Inventory (Details) (USD $)	3 Months Ended		46 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Dec. 31, 2011
Current:
Concentrate stockpiles	$ 1,832,000		$ 1,832,000	$ 3,704,000
Raw materials	33,540,000		33,540,000	44,770,000
Work in process	14,099,000		14,099,000	16,602,000
Finished goods	58,991,000		58,991,000	45,045,000
Materials and supplies	2,025,000		2,025,000	1,822,000
Total current	110,487,000		110,487,000	111,943,000
Long-term:
Concentrate stockpiles	1,867,000		1,867,000	1,144,000
Raw materials	8,328,000		8,328,000	3,186,000
Finished goods	5,000		5,000	32,000
Total long-term	10,200,000		10,200,000	4,362,000
Production costs that would have been allocated to additional tons produced, assuming operations at normal production rates	3,000,000	2,600,000	20,800,000
Write-down of inventory as a result of production or purchase costs in excess of net realizable value	6,600,000	600,000	30,400,000
Write-down of work-in-process inventory and stockpile based on estimated REO quantities		$ 1,300,000	$ 5,000,000