Southern Copper (SCCO) 10-Q 28 Oct 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Oct. 28, 2019
Document and Entity Information
Entity Registrant Name	SOUTHERN COPPER CORP/
Entity Central Index Key	0001001838
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Document Transition Report	false
Entity File Number	1-14066
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 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
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		773,058,869

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF EARNINGS - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
CONDENSED CONSOLIDATED STATEMENTS OF EARNINGS
Net sales (including sales to related parties, see Note 6)	$ 1,859.5	$ 1,723.7	$ 5,431	$ 5,402.1
Operating cost and expenses:
Cost of sales (exclusive of depreciation, amortization and depletion shown separately below)	906.5	824	2,617.9	2,552.2
Selling, general and administrative	32	26.4	91.4	76.7
Depreciation, amortization and depletion	200.3	170.6	580.6	495.2
Exploration	6.9	6	19.9	20.3
Total operating costs and expenses	1,145.7	1,027	3,309.8	3,144.4
Operating income	713.8	696.7	2,121.2	2,257.7
Interest expense	(90.8)	(90.1)	(271.2)	(270.6)
Capitalized interest	7	20.9	25.6	63.6
Other income (expense)	(6.3)	(7.6)	22	(13.1)
Interest income	5.1	4.4	13.1	9.8
Income before income taxes	628.8	624.3	1,910.7	2,047.4
Income taxes (including royalty taxes, see Note 5)	241	257.9	730	803.6
Net income before equity earnings of affiliate	387.8	366.4	1,180.7	1,243.8
Equity earnings (loss) of affiliate, net of income tax	3.5	4.3	4.2	9.9
Net income	391.3	370.7	1,184.9	1,253.7
Less: Net income attributable to the non-controlling interest	1.7	1.3	4.7	3.9
Net income attributable to SCC	$ 389.6	$ 369.4	$ 1,180.2	$ 1,249.8
Per common share amounts attributable to SCC:
Net earnings-basic and diluted	$ 0.50	$ 0.48	$ 1.53	$ 1.62
Dividends declared and paid	$ 0.40	$ 0.40	$ 1.20	$ 1
Weighted average shares outstanding-basic and diluted	773.1	773	773.1	773

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income and comprehensive income	$ 391.3	$ 370.7	$ 1,184.9	$ 1,253.7
Comprehensive income attributable to the non-controlling interest	1.7	1.3	4.7	3.9
Comprehensive income attributable to SCC	$ 389.6	$ 369.4	$ 1,180.2	$ 1,249.8

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 1,935.2	$ 844.6
Short-term investments	1.7	213.8
Accounts receivable trade	842	822.4
Accounts receivable other (including related parties 2019- $22.3 and 2018 - $101.5)	76.6	150.2
Inventories	1,062.2	1,032.7
Prepaid taxes	211.5	87
Other current assets	48.4	29.3
Total current assets	4,177.6	3,180
Property and mine development, net	9,395.3	9,403.8
Ore stockpiles on leach pads	1,224.9	1,177.4
Intangible assets, net	152	147.7
Related parties receivable	60
Right-of-use assets	1,061.7
Deferred income tax	221	400.9
Equity method investment	107.9	103.6
Other non-current assets	94	71.4
Total assets	16,494.4	14,484.8
Current liabilities:
Current portion of long-term debt	399.7
Accounts payable (including related parties 2019- $77.5 and 2018- $75.3)	575	673.4
Accrued income taxes	80.7	232.8
Accrued workers' participation	141.1	206.7
Accrued interest	133.7	83.9
Lease liabilities current	67.3
Other accrued liabilities	34.7	19.5
Total current liabilities	1,432.2	1,216.3
Long-term debt	6,540.4	5,960.1
Lease liabilities	994.5
Deferred income taxes	205.1	202.6
Non-current taxes payable	62.7	207.1
Other liabilities and reserves	137.6	68.2
Asset retirement obligation	251.6	217.7
Total non-current liabilities	8,191.9	6,655.7
Commitments and contingencies (Note 11)
STOCKHOLDERS' EQUITY (NOTE 12)
Common stock par value $0.01; shares authorized, 2019 and 2018-2,000; shares issued, 2019 and 2018-884.6	8.8	8.8
Additional paid-in capital	3,415.6	3,393.7
Retained earnings	6,439.2	6,186.9
Accumulated other comprehensive income	(2.4)	(2.4)
Treasury stock, at cost, common shares	(3,039.9)	(3,019.6)
Total Southern Copper Corporation stockholders' equity	6,821.3	6,567.4
Non-controlling interest	49	45.4
Total equity	6,870.3	6,612.8
Total liabilities and equity	$ 16,494.4	$ 14,484.8

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Millions, $ in Millions	Sep. 30, 2019	Dec. 31, 2018
CONDENSED CONSOLIDATED BALANCE SHEETS
Accounts receivable other, related parties	$ 22.3	$ 101.5
Accounts payable, related parties	$ 77.5	$ 75.3
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 STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
OPERATING ACTIVITIES
Net income	$ 391.3	$ 370.7	$ 1,184.9	$ 1,253.7
Adjustments to reconcile net earnings to net cash provided from operating activities:
Depreciation, amortization and depletion	200.3	170.6	580.6	495.2
Equity earnings of affiliate, net of dividends received	(3.1)	(3.4)	(2.5)	(3.9)
Loss on foreign currency transaction effect	1	4.8	10.4	31.2
(Benefit) provision for deferred income taxes	(23.8)	(2.2)	26.4	(17.7)
Other, net	3.7	3.5	11.2	(4.4)
Change in operating assets and liabilities:
(Increase) decrease in accounts receivable	(54.9)	34.8	(19.7)	112.3
(Increase) in inventories	(12.7)	(43.6)	(76.9)	(131.2)
Increase (decrease) in accounts payable and accrued liabilities	103.6	175.1	(225)	80.5
(Increase) decrease in other operating assets and liabilities	(20.2)	22.5	(118.9)	(26.8)
Net cash provided by operating activities	585.2	732.8	1,370.5	1,788.9
INVESTING ACTIVITIES
Capital expenditures	(182.7)	(282.3)	(536.1)	(831.8)
Proceeds from sale (purchase) of short-term investments, net	117.1	(185.8)	212	(186)
Other	0.1	0.2	0.2	(12)
Net cash used in investing activities	(65.5)	(467.9)	(323.9)	(1,029.8)
FINANCING ACTIVITIES
Proceeds from issuance of debt	987.3		987.3
Capitalization of debt issuance cost	(9.8)		(9.8)
Cash dividends paid to common stockholders	(309.2)	(309.2)	(927.7)	(773)
Other, net	(0.8)	(0.2)	(0.5)	(1)
Net cash provided by (used in) financing activities	667.5	(309.4)	49.3	(774)
Effect of exchange rate changes on cash and cash equivalents	(4.2)	(20.7)	(5.3)	(22.6)
Increase (decrease) in cash and cash equivalents	1,183	(65.2)	1,090.6	(37.5)
Cash and cash equivalents, at beginning of year	752.2	1,032.5	844.6	1,004.8
Cash and cash equivalents, at end of year	$ 1,935.2	$ 967.3	$ 1,935.2	$ 967.3

CONDENSED CONSOLIDATED STATEM_4

CONDENSED 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 period 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						1,249.8			3.9	1,249.8
Dividends/distributions declared and paid						(773)			(1.2)
Used for corporate purposes			0.4
Other activity, including dividend, interest and foreign currency transaction effect				(17.3)
Other activity of the period		18.5
Balance at end of period at Sep. 30, 2018	$ 8.8	3,391.8	(2,768.3)	(249.7)	$ (3,018)	6,203		6,586.1	44.4	6,630.5
Balance at beginning of period at Jun. 30, 2018		3,382.7	(2,768.3)	(240.8)		6,142.8	0.5	6,525.7	43.4	6,569.1
Increase (Decrease) in Stockholders' Equity
Net earnings						369.4			1.3	369.4
Dividends/distributions declared and paid						(309.2)			(0.3)
Other activity, including dividend, interest and foreign currency transaction effect				(8.9)
Other activity of the period		9.1
Balance at end of period at Sep. 30, 2018	8.8	3,391.8	(2,768.3)	(249.7)	(3,018)	6,203		6,586.1	44.4	6,630.5
Balance at beginning of period at Dec. 31, 2018		3,393.7	(2,768.3)	(251.3)		6,186.9	(2.4)	6,567.4	45.4	6,612.8
Increase (Decrease) in Stockholders' Equity
Net earnings						1,180.2			4.7	1,180.2
Dividends/distributions declared and paid						(927.7)			(1.1)
SCC shareholder derivative lawsuit - received from AMC						36.5
SCC shareholder derivative lawsuit - dividend paid						(36.5)
Used for corporate purposes			0.4
Other activity, including dividend, interest and foreign currency transaction effect				(20.7)
Other activity of the period		21.9				(0.2)
Balance at end of period at Sep. 30, 2019	8.8	3,415.6	(2,767.9)	(272)	(3,039.9)	6,439.2		6,821.3	49	6,870.3
Balance at beginning of period at Jun. 30, 2019		3,407.6	(2,767.9)	(264.5)		6,358.7	$ (2.4)	6,740.3	48.3	6,788.6
Increase (Decrease) in Stockholders' Equity
Net earnings						389.6			1.7	389.6
Dividends/distributions declared and paid						(309.2)			(1)
Other activity, including dividend, interest and foreign currency transaction effect				(7.5)
Other activity of the period		8				0.1
Balance at end of period at Sep. 30, 2019	$ 8.8	$ 3,415.6	$ (2,767.9)	$ (272)	$ (3,039.9)	$ 6,439.2		$ 6,821.3	$ 49	$ 6,870.3

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY
Dividends paid as cash dividend (in dollars per share)	$ 0.40	$ 0.40	$ 1.20	$ 1

DESCRIPTION OF THE BUSINESS_

DESCRIPTION OF THE BUSINESS:	9 Months Ended
	Sep. 30, 2019
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 September 30, 2019, Grupo Mexico through its wholly-owned subsidiary Americas Mining Corporation (“AMC”) owned of the Company’s capital stock. The condensed consolidated financial statements presented herein consist of the accounts of Southern Copper Corporation ("SCC" 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. ​ In the opinion of the Company, the accompanying unaudited condensed consolidated financial statements contain all adjustments (consisting only of normal recurring adjustments) necessary to state fairly the Company’s financial position as of September 30, 2019 and the results of operations, comprehensive income, cash flows and changes in equity for the three and nine months ended September 30, 2019 and 2018. The results of operations for the three and nine months ended September 30, 2019 are not necessarily indicative of the results to be expected for the full year. The December 31, 2018 balance sheet data was derived from audited financial statements, but does not include all disclosures required by generally accepted accounting principles in the United States of America (“GAAP”). The accompanying condensed consolidated financial statements should be read in conjunction with the consolidated financial statements at December 31, 2018 and notes included in the Company’s 2018 annual report on Form 10-K.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:	9 Months Ended
	Sep. 30, 2019
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:	NOTE 2 — SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES: ​ ADOPTION OF LEASES STANDARD ​ The Company has adopted FASB ASC 842, Leases, effective January 1, 2019, applying the transition approach which permits it to recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. Consequently, the financial statements for prior periods were not modified. At the date of adoption, the Company assessed that the adoption of the new leases standard resulted in the recognition of right of use assets and lease obligations of approximately $1,115.9 million, which was recorded in the Company’s balance sheet as of January 1, 2019. ​ During 2018, the Company developed an implementation plan with a cross-functional team, which performed a completeness assessment over the lease contracts of the Company, established new policies, procedures and internal controls related to the new standard. As result of its analysis, the Company has concluded that all of its existing lease contracts at January 1, 2019, have been classified as operating lease contracts. ​ Additionally, the Company has 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). The new standard had a material impact on the Company’s balance sheet, but did not have a material impact on its income statement and had no impact on cash flows. ​ SIGNIFICANT ACCOUNTING POLICIES ​ With the exception of the change in the Company's leases policy as a result of the adoption of ASC 842, as described above, there have been no new or material changes to the significant accounting policies discussed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018, that are of significance, or potential significance to the Company. 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.

SHORT-TERM INVESTMENTS_

SHORT-TERM INVESTMENTS:	9 Months Ended
	Sep. 30, 2019
SHORT-TERM INVESTMENTS:
SHORT-TERM INVESTMENTS:	NOTE 3 — SHORT-TERM INVESTMENTS: ​ Short-term investments were as follows ($ in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ At September 30, ​ At December 31, ​ ​ ​ 2019 2018 ​ ​ Trading securities ​ $ 1.0 ​ $ 213.1 ​ ​ Weighted average interest rate ​ 1.9 % 2.2 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Available-for-sale ​ $ 0.7 ​ $ 0.7 ​ ​ Weighted average interest rate ​ 0.9 % 0.7 % ​ Total ​ $ 1.7 ​ $ 213.8 ​ ​ ​ 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 at September 30, 2019 and December 31, 2018, included corporate bonds and asset and mortgage backed obligations. As of September 30, 2019 and December 31, 2018, 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 condensed 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 condensed consolidated statement of earnings. The following table summarizes the activity of these investments by category (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended ​ Nine months ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2019 2018 2019 2018 ​ Trading: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest earned ​ $ (*) ​ $ 0.1 ​ $ 0.1 ​ $ 0.2 ​ ​ Unrealized gain (loss) at the end of the period ​ $ (*) ​ $ (0.2) ​ $ (*) ​ $ (0.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest earned ​ (*) ​ ​ (*) ​ (*) ​ ​ (*) ​ ​ Investment redeemed ​ $ — ​ $ 0.1 ​ $ — ​ $ 0.3 ​ ​ (*) Less than $0.1 million.

INVENTORIES_

INVENTORIES:	9 Months Ended
	Sep. 30, 2019
INVENTORIES:
INVENTORIES:	NOTE 4 — INVENTORIES: ​ Inventories were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ At September 30, ​ At December 31, ​ (in millions) 2019 2018 ​ Inventory, current: ​ ​ ​ ​ ​ ​ ​ Metals at average cost: ​ ​ ​ ​ ​ ​ ​ Finished goods ​ $ 60.0 ​ $ 69.6 ​ Work-in-process ​ 276.4 ​ 256.8 ​ Ore stockpiles on leach pads ​ ​ 356.5 ​ ​ 328.0 ​ Supplies at average cost ​ 369.3 ​ 378.3 ​ Total current inventory ​ $ 1,062.2 ​ $ 1,032.7 ​ Inventory, long-term: ​ ​ ​ ​ ​ ​ ​ Ore stockpiles on leach pads ​ $ 1,224.9 ​ $ 1,177.4 ​ ​ During the nine months ended September 30, 2019 and 2018, total leaching costs capitalized as non-current inventory of ore stockpiles on leach pads amounted to $362.0 million and $393.6 million, respectively. Leaching inventories recognized in cost of sales amounted to $286.1 million and $240.0 million for the nine months September 30, 2019 and 2018, respectively.

INCOME TAXES_

INCOME TAXES:	9 Months Ended
	Sep. 30, 2019
INCOME TAXES:
INCOME TAXES:	NOTE 5 — INCOME TAXES: ​ The income tax provision and the effective income tax rate for the nine months of 2019 and 2018 consisted of ($ in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2018 ​ Statutory income tax provision ​ $ 648.0 ​ $ 698.5 ​ GILTI Tax ​ ​ — ​ ​ 15.2 ​ Peruvian royalty ​ 8.6 ​ 6.7 ​ Mexican royalty ​ 47.6 ​ 60.9 ​ Peruvian special mining tax ​ 25.8 ​ 22.3 ​ Total income tax provision ​ $ 730.0 ​ $ 803.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ Effective income tax rate ​ ​ 38.2 % ​ 39.2 % ​ These provisions include income taxes for Peru, Mexico and the United States. In addition, the Mexican royalty, the Peruvian royalty and the Peruvian special mining tax are included in the income tax provision. The decrease in the 2019 effective income tax rate from the same period in 2018 was primarily attributed to reduced GILTI tax after additional regulation was issued by the IRS and lower mining tax in Mexico over the same period of 2018, offset by small increases in the Peruvian royalty and special mining tax. ​ Peruvian royalty and special mining tax ​ The Company has accrued $25.8 million and $22.3 million of special mining tax as part of the income tax provision for the nine months of 2019 and 2018, respectively. ​ Mexican mining royalty ​ ​ ​ Accounting for uncertainty in income taxes: ​ The amount of unrecognized tax benefits (UTB’s) that, if recognized, could affect the effective tax rate was $69.5 million at September 30, 2019, and $214.5 million at December 31, 2018. The change in the UTB’s relate entirely to U.S. income tax matters and the Company has no unrecognized Peruvian or Mexican tax benefits. The $145 million reduction during the nine-month 2019 period is due to the settlement with the Internal Revenue Service (IRS) of the examination of the 2011-2013 tax years. The change in the UTB’s had been anticipated by the Company, but because of the income tax accounting rules under ASC 740, the issues had to be effectively settled and the examination closed before the effect was final and reflected in the financial statements. The audit closing resulted in an immaterial tax benefit in the financial statements that was the result of the removal of the previous accrual of interest and penalty. The remaining reversal of uncertain tax positions was offset by changes in the deferred tax asset for foreign tax credits and valuation allowance. ​ The Internal Revenue Service field audit of 2014-2016 commenced during the nine months ended September 30, 2019 and with the closing of the 2011-2013 examination, the remaining years open to examination and adjustment in the United States are 2014 and all subsequent years. ​ Management does not expect that any of the open years will result in a cash payment within the upcoming twelve months ending September 30, 2020. The Company's reasonable expectations about future resolutions of uncertain items did not materially change during the nine months ended September 30, 2019.

