Quarterly report pursuant to Section 13 or 15(d)

Mineral Properties - rollforward (Details)

v3.4.0.3
Mineral Properties - rollforward (Details)
$ in Thousands
 3 Months Ended
Mar. 31, 2016
USD ($)
Balance at beginning of period $ 50,610
Increase in reclamation costs 150
Property write-offs (189)
Amortization (710)
Balance at end of period 50,050
Lost Creek Property  
Balance at beginning of period 16,662
Increase in reclamation costs 338
Amortization (710)
Balance at end of period 16,290
Other Us Properties [Member]  
Balance at beginning of period 13,210
Balance at end of period 13,210
Path Finder Mines [Member]  
Balance at beginning of period 20,738
Increase in reclamation costs (188)
Balance at end of period $ 20,550