SECURITIES AND EXCHANGE COMMISSION
                              Washington, DC 20549

                                 SCHEDULE 13G/A
                                 (Rule 13d-102)

           INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO
            RULES 13d-1(b), (c) AND (d) AND AMENDMENTS THERETO FILED
                            PURSUANT TO RULE 13d-2(b)

                                (Amendment No. 1)


                                 ARCH COAL, INC.
--------------------------------------------------------------------------------
                                (Name of Issuer)


                Shares of Common Stock, par value $.01 per share
--------------------------------------------------------------------------------
                         (Title of Class of Securities)


                                    039380100
--------------------------------------------------------------------------------
                                 (CUSIP Number)


                                December 31, 2002
--------------------------------------------------------------------------------
             (Date of Event Which Requires Filing of this Statement)


Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

[ ] Rule 13d-1(b)
[X] Rule 13d-1(c)
[ ] Rule 13d-1(d)



                                       1


CUSIP No. 039380100                  13G/A


      1        NAME OF REPORTING PERSONS
               I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

               Greenlight Capital, L.L.C.
--------------------------------------------------------------------------------
      2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*     (a) [  ]
                                                                     (b) [  ]
--------------------------------------------------------------------------------
      3        SEC USE ONLY

--------------------------------------------------------------------------------
      4        CITIZENSHIP OR PLACE OF ORGANIZATION

               Delaware
--------------------------------------------------------------------------------
                                5        SOLE VOTING POWER

                                         2,779,600
                                ------------------------------------------------
         NUMBER OF              6        SHARED VOTING POWER
           SHARES
        BENEFICIALLY                     0
          OWNED BY              ------------------------------------------------
            EACH                7        SOLE DISPOSITIVE POWER
         REPORTING
        PERSON WITH                      2,779,600
                                ------------------------------------------------
                                8        SHARED DISPOSITIVE POWER

                                         0
--------------------------------------------------------------------------------
      9        AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

               2,779,600
--------------------------------------------------------------------------------
     10        CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
               SHARES*
                                                                          [  ]
--------------------------------------------------------------------------------
     11        PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

               5.3% **
--------------------------------------------------------------------------------
     12        TYPE OF REPORTING PERSON*

               CO


         *SEE INSTRUCTIONS BEFORE FILLING OUT
         **SEE ITEM 4(b).


                                       2


CUSIP No. 039380100                  13G/A


      1        NAME OF REPORTING PERSONS
               I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

               David Einhorn
--------------------------------------------------------------------------------
      2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*       (a) [  ]
                                                                       (b) [  ]
--------------------------------------------------------------------------------
      3        SEC USE ONLY

--------------------------------------------------------------------------------
      4        CITIZENSHIP OR PLACE OF ORGANIZATION

               U.S. Citizen
--------------------------------------------------------------------------------
                                5        SOLE VOTING POWER

                                         2,779,600
                                ------------------------------------------------
         NUMBER OF              6        SHARED VOTING POWER
           SHARES
        BENEFICIALLY                     0
          OWNED BY              ------------------------------------------------
            EACH                7        SOLE DISPOSITIVE POWER
         REPORTING
        PERSON WITH                      2,779,600
                                ------------------------------------------------
                                8        SHARED DISPOSITIVE POWER

                                         0
--------------------------------------------------------------------------------
      9        AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

               2,779,600
--------------------------------------------------------------------------------
     10        CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
               SHARES*
                                                                          [  ]
--------------------------------------------------------------------------------
     11        PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

               5.3% **
--------------------------------------------------------------------------------
     12        TYPE OF REPORTING PERSON*

               IN


         *SEE INSTRUCTIONS BEFORE FILLING OUT
         **SEE ITEM 4(b).


                                       3



                         AMENDMENT NO. 1 TO SCHEDULE 13G

         This Schedule 13G (the "Schedule 13G"), relating to shares of common
stock of Arch Coal, Inc., a Delaware corporation (the "Issuer"), is being filed
with the Securities and Exchange Commission (the "Commission") as an amendment
to Schedule 13G filed with the Commission on August 16, 2002. This Schedule 13G
is being filed on behalf of Greenlight Capital, L.L.C., a Delaware limited
liability company ("Greenlight"), and Mr. David Einhorn, principal of
Greenlight.

         This Schedule 13G relates to shares of Common Stock of the Issuer
purchased by Greenlight for the account of (i) Greenlight Capital, L.P.
("Greenlight Fund"), of which Greenlight is the general partner, (ii) Greenlight
Capital Qualified, L.P. ("Greenlight Qualified"), of which Greenlight is the
general partner and (iii) Greenlight Capital Offshore, Ltd. ("Greenlight
Offshore"), to which Greenlight acts as investment advisor.

ITEM 2(a)         NAME OF PERSON FILING.

                  Greenlight and David Einhorn.

ITEM 2(c)         CITIZENSHIP OR PLACE OF ORGANIZATION.

                  Greenlight is a limited liability company organized under the
                  laws of the State of Delaware. David Einhorn is the principal
                  of Greenlight and a United States citizen.

ITEM 4            OWNERSHIP.

                  (a)      Greenlight and Mr. Einhorn are the beneficial owners
                           of 2,779,600 shares of Common Stock.

                  (b)      Greenlight and Mr. Einhorn are the beneficial owners
                           of 5.3% of the outstanding shares of Common Stock.
                           This percentage is determined by dividing 2,779,600
                           by 52,382,010, the number of shares of Common Stock
                           issued and outstanding as of November 1, 2002, as
                           reported in the Issuer's quarterly report on Form
                           10-Q filed November 14, 2002.

                  (c)      Greenlight has the sole power to vote and dispose of
                           the 2,779,600 shares of Common Stock beneficially
                           owned by it. As the principal of Greenlight, Mr.
                           Einhorn may direct the vote and disposition of the
                           2,779,600 shares of Common Stock beneficially owned
                           by Greenlight.

ITEM 10           CERTIFICATION.

                  By signing below I certify that, to the best of my knowledge
                  and belief, the securities referred to above were not acquired
                  and are not held for the purpose of or with the effect of
                  changing or influencing the control of the issuer of the
                  securities and were not acquired and are not held in
                  connection with or as a participant in any transaction having
                  that purpose or effect.


                                       4


EXHIBITS          EXHIBIT 1

                  Joint Filing Agreement dated March 13, 2003, between
                  Greenlight and David Einhorn.




                                       5



                                    SIGNATURE

         After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.


         Date:  March 13, 2003

                                  Greenlight Capital, L.L.C.


                                  By: /s/ DAVID EINHORN
                                      -------------------------------
                                      David Einhorn, Managing Member



                                  /s/ DAVID EINHORN
                                  -----------------------------------
                                  David Einhorn




                                       6


                               INDEX TO EXHIBITS




EXHIBIT
NUMBER            DESCRIPTION
---------         -------------------------------------------------------------
               
Exhibit 1         Joint Filing Agreement dated March 13, 2003, between
                  Greenlight and David Einhorn.




                                       7