RELATED PARTY TRANSACTIONS_

RELATED PARTY TRANSACTIONS:	9 Months Ended
	Sep. 30, 2019
RELATED PARTY TRANSACTIONS:
RELATED PARTY TRANSACTIONS:	NOTE 6 — 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. It is the Company’s policy that the Audit Committee of the Board of Directors shall review all related party transactions. The Company is prohibited from entering or continuing a material related party transaction that has not been reviewed and approved or ratified by the Audit Committee. Receivable and payable balances with related parties are shown below (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ At September 30, ​ At December 31, ​ ​ 2019 2018 ​ Related parties receivable current: ​ ​ ​ ​ ​ ​ ​ Grupo Mexico and affiliates: ​ ​ ​ ​ ​ ​ ​ Asarco LLC ​ $ 9.0 ​ $ 74.4 ​ Americas Mining Corporation (“AMC”) ​ ​ — ​ ​ 11.0 ​ AMMINCO Apoyo Administrativo, S.A. de C.V. (“AMMINCO”) ​ 0.1 ​ 0.2 ​ Compania Perforadora Mexico S.A.P.I. de C.V. and affiliates ​ 0.4 ​ 1.4 ​ Ferrocarril Mexicano, S.A. de C.V. ​ — ​ 0.1 ​ Grupo Mexico ​ 2.7 ​ 2.7 ​ Mexico Generadora de Energia S. de R.L. ("MGE") ​ ​ 9.1 ​ ​ 10.3 ​ Mexico Proyectos y Desarrollos, S.A. de C.V. and affiliates ​ ​ 0.5 ​ ​ 0.6 ​ Related to the controlling group: ​ ​ ​ ​ ​ ​ ​ Boutique Bowling de Mexico S.A. de C.V. ​ ​ 0.1 ​ ​ 0.3 ​ Mexico Transportes Aereos, S.A. de C.V. ("Mextransport") ​ ​ 0.3 ​ ​ 0.1 ​ Operadora de Cinemas S.A. de C.V. ​ ​ 0.1 ​ ​ 0.4 ​ ​ ​ $ 22.3 ​ $ 101.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ Related parties receivable non-current: ​ ​ ​ ​ ​ ​ ​ Grupo Mexico and affiliates: ​ ​ ​ ​ ​ ​ ​ Asarco LLC ​ $ 60.0 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ Related parties payable: ​ ​ ​ ​ ​ ​ ​ Grupo Mexico and affiliates: ​ ​ ​ ​ ​ ​ ​ Asarco LLC ​ $ 15.0 ​ $ 4.1 ​ AMMINCO ​ ​ 4.0 ​ ​ 8.0 ​ Eolica El Retiro, S.A.P.I. de C.V. ​ 0.3 ​ 1.0 ​ Ferrocarril Mexicano S.A. de C.V. ​ 4.8 ​ 6.4 ​ Grupo Mexico ​ 0.2 ​ 0.6 ​ MGE ​ ​ 34.9 ​ ​ 40.6 ​ Mexico Proyectos y Desarrollos S.A. de C.V. and affiliates ​ ​ 18.0 ​ ​ 14.4 ​ Related to the controlling group: ​ ​ ​ ​ ​ ​ ​ Boutique Bowling de Mexico S.A. de C.V. ​ 0.2 ​ 0.1 ​ Operadora de Cinemas S.A. de C.V. ​ ​ 0.1 ​ ​ 0.1 ​ ​ ​ $ 77.5 ​ $ 75.3 ​ ​ Purchase and sale activity: ​ Grupo Mexico and affiliates: ​ The following table summarizes the purchase and sale activities with Grupo Mexico and its affiliates in the nine months ended September 30, 2019 and 2018 (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2018 Purchase activity ​ ​ ​ ​ ​ ​ Asarco LLC ​ $ 32.2 ​ $ 30.0 AMMINCO ​ ​ 6.4 ​ ​ — Eolica El Retiro, S.A.P.I. de C.V. ​ 2.9 ​ 2.2 Ferrocarril Mexicano, S.A. de C.V. ​ 35.1 ​ 33.0 Grupo Mexico ​ ​ 7.9 ​ ​ 13.5 MGE ​ 147.3 ​ 144.4 Mexico Proyectos y Desarrollos S.A. de C.V. and affiliates ​ 56.4 ​ 63.1 Total purchases ​ $ 288.2 ​ $ 286.2 Sales activity ​ ​ ​ ​ ​ ​ Asarco LLC ​ $ 10.6 ​ $ 82.8 Ferrocarril Mexicano, S.A. de C.V. ​ 0.1 ​ — MGE ​ ​ 33.3 ​ ​ 52.3 Total sales ​ $ 44.0 ​ $ 135.1 ​ 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´s Mexican operations pay Grupo Mexico and the Company´s Peruvian operations pay AMMINCO for these services and expect to continue requiring these services in the future. ​ In the nine months ended September 30, 2019, the Company made donations of $8.9 million 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. ​ In addition, in December 2018, in accordance with the Company´s tax sharing agreement with its parent, the Company´s Peruvian operations advanced $11 million to AMC for the payment of the Company’s portion of the GILTI tax that later was determined not to be necessary. This amount was reimbursed to the Company in the first quarter of 2019. ​ 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 Proyectos y Desarrollos, S.A. de C.V. and its affiliates, which are all subsidiaries of Grupo Mexico. ​ The Company’s Mexican operations purchased scrap and other residual copper mineral from Asarco LLC, and 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 6.2% of its power output to third-party energy users; compared to 22% at September 30, 2018. ​ 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. Eolica el Retiro is a windfarm with 37 wind turbines. This company started operations in January 2014 and started to sell power to Industrial Minera Mexico and subsidiaries (IMMSA) and other subsidiaries of Grupo Mexico in the third quarter of 2014. Currently, Eolica el Retiro is supplying approximately 25.4% of its power output to IMMSA. ​ The Company sold copper cathodes, rod and anodes, as well as sulfuric acid, silver, gold and lime to Asarco LLC. ​ 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 is Libor plus 200 basis points, 4.08513%, which will be reviewed annually. As of September 30, 2019, $60.0 million is recorded as other non-current asset and $2.0 million, as current asset in the condensed consolidated balance sheet. ​ In addition, the Company received fees for building rental and maintenance services provided to Mexico Proyectos y Desarrollos, S.A. de C.V. and its affiliates and for natural gas and services provided to MGE; all subsidiaries of Grupo Mexico. ​ Companies with relationships to the controlling group: ​ The following table summarizes the purchase and sales activities with other Larrea family companies in the nine months ended September 30, 2019 and 2018 (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2018 Purchase activity ​ ​ ​ ​ ​ ​ Boutique Bowling de Mexico S.A. de C.V. ​ $ 0.3 ​ $ 0.2 Mextransport ​ ​ 1.1 ​ ​ 1.1 Operadora de Cinemas S.A. de C.V. ​ ​ 0.1 ​ ​ 0.1 Total purchases ​ $ 1.5 ​ $ 1.4 ​ ​ ​ ​ ​ ​ ​ Sales activity ​ ​ ​ ​ ​ ​ Boutique Bowling de Mexico S.A. de C.V. ​ $ 0.1 ​ $ 0.2 Empresarios Industriales de Mexico, S.A. de C.V. ​ ​ 0.2 ​ ​ — Mextransport ​ ​ 1.3 ​ ​ 1.2 Operadora de Cinemas S.A. de C.V. ​ ​ 0.1 ​ ​ 0.1 Total sales ​ $ 1.7 ​ $ 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 provided to Boutique Bowling de Mexico S.A. de C.V., Operadora de Cinemas S.A. de C.V and Mextransport. The Company´s Mexican operations also 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. ​ In the nine months of 2019, the Company did not have purchase or sales activities with companies having relationships with SCC executive officers.

FINANCING_

FINANCING:	9 Months Ended
	Sep. 30, 2019
FINANCING:
FINANCING:	NOTE 7 — FINANCING: ​ New Minera Mexico S.A. de C.V. 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, which is being amortized over the term of the related debt. This debt was issued in one tranche, due in 2050 at an annual interest rate of 4.5%. Interest on the notes will be 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 will constitute Minera Mexico general unsecured obligations. ​ 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 condensed consolidated balance sheet. ​ In connection with the transaction, on September 26, 2019, Minera Mexico entered into a supplemental indenture with Wells Fargo Bank, National Association, as trustee, which provide 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 the Minera Mexico's assets. ​ Credit risk rating: ​ On September 19, 2019 Moody’s investors service assigned Baa2 as debt rating on the new notes issued. Also on September 19, 2019 Fitch and Standard & Poor’s ratings services assigned its ‘BBB+’, as debt rating on the new notes issued. ​ ​

LEASES_

LEASES:	9 Months Ended
	Sep. 30, 2019
LEASES:
LEASES:	NOTE 8 — LEASES: ​ The Company has operating leases for power generating facilities, vehicles and properties. Leases with an initial term of 12 months or less, underlying asset value of $10,000 or less and total nominal contract value of $100,000 or less are not recorded on the balance sheet; 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 3.65%. ​ The operating lease expense recognized in the nine months ended September 30, 2019 was classified as follows (in millions): ​ ​ ​ ​ ​ Classification 2019 Cost of sales (exclusive of depreciation, amortization and depletion) $ 86.8 Selling, general and administrative ​ 0.1 Exploration ​ 0.1 Total lease expense $ 87.0 ​ The Company’s short-term lease costs for the nine months ended September 30, 2019 was $0.3 million. ​ Maturities of lease liabilities were as follows: ​ ​ ​ ​ ​ ​ ​ Lease liabilities Year (in millions) 2019 $ 28.9 2020 ​ 115.4 2021 ​ 115.3 2022 ​ 112.2 2023 ​ 111.1 After 2023 ​ 929.2 Total lease payments $ 1,412.1 Less: interest on lease liabilities ​ (350.3) Present value of lease payments $ 1,061.8 ​

ASSET RETIREMENT OBLIGATION_

ASSET RETIREMENT OBLIGATION:	9 Months Ended
	Sep. 30, 2019
ASSET RETIREMENT OBLIGATION:
ASSET RETIREMENT OBLIGATION:	​ NOTE 9 — 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 . Currently and for the near-term future, the Company has pledged the value of its Lima office complex and a warehouse in Lima as support for this obligation. The accepted values of these facilities, for this purpose, are of ​ 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 a constructive obligation presently exists based on the remediation requirements caused by 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 2018, the Company made a change in the estimate for the asset retirement obligation in its Mexican operations, mainly due to a change in the discount rate used to determine such obligation. The effect of this change was a reduction in the asset retirement obligation of $10.4 million, which was recorded in the second quarter of 2018. ​ The following table summarizes the asset retirement obligation activity for the nine months ended September 30, 2019 and 2018 (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2018 Balance as of January 1 ​ $ 217.7 ​ $ 222.5 Changes in estimates ​ 25.2 ​ (15.6) Closure payments ​ (0.8) ​ — Accretion expense ​ 9.5 ​ 8.9 Balance as of September 30, ​ $ 251.6 ​ $ 215.8 ​

BENEFIT PLANS_

BENEFIT PLANS:	9 Months Ended
	Sep. 30, 2019
BENEFIT PLANS:
BENEFIT PLANS:	​ NOTE 10 — BENEFIT PLANS: ​ Post retirement defined benefit plans: ​ The Company has two noncontributory defined benefit pension plans covering former salaried employees in the United States and certain former expatriate employees in Peru. 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 components of net periodic benefit costs for the nine months ended September 30, 2019 and 2018 are as follows (in millions): ​ ​ ​ ​ ​ ​ ​ ​ (in millions) 2019 2018 Service cost ​ $ 0.8 ​ $ 0.8 Interest cost ​ 1.3 ​ 1.2 Expected return on plan assets ​ (2.6) ​ (2.7) Amortization of prior service cost / (credit) ​ 0.2 ​ 0.2 Amortization of net loss/(gain) ​ 0.1 ​ 0.1 Net periodic benefit cost ​ $ (0.2) ​ $ (0.4) ​ Post-retirement health care plans: ​ 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 periodic benefit cost for the nine months ended September 30, 2019 and 2018 are as follows (in millions): ​ ​ ​ ​ ​ ​ ​ ​ (in millions) 2019 2018 Interest cost ​ $ 0.7 ​ $ 0.7 Amortization of net loss (gain) ​ (0.2) ​ (0.2) Amortization of prior service cost/ (credit) ​ (*) ​ (*) Net periodic benefit cost ​ $ 0.5 ​ $ 0.5 (*) amount is lower than $0.1 million

COMMITMENTS AND CONTINGENCIES_

COMMITMENTS AND CONTINGENCIES:	9 Months Ended
	Sep. 30, 2019
COMMITMENTS AND CONTINGENCIES:
COMMITMENTS AND CONTINGENCIES:	NOTE 11 — 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 the nine months ended September 30, 2019 and 2018 were as follows (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2018 Peruvian operations ​ $ 12.9 ​ $ 38.0 Mexican operations ​ 55.9 ​ 35.3 ​ ​ $ 68.8 ​ $ 73.3 ​ Peruvian operations ​ Air Quality Standards (“AQS”): In June 2017, MINAM enacted a supreme decree which defined new AQS for daily sulfur dioxide in the air. As of September 30, 2019, the Company maintains a lower daily average level of µg/m3 (micrograms per cubic meter) of SO2, than those required by the AQS. ​ Soil Environmental Quality Standards (“SQS”): In 2013, the Peruvian government enacted SQS applicable to any existing facility or project that generates or could generate the risk of soil contamination in its area of operation or influence. In March 2014, MINAM issued a supreme decree, which established additional provisions for the gradual implementation of SQS. ​ In accordance with the regulatory requirements, the Company has been working on a characterization phase and a Soil Decontamination Plan (“SDP”) for environmentally impacted sites in each of its operating units (Toquepala, Cuajone, and Ilo) with the assistance of consulting companies. The Toquepala and Cuajone SDP have been presented to the authorities for review and approval in the third quarter of 2019, and the Ilo SDP will be submitted during the last quarter of 2019. ​ While the Company believes that there is a reasonable possibility that a potential loss contingency may exist, it cannot currently reasonably estimate the amount of the contingency. The Company believes that a reasonable determination of the loss will be possible once the characterization study and the SDP are substantially completed and approved, which is expected for 2020. At that time the Company will be in a position to estimate the remediation cost. Furthermore, the Company does not believe that it can estimate a reasonable range of possible costs until the noted studies have substantially progressed and therefore is not able to disclose a range of costs that is meaningful. ​ 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, giving 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 establish three categories of collective actions by means of which 30 or more people claiming injury derived from environmental, consumer protection, financial services and economic competition issues will be considered to be sufficient in order to have a legitimate interest to seek through a civil procedure restitution or economic compensation or suspension of the activities from which the alleged injury derived. 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, at the Company´s Marine Terminal in Guaymas, Sonora, there was an incident 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, the discharge was quickly diluted, the sulfuric acid was naturally and immediately neutralized. As a result the discharge was considered harmless, and it was found that neither the flora nor fauna of the port area were affected, according to the report from the Ministry of Navy. ​ On July 10, 2019, the Mexican Environmental Protection Agency (“PROFEPA”) made a first inspection of the area, concluding that the Company executed all the correct 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 related only to 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, previous to the 1988 Mexican General Law of Ecological Balance and the Protection of the Environment. Therefore, these licenses are not a requirement for companies that have being operating before the mentioned law. In addition, PROFEPA’s awarded in 2009 a certification of “Clean Industry and Environmental Quality” for such facility; which was subsequently renewed four times (for periods of two years each). ​ The Company does not know the reasons or causes for this partial and temporary closure, but it will continue contributing with the environmental authorities with all the necessary elements in order to provide certainty with respect to the operation, in strict adherence to environmental regulations. The Company expects the environmental authorities to revoke the partial temporary shutdown, once they clarify their concerns. Currently, the Company does not expect any impact on its operations. ​ The Company believes that all of its facilities in Peru and Mexico are in material compliance with applicable environmental, mining and other laws and regulations. The Company also believes that continued compliance with environmental laws of Mexico and Peru will not have a material adverse effect on the Company’s business, properties, or result of operations. ​ Litigation matters ​ Peruvian operations ​ The Tia Maria Mining Project ​ There are four 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 which approved the Environmental Impact Assessment of the project; (ii) the cancellation of the project and the withdrawal of mining activities in the area and (iii) to declare null and void the mining concession application of the Tia Maria project. 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) and Junta de Usuarios del Valle del Tambo (filed April 30, 2015). ​ 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 September 30, 2019, 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. As of September 30, 2019, the case remains pending resolution. ​ The Guillen Lopez case is currently before the lower court. On July 19, 2019, the oral hearing took place. As of September 30, 2019, 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. As of September 30, 2019, 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 constructed and operated the tailings dams with proper governmental authorization, since 1995. 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 September 30, 2019, the case remains 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 of 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 the environmental damages. During the second quarter of 2018, the criminal complaint was dismissed. This decision was appealed and remains pending resolution as of September 30, 2019. ​ 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 September 30, 2019, three lawsuits continue in process: two were filed by Acciones Colectivas de Sinaloa, A.C. and one was filed by Defensa Colectiva, A.C.; who have requested 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 Domínguez 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. During 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. During the last quarter of 2018, BVC was served with other three civil action lawsuits, claiming similar damages, such lawsuits were filed by Los Corrales de la Estancia, S.C. de R.L.; Jose Antonio Navarro; Jesus Maria Peña Molina, et al; those actions were dismissed by the court, because of their expiration. As of September 30, 2019, forty-five cases remain pending resolution. ​ During 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 which established two lawsuits, Francisco Ramon Miranda, et al and Jesus David Lopez Peralta et al. During 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. During 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 which established 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 six months period; (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 promoted by Maria de los Angeles Enriquez Bacame and Norberto Bustamante have been dismissed and closed without prejudice to the Company. As of September 30, 2019, the remaining cases are still pending resolution. ​ It is not currently possible to determine the extent of the damages sought in these state and federal lawsuits but the Company considers that these lawsuits are without merit. Accordingly, the Company is vigorously defending against them. Nevertheless, the Company considers 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 of its 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 August 2019, SCC, the current and former Directors, and Grupo Mexico responded to the complaint by filing motions to dismiss. The plaintiff has until on or before October 25, 2019 to respond to the motions. Because SCC has not formed a conclusion as to whether an unfavorable outcome is either probable or remote, SCC expresses no opinion as to the likelihood of an unfavorable outcome or the amount or range of any possible loss to SCC. ​ Labor matters ​ Peruvian operations: ​ As of September 30, 2019, the Company continues negotiations for a collective bargaining agreement with the remaining unsigned union. ​ 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 will 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 again the election results from February 28, 2018; in which the National Federation of Independent Unions won by a majority. The Company is working on a rehabilitation plan to restore operations at the San Martin mine with a budget of $87 million. At September 30, 2019 the plan is in progress with a total expense of $70.2 million. ​ 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 September 30, 2019, 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. ​ 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 $1,400 million. This permit was obtained after completing an exhausting review process, complying with all established regulatory requirements and addressing all observations raised. ​ 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 to resolve on these complaints. The Mining Council temporarily suspended the construction permit on August 8, 2019 until a decision is reached on the complaints. On October 7, 2019, as part of the process, the Mining Council conducted a hearing on the complaints and the Company position. The Company strongly believes the noted claims have no merit and, consequently, expects a favorable decision on this matter. ​ The Company´s commitment is to guarantee the population of Islay that the Tia Maria project will not adversely affect other local economic activities. The project will use only desalinated seawater for its operations and, for the transportation of its supplies and copper production, the Company will build an 32 kilometer industrial railway and an access road at a safe distance from the Tambo Valley. ​ The Company reiterates its commitment to delay the construction of the project until it has established, in coordination with the government, a common ground for dialogue with the neighboring communities to address any concerns and ​ The Company´s social programs in education, healthcare and productive development will continue to improve the quality-of-life and the agricultural and livestock activities in the Tambo Valley, as well as the fishing and tourism in Islay. During the construction and operation phase, hiring local labor will be a priority. The Company has successfully launched in June the free technical training program “Forging the Future”, which will benefit 700 persons in this province in 2019-20. After training, the participants will be eligible to apply for one of the estimated 9,000 jobs (3,600 direct and 5,400 indirect) required during the Tia Maria construction phase. The Company strongly believes that the initiation of construction activities for Tia Maria will generate significant economic opportunities for the Islay province and the Arequipa region. ​ When in operation, the Company expects Tia Maria will generate a significant contribution through mining royalties and taxes from day-one and will directly employ 600 workers and indirectly provide jobs to another 4,200. ​ Tia Maria´s project budget is approximately $1.4 billion, of which $336.5 million has been invested through September 30, 2019. 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, do not release any 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. ​ Toquepala Concentrator Expansion: ​ In April 2015, the construction permit for the Toquepala expansion project was approved by the MINEM. The project budget is $1,320 million, of which $1,296.8 million has been invested through September 30, 2019. This project will increase Toquepala’s annual copper production to 257,000 tons in 2019, a 51% production increase, when compared to 2018. The construction of the project was completed and the project began production in the fourth quarter of 2018. Full production was reached in the second quarter of 2019. ​ Corporate Social Responsibility: ​ The Company has a corporate social responsibility policy to maintain and promote continuity of its mining operations and obtain the best results. The main objective of this policy is to integrate its operations with the local communities in the areas of influence of its operations by creating a permanent positive relationship with them, in order to develop the optimum social conditions and to promote sustainable development in the area. Accordingly, the Company has made the following commitments: ​ Tacna Region: ​ Moquegua Region: ​ In addition, the Company has committed S/ 202.0 million (approximately $59.8 million) for the construction of six 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. ​ 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 $62.1 million in its condensed consolidated financial statements as of September 30, 2019. ​ 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 120MW 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 80MW 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 6 “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 6 “Related party transactions”. ​ Corporate operations ​ Commitment for Capital projects: ​ As of September 30, 2019, the Company has committed approximately $125.9 million for the development of its capital investment projects at its operations. ​ Tax contingency matters: ​ Tax contingencies are provided for under ASC 740-10-50-15 Uncertain tax position (see Note 5 “Income taxes”).

