PROVISIONALLY PRICED SALES: (Details)	Jun. 30, 2011 lbs
Copper
Provisionally priced sales
Nonmonetary notional amount of commodity (in million lbs.)	75,500,000
Provisional price	4.27
Copper | July 2011
Provisionally priced sales
Nonmonetary notional amount of commodity (in million lbs.)	50,100,000
Provisional price	4.27
Copper | August 2011
Provisionally priced sales
Nonmonetary notional amount of commodity (in million lbs.)	25,400,000
Provisional price	4.28
Molybdenum
Provisionally priced sales
Nonmonetary notional amount of commodity (in million lbs.)	9,000,000
Provisional price	15.55
Molybdenum | July 2011
Provisionally priced sales
Nonmonetary notional amount of commodity (in million lbs.)	2,900,000
Provisional price	15.55
Molybdenum | August 2011
Provisionally priced sales
Nonmonetary notional amount of commodity (in million lbs.)	3,400,000
Provisional price	15.55
Molybdenum | September 2011
Provisionally priced sales
Nonmonetary notional amount of commodity (in million lbs.)	2,400,000
Provisional price	15.55
Molybdenum | October 2011
Provisionally priced sales
Nonmonetary notional amount of commodity (in million lbs.)	300,000
Provisional price	15.55