The charge against earnings in the period for known or estimated future costs arising from requirements to perform environmental remediation activities.

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+ Details

COMMITMENTS AND CONTINGENCIES: (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended	37 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2011 person category	Mar. 31, 2013
Environmental costs
Environmental capital expenditure	$ 11.2	$ 9.4
Peruvian operations
Environmental costs
Environmental capital expenditure	0.7	1.1
Mexican Operations
Environmental costs
Environmental capital expenditure	10.5	8.3
Number of categories of collective actions			3
Minimum number of people claiming injury due to collective action initiative in Civil Federal Procedures Code (CFPC)			30
Plant demolition and soil remediation budgeted cost				35.7
Plant demolition and soil cost recognized				$ 33.5