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                                                                     EXHIBIT 4.1

                                                                  EXECUTION COPY

                            ARCH WESTERN FINANCE, LLC

                          6 3/4% SENIOR NOTES DUE 2013

                          REGISTRATION RIGHTS AGREEMENT

                                                              New York, New York

                                                                October 22, 2004

Citigroup Global Markets Inc.
J.P. Morgan Securities Inc.
Morgan Stanley & Co. Incorporated
As Representatives of the Initial Purchasers
c/o Citigroup Global Markets Inc.
     388 Greenwich Street
     New York, New York 10013

Dear Sirs:

         Arch Western Finance, LLC, a limited liability company organized under
the laws of Delaware, and Arch of Wyoming, LLC,, a limited liability company
organized under the laws of Delaware (each an "Issuer", and together, the
"Issuers"), propose to issue and sell to certain purchasers (the "Initial
Purchasers"), upon the terms set forth in a Purchase Agreement dated October 19,
2004 (the "Purchase Agreement") relating to the initial placement (the "Initial
Placement") of the Issuer's 6 3/4% Senior Notes due 2013 (the "Notes"). The
Notes will be fully and unconditionally guaranteed as to payment of principal,
premium if any, and interest (the "Guarantees" and together with the Notes
hereinafter referred to as the "Securities") by Arch Western Resources, LLC, a
limited liability company organized under the laws of Delaware ("Arch Western")
and the Subsidiary Guarantors listed in Schedule II to the Purchase Agreement
and Arch Western Finance, LLC (collectively, the "Subsidiary Guarantors"). Arch
Western and the Subsidiary Guarantors are hereinafter referred to as the
"Guarantors". To induce the Initial Purchasers to enter into the Purchase
Agreement and to satisfy a condition of your obligations thereunder, each of the
Issuers, Arch Coal, Inc., a corporation organized under the laws of Delaware
(the "Company"), and the Guarantors, jointly and severally, agrees with you for
your benefit and the benefit of the holders from time to time of the Securities
(including the Initial Purchasers) (each a "Holder" and, together, the
"Holders"), as follows:

         1. Definitions. Capitalized terms used herein without definition shall
have their respective meanings set forth in the Purchase Agreement. As used in
this Agreement, the following capitalized defined terms shall have the following
meanings:

         "Act" shall mean the Securities Act of 1933, as amended, and the rules
and regulations of the Commission promulgated thereunder.


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         "Affiliate" of any specified Person shall mean any other Person that,
directly or indirectly, is in control of, is controlled by, or is under common
control with, such specified Person. For purposes of this definition, control of
a Person shall mean the power, direct or indirect, to direct or cause the
direction of the management and policies of such Person whether by contract or
otherwise; and the terms "controlling" and "controlled" shall have meanings
correlative to the foregoing.

         "Arch Western" shall have the meaning set forth in the preamble hereto.

         "Broker-Dealer" shall mean any broker or dealer registered as such
under the Exchange Act.

         "Business Day" shall mean any day other than a Saturday, a Sunday or a
legal holiday or a day on which banking institutions or trust companies are
authorized or obligated by law to close in New York City.

         "Commission" shall mean the Securities and Exchange Commission.

         "Company" shall have the meaning set forth in the preamble hereto.

         "Exchange Act" shall mean the Securities Exchange Act of 1934, as
amended, and the rules and regulations of the Commission promulgated thereunder.

         "Exchange Offer Registration Period" shall mean the one-year period
following the consummation of the Registered Exchange Offer, exclusive of any
period during which any stop order shall be in effect suspending the
effectiveness of the Exchange Offer Registration Statement.

         "Exchange Offer Registration Statement" shall mean a registration
statement of each of the Issuer and the Guarantors on an appropriate form under
the Act with respect to the Registered Exchange Offer, all amendments and
supplements to such registration statement, including post-effective amendments
thereto, in each case including the Prospectus contained therein, all exhibits
thereto and all material incorporated by reference therein.

         "Exchanging Dealer" shall mean any Holder (which may include any
Initial Purchaser) that is a Broker-Dealer and elects to exchange for New
Securities any Securities that it acquired for its own account as a result of
market-making activities or other trading activities (but not directly from the
Issuer or any Guarantor or any Affiliate of the Issuer or any Guarantor) for New
Securities.

         "Final Memorandum" shall have the meaning set forth in the Purchase
Agreement.

         "Guarantors" shall have the meaning set forth in the preamble hereto.

         "Holder" shall have the meaning set forth in the preamble hereto.


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         "Indenture" shall mean the Indenture relating to the Securities, dated
as of June 25, 2003, among each of the Issuer, the Guarantors and the Bank of
New York, as trustee, as the same may be amended from time to time in accordance
with the terms thereof.

         "Initial Placement" shall have the meaning set forth in the preamble
hereto.

         "Initial Purchaser" shall have the meaning set forth in the preamble
hereto.

         "Issuer" shall have the meaning set forth in the preamble hereto.

         "Losses" shall have the meaning set forth in Section 6(d) hereof.

