SUBSEQUENT EVENT (Details) - Subsequent Event - Royalty - USD ($) $ in Thousands	Jun. 30, 2018	Apr. 19, 2016
Subsequent Event
Required payment of gross revenue less allowable deductions to the tiered net smelter return royalty on the El Gallo 1 Mine (as a percent)		3.50%
Purchase price		$ 5,250
Conditional deferred payment to be made provided the El Gallo 1 Mine is in operation at the time of the payment	$ 1,000

The conditional deferred payment to be made provided the El Gallo 1 Mine is in operation at the time of the payment.

No definition available.

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- Definition

The required payment of gross revenue less allowable deductions to the tiered net smelter return royalty (the “Royalty”) on the El Gallo 1 Mine.

+ References

No definition available.

+ Details

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- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3213-108585

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- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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- Details

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