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Environmental And Mine Closure Obligations (Asset Retirement Obligation Disclosure) (Detail) (USD $)
In Millions, unless otherwise specified |
6 Months Ended | 12 Months Ended | ||||
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Jun. 30, 2012
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Dec. 31, 2011
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| Asset Retirement Obligations [Line Items] | ||||||
| Asset retirement obligation at beginning of period | $ 203.7 | [1] | $ 168.3 | [1] | ||
| Accretion expense | 8.9 | 16.1 | [1] | |||
| Exchange rate changes | 0.1 | 0.1 | [1] | |||
| Revision in estimated cash flows | 5.9 | [1] | ||||
| Payments | (0.7) | [1] | ||||
| Acquired through business combinations | 14.0 | [1] | ||||
| Asset retirement obligation at end of period | $ 212.7 | $ 203.7 | [1] | |||
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- Definition
Acquired through business combinations No definition available.
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- Details
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- Definition
The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount of the Increase or Decrease in the amount of asset retirement obligations for the period associated with foreign currency translation (to the extent that the entity accounts for the foreign currency effects as a separate component of the change in the liability). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount of asset retirement obligations settled, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount of the Increase or Decrease in the amount of the asset retirement obligation during the current period for changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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