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SIGNIFICANT JUDGMENTS, ESTIMATES AND ASSUMPTIONS (Details)
 12 Months Ended
Dec. 31, 2020
USD ($)
$ / oz
$ / bbl
Dec. 31, 2019
$ / oz
$ / bbl
Estimated price of gold per ounce (year 1) $ 1,700  
Estimated price of gold per ounce (year 2) 1,700  
Estimated price of gold per ounce (year 3) $ 1,500  
Estimated short-term and long-term prices of gold | $ / oz   1,400
Estimated short-term and long-term prices of silver | $ / oz 20 17.50
Estimated short-term and long-term oil prices | $ / bbl 55 60
Minimum | CGU    
Cash flow projection, term 4 years  
Real discount rate 3.61% 3.33%
NAV multiples observed 0.4 0.8
Maximum | CGU    
Cash flow projection, term 17 years  
Real discount rate 6.82% 6.97%
NAV multiples observed 1.5 1.7