Note 11. Derivative Instruments (Tables)

6 Months Ended

Jun. 30, 2011

Schedule of Derivative Liabilities at Fair Value [Table Text Block]

	June 30,		December 31,
	2011		2010
Current derivative contract liabilities	$	10,510	$	20,016
Other non-current liabilities		1,087		779

Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance [Table Text Block]

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2011		2010		2011			2010
Sales of products	$	49	$	6,351	$	703		$	6,351
Gain (loss) on derivatives contracts		558		1,999		(1,475	)		1,999

Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]

	Metric tonnes under contract				Average price per pound
	Zinc		Lead		Zinc		Lead
Contracts on provisional sales
2011 settlements		8,100		4,500	$	1.02	$	1.17
Contracts on forecasted sales
2011 settlements		7,350		6,175	$	0.96	$	1.01
2012 settlements		26,650		18,000	$	1.11	$	1.11
2013 settlements		4,700		8,300	$	1.16	$	1.16