 $ 215,172 $ 1,773,585 $ 6,821,296 Accumulated Depreciation Balance at December 31, 2015 $ 42,259 $ 40,458 $ 305,114 $ 6,101 $ - $ 393,932 Depreciation 24,920 81,119 338,343 41,743 163,085 649,210 Balance at December 31, 2016 67,179 121,577 643,457 47,844 163,085 1,043,142 Depreciation 60,744 114,367 482,738 42,686 98,940 799,475 Disposals - - (4,395 ) - - (4,395 ) Balance at December 31, 2017 $ 127,923 $ 235,944 $ 1,121,800 $ 90,530 $ 262,025 $ 1,838,222 Net book value: At December 31, 2016 $ 42,469 158,393 $ 2,113,183 $ 167,328 $ 1,119,805 $ 3,601,178 At Dectember 31, 2017 $ 107,663 $ 142,789 $ 3,096,420 $ 124,642 $ 1,511,560 $ 4,983,074

CONVERTIBLE DEBENTURES (Tables)

CONVERTIBLE DEBENTURES (Tables)	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
Disclosure of detailed information about convertible debentures [Table Text Block]	December 31, 2017 December 31, 2016 2016 Debentures (a) $ 90,742,373 $ 70,811,801 2017 Debentures (b) 80,627,593 - Convertible Debentures $ 171,369,966 $ 70,811,801
2016 Debentures [Member]
Statement [Line Items]
Disclosure of detailed information about convertible debentures, fair value and interest components [Table Text Block]	December 31, 2017 December 31, 2016 Fair value of 2016 Debentures, beginning of period $ 70,811,801 $ 74,123,520 Fair value adjustment to December 31, 2017 19,930,572 (3,311,719 ) Interest payable 350,900 369,243 2016 Debentures and interest payable 91,093,273 $ 71,181,044 Less: interest payable included in accounts payable & accrued liabilities (350,900 ) (369,243 ) 2016 Debentures $ 90,742,373 $ 70,811,801
Disclosure of detailed information about convertible debentures, valuation assumptions [Table Text Block]	December 31, 2017 December 31, 2016 Volatility 39.00% 40.00% Expected life in years 4.56 years 4.44 years Risk free interest rate 2.23% 1.91% Expected dividend yield 0% 0% Credit spread 25.35% 26.44% Underlying share price of the Company $ 3.21 $ 2.33 Conversion exercise price US$2.3261 US$2.3261 Exchange rate (C$:US$) $ 0.7971 $ 0.7448
2017 Debentures [Member]
Statement [Line Items]
Disclosure of detailed information about convertible debentures, fair value and interest components [Table Text Block]	December 31, 2017 Fair value of 2017 Debentures on issuance $ 73,035,180 Fair value adjustment to December 31, 2017 7,592,413 Interest payable 350,900 2017 Debentures and interest payable 80,978,493 Less: interest payable included in accounts payable & accrued liabilities (350,900 ) 2017 Debentures $ 80,627,593
Disclosure of detailed information about convertible debentures, valuation assumptions [Table Text Block]	December 31, 2017 July 21, 2017 Volatility 39.00% 38.00% Expected life in years 4.56 years 5.00 years Risk free interest rate 2.23% 1.88% Expected dividend yield 0% 0% Credit spread 25.35% 25.35% Underlying share price of the Company $ 3.21 $ 3.04 Conversion exercise price US$2.6919 US$2.6919 Exchange rate (C$:US$) $ 0.7971 $ 0.7969

SHARE CAPITAL AND RESERVES (Tab

SHARE CAPITAL AND RESERVES (Tables)	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
Disclosure of detailed information about warrants, activity [Table Text Block]	Number of Weighted Average Warrants Exercise Price Outstanding at December 31, 2015 19,918,592 $ 0.59 Exercised (14,787,443 ) 0.63 Issued on exercise of broker warrants 614,137 0.65 Expired (31,000 ) 0.65 Outstanding at December 31, 2016 5,714,286 0.50 Exercised (5,714,286 ) 0.50 Outstanding at December 31, 2017 - $ -
Disclosure of number and weighted average exercise prices of share options [Table Text Block]	Weighted Number of Average Stock Options Exercise Price Outstanding at December 31, 2015 27,124,446 $ 0.48 Granted 10,200,000 2.45 Exercised (2,941,666 ) 0.41 Expired (116,667 ) 2.65 Forfeited (800,001 ) 1.36 Outstanding at December 31, 2016 33,466,112 $ 1.06 Granted 6,200,000 3.27 Exercised (1,424,445 ) 0.79 Forfeited (383,333 ) 2.53 Outstanding at December 31, 2017 37,858,334 $ 1.42 Number of options exercisable 30,783,334 $ 1.07
Disclosure of number and weighted average remaining contractual life of outstanding share options [Table Text Block]	Remaining Number of Number Exercise Contractual Options Exercisable Price Life (Years) Expiry Date 3,600,000 3,600,000 $ 0.400 0.08 January 31, 2018 333,334 333,334 $ 1.510 0.19 March 12, 2018 1,450,000 1,450,000 $ 0.400 0.58 July 30, 2018 250,000 250,000 $ 0.300 0.97 December 19, 2018 2,625,000 2,625,000 $ 0.400 1.39 May 23, 2019 750,000 750,000 $ 0.400 1.42 June 2, 2019 4,550,000 4,550,000 $ 0.460 1.98 December 24, 2019 4,200,000 4,200,000 $ 0.500 2.41 May 27, 2020 500,000 500,000 $ 0.620 2.73 September 22, 2020 4,575,000 4,575,000 $ 0.640 2.96 December 16, 2020 250,000 166,667 $ 2.690 3.44 June 8, 2021 5,275,000 3,516,666 $ 2.650 3.48 June 23, 2021 3,300,000 2,200,000 $ 2.240 3.96 December 15, 2021 150,000 50,000 $ 3.300 4.05 January 19, 2022 250,000 83,334 $ 3.110 4.31 April 22, 2022 1,475,000 491,666 $ 2.930 4.87 November 13, 2022 4,325,000 1,441,667 $ 3.390 4.96 December 14, 2022 37,858,334 30,783,334
Disclosure of detailed information about options, valuation assumptions [Table Text Block]	December 31, December 31, 2017 2016 Expected stock price volatility 81.72% 87.15% Expected life of options 5.00 years 5.00 years Risk free interest rate 1.53% 0.68% Expected forfeitures 0% 0% Expected dividend yield 0% 0% Weighted average fair value per option granted in the year $ 2.13 $ 1.65
Disclosure of reserves within equity [Table Text Block]	Total Balance, December 31, 2015 $ 7,530,180 Exercise of options (726,574 ) Exercise of warrants (934,361 ) Share-based payments 11,136,420 Balance, December 31, 2016 $ 17,005,665 Exercise of options (853,100 ) Expired warrants adjustment (595,964 ) Share-based payments 12,493,458 Balance, December 31, 2017 $ 28,050,059

RELATED PARTY TRANSACTIONS (Tab

RELATED PARTY TRANSACTIONS (Tables)	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
Disclosure of information about key management personnel [Table Text Block]	For the years ended December 31, 2017 December 31, 2016 Short-term compensation (1) $ 4,101,441 $ 3,189,845 Share-based payments (stock options) (2) 8,830,606 7,686,442 $ 12,932,047 $ 10,876,287

