Note 11 - Derivative Instruments (Tables)

6 Months Ended

Jun. 30, 2014

Derivative Instruments and Hedging Activities Disclosure [Abstract]

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

June 30, 2014	Ounces/pounds under contract (in 000's)								Average price per ounce/pound
	Silver		Gold		Zinc		Lead		Silver		Gold		Zinc		Lead
	(ounces)		(ounces)		(pounds)		(pounds)		(ounces)		(ounces)		(pounds)		(pounds)
Contracts on provisional sales
2014 settlements		786		4		12,236		6,449	$	18.90	$	1,263	$	0.95	$	0.95
Contracts on forecasted sales
2014 settlements		—		—		19,566		14,330	N/A		N/A		$	1.01	$	1.09
2015 settlements		—		—		49,604		40,179	N/A		N/A		$	0.96	$	1.07
2016 settlements		—		—		32,022		32,132	N/A		N/A		$	0.97	$	1.03
2017 settlements		—		—		661		—	N/A		N/A		$	0.99	N/A

December 31, 2013	Ounces/pounds under contract (in 000's)								Average price per ounce/pound
	Silver		Gold		Zinc		Lead		Silver		Gold		Zinc		Lead
	(ounces)		(ounces)		(pounds)		(pounds)		(ounces)		(ounces)		(pounds)		(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