CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
OPERATING EXPENSES:
Exploration and evaluation	$ 1,077	$ 1,032	$ 2,097
General and administrative expense	6,050	8,703	8,872
TOTAL OPERATING EXPENSES	7,127	9,735	10,969
LOSS FROM OPERATIONS	(7,127)	(9,735)	(10,969)
OTHER INCOME/(EXPENSE):
Loss on Termination of Power Transmission Contract		(4,317)
Loss on Extinguishment of Senior Convertible Promissory Notes		(971)
Interest expense	(961)	(1,100)	(29)
TOTAL OTHER (EXPENSE)/INCOME, NET	(961)	(6,388)	(29)
LOSS BEFORE INCOME TAXES	(8,088)	(16,123)	(10,998)
CONSOLIDATED NET LOSS	(8,088)	(16,123)	(10,998)
Less: Net loss attributable to CRNCI	21	900	38
NET LOSS ATTRIBUTABLE TO GMI	$ (8,067)	$ (15,223)	$ (10,960)
Basic and diluted net loss attributable to GMI per share of common stock (in dollars per share)	$ (0.07)	$ (0.16)	$ (0.12)
Weighted average number of shares outstanding - basic and diluted (in shares)	110,521	97,056	91,907
COMPREHENSIVE LOSS	$ (8,067)	$ (15,223)	$ (10,960)