Southern Copper (SCCO) 10-K26 Feb 212020 FY Annual reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2020	Feb. 24, 2021	Jun. 30, 2020
Document and Entity Information
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	1-14066
Entity Registrant Name	SOUTHERN COPPER CORP/
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	13-3849074
Entity Address, Address Line One	1440 East Missouri Avenue Suite 160
Entity Address, City or Town	Phoenix
Entity Address, State or Province	AZ
Entity Address, Postal Zip Code	85014
City Area Code	602
Local Phone Number	264-1375
Title of 12(b) Security	Common stock
Trading Symbol	SCCO
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
ICFR Auditor Attestation Flag	true
Entity Common Stock, Shares Outstanding		773,073,269
Entity Public Float			$ 3,411.6
Entity Central Index Key	0001001838
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false

CONSOLIDATED STATEMENTS OF EARN

CONSOLIDATED STATEMENTS OF EARNINGS - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CONSOLIDATED STATEMENTS OF EARNINGS
Net sales (including sales to related parties, see note 17)	$ 7,984.9	$ 7,285.6	$ 7,096.7
Operating cost and expenses:
Cost of sales (exclusive of depreciation, amortization and depletion shown separately below)	3,929.8	3,606.4	3,409
Selling, general and administrative	126.2	131.8	102.6
Depreciation, amortization and depletion	775.6	764.4	674.3
Exploration	32.6	30	29.6
Total operating costs and expenses	4,864.2	4,532.6	4,215.5
Operating income	3,120.7	2,753	2,881.2
Interest expense	(393.4)	(372.9)	(360.9)
Capitalized interest	26.8	32.2	83.8
Other income (expense)	(27.5)	(7)	(30.7)
Interest income	19.2	21.2	16
Income before income taxes	2,745.8	2,426.5	2,589.4
Income taxes (including royalty taxes, see Note 7)	1,237.9	966.3	1,105
Deferred income taxes	(63.5)	(21)	(51.5)
Net income before equity earnings of affiliate	1,571.4	1,481.2	1,535.9
Equity earnings of affiliate, net of income tax	6.4	10.7	12.3
Net income	1,577.8	1,491.9	1,548.2
Less: Net income attributable to the non-controlling interest	7.4	6.1	5.2
Net income attributable to SCC	$ 1,570.4	$ 1,485.8	$ 1,543
Per common share amounts attributable to SCC:
Net earnings-basic and diluted	$ 2.03	$ 1.92	$ 2
Weighted average shares outstanding-basic and diluted	773.1	773.1	773

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income and comprehensive income	$ 1,577.8	$ 1,491.9	$ 1,548.2
Other comprehensive income (loss) net of tax:
-Decrease (increase) in pension and other post-retirement benefits (net of income tax of $(1.9), $3.7 and $2.1, respectively)	1.7	(7.7)	(2.9)
Total other comprehensive income (loss)	1.7	(7.7)	(2.9)
Total comprehensive income	1,579.5	1,484.2	1,545.3
Comprehensive income attributable to the non-controlling interest	7.4	6.1	5.2
Comprehensive income attributable to SCC	$ 1,572.1	$ 1,478.1	$ 1,540.1

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Decrease (increase) in pension and other post-retirement benefits, income tax	$ (1.9)	$ 3.7	$ 2.1

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 2,183.6	$ 1,925.1
Short-term investments	410.8	80.7
Accounts receivable trade	1,068.9	832.9
Accounts receivable other (including related parties 2020- $23.3 and 2019 - $30.0)	67.7	78.9
Inventories	950.2	1,068.5
Prepaid taxes	104.8	172.4
Other current assets	29.2	26.2
Total current assets	4,815.2	4,184.7
Property and mine development, net	9,458.7	9,371
Ore stockpiles on leach pads	1,125	1,230.3
Intangible assets, net	143	148.4
Related parties receivable		59.5
Right-of-use assets	979	1,046.4
Deferred income tax	230	183.9
Equity method investment	114.3	111.9
Other non-current assets	81.3	71.3
Total assets	16,946.5	16,407.4
Current liabilities:
Current portion of long-term debt		399.8
Accounts payable (including related parties 2020- $104.3 and 2019- $86.4)	594.6	598.3
Accrued income taxes	340.9	116.3
Accrued workers' participation	247.8	174.9
Accrued interest	98.6	96
Lease liabilities current	70.6	68.6
Other accrued liabilities	32.3	22.6
Total current liabilities	1,384.8	1,476.5
Long-term debt, net of current portion	6,544.2	6,541
Lease liabilities	908.4	977.8
Deferred income taxes	159.4	178.3
Non-current taxes payable		0.7
Other liabilities and reserves	128.7	112.6
Asset retirement obligation	545	262.3
Total non-current liabilities	8,285.7	8,072.7
Commitments and contingencies (Note 13)
STOCKHOLDERS' EQUITY (NOTE 14)
Common stock par value $0.01; shares authorized, 2020 and 2019-2,000; shares issued, 2020 and 2019-884.6	8.8	8.8
Additional paid-in capital	3,441.5	3,424.9
Retained earnings	6,846.4	6,435.6
Accumulated other comprehensive income	(8.4)	(10.1)
Treasury stock, at cost, common shares	(3,063.5)	(3,048.9)
Total Southern Copper Corporation stockholders' equity	7,224.8	6,810.3
Non-controlling interest	51.2	47.9
Total equity	7,276	6,858.2
Total liabilities and equity	$ 16,946.5	$ 16,407.4

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Millions, $ in Millions	Dec. 31, 2020	Dec. 31, 2019
CONDENSED CONSOLIDATED BALANCE SHEETS
Accounts receivable other, related parties	$ 23.3	$ 30
Accounts payable, related parties	$ 104.3	$ 86.4
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	2,000	2,000
Common stock, shares issued	884.6	884.6

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
OPERATING ACTIVITIES
Net income	$ 1,577.8	$ 1,491.9	$ 1,548.2
Adjustments to reconcile net earnings to net cash provided from operating activities:
Depreciation, amortization and depletion	775.6	764.4	674.3
Equity earnings of affiliate, net of dividends received	(10.4)	(6.3)	(3.9)
Loss on foreign currency transaction effect	0.9	17.9	17.3
Benefit for deferred income taxes	(63.5)	(21)	(51.5)
Other, net	19.5	12	27
Change in operating assets and liabilities:
(Increase) decrease in accounts receivable	(236)	(10.5)	68.3
Decrease (increase) in inventories	223.6	(88.7)	(190.8)
Increase (decrease) in accounts payable and accrued liabilities	313.8	(184.9)	117.8
Decrease (increase) in other operating assets and liabilities	182.3	(62.9)	28.4
Net cash provided by operating activities	2,783.6	1,911.9	2,235.1
INVESTING ACTIVITIES
Capital expenditures	(592.2)	(707.5)	(1,121.4)
Purchase of short-term investments	(450.3)	(284.4)	(310.6)
Proceeds on sale of short-term investment	120.2	417.5	147.3
Other, net	6.5	0.4	(11.5)
Net cash used in investing activities	(915.8)	(574)	(1,296.2)
FINANCING ACTIVITIES
Repayments of debt	(400)
Proceeds from issuance of debt		987.3
Capitalization of debt issuance cost		(9.8)
Cash dividends paid to common stockholders	(1,159.6)	(1,236.9)	(1,082.3)
SCC shareholder derivative lawsuit - received from AMC		(36.5)
SCC shareholder derivative lawsuit - dividend paid		36.5
Distributions to non-controlling interest	(4.1)	(3.2)	(1.5)
Other, net	0.4	0.4	0.4
Net cash used in financing activities	(1,563.3)	(262.2)	(1,083.4)
Effect of exchange rate changes on cash and cash equivalents	(46)	4.8	(15.7)
Increase (decrease) in cash and cash equivalents	258.5	1,080.5	(160.2)
Cash and cash equivalents, at beginning of year	1,925.1	844.6	1,004.8
Cash and cash equivalents, at end of year	2,183.6	1,925.1	844.6
Cash paid during the year for:
Interest	383.5	356.7	356.7
Income taxes	1,037.1	1,138.7	1,155.3
Workers' participation	153.9	224.5	194
Supplemental schedule of non-cash operating, investing and financing activities:
Decrease (increase) in pension and other post-retirement benefits	1.7	(7.7)	(2.9)
Capital expenditures incurred but not yet paid	$ 32.2	$ 2.1	$ 37.7

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Millions	CAPITAL STOCK:	ADDITIONAL PAID-IN CAPITAL:	TREASURY STOCK:Southern Copper common shares	TREASURY STOCK:Parent Company (Grupo Mexico) common shares	TREASURY STOCK:	RETAINED EARNINGS:	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS):	STOCKHOLDERS' EQUITY	NON-CONTROLLING INTEREST	Total
Balance at beginning of year at Dec. 31, 2017		$ 3,373.3	$ (2,768.7)	$ (232.4)		$ 5,726.2	$ 0.5	$ 6,107.7	$ 41.7	$ 6,149.4
Increase (Decrease) in Stockholders' Equity
Net earnings						1,543			5.2	1,543
Dividends/distributions declared and paid						(1,082.3)			(1.5)
Used for corporate purposes			0.4
Other activity, including dividend, interest and foreign currency transaction effect				(18.9)
Other activity of the period		20.4
Other comprehensive income (loss)							(2.9)			(2.9)
Balance at end of year at Dec. 31, 2018	$ 8.8	3,393.7	(2,768.3)	(251.3)	$ (3,019.6)	6,186.9	(2.4)	6,567.4	45.4	6,612.8
Increase (Decrease) in Stockholders' Equity
Net earnings						1,485.8			6.1	1,485.8
Dividends/distributions declared and paid						(1,236.9)			(3.6)
SCC shareholder derivative lawsuit - received from AMC						36.5				36.5
SCC shareholder derivative lawsuit - dividend paid						(36.5)				(36.5)
Used for corporate purposes			0.4
Other activity, including dividend, interest and foreign currency transaction effect				(29.7)
Other activity of the period		31.2				(0.2)
Other comprehensive income (loss)							(7.7)			(7.7)
Balance at end of year at Dec. 31, 2019	8.8	3,424.9	(2,767.9)	(281)	(3,048.9)	6,435.6	(10.1)	6,810.3	47.9	6,858.2
Increase (Decrease) in Stockholders' Equity
Net earnings						1,570.4			7.4	1,570.4
Dividends/distributions declared and paid						(1,159.6)			(4.1)
Used for corporate purposes			0.4
Other activity, including dividend, interest and foreign currency transaction effect				(15)
Other activity of the period		16.6
Other comprehensive income (loss)							1.7			1.7
Balance at end of year at Dec. 31, 2020	$ 8.8	$ 3,441.5	$ (2,767.5)	$ (296)	$ (3,063.5)	$ 6,846.4	$ (8.4)	$ 7,224.8	$ 51.2	$ 7,276

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
RETAINED EARNINGS:
Dividends paid as cash dividend (in dollars per share)	$ 1.50	$ 1.60	$ 1.40

DESCRIPTION OF THE BUSINESS_

DESCRIPTION OF THE BUSINESS:	12 Months Ended
DESCRIPTION OF THE BUSINESS:	Dec. 31, 2020
DESCRIPTION OF THE BUSINESS:
DESCRIPTION OF THE BUSINESS:	NOTE 1—DESCRIPTION OF THE BUSINESS: The Company is a majority-owned, indirect subsidiary of Grupo Mexico S.A.B. de C.V. (“Grupo Mexico”). At December 31, 2020, Grupo Mexico through its wholly-owned subsidiary Americas Mining Corporation (“AMC”) owned 88.9% of the Company’s capital stock. The consolidated financial statements presented herein consist of the accounts of Southern Copper Corporation ("SCC", "Southern Copper" or the “Company”), a Delaware corporation, and its subsidiaries. The Company is an integrated producer of copper and other minerals, and operates mining, smelting and refining facilities in Peru and Mexico. The Company conducts its primary operations in Peru through a registered branch (the "Peruvian Branch" or “Branch” or “SPCC Peru Branch”). The Peruvian Branch is not a corporation separate from the Company. The Company's Mexican operations are conducted through subsidiaries. The Company also conducts exploration activities in Argentina, Chile, Ecuador, Mexico and Peru. COVID – 19 PANDEMIC Since the World Health Organization (“WHO”) declared the COVID-19 virus outbreak as a global pandemic, all the countries where the Company operates and conducts exploration activities, as well as the countries where its main customers and suppliers are located, have published health and safety rules and restrictions on individuals and business activities. As of December 31, 2020, the Company‘s production facilities in Mexico and Peru were working at approximately 98% of their production capacity. The Company has developed a rigorous COVID-19 emergency protocol. The Company has restarted exploration activities at all of its locations, except in Chile due to local restrictions. The Company restarted exploration activities in Ecuador and Argentina in September 2020 and at the end of the second quarter of 2020, respectively. The financial reporting process and the information required to prepare the Company’s financial statements suffered no interruption and the financial statements were prepared without restrictions or difficulties. SCC´s Corporate Crisis Committee as well as its Crisis Committees in Mexico and Peru continue to closely monitor the impact of the pandemic and to analyze and quickly resolve any issues that may arise. As of December 31, 2020, there were no major delays in the supply of materials and services critical for the operations and sales. Also, shipments and collections have registered no known major delays. After completing the first stage of its capital programs at Buenavista in Mexico and Toquepala in Peru, the Company currently does not have major capital expenditures commitments (see Note 13 - Commitments and Contingencies). The Company paid the first tranche of its 2010 bonds of $400 million on April 15, 2020. The Company has no other major debt maturity until 2022. The Company performed a qualitative analysis and as of December 31, 2020 identified no indicators of impairment. As the Company reported, the results of its impairment sensitivity analysis showed projected discounted cash flows in excess of the carrying amounts of long-lived assets by margins ranging from 1.3 to 4.3 times such carrying amount. This analysis included a stress test using a copper price assumption of $2.00 per pound and a molybdenum price assumption of $4.00 per pound.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:	Dec. 31, 2020
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:	NOTE 2—SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES: Principles of consolidation— The consolidated financial statements include the accounts of subsidiaries of which the Company has voting control, in accordance with Accounting Standards Codification (“ASC”) 810 Consolidation Use of estimates— The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Significant items subject to such estimates and assumptions include the carrying value of ore reserves that are the basis for future cash flow estimates and amortization calculations; environmental reclamation, closure and retirement obligations; estimates of recoverable copper in mill and leach stockpiles; asset impairments (including estimates of future cash flows); unrecognized tax benefits; valuation allowances for deferred tax assets; and fair value of financial instruments. Management bases its estimates on the Company's historical experience and on various other assumptions that are believed to be reasonable under the circumstances. Actual results could differ from those estimates. Revenue recognition— The Company accounts for a contract with a customer when there is a legally enforceable contract between the Company and the customer, the rights of the parties are identified, the contract has commercial substance, and collectability of the contract consideration is probable. The Company's revenues are measured based on consideration specified in the contract with each customer. Disclosures regarding disaggregation of revenues and contract balances are disclosed within Note 18 "Segment and related information". The Company’s marketing strategy and annual sales planning emphasize developing and maintaining long-term customer relationships. Generally, 80% to 90% of the Company’s metal production is sold under annual or longer-term contracts, which specify a volume of mineral to be sold over a stated period and delivery schedule; the price at which mineral will be sold at each delivery date is generally determined by the weekly or monthly average rate of the commodity published by major metal exchanges at specific dates stipulated within each contract. The Company considers each contract to be a single performance obligation, represented by the delivery of a series of distinct goods that are substantially the same, with the same pattern of transfer to the Company’s customers. The Company concluded this as, based on the nature of its contracts, customers receive the benefit of mineral sold as it is shipped per the terms of the contracts at each contractual delivery date. Likewise, each shipment of product represents the same measure of progress as other shipments within the contract. Accordingly, the Company recognizes revenues for each contract over the period of time in which the specified quantity of mineral is delivered. In doing so, the Company considers that it has a right to consideration from its customers in an amount that corresponds directly to the value transferred to those customers that being the quantity of mineral delivered at the price per unit delivered. Accordingly, the Company recognizes revenue at the amount to which it has the right to invoice (the invoice practical expedient), as it believes that this method is a faithful depiction of the transfer of goods to its customers. For contracts with a term greater than one year, the Company is unable to disclose an allocation of the transaction price to the remaining unsatisfied performance obligation, given that unit prices of mineral sold are determined by published commodity prices at specified dates within the contract. The volume of mineral to be delivered after the first year of the contract is subject to annual volume negotiations in accordance with the terms of the contract. As of December 31, 2020, the Company has long-term contracts with promises to deliver in 2021 for a total of 208,000 metric tons of copper concentrate, 48,000 metric tons of copper cathodes, 43,329 tons of molybdenum concentrate and 325,700 tons of sulfuric acid. This is an estimate that will vary in 2022 and 2023 based on the negotiations with the customers as mentioned above. The remainder of the Company’s revenues, including its by-product revenues, are generated by spot sales that are recognized at a point in time. Under both sales models, revenue is recognized when or as the performance obligations are satisfied, when the Company transfers control of the goods and title passes to the customer. Considering the International Commercial Terms (Incoterms) utilized by the Company, control is transferred generally upon the completion of loading the material at the point of origin. This is the point at which the customer obtains legal title to the product as well as the ability to direct the use of and obtain substantially all of the remaining benefits of ownership of the asset. Additionally, payment is generally due upon the delivery of the shipping and title documents at the point of origin, customers typically have 30 days to remit payment. Copper and non-copper revenues are measured based on the monthly average of prevailing commodity prices according to the terms of the contracts. The Company provides allowances for doubtful accounts based upon historical bad debt and claims experience and periodic evaluation of specific customer accounts. Substantially all of the Company’s sales are made under carriage and insurance paid to, or cost, insurance and freight Incoterms, whereby the Company is responsible for providing shipping and insurance after control of the inventory has been transferred to the customer. According to the terms of the Company’s contracts, these services are not distinct within the context of the contract, and they are not separately identifiable from the other promises within the contract. Additionally, it is the Company policy and it has a long-standing history of providing shipping and insurance services to its customers. Accordingly, shipping and insurance are not considered separate performance obligations. The related costs of shipping and insurance are presented within the cost of sales line in the accompanying consolidated statements of income. Furthermore, the Company considered the impact of the shipping and insurance services on the determination of when control is transferred to its customers. It has concluded that the terms of these services do not impact its customers’ ability to sell, pledge, or otherwise use the products in shipment. Also, there is a small likelihood and minimal history of lost or damaged goods during shipment. Considering these factors, combined with the other indicators of control previously mentioned, the Company has concluded that these services do not impact the determination that control is transferred at the point of origin. For certain of the Company’s sales of copper and molybdenum products, customer contracts allow for pricing based on a month subsequent to shipping, in most cases within the following three months and occasionally in some cases a few additional months. In such cases, revenue is recorded at a provisional price at the time of shipment. The provisionally priced copper sales are adjusted to reflect forward LME or COMEX copper prices at the end of each month until a final adjustment is made to the price of the shipments upon settlement with customers pursuant to the terms of the contract. In the case of molybdenum sales, for which there are no published forward prices, the provisionally priced sales are adjusted to reflect the market prices at the end of each month until a final adjustment is made to the price of the shipments upon settlement with customers pursuant to the terms of the contract. These provisional pricing arrangements are accounted for separately from the contract as an embedded derivative instrument under ASC 815-30 “Derivatives and Hedging—Cash Flow Hedges.” The Company sells copper in concentrate, anode, blister and refined form at industry standard commercial terms. Net sales include the invoiced value of copper, zinc, silver, molybdenum, sulfuric acid and other metals and the corresponding fair value adjustment of the related forward contract of copper and molybdenum. Disclosure regarding adjustments to sales for provisionally priced contracts is disclosed within Note 18 “Segment and related information”. Cash and cash equivalents— Cash and cash equivalents include bank deposits, certificates of deposit and short-term investment funds with original maturities of three months or less at the date of purchase. The carrying value of cash and cash equivalents approximates fair value. Short-term investments— The Company accounts for short-term investments in accordance with ASC 320-10 “Investments Debt and Equity Securities-Recognition.” The Company determines the appropriate classification of all short-term investments as held-to-maturity, available-for-sale or trading at the time of purchase and re-evaluates such classifications as of each balance sheet date. Unrealized gains and losses on available-for-sale investments, net of taxes, are reported as a component of accumulated other comprehensive income (loss) in stockholders’ equity, unless such loss is deemed to be other than temporary. Inventories— The Company principally produces copper and, in the production process, obtains several by-products, including molybdenum, silver, zinc, sulfuric acid and other metals. Metal inventories, consisting of work-in-process and finished goods, are carried at the lower of average cost or net realizable value (NRV). Costs of work-in-process inventories and finished goods mainly include power, labor, fuel, operating and repair materials, depreciation, amortization, depletion, and other necessary costs related to the extraction and processing of ore, including mining, milling, concentrating, smelting, refining, leaching and chemical processing. Costs incurred in the production of metal inventories exclude general and administrative costs. Once molybdenum, silver, zinc and other by-products are identified, they are transferred to their respective production facilities and the incremental cost required to complete production is assigned to their inventory value. Work-in-process inventories represent materials that are in the process of being converted into a saleable product. Conversion processes vary depending on the nature of the copper ore and the specific mining operation. For sulfide ores, processing includes milling and concentrating and results in the production of copper and molybdenum concentrates. Finished goods include saleable products (e.g., copper concentrates, copper anodes, copper cathodes, copper rod, molybdenum concentrate and other metallurgical products). Supplies inventories are carried at the lower of average cost or net realizable value (NRV). Long-term inventory-Ore stockpiles on leach pads. The leaching process is an integral part of the mining operations carried out at the Company’s open-pit mines. The Company capitalizes the production cost of leachable material at its Toquepala, La Caridad and Buenavista mines, recognizing it as inventory. This cost includes mining and haulage costs incurred to deliver ore to leach pads, depreciation, amortization, depletion and site overhead costs. The estimates of recoverable mineral content contained in the leaching dumps are supported by engineering studies. As the production cycle of the leaching process is significantly longer than the conventional process of concentrating, smelting and electrolytic refining, the Company includes current leach inventory (included in work-in-process inventories) and long-term leach inventory on its balance sheet. On January 1, 2020, the Company aligned its capitalization method for its Peruvian and Mexican operations to capitalize based on the allocation of copper content recoverable between ore and leach material. In addition, inventory consumption is now valued at the average unit cost, instead of the declining percentages of recovery method used previously. As a result of these changes, during 2020 the value of capitalized material decreased by $196.4 million and consumption decreased by $29.3 million when compared to the previous capitalization method. Management has evaluated ASC 250-10 and considered appropriate guidance to conclude that the aforementioned classifies as a change in accounting estimate, and therefore should affect accounting books prospectively. Management believes that this new method will result in a more accurate valuation of this material. Property— Property is recorded at acquisition cost, net of accumulated depreciation and amortization. Cost includes major expenditures for improvements and replacements, which extend useful lives or increase capacity and interest costs associated with significant capital additions. Maintenance, repairs, normal development costs at existing mines and gains or losses on assets retired or sold are reflected in earnings as incurred. Buildings and equipment are depreciated on the straight-line method over estimated lives from two Mine development — Mine development includes primarily the cost of acquiring land rights to an exploitable ore body, pre-production stripping costs at new mines that are commercially exploitable, costs associated with bringing new mineral properties into production, and removal of overburden to prepare unique and identifiable areas outside the current mining area for such future production. Mine development costs are amortized on a unit of production basis over the remaining life of the mines. Diverse practices exist in the mining industry relative to the treatment of drilling and other related costs to delineate new ore reserves. The Company follows the practices outlined in the next two paragraphs in its treatment of drilling and related costs. Drilling and other associated costs incurred in the Company's efforts to delineate new resources, whether near-mine or Greenfield are expensed as incurred. These costs are classified as mineral exploration costs. Once the Company determines through feasibility studies that proven and probable reserves exist and that the drilling and other associated costs embody a probable future benefit that involves a capacity, singly or in combination with other assets, to contribute directly or indirectly to future net cash inflow, then the costs are classified as mine development costs. These mine development costs incurred prospectively to develop the property are capitalized as incurred, until the commencement of production, and are amortized using the units of production method over estimated life of the ore body. During the production stage, drilling and other related costs incurred to maintain production are included in production cost in the period in which they are incurred. Drilling and other related costs incurred in the Company’s efforts to delineate a major expansion of reserves at an existing production property are expensed as incurred. Once the Company determines through feasibility studies that proven and probable incremental reserves exist and that the drilling and other associated costs embody a probable future benefit that involves a capacity, singly or in combination with other assets, to contribute directly or indirectly to future net cash inflow, then the costs are classified as mine development costs. These incremental mine development costs are capitalized as incurred, until the commencement of production and amortized using the units of production method over the estimated life of the ore body. A major expansion of reserves is one that increases total reserves at a property by approximately 10% or more. For the years ended December 31, 2020, 2019 and 2018, the Company did not capitalize any drilling and related costs. Asset retirement obligations (reclamation and remediation costs)— The fair value of a liability for asset retirement obligations is recognized in the period in which the liability is incurred. The liability is measured at fair value and is adjusted to its present value in subsequent periods as accretion expense is recorded. The corresponding asset retirement costs are capitalized as part of the carrying value of the related long-lived assets and depreciated over the asset's useful life. Intangible assets— Intangible assets include primarily the excess amount paid over the book value for investment shares, which are presented as mining concessions, and mining and engineering development studies. Intangible assets are carried at acquisition costs, net of accumulated amortization and are amortized principally on a unit of production basis over the estimated remaining life of the mines. Intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable. Debt issuance costs— Debt issuance costs related to a recognized debt liability are presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with the treatment of a debt discount. Ore reserves— The Company periodically reevaluates estimates of its ore reserves, which represent the Company’s estimate as to the amount of unmined copper remaining in its existing mine locations that can be produced and sold at a profit. Such estimates are based on engineering evaluations derived from samples of drill holes and other openings, combined with assumptions about copper market prices and production costs at each of the respective mines. The Company updates its estimate of ore reserves at the beginning of each year. In this calculation, the Company uses current metal prices which are defined as the average metal price over the preceding three years. The current price per pound of copper, as defined, was $2.816, $2.818 and $2.642 at the end of 2020, 2019 and 2018, respectively. The ore reserve estimates are used to determine the amortization of mine development and intangible assets. Once the Company determines through feasibility studies that proven and probable reserves exist and that drilling and other associated costs embody a probable future benefit that involves a capacity, singly or in combination with other assets, to contribute directly or indirectly to future net cash inflow, then the costs are classified as mine development costs and the Company discloses the related ore reserves. Exploration— Tangible and intangible costs incurred in the search for mineral properties are charged against earnings when incurred. Income taxes— Provisions for income taxes are based on taxes payable or refundable for the current year and deferred taxes on temporary differences between the amount of taxable income and pretax financial income and between the tax bases of assets and liabilities and their reported amounts in the financial statements. Deferred tax assets and liabilities are included in the financial statements at currently enacted income tax rates applicable to the period in which the deferred tax assets and liabilities are expected to be realized and settled as prescribed in ASC 740 “Income taxes.” As changes in tax laws or rates are enacted, deferred tax assets and liabilities are adjusted through the provision for income taxes. Deferred income tax assets are reduced by any benefits that, in the opinion of management, are more likely not to be realized. The Company’s operations involve dealing with uncertainties and judgments in the application of complex tax regulations in multiple jurisdictions. The final taxes paid are dependent upon many factors, including negotiations with tax authorities in various jurisdictions and resolution of disputes arising from federal, state, and international tax audits. The Company recognizes potential liabilities and records tax liabilities for anticipated tax audit issues in the U.S. and other tax jurisdictions based on its estimate of whether, and the extent to which, additional taxes will be due. The Company follows the guidance of ASC 740 “Income taxes” to record these liabilities. (See Note 7 “Income taxes” of the consolidated financial statements for additional information). The Company adjusts these reserves in light of changing facts and circumstances; however, due to the complexity of some of these uncertainties, the ultimate resolution may result in a payment that is materially different from the Company’s current estimate of the tax liabilities. If its estimate of tax liabilities proves to be less than the ultimate assessment, an additional charge to expense would result. If payment of these amounts ultimately proves to be less than the recorded amounts, the reversal of the liabilities would result in tax benefits being recognized in the period when the Company determines the liabilities are no longer necessary. The Company classifies income tax-related interest and penalties as income taxes in the financial statements, as well as interest and penalties, if any, related to unrecognized tax benefits. Foreign exchange— The Company’s functional currency is the U.S. dollar. As required by local law, both the Peruvian Branch and Minera Mexico maintain their books of accounts in Peruvian soles and Mexican pesos, respectively. Foreign currency assets and liabilities are remeasured into U.S. dollars at current exchange rates, except for non-monetary items such as inventory, property, intangible assets and other assets which are remeasured at historical exchange rates. Revenues and expenses are generally translated at actual exchange rates in effect during the period, except for those items related to balance sheet amounts that are remeasured at historical exchange rates. Gains and losses from foreign currency remeasurement are included in earnings of the period. Gains and (losses) resulting from foreign currency transactions are included in "Cost of sales (exclusive of depreciation, amortization and depletion)." Asset impairments - The Company evaluates long-term assets when events or changes in economic circumstances indicate that the carrying amount of such assets may not be recoverable. These evaluations are based on business plans that are prepared using a time horizon that is reflective of the Company’s expectations of metal prices over its business cycle. The Company is currently using a long-term average copper price and an average molybdenum price for impairment tests, reflective of what the Company believes is the lower level of the current price environment. The results of its impairment tests using these long-term copper and molybdenum prices show no impairment in the carrying value of their assets. In recent years testing using assumptions for long-term average prices have resulted in stricter evaluation for impairment analysis than would the higher three year average prices for copper and molybdenum prices. Should this situation reverse in the future with three - - Other comprehensive income— Comprehensive income represents changes in equity during a period, except those resulting from investments by owners and distributions to owners. During the fiscal years ended December 31, 2020, 2019 and 2018, the components of "other comprehensive income (loss)" were, the unrecognized gain (loss) on employee benefit obligations and foreign currency translation adjustments. Business segments- Company management views Southern Copper as having three reportable segments and manages it on the basis of these segments. The segments identified by the Company are: 1) the Peruvian operations, which include the two open-pit copper mines in Peru and the plants and services supporting such mines, 2) the Mexican open-pit copper mines, which include La Caridad and Buenavista mine complexes and their supporting facilities and 3) the Mexican underground mining operations, which include five underground mines that produce zinc, lead, copper, silver and gold, a coal mine and a zinc refinery. Please see Note 18 “Segments and Related Information.” The Chief Operating Decision Maker of the Company focuses on operating income as measure of performance to evaluate different segments, and to make decisions to allocate resources to the reported segments. This is a common measure in the mining industry. Leases - The Company adopted FASB ASC 842, Leases, effective January 1, 2019. The Company determined if a contract is or contained a lease at its inception. The Company evaluated if a contract gave the right to obtain substantially all of the economic benefits from use of an identified asset and the right to direct the use of the asset, in order to determine if a contract contained a lease. All of the Company’s existing lease contracts are operating lease contracts. For these leases, the Company recognized right-of-use assets and the corresponding operating lease liabilities on its consolidated balance sheet. Right-of-use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent an obligation by the Company to make lease payments which arise from the lease. Lease right-of-use assets and liabilities are recognized at the inception date based on the present value of lease payments over the lease term. As the Company’s lease contracts do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at the inception date in order to determine the present value of lease payments. Lease expense for lease payments is recognized on a straight-line basis over the lease term, in the cost of sales and operating expenses. The Company elected the transition approach whereby it applied the new leases standard at the adoption date and recognized a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. The Company elected the short-term lease recognition exemption (short-term lease practical expedient) by class of underlying asset (which results in off-balance-sheet accounting for the lease). ADOPTION OF CREDIT LOSSES STANDARD In June 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-13: “Financial Instruments – Credit Losses (Topic 326)”. This ASU was adopted on January 1, 2020. Prior to adopting this ASU, the Company applied an impairment methodology for accounts receivable arising from revenue transactions within the scope of ASC 606 that is consistent with the provision matrix model contemplated in the new standard. In addition, the new disclosure requirements do not apply to such trade receivables because the collection periods in all cases are less than one year. The Company’s accounts receivable from related parties under common control are excluded from the scope of this ASU. Accordingly, the adoption of this ASU did not have a material impact on the Company’s financial statements or related disclosures.