STOCKHOLDERS' EQUITY_

STOCKHOLDERS' EQUITY:	9 Months Ended
	Sep. 30, 2019
STOCKHOLDERS' EQUITY:
STOCKHOLDERS' EQUITY:	NOTE 12 — STOCKHOLDERS’EQUITY: ​ Treasury Stock: ​ Activity in treasury stock in the nine-month period ended September 30, 2019 and 2018 is as follows (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2018 Southern Copper common shares ​ ​ ​ ​ ​ ​ Balance as of January 1, ​ $ 2,768.3 ​ $ 2,768.7 Used for corporate purposes ​ (0.4) ​ (0.4) Balance as of September 30, ​ 2,767.9 ​ 2,768.3 ​ ​ ​ ​ ​ ​ ​ Parent Company (Grupo Mexico) common shares ​ ​ ​ ​ ​ ​ Balance as of January 1, ​ 251.3 ​ 232.4 Other activity, including dividend, interest and foreign currency transaction effect ​ 20.7 ​ 17.3 Balance as of September 30, ​ 272.0 ​ 249.7 Treasury stock balance as of September 30, ​ $ 3,039.9 ​ $ 3,018.0 ​ The following table summarizes share distributions in the first nine months of 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ 2019 2018 Southern Copper common shares ​ ​ ​ ​ Directors’ Stock Award Plan ​ 14,400 ​ 16,000 ​ ​ ​ ​ ​ Parent Company (Grupo Mexico) common shares ​ ​ ​ ​ Employee stock purchase plan (shares in millions) ​ 0.4 ​ 1.3 ​ Southern Copper Common Shares: ​ At September 30, 2019 and at December 31, 2018, there were in treasury 111,537,217 and 111,551,617 shares of SCC’s common stock, respectively. ​ 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. ​ The NYSE closing price of SCC common shares at September 30, 2019 was $34.13 and the maximum number of shares that the Company could purchase at that price is 2.4 million shares. ​ As a result of the repurchase of shares of SCC’s common stock, Grupo Mexico’s direct and indirect ownership was 88.9% as of September 30, 2019. There has not been any activity in the SCC share repurchase program since the third quarter of 2016. ​ 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 Board of Directors and the stockholders approved a five-year extension of the Plan until January 29, 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. ​ Parent Company common shares: ​ At September 30, 2019 and at December 31, 2018 there were in treasury 94,147,164 and 100,188,809 of Grupo Mexico’s common shares, respectively. ​ Employee Stock Purchase Plan: ​ 2015 Plan ​ 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 nine months 2019 and 2018 and the unrecognized compensation expense under this plan were as follows (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2018 Stock based compensation expense ​ $ 0.4 ​ $ 0.4 Unrecognized compensation expense ​ $ 2.2 ​ $ 2.8 ​ The following table presents the activity of this plan for the nine months ended September 30, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ Unit Weighted Average ​ ​ Shares ​ Grant Date Fair Value Outstanding shares at January 1, 2019 1,840,336 ​ $ 2.63 Granted — ​ — Exercised (437,386) ​ $ 2.63 Forfeited — ​ — Outstanding shares at September 30, 2019 1,402,950 ​ $ 2.63 Outstanding shares at January 1, 2018 2,293,120 ​ $ 2.63 Granted — ​ — Exercised (306,817) ​ $ 2.63 Forfeited — ​ — Outstanding shares at September 30, 2018 1,986,303 ​ $ 2.63 ​ 2018 Plan: ​ 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 nine months ended September 30, 2019 and the unrecognized compensation expense under this plan were as follows (in millions): ​ ​ ​ ​ ​ ​ 2019 Stock based compensation expense ​ $ 0.5 Unrecognized compensation expense ​ $ 4.7 ​ ​ The following table presents the stock award activity of this plan for the nine months ended September 30, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unit Weighted Average ​ Shares Grant Date Fair Value Outstanding shares at January 1, 2019 2,782,424 1.86 Granted 1,238,169 1.86 Exercised — — Forfeited — ​ — Outstanding shares at September 30, 2019 4,020,593 ​ 1.86 ​ Non-controlling interest: ​ The following table presents the non-controlling interest activity for the nine months ended September 30, 2019 and 2018 (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2018 Balance as of January 1, $ 45.4 $ 41.7 Net earnings ​ 4.7 ​ 3.9 Dividend paid ​ (1.1) ​ (1.2) Balance as of September 30, $ 49.0 $ 44.4 ​

FAIR VALUE MEASUREMENT_

FAIR VALUE MEASUREMENT:	9 Months Ended
	Sep. 30, 2019
FAIR VALUE MEASUREMENT:
FAIR VALUE MEASUREMENT:	​ NOTE 13 — 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 condensed consolidated balance sheet as of September 30, 2019 and December 31, 2018 (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ At September 30, 2019 ​ At December 31, 2018 ​ Carrying Value Fair Value Carrying Value Fair Value Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Long-term debt level 1 ​ ​ 6,190.1 ​ ​ 7,452.7 ​ ​ 5,210.7 ​ ​ 5,540.0 Long-term debt level 2 ​ ​ 750.0 ​ ​ 778.0 ​ ​ 749.4 ​ ​ 761.7 Total long-term debt ​ $ 6,940.1 ​ $ 8,230.7 ​ $ 5,960.1 ​ $ 6,301.7 ​ 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, the notes due 2020 and the notes due 2022, which qualify as Level 2 in the fair value hierarchy as they are based on quoted prices in markets that are not active. ​ Fair values of assets and liabilities measured at fair value on a recurring basis were calculated as follows as of September 30, 2019 and December 31, 2018 (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value at Measurement Date Using: ​ ​ ​ ​ ​ Significant ​ ​ ​ ​ Fair Value ​ Quoted prices in ​ other ​ Significant ​ ​ as of ​ active markets for ​ observable ​ unobservable ​ ​ September 30, ​ identical assets ​ inputs ​ inputs Description ​ 2019 ​ (Level 1) ​ (Level 2) ​ (Level 3) Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Short term investment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ — ​ $ 1.0 ​ $ 1.0 ​ $ — ​ $ — — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate bonds ​ — ​ ​ — ​ ​ — ​ ​ — Asset backed securities ​ 0.4 ​ ​ — ​ ​ 0.4 ​ ​ — Mortgage backed securities ​ 0.3 ​ ​ — ​ ​ 0.3 ​ ​ — Accounts receivable: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ — — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Provisionally priced sales: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Copper ​ 544.7 ​ 544.7 ​ ​ — ​ ​ — Molybdenum ​ 166.6 ​ 166.6 ​ — ​ ​ — Total ​ $ 713.0 ​ $ 712.3 ​ $ 0.7 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 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 ​ 2018 ​ (Level 1) ​ (Level 2) ​ (Level 3) Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Short term investment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ — ​ $ 213.1 ​ $ 213.1 ​ $ — ​ $ — — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate bonds ​ — ​ ​ — ​ ​ — ​ ​ — Asset backed securities ​ 0.4 ​ ​ — ​ 0.4 ​ ​ — Mortgage backed securities ​ 0.3 ​ ​ — ​ ​ 0.3 ​ ​ — Accounts receivable: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Provisionally priced sales: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Copper ​ 274.3 ​ 274.3 ​ ​ — ​ ​ — Molybdenum ​ 107.4 ​ 107.4 ​ — ​ ​ — Total ​ $ 595.5 ​ $ 594.8 ​ $ 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.

REVENUE_

REVENUE:	9 Months Ended
	Sep. 30, 2019
REVENUE:
REVENUE:	NOTE 14 — REVENUE: ​ On January 1, 2018, the Company adopted FASB Accounting Standards Codification Topic 606 (“ASC 606”), Revenue from Contracts with Customers. Upon adoption by the Company, no cumulative effect adjustment was required to be recognized, as the adoption of the standard did not result in a change to the way the Company recognizes its revenue. ​ The Company’s net sales were $5,431.0 million in the nine months ended September 30, 2019, compared to $5,402.1 million in the same period of 2018. The geographic breakdown of the Company’s sales is as follows (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2019 ​ ​ ​ ​ Mexican ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexican ​ IMMSA ​ Peruvian ​ Corporate & ​ ​ ​ ​ Open-Pit Unit Operations Elimination Consolidated The Americas: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexico ​ $ 338.3 ​ $ 81.8 ​ $ — ​ $ (18.6) ​ $ 401.5 United States ​ 280.4 ​ 3.1 ​ 58.7 ​ — ​ 342.2 Peru ​ — ​ — ​ 75.2 ​ — ​ 75.2 Brazil ​ — ​ 1.0 ​ 48.7 ​ — ​ 49.7 Chile ​ 0.1 ​ — ​ 64.4 ​ — ​ 64.5 Other American countries ​ 10.1 ​ 0.7 ​ 0.4 ​ — ​ 11.2 Europe: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Switzerland ​ 171.1 ​ 11.3 ​ 81.5 ​ — ​ 263.9 Italy ​ 5.7 ​ 2.0 ​ 54.6 ​ — ​ 62.3 Spain ​ 46.7 ​ — ​ — ​ — ​ 46.7 Other European countries ​ 24.8 ​ 4.4 ​ 38.0 ​ — ​ 67.2 Asia: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Singapore ​ 68.0 ​ 2.3 ​ 212.8 ​ — ​ 283.1 Japan ​ 21.3 ​ — ​ 106.6 ​ — ​ 127.9 Other Asian countries ​ 15.9 ​ 0.1 ​ 48.1 ​ — ​ 64.1 Total ​ $ 982.4 ​ $ 106.7 ​ $ 789.0 ​ $ (18.6) ​ $ 1,859.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2018 ​ ​ ​ ​ ​ Mexican ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexican ​ IMMSA ​ Peruvian ​ Corporate & ​ ​ ​ ​ Open-Pit Unit Operations Elimination Consolidated The Americas: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexico ​ $ 329.3 ​ $ 86.4 ​ $ — ​ $ (17.2) ​ $ 398.5 United States ​ 263.1 ​ 0.5 ​ 40.8 ​ ​ — ​ ​ 304.4 Peru ​ — ​ — ​ 92.6 ​ ​ — ​ ​ 92.6 Brazil ​ — ​ 6.6 ​ 55.9 ​ ​ — ​ ​ 62.5 Chile ​ — ​ — ​ 42.4 ​ ​ — ​ ​ 42.4 Other American countries ​ 15.2 ​ 0.5 ​ — ​ ​ — ​ ​ 15.7 Europe: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Switzerland ​ ​ 141.4 ​ ​ 6.8 ​ ​ 31.4 ​ ​ — ​ ​ 179.6 Italy ​ ​ 5.1 ​ ​ 3.4 ​ ​ 64.3 ​ ​ — ​ ​ 72.8 Spain ​ ​ 42.0 ​ ​ — ​ ​ — ​ ​ — ​ ​ 42.0 Other European countries ​ ​ 74.0 ​ ​ 2.9 ​ ​ 24.3 ​ ​ — ​ ​ 101.2 Asia: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Singapore ​ ​ 104.9 ​ ​ — ​ ​ 164.1 ​ ​ — ​ ​ 269.0 Japan ​ ​ (4.7) ​ ​ — ​ ​ 114.0 ​ ​ — ​ ​ 109.3 Other Asian countries ​ ​ 24.8 ​ ​ 0.2 ​ ​ 8.7 ​ ​ — ​ ​ 33.7 Total ​ $ 995.1 ​ $ 107.3 ​ $ 638.5 ​ $ (17.2) ​ $ 1,723.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2019 ​ ​ ​ ​ Mexican ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexican ​ IMMSA ​ Peruvian ​ Corporate & ​ ​ ​ ​ Open-Pit Unit Operations Elimination Consolidated The Americas: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexico ​ $ 1,002.5 ​ $ 261.3 ​ $ — ​ $ (63.9) ​ $ 1,199.9 United States ​ 817.3 ​ 6.2 ​ 87.0 ​ — ​ 910.5 Peru ​ 1.6 ​ — ​ 254.0 ​ — ​ 255.6 Brazil ​ — ​ 13.3 ​ 141.6 ​ — ​ 154.9 Chile ​ 1.3 ​ — ​ 143.6 ​ — ​ 144.9 Other American countries ​ 34.1 ​ 2.0 ​ 3.1 ​ — ​ 39.2 Europe: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Switzerland ​ 579.4 ​ 28.4 ​ 264.9 ​ — ​ 872.7 Italy ​ 42.7 ​ 10.3 ​ 165.6 ​ — ​ 218.6 Spain ​ 139.0 ​ — ​ — ​ — ​ 139.0 Other European countries ​ 70.3 ​ 19.2 ​ 159.0 ​ — ​ 248.5 Asia: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Singapore ​ 198.5 ​ 8.7 ​ 460.6 ​ — ​ 667.8 Japan ​ 37.3 ​ — ​ 350.6 ​ — ​ 387.9 Other Asian countries ​ 85.1 ​ 0.7 ​ 105.7 ​ — ​ 191.5 Total ​ $ 3,009.1 ​ $ 350.1 ​ $ 2,135.7 ​ $ (63.9) ​ $ 5,431.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2018 ​ ​ ​ ​ ​ Mexican ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexican ​ IMMSA ​ Peruvian ​ Corporate & ​ ​ ​ ​ Open-Pit Unit Operations Elimination Consolidated The Americas: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexico ​ $ 1,026.2 ​ $ 307.0 ​ $ — ​ $ (55.6) ​ $ 1,277.6 United States ​ 782.4 ​ 6.1 ​ 139.1 ​ ​ — ​ ​ 927.6 Peru ​ — ​ — ​ 292.7 ​ ​ — ​ ​ 292.7 Brazil ​ — ​ 28.8 ​ 183.2 ​ ​ — ​ ​ 212.0 Chile ​ — ​ — ​ 102.1 ​ ​ — ​ ​ 102.1 Other American countries ​ 41.6 ​ 2.9 ​ 1.2 ​ ​ — ​ ​ 45.7 Europe: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Switzerland ​ ​ 340.4 ​ ​ 33.9 ​ ​ 105.8 ​ ​ — ​ ​ 480.1 Italy ​ ​ 18.2 ​ ​ 16.8 ​ ​ 224.6 ​ ​ — ​ ​ 259.6 Spain ​ ​ 130.7 ​ ​ — ​ ​ — ​ ​ — ​ ​ 130.7 Other European countries ​ ​ 195.7 ​ ​ 13.4 ​ ​ 72.4 ​ ​ — ​ ​ 281.5 Asia: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Singapore ​ ​ 389.0 ​ ​ — ​ ​ 443.1 ​ ​ — ​ ​ 832.1 Japan ​ ​ 68.7 ​ ​ — ​ ​ 333.2 ​ ​ — ​ ​ 401.9 Other Asian countries ​ ​ 132.0 ​ ​ 0.7 ​ ​ 25.8 ​ ​ — ​ ​ 158.5 Total ​ $ 3,124.9 ​ $ 409.6 ​ $ 1,923.2 ​ $ (55.6) ​ $ 5,402.1 ​ The following table presents information regarding the sales value by reporting segment of the Company’s significant products for the three and nine months ended September 30, 2019 and 2018 (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2019 ​ ​ ​ Mexican ​ ​ ​ ​ ​ ​ ​ ​ Mexican IMMSA Peruvian Corporate, Other & Total ​ ​ Open-pit ​ Unit ​ Operations ​ Eliminations ​ Consolidated Copper ​ $ 809.6 ​ $ 11.5 ​ $ 667.3 ​ $ (11.0) ​ $ 1,477.4 Molybdenum ​ 91.2 ​ — ​ 65.3 ​ — ​ 156.5 Silver ​ 49.8 ​ 24.7 ​ 23.1 ​ (9.0) ​ 88.6 Zinc ​ — ​ 54.6 ​ — ​ 2.6 ​ 57.2 Other ​ 31.8 ​ 15.9 ​ 33.3 ​ (1.2) ​ 79.8 Total ​ $ 982.4 ​ $ 106.7 ​ $ 789.0 ​ $ (18.6) ​ $ 1,859.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2018 ​ ​ ​ Mexican ​ ​ ​ ​ ​ ​ ​ ​ Mexican IMMSA Peruvian Corporate, Other & Total ​ ​ Open-pit ​ Unit ​ Operations ​ Eliminations ​ Consolidated Copper ​ $ 840.8 ​ $ 9.9 ​ $ 550.8 ​ $ (10.0) ​ $ 1,391.5 Molybdenum ​ 89.2 ​ — ​ 48.4 ​ — ​ 137.6 Zinc ​ — ​ 63.2 ​ — ​ — ​ 63.2 Silver ​ 42.5 ​ 19.0 ​ 16.8 ​ (6.6) ​ 71.7 Other ​ 22.6 ​ 15.2 ​ 22.5 ​ (0.6) ​ 59.7 Total ​ $ 995.1 ​ $ 107.3 ​ $ 638.5 ​ $ (17.2) ​ $ 1,723.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2019 ​ ​ ​ Mexican ​ ​ ​ ​ ​ ​ ​ ​ Mexican IMMSA Peruvian Corporate, Other & Total ​ ​ Open-pit ​ Unit ​ Operations ​ Eliminations ​ Consolidated Copper ​ $ 2,504.9 ​ $ 34.5 ​ $ 1,840.7 ​ $ (38.2) ​ $ 4,341.9 Molybdenum ​ 274.8 ​ — ​ 154.6 ​ — ​ 429.4 Silver ​ 137.6 ​ 59.1 ​ 58.7 ​ (21.3) ​ 234.1 Zinc ​ — ​ 211.3 ​ — ​ (1.6) ​ 209.7 Other ​ 91.8 ​ 45.2 ​ 81.7 ​ (2.8) ​ 215.9 Total ​ $ 3,009.1 ​ $ 350.1 ​ $ 2,135.7 ​ $ (63.9) ​ $ 5,431.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2018 ​ ​ ​ Mexican ​ ​ ​ ​ ​ ​ ​ ​ Mexican IMMSA Peruvian Corporate, Other & Total ​ ​ Open-pit ​ Unit ​ Operations ​ Eliminations ​ Consolidated Copper ​ $ 2,661.9 ​ $ 37.0 ​ $ 1,686.7 ​ $ (32.2) ​ $ 4,353.4 Molybdenum ​ 254.2 ​ — ​ 124.3 ​ — ​ 378.5 Zinc ​ — ​ 253.0 ​ — ​ (0.1) ​ 252.9 Silver ​ 133.2 ​ 63.4 ​ 50.6 ​ (21.2) ​ 226.0 Other ​ 75.6 ​ 56.2 ​ 61.6 ​ (2.1) ​ 191.3 Total ​ $ 3,124.9 ​ $ 409.6 ​ $ 1,923.2 ​ $ (55.6) ​ $ 5,402.1 ​ ​ The opening and closing balances of receivables by reporting segment of the Company were as follows (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexican ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexican IMMSA Peruvian Corporate & ​ ​ ​ ​ Open-Pit ​ Unit ​ Operations ​ Elimination ​ Consolidated ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of September 30, 2019: ​ ​ ​ ​ ​ Trade receivables ​ $ 430.1 ​ $ 41.8 ​ $ 370.1 ​ $ — ​ $ 842.0 Related parties, current ​ 14.1 ​ — ​ — ​ 8.2 ​ 22.3 Related parties, non-current ​ ​ 60.0 ​ ​ — ​ ​ — ​ ​ — ​ ​ 60.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2018: ​ ​ ​ ​ ​ Trade receivables ​ $ 505.9 ​ $ 50.5 ​ $ 266.0 ​ $ — ​ $ 822.4 Related parties ​ 81.6 ​ — ​ — ​ 19.9 ​ 101.5 ​ As of September 30, 2019, the Company has long-term contracts with promises to deliver the following products: ​ ​ ​ ​ Copper concentrates (in tons) 1,090,000 Copper cathodes (in tons) ​ 48,000 Molybdenum concentrates (in tons) 24,446 Sulfuric acid (in tons) 331,620 ​ Provisionally priced sales : At September 30, 2019, the Company has recorded provisionally priced sales of copper at average forward prices per pound, and molybdenum at the September 30, 2019 market price per pound. These sales are subject to final pricing based on the average monthly London Metal Exchange (“LME”), or New York Commodities Exchange (“COMEX”), copper prices and Dealer Oxide molybdenum prices in the future month of settlement. ​ Following are the provisionally priced copper and molybdenum sales outstanding at September 30, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ Sales volume Priced at ​ ​ ​ (million lbs.) ​ (per pound) ​ Month of settlement Copper ​ 210.4 ​ 2.59 ​ October 2019 through February 2020 Molybdenum ​ 14.1 ​ 11.78 ​ October through December 2019 ​ The provisional sales price adjustment included in accounts receivable and net sales at September 30, 2019 includes negative adjustments of $19.9 million and $6.0 million for copper and molybdenum, respectively. ​ 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.

