Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 278,504	$ 266,463
Accounts receivable:
Trade	5,849	10,996
Other, net	6,445	9,313
Inventories:
Concentrates, doré, and stockpiled ore	11,885	13,692
Materials and supplies	12,362	12,503
Current deferred income taxes	23,534	27,810
Other current assets	14,851	21,967
Total current assets	353,430	362,744
Non-current investments	3,584	3,923
Non-current restricted cash and investments	866	866
Properties, plants, equipment and mineral interests, net	938,879	923,212
Non-current deferred income taxes	89,478	88,028
Other non-current assets and deferred charges	11,496	17,317
Total assets	1,397,733	1,396,090
Current liabilities:
Accounts payable and accrued liabilities	30,125	37,831
Accrued payroll and related benefits	9,008	12,878
Accrued taxes	13,244	10,354
Current portion of capital leases	4,797	4,005
Current portion of accrued reclamation and closure costs	40,230	42,248
Total current liabilities	97,404	107,316
Capital leases	8,826	6,265
Accrued reclamation and closure costs	111,706	111,563
Other noncurrent liabilities	30,476	30,833
Total liabilities	248,412	255,977
Commitments and contingencies
Preferred stock, 5,000,000 shares authorized:
Series B preferred stock, $0.25 par value, 157,816 shares issued and outstanding, liquidation preference — $7,891	39	39
Common stock, $0.25 par value, authorized 500,000,000 shares; issued and outstanding 2012 — 285,298,389 shares and 2011 — 285,289,924 shares	71,422	71,420
Capital surplus	1,215,785	1,215,229
Accumulated deficit	(111,688)	(120,557)
Accumulated other comprehensive loss	(23,717)	(23,498)
Less treasury stock, at cost; 392,645 shares	(2,520)	(2,520)
Total shareholders’ equity	1,149,321	1,140,113
Total liabilities and shareholders’ equity	$ 1,397,733	$ 1,396,090