         "Majority Holders" shall mean the Holders of a majority of the
aggregate principal amount of Securities registered under a Registration
Statement.

         "Managing Underwriters" shall mean the investment banker or investment
bankers and manager or managers that shall administer an underwritten offering.

         "New Securities" shall mean debt securities of the Issuers identical in
all material respects to the Securities (except that the cash interest and
interest rate step-up provisions and the transfer restrictions shall be modified
or eliminated, as appropriate) and to be issued under the Indenture or the New
Securities Indenture.

         "New Securities Indenture" shall mean an indenture among each of the
Issuers, the Guarantors and the New Securities Trustee, identical in all
material respects to the Indenture (except that the cash interest and interest
rate step-up provisions will be modified or eliminated, as appropriate).

         "New Securities Trustee" shall mean a bank or trust company reasonably
satisfactory to the Initial Purchasers, as trustee with respect to the New
Securities under the New Securities Indenture.

         "Notes" shall have the meaning set forth in the preamble hereto.

         "Prospectus" shall mean the prospectus included in any Registration
Statement (including, without limitation, a prospectus that discloses
information previously omitted from a prospectus filed as part of an effective
registration statement in reliance upon Rule 430A under the Act), as amended or
supplemented by any prospectus supplement, with respect to the terms of the
offering of any portion of the Securities or the New Securities covered by such
Registration Statement, and all amendments and supplements thereto and all
material incorporated by reference therein.

         "Purchase Agreement" shall have the meaning set forth in the preamble
hereto.

         "Registered Exchange Offer" shall mean the proposed offer of the
Issuers and the Guarantors to issue and deliver to the Holders of the Securities
that are not prohibited by any law or policy of the Commission from
participating in such offer, in exchange for the Securities, a like aggregate
principal amount of the New Securities.


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         "Registration Statement" shall mean any Exchange Offer Registration
Statement or Shelf Registration Statement that covers any of the Securities or
the New Securities pursuant to the provisions of this Agreement, any amendments
and supplements to such registration statement, including post-effective
amendments (in each case including the Prospectus contained therein), all
exhibits thereto and all material incorporated by reference therein.

         "Securities" shall have the meaning set forth in the preamble hereto.

         "Shelf Registration" shall mean a registration effected pursuant to
Section 3 hereof.

         "Shelf Registration Period" has the meaning set forth in Section 3(b)
hereof.

         "Shelf Registration Statement" shall mean a "shelf" registration
statement of the Issuers and the Guarantors pursuant to the provisions of
Section 3 hereof which covers some or all of the Securities or New Securities,
as applicable, on an appropriate form under Rule 415 under the Act, or any
similar rule that may be adopted by the Commission, amendments and supplements
to such registration statement, including post-effective amendments, in each
case including the Prospectus contained therein, all exhibits thereto and all
material incorporated by reference therein.

         "Subsidiary Guarantor" shall have the meaning set forth in the preamble
hereto.

         "Trustee" shall mean the trustee with respect to the Securities under
the Indenture.

         "underwriter" shall mean any underwriter of Securities in connection
with an offering thereof under a Shelf Registration Statement.

         2. (a) Unless prohibited under applicable law or policy of the
Commission, the Issuers, the Company and the Guarantors shall prepare and, not
later than 90 days following the date hereof (or if such 90th day is not a
Business Day, the next succeeding Business Day), the Issuers and the Guarantors
shall file with the Commission the Exchange Offer Registration Statement with
respect to the Registered Exchange Offer. The Issuers, the Company and the
Guarantors shall use their reasonable best efforts to cause the Exchange Offer
Registration Statement to become effective under the Act within 180 days of the
date hereof (or if such 180th day is not a Business Day, the next succeeding
Business Day).

         (b) Upon the effectiveness of the Exchange Offer Registration
Statement, the Issuers, the Company and the Guarantors shall promptly commence
the Registered Exchange Offer, it being the objective of such Registered
Exchange Offer to enable each Holder electing to exchange Securities for New
Securities (assuming that such Holder is not an Affiliate of the Issuers or any
Guarantor, acquires the New Securities in the ordinary course of such Holder's
business, has no arrangements with any Person to participate in the distribution
of the New Securities and is not prohibited by any law or policy of the
Commission from participating in the Registered Exchange Offer) to trade such
New Securities from and after their receipt without any limitations or
restrictions under the Act and without material restrictions under the
securities laws of a substantial proportion of the several states of the United
States.