SEGMENT AND RELATED INFORMATION

SEGMENT AND RELATED INFORMATION:	9 Months Ended
	Sep. 30, 2019
SEGMENT AND RELATED INFORMATION:
SEGMENT AND RELATED INFORMATION:	​ NOTE 15 — 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. ​ Financial information is regularly prepared for each of the three segments and the results of the Company’s operations are regularly reported to Senior Management on the segment basis. Senior Management of the Company focus 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 Southern Copper’s segments is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2019 ​ ​ (in millions) ​ ​ Mexican ​ ​ Corporate, other ​ ​ ​ ​ Mexican ​ IMMSA ​ Peruvian ​ and ​ ​ ​ ​ ​ Open-pit ​ Unit ​ Operations ​ eliminations ​ Consolidated Net sales outside of segments ​ $ 982.4 ​ $ 88.1 ​ $ 789.0 ​ $ — ​ $ 1,859.5 Intersegment sales ​ — ​ ​ 18.6 ​ — ​ (18.6) ​ — Cost of sales (exclusive of depreciation, amortization and depletion) ​ 390.2 ​ 80.7 ​ 452.5 ​ (16.9) ​ 906.5 Selling, general and administrative ​ 19.4 ​ 2.0 ​ 9.4 ​ 1.2 ​ 32.0 Depreciation, amortization and depletion ​ 91.1 ​ 13.7 ​ 88.4 ​ 7.1 ​ 200.3 Exploration ​ 0.5 ​ 2.3 ​ 1.9 ​ 2.2 ​ 6.9 Operating income ​ $ 481.2 ​ $ 8.0 ​ $ 236.8 ​ $ (12.2) ​ ​ 713.8 Less: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest, net ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (78.7) Other income (expense) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (6.3) Income taxes ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (241.0) Equity earnings of affiliate ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 3.5 Non-controlling interest ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1.7) Net income attributable to SCC ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 389.6 Capital investment ​ $ 59.4 ​ $ 32.1 ​ $ 88.8 ​ $ 2.4 ​ $ 182.7 Property and mine development, net ​ $ 4,691.2 ​ $ 487.6 ​ $ 3,878.7 ​ $ 337.8 ​ $ 9,395.3 Total assets ​ $ 8,093.3 ​ $ 839.3 ​ $ 5,114.6 ​ $ 2,447.2 ​ $ 16,494.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2018 ​ ​ (in millions) ​ ​ Mexican ​ ​ Corporate, other ​ ​ ​ ​ Mexican ​ IMMSA ​ Peruvian ​ and ​ ​ ​ ​ Open-pit ​ Unit ​ Operations ​ eliminations ​ Consolidated Net sales outside of segments ​ $ 995.1 ​ $ 90.1 ​ $ 638.5 ​ $ — ​ $ 1,723.7 Intersegment sales ​ — ​ 17.2 ​ — ​ (17.2) ​ — Cost of sales (exclusive of depreciation, amortization and depletion) ​ 398.8 ​ 74.7 ​ 369.3 ​ (18.8) ​ 824.0 Selling, general and administrative ​ 15.8 ​ 1.9 ​ 8.5 ​ 0.2 ​ 26.4 Depreciation, amortization and depletion ​ 95.1 ​ 11.5 ​ 61.6 ​ 2.4 ​ 170.6 Exploration ​ 0.4 ​ 1.1 ​ 2.2 ​ 2.3 ​ 6.0 Operating income ​ $ 485.0 ​ $ 18.1 ​ $ 196.9 ​ $ (3.3) ​ ​ 696.7 Less: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest, net ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (64.8) Other income (expense) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (7.6) Income taxes ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (257.9) Equity earnings of affiliate ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 4.3 Non-controlling interest ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1.3) Net income attributable to SCC ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 369.4 Capital investment ​ $ 53.7 ​ $ 10.2 ​ $ 217.7 ​ $ 0.7 ​ $ 282.3 Property and mine development, net ​ $ 4,579.5 ​ $ 433.4 ​ $ 3,745.6 ​ $ 553.3 ​ $ 9,311.8 Total assets ​ $ 8,122.7 ​ $ 974.1 ​ $ 4,754.9 ​ $ 465.0 ​ $ 14,316.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2019 ​ ​ (in millions) ​ ​ Mexican ​ ​ Corporate, other ​ ​ ​ ​ Mexican ​ IMMSA ​ Peruvian ​ and ​ ​ ​ ​ ​ Open-pit ​ Unit ​ Operations ​ eliminations ​ Consolidated Net sales outside of segments ​ $ 3,009.1 ​ $ 286.2 ​ $ 2,135.7 ​ $ — ​ $ 5,431.0 Intersegment sales ​ — ​ 63.9 ​ — ​ (63.9) ​ — Cost of sales (exclusive of depreciation, amortization and depletion) ​ 1,194.9 ​ 285.3 ​ 1,208.0 ​ (70.3) ​ 2,617.9 Selling, general and administrative ​ 51.4 ​ 6.0 ​ 28.2 ​ 5.8 ​ 91.4 Depreciation, amortization and depletion ​ 263.9 ​ 39.9 ​ 247.8 ​ 29.0 ​ 580.6 Exploration ​ 1.4 ​ 7.0 ​ 9.0 ​ 2.5 ​ 19.9 Operating income ​ $ 1,497.5 ​ $ 11.9 ​ $ 642.7 ​ $ (30.9) ​ ​ 2,121.2 Less: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest, net ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (232.5) Other income (expense) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 22.0 Income taxes ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (730.0) Equity earnings of affiliate ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 4.2 Non-controlling interest ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (4.7) Net income attributable to SCC ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 1,180.2 Capital investment ​ $ 180.5 ​ $ 79.6 ​ $ 271.5 ​ $ 4.5 ​ $ 536.1 Property and mine development, net ​ $ 4,691.2 ​ $ 487.6 ​ $ 3,878.7 ​ $ 337.8 ​ $ 9,395.3 Total assets ​ $ 8,093.3 ​ $ 839.3 ​ $ 5,114.6 ​ $ 2,447.2 ​ $ 16,494.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2018 ​ ​ (in millions) ​ ​ Mexican ​ ​ Corporate, other ​ ​ ​ ​ Mexican ​ IMMSA ​ Peruvian ​ and ​ ​ ​ ​ Open-pit ​ Unit ​ Operations ​ eliminations ​ Consolidated Net sales outside of segments ​ $ 3,124.9 ​ $ 354.0 ​ $ 1,923.2 ​ $ ​ ​ $ 5,402.1 Intersegment sales ​ — ​ 55.6 ​ — ​ (55.6) ​ — Cost of sales (exclusive of depreciation, amortization and depletion) ​ 1,214.8 ​ 271.2 ​ 1,126.7 ​ (60.5) ​ 2,552.2 Selling, general and administrative ​ 41.4 ​ ​ 6.8 ​ ​ 26.9 ​ ​ 1.6 ​ 76.7 Depreciation, amortization and depletion ​ 269.5 ​ 33.6 ​ 171.3 ​ 20.8 ​ 495.2 Exploration ​ 1.5 ​ 3.6 ​ 11.7 ​ 3.5 ​ 20.3 Operating income ​ $ 1,597.7 ​ $ 94.4 ​ $ 586.6 ​ $ (21.0) ​ ​ 2,257.7 Less: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest, net ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (197.2) Other income (expense) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (13.1) Income taxes ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (803.6) Equity earnings of affiliate ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 9.9 Non-controlling interest ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (3.9) Net income attributable to SCC ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 1,249.8 Capital investment ​ $ 197.9 ​ $ 32.6 ​ $ 581.9 ​ $ 19.4 ​ $ 831.8 Property and mine development, net ​ $ 4,579.5 ​ $ 433.4 ​ $ 3,745.6 ​ $ 553.3 ​ $ 9,311.8 Total assets ​ $ 8,122.7 ​ $ 974.1 ​ $ 4,754.9 ​ $ 465.0 ​ $ 14,316.7 ​

SUBSEQUENT EVENTS_

SUBSEQUENT EVENTS:	9 Months Ended
	Sep. 30, 2019
SUBSEQUENT EVENTS:
SUBSEQUENT EVENTS:	NOTE 16 — SUBSEQUENT EVENTS: ​ Dividends ​ On October 17, 2019, the Board of Directors authorized a dividend of $0.40 per share payable on November 21, 2019 to shareholders of record at the close of business on November 7, 2019. ​ Tia Maria construction license ​ 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 to resolve on these complaints. The Mining Council temporarily suspended the construction permit on August 8, 2019 until a decision is reached on the complaints. On October 7, 2019, as part of the process, the Mining Council conducted a hearing on the complaints and the Company position. ​

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES: (Policies)	9 Months Ended
	Sep. 30, 2019
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:
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.
ADOPTION OF LEASES STANDARD	ADOPTION OF LEASES STANDARD ​ The Company has adopted FASB ASC 842, Leases, effective January 1, 2019, applying the transition approach which permits it to recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. Consequently, the financial statements for prior periods were not modified. At the date of adoption, the Company assessed that the adoption of the new leases standard resulted in the recognition of right of use assets and lease obligations of approximately $1,115.9 million, which was recorded in the Company’s balance sheet as of January 1, 2019. ​ During 2018, the Company developed an implementation plan with a cross-functional team, which performed a completeness assessment over the lease contracts of the Company, established new policies, procedures and internal controls related to the new standard. As result of its analysis, the Company has concluded that all of its existing lease contracts at January 1, 2019, have been classified as operating lease contracts. ​ Additionally, the Company has 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). The new standard had a material impact on the Company’s balance sheet, but did not have a material impact on its income statement and had no impact on cash flows.

SHORT-TERM INVESTMENTS_ (Tables

SHORT-TERM INVESTMENTS: (Tables)	9 Months Ended
	Sep. 30, 2019
SHORT-TERM INVESTMENTS:
Schedule of short-term investments	​ Short-term investments were as follows ($ in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ At September 30, ​ At December 31, ​ ​ ​ 2019 2018 ​ ​ Trading securities ​ $ 1.0 ​ $ 213.1 ​ ​ Weighted average interest rate ​ 1.9 % 2.2 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Available-for-sale ​ $ 0.7 ​ $ 0.7 ​ ​ Weighted average interest rate ​ 0.9 % 0.7 % ​ Total ​ $ 1.7 ​ $ 213.8 ​ ​
Summary of activity investments	The following table summarizes the activity of these investments by category (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended ​ Nine months ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2019 2018 2019 2018 ​ Trading: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest earned ​ $ (*) ​ $ 0.1 ​ $ 0.1 ​ $ 0.2 ​ ​ Unrealized gain (loss) at the end of the period ​ $ (*) ​ $ (0.2) ​ $ (*) ​ $ (0.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest earned ​ (*) ​ ​ (*) ​ (*) ​ ​ (*) ​ ​ Investment redeemed ​ $ — ​ $ 0.1 ​ $ — ​ $ 0.3 ​ ​ (*) Less than $0.1 million.

