SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                           ----------------------------

                                    FORM 8-K

                                 CURRENT REPORT

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


Date of Report (Date of earliest event reported): August 17, 2004
                                                             (August 16, 2004)

                                 Arch Coal, Inc.
             (Exact name of registrant as specified in its charter)

     Delaware                       1-13105                    43-0921172
----------------------------  ----------------------           ----------
(State or other jurisdiction (Commission File Number)        (I.R.S. Employer
    of incorporation)                                      Identification No.)


            One CityPlace Drive, Suite 300, St. Louis, Missouri 63141
               (Address of principal executive offices) (Zip code)


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











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Item 5. Other  Events.

     On August 13, 2004,  Arch Coal, Inc. (the  "Company"),  announced via press
release that the U.S.  District Court for the District of Columbia  rejected the
Federal Trade  Commission's  request for a preliminary  injunction  blocking the
Company's  acquisition  of Triton Coal Company.  A copy of the  Company's  press
release is attached hereto and incorporated herein by reference in its entirety.



Item 7.  Exhibits.

         (c) The following Exhibit is filed with this Current Report on Form
              8-K:

             Exhibit No.            Description
                99                    Press Release dated as of August 13, 2004


























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                                   SIGNATURES

     Pursuant to the  requirements  of the Securities  Exchange Act of 1934, the
registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned hereunto duly authorized.

Dated:  August 17, 2004                 ARCH COAL, INC.



                                       By:      /s/ Janet L.Horgan
                                          --------------------------------------
                                             Janet L. Horgan
                                             Assistant General Counsel and
                                               Assistant Secretary



























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                                  EXHIBIT INDEX


Exhibit No.                 Description
-----------                ------------
   99                       Press Release dated as of August 13, 2004


































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                                                                     Exhibit 99
News from
Arch Coal, Inc.
--------------------------------------------------------------------------------
                                                        FOR FURTHER INFORMATION:
                                                                      Deck Slone
                                                                  Vice President
                                           Investor Relations and Public Affairs
                                                                  (314) 994-2717

                                                           FOR IMMEDIATE RELEASE
                                                                 August 13, 2004

Arch Coal Comments on Favorable Decision in U.S. District Court
Concerning Triton Acquisition

     ST. LOUIS (August 13, 2004) - Late this afternoon,  the U.S. District Court
for the District of Columbia rejected the Federal Trade Commission's request for
a preliminary injunction blocking Arch's acquisition of Triton Coal Company.

     "We are  pleased  that  the  court  has  found no  cause  to  prevent  this
transaction  from moving  forward,"  said Steven F. Leer,  Arch's  president and
chief executive officer. "We are confident that completing this acquisition will
create  significant  benefits for our customers,  the end users of  electricity,
employees at both companies, and our shareholders."

     James M. Hake, president and chief executive officer of Triton, stated: "We
are very pleased that the court found no reason to enjoin our transaction, which
we believe to be in the best interests of Triton and its shareholders, customers
and other constituents."

     The Federal Trade Commission has the right to seek an emergency stay of the
District  Court's  decision.  Arch has agreed not to close the transaction for a
period of two full business days.

     Arch Coal,  Inc.  (NYSE:ACI) is one of the nation's  largest coal producers
and mines  clean-burning,  low-sulfur coal  exclusively.  Through its subsidiary
operations in West Virginia,  Kentucky,  Virginia,  Wyoming,  Colorado and Utah,
Arch Coal provides the fuel for approximately 6% of the electricity generated in
the United States.

     Forward-Looking Statements:  Statements in this press release which are not
statements of historical fact are  forward-looking  statements  within the "safe
harbor" provision of the Private Securities Litigation Reform Act of 1995. These
forward-looking  statements are based on information currently available to, and
expectations and assumptions  deemed  reasonable by, the company.  Because these
forward-looking  statements  are  subject  to various  risks and  uncertainties,
actual results may differ  materially  from those  projected in the  statements.
These  expectations,   assumptions  and  uncertainties  include:  the  company's
expectation  of  continued  growth  in  the  demand  for  electricity;  expected
synergies   resulting  from  the   acquisition;   belief  that  legislation  and
regulations  relating to the Clean Air Act and the  relatively  higher  costs of
competing  fuels will increase  demand for its compliance  and low-sulfur  coal;
expectation of improved  market  conditions  for the price of coal;  expectation
that the company will  continue to have  adequate  liquidity  from its cash flow
from operations, together with available borrowings under its credit facilities,
to finance  the  company's  working  capital  needs;  a variety of  operational,
geologic, permitting, labor and weather related factors; and the other risks and
uncertainties  which are described  from time to time in the  company's  reports
filed with the Securities and Exchange Commission.