SHORT-TERM INVESTMENTS_

SHORT-TERM INVESTMENTS:	12 Months Ended
SHORT-TERM INVESTMENTS:	Dec. 31, 2020
SHORT-TERM INVESTMENTS:
SHORT-TERM INVESTMENTS:	NOTE 3—SHORT-TERM INVESTMENTS: Short-term investments were as follows ($ in millions): At December 31, 2020 2019 Trading securities $ 410.2 $ 80.0 Weighted average interest rate 0.4 % 2.0 % Available-for-sale $ 0.6 $ 0.7 Weighted average interest rate 0.7 % 0.7 % Total $ 410.8 $ 80.7 Trading securities consist of bonds issued by public companies and are publicly traded. Each financial instrument is independent of the others. The Company has the intention to sell these bonds in the short-term. Available-for-sale investments consist of securities issued by public companies. Each security is independent of the others and, as of December 31, 2020 and 2019, included corporate bonds and asset and mortgage backed obligations. As of December 31, 2020 and 2019, gross unrealized gains and losses on available-for-sale securities were not material. Related to these investments the Company earned interest, which was recorded as interest income in the consolidated statement of earnings. Also the Company redeemed some of these securities and recognized gains (losses) due to changes in fair value, which were recorded as other income (expense) in the consolidated statement of earnings. The following table summarizes the activity of these investments by category (in millions): Years ended December 31, 2020 2019 Trading: Interest earned $ 0.7 $ 0.6 Unrealized gain (loss) at the end of the period $ () $ () Available-for-sale: Interest earned () () Investment redeemed $ 0.1 $ — (*) Less than $0.1 million At December 31, 2020 and 2019, contractual maturities of the available-for-sale debt securities are as follows (in millions): 2020 2019 One year or less $ — $ — Maturing after one year through five years — — Maturing after five years through ten years — — Due after 10 years 0.6 0.7 Total debt securities $ 0.6 $ 0.7

INVENTORIES_

INVENTORIES:	12 Months Ended
INVENTORIES:	Dec. 31, 2020
INVENTORIES:
INVENTORIES:	NOTE 4—INVENTORIES: At December 31, (in millions) 2020 2019 Inventory, current: Metals at average cost: Finished goods $ 50.8 $ 87.2 Work-in-process 248.9 259.7 Ore stockpiles on leach pads 298.5 358.4 Supplies at average cost 352.0 363.2 Total current inventory $ 950.2 $ 1,068.5 Inventory, long-term: Ore stockpiles on leach pads $ 1,125.0 $ 1,230.3 Total leaching costs added as long-term inventory of ore stockpiles in leach pads amounted to $194.0 million, $469.0 million and $506.6 million in 2020, 2019 and 2018, respectively. Long-term leaching inventories recognized as cost of sales amounted to $359.1 million, $385.8 million and $299.4 million in 2020, 2019 and 2018, respectively.

PROPERTY_

PROPERTY:	12 Months Ended
PROPERTY:	Dec. 31, 2020
PROPERTY:
PROPERTY:	NOTE 5—PROPERTY: At December 31, (in millions) 2020 2019 Buildings and equipment $ 15,561.9 $ 15,016.1 Construction in progress 1,481.6 1,294.8 Mine development 272.8 267.5 Mineral assets 83.2 83.2 Land, other than mineral 235.8 200.1 Total property 17,635.3 16,861.7 Accumulated depreciation, amortization and depletion (8,176.6) (7,490.7) Total property and mine development, net $ 9,458.7 $ 9,371.0 Depreciation and depletion expense for the years ended December 31, 2020, 2019 and 2018, amounted to $766.4 million, $759.9 million and $668.9 million, respectively.

INTANGIBLE ASSETS_

INTANGIBLE ASSETS:	12 Months Ended
INTANGIBLE ASSETS:	Dec. 31, 2020
INTANGIBLE ASSETS:
INTANGIBLE ASSETS:	NOTE 6—INTANGIBLE ASSETS: At December 31, (in millions) 2020 2019 Mining concessions $ 121.2 $ 121.2 Mine engineering and development studies 19.8 19.8 Software 60.6 55.9 201.6 196.9 Accumulated amortization: Mining concessions (38.6) (38.0) Mine engineering and development studies (17.2) (16.3) Software (44.7) (36.1) (100.5) (90.4) Goodwill 41.9 41.9 Intangible assets, net $ 143.0 $ 148.4 Amortization of intangibles for the years ended December 31, 2020, 2019 and 2018, amounted to $9.2 million, $4.5 million and $5.4 million, respectively. Estimated amortization is as follows: Estimated amortization expense (in millions): 2021 $ 7.7 2022 5.2 2023 5.2 2024 4.3 2025 3.0 Total 2021 - 2025 $ 25.4 Average annual $ 5.1 Goodwill includes $17.0 million generated in 1997 as a result of purchasing a third party interest in the Buenavista mine. It also includes $24.9 million representing the amount of the purchase price in excess of the fair value of the net assets acquired from El Pilar mine. This goodwill is attributable to future benefits that the Company expects to realize from the mine and will not be deductible for income tax purposes.

INCOME TAXES_

INCOME TAXES:	12 Months Ended
INCOME TAXES:	Dec. 31, 2020
INCOME TAXES:
INCOME TAXES:	NOTE 7—INCOME TAXES: Since March 2009, Grupo Mexico, through its wholly-owned subsidiary AMC, owns an interest in excess of 80% of SCC. Accordingly, SCC’s results are included in the consolidated results of the Grupo Mexico subsidiary for U.S. federal income tax reporting. SCC provides current and deferred income taxes, as if it were filing a separate U.S. federal income tax return. The introduction of the Global Intangible Low Tax Income or GILTI for tax years beginning in 2018 impose a tax on foreign income in excess of a deemed return on tangible assets of foreign corporations. For 2018-2020, there was no U.S. tax liability from the GILTI inclusion. The Company does not anticipate a tax on GILTI in the future because of increased fixed asset amounts and given the Mexican tax rate of 30%, no U.S. deferred taxes would be recorded. Accordingly, the Company has elected that if GILTI were to apply in the future, a current period expense would be recorded when incurred. Also introduced with 2017 U.S tax reform and applicable to years 2018 and after is the Base Erosion Anti-Abuse Tax (BEAT). BEAT is a 5% minimum tax for tax year 2018, 10% for the years 2019 through 2025 and 12.5% in years thereafter. It is calculated on a base equal to the Company’s income determined without the tax benefit arising from base erosion payments. The Company did not incur a BEAT liability in 2018, 2019 and 2020 since it has met the safe harbor rule that provides a Company not to be subject to the BEAT if related party payments from the U.S. to foreign entities does not exceed 3% of expenses excluding cost of goods sold. The Company must continue to analyze applicability of the BEAT provisions on a yearly basis. The components of the provision for income taxes for the three years ended December 31, 2020, are as follows: (in millions) 2020 2019 2018 U.S. federal and state: Current $ — $ — $ 2.6 Deferred — — (13.0) Uncertain tax positions — (1.3) — — (1.3) (10.4) Foreign (Peru and Mexico): Current 1,237.9 966.3 1,102.4 Deferred (63.5) (30.1) (38.5) Uncertain tax positions — 10.4 — 1,174.4 946.6 1,063.9 Total provision for income taxes $ 1,174.4 $ 945.3 $ 1,053.5 The source of income is as follows: (in millions) 2020 2019 2018 Earnings by location: U.S. $ (15.3) $ (1.9) $ (2.3) Foreign Peru 723.9 513.0 441.8 Mexico 2,037.2 1,915.4 2,149.9 2,761.1 2,428.4 2,591.7 Earnings before taxes on income $ 2,745.8 $ 2,426.5 $ 2,589.4 The reconciliation of the statutory income tax rate to the effective tax rate for the three years ended December 31, 2020, is as follows (in percentage points): 2020 2019 2018 Expected tax at U.S. statutory rate 21.0 % 21.0 % 21.0 % Foreign tax at other than statutory rate, net of foreign tax credit benefit (1) 13.7 14.0 13.9 Percentage depletion (2.2) (2.7) (2.1) Other permanent differences 0.1 0.1 0.4 Change in 2017 valuation allowance on U.S. deferred tax assets, foreign tax credits and U.S. tax effect on Peruvian deferred taxes — — 7.5 Additional valuation allowance on 2018 U.S. deferred tax assets, foreign tax credits and U.S. tax effect on Peruvian deferred taxes 8.9 10.1 1.0 Decrease in 2017 U.S. deferred tax asset due to tax rate changes — — (0.2) U.S. one time transition tax on accumulated foreign earnings — — 0.4 Increase (decrease) in unrecognized tax benefits for uncertain tax positions (0.1) (2.1) — Amounts (over) / under provided in prior years (0.1) (1.1) (1.3) Other 1.5 (0.3) 0.1 Effective income tax rate 42.8 % 39.0 % 40.7 % (1) Foreign tax at other than statutory rates, net of foreign tax credit benefit, also includes the effects of permanent differences in Peru and Mexico, that are determined at the local statutory rate. The Company files income tax returns in three jurisdictions, Peru, Mexico and the United States. For the three years presented above, the statutory income tax rate for Mexico was 30% and the United States tax rate was 21%. The Peruvian tax rate was 29.5% for the three years presented above. While the largest components of income taxes are the Peruvian and Mexican taxes, the Company is a domestic U.S. entity. Therefore, the rate used in the above reconciliation is the U.S. statutory rate. For all of the years presented, both the Peruvian branch and Minera Mexico filed separate tax returns in their respective tax jurisdictions. Although the tax rules and regulations imposed in the separate tax jurisdictions may vary significantly, similar permanent items exist, such as items which are nondeductible or nontaxable. Some permanent differences relate specifically to SCC such as the allowance in the United States for percentage depletion. Deferred taxes include the U.S., Peruvian and Mexican tax effects of the following types of temporary differences and carryforwards: At December 31, (in millions) 2020 2019 Assets: Inventories $ 62.4 $ 55.7 Capitalized exploration expenses 13.0 14.0 U.S. foreign tax credit carryforward, net of FIN 48 liability 974.1 731.8 U.S. tax effect of Peruvian deferred tax liability 111.2 131.3 Provisions 169.5 145.0 Mexican tax on consolidated dividends — 9.0 Deferred workers participation 37.8 24.7 Accrued salaries, wages and vacations 8.5 10.0 Sales price adjustment (PUI) (5.8) 3.0 Social responsibility expenses 4.3 2.1 Deferred charges 41.8 14.5 Valuation allowance on U.S. deferred tax assets, foreign tax credits and U.S. tax effect on Peruvian deferred (1,343.2) (1,097.0) Other 19.5 9.9 Total deferred tax assets 93.1 54.0 At December 31, (in millions) 2020 2019 Liabilities: Property, plant and equipment (17.2) (45.4) Other (5.3) (3.0) Total deferred tax liabilities (22.5) (48.4) Total net deferred tax (liabilities) / assets $ 70.6 $ 5.6 The valuation allowance increased by $246.2 million over 2019’s level, which was primarily due to the valuation of unutilized Foreign Tax Credits generated in 2020 and the valuation of Foreign Tax Credits carried forward from prior years. The Peru branch operations are taxed in the U.S. as a flow through entity to SCC. Prior to 2017 U.S. Tax Reform, the U.S. corporate income tax rate was 35% on the Peru earnings, which enabled the company to use more currently generated foreign tax credits. Since tax reform reduced the U.S. tax rate to 21%, there is less U.S. income tax to absorb currently generated FTC’s or carryforwards. Additionally, allowable expenses in the U.S. for percentage depletion and U.S. sourced interest expense on debt reduced the branch income subject to U.S. tax, further limiting utilization of foreign tax credits. U.S. Tax Matters— As of December 31, 2020, the Company considers its ownership of the stock of Minera Mexico to be essentially permanent in duration. As of December 31, 2020, $1,297.3 million of the Company´s total cash, cash equivalents and short-term investments of $2,594.4 million were held by foreign subsidiaries. The cash, cash equivalents and short-term investments maintained in our foreign operations are generally used to cover local operating and investment expenses. The Company has determined that as of December 31, 2020, a deferred tax asset of $0.2 billion exists with respect to its investment in foreign subsidiaries. Tax accounting guidance provided in ASC 740 requires this asset to be recognized only if the basis difference will reverse in the foreseeable future. Management has no plans that would result in the reversal of this temporary difference and consequently no deferred tax asset has been recorded. Future dividends from these subsidiaries are no longer subject to federal income tax in the U.S., and the Company incurs no state income tax liability. Additionally, there are no withholding taxes due to the tax treaty between the United States and Mexico. Earnings from the Company’s Peruvian branch are not subject to transition taxes given that they are taxed in the United States on a current basis. At December 31, 2020, there were $1,040.0 million of foreign tax credits available for carryback or carryforward. These credits have a one-year carryback and a ten-year carryforward period and can only be used to reduce U.S. income tax on foreign earnings. There were no other unused U.S. tax credits at December 31, 2020. These credits will expire if not utilized by the end of the years listed below: Year Amount 2023 39.4 2024 102.0 2025 189.5 2026 107.0 2027 — 2028 159.6 2029 204.9 2030 237.6 Total $ 1,040.0 These foreign tax credits are presented above on a gross basis and have not been reduced here for any unrecognized tax benefits. These foreign tax credits have been adjusted to include the 2016 Net Operating Loss carryback in the U.S. jurisdiction, increasing foreign tax credits by approximately $15.9 million. In accordance with ASC 740 the Company has recorded $66.1 million for an unrecognized tax benefit as an offset to the Company’s deferred tax asset for foreign tax credits. The remaining foreign tax credits of $973.9 million are being re-valued to zero at December 31, 2020. It is the opinion of management that with the reduction in the U.S. corporate tax rate to 21% and considering the corporate tax rates in Mexico of 30% and in Peru at 29.5%, it is unlikely the excess foreign tax credits can be utilized. Additionally, foreign dividends will no longer be taxed in the U.S., thereby reducing the U.S. tax on the foreign source income that the credits can be used to offset. Peruvian Tax Matters— Royalty mining charge: Peruvian special mining tax: Mexican Tax Matters— In 2013, the Mexican Congress enacted tax law changes that became effective on January 1, 2014. Among other effects, the amounts that Minera Mexico recorded during 2019 and paid in 2020 were: ● Mining royalty at the rate of 7.5% on taxable earnings before taxes: $60.1 million. ● Additional royalty of 0.5% over gross income from sales of gold, silver and platinum: $0.9 million. On December 09, 2019, the Federal Revenue Law for fiscal year 2020, was published in the Federal Official Gazette, effective as of January 1, 2020. The main tax matters are reported as follows: Income tax changes - Interest expense limitation based on profit levels: Accounting for Uncertainty in Income Taxes— The total amount of unrecognized tax benefits in 2020, 2019 and 2018, was as follows (in millions): 2020 2019 2018 Unrecognized tax benefits, opening balance $ 58.4 $ 214.5 $ 214.5 Gross increases—tax positions in prior period — (7.5) — Gross increases—current-period tax positions 7.7 (4.2) — Decreases related to settlements with taxing authorities — (144.4) — 7.7 (156.1) — Unrecognized tax benefits, ending balance $ 66.1 $ 58.4 $ 214.5 The amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate was zero at December 31, 2020 for unrecognized tax benefits in the Peruvian jurisdiction. Any recognition of unrecognized tax benefits within the U.S. jurisdiction would not affect the effective tax rate as long as the Company continues to value U.S. deferred tax assets including foreign tax credits. The Company has no unrecognized Mexican tax benefits. The Company’s U.S. IRS audit of 2014 -2016 commenced in 2019 and is expected to settle in the first half of 2021. As of December 31, 2020, the Company’s liability for uncertain tax positions did not include accrued interest and penalties in the U.S. jurisdiction. As of December 31, 2019 and December 31, 2018 the Company’s liability for uncertain tax positions included Peruvian accrued interest and penalties of $10.5 and $1.9 million, respectively. The following tax years remain open to examination and adjustment in the Company’s three major tax jurisdictions: Peru: 2014 and all subsequent years U.S.: 2014 and all subsequent years Mexico: 2015 and all subsequent years Management does not expect that any of the open years will result in a cash payment within the U.S. jurisdiction in the upcoming twelve months ending December 31, 2021. Additionally, the Company expects that $0.6 million in cash payments in the Peruvian jurisdiction will be paid within the upcoming twelve months ending December 31, 2021. The Company’s reasonable expectations about future resolutions of uncertain items did not materially change during the year ended December 31, 2020.

WORKERS' PARTICIPATION_

WORKERS' PARTICIPATION:	12 Months Ended
WORKERS' PARTICIPATION:	Dec. 31, 2020
WORKERS' PARTICIPATION:
WORKERS' PARTICIPATION:	NOTE 8—WORKERS’ PARTICIPATION: The Company's operations in Peru and Mexico are subject to statutory workers' participation. In Peru, the provision for workers' participation is calculated at 8% of pre-tax earnings. The current portion of this participation, which is accrued during the year, is based on the Peruvian Branch's taxable income and is distributed to workers following determination of final results for the year. The annual amount payable to an individual worker is capped at the worker’s salary for an 18 month period. Amounts determined in excess of the 18 months of worker’s salary is no longer made as a payment to the worker and is levied first for the benefit of the “Fondo Nacional de Capacitacion Laboral y de Promocion del Empleo” (National Workers’ Training and Employment Promotion Fund) until this entity receives from all employers in its region an amount equivalent to 2,200 Peruvian taxable units (approximately $2.6 million in 2020). Any remaining excess is levied as payment for the benefit of the regional governments. These levies fund worker training, employment promotion, entrepreneurship and various other programs. In Mexico, workers' participation is determined using the guidelines established in the Mexican income tax law at a rate of 10% of pre-tax earnings as adjusted by the tax law. The provision for workers’ participation is allocated to “Cost of sales (exclusive of depreciation, amortization and depletion)” and to “selling, general and administrative” in the consolidated statement of earnings, proportional to the number of workers in the production and administrative areas, respectively. Workers’ participation expense for the three years ended December 31, 2020 was as follows (in millions): 2020 2019 2018 Current $ 248.5 $ 188.8 $ 219.9 Deferred 19.8 29.8 9.8 $ 268.3 $ 218.6 $ 229.7

LEASES_

LEASES:	12 Months Ended
LEASES:	Dec. 31, 2020
LEASES:
LEASES:	NOTE 9—LEASES: The Company has operating leases for power generating facilities, vehicles and properties. The Company recognizes lease expense for these leases on a straight-line basis over the lease term. Some of the Company’s leases include both lease and non-lease components which are accounted for separately. The Company’s leases have remaining lease terms of two years to 13 years, and do not include options to extend the leases. The Company’s lease agreements do not contain options to purchase the leased assets or to terminate the leases before the expiration date. In addition, the Company’s lease contracts do not have any material residual value guarantees or material restrictive covenants. As none of the Company’s leases provides an implicit rate, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The weighted average remaining lease term for the Company’s leases is 9 years, and the weighted average discount rate for these leases is 3.71%. The operating lease expense recognized in the years ended December 31, 2020 and 2019 was classified as follows (in millions): Classification 2020 2019 Cost of sales (exclusive of depreciation, amortization and depletion) $ 114.4 $ 114.4 Selling, general and administrative 0.2 0.2 Exploration 0.2 0.2 Total lease expense $ 114.8 $ 114.8 The Company’s short-term lease costs for the year ended December 31, 2020 were $0.1 million. Maturities of lease liabilities are as follows: Lease liabilities Year (in millions) 2021 $ 114.7 2022 113.7 2023 112.3 2024 104.7 2025 103.7 After 2025 723.0 Total lease payments $ 1,272.1 Less: interest on lease liabilities (293.1) Present value of lease payments $ 979.0

ASSET RETIREMENT OBLIGATION_

ASSET RETIREMENT OBLIGATION:	12 Months Ended
ASSET RETIREMENT OBLIGATION:	Dec. 31, 2020
ASSET RETIREMENT OBLIGATION:
ASSET RETIREMENT OBLIGATION:	NOTE 10—ASSET RETIREMENT OBLIGATION: Peruvian operations: The Company maintains an asset retirement obligation for its mining properties in Peru, as required by the Peruvian Mine Closure Law. In accordance with the requirements of this law the Company’s closure plans were approved by the Peruvian Ministry of Energy and Mines (“MINEM”). As part of the closure plans, the Company is required to provide annual guarantees over the estimated life of the mines, based on a present value approach, and to furnish the funds for the asset retirement obligation. This law requires a review of closing plans every five years. On June 24, 2019, MINEM approved a change to the guarantees required for the mining closure plans. The new regulation specifies that the annual guarantees can be secured with real estate up to a maximum of 50% and the remaining amount with credit instruments. Currently, the Company has pledged the value of its Lima office complex for the 50% of the guarantee and with a stand-by letter of credit for the other 50% as security for this obligation. Through January 2021, the Company provided total guarantees of $56.5 million. The closure cost recognized for this liability includes the cost, as outlined in its closure plans, of dismantling the Toquepala and Cuajone concentrators, the Ilo smelter and refinery, and the shops and auxiliary facilities at the three units. In March 2016, MINEM approved the Mining Closure Plan for the Toquepala expansion project and the revised closure plans for the Cuajone mine and the Ilo facilities were approved in January and October 2019, respectively. As result of these new estimates, the Company increased the asset retirement obligation by $28.1 million in 2019. The closure plan for the Tia Maria project was approved in February 2017. The Company, however, has not recorded a retirement obligation for the project because the work on the project is on hold. The Company believes that under these circumstances the recording of a retirement obligation is not appropriate. Mexican operations: The Company has recognized an estimated asset retirement obligation for its mining properties in Mexico as part of its environmental commitment. Even though there is currently no enacted law, statute, ordinance, written or oral contract requiring the Company to carry out mine closure and environmental remediation activities, the Company believes that an obligation presently exists based on historical government requirements for the closure of any facility. The overall cost recognized for mining closure in Mexico includes the estimated costs of dismantling concentrators, smelter and refinery plants, shops and other facilities. During 2020, the Company made a change in the estimate for the asset retirement obligation for its Mexican operations, mainly due to a detailed review of the closing activities required for each facility. The effect of this change was an increase in the asset retirement obligation of $269.3 million, which was recorded in December 2020. The following table summarizes the asset retirement obligation activity for the years ended December 31, 2020 and 2019 (in millions): 2020 2019 Balance as of January 1 $ 262.3 $ 217.7 Changes in estimates 269.3 36.4 Closure payments (1.2) (5.3) Accretion expense 14.6 13.5 Balance as of December 31, $ 545.0 $ 262.3

FINANCING

FINANCING	12 Months Ended
FINANCING	Dec. 31, 2020
FINANCING:
FINANCING:	NOTE 11—FINANCING: Long-term debt (in millions): Carrying value as of Face Issuance Issuance December 31, amount discount costs 2020 3.500% Senior unsecured notes due 2022 $ 300 (0.2) $ (0.3) $ 299.5 3.875% Senior unsecured notes due 2025 500 (1.3) (1.2) 497.5 9.250% Yankee bonds due 2028 51.2 — — 51.2 7.500% Senior unsecured notes due 2035 1,000 (12.0) (8.0) 980.0 6.750% Senior unsecured notes due 2040 1,100 (6.9) (5.6) 1,087.5 5.250% Senior unsecured notes due 2042 1,200 (18.6) (6.2) 1,175.2 5.875% Senior unsecured notes due 2045 1,500 (16.1) (8.5) 1,475.4 4.500% Minera Mexico Senior unsecured notes due 2050 1,000 (12.5) (9.6) 977.9 Total $ 6,651.2 $ (67.6) $ (39.4) 6,544.2 Less, current portion — Total long-term debt $ 6,544.2 Carrying value as of Face Issuance Issuance December 31, amount discount costs 2019 5.375% Senior unsecured notes due 2020 $ 400 (0.1) $ (0.1) $ 399.8 3.500% Senior unsecured notes due 2022 300 (0.3) (0.5) 299.2 3.875% Senior unsecured notes due 2025 500 (1.6) (1.5) 496.9 9.250% Yankee bonds due 2028 51 — — 51.2 7.500% Senior unsecured notes due 2035 1,000 (12.4) (8.3) 979.3 6.750% Senior unsecured notes due 2040 1,100 (7.1) (5.7) 1,087.2 5.250% Senior unsecured notes due 2042 1,200 (19.0) (6.3) 1,174.7 5.875% Senior unsecured notes due 2045 1,500 (16.4) (8.6) 1,475.0 4.500% Minera Mexico Senior unsecured notes due 2050 1,000 (12.7) (9.8) 977.5 Total $ 7,051 $ (69.6) $ (40.8) 6,940.8 Less, current portion (399.8) Total long-term debt $ 6,541.0 The bonds, referred above as “Yankee bonds”, contain a covenant requiring Minera Mexico to maintain a ratio of EBITDA to interest expense of not less than 2.5 to 1.0 as such terms are defined in the debt instrument. At December 31, 2020, Minera Mexico was in compliance with this covenant. Between July 2005 and November 2012 the Company issued senior unsecured notes six times totaling $4.2 billion, as listed above. Interest on the notes is paid semi-annually in arrears. The notes rank pari passu pari passu The indentures relating to the notes contain certain restrictive covenants, including limitations on liens, limitations on sale and leaseback transactions, rights of the holders of the notes upon the occurrence of a change of control triggering event, limitations on subsidiary indebtedness and limitations on consolidations, mergers, sales or conveyances. Certain of these covenants cease to be applicable before the notes mature if the Company obtains an investment grade rating. The Company obtained investment grade rating in 2005. The Company has registered these notes under the Securities Act of 1933, as amended. The Company may issue additional debt from time to time pursuant to certain of the indentures. If the Company experiences a “Change of Control Triggering Event”, the Company must offer to repurchase the notes at a purchase price equal to 101% of the principal amount thereof, plus accrued and unpaid interest, if any. A Change of Control Trigger Event means a Change of Control (as defined) and a rating decline (as defined), that is, if the rating of the notes, by at least one of the rating agencies shall be decreased by one or more gradations. At December 31, 2020, the Company was in compliance with the covenants of the notes. On September 26, 2019, SCC’s subsidiary Minera Mexico S.A. de C.V. issued $1.0 billion of fixed-rate senior notes with a discount of $12.7 million. Additionally, issuance costs of $9.8 million associated with these notes were paid and deferred. The unamortized balance of the discount and the costs are presented net of the carrying value of the debt issued and are amortized as interest expense over the life of the loan. This debt was issued in one tranche, due in 2050 at an annual interest rate of 4.5%. Interest on the notes is paid semi-annually in arrears. The Company intends to use the net proceeds from this offering (i) to finance Minera Mexico expansion program, including the Buenavista Zinc, Pilares and El Pilar projects, (ii) for other capital expenditures and (iii) for general corporate purposes. The notes constitute general unsecured obligations of Minera Mexico. The notes were issued in an unregistered offering pursuant to Rule 144A and Regulation S under the Securities Act of 1933. The Company capitalized the costs associated with the issuance of this facility, which are included as part of the amortized cost of the long-term debt in the consolidated balance sheet. In connection with the transaction, on September 26, 2019, Minera Mexico entered into an indenture with Wells Fargo Bank, National Association, as trustee, which provided for the issuance, and set forth the terms of the notes described above. The indenture contains covenants that limit Minera Mexico's ability to, among other things, incur certain liens securing indebtedness, engage in certain sale and leaseback transactions, and enter into certain consolidations, mergers, conveyances, transfers or leases of all or substantially all of Minera Mexico's assets. Aggregate maturities of the outstanding borrowings at December 31, 2020, are as follows: Principal Years Due() (in millions) 2021 $ — 2022 300.0 2023 — 2024 — 2025 500.0 Thereafter 5,851.2 Total $ 6,651.2 ()

BENEFIT PLANS

BENEFIT PLANS	12 Months Ended
BENEFIT PLANS	Dec. 31, 2020
BENEFIT PLANS:
BENEFIT PLANS:	NOTE 12—BENEFIT PLANS: Post retirement defined benefit plans and defined contribution plan The Company has two noncontributory defined benefit pension plans covering former salaried employees in the United States and certain former expatriate employees in Peru (the “Expatriate Plan”). Effective October 31, 2000, the Board of Directors amended the qualified pension plan to suspend the accrual of benefits. In addition, the Company’s Mexican subsidiaries have a defined contribution pension plan for salaried employees and a non-contributory defined benefit pension plan for union employees (the “Mexican Plan”). The components of net periodic benefit costs calculated in accordance with ASC 715 “Compensation retirement benefits,” using December 31 as a measurement date, consist of the following: (in millions) 2020 2019 2018 Service cost $ 1.4 $ 1.1 $ 1.0 Interest cost 1.7 1.8 1.6 Expected return on plan assets (2.9) (3.5) (3.4) Amortization of net actuarial loss 0.1 — — Amortization of prior service cost / (credit) 0.2 0.2 0.2 Settlement / Curtailment (0.4) — (0.2) Amortization of net loss/(gain) 0.2 0.3 0.2 Net periodic benefit cost $ 0.3 $ (0.1) $ (0.6) The change in benefit obligation and plan assets and a reconciliation of funded status are as follows: As of December 31, (in millions) 2020 2019 Change in benefit obligation: Projected benefit obligation at beginning of year $ 33.7 $ 27.4 Service cost 1.4 1.1 Interest cost 1.7 1.8 Settlement — — Benefits paid (1.9) (1.8) Actuarial (gain)/loss (4.2) 3.6 Actuarial gain assumption changes 0.8 0.9 Inflation adjustment (1.6) 0.7 Projected benefit obligation at end of year $ 29.9 $ 33.7 Change in plan assets: Fair value of plan assets at beginning of year $ 51.6 $ 46.7 Actual return on plan assets 6.5 4.8 Employer contributions (0.6) (0.6) Benefits paid (0.9) (0.9) Currency exchange rate adjustment (2.2) 1.6 Fair value of plan assets at end of year $ 54.4 $ 51.6 Funded status at end of year: $ 24.5 $ 17.9 ASC-715 amounts recognized in statement of financial position consists of: Non-current assets $ 24.5 $ 17.9 Total $ 24.5 $ 17.9 ASC-715 amounts recognized in accumulated other comprehensive income (net of income taxes of $(2.3) million and $(5.4) million in 2020 and 2019, respectively) consists of: Net loss (gain) $ 3.0 $ 7.6 Prior service cost 1.2 1.4 Total $ 4.2 $ 9.0 The following table summarizes the changes in accumulated other comprehensive income for the years ended December 31, related to the defined benefit pension plan, net of income tax: (in millions) 2020 2019 Reconciliation of accumulated other comprehensive income: Accumulated other comprehensive income at beginning of plan year $ 9.0 $ 7.2 Net loss/(gain) amortized during the year (4.1) 1.9 Net loss/(gain) occurring during the year (0.3) (0.2) Prior service cost (credit) — — Currency exchange rate adjustment (0.4) 0.1 Net adjustment to accumulated other comprehensive income (net of income taxes of $3.1 million and $(2.2) million in 2020 and 2019, respectively) (4.8) 1.8 Accumulated other comprehensive income at end of plan year $ 4.2 $ 9.0 The following table summarizes the amounts in accumulated other comprehensive income amortized and recognized as a component of net periodic benefit cost in 2020 and 2019, net of income tax: (in millions) 2020 2019 Net loss / (gain) $ (4.1) $ 1.8 Amortization of net (loss) gain (0.3) (0.2) Amortization of prior services cost (credit) — — Total amortization expenses $ (4.4) $ 1.6 The assumptions used to determine the pension obligations are: Expatriate Plan 2020 2019 2018 Discount rate 1.90 % 2.85 % 3.90 % Expected long-term rate of return on plan asset 3.50 % 4.00 % 4.00 % Rate of increase in future compensation level N/A N/A N/A Mexican Plan() 2020 2019 2018 Discount rate 7.43 % 7.15 % 8.45 % Expected long-term rate of return on plan asset 7.43 % 7.15 % 8.45 % Rate of increase in future compensation level 4.50 % 4.50 % 4.50 % () The scheduled maturities of the benefits expected to be paid in each of the next five years, and thereafter, are as follows: Expected Years Benefit Payments (in millions) 2021 $ 3.1 2022 1.7 2023 1.8 2024 2.0 2025 1.8 2026 to 2028 12.5 Total $ 22.9 Expatriate Plan The Company’s funding policy is to contribute amounts to the qualified plan sufficient to meet the minimum funding requirements set forth in the Employee Retirement Income Security Act of 1974 plus such additional amounts as the Company may determine to be appropriate. Plan assets are invested in a group annuity contract with Metropolitan Life Insurance Company (“MetLife”). The Contract invests in the MetLife General Account Payment Fund (the "General Account") and the MetLife Broad Market Core Bond Fund (the “Bond Fund”) managed by BlackRock, Inc. The General Account is broadly diversified across asset classes and backed by the total capital of MetLife. The Bond Fund seeks to outperform the Bloomberg Barclays ® U.S. Aggregate Bond Index, net of fees, over a full market cycle. The Bond Fund invests in publicly traded, investment grade securities. These may include corporate securities, mortgage securities, treasuries and cash, agency securities, commercial mortgage backed securities and other investment vehicles adhering to the fund’s investment objectives. These investments are classified as Level 1 because they are valued using quoted prices of the same securities as they consist of instruments which are publicly traded. Plan assets are invested with the objective of maximizing returns with an acceptable level of risk and maintaining adequate liquidity to fund expected benefit payments. The Company's policy for determining asset mix-targets to meet investment objectives includes periodic consultation with recognized third-party investment consultants. The expected long-term rate of return on plan assets is reviewed annually, taking into consideration asset allocations, historical returns and the current economic environment. Based on these factors the Company expects its assets will earn an average of 4.00% per annum assuming its long-term mix will be consistent with its current mix. Mexican Plan Minera Mexico’s policy for determining asset mix targets includes periodic consultation with recognized third-party investment consultants. The expected long-term rate of return on plan assets is updated periodically, taking into consideration assets allocations, historical returns and the current economic environment. The fair value of plan assets is impacted by general market conditions. If actual returns on plan assets vary from the expected returns, actual results could differ. The plan assets are managed by three financial institutions, Scotiabank Inverlat S.A., Banco Santander and GBM Grupo Bursatil Mexicano, S.A. 78% of the funds are invested in Mexican government securities, including treasury certificates and development bonds of the Mexican government. The remaining 22% is invested in common shares of Grupo Mexico. The plan assets are invested without restriction in active markets that are accessible when required and are therefore considered as level 1, in accordance with ASC 820 “Fair Value Measurement.” These plans accounted for approximately 100% of benefit obligations. The following table represents the asset mix of the investment portfolio as of December 31: 2020 2019 Asset category: Treasury bills 78 % 80 % Equity securities 22 % 20 % 100 % 100 % The amount of contributions that the Company expects to pay to the plan during 2021 is $2.3 million. Post-retirement Health Care Plan: United States: The Company adopted a post-retirement health care plan for retired salaried employees eligible for Medicare in 1996. The Company manages the plan and is currently providing health benefits to retirees. The plan is accounted for in accordance with ASC 715 “Compensation retirement benefits.” In Mexico, health services are provided by the Mexican Social Security Institute. The components of net period benefit costs for the three years ended December 31, 2020 are as follows: (in millions) 2020 2019 2018 Interest cost $ 1.3 $ 0.9 $ 0.9 Amortization of prior service cost/ (credit) — (0.2) (0.2) Net periodic benefit cost $ 1.3 $ 0.7 $ 0.7 The change in benefit obligation and a reconciliation of funded status are as follows: As of December 31, (in millions) 2020 2019 Change in benefit obligation: Projected benefit obligation at beginning of year $ 20.6 $ 11.9 Interest cost 1.3 0.9 Actuarial loss/ (gain)-claims cost — — Benefits paid (1.5) (1.3) Actuarial (gain)/loss 4.5 8.6 Inflation adjustment (1.1) 0.5 Projected benefit obligation at end of year $ 23.8 $ 20.6 Change in plan assets: Fair value of plan assets at beginning of year $ — $ — Employer contributions 0.1 0.1 Benefits paid (0.1) (0.1) Fair value of plan assets at end of year $ — $ — Funded status at end of year: $ 23.8 $ 20.6 ASC-715 amounts recognized in statement of financial position consists of: Current liabilities $ — $ (0.1) Non-current liabilities (23.8) (20.5) Total $ (23.8) $ (20.6) ASC-715 amounts recognized in accumulated other comprehensive income consists of: Net loss (gain) $ 4.6 $ 1.5 Total (net of income taxes of $(1.9) million and $(0.7) million in 2020 and 2019, respectively) $ 4.6 $ 1.5 The following table summarizes the changes in accumulated other comprehensive income for the years ended December 31, related to the post-retirement health care plan, net of income tax: As of December 31, (in millions) 2020 2019 Reconciliation of accumulated other comprehensive income: Accumulated other comprehensive income at beginning of plan year $ 1.5 $ (4.4) Net loss/(gain) occurring during the year 3.2 6.0 Net loss/(gain) amortized during the year — 0.1 Currency exchange rate adjustment (0.1) (0.2) Net adjustment to accumulated other comprehensive income (net of income taxes of $(1.2) million and $(2.6) million in 2020 and 2019, respectively) 3.1 5.9 Accumulated other comprehensive income at end of plan year $ 4.6 $ 1.5 The following table summarizes the amounts in accumulated other comprehensive income amortized and recognized as a component of net periodic benefit cost in 2020 and 2019, net of income tax: As of December 31, (in millions) 2020 2019 Net loss / (gain) $ 3.2 $ 5.9 Amortization of net (loss) gain — 0.2 Total amortization expenses $ 3.2 $ 6.1 The discount rates used in the calculation of other post-retirement benefits and cost as of December 31 were: 2020 2019 2018 Expatriate health plan Discount rate 1.90 % 2.85 % 3.90 % Mexican health plan Weighted average discount rate 7.43 % 7.15 % 8.45 % The benefits expected to be paid in each of the next five years, and thereafter, are as follows: Expected Year Benefit Payments (in millions) 2021 $ 1.5 2022 1.6 2023 1.5 2024 1.5 2025 1.6 2026 to 2030 8.6 Total $ 16.3 Expatriate Health Plan For measurement purposes for pre 65 year old participants, a 5.1% annual rate of increase in the per capita cost of covered health care benefits was assumed for 2020 which gradually decrease to 4.2%. For post 65 year old the annual rate of increase in the per capita cost for 2020 is 4.9% which is assumed to decrease gradually to 4.0%. Assumed health care cost trend rates can have a significant effect on amounts reported for health care plans. However, because of the size of the Company’s plan, a one percentage-point change in assumed health care trend rate would not have a significant effect. Mexican Health Plan For measurement purposes, a 4.5% annual rate of increase in the per capita cost of covered health care benefits was assumed for 2020 and remains at that level thereafter. An increase in other benefit cost trend rates have a significant effect on the amount of the reported obligations, as well as component cost of the other benefit plan. One percentage-point change in assumed other benefits cost trend rates would have the following effects: One Percentage Point (in millions) Increase Decrease Effect on total service and interest cost components $ 1.9 $ 1.5 Effect on the post-retirement benefit obligation $ 24.7 $ 22.2

