REVENUE: - Provisionally prices sales (Details) lb in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2021 USD ($) lb $ / item
Copper
Provisionally priced sales:
Provisional price sales adjustment amounts included in accounts receivable and net sales | $	$ 30.7
Copper | October 2021 Through February 2022
Provisionally priced sales:
Sales volume (in million lbs.) | lb	174.1
Provisional price | $ / item	4.06
Molybdenum
Provisionally priced sales:
Provisional price sales adjustment amounts included in accounts receivable and net sales | $	$ 8.2
Molybdenum | October 2021 Through December 2021
Provisionally priced sales:
Sales volume (in million lbs.) | lb	15.3
Provisional price | $ / item	18.45