Note 10 - Derivative Instruments (Tables)

12 Months Ended

Dec. 31, 2013

Derivative Instruments and Hedging Activities Disclosure [Abstract]

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

December 31, 2013	Ounces/pounds under contract (in 000's)								Average price per ounce/pound
	Silver (ounces)		Gold (ounces)		Zinc (pounds)		Lead (pounds)		Silver (ounces)		Gold (ounces)		Zinc (pounds)		Lead (pounds)
Contracts on provisional sales
2014 settlements		673		3		11,188		3,472	$	19.50	$	1,205	$	0.89	$	1.00
Contracts on forecasted sales
2014 settlements		—		—		31,967		34,282	N/A		N/A		$	1.00	$	1.04
2015 settlements		—		—		39,683		36,982	N/A		N/A		$	0.96	$	1.07
2016 settlements		—		—		3,803		30,589	N/A		N/A		$	0.93	$	1.03

December 31, 2012	Ounces/pounds under contract (in 000's)								Average price per ounce/pound
	Silver (ounces)		Gold (ounces)		Zinc (pounds)		Lead (pounds)		Silver (ounces)	Gold (ounces)	Zinc (pounds)		Lead (pounds)
Contracts on provisional sales
2013 settlements		—		—		14,991		6,945	N/A	N/A	$	0.95	$	1.00
Contracts on forecasted sales
2013 settlements		—		—		35,935		32,794	N/A	N/A	$	0.96	$	1.11
2014 settlements		—		—		30,203		33,069	N/A	N/A	$	0.98	$	1.03
2015 settlements		—		—		3,307		23,534	N/A	N/A	$	1.01	$	1.06