INVENTORIES_ (Tables)

INVENTORIES: (Tables)	9 Months Ended
	Sep. 30, 2019
INVENTORIES:
Schedule of inventories	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ At September 30, ​ At December 31, ​ (in millions) 2019 2018 ​ Inventory, current: ​ ​ ​ ​ ​ ​ ​ Metals at average cost: ​ ​ ​ ​ ​ ​ ​ Finished goods ​ $ 60.0 ​ $ 69.6 ​ Work-in-process ​ 276.4 ​ 256.8 ​ Ore stockpiles on leach pads ​ ​ 356.5 ​ ​ 328.0 ​ Supplies at average cost ​ 369.3 ​ 378.3 ​ Total current inventory ​ $ 1,062.2 ​ $ 1,032.7 ​ Inventory, long-term: ​ ​ ​ ​ ​ ​ ​ Ore stockpiles on leach pads ​ $ 1,224.9 ​ $ 1,177.4 ​

INCOME TAXES_ (Tables)

INCOME TAXES: (Tables)	9 Months Ended
	Sep. 30, 2019
INCOME TAXES:
Schedule of income tax provision and effective income tax rate	​ The income tax provision and the effective income tax rate for the nine months of 2019 and 2018 consisted of ($ in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2018 ​ Statutory income tax provision ​ $ 648.0 ​ $ 698.5 ​ GILTI Tax ​ ​ — ​ ​ 15.2 ​ Peruvian royalty ​ 8.6 ​ 6.7 ​ Mexican royalty ​ 47.6 ​ 60.9 ​ Peruvian special mining tax ​ 25.8 ​ 22.3 ​ Total income tax provision ​ $ 730.0 ​ $ 803.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ Effective income tax rate ​ ​ 38.2 % ​ 39.2 %

RELATED PARTY TRANSACTIONS_ (Ta

RELATED PARTY TRANSACTIONS: (Tables)	9 Months Ended
	Sep. 30, 2019
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 September 30, ​ At December 31, ​ ​ 2019 2018 ​ Related parties receivable current: ​ ​ ​ ​ ​ ​ ​ Grupo Mexico and affiliates: ​ ​ ​ ​ ​ ​ ​ Asarco LLC ​ $ 9.0 ​ $ 74.4 ​ Americas Mining Corporation (“AMC”) ​ ​ — ​ ​ 11.0 ​ AMMINCO Apoyo Administrativo, S.A. de C.V. (“AMMINCO”) ​ 0.1 ​ 0.2 ​ Compania Perforadora Mexico S.A.P.I. de C.V. and affiliates ​ 0.4 ​ 1.4 ​ Ferrocarril Mexicano, S.A. de C.V. ​ — ​ 0.1 ​ Grupo Mexico ​ 2.7 ​ 2.7 ​ Mexico Generadora de Energia S. de R.L. ("MGE") ​ ​ 9.1 ​ ​ 10.3 ​ Mexico Proyectos y Desarrollos, S.A. de C.V. and affiliates ​ ​ 0.5 ​ ​ 0.6 ​ Related to the controlling group: ​ ​ ​ ​ ​ ​ ​ Boutique Bowling de Mexico S.A. de C.V. ​ ​ 0.1 ​ ​ 0.3 ​ Mexico Transportes Aereos, S.A. de C.V. ("Mextransport") ​ ​ 0.3 ​ ​ 0.1 ​ Operadora de Cinemas S.A. de C.V. ​ ​ 0.1 ​ ​ 0.4 ​ ​ ​ $ 22.3 ​ $ 101.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ Related parties receivable non-current: ​ ​ ​ ​ ​ ​ ​ Grupo Mexico and affiliates: ​ ​ ​ ​ ​ ​ ​ Asarco LLC ​ $ 60.0 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ Related parties payable: ​ ​ ​ ​ ​ ​ ​ Grupo Mexico and affiliates: ​ ​ ​ ​ ​ ​ ​ Asarco LLC ​ $ 15.0 ​ $ 4.1 ​ AMMINCO ​ ​ 4.0 ​ ​ 8.0 ​ Eolica El Retiro, S.A.P.I. de C.V. ​ 0.3 ​ 1.0 ​ Ferrocarril Mexicano S.A. de C.V. ​ 4.8 ​ 6.4 ​ Grupo Mexico ​ 0.2 ​ 0.6 ​ MGE ​ ​ 34.9 ​ ​ 40.6 ​ Mexico Proyectos y Desarrollos S.A. de C.V. and affiliates ​ ​ 18.0 ​ ​ 14.4 ​ Related to the controlling group: ​ ​ ​ ​ ​ ​ ​ Boutique Bowling de Mexico S.A. de C.V. ​ 0.2 ​ 0.1 ​ Operadora de Cinemas S.A. de C.V. ​ ​ 0.1 ​ ​ 0.1 ​ ​ ​ $ 77.5 ​ $ 75.3 ​ ​
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 the nine months ended September 30, 2019 and 2018 (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2018 Purchase activity ​ ​ ​ ​ ​ ​ Asarco LLC ​ $ 32.2 ​ $ 30.0 AMMINCO ​ ​ 6.4 ​ ​ — Eolica El Retiro, S.A.P.I. de C.V. ​ 2.9 ​ 2.2 Ferrocarril Mexicano, S.A. de C.V. ​ 35.1 ​ 33.0 Grupo Mexico ​ ​ 7.9 ​ ​ 13.5 MGE ​ 147.3 ​ 144.4 Mexico Proyectos y Desarrollos S.A. de C.V. and affiliates ​ 56.4 ​ 63.1 Total purchases ​ $ 288.2 ​ $ 286.2 Sales activity ​ ​ ​ ​ ​ ​ Asarco LLC ​ $ 10.6 ​ $ 82.8 Ferrocarril Mexicano, S.A. de C.V. ​ 0.1 ​ — MGE ​ ​ 33.3 ​ ​ 52.3 Total sales ​ $ 44.0 ​ $ 135.1 ​
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 the nine months ended September 30, 2019 and 2018 (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2018 Purchase activity ​ ​ ​ ​ ​ ​ Boutique Bowling de Mexico S.A. de C.V. ​ $ 0.3 ​ $ 0.2 Mextransport ​ ​ 1.1 ​ ​ 1.1 Operadora de Cinemas S.A. de C.V. ​ ​ 0.1 ​ ​ 0.1 Total purchases ​ $ 1.5 ​ $ 1.4 ​ ​ ​ ​ ​ ​ ​ Sales activity ​ ​ ​ ​ ​ ​ Boutique Bowling de Mexico S.A. de C.V. ​ $ 0.1 ​ $ 0.2 Empresarios Industriales de Mexico, S.A. de C.V. ​ ​ 0.2 ​ ​ — Mextransport ​ ​ 1.3 ​ ​ 1.2 Operadora de Cinemas S.A. de C.V. ​ ​ 0.1 ​ ​ 0.1 Total sales ​ $ 1.7 ​ $ 1.5

LEASES_ (Tables)

LEASES: (Tables)	9 Months Ended
	Sep. 30, 2019
LEASES:
Schedule of the operating lease expense recognized	The operating lease expense recognized in the nine months ended September 30, 2019 was classified as follows (in millions): ​ ​ ​ ​ ​ Classification 2019 Cost of sales (exclusive of depreciation, amortization and depletion) $ 86.8 Selling, general and administrative ​ 0.1 Exploration ​ 0.1 Total lease expense $ 87.0
Schedule of Maturities of lease liabilities	​ ​ ​ ​ ​ ​ ​ Lease liabilities Year (in millions) 2019 $ 28.9 2020 ​ 115.4 2021 ​ 115.3 2022 ​ 112.2 2023 ​ 111.1 After 2023 ​ 929.2 Total lease payments $ 1,412.1 Less: interest on lease liabilities ​ (350.3) Present value of lease payments $ 1,061.8

ASSET RETIREMENT OBLIGATION_ (T

ASSET RETIREMENT OBLIGATION: (Tables)	9 Months Ended
	Sep. 30, 2019
ASSET RETIREMENT OBLIGATION:
Summary of asset retirement obligation activity	​ The following table summarizes the asset retirement obligation activity for the nine months ended September 30, 2019 and 2018 (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2018 Balance as of January 1 ​ $ 217.7 ​ $ 222.5 Changes in estimates ​ 25.2 ​ (15.6) Closure payments ​ (0.8) ​ — Accretion expense ​ 9.5 ​ 8.9 Balance as of September 30, ​ $ 251.6 ​ $ 215.8

BENEFIT PLANS_ (Tables)

BENEFIT PLANS: (Tables)	9 Months Ended
	Sep. 30, 2019
Post retirement defined benefit plans and defined contribution plan
Components of net periodic benefit costs
Schedule of the components of net periodic benefit costs	The components of net periodic benefit costs for the nine months ended September 30, 2019 and 2018 are as follows (in millions): ​ ​ ​ ​ ​ ​ ​ ​ (in millions) 2019 2018 Service cost ​ $ 0.8 ​ $ 0.8 Interest cost ​ 1.3 ​ 1.2 Expected return on plan assets ​ (2.6) ​ (2.7) Amortization of prior service cost / (credit) ​ 0.2 ​ 0.2 Amortization of net loss/(gain) ​ 0.1 ​ 0.1 Net periodic benefit cost ​ $ (0.2) ​ $ (0.4)
Post-retirement Health care plans
Components of net periodic benefit costs
Schedule of the components of net periodic benefit costs	​ The components of net periodic benefit cost for the nine months ended September 30, 2019 and 2018 are as follows (in millions): ​ ​ ​ ​ ​ ​ ​ ​ (in millions) 2019 2018 Interest cost ​ $ 0.7 ​ $ 0.7 Amortization of net loss (gain) ​ (0.2) ​ (0.2) Amortization of prior service cost/ (credit) ​ (*) ​ (*) Net periodic benefit cost ​ $ 0.5 ​ $ 0.5 (*) amount is lower than $0.1 million

COMMITMENTS AND CONTINGENCIES_

COMMITMENTS AND CONTINGENCIES: (Tables)	9 Months Ended
	Sep. 30, 2019
COMMITMENTS AND CONTINGENCIES:
Schedule of environmental capital investments	Environmental capital investments in the nine months ended September 30, 2019 and 2018 were as follows (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2018 Peruvian operations ​ $ 12.9 ​ $ 38.0 Mexican operations ​ 55.9 ​ 35.3 ​ ​ $ 68.8 ​ $ 73.3 ​

STOCKHOLDERS' EQUITY_ (Tables)

STOCKHOLDERS' EQUITY: (Tables)	9 Months Ended
	Sep. 30, 2019
STOCKHOLDERS' EQUITY:
Schedule of activity in treasury stock	​ Activity in treasury stock in the nine-month period ended September 30, 2019 and 2018 is as follows (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2018 Southern Copper common shares ​ ​ ​ ​ ​ ​ Balance as of January 1, ​ $ 2,768.3 ​ $ 2,768.7 Used for corporate purposes ​ (0.4) ​ (0.4) Balance as of September 30, ​ 2,767.9 ​ 2,768.3 ​ ​ ​ ​ ​ ​ ​ Parent Company (Grupo Mexico) common shares ​ ​ ​ ​ ​ ​ Balance as of January 1, ​ 251.3 ​ 232.4 Other activity, including dividend, interest and foreign currency transaction effect ​ 20.7 ​ 17.3 Balance as of September 30, ​ 272.0 ​ 249.7 Treasury stock balance as of September 30, ​ $ 3,039.9 ​ $ 3,018.0
Schedule of common shares	​ ​ ​ ​ ​ ​ ​ 2019 2018 Southern Copper common shares ​ ​ ​ ​ Directors’ Stock Award Plan ​ 14,400 ​ 16,000 ​ ​ ​ ​ ​ Parent Company (Grupo Mexico) common shares ​ ​ ​ ​ Employee stock purchase plan (shares in millions) ​ 0.4 ​ 1.3
Summary of non-controlling interest activity	The following table presents the non-controlling interest activity for the nine months ended September 30, 2019 and 2018 (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2018 Balance as of January 1, $ 45.4 $ 41.7 Net earnings ​ 4.7 ​ 3.9 Dividend paid ​ (1.1) ​ (1.2) Balance as of September 30, $ 49.0 $ 44.4
Employee Stock Purchase 2015 Plan
STOCKHOLDERS' EQUITY:
Schedule of stock based compensation expense and unrecognized compensation expense	​ The stock based compensation expense for the nine months 2019 and 2018 and the unrecognized compensation expense under this plan were as follows (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2018 Stock based compensation expense ​ $ 0.4 ​ $ 0.4 Unrecognized compensation expense ​ $ 2.2 ​ $ 2.8 ​
Schedule of stock award activity	​ ​ ​ ​ ​ ​ ​ ​ ​ Unit Weighted Average ​ ​ Shares ​ Grant Date Fair Value Outstanding shares at January 1, 2019 1,840,336 ​ $ 2.63 Granted — ​ — Exercised (437,386) ​ $ 2.63 Forfeited — ​ — Outstanding shares at September 30, 2019 1,402,950 ​ $ 2.63 Outstanding shares at January 1, 2018 2,293,120 ​ $ 2.63 Granted — ​ — Exercised (306,817) ​ $ 2.63 Forfeited — ​ — Outstanding shares at September 30, 2018 1,986,303 ​ $ 2.63 ​
Employee Stock Purchase 2018 Plan
STOCKHOLDERS' EQUITY:
Schedule of stock based compensation expense and unrecognized compensation expense	​ The stock based compensation expense for the nine months ended September 30, 2019 and the unrecognized compensation expense under this plan were as follows (in millions): ​ ​ ​ ​ ​ ​ 2019 Stock based compensation expense ​ $ 0.5 Unrecognized compensation expense ​ $ 4.7 ​ ​ The following table presents the stock award activity of this plan for the nine months ended September 30, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unit Weighted Average ​ Shares Grant Date Fair Value Outstanding shares at January 1, 2019 2,782,424 1.86 Granted 1,238,169 1.86 Exercised — — Forfeited — ​ — Outstanding shares at September 30, 2019 4,020,593 ​ 1.86 ​
Schedule of stock award activity	​

FAIR VALUE MEASUREMENT_ (Tables

FAIR VALUE MEASUREMENT: (Tables)	9 Months Ended
	Sep. 30, 2019
FAIR VALUE MEASUREMENT:
Schedule of carrying amount and estimated fair values of the Company's financial instruments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ At September 30, 2019 ​ At December 31, 2018 ​ Carrying Value Fair Value Carrying Value Fair Value Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Long-term debt level 1 ​ ​ 6,190.1 ​ ​ 7,452.7 ​ ​ 5,210.7 ​ ​ 5,540.0 Long-term debt level 2 ​ ​ 750.0 ​ ​ 778.0 ​ ​ 749.4 ​ ​ 761.7 Total long-term debt ​ $ 6,940.1 ​ $ 8,230.7 ​ $ 5,960.1 ​ $ 6,301.7
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 follows as of September 30, 2019 and December 31, 2018 (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value at Measurement Date Using: ​ ​ ​ ​ ​ Significant ​ ​ ​ ​ Fair Value ​ Quoted prices in ​ other ​ Significant ​ ​ as of ​ active markets for ​ observable ​ unobservable ​ ​ September 30, ​ identical assets ​ inputs ​ inputs Description ​ 2019 ​ (Level 1) ​ (Level 2) ​ (Level 3) Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Short term investment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ — ​ $ 1.0 ​ $ 1.0 ​ $ — ​ $ — — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate bonds ​ — ​ ​ — ​ ​ — ​ ​ — Asset backed securities ​ 0.4 ​ ​ — ​ ​ 0.4 ​ ​ — Mortgage backed securities ​ 0.3 ​ ​ — ​ ​ 0.3 ​ ​ — Accounts receivable: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ — — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Provisionally priced sales: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Copper ​ 544.7 ​ 544.7 ​ ​ — ​ ​ — Molybdenum ​ 166.6 ​ 166.6 ​ — ​ ​ — Total ​ $ 713.0 ​ $ 712.3 ​ $ 0.7 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 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 ​ 2018 ​ (Level 1) ​ (Level 2) ​ (Level 3) Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Short term investment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ — ​ $ 213.1 ​ $ 213.1 ​ $ — ​ $ — — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate bonds ​ — ​ ​ — ​ ​ — ​ ​ — Asset backed securities ​ 0.4 ​ ​ — ​ 0.4 ​ ​ — Mortgage backed securities ​ 0.3 ​ ​ — ​ ​ 0.3 ​ ​ — Accounts receivable: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Provisionally priced sales: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Copper ​ 274.3 ​ 274.3 ​ ​ — ​ ​ — Molybdenum ​ 107.4 ​ 107.4 ​ — ​ ​ — Total ​ $ 595.5 ​ $ 594.8 ​ $ 0.7 ​ $ —

REVENUE_ (Tables)

