Related Party Transactions	6 Months Ended
Related Party Transactions	Jun. 30, 2011
Related Party Transactions
Related Party Transactions	7. Related Party Transactions Transactions with Arch Coal may not be at arm's length. If the transactions were negotiated with an unrelated party, the impact could be material to the Company's results of operations. The Company's cash transactions are managed by Arch Coal. Cash paid to or from the Company that is not considered a distribution or a contribution is recorded in an Arch Coal receivable account. In addition, any amounts owed between the Company and Arch Coal, exclusive of borrowings under the intercompany credit agreement, are recorded in the account. At June 30, 2011 and December 31, 2010, the receivable from Arch Coal was approximately $1.6 billion and $1.5 billion, respectively. This amount earns interest from Arch Coal at the prime interest rate. Interest earned on the note was $13.3 million and $13.9 million for the three months ended June 30, 2011 and 2010, respectively, and $26.1 million and $25.8 million for the six months ended June 30, 2011 and 2010, respectively. The current portion of the receivable balance at June 30, 2011 and December 31, 2010, represents the amounts needed to fund working capital and contractual purchase, service and lease obligations due within the next twelve months. During September of 2010, the Company received a loan of $225.0 million and a repayment of a portion of the balance receivable from Arch Coal to redeem $500.0 million aggregate principal amount of the outstanding 6.75% senior notes at a redemption price of 101.125%. Interest incurred on the loan was $1.6 million for the three months ended June 30, 2011 and $3.2 million for the six months ended June 30, 2011. The Company is a party to Arch Coal's accounts receivable securitization program. Under the program, the Company sells its receivables to Arch Coal without recourse at a discount based on the prime rate and days sales outstanding. During the three months ended June 30, 2011 and 2010, the Company sold $431.7 million and $405.5 million, respectively, of trade accounts receivable to Arch Coal at a discount of $1.0 million for both periods. During the six months ended June 30, 2011 and 2010, the Company sold $828.9 million and $817.3 million, respectively, of trade accounts receivable to Arch Coal at a discount of $1.8 million and $1.9 million, respectively. For the three months ended June 30, 2011 and 2010, the Company incurred production royalties of $24.9 million and $20.8 million, respectively, under sublease agreements with Arch Coal. For the six months ended June 30, 2011 and 2010, the Company incurred production royalties of $49.6 million and $38.9 million, respectively, under sublease agreements with Arch Coal. The Company is charged selling, general and administrative services fees by Arch Coal. Expenses are allocated based on Arch Coal's best estimates of proportional or incremental costs, whichever is more representative of costs incurred by Arch Coal on behalf of the Company. Amounts allocated to the Company by Arch Coal were $8.3 million and $11.4 million for the three months ended June 30, 2011 and 2010, respectively and $17.6 million and $19.2 million for the six months ended June 30, 2011 and 2010, respectively. Such amounts are reported as selling, general and administrative expenses in the accompanying condensed consolidated statements of income.

The entire disclosure for related party transactions, including the nature of the relationship(s), a description of the transactions, the amount of the transactions, the effects of any change in the method of establishing the terms of the transaction from the previous period, stated interest rate, expiration date, terms and manner of settlement per the agreement with the related party, and amounts due to or from related parties. If the entity and one or more other entities are under common ownership or management control and this control affects the operating results or financial position, disclosure includes the nature of the control relationship even if there are no transactions between the entities. Disclosure may also include the aggregate amount of current and deferred tax expense for each statement of earnings presented where the entity is a member of a group that files a consolidated tax return, the amount of any tax related balances due to or from affiliates as of the date of each statement of financial position presented, the principal provisions of the method by which the consolidated amount of current and deferred tax expense is allocated to the members of the group and the nature and effect of any changes in that method. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(k))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 3A
-Section 04
-Paragraph b

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 57
-Paragraph 1-4
-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.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
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-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39678-107864

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
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Reference 6: http://www.xbrl.org/2003/role/presentationRef
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 8: http://www.xbrl.org/2003/role/presentationRef
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 850
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39603-107864

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ARCH WESTERN RESOURCES LLC 10-Q