Property, Plant, Equipment and Mineral Rights and Reserves (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Property plant equipment and mineral rights and reserves
Mineral rights and reserves	$ 48.6	$ 52.5
Land	13.0	12.1
Buildings and improvements	104.9	97.5
Machinery and equipment	414.5	362.0
Construction in progress	32.6	25.2
Gross property, plant and equipment	$ 613.6	$ 549.3

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Amount before accumulated depreciation of building structures held for productive use including addition, improvement, or renovation to the structure, including, but not limited to, interior masonry, interior flooring, electrical, and plumbing.

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Gross amount, at the balance sheet date, of long-lived assets under construction that include construction costs to date on capital projects that have not been completed and assets being constructed that are not ready to be placed into service.

+ References

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Carrying amount as of the balance sheet date of real estate held for productive use. This excludes land held for sale.

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Gross amount, as of the balance sheet date, of long-lived, depreciable assets used in the production process to produce goods and services.

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Carrying amount at the balance sheet date of mineral rights, or rights to extract a mineral from the earth or to receive payment in the form of a royalty for the extraction of minerals, net of amortization.

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-Publisher FASB

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Gross amount of long-lived physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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