REVENUE: (Tables)	9 Months Ended
	Sep. 30, 2019
REVENUE:
Summary of company's sales by geographic wise and segment wise	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2019 ​ ​ ​ ​ Mexican ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexican ​ IMMSA ​ Peruvian ​ Corporate & ​ ​ ​ ​ Open-Pit Unit Operations Elimination Consolidated The Americas: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexico ​ $ 338.3 ​ $ 81.8 ​ $ — ​ $ (18.6) ​ $ 401.5 United States ​ 280.4 ​ 3.1 ​ 58.7 ​ — ​ 342.2 Peru ​ — ​ — ​ 75.2 ​ — ​ 75.2 Brazil ​ — ​ 1.0 ​ 48.7 ​ — ​ 49.7 Chile ​ 0.1 ​ — ​ 64.4 ​ — ​ 64.5 Other American countries ​ 10.1 ​ 0.7 ​ 0.4 ​ — ​ 11.2 Europe: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Switzerland ​ 171.1 ​ 11.3 ​ 81.5 ​ — ​ 263.9 Italy ​ 5.7 ​ 2.0 ​ 54.6 ​ — ​ 62.3 Spain ​ 46.7 ​ — ​ — ​ — ​ 46.7 Other European countries ​ 24.8 ​ 4.4 ​ 38.0 ​ — ​ 67.2 Asia: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Singapore ​ 68.0 ​ 2.3 ​ 212.8 ​ — ​ 283.1 Japan ​ 21.3 ​ — ​ 106.6 ​ — ​ 127.9 Other Asian countries ​ 15.9 ​ 0.1 ​ 48.1 ​ — ​ 64.1 Total ​ $ 982.4 ​ $ 106.7 ​ $ 789.0 ​ $ (18.6) ​ $ 1,859.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2018 ​ ​ ​ ​ ​ Mexican ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexican ​ IMMSA ​ Peruvian ​ Corporate & ​ ​ ​ ​ Open-Pit Unit Operations Elimination Consolidated The Americas: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexico ​ $ 329.3 ​ $ 86.4 ​ $ — ​ $ (17.2) ​ $ 398.5 United States ​ 263.1 ​ 0.5 ​ 40.8 ​ ​ — ​ ​ 304.4 Peru ​ — ​ — ​ 92.6 ​ ​ — ​ ​ 92.6 Brazil ​ — ​ 6.6 ​ 55.9 ​ ​ — ​ ​ 62.5 Chile ​ — ​ — ​ 42.4 ​ ​ — ​ ​ 42.4 Other American countries ​ 15.2 ​ 0.5 ​ — ​ ​ — ​ ​ 15.7 Europe: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Switzerland ​ ​ 141.4 ​ ​ 6.8 ​ ​ 31.4 ​ ​ — ​ ​ 179.6 Italy ​ ​ 5.1 ​ ​ 3.4 ​ ​ 64.3 ​ ​ — ​ ​ 72.8 Spain ​ ​ 42.0 ​ ​ — ​ ​ — ​ ​ — ​ ​ 42.0 Other European countries ​ ​ 74.0 ​ ​ 2.9 ​ ​ 24.3 ​ ​ — ​ ​ 101.2 Asia: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Singapore ​ ​ 104.9 ​ ​ — ​ ​ 164.1 ​ ​ — ​ ​ 269.0 Japan ​ ​ (4.7) ​ ​ — ​ ​ 114.0 ​ ​ — ​ ​ 109.3 Other Asian countries ​ ​ 24.8 ​ ​ 0.2 ​ ​ 8.7 ​ ​ — ​ ​ 33.7 Total ​ $ 995.1 ​ $ 107.3 ​ $ 638.5 ​ $ (17.2) ​ $ 1,723.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2019 ​ ​ ​ ​ Mexican ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexican ​ IMMSA ​ Peruvian ​ Corporate & ​ ​ ​ ​ Open-Pit Unit Operations Elimination Consolidated The Americas: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexico ​ $ 1,002.5 ​ $ 261.3 ​ $ — ​ $ (63.9) ​ $ 1,199.9 United States ​ 817.3 ​ 6.2 ​ 87.0 ​ — ​ 910.5 Peru ​ 1.6 ​ — ​ 254.0 ​ — ​ 255.6 Brazil ​ — ​ 13.3 ​ 141.6 ​ — ​ 154.9 Chile ​ 1.3 ​ — ​ 143.6 ​ — ​ 144.9 Other American countries ​ 34.1 ​ 2.0 ​ 3.1 ​ — ​ 39.2 Europe: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Switzerland ​ 579.4 ​ 28.4 ​ 264.9 ​ — ​ 872.7 Italy ​ 42.7 ​ 10.3 ​ 165.6 ​ — ​ 218.6 Spain ​ 139.0 ​ — ​ — ​ — ​ 139.0 Other European countries ​ 70.3 ​ 19.2 ​ 159.0 ​ — ​ 248.5 Asia: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Singapore ​ 198.5 ​ 8.7 ​ 460.6 ​ — ​ 667.8 Japan ​ 37.3 ​ — ​ 350.6 ​ — ​ 387.9 Other Asian countries ​ 85.1 ​ 0.7 ​ 105.7 ​ — ​ 191.5 Total ​ $ 3,009.1 ​ $ 350.1 ​ $ 2,135.7 ​ $ (63.9) ​ $ 5,431.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2018 ​ ​ ​ ​ ​ Mexican ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexican ​ IMMSA ​ Peruvian ​ Corporate & ​ ​ ​ ​ Open-Pit Unit Operations Elimination Consolidated The Americas: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexico ​ $ 1,026.2 ​ $ 307.0 ​ $ — ​ $ (55.6) ​ $ 1,277.6 United States ​ 782.4 ​ 6.1 ​ 139.1 ​ ​ — ​ ​ 927.6 Peru ​ — ​ — ​ 292.7 ​ ​ — ​ ​ 292.7 Brazil ​ — ​ 28.8 ​ 183.2 ​ ​ — ​ ​ 212.0 Chile ​ — ​ — ​ 102.1 ​ ​ — ​ ​ 102.1 Other American countries ​ 41.6 ​ 2.9 ​ 1.2 ​ ​ — ​ ​ 45.7 Europe: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Switzerland ​ ​ 340.4 ​ ​ 33.9 ​ ​ 105.8 ​ ​ — ​ ​ 480.1 Italy ​ ​ 18.2 ​ ​ 16.8 ​ ​ 224.6 ​ ​ — ​ ​ 259.6 Spain ​ ​ 130.7 ​ ​ — ​ ​ — ​ ​ — ​ ​ 130.7 Other European countries ​ ​ 195.7 ​ ​ 13.4 ​ ​ 72.4 ​ ​ — ​ ​ 281.5 Asia: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Singapore ​ ​ 389.0 ​ ​ — ​ ​ 443.1 ​ ​ — ​ ​ 832.1 Japan ​ ​ 68.7 ​ ​ — ​ ​ 333.2 ​ ​ — ​ ​ 401.9 Other Asian countries ​ ​ 132.0 ​ ​ 0.7 ​ ​ 25.8 ​ ​ — ​ ​ 158.5 Total ​ $ 3,124.9 ​ $ 409.6 ​ $ 1,923.2 ​ $ (55.6) ​ $ 5,402.1 ​ The following table presents information regarding the sales value by reporting segment of the Company’s significant products for the three and nine months ended September 30, 2019 and 2018 (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2019 ​ ​ ​ Mexican ​ ​ ​ ​ ​ ​ ​ ​ Mexican IMMSA Peruvian Corporate, Other & Total ​ ​ Open-pit ​ Unit ​ Operations ​ Eliminations ​ Consolidated Copper ​ $ 809.6 ​ $ 11.5 ​ $ 667.3 ​ $ (11.0) ​ $ 1,477.4 Molybdenum ​ 91.2 ​ — ​ 65.3 ​ — ​ 156.5 Silver ​ 49.8 ​ 24.7 ​ 23.1 ​ (9.0) ​ 88.6 Zinc ​ — ​ 54.6 ​ — ​ 2.6 ​ 57.2 Other ​ 31.8 ​ 15.9 ​ 33.3 ​ (1.2) ​ 79.8 Total ​ $ 982.4 ​ $ 106.7 ​ $ 789.0 ​ $ (18.6) ​ $ 1,859.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2018 ​ ​ ​ Mexican ​ ​ ​ ​ ​ ​ ​ ​ Mexican IMMSA Peruvian Corporate, Other & Total ​ ​ Open-pit ​ Unit ​ Operations ​ Eliminations ​ Consolidated Copper ​ $ 840.8 ​ $ 9.9 ​ $ 550.8 ​ $ (10.0) ​ $ 1,391.5 Molybdenum ​ 89.2 ​ — ​ 48.4 ​ — ​ 137.6 Zinc ​ — ​ 63.2 ​ — ​ — ​ 63.2 Silver ​ 42.5 ​ 19.0 ​ 16.8 ​ (6.6) ​ 71.7 Other ​ 22.6 ​ 15.2 ​ 22.5 ​ (0.6) ​ 59.7 Total ​ $ 995.1 ​ $ 107.3 ​ $ 638.5 ​ $ (17.2) ​ $ 1,723.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2019 ​ ​ ​ Mexican ​ ​ ​ ​ ​ ​ ​ ​ Mexican IMMSA Peruvian Corporate, Other & Total ​ ​ Open-pit ​ Unit ​ Operations ​ Eliminations ​ Consolidated Copper ​ $ 2,504.9 ​ $ 34.5 ​ $ 1,840.7 ​ $ (38.2) ​ $ 4,341.9 Molybdenum ​ 274.8 ​ — ​ 154.6 ​ — ​ 429.4 Silver ​ 137.6 ​ 59.1 ​ 58.7 ​ (21.3) ​ 234.1 Zinc ​ — ​ 211.3 ​ — ​ (1.6) ​ 209.7 Other ​ 91.8 ​ 45.2 ​ 81.7 ​ (2.8) ​ 215.9 Total ​ $ 3,009.1 ​ $ 350.1 ​ $ 2,135.7 ​ $ (63.9) ​ $ 5,431.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2018 ​ ​ ​ Mexican ​ ​ ​ ​ ​ ​ ​ ​ Mexican IMMSA Peruvian Corporate, Other & Total ​ ​ Open-pit ​ Unit ​ Operations ​ Eliminations ​ Consolidated Copper ​ $ 2,661.9 ​ $ 37.0 ​ $ 1,686.7 ​ $ (32.2) ​ $ 4,353.4 Molybdenum ​ 254.2 ​ — ​ 124.3 ​ — ​ 378.5 Zinc ​ — ​ 253.0 ​ — ​ (0.1) ​ 252.9 Silver ​ 133.2 ​ 63.4 ​ 50.6 ​ (21.2) ​ 226.0 Other ​ 75.6 ​ 56.2 ​ 61.6 ​ (2.1) ​ 191.3 Total ​ $ 3,124.9 ​ $ 409.6 ​ $ 1,923.2 ​ $ (55.6) ​ $ 5,402.1
Schedule of opening and closing balances of receivables by reporting segment	The opening and closing balances of receivables by reporting segment of the Company were as follows (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexican ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mexican IMMSA Peruvian Corporate & ​ ​ ​ ​ Open-Pit ​ Unit ​ Operations ​ Elimination ​ Consolidated ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of September 30, 2019: ​ ​ ​ ​ ​ Trade receivables ​ $ 430.1 ​ $ 41.8 ​ $ 370.1 ​ $ — ​ $ 842.0 Related parties, current ​ 14.1 ​ — ​ — ​ 8.2 ​ 22.3 Related parties, non-current ​ ​ 60.0 ​ ​ — ​ ​ — ​ ​ — ​ ​ 60.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2018: ​ ​ ​ ​ ​ Trade receivables ​ $ 505.9 ​ $ 50.5 ​ $ 266.0 ​ $ — ​ $ 822.4 Related parties ​ 81.6 ​ — ​ — ​ 19.9 ​ 101.5
Schedule long term contracts by products	As of September 30, 2019, the Company has long-term contracts with promises to deliver the following products: ​ ​ ​ ​ Copper concentrates (in tons) 1,090,000 Copper cathodes (in tons) ​ 48,000 Molybdenum concentrates (in tons) 24,446 Sulfuric acid (in tons) 331,620 ​
Schedule of provisionally priced copper and molybdenum sales outstanding	Following are the provisionally priced copper and molybdenum sales outstanding at September 30, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ Sales volume Priced at ​ ​ ​ (million lbs.) ​ (per pound) ​ Month of settlement Copper ​ 210.4 ​ 2.59 ​ October 2019 through February 2020 Molybdenum ​ 14.1 ​ 11.78 ​ October through December 2019

SEGMENT AND RELATED INFORMATI_2

SEGMENT AND RELATED INFORMATION: (Tables)	9 Months Ended
	Sep. 30, 2019
SEGMENT AND RELATED INFORMATION:
Schedule of financial information relating to Company's segments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2019 ​ ​ (in millions) ​ ​ Mexican ​ ​ Corporate, other ​ ​ ​ ​ Mexican ​ IMMSA ​ Peruvian ​ and ​ ​ ​ ​ ​ Open-pit ​ Unit ​ Operations ​ eliminations ​ Consolidated Net sales outside of segments ​ $ 982.4 ​ $ 88.1 ​ $ 789.0 ​ $ — ​ $ 1,859.5 Intersegment sales ​ — ​ ​ 18.6 ​ — ​ (18.6) ​ — Cost of sales (exclusive of depreciation, amortization and depletion) ​ 390.2 ​ 80.7 ​ 452.5 ​ (16.9) ​ 906.5 Selling, general and administrative ​ 19.4 ​ 2.0 ​ 9.4 ​ 1.2 ​ 32.0 Depreciation, amortization and depletion ​ 91.1 ​ 13.7 ​ 88.4 ​ 7.1 ​ 200.3 Exploration ​ 0.5 ​ 2.3 ​ 1.9 ​ 2.2 ​ 6.9 Operating income ​ $ 481.2 ​ $ 8.0 ​ $ 236.8 ​ $ (12.2) ​ ​ 713.8 Less: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest, net ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (78.7) Other income (expense) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (6.3) Income taxes ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (241.0) Equity earnings of affiliate ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 3.5 Non-controlling interest ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1.7) Net income attributable to SCC ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 389.6 Capital investment ​ $ 59.4 ​ $ 32.1 ​ $ 88.8 ​ $ 2.4 ​ $ 182.7 Property and mine development, net ​ $ 4,691.2 ​ $ 487.6 ​ $ 3,878.7 ​ $ 337.8 ​ $ 9,395.3 Total assets ​ $ 8,093.3 ​ $ 839.3 ​ $ 5,114.6 ​ $ 2,447.2 ​ $ 16,494.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2018 ​ ​ (in millions) ​ ​ Mexican ​ ​ Corporate, other ​ ​ ​ ​ Mexican ​ IMMSA ​ Peruvian ​ and ​ ​ ​ ​ Open-pit ​ Unit ​ Operations ​ eliminations ​ Consolidated Net sales outside of segments ​ $ 995.1 ​ $ 90.1 ​ $ 638.5 ​ $ — ​ $ 1,723.7 Intersegment sales ​ — ​ 17.2 ​ — ​ (17.2) ​ — Cost of sales (exclusive of depreciation, amortization and depletion) ​ 398.8 ​ 74.7 ​ 369.3 ​ (18.8) ​ 824.0 Selling, general and administrative ​ 15.8 ​ 1.9 ​ 8.5 ​ 0.2 ​ 26.4 Depreciation, amortization and depletion ​ 95.1 ​ 11.5 ​ 61.6 ​ 2.4 ​ 170.6 Exploration ​ 0.4 ​ 1.1 ​ 2.2 ​ 2.3 ​ 6.0 Operating income ​ $ 485.0 ​ $ 18.1 ​ $ 196.9 ​ $ (3.3) ​ ​ 696.7 Less: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest, net ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (64.8) Other income (expense) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (7.6) Income taxes ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (257.9) Equity earnings of affiliate ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 4.3 Non-controlling interest ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1.3) Net income attributable to SCC ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 369.4 Capital investment ​ $ 53.7 ​ $ 10.2 ​ $ 217.7 ​ $ 0.7 ​ $ 282.3 Property and mine development, net ​ $ 4,579.5 ​ $ 433.4 ​ $ 3,745.6 ​ $ 553.3 ​ $ 9,311.8 Total assets ​ $ 8,122.7 ​ $ 974.1 ​ $ 4,754.9 ​ $ 465.0 ​ $ 14,316.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2019 ​ ​ (in millions) ​ ​ Mexican ​ ​ Corporate, other ​ ​ ​ ​ Mexican ​ IMMSA ​ Peruvian ​ and ​ ​ ​ ​ ​ Open-pit ​ Unit ​ Operations ​ eliminations ​ Consolidated Net sales outside of segments ​ $ 3,009.1 ​ $ 286.2 ​ $ 2,135.7 ​ $ — ​ $ 5,431.0 Intersegment sales ​ — ​ 63.9 ​ — ​ (63.9) ​ — Cost of sales (exclusive of depreciation, amortization and depletion) ​ 1,194.9 ​ 285.3 ​ 1,208.0 ​ (70.3) ​ 2,617.9 Selling, general and administrative ​ 51.4 ​ 6.0 ​ 28.2 ​ 5.8 ​ 91.4 Depreciation, amortization and depletion ​ 263.9 ​ 39.9 ​ 247.8 ​ 29.0 ​ 580.6 Exploration ​ 1.4 ​ 7.0 ​ 9.0 ​ 2.5 ​ 19.9 Operating income ​ $ 1,497.5 ​ $ 11.9 ​ $ 642.7 ​ $ (30.9) ​ ​ 2,121.2 Less: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest, net ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (232.5) Other income (expense) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 22.0 Income taxes ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (730.0) Equity earnings of affiliate ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 4.2 Non-controlling interest ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (4.7) Net income attributable to SCC ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 1,180.2 Capital investment ​ $ 180.5 ​ $ 79.6 ​ $ 271.5 ​ $ 4.5 ​ $ 536.1 Property and mine development, net ​ $ 4,691.2 ​ $ 487.6 ​ $ 3,878.7 ​ $ 337.8 ​ $ 9,395.3 Total assets ​ $ 8,093.3 ​ $ 839.3 ​ $ 5,114.6 ​ $ 2,447.2 ​ $ 16,494.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2018 ​ ​ (in millions) ​ ​ Mexican ​ ​ Corporate, other ​ ​ ​ ​ Mexican ​ IMMSA ​ Peruvian ​ and ​ ​ ​ ​ Open-pit ​ Unit ​ Operations ​ eliminations ​ Consolidated Net sales outside of segments ​ $ 3,124.9 ​ $ 354.0 ​ $ 1,923.2 ​ $ ​ ​ $ 5,402.1 Intersegment sales ​ — ​ 55.6 ​ — ​ (55.6) ​ — Cost of sales (exclusive of depreciation, amortization and depletion) ​ 1,214.8 ​ 271.2 ​ 1,126.7 ​ (60.5) ​ 2,552.2 Selling, general and administrative ​ 41.4 ​ ​ 6.8 ​ ​ 26.9 ​ ​ 1.6 ​ 76.7 Depreciation, amortization and depletion ​ 269.5 ​ 33.6 ​ 171.3 ​ 20.8 ​ 495.2 Exploration ​ 1.5 ​ 3.6 ​ 11.7 ​ 3.5 ​ 20.3 Operating income ​ $ 1,597.7 ​ $ 94.4 ​ $ 586.6 ​ $ (21.0) ​ ​ 2,257.7 Less: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest, net ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (197.2) Other income (expense) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (13.1) Income taxes ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (803.6) Equity earnings of affiliate ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 9.9 Non-controlling interest ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (3.9) Net income attributable to SCC ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 1,249.8 Capital investment ​ $ 197.9 ​ $ 32.6 ​ $ 581.9 ​ $ 19.4 ​ $ 831.8 Property and mine development, net ​ $ 4,579.5 ​ $ 433.4 ​ $ 3,745.6 ​ $ 553.3 ​ $ 9,311.8 Total assets ​ $ 8,122.7 ​ $ 974.1 ​ $ 4,754.9 ​ $ 465.0 ​ $ 14,316.7

DESCRIPTION OF THE BUSINESS_ (D

DESCRIPTION OF THE BUSINESS: (Details)	Sep. 30, 2019
DESCRIPTION OF THE BUSINESS:
Percentage of ownership interest held by the parent company	88.90%