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
Disclosure of detailed information about effective income tax expense recovery [Table Text Block]	2017 2016 Net loss for the year $ (56,863,922 ) $ (17,455,889 ) Statutory rate 26.75% 27.00% Expected income tax recovery $ (15,211,000 ) $ (4,713,000 ) Permanent differences 1,431,000 1,805,000 Impact of flow-through shares 580,000 480,000 Share issuance costs (1,276,000 ) - Adjustment to prior years provision versus statutory tax returns (597,000 ) 126,000 Change in unrecognized deductible temporary differences and other 15,040,000 2,378,000 Total $ (33,000 ) $ 76,000
Disclosure of deferred taxes [Table Text Block]	2017 2016 Deferred income tax (recovery) expense $ (33,000 ) $ 76,000 Total $ (33,000 ) $ 76,000
Disclosure of deferred tax liabilities [Table Text Block]	2017 2016 Exploration and evaluation assets $ 4,333,000 $ 3,532,000 Convertible debentures - 1,454,000 Non-capital losses (3,916,000 ) (4,004,000 ) Share issuance costs (119,000 ) (839,000 ) Equipment (18,000 ) (6,000 ) Net deferred tax liabilities $ 280,000 $ 137,000
Disclosure of detailed information about deferred tax liabilities [Table Text Block]	2017 2016 Opening balance $ 137,000 $ - Recognized in income tax expense 167,000 290,000 Recognized in equity (24,000 ) (153,000 ) Net deferred tax liability $ 280,000 $ 137,000
Disclosure of temporary difference, unused tax losses and unused tax credits [Table Text Block]	Expiry Date Expiry Date 2017 Range 2016 Range Temporary Differences Non-capital losses available for future periods $ 24,735,000 2031 to 2037 $ - - Net capital losses 355,000 No expiry - - Share issuance costs 12,148,000 - 6,101,000 - Convertible debt 24,211,000 - - - Equipment 513,000 - 1,140,000 -

NON-CONTROLLING INTERESTS (Tabl

NON-CONTROLLING INTERESTS (Tables)	12 Months Ended
	Dec. 31, 2017
Statement [Line Items]
Disclosure of summarized financial information for subsidiaries with material non-controlling interests [Table Text Block]	2017 2016 Cash and cash equivalents $ 3,325,000 $ 6,492,000 Other current assets 67,000 214,000 Non-current assets 39,124,000 33,086,000 Total assets $ 42,516,000 $ 39,792,000 Current liabilities 247,000 468,000 Non-current liabilities 281,000 137,000 Total liabilities $ 528,000 $ 605,000 Loss from operations $ 2,516,000 $ 2,255,000 Loss and comprehensive loss 2,462,000 2,470,000 Net cash flow from operating activities (1,536,000 ) (1,266,000 ) Net cash flow from investing activities (2,647,000 ) (2,825,000 ) Net cash flow from financing activities 1,017,000 10,583,000 Net increase (decrease) in cash and cash equivalents $ (3,166,000 ) $ 6,492,000

REPORTING ENTITY (Narrative) (D

REPORTING ENTITY (Narrative) (Details)	12 Months Ended
	Dec. 31, 2017
IsoEnergy Ltd. [Member]
Statement [Line Items]
Proportion of ownership interest in subsidiary	63.90%

NATURE OF OPERATIONS (Narrative

NATURE OF OPERATIONS (Narrative) (Details) - CAD	Dec. 31, 2017	Dec. 31, 2016
Statement [Line Items]
Accumulated deficit	CAD 88,038,390	CAD 32,743,616
Working capital	CAD 162,745,615

SIGNIFICANT ACCOUNTING POLICI35

SIGNIFICANT ACCOUNTING POLICIES (Narrative) (Details)	12 Months Ended
	Dec. 31, 2016CAD
Statement [Line Items]
Impact of change in accounting policy	CAD 214,252

EXPLORATION AND EVALUATION AS36

EXPLORATION AND EVALUATION ASSETS (Narrative) (Details)	12 Months Ended
	Dec. 31, 2017CADha	Dec. 31, 2016CAD
Statement [Line Items]
Impairment of exploration and evaluation assets	CAD 87,749	CAD 964,858
Rook 1 Property [Member]
Statement [Line Items]
Number of mineral claims	32
Size of mineral property | ha	35,065
Ownership percentage of mineral property	100.00%
Net smelter return royalty	2.00%
Production carried interest	10.00%
Details about net smelter return royalty	The NSR may be reduced to 1% upon payment of $1 million.
Other Athabasca Basin Properties [Member]
Statement [Line Items]
Impairment of exploration and evaluation assets	CAD 87,749	CAD 964,858
IsoEnergy Ltd. [Member] | Radio property [Member]
Statement [Line Items]
Ownership percentage of mineral property	100.00%
Net smelter return royalty	2.00%
Details about net smelter return royalty	subject to a 2% net smelter return royalty and 2% gross overriding royalty
IsoEnergy Ltd. [Member] | Thorburn Lake property [Member]
Statement [Line Items]
Ownership percentage of mineral property	100.00%
Net smelter return royalty	1.00%
Production carried interest	10.00%
Details about net smelter return royalty	subject to a 1% net smelter return royalty and a 10% carried interest which can be reduced to 1% at the holder’s option upon completion of a bankable feasibility study
IsoEnergy Ltd. [Member] | Madison, 2Z, Carlson Creek and North Thorburn properties [Member]
Statement [Line Items]
Ownership percentage of mineral property	100.00%
IsoEnergy Ltd. [Member] | Mountain Lake property [Member]
Statement [Line Items]
Ownership percentage of mineral property	100.00%
IsoEnergy Ltd. [Member] | Geiger property [Member]
Statement [Line Items]
Ownership percentage of mineral property	100.00%

COMMITMENTS (Narrative) (Detail

COMMITMENTS (Narrative) (Details) - CAD	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2016
Statement [Line Items]
Proceeds from issue of flow-through shares	CAD 1,100,000
Deposits	32,927		CAD 22,852
Office lease - Vancouver [Member]
Statement [Line Items]
Deposits	17,400
Office lease - Saskatoon [Member]
Statement [Line Items]
Deposits	10,075
IsoEnergy Ltd. [Member]
Statement [Line Items]
Required exploration expenditures		CAD 900,000
IsoEnergy Ltd. [Member] | Office lease [Member]
Statement [Line Items]
Deposits	CAD 5,452

CONVERTIBLE DEBENTURES (Narrati

CONVERTIBLE DEBENTURES (Narrative) (Details)	Jun. 10, 2016CADshares	Jun. 10, 2016USD ($)shares	Jul. 21, 2017CADshares	Jul. 21, 2017USD ($)shares	Dec. 31, 2017CAD	Dec. 31, 2017USD ($)	Dec. 31, 2016CAD	Dec. 31, 2017USD ($)	Jul. 21, 2017USD ($)	Dec. 31, 2016USD ($)	Jun. 10, 2016USD ($)
Statement [Line Items]
Convertible debenture issuance costs | CAD					CAD 2,811,146		CAD 4,052,398
Establishment fee, percent	3.00%	3.00%	3.00%	3.00%
Gains (losses) recognised in profit or loss, fair value measurement, liabilities					CAD 27,522,985	$ 21,938,571
Borrowings, interest rate					7.50%			7.50%
Borrowings, interest rate, payable in cash					5.00%			5.00%
Borrowings, interest rate, payable in common shares					2.50%			2.50%
2016 Debentures [Member]
Statement [Line Items]
Gross proceeds from issuance of convertible debentures	CAD 76,416,000	$ 60,000,000
Net proceeds from issuances of convertible debentures	72,363,602	56,852,383
Convertible debenture issuance costs	CAD 4,052,398	$ 3,147,617
Establishment fee, percent	3.00%	3.00%
Establishment fee	CAD 2,292,480	$ 1,800,000
Establishment fee (shares) | shares	1,005,586	1,005,586
Convertible debentures at fair value	CAD 74,123,520				CAD 90,742,373		CAD 70,811,801	$ 72,333,498		$ 52,738,364	$ 58,200,000
Gains (losses) recognised in profit or loss, fair value measurement, liabilities					CAD 19,930,572	$ 15,887,264
Borrowings, maturity					4.56 years	4.56 years	4.44 years
Convertible debt, conversion price | $								2.3261		$ 2.3261
2017 Debentures [Member]
Statement [Line Items]
Gross proceeds from issuance of convertible debentures			CAD 75,294,000	$ 60,000,000
Net proceeds from issuances of convertible debentures			72,482,854	57,759,864
Convertible debenture issuance costs			CAD 2,811,146	$ 2,240,136
Establishment fee, percent			3.00%	3.00%
Establishment fee			CAD 2,258,820	$ 1,800,000
Establishment fee (shares) | shares			869,271	869,271
Convertible debentures at fair value			CAD 73,035,180		CAD 80,627,593			64,270,700	$ 58,200,000
Gains (losses) recognised in profit or loss, fair value measurement, liabilities					CAD 7,592,413	$ 6,052,143
Borrowings, maturity			5.00 years	5.00 years	4.56 years	4.56 years
Borrowings, interest rate			7.50%						7.50%
Convertible debt, conversion price | $								$ 2.6919	$ 2.6919

