Note 11 - Derivative Instruments (Tables)

6 Months Ended

Jun. 30, 2017

Notes Tables

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

June 30, 2017	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
2017 settlements		1,379		7		15,873		6,724	$	17.14	$	1,259	$	1.21	$	0.97
Contracts on forecasted sales
2017 settlements		—		—		6,834		6,504		N/A		N/A	$	1.26	$	1.05
2018 settlements		—		—		28,329		16,314		N/A		N/A	$	1.23	$	1.05
2019 settlements		—		—		1,102		1,102		N/A		N/A	$	1.21	$	1.06

December 31, 2016	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
2017 settlements		1,295		4		19,070		7,441	$	16.29	$	1,172	$	1.18	$	0.97
Contracts on forecasted sales
2017 settlements		—		—		35,384		17,637		N/A		N/A	$	1.19	$	1.03
2018 settlements		—		—		13,779		5,732		N/A		N/A	$	1.21	$	1.05