ACQUISITIONS (Details) $ in Thousands			1 Months Ended		9 Months Ended
	Mar. 30, 2020 USD ($)	Jan. 29, 2020 USD ($)	Nov. 30, 2019 USD ($)	Aug. 31, 2019 USD ($) payment	Mar. 31, 2020 USD ($) shares	Mar. 31, 2019 USD ($)	Aug. 31, 2019 $ / shares shares	Jun. 30, 2019 USD ($)
Acquisitions
Acquisition consideration paid					$ 107,855	$ 1,055
Investment value					$ 11,500			$ 16,000
TriStar
Acquisitions
Common stock that can be purchased by warrants (in shares) | shares					19,640,000
Alturas
Acquisitions
Acquisition consideration paid		$ 11,000
Future payment based on project decisions		20,000
Alturas | Maximum
Acquisitions
Acquisition consideration		41,000
Future payment to private individuals upon first production		$ 10,000
Alturas | Gold
Acquisitions
Net smelter return (NSR) (as a percent)		1.06%
Alturas | Copper
Acquisitions
Net smelter return (NSR) (as a percent)		1.59%
CDS
Acquisitions
Net smelter return (NSR) (as a percent)				1.50%
Acquisition consideration				$ 7,500
Acquisition consideration paid	$ 1,500		$ 1,500	$ 4,500
Number of installments | payment				3
Acquisition payment, excluding associated costs				$ 7,500
CDS | TriStar
Acquisitions
Common stock that can be purchased by warrants (in shares) | shares					19,640,000		19,640,000
Investment value					$ 300
Exercise price of warrants | $ / shares							$ 0.25
Term of warrants					5 years