SHARE CAPITAL AND RESERVES (Nar

SHARE CAPITAL AND RESERVES (Narrative) (Details)

Dec. 12, 2017CADshares

Dec. 11, 2017CADshares

Jun. 12, 2017CADshares

Dec. 12, 2016CADshares

Jun. 10, 2016CADshares

Feb. 12, 2016CADshares

Feb. 11, 2016CADshares

Jan. 12, 2016CADshares

Sep. 18, 2017CADshares

Jul. 21, 2017CADshares

Jul. 21, 2017USD ($)shares

May 31, 2017CADshares

Feb. 26, 2016CADshares

Dec. 31, 2016CADshares

Sep. 30, 2016CADshares

Jun. 30, 2016CADshares

Mar. 31, 2016CADshares

Dec. 31, 2017CADshares

Dec. 31, 2016CADshares

Statement [Line Items]

Exercise of options (shares) | shares

1,766,666

875,000

110,000

190,000

1,424,445

2,941,666

Weighted average exercise price of share options exercised in share-based payment arrangement

CAD 0.79

CAD 0.41

Proceeds from exercise of options

CAD 733,560

CAD 355,500

CAD 45,500

CAD 82,500

1,128,032

Exercise of options

CAD (1,128,032)

CAD (1,217,060)

Exercise of warrants (shares) | shares

153,534

460,602

5,714,286

5,714,286

14,787,443

Weighted average exercise price of warrants exercised in share-based payment arrangement

CAD 0.65

CAD 0.65

CAD 0.50

CAD 0.50

CAD 0.63

Proceeds from exercise of warrants

CAD 99,796

299,391

CAD 2,857,143

Exercise of warrants

CAD (2,857,143)

CAD (9,366,182)

Issue of shares on convertible debenture interest payment (shares) | shares

555,670

555,670

327,863

521,115

883,533

521,115

Issue of shares on convertible debenture interest payment

CAD 1,955,959

CAD 1,955,958

CAD 963,917

CAD 1,125,608

CAD 2,919,876

CAD 1,125,608

Issue of shares for cash from private placement (shares) | shares

24,146,424

24,146,424

24,146,424

Issue of shares for cash from private placement, share price | $

$ 2.0707

Shares issued for cash from private placements

CAD 62,745,000

$ 50,000,000

CAD 60,225,368

CAD 0

Issue of shares on convertible debenture financing (shares) | shares

1,005,586

869,271

869,271

869,271

1,005,586

Issue of shares on convertible debenture financing

CAD 2,292,480

CAD 2,258,820

CAD 2,258,820

CAD 2,292,480

Establishment fee, percent

3.00%

3.00%

3.00%

Share issue related cost

CAD 2,513,028

CAD 2,519,632

CAD 12

Issue of shares for exploration and evaluation assets (shares) | shares

111,110

49,861

Issue of shares for exploration and evaluation assets

CAD 333,330

CAD 48,864

Issue of shares on exercise of broker warrants | shares

921,204

Issue of warrants on exercise of broker warrants

460,602

Broker warrants exercised

921,204

Weighted average exercise price of broker warrants exercised in share-based payment arrangement

CAD 0.45

Proceeds from exercise of broker warrants

CAD 414,542

Description of maximum term of options granted for share-based payment arrangement

Pursuant to the Company’s stock option plan, directors may, from time to time, authorize the issuance of options to directors, officers, employees and consultants of the Company, enabling them to acquire up to 20% of the issued and outstanding common shares of the Company.The options can be granted for a maximum term of 10 years and are subject to vesting provisions as determined by the Board of Directors of the Company.

Share-based payments

CAD 12,493,458

11,136,420

Included in exploration and evaluation assets [Member]

Statement [Line Items]

Share-based payments

3,309,791

3,036,207

Expensed to the statement of loss (profit) and comprehensive loss (profit) [Member]

Statement [Line Items]

Share-based payments

CAD 9,183,667

8,100,213

Dufferin Lake property [Member]

Statement [Line Items]

Share issue related cost

CAD 6,604

Issue of shares for exploration and evaluation assets (shares) | shares

111,110

111,110

Issue of shares for exploration and evaluation assets

CAD 333,330

CAD 333,330

Increase in ownership interest due to issuances of shares

40.00%

40.00%

Other Athabasca Basin Properties [Member]

Statement [Line Items]

Issue of shares for exploration and evaluation assets (shares) | shares

49,861

Issue of shares for exploration and evaluation assets

CAD 48,864

Reserves [Member]

Statement [Line Items]

Exercise of options

CAD 440,721

CAD 223,607

CAD 21,306

CAD 40,940

CAD 853,100

726,574

Exercise of warrants

CAD 221,089

934,361

Share-based payments

CAD 12,493,458

CAD 11,136,420

Options exercised 1 [Member]

Statement [Line Items]

Exercise of options (shares) | shares

131,914

800,000

60,000

140,000

199,446

Weighted average exercise price of share options exercised in share-based payment arrangement

CAD 0.24

CAD 0.40

CAD 0.425

CAD 0.425

CAD 0.24

Options exercised 2 [Member]

Statement [Line Items]

Exercise of options (shares) | shares

1,218,086

50,000

50,000

50,000

100,000

Weighted average exercise price of share options exercised in share-based payment arrangement

CAD 0.40

CAD 0.46

CAD 0.40

CAD 0.46

CAD 0.40

Options exercised 3 [Member]

Statement [Line Items]

Exercise of options (shares) | shares

133,333

25,000

50,000

Weighted average exercise price of share options exercised in share-based payment arrangement

CAD 0.46

CAD 0.50

CAD 0.425

Options exercised 4 [Member]

Statement [Line Items]

Exercise of options (shares) | shares

200,000

200,000

Weighted average exercise price of share options exercised in share-based payment arrangement

CAD 0.50

CAD 0.46

Options exercised 5 [Member]

Statement [Line Items]

Exercise of options (shares) | shares

83,333

300,000

Weighted average exercise price of share options exercised in share-based payment arrangement

CAD 0.64

CAD 0.50

Options exercised 6 [Member]

Statement [Line Items]

Exercise of options (shares) | shares

83,333

Weighted average exercise price of share options exercised in share-based payment arrangement

CAD 0.62

Options exercised 7 [Member]

Statement [Line Items]

Exercise of options (shares) | shares

250,000

Weighted average exercise price of share options exercised in share-based payment arrangement

CAD 0.64

Options exercised 8 [Member]

Statement [Line Items]

Exercise of options (shares) | shares

16,667

Weighted average exercise price of share options exercised in share-based payment arrangement

CAD 2.24

Options exercised 9 [Member]

Statement [Line Items]

Exercise of options (shares) | shares

58,333

Weighted average exercise price of share options exercised in share-based payment arrangement

CAD 2.65

Options exercised 10 [Member]

Statement [Line Items]

Exercise of options (shares) | shares

166,666

Weighted average exercise price of share options exercised in share-based payment arrangement

CAD 2.24

Warrants exercised 1 [Member]

Statement [Line Items]

Exercise of warrants (shares) | shares

460,603

Weighted average exercise price of warrants exercised in share-based payment arrangement

