December 15, 2005

Mr. Robert Messey
Chief Financial Officer
Arch Coal, Inc.
One City Place Drive, Suite 300
St. Louis, MO  63141

	Re:	Arch Coal, Inc.
		Form 10-K for Fiscal Year Ended December 31, 2004
      Filed March 11, 2005
		Form 10-Q for Nine Months Ended September 30, 2005
      Filed November 9, 2005
		File No. 001-13105

Dear Mr. Messey:

      We have reviewed your filings and have the following
We have limited our review of your filings to those issues we have
addressed in our comments. Where indicated, we think you should
revise your documents.  If you disagree, we will consider your
explanation as to why our comment is inapplicable or a revision is
unnecessary.  Please be as detailed as necessary in your
In some of our comments, we may ask you to provide us with
information so we may better understand your disclosure.  After
reviewing this information, we may raise additional comments.

	Please understand that the purpose of our review process is
assist you in your compliance with the applicable disclosure
requirements and to enhance the overall disclosures in your
We look forward to working with you in these respects.  We welcome
any questions you may have about our comments or any other aspect
our review.  Feel free to call us at the telephone numbers listed
the end of this letter.

Form 10-K for the Fiscal Year Ended December 31, 2004

Financial Statements

Report of Independent Registered Public Accounting Firm, page II-

1. We note the language in your auditor`s report indicating the
of your financial statements was conducted in accordance with
auditing standards generally accepted in the United States,
reference to the PCAOB auditing standards.  Additionally, the
paragraph indicates that only two years have been audited, while
opening paragraph suggests the audit may cover all three years.
There appears to be some inconsistency between this report and the
audit opinion concerning your internal control over financial
reporting presented on page II-38.  Please consult with your
as to the actions that will be necessary to remedy these items and
for you to comply with the guidance in Rules 2-02 and 3-02 of
Regulation S-X.

Note 20 - Commitments and Contingencies, page II-78

2. We note your disclosure that you agreed to indemnify another
member of Arch Western against certain tax liabilities in the
such liabilities arise, and depending on timing of any such
indemnification obligation, it could have a material adverse
on your business, results of operations and financial condition.

Please expand your disclosure to include the information required
under FIN 45, paragraph 13, such as the term of your guarantee,
current carrying amount of any liability recorded, maximum
amount of future payments that you could be required to make under
your guarantee, and the nature of any recourse provisions.

Quarterly Financial Information, page II-82

3. Please expand your disclosure to include gross profit, as
by Item 302(a)(1) of Regulation S-K.  Please ensure that any
depreciation, depletion and amortization amounts attributable to
cost of sales are included in your gross profit measures.

Closing Comments

       As appropriate, please amend your filings and respond to
comments within 10 business days or tell us when you will provide
with a response.  You may wish to provide us with marked copies of
the amendment to expedite our review.  Please furnish a cover
with your amendment that keys your responses to our comments and
provides any requested information.  Detailed cover letters
facilitate our review.  Please understand that we may have
comments after reviewing your responses to our comments.

	We urge all persons who are responsible for the accuracy and
adequacy of the disclosures in the filings to be certain that the
filings include all information required under the Securities
Exchange Act of 1934 and that they have provided all information
investors require for an informed investment decision.  Since the
company and its management are in possession of all facts relating
a company`s disclosures, they are responsible for the accuracy and
adequacy of the disclosures they have made.

	In connection with responding to our comments, please
in writing, a statement from the company acknowledging that:

* the company is responsible for the adequacy and accuracy of the
disclosures in the filings;

* staff comments or changes to disclosures in response to staff
comments do not foreclose the Commission from taking any action
respect to the filings; and

* the company may not assert staff comments as a defense in any
proceeding initiated by the Commission or any person under the
federal securities laws of the United States.

      In addition, please be advised that the Division of
has access to all information you provide to the staff of the
Division of Corporation Finance in our review of your filings or
response to our comments on your filings.

	You may contact Lily Dang at (202) 551-3867 if you have
questions regarding comments on the financial statements and
matters.  Please contact me at (202) 551-3686 with any other


								Karl Hiller
								Branch Chief
Mr. Robert Messey
Arch Coal, Inc.
December 15, 2005
Page 1

WASHINGTON, D.C. 20549-7010