COMMITMENTS AND CONTINGENCIES_

COMMITMENTS AND CONTINGENCIES:	12 Months Ended
COMMITMENTS AND CONTINGENCIES:	Dec. 31, 2020
COMMITMENTS AND CONTINGENCIES:
COMMITMENTS AND CONTINGENCIES:	NOTE 13—COMMITMENTS AND CONTINGENCIES: Environmental matters: The Company has instituted extensive environmental conservation programs at its mining facilities in Peru and Mexico. The Company’s environmental programs include, among others, water recovery systems to conserve water and minimize the impact on nearby streams, reforestation programs to stabilize the surface of the tailings dams and the implementation of scrubbing technology in the mines to reduce dust emissions. Environmental capital investments in years 2020, 2019 and 2018, were as follows (in millions): 2020 2019 2018 Peruvian operations () $ (3.3) $ 18.6 $ 59.3 Mexican operations 41.1 64.3 43.5 $ 37.8 $ 82.9 $ 102.8 () Peruvian operations Air Quality Standards (“AQS”): Soil Environmental Quality Standards (“SQS”): for environmentally impacted sites in each of its operation units (Toquepala, Cuajone and Ilo) with the assistance of consulting companies. The cost of these SDPs are not material, either individually or in aggregated form, for the financial statements of the Company. Mexican operations The principal legislation applicable to the Company’s Mexican operations is the Federal General Law of Ecological Balance and Environmental Protection (the “General Law”), which is enforced by the Federal Bureau of Environmental Protection (“PROFEPA”). PROFEPA monitors compliance with environmental legislation and enforces Mexican environmental laws, regulations and official standards. It may also initiate administrative proceedings against companies that violate environmental laws, which in the most extreme cases may result in the temporary or permanent shutdown of non-complying facilities, the revocation of operating licenses and/or other sanctions or fines. In 2011, the General Law was amended to provide an individual or entity the ability to contest administrative acts, including environmental authorizations, permits or concessions granted, without the need to demonstrate the actual existence of harm to the environment as long as it can be argued that the harm may be caused. In addition, in 2011, amendments to the Civil Federal Procedures Code (“CFPC”) were enacted, which established three categories of collective actions under which a group of 30 or more individuals can be considered sufficient to prove a “legitimate interest” to file civil actions for injuries derived from alleged violations of environmental, consumer protection, financial services and economic competition laws and to seek restitution or economic compensation for the alleged injuries or the suspension of the activities which allegedly generated the injuries in question. The amendments to the CFPC may result in more litigation, with plaintiffs seeking remedies, including suspension of the activities alleged to cause harm. In 2013, the Environmental Liability Federal Law was enacted. The law establishes general guidelines for actions to be considered to likely cause environmental harm. If a possible determination regarding harm occurs, environmental clean-up and remedial actions sufficient to restore environment to a pre-existing condition should be taken. Under this law, if restoration is not possible, compensation measures should be provided. Criminal penalties and monetary fines can be imposed under this law. On February 2019, the Mexican Supreme Court confirmed the constitutionality of an ecological tax on extractive activities developed in the state of Zacatecas, which taxes the environmental remediation actions; emissions of certain gases to the atmosphere; emissions of pollutant substances to the soil or water; and waste storage within the state territory. The Company has determined that this new environmental regulation will have no impact on its financial position. Guaymas sulfuric acid spill On July 9, 2019, there was an incident at the Company´s Marine Terminal in Guaymas, Sonora, that caused the discharge of approximately three cubic meters of sulfuric acid into the sea in the industrial port area. The Guaymas bay has an estimated water volume of 340 million cubic meters. The spill, upon entering in contact with the sea’s alkaline conditions, led to quick dilution of the discharge and the sulfuric acid was naturally and immediately neutralized. As a result, the discharge was considered harmless; the report from the Ministry of Navy found that neither the flora nor fauna of the port area were affected. On July 10, 2019, PROFEPA made a first inspection of the area, concluding that the Company executed all the appropriate procedures in order to contain the discharge, and no reference was made to the existence of negative impacts on the environment resulting from the incident. On Friday, July 19, 2019, PROFEPA revisited the facilities to carry out a second inspection, declaring a partial temporary shutdown that affected only the storage process and transportation of sulfuric acid at the terminal, arguing the absence of an authorization of environmental impact. It is important to note that these facilities have been in operation since 1979, prior to the 1988 Mexican General Law of Ecological Balance and the Protection of the Environment. Companies that were operating before the aforementioned law are exempt from the permit requirement. In addition, in 2009, PROFEPA awarded a certification of “Clean Industry and Environmental Quality” to the facility which was subsequently renewed four times (for a two-year period each time). The Company is not aware of the reasons or causes for this partial and temporary closure, but will continue working with the environmental authorities to provide certainty that the operation is in strict compliance with environmental regulations. The Company expects the environmental authorities to suspend the partial temporary shutdown, once they resolve their concerns. Currently, the Company does not expect any impact on its operations. As of December 31, 2020, the matter is pending resolution. Litigation matters Peruvian operations The Tia Maria Mining Project There are five lawsuits filed against the Peruvian Branch of the Company related to the Tia Maria project. The lawsuits seek (i) to declare null and void the resolution that approved the Environmental Impact Assessment of the project; (ii) the cancellation of the project and the withdrawal of mining activities in the area; (iii) to declare null and void the mining concession application for the Tia Maria project; and (iv) to declare null and void the resolution that approved the construction license. The lawsuits were filed by Messrs. Jorge Isaac del Carpio Lazo (filed May 22, 2015), Ernesto Mendoza Padilla (filed May 26, 2015), Juan Alberto Guillen Lopez (filed June 18, 2015), Junta de Usuarios del Valle del Tambo (filed April 30, 2015), and Gobierno Regional de Arequipa (filed December 16, 2019). The del Carpio Lazio case was rejected by the court of first instance on November 14, 2016. The plaintiff filed an appeal before the Superior Court on January 3, 2017. On January 9, 2018, the lawyers of both parties presented their respective positions before the Appellate Court. On March 8, 2018, the Appellate Court issued its final decision, which upheld the first instance ruling. On April 27, 2018, the plaintiff filed an extraordinary appeal before the Supreme Court. As of December 31, 2020, the case remains pending resolution. The Mendoza Padilla case was initially rejected by the lower court on July 8, 2015. This ruling was confirmed by the Superior Court on June 14, 2016. On July 12, 2016, the case was appealed before the Constitutional Court. On November 20, 2018, the Constitutional Court reversed the previous decisions and remanded the case to the lower court for further action. In the third quarter of 2020, the Company was notified that the complaint had been reinstated. The Company answered the complaint on September 15, 2020. On December 2, 2020, the lower court issued a resolution, considering the complaint answered. As of December 31, 2020, the case remains pending resolution. The Guillen Lopez case is currently before the lower court. On July 19, 2019, the oral arguments took place. On January 7, 2020, the Judge decided to suspend the proceeding until the del Carpio Lazio case is concluded. Therefore, as of December 31, 2020, the case remains pending resolution. The Junta de Usuarios del Valle del Tambo case is currently before the lower court. On May 2016, the Company was included in the process, after the Ministry of Energy and Mines filed a civil complaint. On March 6, 2019, the Company was formally notified of the lawsuit and answered the complaint on March 20, 2019. On July 8, 2019, the Company requested the suspension of the proceeding until the del Carpio Lazio case is concluded. As of December 31, 2020, the case remains pending resolution. The Gobierno Regional de Arequipa case is currently before the lower court and the Company answered the complaint on September 15, 2020. As of December 31, 2020, the case remains pending resolution. The Company asserts that these lawsuits are without merit and is vigorously defending against them. The potential contingency amount for these cases cannot be reasonably estimated by management at this time. Special Regional Pasto Grande Project (“Pasto Grande Project”) In 2012, the Pasto Grande Project, an entity of the Regional Government of Moquegua, filed a lawsuit against SCC’s Peruvian Branch alleging property rights over a certain area used by the Peruvian Branch and seeking the demolition of the tailings dam where SCC’s Peruvian Branch has deposited its tailings from the Toquepala and Cuajone operations since 1995. The Peruvian Branch has had title to use the area in question since 1960 and has, since 1995, constructed and operated the tailings dams with proper governmental authorization. Upon a motion filed by the Peruvian Branch, the lower court has included MINEM as a defendant in this lawsuit. MINEM has answered the complaint and denied the validity of the claim. As of December 31, 2020, the case was pending resolution without further developments. SCC’s Peruvian Branch asserts that the lawsuit is without merit and is vigorously defending against it. The amount of this contingency cannot be reasonably estimated by management at this time. Mexican operations The Accidental Spill at Buenavista Mine of 2014 In relation to the 2014 accidental spill of copper sulfate solution that occurred at a leaching pond in the Buenavista mine, the following legal procedures are pending against the Company: On August 19, 2014, PROFEPA, as part of the administrative proceeding initiated after the spill, announced the filing of a criminal complaint against Buenavista del Cobre S.A. de C.V. (“BVC”), a subsidiary of the Company, in order to determine those responsible for environmental damages. During the second quarter of 2018, the criminal complaint was dismissed. This decision was appealed and was pending resolution as of December 31, 2020. Through the first half of 2015, six collective action lawsuits were filed in federal courts in Mexico City and Sonora against two subsidiaries of the Company seeking economic compensation, clean up and remedial activities in order to restore the environment to its pre-existing conditions. Two of the collective action lawsuits have been dismissed by the court. As of December 31, 2020, four lawsuits continue in process: three were filed by Acciones Colectivas de Sinaloa, A.C. and one, by Defensa Colectiva, A.C.; requesting precautionary measures about construction of facilities for monitoring public health services and prohibiting the closure of the Rio Sonora Trust. Similarly, during 2015, eight civil action lawsuits were filed against BVC in the state courts of Sonora seeking damages for alleged injuries and for moral damages as a consequence of the spill. The plaintiffs in the state court lawsuits are: Jose Vicente Arriola Nunez et al; Santana Ruiz Molina et al; Andres Nogales Romero et al; Teodoro Javier Robles et al; Gildardo Vasquez Carvajal et al; Rafael Noriega Souffle et al; Grupo Banamichi Unido de Sonora El Dorado, S.C. de R.L. de C.V; and Marcelino Mercado Cruz. In 2016, three additional civil action lawsuits, claiming similar damages, were filed by Juan Melquicedec Lebaron; Blanca Lidia Valenzuela Rivera et al and Ramona Franco Quijada et al. In 2017, BVC was served with thirty-three additional civil action lawsuits, claiming similar damages. The lawsuits were filed by Francisco Javier Molina Peralta et al; Anacleto Cohen Machini et al; Francisco Rafael Alvarez Ruiz et al; Jose Alberto Martinez Bracamonte et al; Gloria del Carmen Ramirez Duarte et al; Flor Margarita Sabori et al; Blanca Esthela Ruiz Toledo et al; Julio Alfonso Corral Dominguez et al; Maria Eduwiges Bracamonte Villa et al; Francisca Marquez Dominguez et al; Jose Juan Romo Bravo et al; Jose Alfredo Garcia Leyva et al; Gloria Irma Dominguez Perez et al; Maria del Refugio Romero et al; Miguel Rivas Medina et al; Yolanda Valenzuela Garrobo et al; Maria Elena Garcia Leyva et al; Manuel Alfonso Ortiz Valenzuela et al; Francisco Alberto Arvayo Romero et al; Maria del Carmen Villanueva Lopez et al; Manuel Martin Garcia Salazar; Miguel Garcia Arguelles et al; Dora Elena Rodriguez Ochoa et al; Honora Eduwiges Ortiz Rodriguez et al; Francisco Jose Martinez Lopez et al; Maria Eduwiges Lopez Bustamante; Rodolfo Barron Villa et al, Jose Carlos Martinez Fernandez et al, Maria de los Angeles Fabela et al; Rafaela Edith Haro et al; Luz Mercedes Cruz et al; Juan Pedro Montaño et al; and Juana Irma Alday Villa. In the first quarter of 2018, BVC was served with another civil action lawsuit, claiming similar damages. The lawsuit was filed by Alma Angelina Del Cid Rivera et al. In the last quarter of 2018, BVC was served with other three civil action lawsuits, claiming similar damages. These lawsuits were filed by Los Corrales de la Estancia, S.C. de R.L.; Jose Antonio Navarro; Jesus Maria Peña Molina, et al; these actions were dismissed by the court, because they have expired. As of December 31, 2020, forty-five cases remain pending resolution. In 2015, four constitutional lawsuits (juicios de amparo) were filed before Federal Courts against various authorities and against a subsidiary of the Company, arguing; (i) the alleged lack of a waste management program approved by SEMARNAT; (ii) the alleged lack of a remediation plan approved by SEMARNAT with regard to the August 2014 spill; (iii) the alleged lack of community approval regarding the environmental impact authorizations granted by SEMARNAT to one subsidiary of the Company; and (iv) the alleged inactivity of the authorities with regard of the spill in August 2014. The plaintiffs of these lawsuits are: Francisca Garcia Enriquez, et al filed two lawsuits, Francisco Ramon Miranda, et al and Jesus David Lopez Peralta et al. In the third quarter of 2016, four additional constitutional lawsuits, claiming similar damages were filed by Mario Alberto Salcido et al; Maria Elena Heredia Bustamante et al; Martin Eligio Ortiz Gamez et al; and Maria de los Angeles Enriquez Bacame et al. In the third quarter of 2017, BVC was served with another constitutional lawsuit filed by Francisca García Enriquez et al. In 2018, BVC was served with two additional constitutional lawsuits that were filed against SEMARNAT by Norberto Bustamante et al. Regarding the constitutional lawsuit filed by Maria Elena Heredia Bustamante et al; in which it was claimed the lack of community approval regarding the authorization granted by SEMARNAT to build the new BVC tailings dam, on September 5, 2018, the Supreme Court of Justice issued a resolution establishing that such authorization was granted to BVC in compliance with the applicable legislation. However, SEMARNAT must carry out a public meeting to inform the community of the technical aspects required to build the dam, potential impacts and prevention measures, with no material effects to BVC’s operations. SEMARNAT has carried out the consultation ordered by the Supreme Court. As a result, has informed the corresponding Judge about its compliance with the resolution, in which BVC was imposed additional measures of environmental impact prevention, such as: (i) the building of at least three monitoring wells downstream from the curtain of the contingency dam in a period of six months; (ii) monitoring of the groundwater level and water quality every six months; (iii) carrying out rain collection work in order to restore water to the Sonora River basin, for which six months are granted to present the execution program; (iv) determine the location of wildlife conservation and protection areas and define the need to establish biological corridors; (v) obtain photographic or videographic evidence every six months; (vi) submitting to SEMARNAT two years before the closure and abandonment of the site, or earlier if necessary, the closure program that includes the cleaning and restoration of the soil including Mexican regulation NOM-141; (vii) include the measures in the Environmental Monitoring Program according to the environmental components impacted; and (viii) hiring an external environmental consultant to validate compliance with the current and new conditions that are imposed. The foregoing does not impact BVC’s operations. Likewise, it is noted that the lawsuits filed by Maria de los Angeles Enriquez Bacame and Norberto Bustamante have been dismissed and closed without prejudice to the Company. As of December 31, 2020, the remaining cases were still pending resolution. It is currently not possible to determine the extent of the damages sought in these state and federal lawsuits but the Company believes that these lawsuits are without merit. Accordingly, the Company is vigorously defending against them. Nevertheless, the Company believes that none of the legal proceedings resulting from the spill, individually or in the aggregate, would have a material effect on its financial position or results of operations. Corporate operations Carla Lacey, on behalf of herself and all other similarly situated stockholders of Southern Copper Corporation, and derivatively on behalf of Southern Copper Corporation In April 2019, a derivative lawsuit was filed against the Company, certain current and former Directors, and Grupo Mexico in the Delaware Court of Chancery relating to certain construction contracts, contracts for the purchase and sale of minerals, and transportation contracts entered into between the Company’s subsidiaries and subsidiaries of Grupo Mexico. In October 2019, the plaintiff amended the complaint to include claims related to certain administrative services contracts between the Company’s subsidiaries and Grupo Mexico. The amended complaint alleges, among other things, that the construction contracts, the mineral contracts, the transportation contracts, and the administrative services contracts were unfair as a result of breaches of fiduciary duties and the Company’s charter. The amended complaint also added Americas Mining Corporation (“AMC”) as a defendant, alleging that AMC breached its fiduciary duties as a controlling stockholder of the Company. The amended complaint seeks, among other things, unspecified monetary damages. In January 2020, the Company, the current and former Directors, and Grupo Mexico responded to the complaint by filing motions to dismiss. The Plaintiff filed a brief in response to the motions on March 13, 2020. On July 16, 2020, the Court denied the motions to dismiss the breach of fiduciary duty claims against the Directors. On October 6, 2020, the Court dismissed the Plaintiff’s claims against Grupo Mexico for lack of personal jurisdiction. On February 11, 2021, the Court granted the Directors’ motion to dismiss plaintiff’s breach of contract claim. The Court also granted AMC’s motion to dismiss all claims against AMC other than those related to the mineral contracts. As of February 2021, because the Company has not reached a conclusion as to whether an unfavorable outcome is either probable or remote, the Company expresses no opinion as to the likelihood of an unfavorable outcome or the amount or range of any possible loss to the Company. Labor matters Peruvian operations: In May 2019, an arbitration resolved pending issues with the remaining union. The arbitral award included a salary increase of 5.5% beginning in September 2018 and a bonus of S/16,000 (approximately $4,800) for the one-year agreement, which was recorded as labor expense in the second quarter of 2019. In November 2019, the Company signed a collective bargaining agreement for three years with the same union. This agreement included, among other things, a salary increase of 5% for each year starting in September 2019 and a bonus of S/45,000 (approximately $13,300), which was recorded as labor expenses in the fourth quarter of 2019. Mexican operations: The workers of the San Martin mine were on strike since July 2007. On February 28, 2018, the striking workers of the San Martín mine of IMMSA held an election to vote on the union that would hold the collective bargaining agreement at the San Martín mine. The Federacion Nacional de Sindicatos Independientes (the National Federation of Independent Unions) won the vote by a majority. Nevertheless, the vote was challenged by the National Mining Union. On June 26, 2018, the Federal Mediation and Arbitration Board issued a ruling recognizing the election results. Due to the agreement between workers and the Company to end the protracted strike, on August 22, 2018, the Federal Mediation and Arbitration Board authorized the restart of operations of the San Martín mine. Such authorization was challenged by the National Mining Union. On April 4, 2019, the Federal Mediation and Arbitration Board recognized, once again, the election results from February 28, 2018, by which the National Federation of Independent Unions won by a majority. In the last quarter of 2019, a Federal Court issued a resolution that established that the Labor Court should analyze the list of workers with the right to vote in the union election. The Company and the National Federation of Independent Unions challenged such determination before the Supreme Court of Justice and the case was still pending resolution as of December 31, 2020. The Company is working on a rehabilitation plan to restore operations at the San Martin mine with a budget of In the case of the Taxco mine, its workers have been on strike since July 2007. After several legal procedures, in August 2015, the Supreme Court decided to assert jurisdiction over the case and to rule on it directly. As of December 31, 2020, the case remains pending resolution without further developments. It is expected that operations at the Taxco mine will remain suspended until the labor issues are resolved. In view of the lengthy strike, the Company has reviewed the carrying value of the Taxco mine to ascertain whether impairment exists. The Company concluded that there is a non-material impairment of the assets located at this mine. In 2020, a small group of workers at the Charcas mine claimed an additional workers’ participation payment and a minor incident was reported. This claim lacked a legal basis because the Company had completely fulfilled said obligation with the workers in question. Consequently, the Company took legal action and through conciliation and mediation with labor authorities, the incident concluded with no further repercussions for the Company. Other legal matters The Company is involved in various other legal proceedings incidental to its operations, but the Company does not believe that decisions adverse to it in any such proceedings, individually or in the aggregate, would have a material effect on its financial position or results of operations. Other commitments: Peruvian Operations Tia Maria: On August 1, 2014, the Company received the final approval of Tia Maria’s Environmental Impact Assessment (“EIA”). On July 8, 2019, the Company received the construction permit for this 120,000 ton annual SX-EW copper greenfield project with a total capital budget of On July 15, 2019, anti-mining groups staged a violent demonstration affecting economic as well as other activities in the Islay province. These actions were followed by the filing of three complaints, sponsored by groups opposing the Tia Maria project, with the Mining Council, which is the Peruvian administrative authority responsible for ruling on these complaints. The Mining Council temporarily suspended the construction permit on August 8, 2019. On October 7, 2019, as part of the process, the Mining Council conducted a hearing to hear the complaints and the Company’s position. On October 30, 2019, the Mining Council of the Peruvian Ministry of Energy and Mines ratified the construction permit for the Tia Maria project. The Company has been working to promote the welfare of the Islay province population. As part of these efforts, the Company has implemented social programs in education, healthcare and productive development to improve the quality-of-life in the region. The Company also has promoted agricultural and livestock activities in the Tambo Valley and supported growth in manufacturing, fishing and tourism in Islay. During the construction and operation phase, the Company will make it a priority to hire local labor to fill the 9,000 jobs (3,600 direct and 5,400 indirect) that the Company expects to generate during Tia Maria’s construction phase. When operating, the Company expects Tia Maria to directly employ 600 workers and indirectly provide jobs for another 4,200. Additionally, from day one of its operations, the Company will generate significant contributions to revenues in the Arequipa region via royalties and taxes. Tia Maria’s project budget is approximately $1.4 billion, of which $338.8 million has been invested through December 31, 2020. This project will use state-of-the-art SX-EW technology with the highest international environmental standards. SX-EW facilities are the most environmentally friendly in the industry as they do not require a smelting process and therefore, release no emissions into the atmosphere. Michiquillay: In June 2018, the Company signed a contract for the acquisition of the Michiquillay copper project in Cajamarca, Peru, at a purchase price of $400 million. Michiquillay is a world class mining project with estimated mineralized material of 1,150 million tons and a copper grade of 0.63%. It is expected to produce 225,000 tons of copper per year (along with by-products of molybdenum, gold and silver) for an initial mine life of more than 25 years. The Company paid $12.5 million at the signing of the contract. The balance of $387.5 million will be paid if the Company decides to develop the project and it is not a present obligation. Corporate Social Responsibility: The Company has a corporate social responsibility policy to maintain and promote the continuity of its mining operations and obtain the best results. The main objective of this policy is to integrate the Company´s operations with local communities in the areas of influence of its operations by creating permanent positive relationships to develop optimum social conditions and promote sustainable development in the area. Accordingly, the Company has made the following commitments: Tacna Region As the Toquepala expansion project has been completed, the Company considers that these commitments constitute present obligations of the Company and consequently has recorded a liability of $41.3 million in its consolidated financial statements as of December 31, 2020. In addition, the Company has committed S/ 69.7 million (approximately $19.2 million) for the construction of one infrastructure project in the Tacna region under the “social investment for taxes” (obras por impuestos) program which allows the Company to use these amounts as an advance payment of taxes. Moquegua Region million). In addition, the Company has committed S/ 86.9 million (approximately $24.0 million) for the construction of two infrastructure projects in the Moquegua region under the “social investment for taxes” (obras por impuestos) program, which allows the Company to use these amounts as an advance payment of taxes. Power purchase agreements: ● Electroperu S.A.: In June 2014, the Company entered into a power purchase agreement for 120 megawatt (“MW”) with the state power company Electroperu S.A., under which Electroperu S.A. began supplying energy for the Peruvian operations for twenty years starting on April 17, 2017. ● Kallpa Generacion S.A. (“Kallpa”): In July 2014, the Company entered into a power purchase agreement for 120 MW with Kallpa, an independent Israeli owned power company, under which Kallpa will supply energy for the Peruvian operations for ten years starting on April 17, 2017 and ending on April 30, 2027. In May 2016, the Company signed an additional power purchase agreement for a maximum of 80 MW with Kallpa, under which Kallpa began supplying energy for the Peruvian operations related to the Toquepala Expansion and other minor projects for ten years starting on May 1, 2017 and ending after ten years of commercial operation of the Toquepala Expansion or on April 30, 2029; whichever occurs first. Mexican operations Power purchase agreements: ● MGE: In 2012, the Company signed a power purchase agreement with MGE, an indirect subsidiary of Grupo Mexico, to supply power to some of the Company’s Mexican operations through 2032. For further information, please see Note 17 “Related party transactions”. ● Eolica el Retiro, S.A.P.I. de C.V.: In 2013, the Company signed a power purchase agreement with Eolica el Retiro, S.A.P.I de C.V. a windfarm energy producer that is an indirect subsidiary of Grupo Mexico, to supply power to some of the Company’s Mexican operations. For further information, please see Note 17 “Related party transactions”. ● Parque Eolico de Fenicias, S. de R.L. de C.V.: On February 20, 2020, the Company signed a power purchase agreement with Parque Eolico de Fenicias, S. de R.L. de C.V., an indirect subsidiary of Grupo Mexico, to supply 611,400 MWh of power per year to some of the Company´s Mexican operations for 20 years . This agreement will start in January 2021. Corporate operations Commitment for Capital projects: As of December 31, 2020, the Company has committed approximately $365.8 million for the development of its capital investment projects. Tax contingency matters: Tax contingencies are provided for under ASC 740-10-50-15 Uncertain tax position (see Note 7 “Income taxes”).