CAD 0.65

Proceeds from exercise of warrants

CAD 237,978

Broker warrants exercised

307,069

Weighted average exercise price of broker warrants exercised in share-based payment arrangement

CAD 0.45

Warrants exercised 1 [Member] | Reserves [Member]

Statement [Line Items]

Exercise of warrants

CAD 73,697

Warrants exercised 1 - non-broker warrants [Member]

Statement [Line Items]

Exercise of warrants (shares) | shares

153,534

Warrants exercised 2 [Member]

Statement [Line Items]

Exercise of warrants (shares) | shares

12,791,500

Weighted average exercise price of warrants exercised in share-based payment arrangement

CAD 0.65

Proceeds from exercise of warrants

8,314,475

Warrants exercised 2 [Member] | Reserves [Member]

Statement [Line Items]

Exercise of warrants

CAD 639,575

RELATED PARTY TRANSACTIONS (Nar

RELATED PARTY TRANSACTIONS (Narrative) (Details) - CAD	1 Months Ended	12 Months Ended
	Feb. 26, 2016	Dec. 31, 2017	Dec. 31, 2016
Statement [Line Items]
Key management personnel compensation, short-term employee benefits		CAD 4,101,441	CAD 3,189,845
Key management personnel compensation, share-based payment		8,830,606	7,686,442
Amounts payable, related party transactions		CAD 542,361	CAD 15,000
Issue of shares for exploration and evaluation assets (shares)		111,110	49,861
NxGold [Member]
Statement [Line Items]
Issue of shares for exploration and evaluation assets (shares)	49,861
Increase in ownership interest due to issuances of shares	25.00%
Expensed and included in salaries, benefits and directors fees on the statement of loss and comprehensive loss [Member]
Statement [Line Items]
Key management personnel compensation, short-term employee benefits		CAD 3,164,827	CAD 2,474,975
Key management personnel compensation, share-based payment		7,696,538	6,921,942
Capitalized to exploration and evaluation assets [Member]
Statement [Line Items]
Key management personnel compensation, short-term employee benefits		936,614	714,870
Key management personnel compensation, share-based payment		CAD 1,134,068	CAD 764,500

FINANCIAL INSTRUMENTS (Narrativ

FINANCIAL INSTRUMENTS (Narrative) (Details)	12 Months Ended
	Dec. 31, 2017CAD	Dec. 31, 2017USD ($)	Dec. 31, 2017AUD	Dec. 31, 2016CAD	Dec. 31, 2015CAD
Statement [Line Items]
Cash and cash equivalents	CAD 164,943,850			CAD 31,090,313	CAD 34,303,982
Accounts payable and accrued liabilities	CAD 2,905,179			CAD 2,248,912
Convertible debentures, aggregate principal amount | $		$ 120,000,000
Borrowings, interest rate	7.50%	7.50%	7.50%
Amounts held in foreign currencies [Member]
Statement [Line Items]
Financial assets, net | AUD			AUD 9,828
Financial liabilities, net | $		$ 113,779,379
Percentage of reasonably possible change in currency rates	10.00%
Value at risk	CAD 12,153,954

NON-CONTROLLING INTERESTS (Narr

NON-CONTROLLING INTERESTS (Narrative) (Details)	1 Months Ended				12 Months Ended
	Jul. 21, 2017CAD	Jul. 21, 2017USD ($)	Aug. 31, 2016CADshares	Jun. 30, 2016shares	Dec. 31, 2017CADshares	Dec. 31, 2016CADshares	Jun. 17, 2017shares
Statement [Line Items]
Issue of shares for exploration and evaluation assets (shares)					111,110	49,861
Proceeds from issuing shares	CAD 62,745,000	$ 50,000,000			CAD 60,225,368	CAD 0
The subsidiaries with the exception of IsoEnergy [Member]
Statement [Line Items]
Proportion of ownership interest in subsidiary					100.00%
IsoEnergy Ltd. [Member]
Statement [Line Items]
Proportion of ownership interest in subsidiary					63.90%
Number of ownership interests held							29,000,000
Issue of shares for exploration and evaluation assets (shares)					4,000,000
Receivables due from related parties | CAD			CAD 450,000
Increase in number of shares outstanding, conversion of debt			450,000
Increase in number of shares outstanding, issued to an unrelated third party			302,881			6,364,450
Increase in number of flow through shares outstanding					999,999	3,934,636
Proceeds from issuing shares | CAD					CAD 1,100,000	CAD 10,692,550
Increase in number of flow through shares outstanding, finder's fee						8,580
IsoEnergy Ltd. [Member] | Thorburn North property [Member]
Statement [Line Items]
Issue of shares for exploration and evaluation assets (shares)				1,000,000
Increase in ownership interest due to issuances of shares				100.00%
IsoEnergy Ltd. [Member] | Radio property [Member]
Statement [Line Items]
Issue of shares for exploration and evaluation assets (shares)					3,000,000
IsoEnergy Ltd. [Member] | Geiger property [Member]
Statement [Line Items]
Issue of shares for exploration and evaluation assets (shares)					1,000,000	1,000,000

SUPPLEMENTAL DISCLOSURE WITH 43

SUPPLEMENTAL DISCLOSURE WITH RESPECT TO CASH FLOWS (Narrative) (Details) - CAD

Dec. 12, 2017

Dec. 11, 2017

Jun. 12, 2017

Dec. 12, 2016

Feb. 11, 2016

Sep. 18, 2017

Dec. 31, 2016

Sep. 30, 2016

Jun. 30, 2016

Mar. 31, 2016

Dec. 31, 2017

Dec. 31, 2016

Statement [Line Items]

Issue of shares on convertible debenture interest payment (shares)

555,670

555,670

327,863

521,115

883,533

521,115

Issue of shares on convertible debenture interest payment

CAD 1,955,959

CAD 1,955,958

CAD 963,917

CAD 1,125,608

CAD 2,919,876

CAD 1,125,608

Share-based payments

9,183,667

8,100,213

Exercise of options

CAD (1,128,032)

CAD (1,217,060)

Issue of shares for exploration and evaluation assets (shares)

111,110

49,861

Issue of shares for exploration and evaluation assets

CAD 333,330

CAD 48,864

Exercise of warrants

CAD (2,857,143)

CAD (9,366,182)

Dufferin Lake property [Member]

Statement [Line Items]

Issue of shares for exploration and evaluation assets (shares)

111,110

111,110

Increase in ownership interest due to issuances of shares

40.00%

40.00%

Issue of shares for exploration and evaluation assets

CAD 333,330

CAD 333,330

IsoEnergy Ltd. [Member]

Statement [Line Items]

Issue of shares for exploration and evaluation assets (shares)

4,000,000

Issue of shares for exploration and evaluation assets

CAD 3,040,000

IsoEnergy Ltd. [Member] | Geiger property [Member]

Statement [Line Items]

Issue of shares for exploration and evaluation assets (shares)

1,000,000

1,000,000

Issue of shares for exploration and evaluation assets

CAD 1,000,000

Reserves [Member]

Statement [Line Items]

Exercise of options

CAD 440,721

CAD 223,607

CAD 21,306

CAD 40,940

CAD 853,100

726,574

Exercise of warrants

CAD 221,089

934,361

Included in accounts payable and accrued liabilities [Member]

Statement [Line Items]

Exploration and evaluation asset expenditures

612,900

535,444

Equipment expenditures

305,135

157,040

Interest expense related to convertible debentures

689,976

Included in exploration and evaluation assets [Member]

Statement [Line Items]

