Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Data Type:	xbrli:stringItemType
Balance Type:	na
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- Definition

The amount of interest that was capitalized during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 34
-Paragraph 21
-Subparagraph b

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Aggregate amount of interest paid or due on all long-term debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 8
-Article 9

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher OTS
-Name Federal Regulation (FR)
-Number Title 12
-Chapter V
-Section 563c.102
-Paragraph 8
-Subsection I

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount borrowed under the credit facility as of the balance-sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 22
-Article 5

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Net increase or decrease in the carrying amount of the debt instrument for the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph f
-Article 4

+ Details

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Period Type:	duration

LONG-TERM DEBT (Details) (USD $) In Millions	3 Months Ended		6 Months Ended		3 Months Ended
LONG-TERM DEBT (Details) (USD $) In Millions	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011 Credit Facilities	Jun. 30, 2010 Credit Facilities	Dec. 31, 2010 Credit Facilities
Debt instrument
Amount repaid of the credit facility during the period						$ 600
Amount drawn down on the credit facility							50
Long-term debt interest costs	10.3	15.3	20.3	19.8
Interest costs capitalized for property, plant and mine development	$ 0.2		$ 0.2	$ 4.6