STOCKHOLDERS' EQUITY_

STOCKHOLDERS' EQUITY:	12 Months Ended
STOCKHOLDERS' EQUITY:	Dec. 31, 2020
STOCKHOLDERS' EQUITY:
STOCKHOLDERS' EQUITY:	NOTE 14—STOCKHOLDERS’ EQUITY Treasury Stock: Activity in treasury stock in the years 2020 and 2019 was as follows (in millions): 2020 2019 Southern Copper common shares Balance as of January 1, $ 2,767.9 $ 2,768.3 Used for corporate purposes (0.4) (0.4) Balance as of December 31, 2,767.5 2,767.9 Parent Company (Grupo Mexico) common shares Balance as of January 1, 281.0 251.3 Other activity, including dividend, interest and foreign currency transaction effect 15.0 29.7 Balance as of December 31, 296.0 281.0 Treasury stock balance as of December 31, $ 3,063.5 $ 3,048.9 SCC shares of common stock in treasury: At December 31, 2020 and 2019, treasury stock holds 111,522,817 shares and 111,537,217 shares of SCC’s common stock with a cost of $2,767.5 million and $2,767.9 million, respectively. The shares of SCC’s common stock held in treasury are used for Director’s stock award plans and available for general corporate purposes. SCC share repurchase program: In 2008, the Company’s Board of Directors (“BOD”) authorized a $500 million share repurchase program that has since been increased by the BOD and is currently authorized to $3 billion. Pursuant to this program, the Company has purchased 119.5 million shares of common stock at a cost of $2.9 billion. These shares are available for general corporate purposes. The Company may purchase additional shares of its common stock from time to time, based on market conditions and other factors. This repurchase program has no expiration date and may be modified or discontinued at any time. There has not been activity in the SCC share repurchase program since the third quarter of 2016. The NYSE closing price of SCC common shares at December 31, 2020 was $65.12 and the maximum number of shares that the Company could purchase at that price is 1.3 million shares. Grupo Mexico’s direct and indirect ownership remains at 88.9% as of December 31, 2020. Directors’ Stock Award Plan: The Company established a stock award compensation plan for certain directors who are not compensated as employees of the Company. Under this plan, participants received 1,200 shares of common stock upon election and 1,200 additional shares following each annual meeting of stockholders thereafter. 600,000 shares of Southern Copper common stock have been reserved for this plan. On April 26, 2018, the Company’s stockholders approved a five-year extension of the Plan until January 28, 2023 and an increase of the shares award from 1,200 to 1,600. The fair value of the award is measured each year at the date of the grant. In 2020 and 2019 the stock-based compensation expense under this plan equaled $0.4 million for each of these years. The activity of this plan for the years ended December 31, 2020 and 2019 was as follows: 2020 2019 Total SCC shares reserved for the plan 600,000 600,000 Total shares granted at January 1, (377,200) (362,800) Granted in the period (14,400) (14,400) Total shares granted at December 31, (391,600) (377,200) Remaining shares reserved 208,400 222,800 Parent Company common shares: At December 31, 2020 and 2019, there were in treasury 87,598,097 and 93,082,532 of Grupo Mexico’s common shares, respectively. Employee Stock Purchase Plan: 2015 Plan: 1 If Grupo Mexico pays dividends on shares during the eight - In the case of voluntary or involuntary resignation/termination of the employee, the Company will pay to the employee the fair market sales price at the date of resignation of the fully paid shares, net of costs and taxes. When the fair market sales value of the shares is higher than the purchase price, the Company will apply a deduction over the amount to be paid to the employee based on a decreasing schedule specified in the plan. In case of retirement or death of the employee, the Company will render the buyer or his legal beneficiary, the fair market sales value as of the date of retirement or death of the shares effectively paid, net of costs and taxes. The stock-based compensation expense for the years ended December 31, 2020, 2019 and 2018 and the unrecognized compensation expense under this plan were as follows (in millions): 2020 2019 2018 Stock based compensation expense $ 0.6 $ 0.6 $ 0.6 Unrecognized compensation expense $ 1.4 $ 2.0 $ 2.6 The following table presents the stock award activity of this plan for the years ended December 31, 2020 and 2019: Unit Weighted Average Shares Grant Date Fair Value Outstanding shares at January 1, 2020 1,379,734 $ 2.63 Granted — Exercised (115,324) $ 2.63 Forfeited — — Outstanding shares at December 31, 2020 1,264,410 $ 2.63 Outstanding shares at January 1, 2019 1,840,336 $ 2.63 Granted — — Exercised (460,602) $ 2.63 Forfeited — — Outstanding shares at December 31, 2019 1,379,734 $ 2.63 2018 Plan: 1 If Grupo Mexico pays dividends on shares during the eight-year period, the participants will be entitled to receive the dividend in cash for all shares that have been fully purchased and paid as of the date that the dividend is paid. If the participant has only partially paid for shares, the entitled dividends will be used to reduce the remaining liability owed for purchased shares. In the case of voluntary or involuntary resignation/termination of the employee, the Company will pay to the employee the fair market sales price at the date of resignation of the fully paid shares, net of costs and taxes. When the fair market sales value of the shares is higher than the purchase price, the Company will apply a deduction over the amount to be paid to the employee based on a decreasing schedule specified in the plan. In case of retirement or death of the employee, the Company will render the buyer or his legal beneficiary, the fair market sales value as of the date of retirement or death of the shares effectively paid, net of costs and taxes. The stock-based compensation expense for the years ended December 31, 2020 and 2019 and the unrecognized compensation expense under this plan were as follows (in millions): 2020 2019 Stock based compensation expense $ 0.7 $ 0.7 Unrecognized compensation expense $ 3.8 $ 4.5 The following table presents the stock award activity of this plan for the years ended December 31, 2020 and 2019: Unit Weighted Average Shares Grant Date Fair Value Outstanding shares at January 1, 2020 4,002,898 $ 1.86 Granted — Exercised (84,440) $ 1.86 Forfeited — Outstanding shares at December 31, 2020 3,918,458 $ 1.86 Outstanding shares at January 1, 2019 2,782,424 $ 1.86 Granted 1,238,169 $ 1.86 Exercised (17,695) $ 1.86 Forfeited — — Outstanding shares at December 31, 2019 4,002,898 $ 1.86 Executive Stock Purchase Plan: Grupo Mexico also offers a stock purchase plan for certain members of its executive management and the executive management of its subsidiaries and certain affiliated companies. Under this plan, participants will receive incentive cash bonuses which are used to purchase shares of Grupo Mexico which are deposited in a trust. Retained earnings: As part of the settlement of claims brought on behalf of the Company and its shareholders against Grupo Mexico, AMC and certain current and former directors (together with Grupo Mexico and AMC, the ‘‘Defendants’’) a dividend of $0.44428 per share was paid on February 21, 2019 to shareholders of record at the close of business on February 11, 2019, other than the Defendants. The settlement dividend, totaling $36.5 million was an obligation of Grupo Mexico and AMC and therefore, has been funded by them. In addition, Grupo Mexico and AMC paid $13.5 million of legal fees. Non-controlling interest: For all the years presented, in the consolidated statement of earnings the income attributable to non-controlling interest is based on the earnings of the Company's Peruvian Branch. The non-controlling interest of the Company’s Peruvian Branch is for investment shares. These shares were generated by legislation in place in Peru from the 1970s through 1991; such legislation provided for the participation of mining workers in the profits of the enterprises for which they worked. This participation was divided between equity and cash. The investment shares included in the non-controlling interest on the consolidated balance sheets reflect outstanding equity distributions made to the Peruvian Branch’s employees. In prior years, the Company acquired some Peruvian investment shares in exchange for newly issued common shares of the Company and through purchases at market value. These acquisitions were accounted for as purchases of non-controlling interests. The excess paid over the carrying value was assigned to intangible assets and is being amortized based on production. As a result of these acquisitions, the remaining investment shareholders hold a 0.71% interest in the Peruvian Branch and are entitled to a pro rata participation in the cash distributions made by the Peruvian Branch. The shares are recorded as a non-controlling interest in the Company's financial statements.

FAIR VALUE MEASUREMENT_

FAIR VALUE MEASUREMENT:	12 Months Ended
FAIR VALUE MEASUREMENT:	Dec. 31, 2020
FAIR VALUE MEASUREMENT:
FAIR VALUE MEASUREMENT:	NOTE 15—FAIR VALUE MEASUREMENT: Subtopic 820-10 of ASC “Fair value measurement and disclosures -Overall” establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy under Subtopic 820-10 are described below: Level 1 -Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. Level 2 -Inputs that are observable, either directly or indirectly, but do not qualify as Level 1 inputs. (i.e., quoted prices for similar assets or liabilities). Level 3 -Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). The carrying amounts of certain financial instruments, including cash and cash equivalents, accounts receivable (other than accounts receivable associated with provisionally priced sales) and accounts payable approximate fair value due to their short maturities. Consequently, such financial instruments are not included in the following table that provides information about the carrying amounts and estimated fair values of other financial instruments that are not measured at fair value in the consolidated balance sheet as of December 31, 2020 and December 31, 2019 (in millions): At December 31, 2020 At December 31, 2019 Carrying Value Fair Value Carrying Value Fair Value Liabilities: Long-term debt level 1 $ 6,193.6 $ 8,692.1 $ 6,190.6 $ 7,675.3 Long-term debt level 2 350.6 385.7 750.2 776.1 Total long-term debt $ 6,544.2 $ 9,077.8 $ 6,940.8 $ 8,451.4 Long-term debt is carried at amortized cost and its estimated fair value is based on quoted market prices classified as Level 1 in the fair value hierarchy except for the cases of the Yankee bonds and the notes due 2022, which qualify as Level 2 in the fair value hierarchy as they are based on quoted priced in market that are not active. Fair values of assets and liabilities measured at fair value on a recurring basis were calculated as of December 31, 2020 and 2019, as follows (in millions): Fair Value at Measurement Date Using: Significant Fair Value Quoted prices in other Significant as of active markets for observable unobservable December 31, identical assets inputs inputs Description 2020 (Level 1) (Level 2) (Level 3) Assets: Short term investment: — $ 410.2 $ 410.2 $ — $ — — Corporate bonds — — — — Asset backed securities 0.3 — 0.3 — Mortgage backed securities 0.3 — 0.3 — Accounts receivable: — — Provisionally priced sales: Copper 491.9 491.9 — — Molybdenum 129.2 129.2 — — Total $ 1,031.9 $ 1,031.3 $ 0.6 $ — Fair Value at Measurement Date Using: Significant Fair Value Quoted prices in other Significant as of active markets for observable unobservable December 31, identical assets inputs inputs Description 2019 (Level 1) (Level 2) (Level 3) Assets: Short term investment: — $ 80.0 $ 80.0 $ — $ — — Corporate bonds — — — — Asset backed securities 0.4 — 0.4 — Mortgage backed securities 0.3 — 0.3 — Accounts receivable: — Provisionally priced sales: Copper 326.5 326.5 — — Molybdenum 126.8 126.8 — — Total $ 534.0 $ 533.3 $ 0.7 $ — The Company’s short-term trading securities investments are classified as Level 1 because they are valued using quoted prices of the same securities as they consist of bonds issued by public companies and publicly traded. The Company’s short-term available-for-sale investments are classified as Level 2 because they are valued using quoted prices for similar investments. The Company’s accounts receivables associated with provisionally priced copper sales are valued using quoted market prices based on the forward price on the LME or on the COMEX. Such value is classified within Level 1 of the fair value hierarchy. Molybdenum prices are established by reference to the publication Platt’s Metals Week and are considered Level 1 in the fair value hierarchy.

CONCENTRATION OF RISK

CONCENTRATION OF RISK	12 Months Ended
CONCENTRATION OF RISK	Dec. 31, 2020
CONCENTRATION OF RISK:
CONCENTRATION OF RISK:	NOTE 16—CONCENTRATION OF RISK: The Company operates four open-pit copper mines, five underground poly-metallic mines, two smelters and ten refineries in Peru and Mexico and substantially all of its assets are located in these countries. No assurances can be made that any operations and assets of the Company that are subject to the jurisdiction of the governments of Peru and Mexico will not be adversely affected by future actions of such governments. Much of the Company’s products are exported from Peru and Mexico to customers principally in the United States, Europe, Asia and South America. Financial instruments, which potentially subject the Company to a concentration of credit risk, consist primarily of cash and cash equivalents, short-term investments and trade accounts receivable. The Company invests or maintains available cash with various banks, principally in the United States, Mexico, Europe and Peru, or in commercial papers of highly-rated companies. As part of its cash management process, the Company regularly monitors the relative credit standing of these institutions. At December 31, 2020, SCC had invested its cash and cash equivalents and short-term investments as follows: $ in % of total % in one institution Country million cash (1) of country of total cash United States $ 1,968.8 75.9 % 14.1 % 10.7 % Switzerland 340.3 13.1 % 79.4 % 10.4 % Peru 35.5 1.4 % 81.4 % 1.1 % Mexico 249.8 9.6 % 53.8 % 5.2 % Total cash and short-term investment $ 2,594.4 100.0 % (1) 97% of the Company’s cash is in U.S. dollars. During the normal course of business, the Company provides credit to its customers. Although the receivables resulting from these transactions are not collateralized, the Company has not experienced significant problems with the collection of receivables. The Company’s largest customers as percentage of accounts receivable and total sales were as follows: 2020 2019 2018 Accounts receivable trade as of December 31, Five largest customers 35.3 % 37.6 % 34.2 % Largest customer 12.9 % 13.0 % 10.9 % Total sales in year Five largest customers 28.1 % 28.0 % 28.4 % Largest customer 10.0 % 10.4 % 9.3 %

RELATED PARTY TRANSACTIONS_

RELATED PARTY TRANSACTIONS:	12 Months Ended
RELATED PARTY TRANSACTIONS:	Dec. 31, 2020
RELATED PARTY TRANSACTIONS:
RELATED PARTY TRANSACTIONS:	NOTE 17—RELATED PARTY TRANSACTIONS: The Company has entered into certain transactions in the ordinary course of business with parties that are controlling shareholders or their affiliates. These transactions include the lease of office space, air and railroad transportation, construction services, energy supply, and other products and services related to mining and refining. The Company lends and borrows funds among affiliates for acquisitions and other corporate purposes. These financial transactions bear interest and are subject to review and approval by senior management, as are all related party transactions. Article Nine of the Amended and Restated Certificate of Incorporation of the Company prohibits the Company from engaging in a Material Affiliate Transaction that was not the subject of prior review by a committee of the Board of Directors with at least three members, each of whom is independent, and defines a Material Affiliate Transaction as a transaction or series of related transactions between Grupo Mexico or one of its affiliates (other than the Company or its subsidiaries), on the one hand, and the Company or one of its subsidiaries, on the other hand, that involves consideration of more than $10.0 million in the aggregate. It is the Company’s policy that (i) a Material Affiliate Transaction not be entered into or continued without the review and approval by the Audit Committee or its subcommittee of related party transactions comprised of independent directors,(ii) any potential related party transaction process with aggregate consideration between $8.0 million and $10.0 million be authorized by the General Counsel and Chief Financial Officer of the Company and (iii) all related party transactions, including any Material Affiliate Transaction, be reported to the Audit Committee of the Board of Directors or to its subcommittee of related party transactions. Receivable and payable balances with related parties are shown below (in millions): At December 31, 2020 2019 Related parties receivable current: Grupo Mexico and affiliates: Asarco LLC $ 5.3 $ 10.8 AMMINCO Apoyo Administrativo, S.A. de C.V. (“AMMINCO”) — 0.1 Compania Perforadora Mexico S.A.P.I. de C.V. and affiliates 0.3 0.3 Grupo Mexico 2.7 2.7 Mexico Generadora de Energia S. de R.L. ("MGE") 14.4 15.3 Grupo Mexico Servicios de Ingenieria, S.A. de C.V. 0.2 0.2 Related to the controlling group: Boutique Bowling de Mexico S.A. de C.V. 0.2 0.1 Mexico Transportes Aereos, S.A. de C.V. ("Mextransport") — 0.4 Operadora de Cinemas S.A. de C.V. 0.2 0.1 $ 23.3 $ 30.0 Related parties receivable non-current: Grupo Mexico and affiliates: Asarco LLC $ — 59.5 Related parties payable: Grupo Mexico and affiliates: Asarco LLC $ 13.9 $ 4.3 AMMINCO 19.6 16.9 Eolica El Retiro, S.A.P.I. de C.V. 0.3 — Ferrocarril Mexicano S.A. de C.V. 4.7 6.4 Grupo Mexico 0.9 1.1 MGE 40.8 40.2 Mexico Compania Constructora S.A de C.V. 22.9 16.0 Grupo Mexico Servicios de Ingenieria, S.A. de C.V. 0.7 — Related to the controlling group: 0.3 0.2 Mexico Transportes Aereos S.A. de C.V. (“Mextransport”) 0.1 1.2 Operadora de Cinemas S.A. de C.V. 0.1 0.1 $ 104.3 $ 86.4 Purchase and sale activity: Grupo Mexico and affiliates: The following table summarizes the purchase and sale activities with Grupo Mexico and its affiliates in 2020, 2019 and 2018 (in millions): 2020 2019 2018 Purchase activity Asarco LLC $ 233.9 $ 37.6 $ 37.2 AMMINCO 18.6 17.8 8.0 Eolica El Retiro, S.A.P.I. de C.V. 1.0 2.9 3.6 Ferrocarril Mexicano, S.A. de C.V. 45.8 44.1 41.7 Grupo Mexico 10.0 10.0 10.1 MGE 213.3 202.2 200.1 Mexico Compania Constructora S.A de C.V. 42.6 60.3 72.9 Grupo Mexico Servicios de Ingenieria, S.A. de C.V. 11.1 10.7 6.9 Total purchases $ 576.3 $ 385.6 $ 380.5 Sales activity Asarco LLC $ 77.9 $ 11.3 $ 81.8 AMMINCO 0.1 0.1 0.3 Ferrocarril Mexicano, S.A. de C.V. — 0.1 — MGE 54.9 47.4 68.2 Total sales $ 132.9 $ 58.9 $ 150.3 Grupo Mexico, the parent and the majority indirect stockholder of the Company, and its affiliates provide various services to the Company. These services are primarily related to accounting, legal, tax, financial, treasury, human resources, price risk assessment and hedging, purchasing, procurement and logistics, sales and administrative and other support services. The Company pays Grupo Mexico and AMMINCO, a subsidiary of Grupo Mexico, for these services and expects to continue requiring these services in the future. In 2020 and 2019, the Company donated $7.1 million and $9.6 million, respectively, to Fundacion Grupo Mexico,A.C., an organization dedicated to promoting the social and economic development of the communities close to the Company’s Mexican operations. The Company’s Mexican operations paid fees for freight services provided by Ferrocarril Mexicano, S.A de C.V. and for construction services provided by Mexico Compania Constructora S.A. de C.V., which are all subsidiaries of Grupo Mexico. Additionally, the Company´s Peruvian and Mexican operations paid fees for engineering services provided by Grupo Mexico Servicios de Ingenieria, S.A. de C.V., a subsidiary of Grupo Mexico. The Company’s Mexican operations purchased copper concentrate and anodic slimes from Asarco LLC and also paid fees for tolling services. Additionally, the Company´s Mexican operations purchased power from MGE. Both companies are subsidiaries of Grupo Mexico. In 2012, the Company signed a power purchase agreement with MGE, whereby MGE will supply some of the Company’s Mexican operations with power through 2032. MGE has two natural gas-fired combined cycle power generating units, with a net total capacity of 516.2 megawatts and has been supplying power to the Company since December 2013. Currently, MGE is supplying 2.3% of its power output to third-party energy users; compared to 5.2% at December 31, 2019. In 2014, Mexico Generadora de Energia Eolica, S. de R.L. de C.V, an indirect subsidiary of Grupo Mexico, located in Oaxaca, Mexico, acquired Eolica el Retiro, a windfarm with 37 wind turbines. This company started operations in January 2014 and began to sell power to Industrial Minera Mexico, S.A. de C.V. and subsidiaries (IMMSA) and other subsidiaries of Grupo Mexico in the third quarter of 2014. Currently, Eolica el Retiro is supplying approximately 9.6% of its power output to IMMSA; compared to 18.2% at December 31, 2019. The Company sold copper concentrate as well as sulfuric acid, silver and gold to Asarco LLC. In addition, in 2020 and 2019, the Company´s Mexican operations received rental fees from AMMINCO. In 2018, the Company´s Mexican operations sold vehicles to AMMINCO. In 2019, the Company´s Mexican operations sold an asset to Ferrocarril Mexicano, S.A. de C.V. In September 2019, Asarco LLC signed a promissory agreement to pay to the Company´s Mexican operations $62.0 million plus interest no later than October 31, 2021, with quarterly payments of $0.5 million. The annual interest rate of the note was Libor plus 200 basis points, which would be reviewed annually. In November 2020, Asarco repaid this agreement. Related to this agreement, the Company recorded interest income of $2.2 and $2.3 million in 2020 and 2019, respectively. The Company also received fees for natural gas and services provided to MGE, a subsidiary of Grupo Mexico. In May 2020, MGE signed a promissory note to pay to the Company´s Mexican operations 97.2 million Mexican pesos (approximately $5.1 million) plus interest. The annual interest rate of the note was 8.28% with monthly payments. MGE repaid this note in December 2020. Companies with relationships with the controlling group: The following table summarizes the purchase and sales activities with other Larrea family companies in 2020, 2019 and 2018 (in millions): 2020 2019 2018 Purchase activity Boutique Bowling de Mexico S.A. de C.V. $ 0.4 $ 0.4 $ 0.3 Mextransport 3.5 2.3 12.4 Operadora de Cinemas S.A. de C.V. 0.2 0.2 0.2 Total purchases $ 4.1 $ 2.9 $ 12.9 Sales activity Boutique Bowling de Mexico S.A. de C.V. $ 0.1 $ 0.1 $ 0.2 Empresarios Industriales de Mexico, S.A. de C.V. — 0.2 — Mextransport 1.7 1.8 1.2 Operadora de Cinemas S.A. de C.V. 0.1 0.1 0.1 Total sales $ 1.9 $ 2.2 $ 1.5 The Larrea family controls a majority of the capital stock of Grupo Mexico, and has extensive interests in other businesses, including transportation, real estate and entertainment. The Company engages in certain transactions in the ordinary course of business with other entities controlled by the Larrea family relating to the lease of office space, air transportation and entertainment. The Company’s Mexican operations paid fees for entertainment services provided by Boutique Bowling de Mexico S.A de C.V. and Operadora de Cinemas S.A. de C.V. Both companies are controlled by the Larrea family. MexTransport provides aviation services to the Company’s Mexican operations. This is a company controlled by the Larrea family. In addition, the Company received fees for building rental and maintenance services provided to Boutique Bowling de Mexico S.A de C.V. and Operadora de Cinemas S.A. de C.V. The Company´s Mexican operations received fees from Mextransport for reimbursement of maintenance expenses and for rental services. In 2019, The Company´s Mexican operations received fees for security services provided to Empresarios Industriales de Mexico, S.A. de C.V. This is also a company controlled by the Larrea family. Equity Investment in Affiliate: In addition, the Company has a 30.0% participation in Apu Coropuna S.R.L. (“Apu Coropuna”), which it accounts for on the equity method. Apu Coropuna is a company, which undertakes exploration activities in the Pucay prospect, located in Arequipa, Peru. It is anticipated that in the future the Company will enter into similar transactions with these same parties. Companies with relationships with SCC executive officers: In 2020, 2019 and 2018, the Company engaged in no purchase or sales activities with companies that have relationships with SCC executive officers.

SEGMENT AND RELATED INFORMATION

SEGMENT AND RELATED INFORMATION:	12 Months Ended
SEGMENT AND RELATED INFORMATION:	Dec. 31, 2020
SEGMENT AND RELATED INFORMATION:
SEGMENT AND RELATED INFORMATION:	NOTE 18—SEGMENT AND RELATED INFORMATION: Company management views Southern Copper as having three reportable segments and manages it on the basis of these segments. The reportable segments identified by the Company are: the Peruvian operations, the Mexican open-pit operations and the Mexican underground mining operations segment identified as the IMMSA unit. The three reportable segments identified are groups of mines, each of which constitute an operating segment, with similar economic characteristics, type of products, processes and support facilities, similar regulatory environments, similar employee bargaining contracts and similar currency risks. In addition, each mine within the individual group earns revenues from similar type of customers for their products and services and each group incurs expenses independently, including commercial transactions between groups. Intersegment sales are based on arm’s length prices at the time of sale. These may not be reflective of actual prices realized by the Company due to various factors, including additional processing, timing of sales to outside customers and transportation cost. Added to the segment data is information regarding the Company’s sales. The segments identified by the Company are: 1. Peruvian operations, which include the Toquepala and Cuajone mine complexes and the smelting and refining plants, including a precious metals plant, industrial railroad and port facilities that service both mines. The Peruvian operations produce copper, with production of by-products of molybdenum, silver and other material. 2. Mexican open-pit operations, which include La Caridad and Buenavista mine complexes and the smelting and refining plants, including a precious metals plant and a copper rod plant and support facilities that service both mines. The Mexican open-pit operations produce copper, with production of by-products of molybdenum, silver and other material. 3. Mexican underground mining operations, which include five underground mines that produce zinc, copper, silver and gold, and a zinc refinery. This group is identified as the IMMSA unit. The Peruvian operations include two open-pit copper mines whose mineral output is transported by rail to Ilo, Peru where it is processed at the Company’s Ilo smelter and refinery, without distinguishing between the products of the two mines. The resulting product, anodes and refined copper, are then shipped to customers throughout the world. These shipments are recorded as revenue of the Company’s Peruvian mines. The Mexican open-pit segment includes two copper mines whose mineral output is processed in the same smelter and refinery without distinguishing between the products of the two mines. The resultant product, anodes and refined copper, are then shipped to customers throughout the world. These shipments are recorded as revenues of the Company’s Mexican open-pit mines. The Company has determined that it is necessary to classify the Peruvian open-pit operations as an operating segment that is separate from the Mexican open-pit operations due to the very distinct regulatory and political environments in which they operate. The Company’s Chief Operating Decision Maker (“CODM”) must consider the operations in each country separately when analyzing results of the Company and making key decisions. The open-pit mines in Peru must comply with stricter environmental rules and must deal with a political climate that has a very distinct vision of the mining industry than that seen in Mexico. In addition, the collective bargaining agreement contracts are negotiated differently in each of the countries. These key differences result in the Company taking varying decisions with regard to open-pit operations in the two countries. The IMMSA segment includes five mines whose minerals are processed in the same refinery. Sales of product from this segment are recorded as revenues of the Company’s IMMSA unit. While the Mexican underground mines are subject to a regulatory environment that is very similar to that applicable to Mexican open-pit mines, the nature of the products and processes of the two Mexican operations vary considerably. These differences cause the Company’s CODM to take a very different approach when analyzing results and making decisions regarding the two Mexican operations. Financial information is regularly prepared for each of the three segments and the results of the Company’s operations are regularly reported to the CODM on the segment basis. The CODM of the Company focuses on operating income and on total assets as measures of performance to evaluate different segments and to make decisions to allocate resources to the reported segments. These are common measures in the mining industry. Financial information relating to Company’s segments is as follows: Year Ended December 31, 2020 (in millions) Mexican Corporate, other Mexican IMMSA Peruvian and Open-pit Unit Operations eliminations Consolidated Net sales outside of segments $ 4,412.4 $ 418.9 $ 3,153.6 $ — $ 7,984.9 Intersegment sales 111.0 (111.0) — Cost of sales (exclusive of depreciation, amortization and depletion) 1,991.6 383.0 1,679.5 (124.3) 3,929.8 Selling, general and administrative 70.5 9.5 37.6 8.6 126.2 Depreciation, amortization and depletion 366.7 42.5 328.7 37.7 775.6 Exploration 2.5 8.6 9.4 12.1 32.6 Operating income $ 1,981.1 $ 86.3 $ 1,098.4 $ (45.1) 3,120.7 Less: Interest, net (347.4) Other income (expense) (27.5) Income taxes (1,174.4) Equity earnings of affiliate 6.4 Non-controlling interest (7.4) Net income attributable to SCC $ 1,570.4 Capital investment $ 317.1 $ 72.1 $ 195.0 $ 8.0 $ 592.2 Property and mine development, net $ 4,470.5 $ 548.2 $ 3,735.1 $ 704.9 $ 9,458.7 Total assets $ 7,236.1 $ 967.2 $ 5,169.9 $ 3,573.3 $ 16,946.5 Year Ended December 31, 2019 (in millions) Mexican Corporate, other Mexican IMMSA Peruvian and Open-pit Unit Operations eliminations Consolidated Net sales outside of segments $ 3,963.9 $ 381.6 $ 2,940.1 $ — $ 7,285.6 Intersegment sales — 83.2 — (83.2) — Cost of sales (exclusive of depreciation, amortization and depletion) 1,613.1 380.3 1,702.1 (89.1) 3,606.4 Selling, general and administrative 78.6 7.9 38.5 6.8 131.8 Depreciation, amortization and depletion 351.9 52.3 328.1 32.1 764.4 Exploration 1.8 9.0 16.5 2.7 30.0 Operating income $ 1,918.5 $ 15.3 $ 854.9 $ (35.7) 2,753.0 Less: Interest, net (319.5) Other income (expense) (7.0) Income taxes (945.3) Equity earnings of affiliate 10.7 Non-controlling interest (6.1) Net income attributable to SCC $ 1,485.8 Capital investment $ 244.3 $ 106.3 $ 350.1 $ 6.8 $ 707.5 Property and mine development, net $ 4,648.5 $ 497.1 $ 3,879.2 $ 346.2 $ 9,371.0 Total assets $ 8,081.9 $ 837.6 $ 5,017.9 $ 2,470.0 $ 16,407.4 Year Ended December 31, 2018 (in millions) Mexican Corporate, other Mexican IMMSA Peruvian and Open-pit Unit Operations eliminations Consolidated Net sales outside of segments $ 4,075.9 $ 448.6 $ 2,572.2 $ — $ 7,096.7 Intersegment sales — 79.3 — (79.3) — Cost of sales (exclusive of depreciation, amortization and depletion) 1,611.0 377.2 1,509.4 (88.6) 3,409.0 Selling, general and administrative 55.3 8.5 36.7 2.1 102.6 Depreciation, amortization and depletion 360.4 47.6 237.4 28.9 674.3 Exploration 2.0 5.3 18.5 3.8 29.6 Operating income $ 2,047.2 $ 89.3 $ 770.2 $ (25.5) 2,881.2 Less: Interest, net (261.1) Other income (expense) (30.7) Income taxes (1,053.5) Equity earnings of affiliate 12.3 Non-controlling interest (5.2) Net income attributable to SCC $ 1,543.0 Capital investment $ 266.8 $ 60.0 $ 774.0 $ 20.6 $ 1,121.4 Property and mine development, net $ 4,783.8 $ 448.3 $ 3,797.2 $ 374.5 $ 9,403.8 Total assets $ 8,165.2 $ 930.2 $ 4,813.1 $ 379.1 $ 14,287.6 The following table presents information regarding the opening and closing balances of receivables by reporting segment of the Company for the three years ended December 31, 2020 (in millions): Mexican Mexican IMMSA Peruvian Corporate & Open-Pit Unit Operations Elimination Consolidated As of December 31, 2020: Trade receivables $ 566.0 $ 57.8 $ 445.1 $ — $ 1,068.9 Related parties, current 15.4 — 0.8 7.1 23.3 As of December 31, 2019: Trade receivables $ 477.8 $ 38.0 $ 317.1 $ — $ 832.9 Related parties, current 22.1 — — 7.9 30.0 Related parties, non-current 59.5 — — — 59.5 As of December 31, 2018: Trade receivables $ 505.9 $ 50.5 $ 266.0 $ — $ 822.4 Related parties 81.6 — — 19.9 101.5 SALES VALUE PER SEGMENT: The following table presents information regarding the sales value by reporting segment of the Company’s significant products for the three years ended December 31, 2020 (in millions): Year Ended December 31, 2020 Mexican Mexican IMMSA Peruvian Corporate, Other & Total Open-pit Unit Operations Eliminations Consolidated Copper $ 3,762.1 $ 72.1 $ 2,727.3 $ (48.4) $ 6,513.1 Molybdenum 275.2 — 235.1 — 510.3 Zinc — 247.8 — 1.6 249.4 Silver 235.5 155.8 112.0 (55.5) 447.8 Other 139.6 54.2 79.2 (8.7) 264.3 Total $ 4,412.4 $ 529.9 $ 3,153.6 $ (111.0) $ 7,984.9 Year Ended December 31, 2019 Mexican Mexican IMMSA Peruvian Corporate, Other & Total Open-pit Unit Operations Eliminations Consolidated Copper $ 3,314.9 $ 42.0 $ 2,535.3 $ (46.9) $ 5,845.3 Molybdenum 341.0 — 208.4 — 549.4 Zinc — 280.1 — (2.3) 277.8 Silver 185.9 82.7 85.6 (29.9) 324.3 Other 122.1 60.0 110.8 (4.1) 288.8 Total $ 3,963.9 $ 464.8 $ 2,940.1 $ (83.2) $ 7,285.6 Year Ended December 31, 2018 Mexican Mexican IMMSA Peruvian Corporate, Other & Total (in millions) Open-pit Unit Operations Eliminations Consolidated Copper $ 3,459.1 $ 45.6 $ 2,251.2 $ (48.1) $ 5,707.8 Molybdenum 342.5 — 167.4 — 509.9 Zinc — 328.7 — (0.1) 328.6 Silver 175.3 83.5 69.5 (28.1) 300.2 Other 99.0 70.1 84.1 (3.0) 250.2 Total $ 4,075.9 $ 527.9 $ 2,572.2 $ (79.3) $ 7,096.7 NET SALES AND GEOGRAPHICAL INFORMATION: The geographic breakdown of the Company’s sales for the three years ended December 31, 2020 was as follows (in millions): Year Ended December 31, 2020 Mexican Mexican IMMSA Peruvian Corporate & Open-Pit Unit Operations Elimination Consolidated The Americas: Mexico $ 1,296.6 $ 341.1 $ — $ (111.0) $ 1,526.7 United States 1,182.8 27.2 153.4 — 1,363.4 Peru — 13.0 322.0 — 335.0 Brazil — 18.7 214.3 — 233.0 Chile 18.8 — 202.3 — 221.1 Other American countries 36.8 2.9 2.7 — 42.4 Europe: Switzerland 898.2 69.9 475.2 — 1,443.3 Italy 0.1 9.5 262.0 — 271.6 Spain 199.4 — — — 199.4 Other European countries 199.9 40.2 281.6 — 521.7 Asia: Singapore 319.9 6.9 536.9 — 863.7 Japan 46.9 — 532.6 — 579.5 Other Asian countries 213.0 0.5 170.6 384.1 Total $ 4,412.4 $ 529.9 $ 3,153.6 $ (111.0) $ 7,984.9 Year Ended December 31, 2019 Mexican Mexican IMMSA Peruvian Corporate & Open-Pit Unit Operations Elimination Consolidated The Americas: Mexico $ 1,262.2 $ 352.9 $ — $ (83.2) $ 1,531.9 United States 1,054.9 6.2 134.5 — 1,195.6 Peru 1.6 — 338.4 — 340.0 Brazil — 17.3 194.4 — 211.7 Chile 1.2 — 190.1 — 191.3 Other American countries 37.6 2.2 3.3 — 43.1 Europe: Switzerland 780.9 36.7 355.8 — 1,173.4 Italy 45.1 13.3 238.6 — 297.0 Spain 186.1 — — — 186.1 Other European countries 92.8 24.9 256.9 — 374.6 Asia: Singapore 345.4 10.4 611.1 — 966.9 Japan 59.9 — 440.9 — 500.8 Other Asian countries 96.2 0.9 176.1 — 273.2 Total $ 3,963.9 $ 464.8 $ 2,940.1 $ (83.2) $ 7,285.6 Year Ended December 31, 2018 Mexican Mexican IMMSA Peruvian Corporate & Open-Pit Unit Operations Elimination Consolidated The Americas: Mexico $ 1,343.0 $ 385.6 $ — $ (79.3) $ 1,649.3 United States 1,008.0 6.6 244.0 — 1,258.6 Peru — — 390.4 — 390.4 Brazil — 43.8 228.1 — 271.9 Chile — — 136.3 — 136.3 Other American countries 60.6 3.8 1.4 — 65.8 Europe: Switzerland 453.3 43.4 156.7 — 653.4 Italy 20.6 21.7 305.0 — 347.3 Spain 169.4 — — — 169.4 Other European countries 234.8 19.9 124.9 — 379.6 Asia: Singapore 528.8 2.2 538.2 — 1,069.2 Japan 71.8 — 411.6 — 483.4 Other Asian countries 185.6 0.9 35.6 — 222.1 Total $ 4,075.9 $ 527.9 $ 2,572.2 $ (79.3) $ 7,096.7 PROVISIONAL SALES PRICE: At December 31, 2020, the Company has recorded provisionally priced sales of copper at average forward prices per pound, and molybdenum at the year-end market price per pound. These sales are subject to final pricing based on the average monthly copper prices on the London Metal Exchange (“LME”) or New York Commodities Exchange (“COMEX”) and Dealer Oxide molybdenum prices in the future month of settlement. Following are the provisionally priced copper and molybdenum sales outstanding at December 31, 2020: Sales volume Priced at (million lbs.) (per pound) Month of settlement Copper 139.8 3.52 January through April 2021 Molybdenum 12.9 10.03 January through March 2021 Provisional sales price adjustments included in accounts receivable and net sales were as follows at December, 31 (in millions): At December 31, 2020 2019 Copper $ 17.4 $ 4.0 Molybdenum 14.1 (8.2) Total $ 31.5 $ (4.2) Management believes that the final pricing of these sales will not have a material effect on the Company’s financial position or results of operations. LONG-TERM SALES CONTRACTS: The following are the significant outstanding long-term contracts: In 2019, a three-year copper cathodes sales agreement was signed with Mitsui, with shipments beginning in 2020. Mitsui and the Company will negotiate market terms and conditions for annual contracts no later than November 30 of the year prior to shipment. The contract considers the following annual volumes of copper cathodes; 48,000 tons for each of the years from 2020 through 2022. Failure to reach an agreement on market terms would cancel the annual contract but not the long-term agreement. Under the terms of the agreement all shipments would be to Asia and no exclusivity rights for Mitsui or commissions are included. This contract may be renewed for additional years, upon the agreement of both parties. Under the terms of a sales contract with Molymet Group (Molibdenos y Metales, S.A. and Sadaci N.V.), SPCC Peru Branch is required to supply approximately 70% of the molybdenum concentrates production from 2019 through 2022. The sale price of the molybdenum concentrate is based on the average of the High and Low “Daily Dealer Oxide” as published in “Platt’s Metals Daily”. The roasting charge deduction is agreed based on international market terms. Under the terms of a sales contract with Molymex, S.A. de C.V., Operadora de Minas de Nacozari, S.A. de C.V. and Operadora de Minas e Instalaciones Mineras, S.A. de C. V. are required to supply at least the 80% of their molybdenum concentrates production from 2020 through 2023. The sale price of the molybdenum concentrate is based on the average of the High and Low “Daily Dealer Oxide” as published in “Platt’s Metals Daily.” The roasting charge deduction is negotiated based on international market terms.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	12 Months Ended
SUBSEQUENT EVENTS	Dec. 31, 2020
SUBSEQUENT EVENTS:
SUBSEQUENT EVENTS:	NOTE 19—SUBSEQUENT EVENTS: DIVIDENDS: On January 21, 2021, the Board of Directors authorized a dividend of $0.60 per share to be paid

