ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS (Narrative) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Environmental Remediation Obligations [Abstract]
Total environmental and mine closure obligations	$ 169.0	$ 170.8

Environmental Loss Contingency And Mine Reclamation And Closing Liability Current And Noncurrent

No definition available.

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