XML 67 R52.htm IDEA: XBRL DOCUMENT v3.21.2
Property, Plant and Mine Development, net - Summary of Property, Equipment and Mine Development (Details) - USD ($)
$ in Thousands
Sep. 30, 2021
Dec. 31, 2020
Property, equipment and mine development - net    
Property and equipment, gross [1] $ 167,632 $ 153,595
Accumulated depreciation and amortization (101,315) (91,084)
Total property, equipment and mine development - net 66,317 62,511
Accrued capital expenditures 1,000 1,000
Asset retirement costs    
Property, equipment and mine development - net    
Property and equipment, gross 1,071 1,064
Construction-in-progress    
Property, equipment and mine development - net    
Property and equipment, gross 13,265 7,158
Furniture and office equipment    
Property, equipment and mine development - net    
Property and equipment, gross 1,896 1,839
Land    
Property, equipment and mine development - net    
Property and equipment, gross 230 230
Light vehicles and other mobile equipment    
Property, equipment and mine development - net    
Property and equipment, gross 2,236 2,192
Machinery and equipment    
Property, equipment and mine development - net    
Property and equipment, gross 33,083 31,227
Mill facilities and infrastructure    
Property, equipment and mine development - net    
Property and equipment, gross 24,455 24,407
Mine Development    
Property, equipment and mine development - net    
Property and equipment, gross 89,760 83,859
Software and licenses    
Property, equipment and mine development - net    
Property and equipment, gross $ 1,636 $ 1,619
[1] Includes accrued capital expenditures of $1.0 million both at September 30, 2021 and December 31, 2020.