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts and Reserves	12 Months Ended
	Dec. 31, 2020
Schedule II Valuation and Qualifying Accounts and Reserves
Schedule II Valuation and Qualifying Accounts and Reserves	Valuation and Qualifying Accounts and Reserves (in millions): Additions Balance at Charged to beginning of costs and Deduction/ Balance at period expenses Additions Application end of period Reserve deducted in balance sheet to which applicable: Accounts Receivable: 2020 $ 0.5 8.5 — (0.2) $ 8.8 2019 $ 0.5 — — — $ 0.5 2018 $ 1.1 — — (0.6) $ 0.5 Notes issued under par: 2020 $ 69.6 2.0 — — $ 67.6 2019 $ 58.8 1.9 12.7 — $ 69.6 2018 $ 60.5 1.7 — — $ 58.8 Valuation allowance: 2020 $ 1,097.0 246.2 — — $ 1,343.2 2019 $ 819.1 277.9 — — $ 1,097.0 2018 $ 619.6 199.5 — — $ 819.1

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES: (Policies)	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES: (Policies)	Dec. 31, 2020
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:
Principles of consolidation	Principles of consolidation— The consolidated financial statements include the accounts of subsidiaries of which the Company has voting control, in accordance with Accounting Standards Codification (“ASC”) 810 Consolidation
Use of estimates	Use of estimates— The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Significant items subject to such estimates and assumptions include the carrying value of ore reserves that are the basis for future cash flow estimates and amortization calculations; environmental reclamation, closure and retirement obligations; estimates of recoverable copper in mill and leach stockpiles; asset impairments (including estimates of future cash flows); unrecognized tax benefits; valuation allowances for deferred tax assets; and fair value of financial instruments. Management bases its estimates on the Company's historical experience and on various other assumptions that are believed to be reasonable under the circumstances. Actual results could differ from those estimates.
Revenue recognition	Revenue recognition— The Company accounts for a contract with a customer when there is a legally enforceable contract between the Company and the customer, the rights of the parties are identified, the contract has commercial substance, and collectability of the contract consideration is probable. The Company's revenues are measured based on consideration specified in the contract with each customer. Disclosures regarding disaggregation of revenues and contract balances are disclosed within Note 18 "Segment and related information". The Company’s marketing strategy and annual sales planning emphasize developing and maintaining long-term customer relationships. Generally, 80% to 90% of the Company’s metal production is sold under annual or longer-term contracts, which specify a volume of mineral to be sold over a stated period and delivery schedule; the price at which mineral will be sold at each delivery date is generally determined by the weekly or monthly average rate of the commodity published by major metal exchanges at specific dates stipulated within each contract. The Company considers each contract to be a single performance obligation, represented by the delivery of a series of distinct goods that are substantially the same, with the same pattern of transfer to the Company’s customers. The Company concluded this as, based on the nature of its contracts, customers receive the benefit of mineral sold as it is shipped per the terms of the contracts at each contractual delivery date. Likewise, each shipment of product represents the same measure of progress as other shipments within the contract. Accordingly, the Company recognizes revenues for each contract over the period of time in which the specified quantity of mineral is delivered. In doing so, the Company considers that it has a right to consideration from its customers in an amount that corresponds directly to the value transferred to those customers that being the quantity of mineral delivered at the price per unit delivered. Accordingly, the Company recognizes revenue at the amount to which it has the right to invoice (the invoice practical expedient), as it believes that this method is a faithful depiction of the transfer of goods to its customers. For contracts with a term greater than one year, the Company is unable to disclose an allocation of the transaction price to the remaining unsatisfied performance obligation, given that unit prices of mineral sold are determined by published commodity prices at specified dates within the contract. The volume of mineral to be delivered after the first year of the contract is subject to annual volume negotiations in accordance with the terms of the contract. As of December 31, 2020, the Company has long-term contracts with promises to deliver in 2021 for a total of 208,000 metric tons of copper concentrate, 48,000 metric tons of copper cathodes, 43,329 tons of molybdenum concentrate and 325,700 tons of sulfuric acid. This is an estimate that will vary in 2022 and 2023 based on the negotiations with the customers as mentioned above. The remainder of the Company’s revenues, including its by-product revenues, are generated by spot sales that are recognized at a point in time. Under both sales models, revenue is recognized when or as the performance obligations are satisfied, when the Company transfers control of the goods and title passes to the customer. Considering the International Commercial Terms (Incoterms) utilized by the Company, control is transferred generally upon the completion of loading the material at the point of origin. This is the point at which the customer obtains legal title to the product as well as the ability to direct the use of and obtain substantially all of the remaining benefits of ownership of the asset. Additionally, payment is generally due upon the delivery of the shipping and title documents at the point of origin, customers typically have 30 days to remit payment. Copper and non-copper revenues are measured based on the monthly average of prevailing commodity prices according to the terms of the contracts. The Company provides allowances for doubtful accounts based upon historical bad debt and claims experience and periodic evaluation of specific customer accounts. Substantially all of the Company’s sales are made under carriage and insurance paid to, or cost, insurance and freight Incoterms, whereby the Company is responsible for providing shipping and insurance after control of the inventory has been transferred to the customer. According to the terms of the Company’s contracts, these services are not distinct within the context of the contract, and they are not separately identifiable from the other promises within the contract. Additionally, it is the Company policy and it has a long-standing history of providing shipping and insurance services to its customers. Accordingly, shipping and insurance are not considered separate performance obligations. The related costs of shipping and insurance are presented within the cost of sales line in the accompanying consolidated statements of income. Furthermore, the Company considered the impact of the shipping and insurance services on the determination of when control is transferred to its customers. It has concluded that the terms of these services do not impact its customers’ ability to sell, pledge, or otherwise use the products in shipment. Also, there is a small likelihood and minimal history of lost or damaged goods during shipment. Considering these factors, combined with the other indicators of control previously mentioned, the Company has concluded that these services do not impact the determination that control is transferred at the point of origin. For certain of the Company’s sales of copper and molybdenum products, customer contracts allow for pricing based on a month subsequent to shipping, in most cases within the following three months and occasionally in some cases a few additional months. In such cases, revenue is recorded at a provisional price at the time of shipment. The provisionally priced copper sales are adjusted to reflect forward LME or COMEX copper prices at the end of each month until a final adjustment is made to the price of the shipments upon settlement with customers pursuant to the terms of the contract. In the case of molybdenum sales, for which there are no published forward prices, the provisionally priced sales are adjusted to reflect the market prices at the end of each month until a final adjustment is made to the price of the shipments upon settlement with customers pursuant to the terms of the contract. These provisional pricing arrangements are accounted for separately from the contract as an embedded derivative instrument under ASC 815-30 “Derivatives and Hedging—Cash Flow Hedges.” The Company sells copper in concentrate, anode, blister and refined form at industry standard commercial terms. Net sales include the invoiced value of copper, zinc, silver, molybdenum, sulfuric acid and other metals and the corresponding fair value adjustment of the related forward contract of copper and molybdenum. Disclosure regarding adjustments to sales for provisionally priced contracts is disclosed within Note 18 “Segment and related information”.
Cash and cash equivalents	Cash and cash equivalents— Cash and cash equivalents include bank deposits, certificates of deposit and short-term investment funds with original maturities of three months or less at the date of purchase. The carrying value of cash and cash equivalents approximates fair value.
Short-term investments	Short-term investments— The Company accounts for short-term investments in accordance with ASC 320-10 “Investments Debt and Equity Securities-Recognition.” The Company determines the appropriate classification of all short-term investments as held-to-maturity, available-for-sale or trading at the time of purchase and re-evaluates such classifications as of each balance sheet date. Unrealized gains and losses on available-for-sale investments, net of taxes, are reported as a component of accumulated other comprehensive income (loss) in stockholders’ equity, unless such loss is deemed to be other than temporary.
Inventories	Inventories— The Company principally produces copper and, in the production process, obtains several by-products, including molybdenum, silver, zinc, sulfuric acid and other metals. Metal inventories, consisting of work-in-process and finished goods, are carried at the lower of average cost or net realizable value (NRV). Costs of work-in-process inventories and finished goods mainly include power, labor, fuel, operating and repair materials, depreciation, amortization, depletion, and other necessary costs related to the extraction and processing of ore, including mining, milling, concentrating, smelting, refining, leaching and chemical processing. Costs incurred in the production of metal inventories exclude general and administrative costs. Once molybdenum, silver, zinc and other by-products are identified, they are transferred to their respective production facilities and the incremental cost required to complete production is assigned to their inventory value. Work-in-process inventories represent materials that are in the process of being converted into a saleable product. Conversion processes vary depending on the nature of the copper ore and the specific mining operation. For sulfide ores, processing includes milling and concentrating and results in the production of copper and molybdenum concentrates. Finished goods include saleable products (e.g., copper concentrates, copper anodes, copper cathodes, copper rod, molybdenum concentrate and other metallurgical products). Supplies inventories are carried at the lower of average cost or net realizable value (NRV).
Long-term inventory - Ore stockpiles on leach pads	Long-term inventory-Ore stockpiles on leach pads. The leaching process is an integral part of the mining operations carried out at the Company’s open-pit mines. The Company capitalizes the production cost of leachable material at its Toquepala, La Caridad and Buenavista mines, recognizing it as inventory. This cost includes mining and haulage costs incurred to deliver ore to leach pads, depreciation, amortization, depletion and site overhead costs. The estimates of recoverable mineral content contained in the leaching dumps are supported by engineering studies. As the production cycle of the leaching process is significantly longer than the conventional process of concentrating, smelting and electrolytic refining, the Company includes current leach inventory (included in work-in-process inventories) and long-term leach inventory on its balance sheet. On January 1, 2020, the Company aligned its capitalization method for its Peruvian and Mexican operations to capitalize based on the allocation of copper content recoverable between ore and leach material. In addition, inventory consumption is now valued at the average unit cost, instead of the declining percentages of recovery method used previously. As a result of these changes, during 2020 the value of capitalized material decreased by $196.4 million and consumption decreased by $29.3 million when compared to the previous capitalization method. Management has evaluated ASC 250-10 and considered appropriate guidance to conclude that the aforementioned classifies as a change in accounting estimate, and therefore should affect accounting books prospectively. Management believes that this new method will result in a more accurate valuation of this material.
Property	Property— Property is recorded at acquisition cost, net of accumulated depreciation and amortization. Cost includes major expenditures for improvements and replacements, which extend useful lives or increase capacity and interest costs associated with significant capital additions. Maintenance, repairs, normal development costs at existing mines and gains or losses on assets retired or sold are reflected in earnings as incurred. Buildings and equipment are depreciated on the straight-line method over estimated lives from two
Mine development	Mine development — Mine development includes primarily the cost of acquiring land rights to an exploitable ore body, pre-production stripping costs at new mines that are commercially exploitable, costs associated with bringing new mineral properties into production, and removal of overburden to prepare unique and identifiable areas outside the current mining area for such future production. Mine development costs are amortized on a unit of production basis over the remaining life of the mines. Diverse practices exist in the mining industry relative to the treatment of drilling and other related costs to delineate new ore reserves. The Company follows the practices outlined in the next two paragraphs in its treatment of drilling and related costs. Drilling and other associated costs incurred in the Company's efforts to delineate new resources, whether near-mine or Greenfield are expensed as incurred. These costs are classified as mineral exploration costs. Once the Company determines through feasibility studies that proven and probable reserves exist and that the drilling and other associated costs embody a probable future benefit that involves a capacity, singly or in combination with other assets, to contribute directly or indirectly to future net cash inflow, then the costs are classified as mine development costs. These mine development costs incurred prospectively to develop the property are capitalized as incurred, until the commencement of production, and are amortized using the units of production method over estimated life of the ore body. During the production stage, drilling and other related costs incurred to maintain production are included in production cost in the period in which they are incurred. Drilling and other related costs incurred in the Company’s efforts to delineate a major expansion of reserves at an existing production property are expensed as incurred. Once the Company determines through feasibility studies that proven and probable incremental reserves exist and that the drilling and other associated costs embody a probable future benefit that involves a capacity, singly or in combination with other assets, to contribute directly or indirectly to future net cash inflow, then the costs are classified as mine development costs. These incremental mine development costs are capitalized as incurred, until the commencement of production and amortized using the units of production method over the estimated life of the ore body. A major expansion of reserves is one that increases total reserves at a property by approximately 10% or more. For the years ended December 31, 2020, 2019 and 2018, the Company did not capitalize any drilling and related costs.
Asset retirement obligations (reclamation and remediation costs)	Asset retirement obligations (reclamation and remediation costs)— The fair value of a liability for asset retirement obligations is recognized in the period in which the liability is incurred. The liability is measured at fair value and is adjusted to its present value in subsequent periods as accretion expense is recorded. The corresponding asset retirement costs are capitalized as part of the carrying value of the related long-lived assets and depreciated over the asset's useful life.
Intangible assets	Intangible assets— Intangible assets include primarily the excess amount paid over the book value for investment shares, which are presented as mining concessions, and mining and engineering development studies. Intangible assets are carried at acquisition costs, net of accumulated amortization and are amortized principally on a unit of production basis over the estimated remaining life of the mines. Intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable.
Debt issuance costs	Debt issuance costs— Debt issuance costs related to a recognized debt liability are presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with the treatment of a debt discount.
Ore reserves	Ore reserves— The Company periodically reevaluates estimates of its ore reserves, which represent the Company’s estimate as to the amount of unmined copper remaining in its existing mine locations that can be produced and sold at a profit. Such estimates are based on engineering evaluations derived from samples of drill holes and other openings, combined with assumptions about copper market prices and production costs at each of the respective mines. The Company updates its estimate of ore reserves at the beginning of each year. In this calculation, the Company uses current metal prices which are defined as the average metal price over the preceding three years. The current price per pound of copper, as defined, was $2.816, $2.818 and $2.642 at the end of 2020, 2019 and 2018, respectively. The ore reserve estimates are used to determine the amortization of mine development and intangible assets. Once the Company determines through feasibility studies that proven and probable reserves exist and that drilling and other associated costs embody a probable future benefit that involves a capacity, singly or in combination with other assets, to contribute directly or indirectly to future net cash inflow, then the costs are classified as mine development costs and the Company discloses the related ore reserves.
Exploration	Exploration— Tangible and intangible costs incurred in the search for mineral properties are charged against earnings when incurred.
Income taxes	Income taxes— Provisions for income taxes are based on taxes payable or refundable for the current year and deferred taxes on temporary differences between the amount of taxable income and pretax financial income and between the tax bases of assets and liabilities and their reported amounts in the financial statements. Deferred tax assets and liabilities are included in the financial statements at currently enacted income tax rates applicable to the period in which the deferred tax assets and liabilities are expected to be realized and settled as prescribed in ASC 740 “Income taxes.” As changes in tax laws or rates are enacted, deferred tax assets and liabilities are adjusted through the provision for income taxes. Deferred income tax assets are reduced by any benefits that, in the opinion of management, are more likely not to be realized. The Company’s operations involve dealing with uncertainties and judgments in the application of complex tax regulations in multiple jurisdictions. The final taxes paid are dependent upon many factors, including negotiations with tax authorities in various jurisdictions and resolution of disputes arising from federal, state, and international tax audits. The Company recognizes potential liabilities and records tax liabilities for anticipated tax audit issues in the U.S. and other tax jurisdictions based on its estimate of whether, and the extent to which, additional taxes will be due. The Company follows the guidance of ASC 740 “Income taxes” to record these liabilities. (See Note 7 “Income taxes” of the consolidated financial statements for additional information). The Company adjusts these reserves in light of changing facts and circumstances; however, due to the complexity of some of these uncertainties, the ultimate resolution may result in a payment that is materially different from the Company’s current estimate of the tax liabilities. If its estimate of tax liabilities proves to be less than the ultimate assessment, an additional charge to expense would result. If payment of these amounts ultimately proves to be less than the recorded amounts, the reversal of the liabilities would result in tax benefits being recognized in the period when the Company determines the liabilities are no longer necessary. The Company classifies income tax-related interest and penalties as income taxes in the financial statements, as well as interest and penalties, if any, related to unrecognized tax benefits.
Foreign exchange	Foreign exchange— The Company’s functional currency is the U.S. dollar. As required by local law, both the Peruvian Branch and Minera Mexico maintain their books of accounts in Peruvian soles and Mexican pesos, respectively. Foreign currency assets and liabilities are remeasured into U.S. dollars at current exchange rates, except for non-monetary items such as inventory, property, intangible assets and other assets which are remeasured at historical exchange rates. Revenues and expenses are generally translated at actual exchange rates in effect during the period, except for those items related to balance sheet amounts that are remeasured at historical exchange rates. Gains and losses from foreign currency remeasurement are included in earnings of the period. Gains and (losses) resulting from foreign currency transactions are included in "Cost of sales (exclusive of depreciation, amortization and depletion)."
Asset impairments	Asset impairments - The Company evaluates long-term assets when events or changes in economic circumstances indicate that the carrying amount of such assets may not be recoverable. These evaluations are based on business plans that are prepared using a time horizon that is reflective of the Company’s expectations of metal prices over its business cycle. The Company is currently using a long-term average copper price and an average molybdenum price for impairment tests, reflective of what the Company believes is the lower level of the current price environment. The results of its impairment tests using these long-term copper and molybdenum prices show no impairment in the carrying value of their assets. In recent years testing using assumptions for long-term average prices have resulted in stricter evaluation for impairment analysis than would the higher three year average prices for copper and molybdenum prices. Should this situation reverse in the future with three - -
Other comprehensive income	Other comprehensive income— Comprehensive income represents changes in equity during a period, except those resulting from investments by owners and distributions to owners. During the fiscal years ended December 31, 2020, 2019 and 2018, the components of "other comprehensive income (loss)" were, the unrecognized gain (loss) on employee benefit obligations and foreign currency translation adjustments.
Business segments	Business segments- Company management views Southern Copper as having three reportable segments and manages it on the basis of these segments. The segments identified by the Company are: 1) the Peruvian operations, which include the two open-pit copper mines in Peru and the plants and services supporting such mines, 2) the Mexican open-pit copper mines, which include La Caridad and Buenavista mine complexes and their supporting facilities and 3) the Mexican underground mining operations, which include five underground mines that produce zinc, lead, copper, silver and gold, a coal mine and a zinc refinery. Please see Note 18 “Segments and Related Information.” The Chief Operating Decision Maker of the Company focuses on operating income as measure of performance to evaluate different segments, and to make decisions to allocate resources to the reported segments. This is a common measure in the mining industry.
Leases	Leases - The Company adopted FASB ASC 842, Leases, effective January 1, 2019. The Company determined if a contract is or contained a lease at its inception. The Company evaluated if a contract gave the right to obtain substantially all of the economic benefits from use of an identified asset and the right to direct the use of the asset, in order to determine if a contract contained a lease. All of the Company’s existing lease contracts are operating lease contracts. For these leases, the Company recognized right-of-use assets and the corresponding operating lease liabilities on its consolidated balance sheet. Right-of-use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent an obligation by the Company to make lease payments which arise from the lease. Lease right-of-use assets and liabilities are recognized at the inception date based on the present value of lease payments over the lease term. As the Company’s lease contracts do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at the inception date in order to determine the present value of lease payments. Lease expense for lease payments is recognized on a straight-line basis over the lease term, in the cost of sales and operating expenses. The Company elected the transition approach whereby it applied the new leases standard at the adoption date and recognized a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. The Company elected the short-term lease recognition exemption (short-term lease practical expedient) by class of underlying asset (which results in off-balance-sheet accounting for the lease).
Credit losses	ADOPTION OF CREDIT LOSSES STANDARD In June 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-13: “Financial Instruments – Credit Losses (Topic 326)”. This ASU was adopted on January 1, 2020. Prior to adopting this ASU, the Company applied an impairment methodology for accounts receivable arising from revenue transactions within the scope of ASC 606 that is consistent with the provision matrix model contemplated in the new standard. In addition, the new disclosure requirements do not apply to such trade receivables because the collection periods in all cases are less than one year. The Company’s accounts receivable from related parties under common control are excluded from the scope of this ASU. Accordingly, the adoption of this ASU did not have a material impact on the Company’s financial statements or related disclosures.

SHORT-TERM INVESTMENTS_ (Tables

SHORT-TERM INVESTMENTS: (Tables)	12 Months Ended
SHORT-TERM INVESTMENTS: (Tables)	Dec. 31, 2020
SHORT-TERM INVESTMENTS:
Schedule of short-term investments	Short-term investments were as follows ($ in millions): At December 31, 2020 2019 Trading securities $ 410.2 $ 80.0 Weighted average interest rate 0.4 % 2.0 % Available-for-sale $ 0.6 $ 0.7 Weighted average interest rate 0.7 % 0.7 % Total $ 410.8 $ 80.7
Summary of activity investments	The following table summarizes the activity of these investments by category (in millions): Years ended December 31, 2020 2019 Trading: Interest earned $ 0.7 $ 0.6 Unrealized gain (loss) at the end of the period $ () $ () Available-for-sale: Interest earned () () Investment redeemed $ 0.1 $ — (*) Less than $0.1 million
Schedule of contractual maturities of the Company's available-for-sale debt securities	At December 31, 2020 and 2019, contractual maturities of the available-for-sale debt securities are as follows (in millions): 2020 2019 One year or less $ — $ — Maturing after one year through five years — — Maturing after five years through ten years — — Due after 10 years 0.6 0.7 Total debt securities $ 0.6 $ 0.7

INVENTORIES_ (Tables)

INVENTORIES: (Tables)	12 Months Ended
INVENTORIES: (Tables)	Dec. 31, 2020
INVENTORIES:
Schedule of inventories	At December 31, (in millions) 2020 2019 Inventory, current: Metals at average cost: Finished goods $ 50.8 $ 87.2 Work-in-process 248.9 259.7 Ore stockpiles on leach pads 298.5 358.4 Supplies at average cost 352.0 363.2 Total current inventory $ 950.2 $ 1,068.5 Inventory, long-term: Ore stockpiles on leach pads $ 1,125.0 $ 1,230.3

PROPERTY_ (Tables)

PROPERTY: (Tables)	12 Months Ended
PROPERTY: (Tables)	Dec. 31, 2020
PROPERTY:
Schedule of major classes of property, plant and equipment	At December 31, (in millions) 2020 2019 Buildings and equipment $ 15,561.9 $ 15,016.1 Construction in progress 1,481.6 1,294.8 Mine development 272.8 267.5 Mineral assets 83.2 83.2 Land, other than mineral 235.8 200.1 Total property 17,635.3 16,861.7 Accumulated depreciation, amortization and depletion (8,176.6) (7,490.7) Total property and mine development, net $ 9,458.7 $ 9,371.0

INTANGIBLE ASSETS_ (Tables)

INTANGIBLE ASSETS: (Tables)	12 Months Ended
INTANGIBLE ASSETS: (Tables)	Dec. 31, 2020
INTANGIBLE ASSETS:
Schedule of major classes of intangible assets and goodwill	At December 31, (in millions) 2020 2019 Mining concessions $ 121.2 $ 121.2 Mine engineering and development studies 19.8 19.8 Software 60.6 55.9 201.6 196.9 Accumulated amortization: Mining concessions (38.6) (38.0) Mine engineering and development studies (17.2) (16.3) Software (44.7) (36.1) (100.5) (90.4) Goodwill 41.9 41.9 Intangible assets, net $ 143.0 $ 148.4
Schedule of estimated amortization of intangible assets for future periods	Estimated amortization expense (in millions): 2021 $ 7.7 2022 5.2 2023 5.2 2024 4.3 2025 3.0 Total 2021 - 2025 $ 25.4 Average annual $ 5.1

INCOME TAXES_ (Tables)

INCOME TAXES: (Tables)	12 Months Ended
INCOME TAXES: (Tables)	Dec. 31, 2020
INCOME TAXES:
Components of the provision for income taxes	(in millions) 2020 2019 2018 U.S. federal and state: Current $ — $ — $ 2.6 Deferred — — (13.0) Uncertain tax positions — (1.3) — — (1.3) (10.4) Foreign (Peru and Mexico): Current 1,237.9 966.3 1,102.4 Deferred (63.5) (30.1) (38.5) Uncertain tax positions — 10.4 — 1,174.4 946.6 1,063.9 Total provision for income taxes $ 1,174.4 $ 945.3 $ 1,053.5
Schedule of source of income	(in millions) 2020 2019 2018 Earnings by location: U.S. $ (15.3) $ (1.9) $ (2.3) Foreign Peru 723.9 513.0 441.8 Mexico 2,037.2 1,915.4 2,149.9 2,761.1 2,428.4 2,591.7 Earnings before taxes on income $ 2,745.8 $ 2,426.5 $ 2,589.4
Reconciliation of the statutory income tax rate to the effective tax rate	The reconciliation of the statutory income tax rate to the effective tax rate for the three years ended December 31, 2020, is as follows (in percentage points): 2020 2019 2018 Expected tax at U.S. statutory rate 21.0 % 21.0 % 21.0 % Foreign tax at other than statutory rate, net of foreign tax credit benefit (1) 13.7 14.0 13.9 Percentage depletion (2.2) (2.7) (2.1) Other permanent differences 0.1 0.1 0.4 Change in 2017 valuation allowance on U.S. deferred tax assets, foreign tax credits and U.S. tax effect on Peruvian deferred taxes — — 7.5 Additional valuation allowance on 2018 U.S. deferred tax assets, foreign tax credits and U.S. tax effect on Peruvian deferred taxes 8.9 10.1 1.0 Decrease in 2017 U.S. deferred tax asset due to tax rate changes — — (0.2) U.S. one time transition tax on accumulated foreign earnings — — 0.4 Increase (decrease) in unrecognized tax benefits for uncertain tax positions (0.1) (2.1) — Amounts (over) / under provided in prior years (0.1) (1.1) (1.3) Other 1.5 (0.3) 0.1 Effective income tax rate 42.8 % 39.0 % 40.7 % (1) Foreign tax at other than statutory rates, net of foreign tax credit benefit, also includes the effects of permanent differences in Peru and Mexico, that are determined at the local statutory rate.
Schedule of deferred tax assets and liabilities	At December 31, (in millions) 2020 2019 Assets: Inventories $ 62.4 $ 55.7 Capitalized exploration expenses 13.0 14.0 U.S. foreign tax credit carryforward, net of FIN 48 liability 974.1 731.8 U.S. tax effect of Peruvian deferred tax liability 111.2 131.3 Provisions 169.5 145.0 Mexican tax on consolidated dividends — 9.0 Deferred workers participation 37.8 24.7 Accrued salaries, wages and vacations 8.5 10.0 Sales price adjustment (PUI) (5.8) 3.0 Social responsibility expenses 4.3 2.1 Deferred charges 41.8 14.5 Valuation allowance on U.S. deferred tax assets, foreign tax credits and U.S. tax effect on Peruvian deferred (1,343.2) (1,097.0) Other 19.5 9.9 Total deferred tax assets 93.1 54.0 At December 31, (in millions) 2020 2019 Liabilities: Property, plant and equipment (17.2) (45.4) Other (5.3) (3.0) Total deferred tax liabilities (22.5) (48.4) Total net deferred tax (liabilities) / assets $ 70.6 $ 5.6
Summary of expiry of foreign tax credits	Year Amount 2023 39.4 2024 102.0 2025 189.5 2026 107.0 2027 — 2028 159.6 2029 204.9 2030 237.6 Total $ 1,040.0
Schedule of reconciliation of amount of unrecognized tax benefits	The total amount of unrecognized tax benefits in 2020, 2019 and 2018, was as follows (in millions): 2020 2019 2018 Unrecognized tax benefits, opening balance $ 58.4 $ 214.5 $ 214.5 Gross increases—tax positions in prior period — (7.5) — Gross increases—current-period tax positions 7.7 (4.2) — Decreases related to settlements with taxing authorities — (144.4) — 7.7 (156.1) — Unrecognized tax benefits, ending balance $ 66.1 $ 58.4 $ 214.5
Summary of tax years remaining open to examination and adjustment in major tax jurisdictions	Peru: 2014 and all subsequent years U.S.: 2014 and all subsequent years Mexico: 2015 and all subsequent years

WORKERS' PARTICIPATION_ (Tables

WORKERS' PARTICIPATION: (Tables)	12 Months Ended
WORKERS' PARTICIPATION: (Tables)	Dec. 31, 2020
WORKERS' PARTICIPATION:
Schedule of workers' participation expense	Workers’ participation expense for the three years ended December 31, 2020 was as follows (in millions): 2020 2019 2018 Current $ 248.5 $ 188.8 $ 219.9 Deferred 19.8 29.8 9.8 $ 268.3 $ 218.6 $ 229.7

LEASES_ (Tables)

LEASES: (Tables)	12 Months Ended
LEASES: (Tables)	Dec. 31, 2020
LEASES:
Schedule of the operating lease expense recognized	The operating lease expense recognized in the years ended December 31, 2020 and 2019 was classified as follows (in millions): Classification 2020 2019 Cost of sales (exclusive of depreciation, amortization and depletion) $ 114.4 $ 114.4 Selling, general and administrative 0.2 0.2 Exploration 0.2 0.2 Total lease expense $ 114.8 $ 114.8
Schedule of Maturities of lease liabilities	Lease liabilities Year (in millions) 2021 $ 114.7 2022 113.7 2023 112.3 2024 104.7 2025 103.7 After 2025 723.0 Total lease payments $ 1,272.1 Less: interest on lease liabilities (293.1) Present value of lease payments $ 979.0

ASSET RETIREMENT OBLIGATION_ (T

ASSET RETIREMENT OBLIGATION: (Tables)	12 Months Ended
ASSET RETIREMENT OBLIGATION: (Tables)	Dec. 31, 2020
ASSET RETIREMENT OBLIGATION:
Summary of asset retirement obligation activity	The following table summarizes the asset retirement obligation activity for the years ended December 31, 2020 and 2019 (in millions): 2020 2019 Balance as of January 1 $ 262.3 $ 217.7 Changes in estimates 269.3 36.4 Closure payments (1.2) (5.3) Accretion expense 14.6 13.5 Balance as of December 31, $ 545.0 $ 262.3

FINANCING_ (Tables)

