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LONG-TERM DEBT (Details) - USD ($) $ in Millions		3 Months Ended	6 Months Ended
LONG-TERM DEBT (Details) - USD ($) $ in Millions	Aug. 10, 2018	Jun. 30, 2019	Jun. 30, 2019	Jun. 30, 2018
Scheduled minimum interest payments
2019		$ 2.5	$ 2.5
2020		4.7	4.7
2021		2.0	2.0
Affiliate of Robert McEwen
LONG-TERM DEBT
Debt interest expense		0.6	1.2
Term Loan
LONG-TERM DEBT
Face amount	$ 50.0
Term of debt instrument	3 years
Interest Expense		1.2	2.4
Interest costs capitalized			0.6
Term Loan \| Gold Bar Complex
LONG-TERM DEBT
Stated interest rate (as a percent)	9.75%
Scheduled minimum debt repayments
2020		10.0	10.0
2021		$ 40.0	$ 40.0