XML 71 R50.htm IDEA: XBRL DOCUMENT v3.3.1.900
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES: (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2015
USD ($)
segment
item
$ / lb
Dec. 31, 2014
$ / lb
Dec. 31, 2013
$ / lb
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:      
Average estimated recovery period of long-term leach material 5 years    
Increase in total reserves at a property to qualify as a major expansion (as a percent) 10.00%    
Period considered for calculation of average metal price 3 years    
Current price of copper (in dollars per pound) | $ / lb 2.99 3.36 3.65
Impairment in the carrying value of long-term assets | $ $ 0.0    
Number of years of average prices for copper and molybdenum used for impairment analysis 3 years    
Number of reportable segments | segment 3    
Minimum      
Financial information related to segments      
Estimated useful lives of buildings and equipment 5 years    
Maximum      
Financial information related to segments      
Maximum period after shipping within which pricing is based by customer contracts in most cases 3 months    
Estimated useful lives of buildings and equipment 40 years    
Peruvian Operations      
Financial information related to segments      
Number of open-pit copper mines 2    
Mexican IMMSA Unit      
Financial information related to segments      
Number of underground poly metal mines 5