FINANCING: (Tables)	12 Months Ended
FINANCING: (Tables)	Dec. 31, 2020
FINANCING:
Schedule of long-term debt	Long-term debt (in millions): Carrying value as of Face Issuance Issuance December 31, amount discount costs 2020 3.500% Senior unsecured notes due 2022 $ 300 (0.2) $ (0.3) $ 299.5 3.875% Senior unsecured notes due 2025 500 (1.3) (1.2) 497.5 9.250% Yankee bonds due 2028 51.2 — — 51.2 7.500% Senior unsecured notes due 2035 1,000 (12.0) (8.0) 980.0 6.750% Senior unsecured notes due 2040 1,100 (6.9) (5.6) 1,087.5 5.250% Senior unsecured notes due 2042 1,200 (18.6) (6.2) 1,175.2 5.875% Senior unsecured notes due 2045 1,500 (16.1) (8.5) 1,475.4 4.500% Minera Mexico Senior unsecured notes due 2050 1,000 (12.5) (9.6) 977.9 Total $ 6,651.2 $ (67.6) $ (39.4) 6,544.2 Less, current portion — Total long-term debt $ 6,544.2 Carrying value as of Face Issuance Issuance December 31, amount discount costs 2019 5.375% Senior unsecured notes due 2020 $ 400 (0.1) $ (0.1) $ 399.8 3.500% Senior unsecured notes due 2022 300 (0.3) (0.5) 299.2 3.875% Senior unsecured notes due 2025 500 (1.6) (1.5) 496.9 9.250% Yankee bonds due 2028 51 — — 51.2 7.500% Senior unsecured notes due 2035 1,000 (12.4) (8.3) 979.3 6.750% Senior unsecured notes due 2040 1,100 (7.1) (5.7) 1,087.2 5.250% Senior unsecured notes due 2042 1,200 (19.0) (6.3) 1,174.7 5.875% Senior unsecured notes due 2045 1,500 (16.4) (8.6) 1,475.0 4.500% Minera Mexico Senior unsecured notes due 2050 1,000 (12.7) (9.8) 977.5 Total $ 7,051 $ (69.6) $ (40.8) 6,940.8 Less, current portion (399.8) Total long-term debt $ 6,541.0
Schedule of aggregate maturities of the outstanding borrowings	Principal Years Due() (in millions) 2021 $ — 2022 300.0 2023 — 2024 — 2025 500.0 Thereafter 5,851.2 Total $ 6,651.2 ()

BENEFIT PLANS_ (Tables)

BENEFIT PLANS: (Tables)	12 Months Ended
BENEFIT PLANS: (Tables)	Dec. 31, 2020
Post retirement defined benefit plans and defined contribution plan
Components of net periodic benefit costs
Schedule of the components of net periodic benefit costs	(in millions) 2020 2019 2018 Service cost $ 1.4 $ 1.1 $ 1.0 Interest cost 1.7 1.8 1.6 Expected return on plan assets (2.9) (3.5) (3.4) Amortization of net actuarial loss 0.1 — — Amortization of prior service cost / (credit) 0.2 0.2 0.2 Settlement / Curtailment (0.4) — (0.2) Amortization of net loss/(gain) 0.2 0.3 0.2 Net periodic benefit cost $ 0.3 $ (0.1) $ (0.6)
Schedule of changes in the benefit obligation and plan assets, the funded status of the plans and the amount recognized in balance sheet and accumulated other comprehensive income	As of December 31, (in millions) 2020 2019 Change in benefit obligation: Projected benefit obligation at beginning of year $ 33.7 $ 27.4 Service cost 1.4 1.1 Interest cost 1.7 1.8 Settlement — — Benefits paid (1.9) (1.8) Actuarial (gain)/loss (4.2) 3.6 Actuarial gain assumption changes 0.8 0.9 Inflation adjustment (1.6) 0.7 Projected benefit obligation at end of year $ 29.9 $ 33.7 Change in plan assets: Fair value of plan assets at beginning of year $ 51.6 $ 46.7 Actual return on plan assets 6.5 4.8 Employer contributions (0.6) (0.6) Benefits paid (0.9) (0.9) Currency exchange rate adjustment (2.2) 1.6 Fair value of plan assets at end of year $ 54.4 $ 51.6 Funded status at end of year: $ 24.5 $ 17.9 ASC-715 amounts recognized in statement of financial position consists of: Non-current assets $ 24.5 $ 17.9 Total $ 24.5 $ 17.9 ASC-715 amounts recognized in accumulated other comprehensive income (net of income taxes of $(2.3) million and $(5.4) million in 2020 and 2019, respectively) consists of: Net loss (gain) $ 3.0 $ 7.6 Prior service cost 1.2 1.4 Total $ 4.2 $ 9.0
Schedule of changes in accumulated other comprehensive income	(in millions) 2020 2019 Reconciliation of accumulated other comprehensive income: Accumulated other comprehensive income at beginning of plan year $ 9.0 $ 7.2 Net loss/(gain) amortized during the year (4.1) 1.9 Net loss/(gain) occurring during the year (0.3) (0.2) Prior service cost (credit) — — Currency exchange rate adjustment (0.4) 0.1 Net adjustment to accumulated other comprehensive income (net of income taxes of $3.1 million and $(2.2) million in 2020 and 2019, respectively) (4.8) 1.8 Accumulated other comprehensive income at end of plan year $ 4.2 $ 9.0
Summary of the amounts in accumulated other comprehensive income amortized and recognized as a component of net periodic benefit cost, net of tax	(in millions) 2020 2019 Net loss / (gain) $ (4.1) $ 1.8 Amortization of net (loss) gain (0.3) (0.2) Amortization of prior services cost (credit) — — Total amortization expenses $ (4.4) $ 1.6
Schedule of assumptions used to determine the pension obligations and other post-retirement benefits	Expatriate Plan 2020 2019 2018 Discount rate 1.90 % 2.85 % 3.90 % Expected long-term rate of return on plan asset 3.50 % 4.00 % 4.00 % Rate of increase in future compensation level N/A N/A N/A Mexican Plan() 2020 2019 2018 Discount rate 7.43 % 7.15 % 8.45 % Expected long-term rate of return on plan asset 7.43 % 7.15 % 8.45 % Rate of increase in future compensation level 4.50 % 4.50 % 4.50 % ()
Scheduled maturities of the benefits expected to be paid in each of the next five years, and thereafter	Expected Years Benefit Payments (in millions) 2021 $ 3.1 2022 1.7 2023 1.8 2024 2.0 2025 1.8 2026 to 2028 12.5 Total $ 22.9
Post-retirement Health care plans
Components of net periodic benefit costs
Schedule of the components of net periodic benefit costs	(in millions) 2020 2019 2018 Interest cost $ 1.3 $ 0.9 $ 0.9 Amortization of prior service cost/ (credit) — (0.2) (0.2) Net periodic benefit cost $ 1.3 $ 0.7 $ 0.7
Schedule of changes in the benefit obligation and plan assets, the funded status of the plans and the amount recognized in balance sheet and accumulated other comprehensive income	As of December 31, (in millions) 2020 2019 Change in benefit obligation: Projected benefit obligation at beginning of year $ 20.6 $ 11.9 Interest cost 1.3 0.9 Actuarial loss/ (gain)-claims cost — — Benefits paid (1.5) (1.3) Actuarial (gain)/loss 4.5 8.6 Inflation adjustment (1.1) 0.5 Projected benefit obligation at end of year $ 23.8 $ 20.6 Change in plan assets: Fair value of plan assets at beginning of year $ — $ — Employer contributions 0.1 0.1 Benefits paid (0.1) (0.1) Fair value of plan assets at end of year $ — $ — Funded status at end of year: $ 23.8 $ 20.6 ASC-715 amounts recognized in statement of financial position consists of: Current liabilities $ — $ (0.1) Non-current liabilities (23.8) (20.5) Total $ (23.8) $ (20.6) ASC-715 amounts recognized in accumulated other comprehensive income consists of: Net loss (gain) $ 4.6 $ 1.5 Total (net of income taxes of $(1.9) million and $(0.7) million in 2020 and 2019, respectively) $ 4.6 $ 1.5
Schedule of changes in accumulated other comprehensive income	As of December 31, (in millions) 2020 2019 Reconciliation of accumulated other comprehensive income: Accumulated other comprehensive income at beginning of plan year $ 1.5 $ (4.4) Net loss/(gain) occurring during the year 3.2 6.0 Net loss/(gain) amortized during the year — 0.1 Currency exchange rate adjustment (0.1) (0.2) Net adjustment to accumulated other comprehensive income (net of income taxes of $(1.2) million and $(2.6) million in 2020 and 2019, respectively) 3.1 5.9 Accumulated other comprehensive income at end of plan year $ 4.6 $ 1.5
Summary of the amounts in accumulated other comprehensive income amortized and recognized as a component of net periodic benefit cost, net of tax	As of December 31, (in millions) 2020 2019 Net loss / (gain) $ 3.2 $ 5.9 Amortization of net (loss) gain — 0.2 Total amortization expenses $ 3.2 $ 6.1
Schedule of assumptions used to determine the pension obligations and other post-retirement benefits	2020 2019 2018 Expatriate health plan Discount rate 1.90 % 2.85 % 3.90 % Mexican health plan Weighted average discount rate 7.43 % 7.15 % 8.45 %
Scheduled maturities of the benefits expected to be paid in each of the next five years, and thereafter	Expected Year Benefit Payments (in millions) 2021 $ 1.5 2022 1.6 2023 1.5 2024 1.5 2025 1.6 2026 to 2030 8.6 Total $ 16.3
Mexican Health Plan \| Post retirement defined benefit plans and defined contribution plan
Components of net periodic benefit costs
Schedule of asset mix of the investment portfolio	2020 2019 Asset category: Treasury bills 78 % 80 % Equity securities 22 % 20 % 100 % 100 %
Mexican Health Plan \| Post-retirement Health care plans
Components of net periodic benefit costs
Schedule of effects of one percentage-point change in assumed other benefits cost trend rates	One Percentage Point (in millions) Increase Decrease Effect on total service and interest cost components $ 1.9 $ 1.5 Effect on the post-retirement benefit obligation $ 24.7 $ 22.2

COMMITMENTS AND CONTINGENCIES_

COMMITMENTS AND CONTINGENCIES: (Tables)	12 Months Ended
COMMITMENTS AND CONTINGENCIES: (Tables)	Dec. 31, 2020
COMMITMENTS AND CONTINGENCIES:
Schedule of environmental capital investments	Environmental capital investments in years 2020, 2019 and 2018, were as follows (in millions): 2020 2019 2018 Peruvian operations () $ (3.3) $ 18.6 $ 59.3 Mexican operations 41.1 64.3 43.5 $ 37.8 $ 82.9 $ 102.8 ()

STOCKHOLDERS' EQUITY (Tables)

STOCKHOLDERS' EQUITY (Tables)	12 Months Ended
STOCKHOLDERS' EQUITY (Tables)	Dec. 31, 2020
Share based Compensation Plan
Schedule of activity in treasury stock	Activity in treasury stock in the years 2020 and 2019 was as follows (in millions): 2020 2019 Southern Copper common shares Balance as of January 1, $ 2,767.9 $ 2,768.3 Used for corporate purposes (0.4) (0.4) Balance as of December 31, 2,767.5 2,767.9 Parent Company (Grupo Mexico) common shares Balance as of January 1, 281.0 251.3 Other activity, including dividend, interest and foreign currency transaction effect 15.0 29.7 Balance as of December 31, 296.0 281.0 Treasury stock balance as of December 31, $ 3,063.5 $ 3,048.9
Schedule of activity in Directors' Stock Award Plan	2020 2019 Total SCC shares reserved for the plan 600,000 600,000 Total shares granted at January 1, (377,200) (362,800) Granted in the period (14,400) (14,400) Total shares granted at December 31, (391,600) (377,200) Remaining shares reserved 208,400 222,800
Employee Stock Purchase 2015 Plan
Share based Compensation Plan
Schedule of stock based compensation expense and unrecognized compensation expense	The stock-based compensation expense for the years ended December 31, 2020, 2019 and 2018 and the unrecognized compensation expense under this plan were as follows (in millions): 2020 2019 2018 Stock based compensation expense $ 0.6 $ 0.6 $ 0.6 Unrecognized compensation expense $ 1.4 $ 2.0 $ 2.6
Schedule of stock award activity	Unit Weighted Average Shares Grant Date Fair Value Outstanding shares at January 1, 2020 1,379,734 $ 2.63 Granted — Exercised (115,324) $ 2.63 Forfeited — — Outstanding shares at December 31, 2020 1,264,410 $ 2.63 Outstanding shares at January 1, 2019 1,840,336 $ 2.63 Granted — — Exercised (460,602) $ 2.63 Forfeited — — Outstanding shares at December 31, 2019 1,379,734 $ 2.63
Employee Stock Purchase 2018 Plan
Share based Compensation Plan
Schedule of stock based compensation expense and unrecognized compensation expense	The stock-based compensation expense for the years ended December 31, 2020 and 2019 and the unrecognized compensation expense under this plan were as follows (in millions): 2020 2019 Stock based compensation expense $ 0.7 $ 0.7 Unrecognized compensation expense $ 3.8 $ 4.5
Schedule of stock award activity	Unit Weighted Average Shares Grant Date Fair Value Outstanding shares at January 1, 2020 4,002,898 $ 1.86 Granted — Exercised (84,440) $ 1.86 Forfeited — Outstanding shares at December 31, 2020 3,918,458 $ 1.86 Outstanding shares at January 1, 2019 2,782,424 $ 1.86 Granted 1,238,169 $ 1.86 Exercised (17,695) $ 1.86 Forfeited — — Outstanding shares at December 31, 2019 4,002,898 $ 1.86

FAIR VALUE MEASUREMENT_ (Tables

FAIR VALUE MEASUREMENT: (Tables)	12 Months Ended
FAIR VALUE MEASUREMENT: (Tables)	Dec. 31, 2020
FAIR VALUE MEASUREMENT:
Schedule of carrying amount and estimated fair values of the Company's financial instruments	Consequently, such financial instruments are not included in the following table that provides information about the carrying amounts and estimated fair values of other financial instruments that are not measured at fair value in the consolidated balance sheet as of December 31, 2020 and December 31, 2019 (in millions): At December 31, 2020 At December 31, 2019 Carrying Value Fair Value Carrying Value Fair Value Liabilities: Long-term debt level 1 $ 6,193.6 $ 8,692.1 $ 6,190.6 $ 7,675.3 Long-term debt level 2 350.6 385.7 750.2 776.1 Total long-term debt $ 6,544.2 $ 9,077.8 $ 6,940.8 $ 8,451.4
Schedule of fair values of assets and liabilities measured at fair value on a recurring basis	Fair values of assets and liabilities measured at fair value on a recurring basis were calculated as of December 31, 2020 and 2019, as follows (in millions): Fair Value at Measurement Date Using: Significant Fair Value Quoted prices in other Significant as of active markets for observable unobservable December 31, identical assets inputs inputs Description 2020 (Level 1) (Level 2) (Level 3) Assets: Short term investment: — $ 410.2 $ 410.2 $ — $ — — Corporate bonds — — — — Asset backed securities 0.3 — 0.3 — Mortgage backed securities 0.3 — 0.3 — Accounts receivable: — — Provisionally priced sales: Copper 491.9 491.9 — — Molybdenum 129.2 129.2 — — Total $ 1,031.9 $ 1,031.3 $ 0.6 $ — Fair Value at Measurement Date Using: Significant Fair Value Quoted prices in other Significant as of active markets for observable unobservable December 31, identical assets inputs inputs Description 2019 (Level 1) (Level 2) (Level 3) Assets: Short term investment: — $ 80.0 $ 80.0 $ — $ — — Corporate bonds — — — — Asset backed securities 0.4 — 0.4 — Mortgage backed securities 0.3 — 0.3 — Accounts receivable: — Provisionally priced sales: Copper 326.5 326.5 — — Molybdenum 126.8 126.8 — — Total $ 534.0 $ 533.3 $ 0.7 $ —

CONCENTRATION OF RISK_ (Tables)

CONCENTRATION OF RISK: (Tables)	12 Months Ended
CONCENTRATION OF RISK: (Tables)	Dec. 31, 2020
CONCENTRATION OF RISK:
Schedule of concentration risk for cash equivalents and short- term investments	$ in % of total % in one institution Country million cash (1) of country of total cash United States $ 1,968.8 75.9 % 14.1 % 10.7 % Switzerland 340.3 13.1 % 79.4 % 10.4 % Peru 35.5 1.4 % 81.4 % 1.1 % Mexico 249.8 9.6 % 53.8 % 5.2 % Total cash and short-term investment $ 2,594.4 100.0 % (1) 97% of the Company’s cash is in U.S. dollars.
Schedule of company's largest customers as percentage of accounts receivable and total sales	2020 2019 2018 Accounts receivable trade as of December 31, Five largest customers 35.3 % 37.6 % 34.2 % Largest customer 12.9 % 13.0 % 10.9 % Total sales in year Five largest customers 28.1 % 28.0 % 28.4 % Largest customer 10.0 % 10.4 % 9.3 %

RELATED PARTY TRANSACTIONS_ (Ta

RELATED PARTY TRANSACTIONS: (Tables)	12 Months Ended
RELATED PARTY TRANSACTIONS: (Tables)	Dec. 31, 2020
RELATED PARTY TRANSACTIONS:
Schedule of receivable and payable balances with related parties	Receivable and payable balances with related parties are shown below (in millions): At December 31, 2020 2019 Related parties receivable current: Grupo Mexico and affiliates: Asarco LLC $ 5.3 $ 10.8 AMMINCO Apoyo Administrativo, S.A. de C.V. (“AMMINCO”) — 0.1 Compania Perforadora Mexico S.A.P.I. de C.V. and affiliates 0.3 0.3 Grupo Mexico 2.7 2.7 Mexico Generadora de Energia S. de R.L. ("MGE") 14.4 15.3 Grupo Mexico Servicios de Ingenieria, S.A. de C.V. 0.2 0.2 Related to the controlling group: Boutique Bowling de Mexico S.A. de C.V. 0.2 0.1 Mexico Transportes Aereos, S.A. de C.V. ("Mextransport") — 0.4 Operadora de Cinemas S.A. de C.V. 0.2 0.1 $ 23.3 $ 30.0 Related parties receivable non-current: Grupo Mexico and affiliates: Asarco LLC $ — 59.5 Related parties payable: Grupo Mexico and affiliates: Asarco LLC $ 13.9 $ 4.3 AMMINCO 19.6 16.9 Eolica El Retiro, S.A.P.I. de C.V. 0.3 — Ferrocarril Mexicano S.A. de C.V. 4.7 6.4 Grupo Mexico 0.9 1.1 MGE 40.8 40.2 Mexico Compania Constructora S.A de C.V. 22.9 16.0 Grupo Mexico Servicios de Ingenieria, S.A. de C.V. 0.7 — Related to the controlling group: 0.3 0.2 Mexico Transportes Aereos S.A. de C.V. (“Mextransport”) 0.1 1.2 Operadora de Cinemas S.A. de C.V. 0.1 0.1 $ 104.3 $ 86.4
Grupo Mexico and affiliates
RELATED PARTY TRANSACTIONS:
Schedule of purchase and sales activities with related parties	The following table summarizes the purchase and sale activities with Grupo Mexico and its affiliates in 2020, 2019 and 2018 (in millions): 2020 2019 2018 Purchase activity Asarco LLC $ 233.9 $ 37.6 $ 37.2 AMMINCO 18.6 17.8 8.0 Eolica El Retiro, S.A.P.I. de C.V. 1.0 2.9 3.6 Ferrocarril Mexicano, S.A. de C.V. 45.8 44.1 41.7 Grupo Mexico 10.0 10.0 10.1 MGE 213.3 202.2 200.1 Mexico Compania Constructora S.A de C.V. 42.6 60.3 72.9 Grupo Mexico Servicios de Ingenieria, S.A. de C.V. 11.1 10.7 6.9 Total purchases $ 576.3 $ 385.6 $ 380.5 Sales activity Asarco LLC $ 77.9 $ 11.3 $ 81.8 AMMINCO 0.1 0.1 0.3 Ferrocarril Mexicano, S.A. de C.V. — 0.1 — MGE 54.9 47.4 68.2 Total sales $ 132.9 $ 58.9 $ 150.3
Related to the controlling group
RELATED PARTY TRANSACTIONS:
Schedule of purchase and sales activities with related parties	The following table summarizes the purchase and sales activities with other Larrea family companies in 2020, 2019 and 2018 (in millions): 2020 2019 2018 Purchase activity Boutique Bowling de Mexico S.A. de C.V. $ 0.4 $ 0.4 $ 0.3 Mextransport 3.5 2.3 12.4 Operadora de Cinemas S.A. de C.V. 0.2 0.2 0.2 Total purchases $ 4.1 $ 2.9 $ 12.9 Sales activity Boutique Bowling de Mexico S.A. de C.V. $ 0.1 $ 0.1 $ 0.2 Empresarios Industriales de Mexico, S.A. de C.V. — 0.2 — Mextransport 1.7 1.8 1.2 Operadora de Cinemas S.A. de C.V. 0.1 0.1 0.1 Total sales $ 1.9 $ 2.2 $ 1.5

SEGMENT AND RELATED INFORMATI_2

SEGMENT AND RELATED INFORMATION: (Tables)	12 Months Ended
SEGMENT AND RELATED INFORMATION: (Tables)	Dec. 31, 2020
SEGMENT AND RELATED INFORMATION:
Schedule of financial information relating to Company's segments	Year Ended December 31, 2020 (in millions) Mexican Corporate, other Mexican IMMSA Peruvian and Open-pit Unit Operations eliminations Consolidated Net sales outside of segments $ 4,412.4 $ 418.9 $ 3,153.6 $ — $ 7,984.9 Intersegment sales 111.0 (111.0) — Cost of sales (exclusive of depreciation, amortization and depletion) 1,991.6 383.0 1,679.5 (124.3) 3,929.8 Selling, general and administrative 70.5 9.5 37.6 8.6 126.2 Depreciation, amortization and depletion 366.7 42.5 328.7 37.7 775.6 Exploration 2.5 8.6 9.4 12.1 32.6 Operating income $ 1,981.1 $ 86.3 $ 1,098.4 $ (45.1) 3,120.7 Less: Interest, net (347.4) Other income (expense) (27.5) Income taxes (1,174.4) Equity earnings of affiliate 6.4 Non-controlling interest (7.4) Net income attributable to SCC $ 1,570.4 Capital investment $ 317.1 $ 72.1 $ 195.0 $ 8.0 $ 592.2 Property and mine development, net $ 4,470.5 $ 548.2 $ 3,735.1 $ 704.9 $ 9,458.7 Total assets $ 7,236.1 $ 967.2 $ 5,169.9 $ 3,573.3 $ 16,946.5 Year Ended December 31, 2019 (in millions) Mexican Corporate, other Mexican IMMSA Peruvian and Open-pit Unit Operations eliminations Consolidated Net sales outside of segments $ 3,963.9 $ 381.6 $ 2,940.1 $ — $ 7,285.6 Intersegment sales — 83.2 — (83.2) — Cost of sales (exclusive of depreciation, amortization and depletion) 1,613.1 380.3 1,702.1 (89.1) 3,606.4 Selling, general and administrative 78.6 7.9 38.5 6.8 131.8 Depreciation, amortization and depletion 351.9 52.3 328.1 32.1 764.4 Exploration 1.8 9.0 16.5 2.7 30.0 Operating income $ 1,918.5 $ 15.3 $ 854.9 $ (35.7) 2,753.0 Less: Interest, net (319.5) Other income (expense) (7.0) Income taxes (945.3) Equity earnings of affiliate 10.7 Non-controlling interest (6.1) Net income attributable to SCC $ 1,485.8 Capital investment $ 244.3 $ 106.3 $ 350.1 $ 6.8 $ 707.5 Property and mine development, net $ 4,648.5 $ 497.1 $ 3,879.2 $ 346.2 $ 9,371.0 Total assets $ 8,081.9 $ 837.6 $ 5,017.9 $ 2,470.0 $ 16,407.4 Year Ended December 31, 2018 (in millions) Mexican Corporate, other Mexican IMMSA Peruvian and Open-pit Unit Operations eliminations Consolidated Net sales outside of segments $ 4,075.9 $ 448.6 $ 2,572.2 $ — $ 7,096.7 Intersegment sales — 79.3 — (79.3) — Cost of sales (exclusive of depreciation, amortization and depletion) 1,611.0 377.2 1,509.4 (88.6) 3,409.0 Selling, general and administrative 55.3 8.5 36.7 2.1 102.6 Depreciation, amortization and depletion 360.4 47.6 237.4 28.9 674.3 Exploration 2.0 5.3 18.5 3.8 29.6 Operating income $ 2,047.2 $ 89.3 $ 770.2 $ (25.5) 2,881.2 Less: Interest, net (261.1) Other income (expense) (30.7) Income taxes (1,053.5) Equity earnings of affiliate 12.3 Non-controlling interest (5.2) Net income attributable to SCC $ 1,543.0 Capital investment $ 266.8 $ 60.0 $ 774.0 $ 20.6 $ 1,121.4 Property and mine development, net $ 4,783.8 $ 448.3 $ 3,797.2 $ 374.5 $ 9,403.8 Total assets $ 8,165.2 $ 930.2 $ 4,813.1 $ 379.1 $ 14,287.6
Schedule of opening and closing balances of receivables by reporting segment	The following table presents information regarding the opening and closing balances of receivables by reporting segment of the Company for the three years ended December 31, 2020 (in millions): Mexican Mexican IMMSA Peruvian Corporate & Open-Pit Unit Operations Elimination Consolidated As of December 31, 2020: Trade receivables $ 566.0 $ 57.8 $ 445.1 $ — $ 1,068.9 Related parties, current 15.4 — 0.8 7.1 23.3 As of December 31, 2019: Trade receivables $ 477.8 $ 38.0 $ 317.1 $ — $ 832.9 Related parties, current 22.1 — — 7.9 30.0 Related parties, non-current 59.5 — — — 59.5 As of December 31, 2018: Trade receivables $ 505.9 $ 50.5 $ 266.0 $ — $ 822.4 Related parties 81.6 — — 19.9 101.5
Schedule of sales value per segment	The following table presents information regarding the sales value by reporting segment of the Company’s significant products for the three years ended December 31, 2020 (in millions): Year Ended December 31, 2020 Mexican Mexican IMMSA Peruvian Corporate, Other & Total Open-pit Unit Operations Eliminations Consolidated Copper $ 3,762.1 $ 72.1 $ 2,727.3 $ (48.4) $ 6,513.1 Molybdenum 275.2 — 235.1 — 510.3 Zinc — 247.8 — 1.6 249.4 Silver 235.5 155.8 112.0 (55.5) 447.8 Other 139.6 54.2 79.2 (8.7) 264.3 Total $ 4,412.4 $ 529.9 $ 3,153.6 $ (111.0) $ 7,984.9 Year Ended December 31, 2019 Mexican Mexican IMMSA Peruvian Corporate, Other & Total Open-pit Unit Operations Eliminations Consolidated Copper $ 3,314.9 $ 42.0 $ 2,535.3 $ (46.9) $ 5,845.3 Molybdenum 341.0 — 208.4 — 549.4 Zinc — 280.1 — (2.3) 277.8 Silver 185.9 82.7 85.6 (29.9) 324.3 Other 122.1 60.0 110.8 (4.1) 288.8 Total $ 3,963.9 $ 464.8 $ 2,940.1 $ (83.2) $ 7,285.6 Year Ended December 31, 2018 Mexican Mexican IMMSA Peruvian Corporate, Other & Total (in millions) Open-pit Unit Operations Eliminations Consolidated Copper $ 3,459.1 $ 45.6 $ 2,251.2 $ (48.1) $ 5,707.8 Molybdenum 342.5 — 167.4 — 509.9 Zinc — 328.7 — (0.1) 328.6 Silver 175.3 83.5 69.5 (28.1) 300.2 Other 99.0 70.1 84.1 (3.0) 250.2 Total $ 4,075.9 $ 527.9 $ 2,572.2 $ (79.3) $ 7,096.7
Schedule of net sales by countries	The geographic breakdown of the Company’s sales for the three years ended December 31, 2020 was as follows (in millions): Year Ended December 31, 2020 Mexican Mexican IMMSA Peruvian Corporate & Open-Pit Unit Operations Elimination Consolidated The Americas: Mexico $ 1,296.6 $ 341.1 $ — $ (111.0) $ 1,526.7 United States 1,182.8 27.2 153.4 — 1,363.4 Peru — 13.0 322.0 — 335.0 Brazil — 18.7 214.3 — 233.0 Chile 18.8 — 202.3 — 221.1 Other American countries 36.8 2.9 2.7 — 42.4 Europe: Switzerland 898.2 69.9 475.2 — 1,443.3 Italy 0.1 9.5 262.0 — 271.6 Spain 199.4 — — — 199.4 Other European countries 199.9 40.2 281.6 — 521.7 Asia: Singapore 319.9 6.9 536.9 — 863.7 Japan 46.9 — 532.6 — 579.5 Other Asian countries 213.0 0.5 170.6 384.1 Total $ 4,412.4 $ 529.9 $ 3,153.6 $ (111.0) $ 7,984.9 Year Ended December 31, 2019 Mexican Mexican IMMSA Peruvian Corporate & Open-Pit Unit Operations Elimination Consolidated The Americas: Mexico $ 1,262.2 $ 352.9 $ — $ (83.2) $ 1,531.9 United States 1,054.9 6.2 134.5 — 1,195.6 Peru 1.6 — 338.4 — 340.0 Brazil — 17.3 194.4 — 211.7 Chile 1.2 — 190.1 — 191.3 Other American countries 37.6 2.2 3.3 — 43.1 Europe: Switzerland 780.9 36.7 355.8 — 1,173.4 Italy 45.1 13.3 238.6 — 297.0 Spain 186.1 — — — 186.1 Other European countries 92.8 24.9 256.9 — 374.6 Asia: Singapore 345.4 10.4 611.1 — 966.9 Japan 59.9 — 440.9 — 500.8 Other Asian countries 96.2 0.9 176.1 — 273.2 Total $ 3,963.9 $ 464.8 $ 2,940.1 $ (83.2) $ 7,285.6 Year Ended December 31, 2018 Mexican Mexican IMMSA Peruvian Corporate & Open-Pit Unit Operations Elimination Consolidated The Americas: Mexico $ 1,343.0 $ 385.6 $ — $ (79.3) $ 1,649.3 United States 1,008.0 6.6 244.0 — 1,258.6 Peru — — 390.4 — 390.4 Brazil — 43.8 228.1 — 271.9 Chile — — 136.3 — 136.3 Other American countries 60.6 3.8 1.4 — 65.8 Europe: Switzerland 453.3 43.4 156.7 — 653.4 Italy 20.6 21.7 305.0 — 347.3 Spain 169.4 — — — 169.4 Other European countries 234.8 19.9 124.9 — 379.6 Asia: Singapore 528.8 2.2 538.2 — 1,069.2 Japan 71.8 — 411.6 — 483.4 Other Asian countries 185.6 0.9 35.6 — 222.1 Total $ 4,075.9 $ 527.9 $ 2,572.2 $ (79.3) $ 7,096.7
Schedule of provisionally priced copper and molybdenum sales outstanding	Sales volume Priced at (million lbs.) (per pound) Month of settlement Copper 139.8 3.52 January through April 2021 Molybdenum 12.9 10.03 January through March 2021
Schedule of provisional sales price adjustments included in accounts receivable and net sales	Provisional sales price adjustments included in accounts receivable and net sales were as follows at December, 31 (in millions): At December 31, 2020 2019 Copper $ 17.4 $ 4.0 Molybdenum 14.1 (8.2) Total $ 31.5 $ (4.2)

DESCRIPTION OF THE BUSINESS_ (D

DESCRIPTION OF THE BUSINESS: (Details) $ in Millions	Apr. 15, 2020USD ($)	Dec. 31, 2020$ / lb$ / item
Percentage of ownership interest held by the parent company		88.90%
Percentage of operating over production capacity during COVID-19 time		0.98%
Copper price assumption \| $ / lb		2
Molybdenum price assumption \| $ / item		4
Minimum
Projected discounted cash flows in excess of the carrying amounts of long lived assets by margins		1.3
Maximum
Projected discounted cash flows in excess of the carrying amounts of long lived assets by margins		4.3
Fixed-rate senior unsecured notes issued April 2010
Repayment of debt \| $	$ 400

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)itemtsegment$ / lb	Dec. 31, 2019$ / lb	Dec. 31, 2018$ / lb
Financial information related to segments
Decrease in inventory capitalized material \| $	$ 196.4
Increase in inventory consumption \| $	$ 29.3
Significant Accounting Policies
Increase in total reserves at a property to qualify as a major expansion (as a percent)	10.00%
Period considered for calculation of average metal price	3 years
Current price of copper (in dollars per pound) \| $ / lb	2.816	2.818	2.642
Impairment in the carrying value of long-term assets \| $	$ 0
Number of years of average prices for copper and molybdenum used for impairment analysis	3 years
Number of reportable segments \| segment	3
Copper concentrates
Significant Accounting Policies
Long-term contracts with promises to deliver mineral	208,000
Copper cathodes
Significant Accounting Policies
Long-term contracts with promises to deliver mineral	48,000
Molybdenum concentrates
Significant Accounting Policies
Long-term contracts with promises to deliver mineral	43,329
Sulfuric acid
Significant Accounting Policies
Long-term contracts with promises to deliver mineral	325,700
Minimum
Financial information related to segments
Estimated useful lives of buildings and equipment	2 years
Significant Accounting Policies
Percentage of metal production sold under annual or longer-term contracts	80.00%
Maximum
Financial information related to segments
Maximum period after shipping within which pricing is based by customer contracts in most cases	3 months
Estimated useful lives of buildings and equipment	50 years
Significant Accounting Policies
Percentage of metal production sold under annual or longer-term contracts	90.00%
Peruvian Operations
Financial information related to segments
Number of open-pit copper mines \| item	2
Mexican IMMSA Unit
Financial information related to segments
Number of underground poly metal mines \| item	5

SHORT-TERM INVESTMENTS_ (Detail

SHORT-TERM INVESTMENTS: (Details) - USD ($) $ in Millions	12 Months Ended
SHORT-TERM INVESTMENTS: (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Short-term investment:
Trading securities	$ 410.2	$ 80
Weighted average interest rate (as a percent)	0.40%	2.00%
Available-for-sale	$ 0.6	$ 0.7
Weighted average interest rate (as a percent)	0.70%	0.70%
Total	$ 410.8	$ 80.7
Trading:
Interest earned	0.7	0.6
Available-for-sale:
Interest earned	19.2	21.2	$ 16
Investment redeemed	0.1
Contractual maturities of available-for-sale debt securities
Due after 10 years	0.6	0.7
Total debt securities	0.6	0.7
Maximum
Available-for-sale:
Interest earned	$ 0.1	$ 0.1