Share-based payments

CAD 3,309,791

CAD 3,036,207

SUBSEQUENT EVENTS (Narrative) (

SUBSEQUENT EVENTS (Narrative) (Details)	Jan. 08, 2018CAD	Dec. 31, 2016CADshares	Sep. 30, 2016CADshares	Jun. 30, 2016CADshares	Mar. 31, 2016CADshares	Dec. 31, 2017CADshares	Dec. 31, 2016CADshares
Statement [Line Items]
Exercise of options (shares) | shares		1,766,666	875,000	110,000	190,000	1,424,445	2,941,666
Weighted average exercise price of share options exercised in share-based payment arrangement						CAD 0.79	CAD 0.41
Proceeds from exercise of options		CAD 733,560	CAD 355,500	CAD 45,500	CAD 82,500	CAD 1,128,032
Number of share options granted in share-based payment arrangement						6,200,000	10,200,000
Weighted average exercise price of share options granted in share-based payment arrangement						CAD 3.27	CAD 2.45
Subsequent Events [Member]
Statement [Line Items]
Exercise of options (shares) | shares						3,983,334
Proceeds from exercise of options						CAD 1,975,334
Number of share options granted in share-based payment arrangement	440,000
Weighted average exercise price of share options granted in share-based payment arrangement	CAD 0.57
Subsequent Events [Member] | Bottom of range [Member]
Statement [Line Items]
Weighted average exercise price of share options exercised in share-based payment arrangement						0.40
Subsequent Events [Member] | Top of range [Member]
Statement [Line Items]
Weighted average exercise price of share options exercised in share-based payment arrangement						CAD 1.51

Disclosure of subsidiaries (Det

Disclosure of subsidiaries (Details)	12 Months Ended
	Dec. 31, 2017
NXE Energy Royalty Ltd. [Member]
Statement [Line Items]
Proportion of ownership interest in subsidiary	100.00%
NXE Energy SW1 Ltd. [Member]
Statement [Line Items]
Proportion of ownership interest in subsidiary	100.00%
NXE Energy SW3 Ltd. [Member]
Statement [Line Items]
Proportion of ownership interest in subsidiary	100.00%
IsoEnergy Ltd. [Member]
Statement [Line Items]
Proportion of ownership interest in subsidiary	63.90%

Disclosure of detailed informat

Disclosure of detailed information about estimated useful life or depreciation rate (Details)	12 Months Ended
	Dec. 31, 2017
Field equipment [Member]
Statement [Line Items]
Useful lives or depreciation rates, property, plant and equipment	20% declining balance basis
Leasehold improvements [Member]
Statement [Line Items]
Useful lives or depreciation rates, property, plant and equipment	5-year lease term
Road [Member]
Statement [Line Items]
Useful lives or depreciation rates, property, plant and equipment	5-year straight-line basis
Computing equipment [Member]
Statement [Line Items]
Useful lives or amortisation rates, intangible assets other than goodwill	55% declining balance basis
Software [Member]
Statement [Line Items]
Useful lives or amortisation rates, intangible assets other than goodwill	55% declining balance basis

Disclosure of detailed inform47

Disclosure of detailed information about exploration and evaluation assets (Details) - CAD	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Statement [Line Items]
Exploration and evaluation assets, beginning balance	CAD 109,446,920
Impairment	(87,749)	CAD (964,858)
Exploration and evaluation assets, ending balance	152,412,555	109,446,920
Acquisition costs [Member]
Statement [Line Items]
Exploration and evaluation assets, beginning balance	22,793,390	21,629,432
Additions	3,636,542	1,163,958
Properties transferred to IsoEnergy		0
Exploration and evaluation assets, ending balance	26,429,932	22,793,390
Deferred exploration costs [Member]
Statement [Line Items]
Exploration and evaluation assets, beginning balance	86,653,530	43,507,081
Expense arising from exploration for and evaluation of mineral resources	39,416,842	44,111,307
Properties transferred to IsoEnergy		0
Impairment	(87,749)	(964,858)
Exploration and evaluation assets, ending balance	125,982,623	86,653,530
Deferred exploration costs [Member] | Drilling [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	21,764,192	26,203,084
Deferred exploration costs [Member] | General exploration [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	2,300,042	2,411,751
Deferred exploration costs [Member] | Geological and geophysical [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	6,409,853	8,207,716
Deferred exploration costs [Member] | Labour and wages [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	4,901,854	3,906,313
Deferred exploration costs [Member] | Share-based payments [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	3,309,791	3,036,207
Deferred exploration costs [Member] | Travel [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	731,110	346,236
Rook 1 Property [Member]
Statement [Line Items]
Exploration and evaluation assets, beginning balance	77,238,110
Exploration and evaluation assets, ending balance	113,173,036	77,238,110
Rook 1 Property [Member] | Acquisition costs [Member]
Statement [Line Items]
Exploration and evaluation assets, beginning balance	230,807	220,713
Additions	4,270	10,094
Properties transferred to IsoEnergy		0
Exploration and evaluation assets, ending balance	235,077	230,807
Rook 1 Property [Member] | Deferred exploration costs [Member]
Statement [Line Items]
Exploration and evaluation assets, beginning balance	77,007,303	37,803,918
Expense arising from exploration for and evaluation of mineral resources	35,930,656	39,203,385
Properties transferred to IsoEnergy		0
Impairment	0	0
Exploration and evaluation assets, ending balance	112,937,959	77,007,303
Rook 1 Property [Member] | Deferred exploration costs [Member] | Drilling [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	20,592,799	24,989,860
Rook 1 Property [Member] | Deferred exploration costs [Member] | General exploration [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	2,163,554	2,283,418
Rook 1 Property [Member] | Deferred exploration costs [Member] | Geological and geophysical [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	5,206,266	5,333,676
Rook 1 Property [Member] | Deferred exploration costs [Member] | Labour and wages [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	4,391,456	3,542,893
Rook 1 Property [Member] | Deferred exploration costs [Member] | Share-based payments [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	2,952,316	2,779,787
Rook 1 Property [Member] | Deferred exploration costs [Member] | Travel [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	624,265	273,751
Other Athabasca Basin Properties [Member]
Statement [Line Items]
Exploration and evaluation assets, beginning balance	5,443,186
Impairment	(87,749)	(964,858)
Exploration and evaluation assets, ending balance	6,399,904	5,443,186
Other Athabasca Basin Properties [Member] | Acquisition costs [Member]
Statement [Line Items]
Exploration and evaluation assets, beginning balance	1,124,277	1,274,966
Additions	333,330	53,864
Properties transferred to IsoEnergy		(204,553)
Exploration and evaluation assets, ending balance	1,457,607	1,124,277
Other Athabasca Basin Properties [Member] | Deferred exploration costs [Member]
Statement [Line Items]
Exploration and evaluation assets, beginning balance	4,318,909	3,409,339
Expense arising from exploration for and evaluation of mineral resources	711,137	2,016,108
Properties transferred to IsoEnergy		(141,680)
Impairment	(87,749)	(964,858)
Exploration and evaluation assets, ending balance	4,942,297	4,318,909
Other Athabasca Basin Properties [Member] | Deferred exploration costs [Member] | Drilling [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	3,297	16,061
Other Athabasca Basin Properties [Member] | Deferred exploration costs [Member] | General exploration [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	25,885	8,873
Other Athabasca Basin Properties [Member] | Deferred exploration costs [Member] | Geological and geophysical [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	681,955	1,991,174
Other Athabasca Basin Properties [Member] | Deferred exploration costs [Member] | Labour and wages [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	0	0
Other Athabasca Basin Properties [Member] | Deferred exploration costs [Member] | Share-based payments [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	0	0
Other Athabasca Basin Properties [Member] | Deferred exploration costs [Member] | Travel [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	0	0
IsoEnergy Properties [Member]
Statement [Line Items]
Exploration and evaluation assets, beginning balance	26,765,624
Exploration and evaluation assets, ending balance	32,839,615	26,765,624
IsoEnergy Properties [Member] | Acquisition costs [Member]
Statement [Line Items]
Exploration and evaluation assets, beginning balance	21,438,306	0
Additions	3,298,942	1,100,000
Properties transferred to IsoEnergy		20,338,306
Exploration and evaluation assets, ending balance	24,737,248	21,438,306
IsoEnergy Properties [Member] | Deferred exploration costs [Member]
Statement [Line Items]
Exploration and evaluation assets, beginning balance	5,327,318	0
Expense arising from exploration for and evaluation of mineral resources	2,775,049	2,891,814
Properties transferred to IsoEnergy		2,435,504
Impairment	0	0
Exploration and evaluation assets, ending balance	8,102,367	5,327,318
IsoEnergy Properties [Member] | Deferred exploration costs [Member] | Drilling [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	1,168,096	1,197,163
IsoEnergy Properties [Member] | Deferred exploration costs [Member] | General exploration [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	110,603	119,460
IsoEnergy Properties [Member] | Deferred exploration costs [Member] | Geological and geophysical [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	521,632	882,866
IsoEnergy Properties [Member] | Deferred exploration costs [Member] | Labour and wages [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	510,398	363,420
IsoEnergy Properties [Member] | Deferred exploration costs [Member] | Share-based payments [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	357,475	256,420
IsoEnergy Properties [Member] | Deferred exploration costs [Member] | Travel [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources	106,845	72,485
Radio property [Member]
Statement [Line Items]
Exploration and evaluation assets, beginning balance	0
Exploration and evaluation assets, ending balance		0
Radio property [Member] | Acquisition costs [Member]
Statement [Line Items]
Exploration and evaluation assets, beginning balance	0	20,133,753
Additions		0
Properties transferred to IsoEnergy		(20,133,753)
Exploration and evaluation assets, ending balance		0
Radio property [Member] | Deferred exploration costs [Member]
Statement [Line Items]
Exploration and evaluation assets, beginning balance	CAD 0	2,293,824
Expense arising from exploration for and evaluation of mineral resources		0
Properties transferred to IsoEnergy		(2,293,824)
Impairment		0
Exploration and evaluation assets, ending balance		0
Radio property [Member] | Deferred exploration costs [Member] | Drilling [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources		0
Radio property [Member] | Deferred exploration costs [Member] | General exploration [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources		0
Radio property [Member] | Deferred exploration costs [Member] | Geological and geophysical [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources		0
Radio property [Member] | Deferred exploration costs [Member] | Labour and wages [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources		0
Radio property [Member] | Deferred exploration costs [Member] | Share-based payments [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources		0
Radio property [Member] | Deferred exploration costs [Member] | Travel [Member]
Statement [Line Items]
Expense arising from exploration for and evaluation of mineral resources		CAD 0

