SUPPLEMENTARY MINERAL RESERVE INFORMATION (UNAUDITED) (Details) oz in Millions, lb in Millions	Dec. 31, 2016 USD ($) lb oz $ / lb
Copper
Estimated Recoverable Proven And Probable Reserves | lb	104,600
Long Term Average Price Used To Estimate Recoverable Reserves	$ 2.00
Three Year Average Price | $ / lb	2.60
Gold
Estimated Recoverable Proven And Probable Reserves | oz	37.6
Long Term Average Price Used To Estimate Recoverable Reserves	$ 1,000
Three Year Average Price | $ / lb	1,226
Molybdenum
Estimated Recoverable Proven And Probable Reserves | lb	2,990
Long Term Average Price Used To Estimate Recoverable Reserves	$ 10
Three Year Average Price | $ / lb	8.18
Silver
Long Term Average Price Used To Estimate Recoverable Reserves	$ 15