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         (c) In connection with the Registered Exchange Offer, the Issuers, the
Company and the Guarantors shall:

                  (i) mail to each Holder a copy of the Prospectus forming part
         of the Exchange Offer Registration Statement, together with an
         appropriate letter of transmittal and related documents;

                  (ii) keep the Registered Exchange Offer open for not less than
         30 Business Days and not more than 45 Business Days after the date
         notice thereof is mailed to the Holders (or, in each case, longer if
         required by applicable law);

                  (iii) use their reasonable best efforts to keep the Exchange
         Offer Registration Statement continuously effective under the Act,
         supplemented and amended as required, under the Act to ensure that it
         is available for sales of New Securities by Exchanging Dealers during
         the Exchange Offer Registration Period;

                  (iv) utilize the services of a depositary for the Registered
         Exchange Offer with an address in the Borough of Manhattan in New York
         City, which may be the Trustee, the New Securities Trustee or an
         Affiliate of either of them;

                  (v) permit Holders to withdraw tendered Securities at any time
         prior to the close of business, New York time, on the last Business Day
         on which the Registered Exchange Offer is open;

                  (vi) prior to effectiveness of the Exchange Offer Registration
         Statement, provide a supplemental letter to the Commission (A) stating
         that the Issuers and the Guarantors are conducting the Registered
         Exchange Offer in reliance on the position of the Commission in Exxon
         Capital Holdings Corporation (pub. avail. May 13, 1988), Morgan Stanley
         and Co., Inc. (pub. avail. June 5, 1991); and (B) including a
         representation that each of the Issuers and the Guarantors has not
         entered into any arrangement or understanding with any Person to
         distribute the New Securities to be received in the Registered Exchange
         Offer and that, to the best of each of the Issuers' and the Guarantors'
         information and belief, each Holder participating in the Registered
         Exchange Offer is acquiring the New Securities in the ordinary course
         of business and has no arrangement or understanding with any Person to
         participate in the distribution of the New Securities; and

                  (vii) comply in all material respects with all applicable
         laws.

         (d) As soon as practicable after the close of the Registered Exchange
Offer, the Issuers and the Guarantors shall:

                  (i) accept for exchange all Securities tendered and not
         validly withdrawn pursuant to the Registered Exchange Offer;

                  (ii) deliver to the Trustee for cancellation in accordance
         with Section 4(s) all Securities so accepted for exchange; and


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                  (iii) cause the New Securities Trustee promptly to
         authenticate and deliver to each Holder of Securities a principal
         amount of New Securities equal to the principal amount of the
         Securities of such Holder so accepted for exchange.

         (e) Each Holder hereby acknowledges and agrees that any Broker-Dealer
and any such Holder using the Registered Exchange Offer to participate in a
distribution of the New Securities (x) could not under Commission policy as in
effect on the date of this Agreement rely on the position of the Commission in
Morgan Stanley and Co., Inc. (pub. avail. June 5, 1991) and Exxon Capital
Holdings Corporation (pub. avail. May 13, 1988), as interpreted in the
Commission's letter to Shearman & Sterling dated July 2, 1993 and similar
no-action letters; and (y) must comply with the registration and prospectus
delivery requirements of the Act in connection with any secondary resale
transaction must be covered by an effective registration statement containing
the selling security holder information required by Item 507 or 508, as
applicable, of Regulation S-K under the Act if the resales are of New Securities
obtained by such Holder in exchange for Securities acquired by such Holder
directly from the Company or one of its Affiliates. Accordingly, each Holder
participating in the Registered Exchange Offer shall be required to represent to
the Issuers and the Guarantors that, at the time of the consummation of the
Registered Exchange Offer:

                  (i) any New Securities received by such Holder will be
         acquired in the ordinary course of business;

                  (ii) such Holder will have no arrangement or understanding
         with any Person to participate in the distribution of the Securities or
         the New Securities within the meaning of the Act; and

                  (iii) such Holder is not an Affiliate of the Issuers or any
         Guarantor.

         (f) If any Initial Purchaser determines that it is not eligible to
participate in the Registered Exchange Offer with respect to the exchange of
Securities constituting any portion of an unsold allotment, at the request of
such Initial Purchaser, the Issuers, the Company and the Guarantors shall issue
and deliver to such Initial Purchaser or the Person purchasing New Securities
registered under a Shelf Registration Statement as contemplated by Section 3
hereof from such Initial Purchaser, in exchange for such Securities, a like
principal amount of New Securities. The Issuers, the Company and the Guarantors
shall use their reasonable best efforts to cause the CUSIP Service Bureau to
issue the same CUSIP number for such New Securities as for New Securities issued
pursuant to the Registered Exchange Offer.

         3. Shelf Registration. (a) If (i) due to any change in law or
applicable interpretations thereof by the Commission's staff, the Issuers, the
Company and the Guarantors determines upon advice of their outside counsel that
they are not permitted to effect the Registered Exchange Offer as contemplated
by Section 2 hereof; (ii) for any other reason the Registered Exchange Offer is
not consummated within 225 days of the date hereof; (iii) any Initial Purchaser
so requests with respect to Securities that are not eligible to be exchanged for
New Securities in the Registered Exchange Offer and that are held by it
following consummation of the Registered Exchange Offer; (iv) any Holder (other
than an Initial Purchaser) is not eligible to participate in the Registered
Exchange Offer; or (v) in the case of any Initial Purchaser that


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participates in the Registered Exchange Offer or acquires New Securities
pursuant to Section 2(f) hereof, such Initial Purchaser does not receive freely
tradeable New Securities in exchange for Securities constituting any portion of
an unsold allotment (it being understood that (x) the requirement that an
Initial Purchaser deliver a Prospectus containing the information required by
Item 507 or 508 of Regulation S-K under the Act in connection with sales of New
Securities acquired in exchange for such Securities shall result in such New
Securities being not "freely tradeable"; and (y) the requirement that an
Exchanging Dealer deliver a Prospectus in connection with sales of New
Securities acquired in the Registered Exchange Offer in exchange for Securities
acquired as a result of market-making activities or other trading activities
shall not result in such New Securities being not "freely tradeable"), the
Issuers, the Company and the Guarantors shall effect a Shelf Registration
Statement in accordance with subsection (b) below.

