Note 11. Derivative Instruments (Tables)

3 Months Ended

Mar. 31, 2012

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

March 31, 2012	Metric tonnes under contract				Average price per pound
	Zinc		Lead		Zinc		Lead
Contracts on provisional sales
2012 settlements		6,250		1,300	$	0.94	$	0.96
Contracts on forecasted sales
2012 settlements		11,850		5,100	$	1.12	$	1.13
2013 settlements		8,675		13,250	$	1.13	$	1.15

December 31, 2011	Metric tonnes under contract				Average price per pound
	Zinc		Lead		Zinc		Lead
Contracts on provisional sales
2012 settlements		9,600		2,600	$	0.86	$	0.89
Contracts on forecasted sales
2012 settlements		20,500		15,900	$	1.12	$	1.12
2013 settlements		8,275		11,150	$	1.14	$	1.17