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PLANT AND EQUIPMENT AND MINERAL PROPERTIES - Schedule of Summary of Mineral Properties (Details) - USD ($) $ in Thousands | Mar. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Property, Plant and Equipment [Line Items] |  |
Mineral properties | $ 92,380 | $ 92,625
Uranerz ISR properties |  |
Property, Plant and Equipment [Line Items] |  |
Mineral properties | 34,815 | 35,060
In-situ recovery total |  |
Property, Plant and Equipment [Line Items] |  |
Mineral properties | 34,815 | 35,060
Sheep Mountain |  |
Property, Plant and Equipment [Line Items] |  |
Mineral properties | 34,183 | 34,183
Roca Honda |  |
Property, Plant and Equipment [Line Items] |  |
Mineral properties | 22,095 | 22,095
Other |  |
Property, Plant and Equipment [Line Items] |  |
Mineral properties | 1,287 | 1,287
Conventional total |  |
Property, Plant and Equipment [Line Items] |  |
Mineral properties | $ 57,565 | $ 57,565

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- Definition Mineral properties, net of adjustments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section 25 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=56951519&loc=d3e64895-109465 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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