         (b) (i) The Issuers and the Guarantors shall as promptly as practicable
(but in no event more than 60 days after so required or requested pursuant to
this Section 3), file with the Commission and thereafter the Issuers, the
Company and the Guarantors shall use their reasonable best efforts to cause to
be declared effective under the Act a Shelf Registration Statement relating to
the offer and sale of the Securities or the New Securities, as applicable, by
the Holders thereof from time to time in accordance with the methods of
distribution elected by such Holders and set forth in such Shelf Registration
Statement; provided, however, that no Holder (other than an Initial Purchaser)
shall be entitled to have the Securities held by it covered by such Shelf
Registration Statement unless such Holder agrees in writing to be bound by all
of the provisions of this Agreement applicable to such Holder; and provided
further, that with respect to New Securities received by an Initial Purchaser in
exchange for Securities constituting any portion of an unsold allotment, the
Issuers and the Guarantors may, if permitted by current interpretations by the
Commission's staff, file a post-effective amendment to the Exchange Offer
Registration Statement containing the information required by Item 507 or 508 of
Regulation S-K, as applicable, in satisfaction of their obligations under this
subsection with respect thereto, and any such Exchange Offer Registration
Statement, as so amended, shall be referred to herein as, and governed by the
provisions herein applicable to, a Shelf Registration Statement.

                  (ii) The Issuers, the Company and the Guarantors shall use
         their reasonable best efforts to keep the Shelf Registration Statement
         continuously effective, supplemented and amended as required by the
         Act, in order to permit the Prospectus forming part thereof to be
         usable by Holders for a period of two years from the date the Shelf
         Registration Statement is declared effective by the Commission or such
         shorter period that will terminate when all the Securities or New
         Securities, as applicable, covered by the Shelf Registration Statement
         have been sold pursuant to the Shelf Registration Statement (in any
         such case, such period being called the "Shelf Registration Period").
         Each of the Issuers, the Company and the Guarantors shall be deemed not
         to have used its reasonable best efforts to keep the Shelf Registration
         Statement effective during the requisite period if it voluntarily takes
         any action that would result in Holders of Securities covered thereby
         not being able to offer and sell such Securities during that period,
         unless (A) such action is required by applicable law; or (B) such
         action is taken by the Issuers, the Company and the Guarantors in good
         faith and for valid business reasons (not including avoidance of the
         Issuers', the Company's and Guarantors' obligations hereunder),
         including the acquisition or divestiture of assets, so long as each


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         of the Issuers, the Company and the Guarantors promptly thereafter
         complies with the requirements of Section 4(k) hereof, if applicable.

                  (iii) The Issuers, the Company and the Guarantors shall cause
         the Shelf Registration Statement and the related Prospectus and any
         amendment or supplement thereto, as of the effective date of the Shelf
         Registration Statement or such amendment or supplement, (A) to comply
         in all material respects with the applicable requirements of the
         Securities Act and the rules and regulations of the Commission; and (B)
         not to contain any untrue statement of a material fact or omit to state
         a material fact required to be stated therein or necessary in order to
         make the statements therein, in the light of the circumstances under
         which they were made, not misleading.

         4. Additional Registration Procedures. In connection with any Shelf
Registration Statement and, to the extent applicable, any Exchange Offer
Registration Statement, the following provisions shall apply.

         (a) The Issuers, the Company and the Guarantors shall:

                  (i) furnish to you, not less than five Business Days prior to
         the filing thereof with the Commission, a copy of any Shelf
         Registration Statement, and each amendment thereof and each amendment
         or supplement, if any, to the Prospectus included therein (including
         all documents incorporated by reference therein after the initial
         filing) and shall use their best efforts to reflect in each such
         document, when so filed with the Commission, such comments as you
         reasonably propose;

                  (ii) include the information set forth in Annex A hereto on
         the facing page of the Exchange Offer Registration Statement, in Annex
         B hereto in the forepart of the Exchange Offer Registration Statement
         in a section setting forth details of the Exchange Offer, in Annex C
         hereto in the underwriting or plan of distribution section of the
         Prospectus contained in the Exchange Offer Registration Statement, and
         in Annex D hereto in the letter of transmittal delivered pursuant to
         the Registered Exchange Offer;

                  (iii) if requested by an Initial Purchaser, include the
         information required by Item 507 or 508 of Regulation S-K, as
         applicable, in the Prospectus contained in the Exchange Offer
         Registration Statement; and

                  (iv) in the case of a Shelf Registration Statement, include
         the names of the Holders that propose to sell Securities pursuant to
         the Shelf Registration Statement as selling security holders.

