SECURITIES AND EXCHANGE COMMISSION

FORM 8-K/A

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the
Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): October 14, 2004 (July 31, 2004)

Arch Coal, Inc.

One CityPlace Drive, Suite 300, St. Louis, Missouri 63141

Registrant’s telephone number, including area code: (314) 994-2700

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2.):

[  ] Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

[  ] Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

[  ] Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

[  ] Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Table of Contents

Item 2.01 Completion of Acquisition or Disposition of Assets

     On July 31, 2004, Arch Coal, Inc. (the “Company”) consummated its purchase of the 35% membership interest in Canyon Fuel Company, LLC (“Canyon Fuel”) owned by Itochu Coal International Inc, for a contract price of $112 million, financed as described below. The amount of the consideration was determined through arm’s length negotiation. The remaining 65% membership interest in Canyon Fuel is held by the Company’s subsidiary, Arch Western Bituminous Group LLC. The source of funds used to effect the cash portion of the purchase price was the Company’s working capital.

     The Company hereby amends its Current Report on Form 8-K originally filed with the United States Securities and Exchange Commission (the “SEC”) on August 13, 2004 relating to the acquisition of the 35% membership interest in Canyon Fuel to include the financial statements of the business acquired, the pro forma financial information and related exhibits as set forth below. The pro forma financial information set forth below gives effect to (i) the Company’s acquisition of the 35% membership interest in Canyon Fuel and (ii) the Company’s acquisition of Vulcan Coal Holdings, L.L.C. (“Vulcan”) and sale of Vulcan’s Buckskin mine, as described in the Company’s Current Report on Form 8-K filed with the SEC on August 24, 2004.

Item 9.01 Financial Statements, Pro Forma Financial Information and Exhibits.

     (a) Financial statements of business acquired.

     The Company hereby incorporates by reference the audited consolidated financial statements of Canyon Fuel for the year ended December 31, 2003, including the auditor’s report and notes included therein, that are included in Exhibit 99.1 of the Company’s Annual Report on Form 10-K for the Company’s fiscal year ended December 31, 2003.

     (b) Pro forma financial information (Unaudited)

     (c) Exhibits.

Canyon Fuel Company, LLC

Condensed Balance Sheet

Unaudited

(In thousands)

See notes to condensed financial statements.

F-1

Canyon Fuel Company, LLC

Condensed Statements of Operations

Unaudited

(In thousands)

See notes to condensed financial statements.

F-2

Canyon Fuel Company, LLC

Condensed Statements of Cash Flows

Unaudited

(In thousands)

See notes to condensed financial statements.

F-3

Canyon Fuel Company, LLC

Notes to Condensed Financial Statements (Unaudited)

June 30, 2004

1. The Company

The accompanying unaudited Condensed Financial Statements have been prepared in accordance with generally accepted accounting principles for interim financial reporting and Securities and Exchange Commission regulations, but are subject to any year-end adjustments that may be necessary. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. Results of operations for the period ended June 30, 2004 are not necessarily indicative of results to be expected for the year ending December 31, 2004. These financial statements should be read in conjunction with the audited financial statements and related notes thereto as of and for the year ended December 31, 2003 included in Arch Coal, Inc.’s Annual Report on Form 10-K as filed with the Securities and Exchange Commission.

Canyon Fuel Company, LLC (the Company) is a joint venture between Arch Western Resources, LLC (Arch Western) (65% ownership as of June 30, 2004) and ITOCHU Coal International Inc. (ITOCHU) (35% ownership as of June 30, 2004). The owners of the Company are referred to herein as the “Members.” Subsequent to June 30, 2004, Arch Coal, Inc. (Arch Coal) acquired ITOCHU’s 35% membership interest.

The Company operates one reportable segment: the production of steam coal from deep mines in Utah for sale primarily to utility companies in the United States. Net profits and losses and distributions of the Company’s earnings are allocated to the Members based on their respective ownership percentage.

During the first half of 2004, the Company idled its Skyline Mine and incurred severance costs of $3.2 million for the six months ended June 30, 2004. The Company anticipates increasing production from its other two mines to make up a portion of the scheduled production decrease associated with the idling.

2. Asset Retirement Obligations

On January 1, 2003, the Company adopted Statement of Financial Accounting Standards No. 143, Accounting for Asset Retirement Obligations (FAS 143). FAS 143 requires legal obligations associated with the retirement of long-lived assets to be recognized at fair value at the time the obligations are incurred. Upon initial recognition of a liability, that cost should be capitalized as part of the related long-lived asset and allocated to expense over the useful life of the asset. Previously, the Company accrued for the expected costs of these obligations over the estimated useful mining life of the property.