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES: (Details) - USD ($) $ in Millions	Sep. 30, 2019	Jan. 01, 2019
Segment Reporting Information [Line Items]
Right-of-use assets	$ 1,061.7
Lease obligation	$ 1,061.8
ASU 2016-02 | Restatement
Segment Reporting Information [Line Items]
Right-of-use assets		$ 1,115.9
Lease obligation		$ 1,115.9

SHORT-TERM INVESTMENTS_ (Detail

SHORT-TERM INVESTMENTS: (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Short-term investment:
Trading securities	$ 1		$ 1		$ 213.1
Weighted average interest rate (as a percent)			1.90%		2.20%
Available-for-sale	0.7		$ 0.7		$ 0.7
Weighted average interest rate (as a percent)			0.90%		0.70%
Total	1.7		$ 1.7		$ 213.8
Trading:
Interest earned		$ 0.1	0.1	$ 0.2
Unrealized gain (loss) at the end of the period		(0.2)		(0.2)
Available-for-sale:
Interest earned	5.1	4.4	13.1	9.8
Investment redeemed		0.1		0.3
Maximum
Available-for-sale:
Interest earned	$ 0.1	$ 0.1	$ 0.1	$ 0.1

INVENTORIES_ (Details)

INVENTORIES: (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Metals at average cost:
Finished goods	$ 60		$ 69.6
Work-in-process	276.4		256.8
Ore stockpiles on leach pads	356.5		328
Supplies at average cost	369.3		378.3
Total current inventory	1,062.2		1,032.7
Inventory, non-current:
Ore stockpiles on leach pads	1,224.9		$ 1,177.4
Total leaching costs capitalized as non-current inventory of ore stockpiles	362	$ 393.6
Long-term leaching inventories recognized as cost of sales	$ 286.1	$ 240

INCOME TAXES_ (Details)

INCOME TAXES: (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Income Taxes
Statutory income tax provision			$ 648	$ 698.5
GILTI tax				15.2
Peruvian royalty			8.6	6.7
Mexican royalty			47.6	60.9
Peruvian special mining tax			25.8	22.3
Total income tax provision	$ 241	$ 257.9	$ 730	$ 803.6
Effective income tax rate (as a percent)			38.20%	39.20%
Unrecognized tax benefits	69.5		$ 69.5		$ 214.5
Peru
Income Taxes
Peruvian royalty			8.6	$ 6.7
Royalty charges			31.7	24.2
Accrued special mining tax			25.8	22.3
Unrecognized tax benefits	0		0
Mexico
Income Taxes
Mexican royalty			47.6	$ 60.9
Unrecognized tax benefits	$ 0		$ 0

INCOME TAXES_ - Other (Details)

INCOME TAXES: - Other (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018
Income Taxes
Peruvian special mining tax		$ 25.8	$ 22.3
Changes in unrecognized tax benefits
Unrecognized tax benefits, opening balance		214.5
Decreases related to settlements with taxing authorities	$ 145
Unrecognized tax benefits, ending balance	69.5	69.5
Peru
Income Taxes
Royalty charges		31.7	$ 24.2
Changes in unrecognized tax benefits
Unrecognized tax benefits, ending balance	0	0
Mexico
Changes in unrecognized tax benefits
Unrecognized tax benefits, ending balance	$ 0	$ 0

RELATED PARTY TRANSACTIONS_ (De

RELATED PARTY TRANSACTIONS: (Details) $ in Millions	Aug. 04, 2014item	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Dec. 31, 2012itemMW	Dec. 31, 2018USD ($)
RELATED PARTY TRANSACTIONS:
Related parties receivable current:		$ 22.3			$ 101.5
Related parties receivable non-current:		60
Related parties payable:		77.5			75.3
Total purchases		1.5	$ 1.4
Total sales		1.7	1.5
Grupo Mexico and affiliates
RELATED PARTY TRANSACTIONS:
Total purchases		288.2	286.2
Total sales		44	135.1
Asarco LLC
RELATED PARTY TRANSACTIONS:
Related parties receivable current:		9			74.4
Related parties receivable non-current:		60
Related parties payable:		15			4.1
Total purchases		32.2	30
Total sales		10.6	82.8
Accounts Payable		62
Making quarterly payments		0.5
Asarco LLC | Other Noncurrent Assets [Member]
RELATED PARTY TRANSACTIONS:
Due from related parties, non-current		60
Asarco LLC | Other Current Assets [Member]
RELATED PARTY TRANSACTIONS:
Related parties receivable current:		$ 2
Asarco LLC | London Interbank Offered Rate (LIBOR) [Member]
RELATED PARTY TRANSACTIONS:
Debt Instrument, Basis Spread on Variable Rate		2.00%
Debt Instrument, Interest Rate, Effective Percentage		4.08513%
AMMINCO
RELATED PARTY TRANSACTIONS:
Related parties receivable current:		$ 0.1			0.2
Related parties payable:		4			8
Total purchases		6.4
AMC
RELATED PARTY TRANSACTIONS:
Related parties receivable current:					11
Compania Perforadora Mexico, S.A.P.I. de C.V. and affiliates
RELATED PARTY TRANSACTIONS:
Related parties receivable current:		0.4			1.4
Eolica El Retiro, S.A.P.I. de C.V.
RELATED PARTY TRANSACTIONS:
Related parties payable:		0.3			1
Total purchases		2.9	2.2
Number of wind turbines | item	37
Percentage of supply to third-party energy users	25.40%
Ferrocarril Mexicano, S.A. de C.V.
RELATED PARTY TRANSACTIONS:
Related parties receivable current:					0.1
Related parties payable:		4.8			6.4
Total purchases		35.1	33
Total sales		0.1
Grupo Mexico
RELATED PARTY TRANSACTIONS:
Related parties receivable current:		2.7			2.7
Related parties payable:		0.2			0.6
Total purchases		7.9	13.5
Donations		8.9
Mexico Generadora de Energia, S. de R.L. ("MGE")
RELATED PARTY TRANSACTIONS:
Related parties receivable current:		9.1			10.3
Related parties payable:		34.9			40.6
Total purchases		147.3	144.4
Total sales		33.3	$ 52.3
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			22.00%	6.20%
Mexico Proyectos y Desarrollos, S.A. de C.V. and affiliates ("MPD")
RELATED PARTY TRANSACTIONS:
Related parties receivable current:		0.5			0.6
Related parties payable:		18			14.4
Mexico Proyectos y Desarrollos SA de CV and affiliates
RELATED PARTY TRANSACTIONS:
Total purchases		$ 56.4	$ 63.1
Apu Coropuna S.R.L.
RELATED PARTY TRANSACTIONS:
Ownership percentage		30.00%
Boutique Bowling de Mexico, S.A. de C.V.
RELATED PARTY TRANSACTIONS:
Related parties receivable current:		$ 0.1			0.3
Related parties payable:		0.2			0.1
Total purchases		0.3	0.2
Total sales		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:		0.3			0.1
Total purchases		1.1	1.1
Total sales		1.3	1.2
Operadora de Cinemas S.A. de C.V.
RELATED PARTY TRANSACTIONS:
Related parties receivable current:		0.1			0.4
Related parties payable:		0.1			$ 0.1
Total purchases		0.1	0.1
Total sales		$ 0.1	$ 0.1
Equity investment in affiliate
RELATED PARTY TRANSACTIONS:
Ownership percentage		44.20%

FINANCING_ (Details)

FINANCING: (Details) - 4.5 Senior Unsecured Notes Due 2050 - Minera Mexico S.A. de C.V. Notes $ in Millions	Sep. 26, 2019USD ($)
FINANCING
Face amount	$ 1,000
Debt discount	$ 12.7
Interest rate (as a percent)	4.50%

LEASES_ (Details)

LEASES: (Details)	9 Months Ended
	Sep. 30, 2019USD ($)
Leases
The weighted average remaining lease term	9 years
The weighted average discount rate	3.65%
Total lease expense	$ 87,000,000
Short term lease costs	300,000
Maturities of lease liabilities
2019	28,900,000
2020	115,400,000
2021	115,300,000
2022	112,200,000
2023	111,100,000
After 2023	929,200,000
Total lease payments	1,412,100,000
Less: interest on lease liabilities	(350,300,000)
Lease liabilities	1,061,800,000
Cost of sales (exclusive of depreciation, amortization and depletion)
Leases
Total lease expense	86,800,000
Selling, general and administrative
Leases
Total lease expense	100,000
Exploration
Leases
Total lease expense	$ 100,000
Minimum
Leases
Remaining lease terms	2 years
Maximum
Leases
Underlying asset value	$ 10,000
Total nominal contract value	$ 100,000
Remaining lease terms	13 years

ASSET RETIREMENT OBLIGATION_ (D

ASSET RETIREMENT OBLIGATION: (Details) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Sep. 30, 2019USD ($)item	Sep. 30, 2018USD ($)
Asset retirement obligation activity
Balance at the beginning of the year			$ 217.7	$ 222.5
Changes in estimates			25.2	(15.6)
Closure Payments			(0.8)
Accretion expense			9.5	8.9
Balance at the end of the year			$ 251.6	$ 215.8
Peru
ASSET RETIREMENT OBLIGATION:
Period after which successive reviews are required by the law (in years)			5 years
Accepted value of the Lima office complex and warehouse			$ 45.3
Cumulative guarantee amount			$ 37.8
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		$ (10.4)

BENEFIT PLANS_ (Details)

BENEFIT PLANS: (Details) $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2019USD ($)plan	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Benefit plans
Number of noncontributory defined benefit pension plans | plan	2
Maximum
Defined benefit plan, net periodic benefit costs
Amortization of net loss (gain)	$ (0.1)		$ (0.1)
Post retirement defined benefit plans and defined contribution plan
Defined benefit plan, net periodic benefit costs
Service cost	0.8	$ 0.8
Interest cost	1.3	1.2
Expected return on plan assets	(2.6)	(2.7)
Amortization of prior service cost (credit)	0.2	0.2
Amortization of net loss (gain)	0.1	0.1
Net periodic benefit cost	(0.2)	(0.4)
Post-retirement Health care plans
Defined benefit plan, net periodic benefit costs
Interest cost	0.7	0.7
Amortization of net loss (gain)	(0.2)	(0.2)
Net periodic benefit cost	0.5	0.5
Post-retirement Health care plans | Maximum
Defined benefit plan, net periodic benefit costs
Amortization of prior service cost (credit)	$ 0.1	$ 0.1

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES: - Environmental matters (Details) $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Dec. 31, 2011categoryperson
Environmental costs
Environmental capital investment	$ 68.8	$ 73.3
Peru
Environmental costs
Environmental capital investment	12.9	38
Mexico
Environmental costs
Environmental capital investment	$ 55.9	$ 35.3
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. 09, 2019m³	Sep. 30, 2019item
SUBSEQUENT EVENTS:
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	9 Months Ended	12 Months Ended
	Sep. 30, 2016lawsuit	Jun. 30, 2015itemlawsuit	Sep. 30, 2019lawsuitclaim	Dec. 31, 2015itemlawsuit	Dec. 31, 2018item	Dec. 31, 2017lawsuit	Dec. 31, 2016item
Litigation Matter
Number of collective action lawsuits		6
Number of collective action lawsuits dismissed		2
Number of lawsuits in process			3
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
Number of subsidiaries against which lawsuits were filed | item		2
Tia Maria
Litigation Matter
Number of lawsuits			4
Buenavista del Cobre, S.A. de C.V
Litigation Matter
Number of civil actions seeking damages | item				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
Norberto Bustamante et al
Litigation Matter
Number of additional constitutional lawsuits filed			2
Acciones Colectivas de Sinaloa
Litigation Matter
Number of lawsuits in process			2
Defensa Colectiva
Litigation Matter
Number of lawsuits in process			1

COMMITMENTS AND CONTINGENCIES_5

COMMITMENTS AND CONTINGENCIES: - Labor matters (Details)	1 Months Ended				3 Months Ended			9 Months Ended
	Mar. 31, 2019PEN (S/)item	Mar. 31, 2019USD ($)item	Aug. 31, 2018USD ($)item	Jun. 30, 2018	Dec. 31, 2018PEN (S/)	Sep. 30, 2018PEN (S/)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)item	Aug. 22, 2018USD ($)
Peru | Labor Matters
Labor matters
Percentage of labor unionized								64.00%
Total number of workers								4,862
Number of labor unions								6
Number of labor unions represent majority of workers								1
Number of labor unions other than majority workers unions								5
Term of agreement			3 years	3 years
Annual salary increase (as a percent)	5.00%	5.00%			5.00%	5.00%	5.00%
Labor expense	S/ 45,000	$ 13,600	$ 13,600		S/ 45,000	S/ 45,000	$ 13,600
Number of additional unions	1	1	3
Mexico | San Martin
Labor matters
Budgeted cost for rehabilitation of mine | $									$ 87,000,000
Total expense incurred on rehabilitation of mine till date | $								$ 70,200,000

COMMITMENTS AND CONTINGENCIES_6

COMMITMENTS AND CONTINGENCIES: - Others (Details) S/ in Millions	Jul. 15, 2019complaint	Jun. 30, 2018USD ($)T	May 31, 2016MW	Jul. 31, 2014MW	Jun. 30, 2014MW	Sep. 30, 2019PEN (S/)personitemkmT	Sep. 30, 2019USD ($)personitemkmT
Other commitments:
Commitment for capital projects							$ 125,900,000
Tia Maria | Peru
Other commitments:
Number of kilometer industrial railway built | km						32	32
Project budget							$ 1,400,000,000
Number Of Complaints | complaint	3
Amount spend as of the current date							$ 336,500,000
Annual production ( in tons) | T						120,000	120,000
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:
Project budget							$ 1,320,000,000
Amount spend as of the current date							1,296,800,000
Amount committed to funding for social and infrastructure improvement projects						S/ 445.0	131,700,000
Commitment liability recorded in the balance sheet							62,100,000
Development Fund Moquegua Region | Peru
Other commitments:
Amount committed to funding for social and infrastructure improvement projects						S/ 700.0	$ 207,200,000
Copper | Michiquillay | Peru
Other commitments:
Annual production ( in tons) | T		225,000
Contingent contractual obligation		$ 400,000,000
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		$ 12,500,000
Remaining amount to pay if project is developed		$ 387,500,000
Copper | Toquepala Concentrator Expansion | Peru
Other commitments:
Estimated increase in annual production (in tons) | T						257,000	257,000
Estimated increase in annual production (in percent)						51.00%	51.00%
Educational Project | Tia Maria | Peru
Other commitments:
Number of persons got benefits from the programs | person						700	700
Number of jobs expected to be generated | person						9,000	9,000
Number of Direct Jobs Expected to be Generated | person						3,600	3,600
Number of Indirect Jobs Expected to be Generated | person						5,400	5,400
Educational Project | Development Fund Moquegua Region | Peru
Other commitments:
Amount committed to funding for social and infrastructure improvement projects						S/ 108.5	$ 32,100,000
Water Treatment | Development Fund Moquegua Region | Peru
Other commitments:
Amount committed to funding for social and infrastructure improvement projects						48.4	14,300,000
Social Investment For Taxes | Development Fund Moquegua Region | Peru
Other commitments:
Amount committed to funding for social and infrastructure improvement projects						S/ 202.0	$ 59,800,000
Number of Infrastructure Projects Agreed for Construction							6
Electroperu S.A | Power purchase agreements | 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
Kallpa | Power purchase agreements | 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
Kallpa | Power purchase agreements | Peru | Maximum
Other commitments:
Purchase agreement, contracted power capacity (in megawatts) | MW			80

STOCKHOLDERS' EQUITY_ - Treasur

STOCKHOLDERS' EQUITY: - Treasury Stock (Details) - USD ($) $ in Millions	9 Months Ended		141 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Dec. 31, 2018
Activity in treasury stock
Balance at the beginning of the period	$ 3,019.6
Purchase of shares			$ 2,900
Balance at the end of the period	$ 3,039.9	$ 3,018	$ 3,039.9
Southern Copper common shares
Activity in treasury stock
Treasury stock balance at the end of the period (in shares)	111,537,217		111,537,217	111,551,617
Southern Copper common shares | Directors' Stock Award Plan
Share Based Compensation Plan, share distributions
Share Based Compensation Plan, share distributions during the period	14,400	16,000
Parent Company (Grupo Mexico) common shares | Employee Stock Purchase Plan
Share Based Compensation Plan, share distributions
Share Based Compensation Plan, share distributions during the period	400,000	1,300,000
TREASURY STOCK: | Southern Copper common shares
Activity in treasury stock
Balance at the beginning of the period	$ 2,768.3	$ 2,768.7
Used for corporate purposes	(0.4)	(0.4)
Balance at the end of the period	2,767.9	2,768.3	$ 2,767.9
TREASURY STOCK: | Parent Company (Grupo Mexico) common shares
Activity in treasury stock
Balance at the beginning of the period	251.3	232.4
Other activity, including dividend, interest and foreign currency transaction effect	20.7	17.3
Balance at the end of the period	$ 272	$ 249.7	$ 272

STOCKHOLDERS' EQUITY_ - Repurch

STOCKHOLDERS' EQUITY: - Repurchase Program (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	141 Months Ended
	Sep. 30, 2019	Dec. 31, 2008
SCC share repurchase program:
Amount authorized for share repurchase program	$ 3,000	$ 500
Number of Shares Purchased	119.5
Maximum Number of Shares that May Yet Be Purchased Under the Plan @ $39.68	2.4
Cost of purchase of shares	$ 2,900
Closing price of NYSE (in dollars per share)	$ 34.13
Percentage of ownership by parent	88.90%

STOCKHOLDERS' EQUITY_ - Directo

STOCKHOLDERS' EQUITY: - Directors' Stock Award Plan (Details) - shares	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Parent Company (Grupo Mexico) common shares
Activity in directors' stock award plan
Treasury stock balance at the end of the period (in shares)	94,147,164	100,188,809
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
Period of extension of plan	5 years
Increased share awards issued to directors	1,600

