CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
OPERATING EXPENSES:
Exploration and evaluation	$ 756	$ 1,077	$ 1,032
General and administrative expense	6,373	6,050	8,703
TOTAL OPERATING EXPENSES	7,129	7,127	9,735
(LOSS) FROM OPERATIONS	(7,129)	(7,127)	(9,735)
OTHER INCOME/(EXPENSE):
Loss on Termination of Power Transmission Contract			(4,317)
Loss on Extinguishment of Senior Convertible Promissory Notes			(971)
Interest expense	(942)	(961)	(1,100)
TOTAL OTHER (EXPENSE)/INCOME, NET	(942)	(961)	(6,388)
(LOSS) BEFORE INCOME TAXES	(8,071)	(8,088)	(16,123)
CONSOLIDATED NET (LOSS)	(8,071)	(8,088)	(16,123)
Less: Net loss attributable to CRNCI	26	21	900
NET LOSS ATTRIBUTABLE TO GMI	$ (8,045)	$ (8,067)	$ (15,223)
Basic and diluted net loss attributable to GMI per share of common stock (in dollars per share)	$ (0.07)	$ (0.07)	$ (0.16)
Weighted average number of shares outstanding - basic and diluted (in shares)	114,315	110,521	97,056
COMPREHENSIVE (LOSS)	$ (8,045)	$ (8,067)	$ (15,223)