         (b) The Issuers, the Company and the Guarantors shall ensure that:

                  (i) any Registration Statement and any amendment thereto and
         any Prospectus forming part thereof and any amendment or supplement
         thereto complies in all material respects with the Act and the rules
         and regulations thereunder; and

                  (ii) any Registration Statement and any amendment thereto does
         not, when it becomes effective, contain an untrue statement of a
         material fact or omit to state


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         a material fact required to be stated therein or necessary to make the
         statements therein not misleading.

         (c) The Company shall advise you, the Holders of Securities covered by
any Shelf Registration Statement and any Exchanging Dealer under any Exchange
Offer Registration Statement that has been provided in writing to the Company a
telephone or facsimile number and address for notices, and, if requested by you
or any such Holder or Exchanging Dealer, shall confirm such advice in writing
(which notice pursuant to clauses (ii)-(v) hereof shall be accompanied by an
instruction to suspend the use of the Prospectus until the Issuers and the
Guarantors shall have remedied the basis for such suspension):

                  (i) when a Registration Statement and any amendment thereto
         has been filed with the Commission and when the Registration Statement
         or any post-effective amendment thereto has become effective;

                  (ii) of any request by the Commission for any amendment or
         supplement to the Registration Statement or the Prospectus or for
         additional information;

                  (iii) of the issuance by the Commission of any stop order
         suspending the effectiveness of the Registration Statement or the
         initiation of any proceedings for that purpose;

                  (iv) of the receipt by the Issuers, the Company or any
         Guarantor of any notification with respect to the suspension of the
         qualification of the securities included therein for sale in any
         jurisdiction or the initiation of any proceeding for such purpose; and

                  (v) of the happening of any event that requires any change in
         the Registration Statement or the Prospectus so that, as of such date,
         the statements therein are not misleading and do not omit to state a
         material fact required to be stated therein or necessary to make the
         statements therein (in the case of the Prospectus, in the light of the
         circumstances under which they were made) not misleading.

         (d) The Issuers, the Company and the Guarantors shall use their
reasonable best efforts to obtain the withdrawal of any order suspending the
effectiveness of any Registration Statement or the qualification of the
securities therein for sale in any jurisdiction at the earliest possible time.

         (e) The Issuers, the Company and the Guarantors shall furnish to each
Holder of Securities covered by any Shelf Registration Statement, without
charge, at least one copy of such Shelf Registration Statement and any
post-effective amendment thereto, including all material incorporated therein by
reference, and, if the Holder so requests in writing, all exhibits thereto
(including exhibits incorporated by reference therein).

         (f) The Issuers, the Company and the Guarantors shall, during the Shelf
Registration Period, deliver to each Holder of Securities covered by any Shelf
Registration Statement, without charge, as many copies of the Prospectus
(including each preliminary Prospectus) included in such Shelf Registration
Statement and any amendment or supplement


                                       9
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thereto as such Holder may reasonably request. Each of the Issuers and the
Guarantors consents to the use of the Prospectus or any amendment or supplement
thereto by each of the selling Holders of securities in connection with the
offering and sale of the securities covered by the Prospectus, or any amendment
or supplement thereto, included in the Shelf Registration Statement.

         (g) The Issuers, the Company and the Guarantors shall furnish to each
Exchanging Dealer which so requests, without charge, at least one copy of the
Exchange Offer Registration Statement and any post-effective amendment thereto,
including all material incorporated by reference therein, and, if the Exchanging
Dealer so requests in writing, all exhibits thereto (including exhibits
incorporated by reference therein).

         (h) The Issuers, the Company and the Guarantors shall promptly deliver
to each Initial Purchaser, each Exchanging Dealer and each other Person required
to deliver a Prospectus during the Exchange Offer Registration Period, without
charge, as many copies of the Prospectus included in such Exchange Offer
Registration Statement and any amendment or supplement thereto as any such
Person may reasonably request. Each of the Issuers, the Company and the
Guarantors consents to the use of the Prospectus or any amendment or supplement
thereto by any Initial Purchaser, any Exchanging Dealer and any such other
Person that may be required to deliver a Prospectus following the Registered
Exchange Offer in connection with the offering and sale of the New Securities
covered by the Prospectus, or any amendment or supplement thereto, included in
the Exchange Offer Registration Statement.

         (i) Prior to the Registered Exchange Offer or any other offering of
Securities pursuant to any Registration Statement, the Issuers, the Company and
the Guarantors shall use their reasonable best efforts to arrange, if necessary,
for the qualification of the Securities or the New Securities for sale under the
laws of such jurisdictions as any Holder shall reasonably request and will
maintain such qualification in effect so long as required to enable the offer
and sale in such jurisdictions of the Securities or New Securities; provided
that in no event shall the Issuers, the Company or the Guarantors be obligated
to qualify to do business in any jurisdiction where they are not then so
qualified or to take any action that would subject them to service of process in
suits, other than those arising out of the Initial Placement, the Registered
Exchange Offer or any offering pursuant to a Shelf Registration Statement, in
any such jurisdiction where they are not then so subject.