STOCKHOLDERS' EQUITY - Compensa

STOCKHOLDERS' EQUITY - Compensation Plan (Details) $ / shares in Units, $ in Millions	1 Months Ended				9 Months Ended
	Nov. 30, 2018$ / shares	Nov. 30, 2018$ / shares	Jan. 31, 2015$ / shares	Jan. 31, 2015$ / shares	Sep. 30, 2019USD ($)$ / sharesshares	Sep. 30, 2018USD ($)$ / sharesshares
Employee Stock Purchase 2015 Plan
Information related to compensation cost
Purchase price for initial subscription (in dollars per share) | (per share)			$ 2.63	$ 38.44
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 | $					$ 0.4	$ 0.4
Unrecognized compensation expense | $					$ 2.2	$ 2.8
Stock award activity, Shares
Outstanding shares at the beginning of the period | shares					1,840,336	2,293,120
Exercised (in shares) | shares					(437,386)	(306,817)
Outstanding shares at the end of the period | shares					1,402,950	1,986,303
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
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 | $					$ 0.5
Unrecognized compensation expense | $					$ 4.7
Stock award activity, Shares
Outstanding shares at the beginning of the period | shares					2,782,424
Granted (in shares) | shares					1,238,169
Outstanding shares at the end of the period | shares					4,020,593
Unit Weighted Average Grant Date Fair Value
Outstanding shares at the beginning of the period (in dollars per share) | $ / shares					$ 1.86
Granted (in dollars per share) | $ / shares					1.86
Outstanding shares at the end of the period (in dollars per share) | $ / shares					$ 1.86

STOCKHOLDERS' EQUITY_ - Non Con

STOCKHOLDERS' EQUITY: - Non Controlling Interest (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Non-controlling interest activity
Balance at the beginning of the period			$ 45.4	$ 41.7
Net earnings	$ 1.7	$ 1.3	4.7	3.9
Dividend paid			(1.1)	(1.2)
Balance at the end of the period	$ 49	$ 44.4	$ 49	$ 44.4

FAIR VALUE MEASUREMENT_ (Detail

FAIR VALUE MEASUREMENT: (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Liabilities:
Long-term debt, Carrying Value	$ 6,940.1	$ 5,960.1
Long-term debt, Fair Value	8,230.7	6,301.7
Short-term investment:
Trading securities	1	213.1
Available-for-sale debt securities:
Available-for-sale Securities, Current, Total	0.7	0.7
Quoted prices in active markets for identical assets (Level 1)
Liabilities:
Long-term debt, Carrying Value	6,190.1	5,210.7
Long-term debt, Fair Value	7,452.7	5,540
Significant other observable inputs (Level 2)
Liabilities:
Long-term debt, Carrying Value	750	749.4
Long-term debt, Fair Value	778	761.7
Fair value measurements recurring | Fair value as of the end of the period
Short-term investment:
Trading securities	1	213.1
Derivative:
Total assets, fair value	713	595.5
Fair value measurements recurring | Fair value as of the end of the period | Copper
Derivative:
Provisionally priced sales	544.7	274.3
Fair value measurements recurring | Fair value as of the end of the period | Molybdenum
Derivative:
Provisionally priced sales	166.6	107.4
Fair value measurements recurring | Asset backed securities | Fair value as of the end of the period
Available-for-sale debt securities:
Available-for-sale debt securities	0.4	0.4
Fair value measurements recurring | Mortgage backed securities | Fair value as of the end of the period
Available-for-sale debt securities:
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	1	213.1
Derivative:
Total assets, fair value	712.3	594.8
Fair value measurements recurring | Quoted prices in active markets for identical assets (Level 1) | Copper
Derivative:
Provisionally priced sales	544.7	274.3
Fair value measurements recurring | Quoted prices in active markets for identical assets (Level 1) | Molybdenum
Derivative:
Provisionally priced sales	166.6	107.4
Fair value measurements recurring | Significant other observable inputs (Level 2)
Available-for-sale debt securities:
Available-for-sale Securities, Current, Total	0.7	0.7
Fair value measurements recurring | Significant other observable inputs (Level 2) | Asset backed securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.4	0.4
Fair value measurements recurring | Significant other observable inputs (Level 2) | Mortgage backed securities
Available-for-sale debt securities:
Available-for-sale debt securities	$ 0.3	$ 0.3

REVENUE_ - Revenue by Geographi

REVENUE: - Revenue by Geographical Areas (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue Recognition
Net sales	$ 1,859.5	$ 1,723.7	$ 5,431	$ 5,402.1
Corporate, other and eliminations
Revenue Recognition
Net sales	(18.6)	(17.2)	(63.9)	(55.6)
Mexican Open-pit | Operating segment
Revenue Recognition
Net sales	982.4	995.1	3,009.1	3,124.9
Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	106.7	107.3	350.1	409.6
Peruvian Operations | Operating segment
Revenue Recognition
Net sales	789	638.5	2,135.7	1,923.2
Mexico
Revenue Recognition
Net sales	401.5	398.5	1,199.9	1,277.6
Mexico | Corporate, other and eliminations
Revenue Recognition
Net sales	(18.6)	(17.2)	(63.9)	(55.6)
Mexico | Mexican Open-pit | Operating segment
Revenue Recognition
Net sales	338.3	329.3	1,002.5	1,026.2
Mexico | Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	81.8	86.4	261.3	307
United States
Revenue Recognition
Net sales	342.2	304.4	910.5	927.6
United States | Mexican Open-pit | Operating segment
Revenue Recognition
Net sales	280.4	263.1	817.3	782.4
United States | Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	3.1	0.5	6.2	6.1
United States | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	58.7	40.8	87	139.1
Peru
Revenue Recognition
Net sales	75.2	92.6	255.6	292.7
Peru | Mexican Open-pit | Operating segment
Revenue Recognition
Net sales			1.6
Peru | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	75.2	92.6	254	292.7
Brazil
Revenue Recognition
Net sales	49.7	62.5	154.9	212
Brazil | Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	1	6.6	13.3	28.8
Brazil | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	48.7	55.9	141.6	183.2
Chile
Revenue Recognition
Net sales	64.5	42.4	144.9	102.1
Chile | Mexican Open-pit | Operating segment
Revenue Recognition
Net sales	0.1		1.3
Chile | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	64.4	42.4	143.6	102.1
Other American countries
Revenue Recognition
Net sales	11.2	15.7	39.2	45.7
Other American countries | Mexican Open-pit | Operating segment
Revenue Recognition
Net sales	10.1	15.2	34.1	41.6
Other American countries | Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	0.7	0.5	2	2.9
Other American countries | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	0.4		3.1	1.2
Switzerland
Revenue Recognition
Net sales	263.9	179.6	872.7	480.1
Switzerland | Mexican Open-pit | Operating segment
Revenue Recognition
Net sales	171.1	141.4	579.4	340.4
Switzerland | Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	11.3	6.8	28.4	33.9
Switzerland | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	81.5	31.4	264.9	105.8
Italy
Revenue Recognition
Net sales	62.3	72.8	218.6	259.6
Italy | Mexican Open-pit | Operating segment
Revenue Recognition
Net sales	5.7	5.1	42.7	18.2
Italy | Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	2	3.4	10.3	16.8
Italy | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	54.6	64.3	165.6	224.6
Spain
Revenue Recognition
Net sales	46.7	42	139	130.7
Spain | Mexican Open-pit | Operating segment
Revenue Recognition
Net sales	46.7	42	139	130.7
Other European Countries
Revenue Recognition
Net sales	67.2	101.2	248.5	281.5
Other European Countries | Mexican Open-pit | Operating segment
Revenue Recognition
Net sales	24.8	74	70.3	195.7
Other European Countries | Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	4.4	2.9	19.2	13.4
Other European Countries | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	38	24.3	159	72.4
Singapore
Revenue Recognition
Net sales	283.1	269	667.8	832.1
Singapore | Mexican Open-pit | Operating segment
Revenue Recognition
Net sales	68	104.9	198.5	389
Singapore | Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	2.3		8.7
Singapore | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	212.8	164.1	460.6	443.1
Japan
Revenue Recognition
Net sales	127.9	109.3	387.9	401.9
Japan | Mexican Open-pit | Operating segment
Revenue Recognition
Net sales	21.3	(4.7)	37.3	68.7
Japan | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	106.6	114	350.6	333.2
Other Asian countries
Revenue Recognition
Net sales	64.1	33.7	191.5	158.5
Other Asian countries | Mexican Open-pit | Operating segment
Revenue Recognition
Net sales	15.9	24.8	85.1	132
Other Asian countries | Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	0.1	0.2	0.7	0.7
Other Asian countries | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	$ 48.1	$ 8.7	$ 105.7	$ 25.8

REVENUE_ - Revenue by Segment (

REVENUE: - Revenue by Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue Recognition
Net sales	$ 1,859.5	$ 1,723.7	$ 5,431	$ 5,402.1
Corporate, other and eliminations
Revenue Recognition
Net sales	(18.6)	(17.2)	(63.9)	(55.6)
Mexican Open-pit | Operating segment
Revenue Recognition
Net sales	982.4	995.1	3,009.1	3,124.9
Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	106.7	107.3	350.1	409.6
Peruvian Operations | Operating segment
Revenue Recognition
Net sales	789	638.5	2,135.7	1,923.2
Copper
Revenue Recognition
Net sales	1,477.4	1,391.5	4,341.9	4,353.4
Copper | Corporate, other and eliminations
Revenue Recognition
Net sales	(11)	(10)	(38.2)	(32.2)
Copper | Mexican Open-pit | Operating segment
Revenue Recognition
Net sales	809.6	840.8	2,504.9	2,661.9
Copper | Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	11.5	9.9	34.5	37
Copper | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	667.3	550.8	1,840.7	1,686.7
Molybdenum
Revenue Recognition
Net sales	156.5	137.6	429.4	378.5
Molybdenum | Mexican Open-pit | Operating segment
Revenue Recognition
Net sales	91.2	89.2	274.8	254.2
Molybdenum | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	65.3	48.4	154.6	124.3
Silver
Revenue Recognition
Net sales	88.6	71.7	234.1	226
Silver | Corporate, other and eliminations
Revenue Recognition
Net sales	(9)	(6.6)	(21.3)	(21.2)
Silver | Mexican Open-pit | Operating segment
Revenue Recognition
Net sales	49.8	42.5	137.6	133.2
Silver | Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	24.7	19	59.1	63.4
Silver | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	23.1	16.8	58.7	50.6
Zinc
Revenue Recognition
Net sales	57.2	63.2	209.7	252.9
Zinc | Corporate, other and eliminations
Revenue Recognition
Net sales	2.6		(1.6)	(0.1)
Zinc | Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	54.6	63.2	211.3	253
Other
Revenue Recognition
Net sales	79.8	59.7	215.9	191.3
Other | Corporate, other and eliminations
Revenue Recognition
Net sales	(1.2)	(0.6)	(2.8)	(2.1)
Other | Mexican Open-pit | Operating segment
Revenue Recognition
Net sales	31.8	22.6	91.8	75.6
Other | Mexican IMMSA Unit | Operating segment
Revenue Recognition
Net sales	15.9	15.2	45.2	56.2
Other | Peruvian Operations | Operating segment
Revenue Recognition
Net sales	$ 33.3	$ 22.5	$ 81.7	$ 61.6

REVENUE_ - Receivables by repor

REVENUE: - Receivables by reporting segment (Details) $ in Millions	9 Months Ended
	Sep. 30, 2019USD ($)T	Dec. 31, 2018USD ($)
Opening and closing balances of receivables
Trade receivables	$ 842	$ 822.4
Related parties, current	22.3	101.5
Related parties, non-current	60
Corporate, other and eliminations
Opening and closing balances of receivables
Related parties, current	$ 8.2	19.9
Copper concentrates
Long Term Contracts
Long term contracts | T	1,090,000
Copper cathodes
Long Term Contracts
Long term contracts | T	48,000
Molybdenum concentrates
Long Term Contracts
Long term contracts | T	24,446
Sulfuric acid
Long Term Contracts
Long term contracts | T	331,620
Mexican Open-pit | Operating segment
Opening and closing balances of receivables
Trade receivables	$ 430.1	505.9
Related parties, current	14.1	81.6
Related parties, non-current	60
Mexican IMMSA Unit | Operating segment
Opening and closing balances of receivables
Trade receivables	41.8	50.5
Peruvian Operations | Operating segment
Opening and closing balances of receivables
Trade receivables	$ 370.1	$ 266

REVENUE_ - Provisionally prices

REVENUE: - Provisionally prices sales (Details) lb in Millions, $ in Millions	Sep. 30, 2019USD ($)lb$ / item
Copper
Provisionally priced sales:
Provisional price sales adjustment amounts included in accounts receivable and net sales | $	$ 19.9
Copper | July 2019 to November 2019
Provisionally priced sales:
Sales volume (in million lbs.) | lb	210.4
Provisional price | $ / item	2.59
Molybdenum
Provisionally priced sales:
Provisional price sales adjustment amounts included in accounts receivable and net sales | $	$ 6
Molybdenum | July 2019 to September 2019
Provisionally priced sales:
Sales volume (in million lbs.) | lb	14.1
Provisional price | $ / item	11.78

SEGMENT AND RELATED INFORMATI_3

SEGMENT AND RELATED INFORMATION: (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)segment	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Financial information related to segments
Number of reportable segments | segment			3
Financial information relating to segments
Net sales	$ 1,859.5	$ 1,723.7	$ 5,431	$ 5,402.1
Cost of sales (exclusive of depreciation, amortization and depletion)	906.5	824	2,617.9	2,552.2
Selling, general and administrative	32	26.4	91.4	76.7
Depreciation, amortization and depletion	200.3	170.6	580.6	495.2
Exploration	6.9	6	19.9	20.3
Operating income	713.8	696.7	2,121.2	2,257.7
Interest, net	(78.7)	(64.8)	(232.5)	(197.2)
Other income (expense)	(6.3)	(7.6)	22	(13.1)
Income taxes	(241)	(257.9)	(730)	(803.6)
Equity earnings of affiliate	3.5	4.3	4.2	9.9
Non-controlling interest	(1.7)	(1.3)	(4.7)	(3.9)
Net income attributable to SCC	389.6	369.4	1,180.2	1,249.8
Capital investment	182.7	282.3	536.1	831.8
Property and mine development, net	9,395.3	9,311.8	9,395.3	9,311.8	$ 9,403.8
Total assets	16,494.4	14,316.7	16,494.4	14,316.7	$ 14,484.8
Intersegment sales
Financial information relating to segments
Net sales	(18.6)	(17.2)	(63.9)	(55.6)
Corporate, other and eliminations
Financial information relating to segments
Net sales	(18.6)	(17.2)	(63.9)	(55.6)
Cost of sales (exclusive of depreciation, amortization and depletion)	(16.9)	(18.8)	(70.3)	(60.5)
Selling, general and administrative	1.2	0.2	5.8	1.6
Depreciation, amortization and depletion	7.1	2.4	29	20.8
Exploration	2.2	2.3	2.5	3.5
Operating income	(12.2)	(3.3)	(30.9)	(21)
Capital investment	2.4	0.7	4.5	19.4
Property and mine development, net	337.8	553.3	337.8	553.3
Total assets	2,447.2	465	2,447.2	465
Reportable subsegments
Financial information relating to segments
Net sales	1,859.5	1,723.7	5,431	5,402.1
Mexican Open-pit | Operating segment
Financial information relating to segments
Net sales	982.4	995.1	3,009.1	3,124.9
Cost of sales (exclusive of depreciation, amortization and depletion)	390.2	398.8	1,194.9	1,214.8
Selling, general and administrative	19.4	15.8	51.4	41.4
Depreciation, amortization and depletion	91.1	95.1	263.9	269.5
Exploration	0.5	0.4	1.4	1.5
Operating income	481.2	485	1,497.5	1,597.7
Capital investment	59.4	53.7	180.5	197.9
Property and mine development, net	4,691.2	4,579.5	4,691.2	4,579.5
Total assets	8,093.3	8,122.7	8,093.3	8,122.7
Mexican Open-pit | Reportable subsegments | Operating segment
Financial information relating to segments
Net sales	982.4	995.1	3,009.1	3,124.9
Mexican IMMSA Unit | Operating segment
Financial information relating to segments
Net sales	106.7	107.3	350.1	409.6
Cost of sales (exclusive of depreciation, amortization and depletion)	80.7	74.7	285.3	271.2
Selling, general and administrative	2	1.9	6	6.8
Depreciation, amortization and depletion	13.7	11.5	39.9	33.6
Exploration	2.3	1.1	7	3.6
Operating income	8	18.1	11.9	94.4
Capital investment	32.1	10.2	79.6	32.6
Property and mine development, net	487.6	433.4	487.6	433.4
Total assets	839.3	974.1	839.3	974.1
Mexican IMMSA Unit | Intersegment sales
Financial information relating to segments
Net sales	18.6	17.2	63.9	55.6
Mexican IMMSA Unit | Reportable subsegments | Operating segment
Financial information relating to segments
Net sales	88.1	90.1	286.2	354
Peruvian Operations | Operating segment
Financial information relating to segments
Net sales	789	638.5	2,135.7	1,923.2
Cost of sales (exclusive of depreciation, amortization and depletion)	452.5	369.3	1,208	1,126.7
Selling, general and administrative	9.4	8.5	28.2	26.9
Depreciation, amortization and depletion	88.4	61.6	247.8	171.3
Exploration	1.9	2.2	9	11.7
Operating income	236.8	196.9	642.7	586.6
Capital investment	88.8	217.7	271.5	581.9
Property and mine development, net	3,878.7	3,745.6	3,878.7	3,745.6
Total assets	5,114.6	4,754.9	5,114.6	4,754.9
Peruvian Operations | Reportable subsegments | Operating segment
Financial information relating to segments
Net sales	$ 789	$ 638.5	$ 2,135.7	$ 1,923.2

SUBSEQUENT EVENTS_ (Details)

SUBSEQUENT EVENTS: (Details)	Oct. 17, 2019$ / shares	Jul. 15, 2019complaint
Tia Maria | Peru
SUBSEQUENT EVENTS:
Number of complaints | complaint		3
Subsequent Events
SUBSEQUENT EVENTS:
Quarterly dividend authorized (in dollars per share) | $ / shares	$ 0.40