F-4

Canyon Fuel Company, LLC

Notes to Condensed Financial Statements (Unaudited) (Continued)

June 30, 2004

2. Asset Retirement Obligations (continued)

The cumulative effect of the change on prior years resulted in a charge to income of $2.4 million, which is included in the Company’s results of operations for the six months ended June 30, 2003.

The following table describes the changes to the Company’s asset retirement obligation for the six months ended June 30, 2004 and 2003:

3. Other Comprehensive Income

Comprehensive income represents changes in Members’ equity from non-owner sources. For the period ended June 30, 2004, minimum pension liability adjustments were the only item of other comprehensive income.

F-5

Canyon Fuel Company, LLC

Notes to Condensed Financial Statements (Unaudited) (Continued)

June 30, 2004

4. Employee Benefit Plans

Defined Benefit Pension and Other Postretirement Benefit Plans

Essentially all of the Company’s employees are covered by a defined benefit pension plan sponsored by the Company. The benefits are based on years of service and the employee’s compensation, primarily during the last five years of service. The funding policy for the pension plan is to make annual contributions as required by applicable regulations.

The Company also provides certain postretirement medical and life insurance benefits to substantially all employees who retire with the Company. The Company has the right to modify the plans at any time. The Company’s current policy is to fund the cost of postretirement medical and life insurance benefits as they are paid.

Components of Net Periodic Benefit Cost

The following table details the components of pension and other postretirement benefit costs:

* The Company does not fund its other postretirement liabilities.

F-6

Canyon Fuel Company, LLC

Notes to Condensed Financial Statements (Unaudited) (Continued)

June 30, 2004

4. Employee Benefit Plans (continued)

Cash Flows

The Company previously disclosed in its financial statements for the year ended December 31, 2003 that it expected to contribute approximately $3.3 million to its pension plan in 2004. During the period ended June 30, 2004, the Company contributed approximately $1.3 million to the plan. The Company presently anticipates contributing additional amounts of approximately $2.0 million to the pension plan in the second half of 2004.

Impact of Medicare Prescription Drug, Improvement and Modernization Act of 2003

On December 8, 2003, the President signed into law the Medicare Prescription Drug, Improvement and Modernization Act of 2003 (the Act). The Act introduces a prescription drug benefit under Medicare (Medicare Part D) as well as a federal subsidy to sponsors of retiree heath care benefit plans that provide a benefit that is at least actuarially equivalent to Medicare Part D. In May 2004, the Financial Accounting Standards Board issued FASB Staff Position FAS 106-2, Accounting and Disclosure Requirements related to the Medicare Prescription Drug, Improvement and Modernization Act of 2003 (“FSP 106-2”). The Company has included the effects of the Act in its financial statements for the quarter ending June 30, 2004 in accordance with FSP 106-2. Implementation of FSP 106-2 did not result in a material change in the Company’s postretirement benefit obligation or its anticipated postretirement medical expenses.

5. Inventories

Inventories consist of the following:

F-7

Canyon Fuel Company, LLC

Notes to Condensed Financial Statements (Unaudited) (Continued)

June 30, 2004

6. Related Party Transactions

As described in Note 1, 65% of the Company is owned by Arch Western. Arch Western acts as the Company’s managing Member. The Company pays administration and production fees to Arch Western for managing the Company’s operations. These fees were $4.1 million and $4.4 million for the six months ended June 30, 2004 and 2003, respectively. The Company has a payable balance to its Members of $6.4 million at June 30, 2004.

7. Contingencies

The Company is the subject of or party to a number of pending or threatened legal actions. On the basis of management’s best assessment of the likely outcome of these actions, expenses or judgments arising from any of these suits are not expected to have a material adverse effect on the Company’s operations, financial position or cash flows.

The Company is not aware of any events of noncompliance with environmental laws and regulations. The exact nature of environmental issues and costs, if any, which the Company may encounter in the future cannot be predicted, primarily because of the changing character of environmental requirements that may be enacted by governmental agencies.

8. Reclassifications

Certain amounts in the prior years’ financial statements have been reclassified to conform to the classifications in the current year’s financial statements with no effect on previously reported net income or members’ equity.

F-8

Arch Coal, Inc.

Pro Forma Background and Introduction (Unaudited)

BASIS OF PRESENTATION

On July 31, 2004, Arch Coal acquired a 35% interest in Canyon Fuel Company, LLC (“Canyon Fuel”) for a contract price of $112 million. Prior to this acquisition, Canyon Fuel was a joint venture owned 65% by Arch Western Resources, LLC (a subsidiary of Arch Coal) and 35% by ITOCHU Coal International Inc. The contract price was paid in the form of cash of $90 million paid upon closing and a five-year, $22 million non-interest bearing note. The present value of the obligation under the note totals $18.2 million.

