RECLAMATION AND REMEDIATION LIABILITIES - Reclamation and Accretion (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reclamation obligations
Reclamation adjustment reflecting updated estimates	$ 1,045	$ (113)	$ 1,851
Reclamation accretion	2,405	1,901	1,680
Total	3,450	1,788	$ 3,531
Projects in Nevada
Reclamation obligations
Reclamation adjustment reflecting updated estimates	500	$ 100
Black Fox Complex
Reclamation obligations
Reclamation adjustment reflecting updated estimates	600
Tonkin Properties
Reclamation obligations
Reclamation adjustment reflecting updated estimates	$ 100

Amount recognized for the passage of time, typically for liabilities, that have been discounted to their net present values. Excludes accretion associated with asset retirement obligations.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-Name Accounting Standards Codification
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6394232&loc=d3e17558-110866

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