STOCKHOLDERS' EQUITY: (Tables)

12 Months Ended

Dec. 31, 2011

STOCKHOLDERS' EQUITY.

Schedule of activity in treasury stock

	2011			2010
Southern Copper common shares
Balance as of January 1,	$	461.0		$	460.7
Purchase of shares	273.6			0.5
Used for corporate purposes	(0.5		)	(0.2		)
Balance as of December 31,	734.1			461.0
Parent Company (Grupo Mexico) common shares
Balance as of January 1,	161.7			142.7
Other activity, including dividend, interest and currency translation effect	2.0			19.0
Balance as of December 31,	163.7			161.7
Treasury stock balance as of December 31,	$	897.8		$	622.7

Schedule of share repurchase program activity

Period		Total Number of Shares	Average Price Paid per	Total Number of Shares Purchased as Part of Publicly	Maximum Number of Shares that May Yet Be Purchased Under the Plan	Total Cost($ in
From	To	Purchased	Share	Announced Plan	@ $30.18(1)	millions)
2008:
08/11/08	12/31/08	28,510,150	13.49	28,510,150		$	384.7
2009:
01/12/09	09/30/09	4,912,000	14.64	33,422,150		71.9
2010:
05/05/10	10/14/10	15,600	29.69	33,437,750		0.5
2011:
05/01/11	05/31/11	14,400	37.06	33,452,150		0.5
06/01/11	06/30/11	4,567,520	32.30	38,019,670		147.5
08/03/11	08/22/11	2,762,811	29.63	40,782,481		81.9
09/22/11	09/30/11	1,069,669	26.59	41,852,150		28.4
10/03/11	10/21/11	620,000	24.73	42,472,150		15.3
		9,034,400	30.29			273.7
Total purchased		42,472,150	17.20		8,922,746	$	730.7

(2)NYSE price at December 31, 2011

Schedule of activity in Directors' Stock Award Plan

	2011		2010
Total SCC shares reserved for the plan	600,000		600,000
Total shares granted at January 1,	(256,800	)	(241,200	)
Granted in the period	(14,400	)	(15,600	)
Total shares granted at December 31,	(271,200	)	(256,800	)
Remaining shares reserved	328,800		343,200

Deduction from the amount to be paid to the employee in case of voluntary resignation

If the resignation occurs during:	% Deducted
1st year after the grant date	90	%
2nd year after the grant date	80	%
3rd year after the grant date	70	%
4th year after the grant date	60	%
5th year after the grant date	50	%
6th year after the grant date	40	%
7th year after the grant date	20	%

Deduction from the amount to be paid to the employee in case of involuntary termination

If the termination occurs during:	% Deducted
1st year after the grant date	100	%
2nd year after the grant date	95	%
3rd year after the grant date	90	%
4th year after the grant date	80	%
5th year after the grant date	70	%
6th year after the grant date	60	%
7th year after the grant date	50	%

Employee stock purchase plan

Share based compensation plan

Schedule of stock award activity of the Employee Stock Purchase Plan

	Shares		Unit Weighted Average Grant Date Fair Value
Outstanding shares at January 1, 2010	11,556,625		$	1.16
Granted	—		—
Exercised	—		—
Forfeited	(635,932	)	1.16
Outstanding shares at December 31, 2010	10,920,693		$	1.16
Outstanding shares at January 1, 2011	10,920,693		$	1.16
Granted	—		—
Exercised	(3,402,855	)	1.16
Forfeited	(247,497	)	1.16
Outstanding shares at December 31, 2011	7,270,341		$	1.16

New Employee Stock Purchase Plan

Share based compensation plan

Schedule of stock-based compensation expense and unrecognized compensation expense

	Shares		Unit Weighted AverageGrant Date Fair Value
Outstanding shares at January 1, 2011	3,901,901		$	2.05
Granted	51,923		2.05
Exercised	—		—
Forfeited	(146,678	)	2.05
Outstanding shares at December 31, 2011	3,807,146		$	2.05