Disclosure of detailed inform48

Disclosure of detailed information about flow-through share premium liability (Details) - CAD	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Statement [Line Items]
Flow-through share premium liability, beginning balance	CAD 179,212	CAD 0
Liability incurred on flow-through shares issued	130,000	393,464
Settlement of flow-through share liability on expenditure made	(199,961)	(214,252)
Flow-through share premium liability, ending balance	CAD 109,251	CAD 179,212

Disclosure of leases (Details)

Disclosure of leases (Details) - CAD	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Office lease [Member]
Statement [Line Items]
Office lease commitments	CAD 199,466	CAD 325,294	CAD 360,975

Disclosure of detailed inform50

Disclosure of detailed information about equipment (Details) - CAD	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Statement [Line Items]
Property, plant and equipment at beginning of period	CAD 3,601,178
Property, plant and equipment at end of period	4,983,074	CAD 3,601,178
Cost [Member]
Statement [Line Items]
Property, plant and equipment at beginning of period	4,644,320	1,581,463
Additions	2,206,276	3,062,857
Disposals	(29,300)
Property, plant and equipment at end of period	6,821,296	4,644,320
Accumulated Depreciation [Member]
Statement [Line Items]
Property, plant and equipment at beginning of period	1,043,142	393,932
Depreciation	799,475	649,210
Disposals	(4,395)
Property, plant and equipment at end of period	1,838,222	1,043,142
Field equipment [Member]
Statement [Line Items]
Property, plant and equipment at beginning of period	2,113,183
Property, plant and equipment at end of period	3,096,420	2,113,183
Field equipment [Member] | Cost [Member]
Statement [Line Items]
Property, plant and equipment at beginning of period	2,756,640	1,237,013
Additions	1,490,880	1,519,627
Disposals	(29,300)
Property, plant and equipment at end of period	4,218,220	2,756,640
Field equipment [Member] | Accumulated Depreciation [Member]
Statement [Line Items]
Property, plant and equipment at beginning of period	643,457	305,114
Depreciation	482,738	338,343
Disposals	(4,395)
Property, plant and equipment at end of period	1,121,800	643,457
Leasehold improvements [Member]
Statement [Line Items]
Property, plant and equipment at beginning of period	167,328
Property, plant and equipment at end of period	124,642	167,328
Leasehold improvements [Member] | Cost [Member]
Statement [Line Items]
Property, plant and equipment at beginning of period	215,172	183,034
Additions	0	32,138
Disposals	0
Property, plant and equipment at end of period	215,172	215,172
Leasehold improvements [Member] | Accumulated Depreciation [Member]
Statement [Line Items]
Property, plant and equipment at beginning of period	47,844	6,101
Depreciation	42,686	41,743
Disposals	0
Property, plant and equipment at end of period	90,530	47,844
Road [Member]
Statement [Line Items]
Property, plant and equipment at beginning of period	1,119,805
Property, plant and equipment at end of period	1,511,560	1,119,805
Road [Member] | Cost [Member]
Statement [Line Items]
Property, plant and equipment at beginning of period	1,282,890	0
Additions	490,695	1,282,890
Disposals	0
Property, plant and equipment at end of period	1,773,585	1,282,890
Road [Member] | Accumulated Depreciation [Member]
Statement [Line Items]
Property, plant and equipment at beginning of period	163,085	0
Depreciation	98,940	163,085
Disposals	0
Property, plant and equipment at end of period	262,025	163,085
Computing equipment [Member]
Statement [Line Items]
Property, plant and equipment at beginning of period	42,469
Property, plant and equipment at end of period	107,663	42,469
Computing equipment [Member] | Cost [Member]
Statement [Line Items]
Property, plant and equipment at beginning of period	109,648	65,490
Additions	125,938	44,158
Disposals	0
Property, plant and equipment at end of period	235,586	109,648
Computing equipment [Member] | Accumulated Depreciation [Member]
Statement [Line Items]
Property, plant and equipment at beginning of period	67,179	42,259
Depreciation	60,744	24,920
Disposals	0
Property, plant and equipment at end of period	127,923	67,179
Software [Member]
Statement [Line Items]
Property, plant and equipment at beginning of period	158,393
Property, plant and equipment at end of period	142,789	158,393
Software [Member] | Cost [Member]
Statement [Line Items]
Property, plant and equipment at beginning of period	279,970	95,926
Additions	98,763	184,044
Disposals	0
Property, plant and equipment at end of period	378,733	279,970
Software [Member] | Accumulated Depreciation [Member]
Statement [Line Items]
Property, plant and equipment at beginning of period	121,577	40,458
Depreciation	114,367	81,119
Disposals	0
Property, plant and equipment at end of period	CAD 235,944	CAD 121,577

Disclosure of detailed inform51

Disclosure of detailed information about convertible debentures (Details) - CAD	Dec. 31, 2017	Dec. 31, 2016
Statement [Line Items]
Convertible debentures	CAD 171,369,966	CAD 70,811,801
2016 Debentures [Member]
Statement [Line Items]
Convertible debentures	90,742,373	70,811,801
2017 Debentures [Member]
Statement [Line Items]
Convertible debentures	CAD 80,627,593	CAD 0