         (j) The Issuers, the Company and the Guarantors shall cooperate with
the Holders of Securities to facilitate the timely preparation and delivery of
certificates representing New Securities or Securities to be issued or sold
pursuant to any Registration Statement free of any restrictive legends and in
such denominations and registered in such names as Holders may request.

         (k) Upon the occurrence of any event contemplated by subsections
(c)(ii) through (v) above during the period for which the Issuers, the Company
and the Guarantors are required under this Agreement to maintain an effective
Registration Statement. The Issuers, the Company and the Guarantors shall
promptly prepare a post-effective amendment to the applicable Registration
Statement or an amendment or supplement to the related Prospectus or file any
other required document so that, as thereafter delivered to Initial Purchasers
of the


                                       10
<PAGE>


securities included therein, the Prospectus will not include an untrue statement
of a material fact or omit to state any material fact necessary to make the
statements therein, in the light of the circumstances under which they were
made, not misleading. In such circumstances, the period of effectiveness of the
Exchange Offer Registration Statement provided for in Section 2 and the Shelf
Registration Statement provided for in Section 3(b) shall each be extended by
the number of days from and including the date of the giving of a notice of
suspension pursuant to Section 4(c) to and including the date when the Initial
Purchasers, the Holders of the Securities and any known Exchanging Dealer shall
have received such amended or supplemented Prospectus pursuant to this Section.

         (l) Not later than the effective date of any Registration Statement,
the Issuers, the Company and the Guarantors shall provide a CUSIP number for the
Securities or the New Securities, as the case may be, registered under such
Registration Statement and provide the Trustee with printed certificates for
such Securities or New Securities, in a form eligible for deposit with The
Depository Trust Company.

         (m) The Issuers, the Company and the Guarantors shall comply with all
applicable rules and regulations of the Commission and shall make generally
available to their security holders as soon as practicable after the effective
date of the applicable Registration Statement an earnings statement satisfying
the provisions of Section 11(a) of the Act.

         (n) The Issuers and the Guarantors shall cause the Indenture or the New
Securities Indenture, as the case may be, to be qualified under the Trust
Indenture Act, as required by applicable law, in a timely manner.

         (o) The Issuers and the Guarantors may require each Holder of
securities to be sold pursuant to any Shelf Registration Statement to furnish to
the Issuers and the Guarantors such information regarding the Holder and the
distribution of such securities as the Issuers and the Guarantors may from time
to time reasonably require for inclusion in such Registration Statement. The
Issuers and the Guarantors may exclude from such Shelf Registration Statement
the Securities of any Holder that fails to furnish such information within a
reasonable time after receiving such request.

         (p) In the case of any Shelf Registration Statement, the Issuers, the
Company and the Guarantors shall enter into such and take all other appropriate
actions (including if requested an underwriting agreement in customary form) in
order to expedite or facilitate the registration or the disposition of the
Securities, and in connection therewith, if an underwriting agreement is entered
into, cause the same to contain indemnification provisions and procedures no
less favorable than those set forth in Section 6 (or such other provisions and
procedures acceptable to the Majority Holders and the Managing Underwriters, if
any, with respect to all parties to be indemnified pursuant to Section 6.

         (q) In the case of any Shelf Registration Statement, each of the
Issuers, the Company and the Guarantors shall:

                  (i) make reasonably available for inspection by the Holders of
         Securities to be registered thereunder, any underwriter participating
         in any disposition


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         pursuant to such Registration Statement, and any attorney, accountant
         or other agent retained by the Holders or any such underwriter all
         relevant financial and other records, pertinent corporate documents and
         properties of the Company and its subsidiaries;

                  (ii) cause the Company's and Arch Western's respective
         officers, directors and employees to supply all relevant information
         reasonably requested by the Holders or any such underwriter, attorney,
         accountant or agent in connection with any such Registration Statement
         as is customary for similar due diligence examinations; provided,
         however, that any information that is designated in writing by the
         Company or Arch Western, in good faith, as confidential at the time of
         delivery of such information shall be kept confidential by the Holders
         or any such underwriter, attorney, accountant or agent, unless such
         disclosure is made in connection with a court proceeding or required by
         law, or such information becomes available to the public generally or
         through a third party without an accompanying obligation of
         confidentiality;

                  (iii) make such representations and warranties to the Holders
         of Securities registered thereunder and the underwriters, if any, in
         form, substance and scope as are customarily made by issuers to
         underwriters in primary underwritten offerings and covering matters
         including, but not limited to, those set forth in the Purchase
         Agreement;

                  (iv) obtain opinions of counsel to the Issuers, the Company
         and the Guarantors and updates thereof (which counsel and opinions (in
         form, scope and substance) shall be reasonably satisfactory to the
         Managing Underwriters, if any) addressed to each selling Holder and the
         underwriters, if any, covering such matters as are customarily covered
         in opinions requested in underwritten offerings and such other matters
         as may be reasonably requested by such Holders and underwriters;