INVENTORIES_ (Details)

INVENTORIES: (Details) - USD ($) $ in Millions	12 Months Ended
INVENTORIES: (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Metals at average cost:
Finished goods	$ 50.8	$ 87.2
Work-in-process	248.9	259.7
Ore stockpiles on leach pads	298.5	358.4
Supplies at average cost	352	363.2
Total current inventory	950.2	1,068.5
Inventory, long-term:
Ore stockpiles on leach pads	1,125	1,230.3
Total leaching costs added as long-term inventory of ore stockpiles in leach pads	194	469	$ 506.6
Long-term leaching inventories recognized as cost of sales	$ 359.1	$ 385.8	$ 299.4

PROPERTY_ (Details)

PROPERTY: (Details) - USD ($) $ in Millions	12 Months Ended
PROPERTY: (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property
Total property	$ 17,635.3	$ 16,861.7
Accumulated depreciation, amortization and depletion	(8,176.6)	(7,490.7)
Total property and mine development, net	9,458.7	9,371	$ 9,403.8
Depreciation and depletion expense	766.4	759.9	$ 668.9
Buildings and equipment
Property
Total property	15,561.9	15,016.1
Construction in progress
Property
Total property	1,481.6	1,294.8
Mine development
Property
Total property	272.8	267.5
Mineral assets
Property
Total property	83.2	83.2
Land, other than mineral
Property
Total property	$ 235.8	$ 200.1

INTANGIBLE ASSETS_ (Details)

INTANGIBLE ASSETS: (Details) - USD ($) $ in Millions	12 Months Ended
INTANGIBLE ASSETS: (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Intangible assets
Intangible assets excluding goodwill, gross	$ 201.6	$ 196.9
Accumulated amortization	(100.5)	(90.4)
Goodwill	41.9	41.9
Intangible assets, net	143	148.4
Amortization expense:
Amortization expense	9.2	4.5	$ 5.4
Estimated amortization expense:
2021	7.7
2022	5.2
2023	5.2
2024	4.3
2025	3
Total 2021-2025	25.4
Average annual	5.1
Buenavista del Cobre, S.A. de C.V
Intangible assets
Goodwill	17
El Pilar
Intangible assets
Goodwill	24.9
Mining concessions
Intangible assets
Intangible assets excluding goodwill, gross	121.2	121.2
Accumulated amortization	(38.6)	(38)
Mine engineering and development studies
Intangible assets
Intangible assets excluding goodwill, gross	19.8	19.8
Accumulated amortization	(17.2)	(16.3)
Software
Intangible assets
Intangible assets excluding goodwill, gross	60.6	55.9
Accumulated amortization	$ (44.7)	$ (36.1)

INCOME TAXES_ - TCJA (Details)

INCOME TAXES: - TCJA (Details)	12 Months Ended
INCOME TAXES: - TCJA (Details)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2009
Income Taxes
Percentage of ownership by parent	88.90%
U.S. statutory rate (as a percent)	21.00%	21.00%	21.00%	35.00%
Maximum percentage of expenses excluding cost of goods sold	3.00%
Minimum
Income Taxes
BEAT tax rate (as a percent)			5.00%
Minimum \| Years 2019 through 2025
Income Taxes
BEAT tax rate (as a percent)	10.00%
Minimum \| Years thereafter
Income Taxes
BEAT tax rate (as a percent)	12.50%
AMC \| Minimum
Income Taxes
Percentage of ownership by parent					80.00%

INCOME TAXES_ - Provision (Deta

INCOME TAXES: - Provision (Details) - USD ($) $ in Millions	12 Months Ended
INCOME TAXES: - Provision (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
U.S. federal and state:
Current			$ 2.6
Deferred			(13)
Uncertain tax positions		$ (1.3)
Provision for income taxes		(1.3)	(10.4)
Foreign (Peru and Mexico):
Current	$ 1,237.9	966.3	1,102.4
Deferred	(63.5)	(30.1)	(38.5)
Uncertain tax position		10.4
Provision for income taxes	1,174.4	946.6	1,063.9
Total provision for income taxes	1,174.4	945.3	1,053.5
Earnings by location:
U.S.	(15.3)	(1.9)	(2.3)
Peru	723.9	513	441.8
Mexico	2,037.2	1,915.4	2,149.9
Foreign	2,761.1	2,428.4	2,591.7
Income before income taxes	$ 2,745.8	$ 2,426.5	$ 2,589.4

INCOME TAXES_ - Effective tax r

INCOME TAXES: - Effective tax rate (Details) - item	12 Months Ended
INCOME TAXES: - Effective tax rate (Details) - item	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of the statutory income tax rate to the effective tax rate
Expected tax at U.S. statutory rate (as a percent)	21.00%	21.00%	21.00%	35.00%
Foreign tax at other than statutory rate, net of foreign tax credit benefit (as a percent)	13.70%	14.00%	13.90%
Percentage depletion (as a percent)	(2.20%)	(2.70%)	(2.10%)
Other permanent differences (as a percent)	0.10%	0.10%	0.40%
Change in 2017 valuation allowance on U.S. deferred tax assets, foreign tax credits and U.S. tax effect on Peruvian deferred taxes			7.50%
Additional valuation allowance on U.S. deferred tax assets, foreign tax credits and U.S. tax effect on Peruvian deferred taxes	8.90%	10.10%	1.00%
Decrease in U.S. deferred tax asset due to tax rate changes			(0.20%)
U.S. one time transition tax on accumulated foreign earnings			0.40%
Increase (decrease) in unrecognized tax benefits for uncertain tax positions (as a percent)	(0.10%)	(2.10%)
Amounts (over) / under provided in prior years	(0.10%)	(1.10%)	(1.30%)
Other (as a percent)	1.50%	(0.30%)	0.10%
Effective income tax rate	42.80%	39.00%	40.70%
Number of jurisdictions where company files income tax returns	3
Duration for which statutory tax rates for Peru and Mexico are considered to determine effective tax rate	3 years
Mexico
Reconciliation of the statutory income tax rate to the effective tax rate
Expected tax at U.S. statutory rate (as a percent)	30.00%	30.00%	30.00%
Peru
Reconciliation of the statutory income tax rate to the effective tax rate
Expected tax at U.S. statutory rate (as a percent)	29.50%	29.50%	29.50%

INCOME TAXES_ - Tax assets and

INCOME TAXES: - Tax assets and liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assets:
Inventories	$ 62.4	$ 55.7
Capitalized exploration expenses	13	14
U.S. foreign tax credit carryforward, net of FIN 48 liability	974.1	731.8
U.S. tax effect of Peruvian deferred tax liability	111.2	131.3
Provisions	169.5	145
Mexican tax on consolidated dividends		9
Deferred workers participation	37.8	24.7
Accrued salaries, wages and vacations	8.5	10
Sales price adjustment (PUI)	(5.8)	3
Social responsibility expenses	4.3	2.1
Deferred charges	41.8	14.5
Valuation allowance on U.S. deferred tax assets, foreign tax credits and U.S. tax effect on Peruvian deferred	(1,343.2)	(1,097)
Other	19.5	9.9
Total deferred tax assets	93.1	54
Liabilities:
Property, plant and equipment	(17.2)	(45.4)
Other	(5.3)	(3)
Total deferred tax liabilities	(22.5)	(48.4)
Total net deferred tax assets	70.6	$ 5.6
Increase in valuation allowance	$ 246.2
U.S. statutory rate (as a percent)	21.00%	21.00%	21.00%	35.00%

INCOME TAXES_ - Carryforward (D

INCOME TAXES: - Carryforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Foreign tax credits
Other U.S. tax credits	$ 0
Unrecognized Tax Benefits	$ 66.1	$ 58.4	$ 214.5
Income Tax Rate (as a percent)	21.00%	21.00%	21.00%	35.00%
Mexico
Foreign tax credits
Unrecognized Tax Benefits	$ 0
Income Tax Rate (as a percent)	30.00%	30.00%	30.00%
Peru
Foreign tax credits
Income Tax Rate (as a percent)	29.50%	29.50%	29.50%
Foreign
Foreign tax credits
Tax credits carryback period	1 year
Tax credits carryforward period	10 years
Increase in foreign tax credits	$ 15.9
Unrecognized Tax Benefits	66.1
Foreign tax credit carryforward	1,040
Foreign tax credit carryforward net of unrecognized tax benefit	973.9
2023 \| Foreign
Foreign tax credits
Foreign tax credit carryforward	39.4
2024 \| Foreign
Foreign tax credits
Foreign tax credit carryforward	102
2025 \| Foreign
Foreign tax credits
Foreign tax credit carryforward	189.5
2026 \| Foreign
Foreign tax credits
Foreign tax credit carryforward	107
2028 \| Foreign
Foreign tax credits
Foreign tax credit carryforward	159.6
2029 \| Foreign
Foreign tax credits
Foreign tax credit carryforward	204.9
2030 \| Foreign
Foreign tax credits
Foreign tax credit carryforward	$ 237.6

INCOME TAXES_ - Other (Details)

INCOME TAXES: - Other (Details) $ in Millions	12 Months Ended
INCOME TAXES: - Other (Details) $ in Millions	Dec. 31, 2020USD ($)item	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2021USD ($)
Income Taxes
Total cash, cash equivalents and short-term investments	$ 2,594.4
Deferred tax asset	93.1	$ 54
State income tax liability	0
Withholding taxes due to the tax treaty between the United States and Mexico	0
Changes in unrecognized tax benefits
Unrecognized tax benefits, opening balance	58.4	214.5
Gross increases - tax positions in prior period		7.5
Gross increases - current-period tax positions	7.7
Gross decreases - current-period tax positions		(4.2)
Decreases related to settlements with taxing authorities		144.4
Increase (decrease) in unrecognized tax benefits	7.7	(156.1)
Unrecognized tax benefits, ending balance	66.1	58.4	$ 214.5
Amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate	$ 0
Number of major tax jurisdictions \| item	3
Income tax expected to be paid				$ 0.6
Foreign subsidiaries
Income Taxes
Total cash, cash equivalents and short-term investments	$ 1,297.3
Deferred tax asset	200
Foreign
Changes in unrecognized tax benefits
Unrecognized tax benefits, ending balance	$ 66.1
Peru
Income Taxes
Royalty charge assessed as a percentage of net sales	1.00%
Royalty charges	$ 60.6	42.3	32.9
Provision for royalty tax	31.4	14.2	9
Peruvian special mining tax	$ 50	38.1	30.6
Changes in unrecognized tax benefits
Accrued interest and penalties included in liability for uncertain tax positions		$ 10.5	$ 1.9
Peru \| Minimum
Income Taxes
Mining royalty tax (as a percent)	1.00%
Special mine tax (as a percent)	2.00%
Peru \| Maximum
Income Taxes
Mining royalty tax (as a percent)	12.00%
Special mine tax (as a percent)	8.40%
Mexico
Income Taxes
Mining royalty tax (as a percent)	7.50%
Mining royalty amount on earnings before taxes	$ 60.1
Additional royalty tax over gross income from sales of gold, silver and platinum (as a percent)	0.50%
Additional royalty over sales revenue from gold, silver and platinum	$ 0.9
Changes in unrecognized tax benefits
Unrecognized tax benefits, ending balance	0
United States
Changes in unrecognized tax benefits
Accrued interest and penalties included in liability for uncertain tax positions	$ 0

WORKERS' PARTICIPATION_ (Detail

WORKERS' PARTICIPATION: (Details) $ in Millions	12 Months Ended
WORKERS' PARTICIPATION: (Details) $ in Millions	Dec. 31, 2020USD ($)item	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Statutory workers' participation
Current	$ 248.5	$ 188.8	$ 219.9
Deferred	19.8	29.8	9.8
Workers' participation expense (in USD)	$ 268.3	$ 218.6	$ 229.7
Peru
Statutory workers' participation
Provision for workers' participation as a percentage of pre-tax earnings	8.00%
Number of months for which an individual worker's salary is capped for consideration of annual individual worker participation	18 months
Maximum taxable units contributed by employer to benefit fund (in Peruvian taxable units) \| item	2,200
Maximum employer contribution to benefit fund (in USD)	$ 2.6
Mexico
Statutory workers' participation
Provision for workers' participation as a percentage of pre-tax earnings	10.00%

LEASES_ (Details)

LEASES: (Details) - USD ($) $ in Millions	12 Months Ended
LEASES: (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Leases
Lessee, operating lease, option to extend	false
Lessee, operating lease, option to terminate	false
The weighted average remaining lease term	9 years
The weighted average discount rate	3.71%
Total lease expense	$ 114.8	$ 114.8
Short term lease costs	0.1
Maturities of lease liabilities
2021	114.7
2022	113.7
2023	112.3
2024	104.7
2025	103.7
After 2025	723
Total lease payments	1,272.1
Less: interest on lease liabilities	(293.1)
Lease liabilities	979
Cost of sales (exclusive of depreciation, amortization and depletion)
Leases
Total lease expense	114.4	114.4
Selling, general and administrative
Leases
Total lease expense	0.2	0.2
Exploration
Leases
Total lease expense	$ 0.2	$ 0.2
Minimum
Leases
Remaining lease terms	2 years
Maximum
Leases
Remaining lease terms	13 years

ASSET RETIREMENT OBLIGATION_ (D

ASSET RETIREMENT OBLIGATION: (Details) $ in Millions	Jun. 24, 2019	Dec. 31, 2020USD ($)item	Dec. 31, 2019USD ($)
ASSET RETIREMENT OBLIGATION:
Maximum annual guarantees secured	50.00%
Percentage of guarantee for Lima complex		50.00%
Percentage of security for LOC		50.00%
Total guarantees		$ 56.5
Asset retirement obligation activity
Balance at the beginning of the year		262.3	$ 217.7
Changes in estimates		269.3	36.4
Closure Payments		(1.2)	(5.3)
Accretion expense		14.6	13.5
Balance at the end of the year		$ 545	$ 262.3
Peru
ASSET RETIREMENT OBLIGATION:
Period after which successive reviews are required by the law (in years)		5 years
Number of units with future closure costs recognized as an asset retirement obligation \| item		3
Asset retirement obligation activity
Changes in estimates		$ 28.1
Mexico
Asset retirement obligation activity
Changes in estimates		$ 269.3

FINANCING_ (Details)

FINANCING: (Details) $ in Millions	Apr. 20, 2015USD ($)tranche	Dec. 31, 2020USD ($)itemgrade	Nov. 30, 2012USD ($)item	Dec. 31, 2019USD ($)	Sep. 26, 2019USD ($)
FINANCING
Face amount		$ 6,651.2	$ 4,200	$ 7,051
Debt discount		67.6		69.6
Issuance costs	$ (11.8)	(39.4)		(40.8)
Long-term debt, Carrying Value		6,544.2		6,940.8
Less, current portion				399.8
Long-term debt, net of current portion		$ 6,544.2		6,541
Number of tranches \| tranche	2
Underwriters discount	$ 20.2
Number of times for which senior unsecured notes were issued \| item			6
Percentage of principal amount at which notes may be required to be repurchased in event of change of control in the entity		101.00%
Minimum
FINANCING
Number of decreased gradations that could cause a change of control triggering event \| grade		1
5.375% Senior unsecured notes due 2020
FINANCING
Face amount				400
Debt discount				0.1
Issuance costs				(0.1)
Long-term debt, Carrying Value				$ 399.8
Interest rate (as a percent)				5.375%
3.500% Senior unsecured notes due 2022
FINANCING
Face amount		$ 300		$ 300
Debt discount		0.2		0.3
Issuance costs		(0.3)		(0.5)
Long-term debt, Carrying Value		$ 299.5		$ 299.2
Interest rate (as a percent)		3.50%		3.50%
3.875% Senior unsecured notes due 2025
FINANCING
Face amount	$ 500	$ 500		$ 500
Debt discount		1.3		1.6
Issuance costs		(1.2)		(1.5)
Long-term debt, Carrying Value		$ 497.5		$ 496.9
Interest rate (as a percent)	3.875%	3.875%		3.875%
9.250% Yankee Bonds due 2028
FINANCING
Face amount		$ 51.2		$ 51
Long-term debt, Carrying Value		$ 51.2		$ 51.2
Interest rate (as a percent)		9.25%		9.25%
9.250% Yankee Bonds due 2028 \| Minera Mexico \| Minimum
FINANCING
Ratio of EBITDA to interest expense \| item		2.5
7.500% Senior unsecured notes due 2035
FINANCING
Face amount		$ 1,000		$ 1,000
Debt discount		12		12.4
Issuance costs		(8)		(8.3)
Long-term debt, Carrying Value		$ 980		$ 979.3
Interest rate (as a percent)		7.50%		7.50%
6.750% Senior unsecured notes due 2040
FINANCING
Face amount		$ 1,100		$ 1,100
Debt discount		6.9		7.1
Issuance costs		(5.6)		(5.7)
Long-term debt, Carrying Value		$ 1,087.5		$ 1,087.2
Interest rate (as a percent)		6.75%		6.75%
5.250% Senior unsecured notes due 2042
FINANCING
Face amount		$ 1,200		$ 1,200
Debt discount		18.6		19
Issuance costs		(6.2)		(6.3)
Long-term debt, Carrying Value		$ 1,175.2		$ 1,174.7
Interest rate (as a percent)		5.25%		5.25%
5.875% Senior unsecured notes due 2045
FINANCING
Face amount	$ 1,500	$ 1,500		$ 1,500
Debt discount		16.1		16.4
Issuance costs		(8.5)		(8.6)
Long-term debt, Carrying Value		$ 1,475.4		$ 1,475
Interest rate (as a percent)	5.875%	5.875%		5.875%
Fixed-rate senior unsecured notes issued in April 2015
FINANCING
Face amount	$ 2,000
4.500% Minera Mexico Senior unsecured notes due 2050
FINANCING
Face amount		$ 1,000		$ 1,000
Debt discount		12.5		12.7
Issuance costs		(9.6)		(9.8)
Long-term debt, Carrying Value		$ 977.9		$ 977.5
Interest rate (as a percent)		4.50%		4.50%
4.500% Minera Mexico Senior unsecured notes due 2050 \| Minera Mexico S.A. de C.V. Notes
FINANCING
Face amount					$ 1,000
Debt discount					12.7
Issuance costs					$ (9.8)
Interest rate (as a percent)					4.50%

FINANCING_ - Outstanding borrow

FINANCING: - Outstanding borrowing (Details) $ in Millions	Dec. 31, 2020USD ($)
Aggregate maturities of the outstanding borrowings
2022	$ 300
2025	500
Thereafter	5,851.2
Total	6,651.2
Debt discount valuation account	$ 107

BENEFIT PLANS_ - Other (Details

BENEFIT PLANS: - Other (Details) $ in Millions	12 Months Ended
BENEFIT PLANS: - Other (Details) $ in Millions	Dec. 31, 2020USD ($)plan	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Benefit plans
Number of noncontributory defined benefit pension plans \| plan	2
Post retirement defined benefit plans and defined contribution plan
Defined benefit plan, net periodic benefit costs
Service cost	$ 1.4	$ 1.1	$ 1
Interest cost	1.7	1.8	1.6
Expected return on plan assets	(2.9)	(3.5)	(3.4)
Amortization of net actuarial loss	0.1
Amortization of prior service cost (credit)	0.2	0.2	0.2
Settlement / Curtailment	(0.4)		(0.2)
Amortization of net loss (gain)	0.2	0.3	0.2
Net periodic benefit cost	0.3	(0.1)	(0.6)
Change in benefit obligation:
Projected benefit obligation at beginning of year	33.7	27.4
Service cost	1.4	1.1	1
Interest cost	1.7	1.8	1.6
Benefits paid	(1.9)	(1.8)
Actuarial (gain)/loss	(4.2)	3.6
Actuarial gain assumption changes	0.8	0.9
Inflation adjustment	(1.6)	0.7
Projected benefit obligation at end of year	29.9	33.7	27.4
Change in plan assets:
Fair value of plan assets at beginning of year	51.6	46.7
Actual return on plan assets	6.5	4.8
Employer contributions	(0.6)	(0.6)
Benefits paid	(0.9)	(0.9)
Currency exchange rate adjustment	(2.2)	1.6
Fair value of plan assets at end of year	54.4	51.6	46.7
Funded status at end of year				$ 24.5	$ 17.9
Amounts recognized in statement of financial position
Non-current assets				24.5	17.9
Total				24.5	17.9
Amounts recognized in accumulated other comprehensive income
Net loss (gain)				3	7.6
Prior service cost (credit)				1.2	1.4
Total, net of tax	9	7.2	7.2	4.2	9
Net loss (gain), income taxes				(2.3)	(5.4)
Reconciliation of accumulated other comprehensive income:
Accumulated other comprehensive income at beginning of plan year	9	7.2
Net loss/(gain) amortized during the year	(4.1)	1.9
Net loss/(gain) occurring during the year	(0.3)	(0.2)
Currency exchange rate adjustment	(0.4)	0.1
Net adjustment to accumulated other comprehensive income	(4.8)	1.8
Accumulated other comprehensive income at end of plan year	4.2	9	$ 7.2
Net adjustment to accumulated other comprehensive income, income taxes	3.1	(2.2)
Amounts in accumulated other comprehensive income amortized and recognized as a component of net periodic benefit cost, net of income tax
Net loss / (gain)	(4.1)	1.8
Amortization of net (loss) gain	(0.3)	(0.2)
Total amortization expenses	$ (4.4)	$ 1.6
Expected Benefit Payments
2021				3.1
2022				1.7
2023				1.8
2024				2
2025				1.8
2026 to 2028				12.5
Total				22.9
Post retirement defined benefit plans and defined contribution plan \| Expatriate Plan
Assumptions used to determine the pension obligation and other post-retirement benefits and cost
Discount rate (as a percent)	1.90%	2.85%	3.90%
Expected long-term rate of return on plan asset (as a percent)	3.50%	4.00%	4.00%
Post retirement defined benefit plans and defined contribution plan \| Mexican Health Plan
Assumptions used to determine the pension obligation and other post-retirement benefits and cost
Discount rate (as a percent)	7.43%	7.15%	8.45%
Expected long-term rate of return on plan asset (as a percent)	7.43%	7.15%	8.45%
Rate of increase in future compensation level (as a percent)	4.50%	4.50%	4.50%
Post-retirement Health care plans
Defined benefit plan, net periodic benefit costs
Interest cost	$ 1.3	$ 0.9	$ 0.9
Amortization of prior service cost (credit)		(0.2)	(0.2)
Net periodic benefit cost	1.3	0.7	0.7
Change in benefit obligation:
Projected benefit obligation at beginning of year	20.6	11.9
Interest cost	1.3	0.9	0.9
Benefits paid	(1.5)	(1.3)
Actuarial (gain)/loss	4.5	8.6
Inflation adjustment	(1.1)	0.5
Projected benefit obligation at end of year	23.8	20.6	11.9
Change in plan assets:
Employer contributions	(0.1)	(0.1)
Benefits paid	(0.1)	(0.1)
Funded status at end of year				23.8	20.6
Amounts recognized in statement of financial position
Current liabilities					(0.1)
Non-current liabilities				(23.8)	(20.5)
Total				(23.8)	(20.6)
Amounts recognized in accumulated other comprehensive income
Net loss (gain)				4.6	1.5
Total, net of tax	1.5	(4.4)	(4.4)	4.6	1.5
Net loss (gain), income taxes				(1.9)	$ (0.7)
Reconciliation of accumulated other comprehensive income:
Accumulated other comprehensive income at beginning of plan year	1.5	(4.4)
Net loss/(gain) amortized during the year		0.1
Net loss/(gain) occurring during the year	3.2	6
Currency exchange rate adjustment	(0.1)	(0.2)
Net adjustment to accumulated other comprehensive income	3.1	5.9
Accumulated other comprehensive income at end of plan year	4.6	1.5	$ (4.4)
Net adjustment to accumulated other comprehensive income, income taxes	(1.2)	(2.6)
Amounts in accumulated other comprehensive income amortized and recognized as a component of net periodic benefit cost, net of income tax
Net loss / (gain)	3.2	5.9
Amortization of net (loss) gain		0.2
Total amortization expenses	$ 3.2	$ 6.1
Expected Benefit Payments
2021				1.5
2022				1.6
2023				1.5
2024				1.5
2025				1.6
2026 to 2030				8.6
Total				$ 16.3
Post-retirement Health care plans \| Expatriate Plan
Assumptions used to determine the pension obligation and other post-retirement benefits and cost
Discount rate (as a percent)	1.90%	2.85%	3.90%
Expected Benefit Payments
Assumed trend rate for covered health care benefit cost (as a percent)	5.10%
Assumed trend rate for covered health care benefit cost post-65 years of age (as a percent)	4.90%
Assumed ultimate trend rate for health care benefit cost (as a percent)				4.20%
Assumed ultimate trend rate for health care benefit cost post-65 years of age (as a percent)	4.00%
Post-retirement Health care plans \| Mexican Health Plan
Expected Benefit Payments
Assumed trend rate for covered health care benefit cost (as a percent)		4.50%
Effect of one percentage-point change in assumed other benefit cost trend rates
Effect of one percentage-point increase on total service and interest cost components	$ 1.9
Effect of one percentage-point decrease on total service and interest cost components	1.5
Effect of one percentage-point increase on post-retirement benefit obligation	24.7
Effect of one percentage-point decrease on post-retirement benefit obligation	$ 22.2
Post-retirement Health care plans \| Weighted average \| Mexican Health Plan
Assumptions used to determine the pension obligation and other post-retirement benefits and cost
Discount rate (as a percent)	7.43%	7.15%	8.45%

BENEFIT PLANS_ - Post retiremen

BENEFIT PLANS: - Post retirement (Details) - Post retirement defined benefit plans and defined contribution plan - Mexican Health Plan $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)entity	Dec. 31, 2019
Assumptions used to determine the pension obligation and other post-retirement benefits and cost
Number of financial institutions managing plan assets \| entity	3
Plan obligations as a percentage of benefit obligation	100.00%
Asset allocation (as a percent)	100.00%	100.00%
Expected employer contribution in next fiscal year \| $	$ 2.3
Parent Company (Grupo Mexico) common shares
Assumptions used to determine the pension obligation and other post-retirement benefits and cost
Asset allocation (as a percent)	22.00%
Treasury bills
Assumptions used to determine the pension obligation and other post-retirement benefits and cost
Asset allocation (as a percent)	78.00%	80.00%
Equity securities
Assumptions used to determine the pension obligation and other post-retirement benefits and cost
Asset allocation (as a percent)	22.00%	20.00%

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES: - Environmental matters (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2011personcategory
Environmental costs
Environmental capital investment	$ 37.8	$ 82.9	$ 102.8
Peru
Environmental costs
Environmental capital investment		18.6	59.3
Environmental capital investment	(3.3)
Mexico
Environmental costs
Environmental capital investment	$ 41.1	$ 64.3	$ 43.5
Number of categories of collective actions \| category				3
Minimum number of people claiming injury due to collective action initiative in Civil Federal Procedures Code (CFPC) \| person				30

COMMITMENTS AND CONTINGENCIES_3

COMMITMENTS AND CONTINGENCIES: - Guaymas sulfuric acid spill (Details) - Marine Terminal in Guaymas	Jul. 19, 2019item	Jul. 09, 2019m³
Volume of sulfuric acid discharged in the incident at Guaymas		3
Water volume at Guaymas bay		340,000,000
Number of times of renewal \| item	4
Number of years of each renewal	2 years

COMMITMENTS AND CONTINGENCIES_4

COMMITMENTS AND CONTINGENCIES: - Litigation matters (Details)	3 Months Ended	6 Months Ended	12 Months Ended
	Sep. 30, 2016lawsuit	Jun. 30, 2015lawsuititem	Dec. 31, 2020claimitemlawsuit	Dec. 31, 2015itemlawsuit	Dec. 31, 2019item	Dec. 31, 2018lawsuit
Litigation Matter
Number of collective action lawsuits		6
Number of subsidiaries against which lawsuits were filed \| item		2
Number of collective action lawsuits dismissed		2
Number of lawsuits in process			4
Number of civil actions seeking damages						33
Number Of Constitutional Action Lawsuits				4
Number of subsidiaries to which environmental impact authorizations were granted \| item				1
Tia Maria
Litigation Matter
Number of lawsuits			5
Buenavista del Cobre, S.A. de C.V
Litigation Matter
Number of civil actions seeking damages				8	3	3
Number of resolutions \| claim			45
Francisca Garcia Enriquez
Litigation Matter
Number of additional constitutional lawsuits filed				2
Mario Alberto Salcido et al; Maria Elena Heredia Bustamante et al; Martin Eligio Ortiz Gamez et al and Maria de los Angeles Enriquez Bacame et al
Litigation Matter
Number of additional constitutional lawsuits filed	4
Mario Alberto Salcido et al; Maria Elena Heredia Bustamante et al; Martin Eligio Ortiz Gamez et al and Maria de los Angeles Enriquez Bacame et al \| Mexico
Litigation Matter
Number of monitoring wells downstream from the dam \| item			3
Period to submit Semarnat			2 years
Norberto Bustamante et al
Litigation Matter
Number of additional constitutional lawsuits filed			2
Acciones Colectivas de Sinaloa
Litigation Matter
Number of lawsuits in process			3

COMMITMENTS AND CONTINGENCIES_5

COMMITMENTS AND CONTINGENCIES: - Labor matters (Details)

1 Months Ended

12 Months Ended

Nov. 30, 2019PEN (S/)

Nov. 30, 2019USD ($)

May 31, 2019PEN (S/)

May 31, 2019USD ($)

Mar. 31, 2019PEN (S/)item

Mar. 31, 2019USD ($)item

Aug. 31, 2018PEN (S/)item

Aug. 31, 2018USD ($)item

Jun. 30, 2018PEN (S/)

Jun. 30, 2018USD ($)

Dec. 31, 2020USD ($)itememployee

Aug. 22, 2018USD ($)

Labor Matters

Labor matters

Annual salary increase (as a percent)

5.00%

5.50%

Labor Matters | Year One Collective Bargaining Agreement

Labor matters

Term of agreement

1 year

Labor expense

$ 13,300

S/ 16,000

$ 4,800

Labor Matters | Year Three Collective Bargaining Agreement

Labor matters

Term of agreement

3 years

Labor expense | S/

S/ 45,000

Peru | Labor Matters

Labor matters

Percentage of labor unionized

66.00%

Total number of workers | employee

4,739

Number of labor unions

Number of labor unions represent majority of workers

Number of labor unions other than majority workers unions

Term of agreement

3 years

Annual salary increase (as a percent)

5.00%

Labor expense

S/ 45,000

$ 13,600

S/ 45,000

$ 13,600

S/ 45,000

$ 13,600

Number of additional unions

Mexico | San Martin

Labor matters

Budgeted cost for rehabilitation of mine | $

$ 97,700,000

Total expense incurred on rehabilitation of mine till date | $

$ 86,400,000

COMMITMENTS AND CONTINGENCIES_6

COMMITMENTS AND CONTINGENCIES: - Other (Details) S/ in Millions, $ in Millions	Feb. 20, 2020MW	Jul. 15, 2019complaint	Jun. 30, 2018USD ($)T	May 31, 2016MW	Jul. 31, 2014MW	Jun. 30, 2014MW	Dec. 31, 2020USD ($)itemT	Dec. 31, 2020PEN (S/)itemT
Other commitments
Commitment for capital projects \| $							$ 365.8
Tia Maria \| Peru
Other commitments
Project budget \| $							1,400
Amount spend as of the current date \| $							$ 338.8
Annual production ( in tons) \| T							120,000	120,000
Number Of Complaints \| complaint		3
Number of jobs expected to be generated \| item							9,000	9,000
Number of direct jobs expected to be generated \| item							3,600	3,600
Number of indirect jobs expected to be generated \| item							5,400	5,400
Number of workers expected to be directly employed \| item							600	600
Number of workers expected to be indirectly employed \| item							4,200	4,200
Toquepala Concentrator Expansion \| Peru
Other commitments
Amount committed to funding for social and infrastructure improvement projects							$ 122.8	S/ 445.0
Commitment liability recorded in the balance sheet \| $							41.3
Development Fund Moquegua Region \| Peru
Other commitments
Amount committed to funding for social and infrastructure improvement projects							275.9	1,000
Copper \| Michiquillay \| Peru
Other commitments
Annual production ( in tons) \| T			225,000
Contingent contractual obligation \| $			$ 400
Estimated mineralized material (in tons) \| T			1,150,000,000
Copper grade percentage			0.63%
Initial mine life			25 years
Contractual obligation paid on project \| $			$ 12.5
Remaining amount to pay if project is developed \| $			$ 387.5
Power purchase agreements \| Electroperu S.A \| Peru
Other commitments
Purchase agreement, contracted power capacity (in megawatts) \| MW						120
Term of power purchase agreement related to sale of power plant						20 years
Power purchase agreements \| Kallpa \| Peru
Other commitments
Purchase agreement, contracted power capacity (in megawatts) \| MW					120
Term of power purchase agreement related to sale of power plant				10 years	10 years
Power purchase agreements \| Kallpa \| Peru \| Maximum
Other commitments
Purchase agreement, contracted power capacity (in megawatts) \| MW				80
Power purchase agreements \| Parque Eolico de Fenicias, S. de R.L. de C.V \| Mexico
Other commitments
Purchase agreement, contracted power capacity (in megawatts) \| MW	611,400
Term of power purchase agreement related to sale of power plant	20 years
Educational Project \| Development Fund Moquegua Region \| Peru
Other commitments
Amount committed to funding for social and infrastructure improvement projects							29.9	108.4
Water Treatment \| Development Fund Moquegua Region \| Peru
Other commitments
Amount committed to funding for social and infrastructure improvement projects							21.5	78
Social Investment For Taxes \| Development Fund Moquegua Region \| Peru
Other commitments
Amount committed to funding for social and infrastructure improvement projects							$ 24	S/ 86.9
Number of infrastructure projects agreed for construction \| item							2	2
Social Investment For Taxes \| Tacna region [Member] \| Peru
Other commitments
Amount committed to funding for social and infrastructure improvement projects							$ 19.2	S/ 69.7
Number of infrastructure projects agreed for construction \| item							1	1