Disclosure of detailed inform52

Disclosure of detailed information about convertible debentures, fair value and interest components (Details)	Dec. 31, 2017CAD	Dec. 31, 2017USD ($)	Jul. 21, 2017CAD	Jul. 21, 2017USD ($)	Dec. 31, 2016CAD	Dec. 31, 2016USD ($)	Jun. 10, 2016CAD	Jun. 10, 2016USD ($)
Statement [Line Items]
Convertible debentures	CAD 171,369,966				CAD 70,811,801
2016 Debentures [Member]
Statement [Line Items]
Convertible debentures at fair value	90,742,373	$ 72,333,498			70,811,801	$ 52,738,364	CAD 74,123,520	$ 58,200,000
Fair value adjustment	19,930,572				(3,311,719)
Interest payable	350,900				369,243
Convertible debentures and interest payable	91,093,273				71,181,044
Less: interest payable included in accounts payable and accrued liabilities	(350,900)				(369,243)
Convertible debentures	90,742,373				70,811,801
2017 Debentures [Member]
Statement [Line Items]
Convertible debentures at fair value	80,627,593	$ 64,270,700	CAD 73,035,180	$ 58,200,000
Fair value adjustment	7,592,413
Interest payable	350,900
Convertible debentures and interest payable	80,978,493
Less: interest payable included in accounts payable and accrued liabilities	(350,900)
Convertible debentures	CAD 80,627,593				CAD 0

Disclosure of detailed inform53

Disclosure of detailed information about convertible debentures, valuation assumptions (Details)	1 Months Ended	12 Months Ended
	Jul. 21, 2017CAD	Dec. 31, 2017CAD	Dec. 31, 2016CAD	Dec. 31, 2017USD ($)	Jul. 21, 2017USD ($)	Dec. 31, 2016USD ($)
2016 Debentures [Member]
Statement [Line Items]
Historical stock price volatility		39.00%	40.00%
Expected life in years		4.56 years	4.44 years
Risk free interest rate		2.23%	1.91%
Expected dividend yield		0.00%	0.00%
Credit spread		25.35%	26.44%
Underlying share price of the Company | CAD		CAD 3.21	CAD 2.33
Conversion exercise price | $				$ 2.3261		$ 2.3261
Exchange rate (C$:US$)		0.7971	0.7448	0.7971		0.7448
2017 Debentures [Member]
Statement [Line Items]
Historical stock price volatility	38.00%	39.00%
Expected life in years	5.00 years	4.56 years
Risk free interest rate	1.88%	2.23%
Expected dividend yield	0.00%	0.00%
Credit spread	25.35%	25.35%
Underlying share price of the Company | CAD	CAD 3.04	CAD 3.21
Conversion exercise price | $				$ 2.6919	$ 2.6919
Exchange rate (C$:US$)	0.7969	0.7971		0.7971	0.7969

Disclosure of detailed inform54

Disclosure of detailed information about warrants, activity (Details)	Feb. 12, 2016CAD	Feb. 11, 2016CAD	May 31, 2017CAD	Dec. 31, 2017CAD	Dec. 31, 2016CAD
Statement [Line Items]
Number of warrants outstanding, beginning balance				5,714,286	19,918,592
Weighted average exercise price of warrants outstanding in share-based payment arrangement, beginning balance				CAD 0.50	CAD 0.59
Number of warrants exercised in share-based payment arrangement				(5,714,286)	(14,787,443)
Weighted average exercise price of warrants exercised in share-based payment arrangement	CAD 0.65	CAD 0.65	CAD 0.50	CAD 0.50	CAD 0.63
Number of warrants granted in share-based payment arrangement					614,137
Weighted average exercise price of warrants granted in share-based payment arrangement					CAD 0.65
Number of warrants expired in share-based payment arrangement					(31,000)
Weighted average exercise price of warrants expired in share-based payment arrangement					CAD 0.65
Number of warrants outstanding, ending balance				0	5,714,286
Weighted average exercise price of warrants outstanding in share-based payment arrangement, ending balance				CAD 0	CAD 0.50

Disclosure of number and weight

Disclosure of number and weighted average exercise prices of share options (Details)	12 Months Ended
	Dec. 31, 2017CAD	Dec. 31, 2016CAD
Statement [Line Items]
Number of share options outstanding in share-based payment arrangement at beginning of period	33,466,112	27,124,446
Weighted average exercise price of share options outstanding in share-based payment arrangement at beginning of period	CAD 1.06	CAD 0.48
Number of share options granted in share-based payment arrangement	6,200,000	10,200,000
Weighted average exercise price of share options granted in share-based payment arrangement	CAD 3.27	CAD 2.45
Number of share options exercised in share-based payment arrangement	(1,424,445)	(2,941,666)
Weighted average exercise price of share options exercised in share-based payment arrangement	CAD 0.79	CAD 0.41
Number of share options expired in share-based payment arrangement		(116,667)
Weighted average exercise price of share options expired in share-based payment arrangement		CAD 2.65
Number of share options forfeited in share-based payment arrangement	(383,333)	(800,001)
Weighted average exercise price of share options forfeited in share-based payment arrangement	CAD 2.53	CAD 1.36
Number of share options outstanding in share-based payment arrangement at end of period	37,858,334	33,466,112
Weighted average exercise price of share options outstanding in share-based payment arrangement at end of period	CAD 1.42	CAD 1.06
Number of share options exercisable in share-based payment arrangement	30,783,334
Weighted average exercise price of share options exercisable in share-based payment arrangement	CAD 1.07

Disclosure of number and weig56

Disclosure of number and weighted average remaining contractual life of outstanding share options (Details)	Dec. 31, 2017CAD	Dec. 31, 2016CAD	Dec. 31, 2015CAD
Statement [Line Items]
Number of Options	37,858,334	33,466,112	27,124,446
Number Exercisable	30,783,334
Exercise Price	CAD 1.42	CAD 1.06	CAD 0.48
Expire January 31, 2018 [Member]
Statement [Line Items]
Number of Options	3,600,000
Number Exercisable	3,600,000
Exercise Price	CAD 0.400
Remaining Contractual Life (Years)	0.08
Expire March 12, 2018 [Member]
Statement [Line Items]
Number of Options	333,334
Number Exercisable	333,334
Exercise Price	CAD 1.510
Remaining Contractual Life (Years)	0.19
Expire July 30, 2018 [Member]
Statement [Line Items]
Number of Options	1,450,000
Number Exercisable	1,450,000
Exercise Price	CAD 0.400
Remaining Contractual Life (Years)	0.58
Expire December 19, 2018 [Member]
Statement [Line Items]
Number of Options	250,000
Number Exercisable	250,000
Exercise Price	CAD 0.300
Remaining Contractual Life (Years)	0.97
Expire May 23, 2019 [Member]
Statement [Line Items]
Number of Options	2,625,000
Number Exercisable	2,625,000
Exercise Price	CAD 0.400
Remaining Contractual Life (Years)	1.39
Expire June 2, 2019 [Member]
Statement [Line Items]
Number of Options	750,000
Number Exercisable	750,000
Exercise Price	CAD 0.400
Remaining Contractual Life (Years)	1.42
Expire December 24, 2019 [Member]
Statement [Line Items]
Number of Options	4,550,000
Number Exercisable	4,550,000
Exercise Price	CAD 0.460
Remaining Contractual Life (Years)	1.98
Expire May 27, 2020 [Member]
Statement [Line Items]
Number of Options	4,200,000
Number Exercisable	4,200,000
Exercise Price	CAD 0.500
Remaining Contractual Life (Years)	2.41
Expire September 22, 2020 [Member]
Statement [Line Items]
Number of Options	500,000
Number Exercisable	500,000
Exercise Price	CAD 0.620
Remaining Contractual Life (Years)	2.73
Expire December 16, 2020 [Member]
Statement [Line Items]
Number of Options	4,575,000
Number Exercisable	4,575,000
Exercise Price	CAD 0.640
Remaining Contractual Life (Years)	2.96
Expire June 8, 2021 [Member]
Statement [Line Items]
Number of Options	250,000
Number Exercisable	166,667
Exercise Price	CAD 2.690
Remaining Contractual Life (Years)	3.44
Expire June 23, 2021 [Member]
Statement [Line Items]
Number of Options	5,275,000
Number Exercisable	3,516,666
Exercise Price	CAD 2.650
Remaining Contractual Life (Years)	3.48
Expire December 15, 2021 [Member]
Statement [Line Items]
Number of Options	3,300,000
Number Exercisable	2,200,000
Exercise Price	CAD 2.240
Remaining Contractual Life (Years)	3.96
Expire January 19, 2022 [Member]
Statement [Line Items]
Number of Options	150,000
Number Exercisable	50,000
Exercise Price	CAD 3.300
Remaining Contractual Life (Years)	4.05
Expire April 22, 2022 [Member]
Statement [Line Items]
Number of Options	250,000
Number Exercisable	83,334
Exercise Price	CAD 3.110
Remaining Contractual Life (Years)	4.31
Expire November 13, 2022 [Member]
Statement [Line Items]
Number of Options	1,475,000
Number Exercisable	491,666
Exercise Price	CAD 2.930
Remaining Contractual Life (Years)	4.87
Expire December 14, 2022 [Member]
Statement [Line Items]
Number of Options	4,325,000
Number Exercisable	1,441,667
Exercise Price	CAD 3.390
Remaining Contractual Life (Years)	4.96