On August 20, 2004, Arch Coal acquired (1) Vulcan Coal Holdings, L.L.C., which owns all of the common equity of Triton Coal Company, LLC (“Triton”), and (2) all of the preferred units of Triton, for an aggregate purchase price of $376.0 million, including acquisition costs. The final purchase price is subject to a working capital adjustment. Prior to the acquisition, Triton operated two mines (North Rochelle and Buckskin) in the Powder River Basin in Wyoming. Upon acquisition, Arch Coal sold the Buckskin mine to Peter Kiewet and Sons’ Inc. for $72.9 million. The net purchase price was financed with cash on hand, the proceeds from a $100 million term loan, and borrowings under Arch Coal’s revolving credit facility.

The acquisitions will be accounted for under the purchase method of accounting in accordance with FASB Statement No. 141. Under the purchase method of accounting, the purchase price is allocated to the assets acquired and liabilities assumed based on their estimated fair values. The accompanying unaudited pro forma condensed consolidated financial information reflects the combination of Arch Coal’s historical assets and liabilities (including its 65% investment in Canyon Fuel), the fair value of the 35% interest in the assets and liabilities of Canyon Fuel, and the fair value of the acquired assets and liabilities of Vulcan. The fair values of the acquired assets and liabilities are based on Arch Coal management’s preliminary estimates. These estimates are subject to change pending a final analysis of the value of the assets acquired and liabilities assumed. Arch Coal management is in the process of obtaining independent appraisals of the value of the assets acquired and liabilities assumed. The amounts assigned to certain assets and liabilities, including inventories, property, plant and equipment (including mineral reserves), and sales contracts are subject to change pending the results of the appraisals.

Prior to the acquisition of the 35% interest of Canyon Fuel, Arch Coal accounted for its 65% interest under the equity method due to certain super-majority voting rights in Canyon Fuel’s joint venture agreement. Arch Coal’s equity investment in Canyon Fuel included purchase adjustments primarily related to reductions in amounts assigned to sales contracts, mineral reserves and other property, plant and equipment. These adjustments are reflected in the column “Effect of Arch Coal’s Historical Basis” in the accompanying pro forma financial information.

P-1

Arch Coal, Inc.

Pro Forma Background and Introduction (Unaudited) (Continued)

The unaudited pro forma condensed combined financial statements are presented based on the assumption and adjustments described in the accompanying notes. The unaudited pro forma condensed combined statements of operations do not purport to represent what Arch Coal’s results of operations actually would have been if the events described above had occurred as of the dates indicated or what such results would be for any future periods. Pro forma adjustments to the unaudited pro forma condensed combined financial statements do not reflect potential cost saving opportunities, including the elimination of duplicative selling, general and administrative expenses.

PRO FORMA ADJUSTMENTS

Canyon Fuel Company

P-2

Arch Coal, Inc.

Pro Forma Background and Introduction (Unaudited) (Continued)

P-3

Arch Coal, Inc.

Pro Forma Background and Introduction(Unaudited) (Continued)

CONFORMING AND RECLASSIFICATION ADJUSTMENTS

There were no material adjustments required to conform the accounting policies of Arch Coal and Canyon Fuel. Certain amounts have been reclassified to conform to Arch Coal’s financial statement presentation.

Vulcan Coal Holdings

P-4

Arch Coal, Inc.

Pro Forma Background and Introduction(Unaudited) (Continued)

P-5

Arch Coal, Inc.

Pro Forma Background and Introduction(Unaudited) (Continued)

P-6

Arch Coal, Inc.

Pro Forma Background and Introduction (Unaudited) (Continued)

CONFORMING AND RECLASSIFICATION ADJUSTMENTS

Except as noted in (13) above, there were no material adjustments required to conform the accounting policies of Arch Coal and Vulcan. Certain amounts have been reclassified to conform to Arch Coal’s financial statement presentation.

P-7

Arch Coal, Inc.

Unaudited Pro Forma Condensed Consolidated Balance Sheet

June 30, 2004
(In thousands)

P-8

Arch Coal, Inc.

Unaudited Pro Forma Condensed Consolidated Balance Sheet

June 30, 2004
(In thousands)

P-9

Arch Coal, Inc.

Unaudited Pro Forma Condensed Consolidated Statements of Operations

For the Six Months Ended June 30, 2004
(In thousands, except per share data)

P-10

Arch Coal, Inc.

Unaudited Pro Forma Condensed Consolidated Statements of Operations

For the Year Ended December 31, 2003
(In thousands, except per share data)