Note 11 - Derivative Instruments (Tables)

9 Months Ended

Sep. 30, 2017

Notes Tables

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

September 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		1,399		5		19,070		2,535	$	17.18	$	1,298	$	1.33	$	1.07
2018 settlements		—		—		2,370		—		N/A		N/A	$	1.38		N/A
Contracts on forecasted sales
2017 settlements		—		—		441		2,866		N/A		N/A	$	1.23	$	1.05
2018 settlements		—		—		39,463		17,968		N/A		N/A	$	1.27	$	1.05
2019 settlements		—		—		14,330		8,267		N/A		N/A	$	1.30	$	1.07
2020 settlements		—		—		3,307		2,205		N/A		N/A	$	1.27	$	1.07

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