Disclosure of detailed inform57

Disclosure of detailed information about options, valuation assumptions (Details) - CAD	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Statement [Line Items]
Expected stock price volatility	81.72%	87.15%
Expected life of options	5	5
Risk free interest rate	1.53%	0.68%
Expected forfeitures	0.00%	0.00%
Expected dividend yield	0.00%	0.00%
Weighted average fair value per option granted in the year	CAD 2.13	CAD 1.65

Disclosure of reserves within e

Disclosure of reserves within equity (Details) - CAD	Feb. 11, 2016	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Statement [Line Items]
Beginning Balance					CAD 100,155,637	CAD 119,006,266	CAD 100,155,637
Exercise of options						1,128,032	1,217,060
Exercise of warrants						2,857,143	9,366,182
Share-based payments						12,493,458	11,136,420
Ending Balance		CAD 119,006,266				148,340,705	119,006,266
Reserves [Member]
Statement [Line Items]
Beginning Balance					7,530,180	17,005,665	7,530,180
Exercise of options		(440,721)	CAD (223,607)	CAD (21,306)	CAD (40,940)	(853,100)	(726,574)
Exercise of warrants	CAD (221,089)						(934,361)
Expired warrants adjustment						(595,964)
Share-based payments						12,493,458	11,136,420
Ending Balance		CAD 17,005,665				CAD 28,050,059	CAD 17,005,665

Disclosure of information about

Disclosure of information about key management personnel (Details) - CAD	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Statement [Line Items]
Key management personnel compensation, short-term employee benefits	CAD 4,101,441	CAD 3,189,845
Key management personnel compensation, share-based payment	8,830,606	7,686,442
Remuneration attributed to key management personnel	CAD 12,932,047	CAD 10,876,287

Disclosure of detailed inform60

Disclosure of detailed information about effective income tax expense recovery (Details) - CAD	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Statement [Line Items]
Net loss for the year	CAD (56,863,922)	CAD (17,455,889)
Statutory rate	26.75%	27.00%
Rounded amount [Member]
Statement [Line Items]
Expected income tax recovery	CAD (15,211,000)	CAD (4,713,000)
Permanent differences	1,431,000	1,805,000
Impact of flow-through shares	580,000	480,000
Share issuances costs	(1,276,000)	0
Adjustment to prior years provision versus statutory tax returns	(597,000)	126,000
Change in unrecognized deductible temporary differences and other	15,040,000	2,378,000
Total	CAD (33,000)	CAD 76,000

Disclosure of deferred taxes (D

Disclosure of deferred taxes (Details) - CAD	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Statement [Line Items]
Deferred income tax expense	CAD (33,312)	CAD 75,776
Rounded amount [Member]
Statement [Line Items]
Deferred income tax expense	(33,000)	76,000
Total	CAD (33,000)	CAD 76,000

Disclosure of deferred tax liab

Disclosure of deferred tax liabilities (Details) - CAD	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement [Line Items]
Net deferred tax liabilities	CAD 280,740	CAD 136,588
Rounded amount [Member]
Statement [Line Items]
Net deferred tax liabilities	280,000	137,000	CAD 0
Exploration and evaluation assets [Member] | Rounded amount [Member]
Statement [Line Items]
Net deferred tax liabilities	4,333,000	3,532,000
Convertible debentures [Member] | Rounded amount [Member]
Statement [Line Items]
Net deferred tax liabilities	0	1,454,000
Non-capital losses [Member] | Rounded amount [Member]
Statement [Line Items]
Net deferred tax liabilities	(3,916,000)	(4,004,000)
Share issuance costs [Member] | Rounded amount [Member]
Statement [Line Items]
Net deferred tax liabilities	(119,000)	(839,000)
Equipment [Member] | Rounded amount [Member]
Statement [Line Items]
Net deferred tax liabilities	CAD (18,000)	CAD (6,000)

Disclosure of detailed inform63

Disclosure of detailed information about deferred tax liabilities (Details) - CAD	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Statement [Line Items]
Opening balance	CAD 136,588
Net deferred tax liability	280,740	CAD 136,588
Rounded amount [Member]
Statement [Line Items]
Opening balance	137,000	0
Recognized in income tax expense	167,000	290,000
Recognized in equity	(24,000)	(153,000)
Net deferred tax liability	CAD 280,000	CAD 137,000

Disclosure of temporary differe

Disclosure of temporary difference, unused tax losses and unused tax credits (Details) - Rounded amount [Member] - CAD	Dec. 31, 2017	Dec. 31, 2016
Non-capital losses available for future periods [Member]
Statement [Line Items]
Temporary Differences	CAD 24,735,000	CAD 0
Net capital losses [Member]
Statement [Line Items]
Temporary Differences	355,000	0
Share issuance costs [Member]
Statement [Line Items]
Temporary Differences	12,148,000	6,101,000
Convertible debt [Member]
Statement [Line Items]
Temporary Differences	24,211,000	0
Equipment [Member]
Statement [Line Items]
Temporary Differences	CAD 513,000	CAD 1,140,000

Disclosure of summarized financ

Disclosure of summarized financial information for subsidiaries with material non-controlling interests (Details) - CAD	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement [Line Items]
Cash and cash equivalents	CAD 164,943,850	CAD 31,090,313	CAD 34,303,982
Non-current assets	157,428,556	113,070,950
TOTAL ASSETS	323,079,350	192,496,385
Current liabilities	3,014,430	2,428,124
Non-current liabilities	171,724,215	71,061,995
TOTAL LIABILITIES	174,738,645	73,490,119
Loss from operations	56,863,922	17,455,889
Loss and comprehensive loss	56,830,610	17,531,665
Net cash flow from operating activities	(11,144,497)	(8,024,952)
Net cash flow from investing activities	9,634,529	(91,293,716)
Net cash flow from financing activities	135,105,106	95,139,915
Change in cash and cash equivalents	133,595,138	(4,178,753)
Subsidiaries with material non-controlling interests [Member]
Statement [Line Items]
Cash and cash equivalents	3,325,000	6,492,000
Other current assets	67,000	214,000
Non-current assets	39,124,000	33,086,000
TOTAL ASSETS	42,516,000	39,792,000
Current liabilities	247,000	468,000
Non-current liabilities	281,000	137,000
TOTAL LIABILITIES	528,000	605,000
Loss from operations	2,516,000	2,255,000
Loss and comprehensive loss	2,462,000	2,470,000
Net cash flow from operating activities	(1,536,000)	(1,266,000)
Net cash flow from investing activities	(2,647,000)	(2,825,000)
Net cash flow from financing activities	1,017,000	10,583,000
Change in cash and cash equivalents	CAD (3,166,000)	CAD 6,492,000