STOCKHOLDERS' EQUITY - Treasury

STOCKHOLDERS' EQUITY - Treasury Stock (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Activity in treasury stock
Balance at the beginning of the period	$ 3,048.9
Purchase of shares	2,900
Balance at the end of the period	$ 3,063.5	$ 3,048.9
Southern Copper common shares
Activity in treasury stock
Treasury stock balance at the end of the period (in shares)	111,522,817	111,537,217
TREASURY STOCK: \| Southern Copper common shares
Activity in treasury stock
Balance at the beginning of the period	$ 2,767.9	$ 2,768.3
Used for corporate purposes	(0.4)	(0.4)	$ (0.4)
Balance at the end of the period	2,767.5	2,767.9	2,768.3
TREASURY STOCK: \| Parent Company (Grupo Mexico) common shares
Activity in treasury stock
Balance at the beginning of the period	281	251.3
Other activity, including dividend, interest and foreign currency transaction effect	15	29.7	18.9
Balance at the end of the period	$ 296	$ 281	$ 251.3

STOCKHOLDERS' EQUITY - Repurcha

STOCKHOLDERS' EQUITY - Repurchase Program (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2008
SCC share repurchase program:
Amount authorized for share repurchase program	$ 3,000	$ 500
Total Number of Shares Purchased	119.5
Cost of purchase of shares	$ 2,900
Closing price of NYSE (in dollars per share)	$ 65.12
Maximum Number of Shares that May Yet Be Purchased Under the Plan @ $39.68	1.3
Percentage of Ownership by Parent	88.90%

STOCKHOLDERS' EQUITY_ - Directo

STOCKHOLDERS' EQUITY: - Directors' Stock Award Plan (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Parent Company (Grupo Mexico) common shares
Activity in directors' stock award plan
Treasury stock balance at the end of the period (in shares)	87,598,097	93,082,532
Directors' Stock Award Plan
Share based Compensation Plan
Common shares received on election as director	1,200
Additional shares issued at each annual general meeting	1,200
Total SCC shares reserved for the plan	600,000	600,000
Period of extension of plan	5 years
Increased share awards issued to directors	1,600
Activity in directors' stock award plan
Total shares granted at the beginning of the period (in shares)	(377,200)	(362,800)
Granted in the period	(14,400)	(14,400)
Total shares granted at the end of the period (in shares)	(391,600)	(377,200)
Remaining shares reserved	208,400	222,800
Share based compensation
Stock based compensation expense	$ 0.4	$ 0.4

STOCKHOLDERS' EQUITY - Compensa

STOCKHOLDERS' EQUITY - Compensation Plan (Details) $ / shares in Units, $ in Millions	Feb. 21, 2019USD ($)$ / shares	Nov. 30, 2018$ / shares	Nov. 30, 2018$ / shares	Jan. 31, 2015$ / shares	Jan. 31, 2015$ / shares	Dec. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares
Grupo Mexico and Americas Mining
Retained earnings
Dividend per share \| $ / shares	$ 0.44428
Settlement dividend paid \| $	$ 36.5
Legal fees paid \| $	$ 13.5
Peruvian Operations
Non-controlling interest
Investment shareholders' interest in Peruvian Branch (as a percent)						0.71%
Employee Stock Purchase 2015 Plan
Information related to compensation cost
Purchase price for initial subscription (in dollars per share) \| (per share)				$ 1.86	$ 38.44	$ 1.86
Percentage of title acquired by employee in every two years on shares paid in previous two years						50.00%
Period of plan						8 years
Ratio of bonus shares granted to participant						0.1
Stock based compensation expense \| $						$ 0.6	$ 0.6	$ 0.6
Unrecognized compensation expense \| $						$ 1.4	$ 2	$ 2.6
Stock award activity, Shares
Outstanding shares at the beginning of the period \| shares						1,379,734	1,840,336
Exercised (in shares) \| shares						(115,324)	(460,602)
Outstanding shares at the end of the period \| shares						1,264,410	1,379,734	1,840,336
Unit Weighted Average Grant Date Fair Value
Outstanding shares at the beginning of the period (in dollars per share) \| $ / shares						$ 2.63	$ 2.63
Exercised (in dollars per share) \| $ / shares						2.63	2.63
Outstanding shares at the end of the period (in dollars per share) \| $ / shares						$ 2.63	$ 2.63	$ 2.63
Employee Stock Purchase 2018 Plan
Information related to compensation cost
Purchase price for initial subscription (in dollars per share) \| (per share)		$ 1.86	$ 37.89
Percentage of title acquired by employee in every two years on shares paid in previous two years						50.00%
Period of plan						8 years
Ratio of bonus shares granted to participant						0.1
Stock based compensation expense \| $						$ 0.7	$ 0.7
Unrecognized compensation expense \| $						$ 3.8	$ 4.5
Stock award activity, Shares
Outstanding shares at the beginning of the period \| shares						4,002,898	2,782,424
Granted (in shares) \| shares							1,238,169
Exercised (in shares) \| shares						(84,440)	(17,695)
Outstanding shares at the end of the period \| shares						3,918,458	4,002,898	2,782,424
Unit Weighted Average Grant Date Fair Value
Outstanding shares at the beginning of the period (in dollars per share) \| $ / shares						$ 1.86	$ 1.86
Granted (in dollars per share) \| $ / shares							1.86
Exercised (in dollars per share) \| $ / shares						1.86	1.86
Outstanding shares at the end of the period (in dollars per share) \| $ / shares						$ 1.86	$ 1.86	$ 1.86
Directors' Stock Award Plan
Information related to compensation cost
Stock based compensation expense \| $						$ 0.4	$ 0.4
Stock award activity, Shares
Granted (in shares) \| shares						14,400	14,400

FAIR VALUE MEASUREMENT (Details

FAIR VALUE MEASUREMENT (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Liabilities:
Long-term debt, Carrying Value	$ 6,544.2	$ 6,940.8
Long-term debt, Fair Value	9,077.8	8,451.4
Short-term investment:
Trading securities	410.2	80
Available-for-sale:
Available-for-sale debt securities	0.6	0.7
Available-for-sale Securities, Current, Total	0.6	0.7
Quoted prices in active markets for identical assets (Level 1)
Liabilities:
Long-term debt, Carrying Value	6,193.6	6,190.6
Long-term debt, Fair Value	8,692.1	7,675.3
Significant other observable inputs (Level 2)
Liabilities:
Long-term debt, Carrying Value	350.6	750.2
Long-term debt, Fair Value	385.7	776.1
Fair value measurements recurring \| Fair value as of the end of the period
Short-term investment:
Trading securities	410.2	80
Derivative:
Total assets, fair value	1,031.9	534
Fair value measurements recurring \| Fair value as of the end of the period \| Copper
Derivative:
Provisionally priced sales	491.9	326.5
Fair value measurements recurring \| Fair value as of the end of the period \| Molybdenum
Derivative:
Provisionally priced sales	129.2	126.8
Fair value measurements recurring \| Asset backed securities \| Fair value as of the end of the period
Available-for-sale:
Available-for-sale debt securities	0.3	0.4
Fair value measurements recurring \| Mortgage backed securities \| Fair value as of the end of the period
Available-for-sale:
Available-for-sale debt securities	0.3	0.3
Fair value measurements recurring \| Quoted prices in active markets for identical assets (Level 1)
Short-term investment:
Trading securities	410.2	80
Derivative:
Total assets, fair value	1,031.3	533.3
Fair value measurements recurring \| Quoted prices in active markets for identical assets (Level 1) \| Copper
Derivative:
Provisionally priced sales	491.9	326.5
Fair value measurements recurring \| Quoted prices in active markets for identical assets (Level 1) \| Molybdenum
Derivative:
Provisionally priced sales	129.2	126.8
Fair value measurements recurring \| Significant other observable inputs (Level 2)
Available-for-sale:
Available-for-sale Securities, Current, Total	0.6	0.7
Fair value measurements recurring \| Significant other observable inputs (Level 2) \| Asset backed securities
Available-for-sale:
Available-for-sale debt securities	0.3	0.4
Fair value measurements recurring \| Significant other observable inputs (Level 2) \| Mortgage backed securities
Available-for-sale:
Available-for-sale debt securities	$ 0.3	$ 0.3

CONCENTRATION OF RISK_ (Details

CONCENTRATION OF RISK: (Details) $ in Millions	12 Months Ended
CONCENTRATION OF RISK: (Details) $ in Millions	Dec. 31, 2020USD ($)item	Dec. 31, 2019	Dec. 31, 2018
Concentration of risk
Number of open-pit copper mines \| item	4
Number of underground poly metallic mines \| item	5
Number of smelters \| item	2
Number of refineries \| item	10
Total cash and short-term investment	$ 2,594.4
Cash equivalents
Concentration of risk
Total cash and short-term investment	$ 2,594.4
Percentage of total cash	100.00%
Percentage of cash in US dollars	97.00%
Cash equivalents \| United States
Concentration of risk
Total cash and short-term investment	$ 1,968.8
Percentage of total cash	75.90%
Percentage invested in one institution of country	14.10%
Percentage invested in one institution of total cash	10.70%
Cash equivalents \| Switzerland
Concentration of risk
Total cash and short-term investment	$ 340.3
Percentage of total cash	13.10%
Percentage invested in one institution of country	79.40%
Percentage invested in one institution of total cash	10.40%
Cash equivalents \| Peru
Concentration of risk
Total cash and short-term investment	$ 35.5
Percentage of total cash	1.40%
Percentage invested in one institution of country	81.40%
Percentage invested in one institution of total cash	1.10%
Cash equivalents \| Mexico
Concentration of risk
Total cash and short-term investment	$ 249.8
Percentage of total cash	9.60%
Percentage invested in one institution of country	53.80%
Percentage invested in one institution of total cash	5.20%
Accounts receivable trade \| Five largest customers
Concentration of risk
Percentage of accounts receivable and total sales	35.30%	37.60%	34.20%
Accounts receivable trade \| Largest customer
Concentration of risk
Percentage of accounts receivable and total sales	12.90%	13.00%	10.90%
Total sales \| Five largest customers
Concentration of risk
Percentage of accounts receivable and total sales	28.10%	28.00%	28.40%
Total sales \| Largest customer
Concentration of risk
Percentage of accounts receivable and total sales	10.00%	10.40%	9.30%

RELATED PARTY TRANSACTIONS_ (De

RELATED PARTY TRANSACTIONS: (Details) $ in Millions	1 Months Ended		12 Months Ended
RELATED PARTY TRANSACTIONS: (Details) $ in Millions	May 31, 2020USD ($)	Sep. 30, 2019USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2012itemMW	Dec. 31, 2014item
RELATED PARTY TRANSACTIONS:
Related parties receivable current:			$ 23.3	$ 30	$ 101.5
Related parties receivable non-current:				59.5
Related parties payable:			104.3	86.4
Total purchases			4.1	2.9	12.9
Total sales			1.9	2.2	1.5
Minimum
RELATED PARTY TRANSACTIONS:
Aggregate consideration of Material Affiliate Transaction to be be authorized by the General Counsel and CFO			8
Maximum
RELATED PARTY TRANSACTIONS:
Aggregate consideration of Material Affiliate Transaction to be be authorized by the General Counsel and CFO			10
Grupo Mexico and affiliates
RELATED PARTY TRANSACTIONS:
Total purchases			576.3	385.6	380.5
Total sales			132.9	58.9	150.3
Asarco LLC
RELATED PARTY TRANSACTIONS:
Related parties receivable current:			5.3	10.8
Related parties receivable non-current:				59.5
Related parties payable:			13.9	4.3
Total purchases			233.9	37.6	37.2
Total sales			77.9	11.3	81.8
Accounts Receivable		$ 62
Making quarterly payments		$ 0.5
Asarco LLC \| Other Noncurrent Assets [Member]
RELATED PARTY TRANSACTIONS:
Related parties receivable non-current:			2.2	2.3
Asarco LLC \| London Interbank Offered Rate (LIBOR) [Member]
RELATED PARTY TRANSACTIONS:
Debt Instrument, Basis Spread on Variable Rate		2.00%
AMMINCO
RELATED PARTY TRANSACTIONS:
Related parties receivable current:				0.1
Related parties payable:			19.6	16.9
Total purchases			18.6	17.8	8
Total sales			0.1	0.1	0.3
Compania Perforadora Mexico, S.A.P.I. de C.V. and affiliates
RELATED PARTY TRANSACTIONS:
Related parties receivable current:			0.3	0.3
Total sales				0.1
Eolica El Retiro, S.A.P.I. de C.V.
RELATED PARTY TRANSACTIONS:
Related parties payable:			0.3
Total purchases			$ 1	$ 2.9	3.6
Number of wind turbines \| item							37
Percentage of supply to third-party energy users			9.60%	18.20%
Ferrocarril Mexicano, S.A. de C.V.
RELATED PARTY TRANSACTIONS:
Related parties payable:			$ 4.7	$ 6.4
Total purchases			45.8	44.1	41.7
Grupo Mexico
RELATED PARTY TRANSACTIONS:
Related parties receivable current:			2.7	2.7
Related parties payable:			0.9	1.1
Total purchases			10	10	10.1
Donations			7.1	9.6
Mexico Generadora de Energia, S. de R.L. ("MGE")
RELATED PARTY TRANSACTIONS:
Related parties receivable current:			14.4	15.3
Related parties payable:			40.8	40.2
Total purchases			213.3	202.2	200.1
Total sales			$ 54.9	$ 47.4	68.2
Accounts Receivable	$ 97.2
Making quarterly payments	$ 5.1
Debt Instrument, Basis Spread on Variable Rate	8.28%
Mexico Generadora de Energia, S. de R.L. ("MGE") \| Mexico
RELATED PARTY TRANSACTIONS:
Number of natural gas-fired combined cycle power generating units \| item						2
Net total capacity (in megawatts) \| MW						516.2
Percentage of supply to third-party energy users			2.30%	5.20%
Mexico Compania Constructora S.A de C.V.
RELATED PARTY TRANSACTIONS:
Related parties payable:			$ 22.9	$ 16
Total purchases			42.6	60.3	72.9
Mexico Proyectos y Desarrollos, S.A. de C.V. and affiliates ("MPD")
RELATED PARTY TRANSACTIONS:
Related parties receivable current:			0.2	0.2
Related parties payable:			0.7
Total purchases			$ 11.1	10.7	6.9
Apu Coropuna S.R.L.
RELATED PARTY TRANSACTIONS:
Ownership percentage			30.00%
Related to the controlling group
RELATED PARTY TRANSACTIONS:
Total purchases			$ 0.2	0.2	0.2
Boutique Bowling de Mexico, S.A. de C.V.
RELATED PARTY TRANSACTIONS:
Related parties receivable current:			0.2	0.1
Related parties payable:			0.3	0.2
Total purchases			0.4	0.4	0.3
Total sales			0.1	0.1	0.2
Empresarios Industriales de Mexico, S.A. de C.V
RELATED PARTY TRANSACTIONS:
Total sales				0.2
Mexico Transportes Aereos, S.A. de C.V. ("Mextransport")
RELATED PARTY TRANSACTIONS:
Related parties receivable current:				0.4
Related parties payable:			0.1	1.2
Total sales			1.7	1.8	1.2
Operadora de Cinemas S.A. de C.V.
RELATED PARTY TRANSACTIONS:
Related parties receivable current:			0.2	0.1
Related parties payable:			0.1	0.1
Total purchases			3.5	2.3	12.4
Total sales			$ 0.1	$ 0.1	$ 0.1
Equity investment in affiliate
RELATED PARTY TRANSACTIONS:
Ownership percentage			44.20%

SEGMENT AND RELATED INFORMATI_3

SEGMENT AND RELATED INFORMATION: - Financial (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)itemcountrysegment	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Financial information related to segments
Number of reportable segments \| segment	3
Number of countries having open-pit operations \| country	2
Financial information relating to segments
Net sales (including sales to related parties, see note 17)	$ 7,984,900	$ 7,285,600	$ 7,096,700
Cost of sales (exclusive of depreciation, amortization and depletion)	3,929,800	3,606,400	3,409,000
Selling, general and administrative	126,200	131,800	102,600
Depreciation, amortization and depletion	775,600	764,400	674,300
Exploration	32,600	30,000	29,600
Operating income	3,120,700	2,753,000	2,881,200
Interest, net	(347,400)	(319,500)	(261,100)
Other income (expense)	(27,500)	(7,000)	(30,700)
Income taxes	(1,174,400)	(945,300)	(1,053,500)
Equity earnings of affiliate, net of income tax	6,400	10,700	12,300
Non-controlling interest	(7,400)	(6,100)	(5,200)
Net income attributable to SCC	1,570,400	1,485,800	1,543,000
Capital investment	592,200	707,500	1,121,400
Property and mine development, net	9,458,700	9,371,000	9,403,800
Total assets	16,946,500	16,407,400	14,287,600
Intersegment sales
Financial information relating to segments
Net sales (including sales to related parties, see note 17)	(111,000)	(83,200)	(79,300)
Corporate, other and eliminations
Financial information relating to segments
Net sales (including sales to related parties, see note 17)	(111,000)	(83,200)	(79,300)
Cost of sales (exclusive of depreciation, amortization and depletion)	(124,300)	(89,100)	(88,600)
Selling, general and administrative	8,600	6,800	2,100
Depreciation, amortization and depletion	37,700	32,100	28,900
Exploration	12,100	2,700	3,800
Operating income	(45,100)	(35,700)	(25,500)
Capital investment	8,000	6,800	20,600
Property and mine development, net	704,900	346,200	374,500
Total assets	$ 3,573,300	2,470,000	379,100
Mexican Open-pit
Financial information related to segments
Number of open-pit copper mines \| item	2
Financial information relating to segments
Net sales (including sales to related parties, see note 17)	$ 4,412,400	3,963,900	4,075,900
Mexican Open-pit \| Operating segment
Financial information relating to segments
Net sales (including sales to related parties, see note 17)	4,412,400	3,963,900	4,075,900
Cost of sales (exclusive of depreciation, amortization and depletion)	1,991,600	1,613,100	1,611,000
Selling, general and administrative	70,500	78,600	55,300
Depreciation, amortization and depletion	366,700	351,900	360,400
Exploration	2,500	1,800	2,000
Operating income	1,981,100	1,918,500	2,047,200
Capital investment	317,100	244,300	266,800
Property and mine development, net	4,470,500	4,648,500	4,783,800
Total assets	7,236,100	8,081,900	8,165,200
Mexican Open-pit \| Reportable subsegments \| Operating segment
Financial information relating to segments
Net sales (including sales to related parties, see note 17)	$ 4,412,400	3,963,900	4,075,900
Mexican IMMSA Unit
Financial information related to segments
Number of underground poly metal mines \| item	5
Financial information relating to segments
Net sales (including sales to related parties, see note 17)	$ 529,900	464,800	527,900
Mexican IMMSA Unit \| Operating segment
Financial information relating to segments
Net sales (including sales to related parties, see note 17)	529,900	464,800	527,900
Cost of sales (exclusive of depreciation, amortization and depletion)	383,000	380,300	377,200
Selling, general and administrative	9,500	7,900	8,500
Depreciation, amortization and depletion	42,500	52,300	47,600
Exploration	8,600	9,000	5,300
Operating income	86,300	15,300	89,300
Capital investment	72,100	106,300	60,000
Property and mine development, net	548,200	497,100	448,300
Total assets	967,200	837,600	930,200
Mexican IMMSA Unit \| Reportable subsegments \| Operating segment
Financial information relating to segments
Net sales (including sales to related parties, see note 17)	418,900	381,600	448,600
Mexican IMMSA Unit \| Intersegment sales \| Operating segment
Financial information relating to segments
Net sales (including sales to related parties, see note 17)	$ 111,000	83,200	79,300
Peruvian Operations
Financial information related to segments
Number of open-pit copper mines \| item	2
Financial information relating to segments
Net sales (including sales to related parties, see note 17)	$ 3,153,600	2,940,100	2,572,200
Peruvian Operations \| Operating segment
Financial information relating to segments
Net sales (including sales to related parties, see note 17)	3,153,600	2,940,100	2,572,200
Cost of sales (exclusive of depreciation, amortization and depletion)	1,679,500	1,702,100	1,509,400
Selling, general and administrative	37,600	38,500	36,700
Depreciation, amortization and depletion	328,700	328,100	237,400
Exploration	9,400	16,500	18,500
Operating income	1,098,400	854,900	770,200
Capital investment	195,000	350,100	774,000
Property and mine development, net	3,735,100	3,879,200	3,797,200
Total assets	5,169,900	5,017,900	4,813,100
Peruvian Operations \| Reportable subsegments \| Operating segment
Financial information relating to segments
Net sales (including sales to related parties, see note 17)	$ 3,153,600	$ 2,940,100	$ 2,572,200

SEGMENT AND RELATED INFORMATI_4

SEGMENT AND RELATED INFORMATION: - Receivables (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financial information related to segments
Trade receivables	$ 1,068.9	$ 832.9	$ 822.4
Related parties receivable current:	23.3	30	101.5
Related parties receivable non-current:		59.5
Corporate, other and eliminations
Financial information related to segments
Related parties receivable current:	7.1	7.9	19.9
Mexican Open-pit
Financial information related to segments
Trade receivables	566	477.8	505.9
Related parties receivable current:	15.4	22.1	81.6
Related parties receivable non-current:		59.5
Mexican IMMSA Unit
Financial information related to segments
Trade receivables	57.8	38	50.5
Peruvian Operations
Financial information related to segments
Trade receivables	445.1	$ 317.1	$ 266
Related parties receivable current:	$ 0.8

SEGMENT AND RELATED INFORMATI_5

SEGMENT AND RELATED INFORMATION: - Sales (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	$ 7,984.9	$ 7,285.6	$ 7,096.7
Copper
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	6,513.1	5,845.3	5,707.8
Molybdenum
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	510.3	549.4	509.9
Silver
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	249.4	277.8	328.6
Zinc
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	447.8	324.3	300.2
Other
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	264.3	288.8	250.2
Corporate, other and eliminations
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	(111)	(83.2)	(79.3)
Corporate, other and eliminations \| Copper
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	(48.4)	(46.9)	(48.1)
Corporate, other and eliminations \| Silver
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	1.6	(2.3)	(0.1)
Corporate, other and eliminations \| Zinc
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	(55.5)	(29.9)	(28.1)
Corporate, other and eliminations \| Other
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	(8.7)	(4.1)	(3)
Mexican Open-pit
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	4,412.4	3,963.9	4,075.9
Mexican Open-pit \| Operating segment
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	4,412.4	3,963.9	4,075.9
Mexican Open-pit \| Operating segment \| Copper
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	3,762.1	3,314.9	3,459.1
Mexican Open-pit \| Operating segment \| Molybdenum
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	275.2	341	342.5
Mexican Open-pit \| Operating segment \| Zinc
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	235.5	185.9	175.3
Mexican Open-pit \| Operating segment \| Other
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	139.6	122.1	99
Mexican IMMSA Unit
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	529.9	464.8	527.9
Mexican IMMSA Unit \| Operating segment
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	529.9	464.8	527.9
Mexican IMMSA Unit \| Operating segment \| Copper
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	72.1	42	45.6
Mexican IMMSA Unit \| Operating segment \| Silver
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	247.8	280.1	328.7
Mexican IMMSA Unit \| Operating segment \| Zinc
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	155.8	82.7	83.5
Mexican IMMSA Unit \| Operating segment \| Other
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	54.2	60	70.1
Peruvian Operations
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	3,153.6	2,940.1	2,572.2
Peruvian Operations \| Operating segment
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	3,153.6	2,940.1	2,572.2
Peruvian Operations \| Operating segment \| Copper
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	2,727.3	2,535.3	2,251.2
Peruvian Operations \| Operating segment \| Molybdenum
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	235.1	208.4	167.4
Peruvian Operations \| Operating segment \| Zinc
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	112	85.6	69.5
Peruvian Operations \| Operating segment \| Other
SALES VALUE PER SEGMENT:
Net sales (including sales to related parties, see note 17)	$ 79.2	$ 110.8	$ 84.1

SEGMENT AND RELATED INFORMATI_6

SEGMENT AND RELATED INFORMATION: - Geographical (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule of revenue by geographical location
Net sales	$ 7,984.9	$ 7,285.6	$ 7,096.7
Mexico
Schedule of revenue by geographical location
Net sales	1,526.7	1,531.9	1,649.3
United States
Schedule of revenue by geographical location
Net sales	1,363.4	1,195.6	1,258.6
Peru
Schedule of revenue by geographical location
Net sales	335	340	390.4
Brazil
Schedule of revenue by geographical location
Net sales	233	211.7	271.9
Chile
Schedule of revenue by geographical location
Net sales	221.1	191.3	136.3
Other American countries
Schedule of revenue by geographical location
Net sales	42.4	43.1	65.8
Switzerland
Schedule of revenue by geographical location
Net sales	1,443.3	1,173.4	653.4
Italy
Schedule of revenue by geographical location
Net sales	271.6	297	347.3
Spain
Schedule of revenue by geographical location
Net sales	199.4	186.1	169.4
Other European Countries
Schedule of revenue by geographical location
Net sales	521.7	374.6	379.6
Singapore
Schedule of revenue by geographical location
Net sales	863.7	966.9	1,069.2
Japan
Schedule of revenue by geographical location
Net sales	579.5	500.8	483.4
Other Asian countries
Schedule of revenue by geographical location
Net sales	384.1	273.2	222.1
Corporate, other and eliminations
Schedule of revenue by geographical location
Net sales	(111)	(83.2)	(79.3)
Corporate, other and eliminations \| Mexico
Schedule of revenue by geographical location
Net sales	(111)	(83.2)	(79.3)
Mexican Open-pit
Schedule of revenue by geographical location
Net sales	4,412.4	3,963.9	4,075.9
Mexican Open-pit \| Mexico
Schedule of revenue by geographical location
Net sales	1,296.6	1,262.2	1,343
Mexican Open-pit \| United States
Schedule of revenue by geographical location
Net sales	1,182.8	1,054.9	1,008
Mexican Open-pit \| Peru
Schedule of revenue by geographical location
Net sales		1.6
Mexican Open-pit \| Chile
Schedule of revenue by geographical location
Net sales	18.8	1.2
Mexican Open-pit \| Other American countries
Schedule of revenue by geographical location
Net sales	36.8	37.6	60.6
Mexican Open-pit \| Switzerland
Schedule of revenue by geographical location
Net sales	898.2	780.9	453.3
Mexican Open-pit \| Italy
Schedule of revenue by geographical location
Net sales	0.1	45.1	20.6
Mexican Open-pit \| Spain
Schedule of revenue by geographical location
Net sales	199.4	186.1	169.4
Mexican Open-pit \| Other European Countries
Schedule of revenue by geographical location
Net sales	199.9	92.8	234.8
Mexican Open-pit \| Singapore
Schedule of revenue by geographical location
Net sales	319.9	345.4	528.8
Mexican Open-pit \| Japan
Schedule of revenue by geographical location
Net sales	46.9	59.9	71.8
Mexican Open-pit \| Other Asian countries
Schedule of revenue by geographical location
Net sales	213	96.2	185.6
Mexican IMMSA Unit
Schedule of revenue by geographical location
Net sales	529.9	464.8	527.9
Mexican IMMSA Unit \| Mexico
Schedule of revenue by geographical location
Net sales	341.1	352.9	385.6
Mexican IMMSA Unit \| United States
Schedule of revenue by geographical location
Net sales	27.2	6.2	6.6
Mexican IMMSA Unit \| Peru
Schedule of revenue by geographical location
Net sales	13
Mexican IMMSA Unit \| Brazil
Schedule of revenue by geographical location
Net sales	18.7	17.3	43.8
Mexican IMMSA Unit \| Other American countries
Schedule of revenue by geographical location
Net sales	2.9	2.2	3.8
Mexican IMMSA Unit \| Switzerland
Schedule of revenue by geographical location
Net sales	69.9	36.7	43.4
Mexican IMMSA Unit \| Italy
Schedule of revenue by geographical location
Net sales	9.5	13.3	21.7
Mexican IMMSA Unit \| Other European Countries
Schedule of revenue by geographical location
Net sales	40.2	24.9	19.9
Mexican IMMSA Unit \| Singapore
Schedule of revenue by geographical location
Net sales	6.9	10.4	2.2
Mexican IMMSA Unit \| Other Asian countries
Schedule of revenue by geographical location
Net sales	0.5	0.9	0.9
Peruvian Operations
Schedule of revenue by geographical location
Net sales	3,153.6	2,940.1	2,572.2
Peruvian Operations \| United States
Schedule of revenue by geographical location
Net sales	153.4	134.5	244
Peruvian Operations \| Peru
Schedule of revenue by geographical location
Net sales	322	338.4	390.4
Peruvian Operations \| Brazil
Schedule of revenue by geographical location
Net sales	214.3	194.4	228.1
Peruvian Operations \| Chile
Schedule of revenue by geographical location
Net sales	202.3	190.1	136.3
Peruvian Operations \| Other American countries
Schedule of revenue by geographical location
Net sales	2.7	3.3	1.4
Peruvian Operations \| Switzerland
Schedule of revenue by geographical location
Net sales	475.2	355.8	156.7
Peruvian Operations \| Italy
Schedule of revenue by geographical location
Net sales	262	238.6	305
Peruvian Operations \| Other European Countries
Schedule of revenue by geographical location
Net sales	281.6	256.9	124.9
Peruvian Operations \| Singapore
Schedule of revenue by geographical location
Net sales	536.9	611.1	538.2
Peruvian Operations \| Japan
Schedule of revenue by geographical location
Net sales	532.6	440.9	411.6
Peruvian Operations \| Other Asian countries
Schedule of revenue by geographical location
Net sales	$ 170.6	$ 176.1	$ 35.6

SEGMENT AND RELATED INFORMATI_7

SEGMENT AND RELATED INFORMATION: - Provisional Sale (Details) lb in Millions	12 Months Ended
	Dec. 31, 2020USD ($)lb	Dec. 31, 2019USD ($)
Provisionally priced sales:
Provisional price sales adjustment amounts included in net sales	$ (31,500,000)	$ 4,200,000
Copper
Provisionally priced sales:
Provisional price sales adjustment amounts included in accounts receivable	$ (17,400,000)	(4,000,000)
Copper \| January through April 2021
Provisionally priced sales:
Sales volume (in million lbs.) \| lb	139.8
Provisional price	$ 3.52
Molybdenum
Provisionally priced sales:
Provisional price sales adjustment amounts included in accounts receivable	$ (14,100,000)	$ 8,200,000
Molybdenum \| January through March 2021
Provisionally priced sales:
Sales volume (in million lbs.) \| lb	12.9
Provisional price	$ 10.03

SEGMENT AND RELATED INFORMATI_8

SEGMENT AND RELATED INFORMATION: - Long Term Sales Contract (Details)	12 Months Ended
	Dec. 31, 2020T
Copper cathodes \| Mitsui
Long-term sales contract
Term of agreement	3 years
Quantity to be supplied related to additional annual contract from 2016 until 2019 (in tons)	48,000
Molybdenum concentrates \| Molibdenos y Metales
Long-term sales contract
Minimum percentage of total production required to be supplied	70.00%
Molybdenum concentrates \| Molymex
Long-term sales contract
Minimum percentage of total production required to be supplied	80.00%

SUBSEQUENT EVENTS_ (Details)

SUBSEQUENT EVENTS: (Details) - $ / shares	Feb. 24, 2021	Jan. 21, 2021	Feb. 21, 2019
Grupo Mexico and Americas Mining
SUBSEQUENT EVENTS
Dividends declared and paid			$ 0.44428
Subsequent Events
SUBSEQUENT EVENTS
Quarterly dividend authorized (in dollars per share)		$ 0.60
Dividends declared and paid	$ 0.60

Schedule II - Valuation and Q_2

Schedule II - Valuation and Qualifying Accounts and Reserves (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts Receivable
Valuation and Qualifying Accounts and Reserves
Balance at beginning of period	$ 0.5	$ 0.5	$ 1.1
Charged to costs and expenses	8.5
Deductions/Applications	(0.2)		(0.6)
Balance at end of period	8.8	0.5	0.5
Notes issued under par
Valuation and Qualifying Accounts and Reserves
Balance at beginning of period	69.6	58.8	60.5
Charged to costs and expenses	2	1.9	1.7
Additions		12.7
Balance at end of period	67.6	69.6	58.8
Valuation allowance
Valuation and Qualifying Accounts and Reserves
Balance at beginning of period	1,097	819.1	619.6
Charged to costs and expenses	246.2	277.9	199.5
Balance at end of period	$ 1,343.2	$ 1,097	$ 819.1