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PLANT AND EQUIPMENT AND MINERAL PROPERTIES (Narrative) (Details) - USD ($)		3 Months Ended	12 Months Ended
	May 27, 2016	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Abandonment of mineral properties		$ 1,036,000	$ 1,036,000	$ 2,770,000	$ 0
Nichols Ranch
Property, Plant and Equipment [Line Items]
Depreciation			$ 4,430,000	$ 2,370,000	$ 0
Roca Honda
Property, Plant and Equipment [Line Items]
Number of shares issued (in shares)	1,212,173
Percentage of voting interests acquired	40.00%
Value assigned of equity interest issued	$ 2,630,000
Cash payable	$ 4,500,000