                  (v) obtain "cold comfort" letters and updates thereof from the
         independent certified public accountants of the Company, Arch Western,
         Canyon Fuel Company, LLC and Vulcan Coal Holdings, L.L.C. (and, if
         necessary, any other independent certified public accountants of any
         subsidiary of the Company or of any business acquired by the Company
         for which financial statements and financial data are, or are required
         to be, included in the Registration Statement), addressed to each
         selling Holder of Securities registered thereunder and the
         underwriters, if any, in customary form and covering matters of the
         type customarily covered in "cold comfort" letters in connection with
         primary underwritten offerings; and

                  (vi) deliver such documents and certificates as may be
         reasonably requested by the Majority Holders and the Managing
         Underwriters, if any, including those to evidence compliance with
         Section 4(k) and with any customary conditions contained in the
         underwriting agreement or other agreement entered into by the Issuers,
         the Company and the Guarantors.

The actions set forth in clauses (iii), (iv), (v) and (vi) of this Section shall
be performed at (A) the effectiveness of such Registration Statement and each
post-effective amendment thereto; and (B)


                                       12
<PAGE>


each closing under any underwriting or similar agreement as and to the extent
required thereunder.

         (r) In the case of any Exchange Offer Registration Statement, each of
the Issuers, the Company and the Guarantors shall, for any Initial Purchaser
which is exchanging Securities for New Securities in the Exchange Offer:

                  (i) make reasonably available for inspection by such Initial
         Purchaser, and any attorney, accountant or other agent retained by such
         Initial Purchaser, all relevant financial and other records, pertinent
         corporate documents and properties of the Company, Arch Western and
         their respective subsidiaries;

                  (ii) cause the Company's and Arch Western's respective
         officers, directors and employees to supply all relevant information
         reasonably requested by such Initial Purchaser or any such attorney,
         accountant or agent in connection with any such Registration Statement
         as is customary for similar due diligence examinations; provided,
         however, that any information that is designated in writing by the
         Company and Arch Western, in good faith, as confidential at the time of
         delivery of such information shall be kept confidential by such Initial
         Purchaser or any such attorney, accountant or agent, unless such
         disclosure is made in connection with a court proceeding or required by
         law, or such information becomes available to the public generally or
         through a third party without an accompanying obligation of
         confidentiality;

                  (iii) make such representations and warranties to such Initial
         Purchaser, in form, substance and scope as are customarily made by
         issuers to underwriters in primary underwritten offerings and covering
         matters including, but not limited to, those set forth in the Purchase
         Agreement;

                  (iv) obtain opinions of counsel to the Issuers, the Company
         and the Guarantors and updates thereof (which counsel and opinions (in
         form, scope and substance) shall be reasonably satisfactory to such
         Initial Purchaser and its counsel, addressed to such Initial Purchaser,
         covering such matters as are customarily covered in opinions requested
         in underwritten offerings and such other matters as may be reasonably
         requested by such Initial Purchaser or its counsel;

                  (v) obtain "cold comfort" letters and updates thereof from the
         independent certified public accountants of the Company, Arch Western,
         Canyon Fuel Company, LLC and Vulcan Coal Holdings, L.L.C. (and, if
         necessary, any other independent certified public accountants of any
         subsidiary of the Company or of any business acquired by the Company
         for which financial statements and financial data are, or are required
         to be, included in the Registration Statement), addressed to such
         Initial Purchaser, in customary form and covering matters of the type
         customarily covered in "cold comfort" letters in connection with
         primary underwritten offerings, or if requested by such Initial
         Purchaser or its counsel in lieu of a "cold comfort" letter, an
         agreed-upon procedures letter under Statement on Auditing Standards No.
         35, covering matters requested by such Initial Purchaser or its
         counsel; and


                                       13
<PAGE>


                  (vi) deliver such documents and certificates as may be
         reasonably requested by such Initial Purchaser or its counsel,
         including those to evidence compliance with Section 4(k) and with
         conditions customarily contained in underwriting agreements.

The foregoing actions set forth in clauses (iii), (iv), (v), and (vi) of this
Section shall be performed at the close of the Registered Exchange Offer and the
effective date of any post-effective amendment to the Exchange Offer
Registration Statement.

         (s) If a Registered Exchange Offer is to be consummated, upon delivery
of the Securities by Holders to the Issuers and the Guarantors (or to such other
Person as directed by the Issuers and the Guarantors) in exchange for the New
Securities, the Issuers and the Guarantors shall mark, or caused to be marked,
on the Securities so exchanged that such Securities are being canceled in
exchange for the New Securities. In no event shall the Securities be marked as
paid or otherwise satisfied.

         (t) The Issuers, the Company and the Guarantors shall use their best
efforts (i) if the Securities have been rated prior to the initial sale of such
Securities, to confirm such ratings will apply to the Securities or the New
Securities, as the case may be, covered by a Registration Statement; or (ii) if
the Securities were not previously rated, to cause the Securities covered by a
Registration Statement to be rated with at least one nationally recognized
statistical rating agency, if so requested by Majority Holders with respect to
the related Registration Statement or by any Managing Underwriters.

