ASSET RETIREMENT OBLIGATIONS - Retirement obligation rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reclamation obligations
Reclamation Adjustment	$ 1,851	$ 2,259	$ 1,426
Remediation Accretion	1,680	1,205	635
Reclamation and remediation expense	3,531	3,464	2,061
Changes in the asset retirement obligations
Asset retirement obligation, beginning of the period	29,402	24,722
Settlements	(513)	(392)
Accretion of liability	1,680	1,205
Adjustment reflecting updated estimates	1,012	5,024
Foreign exchange revaluation	620	(1,157)
Asset retirement obligation, ending balance	32,201	29,402	$ 24,722
Current portion	(2,610)	(734)
Long-term portion	29,591	28,668
Black Fox
Reclamation obligations
Reclamation Adjustment	5,300
Gold Bar mine
Reclamation obligations
Reclamation Adjustment	$ 4,200	$ 3,700

Amount of reclamation adjustments during the period.

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Amount of reclamation and remediation expenses.

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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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 45
-Paragraph 1
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-Publisher FASB
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-Topic 420
-SubTopic 10
-Section 35
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6394232&loc=d3e17558-110866

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The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability.

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Current portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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Amount of foreign currency translation gain (loss) which decreases (increases) asset retirement obligations.

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Amount of asset retirement obligations settled, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset.

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Amount of increase (decrease) in the asset retirement obligation from changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Noncurrent portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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