         (u) In the event that any Broker-Dealer shall underwrite any Securities
or participate as a member of an underwriting syndicate or selling group or
"assist in the distribution" (within the meaning of the Rules of Fair Practice
and the By-Laws of the National Association of Securities Dealers, Inc.)
thereof, whether as a Holder of such Securities or as an underwriter, a
placement or sales agent or a broker or dealer in respect thereof, or otherwise,
assist such Broker-Dealer in complying with the requirements of such Rules and
By-Laws, including, without limitation, by:

                  (i) if such Rules or By-Laws shall so require, engaging a
         "qualified independent underwriter" (as defined in such Rules) to
         participate in the preparation of the Registration Statement, to
         exercise usual standards of due diligence with respect thereto and, if
         any portion of the offering contemplated by such Registration Statement
         is an underwritten offering or is made through a placement or sales
         agent, to recommend the yield of such Securities;

                  (ii) indemnifying any such qualified independent underwriter
         to the extent of the indemnification of underwriters provided in
         Section 6 hereof; and

                  (iii) providing such information to such Broker-Dealer as may
         be required in order for such Broker-Dealer to comply with the
         requirements of such Rules.

                  (iv) The Issuers, the Company and the Guarantors shall use
         their best efforts to take all other steps necessary to effect the
         registration of the Securities or the New Securities, as the case may
         be, covered by a Registration Statement.


                                       14
<PAGE>


         5. Registration Expenses. The Issuers, the Company and the Guarantors
shall bear all expenses incurred in connection with the performance of their
obligations under Sections 2, 3 and 4 hereof and, in the event of any Shelf
Registration Statement, will reimburse the Holders for the reasonable fees and
disbursements of one firm or counsel designated by the Majority Holders to act
as counsel for the Holders in connection therewith, and, in the case of any
Exchange Offer Registration Statement, will reimburse the Initial Purchasers for
the reasonable fees and disbursements of counsel acting in connection therewith.

         6. Indemnification and Contribution. (a) Each of the Issuers, the
Company and the Guarantors agrees, jointly and severally, to indemnify and hold
harmless each Holder of Securities or New Securities, as the case may be,
covered by any Registration Statement (including each Initial Purchaser and,
with respect to any Prospectus delivery as contemplated in Section 4(h) hereof,
each Exchanging Dealer), the directors, officers, employees and agents of each
such Holder and each Person who controls any such Holder within the meaning of
either the Act or the Exchange Act against any and all losses, claims, damages
or liabilities, joint or several, to which they or any of them may become
subject under the Act, the Exchange Act or other Federal or state statutory law
or regulation, at common law or otherwise, insofar as such losses, claims,
damages or liabilities (or actions in respect thereof) arise out of or are based
upon any untrue statement or alleged untrue statement of a material fact
contained in the Registration Statement as originally filed or in any amendment
thereof, or in any preliminary Prospectus or the Prospectus, or in any amendment
thereof or supplement thereto, or arise out of or are based upon the omission or
alleged omission to state therein a material fact required to be stated therein
or necessary to make the statements therein not misleading, and agrees to
reimburse each such indemnified party, as incurred, for any legal or other
expenses reasonably incurred by them in connection with investigating or
defending any such loss, claim, damage, liability or action; provided, however,
that the Issuers, the Company and the Guarantors will not be liable in any case
to the extent that any such loss, claim, damage or liability arises out of or is
based upon any such untrue statement or alleged untrue statement or omission or
alleged omission made therein in reliance upon and in conformity with written
information furnished to the Issuers, the Company and the Guarantors by or on
behalf of any such Holder specifically for inclusion therein. This indemnity
agreement will be in addition to any liability which the Issuers, the Company
and the Guarantors may otherwise have.

         Each of the Issuers, the Company and the Guarantors also agrees to
indemnify or contribute as provided in Section 6(d) to Losses of each any
underwriter of Securities or New Securities, as the case may be, registered
under a Shelf Registration Statement, their directors, officers, employees or
agents and each Person who controls such underwriter on substantially the same
basis as that of the indemnification of the Initial Purchasers and the selling
Holders provided in this Section 6(a) and shall, if requested by any Holder,
enter into an underwriting agreement reflecting such agreement, as provided in
Section 4(p) hereof.

         (b) Each Holder of securities covered by a Registration Statement
(including each Initial Purchaser and, with respect to any Prospectus delivery
as contemplated in Section 4(h) hereof, each Exchanging Dealer) severally agrees
to indemnify and hold harmless each of the Issuers, the Company and the
Guarantors, each of its directors, each of its officers who signs such
Registration Statement and each Person who controls the Issuers, the Company or
any Guarantor within the meaning of either the Act or the Exchange Act, to the
same extent as the


                                       15
<PAGE>


foregoing indemnity from each of the Issuers, the Company and the Guarantors to
each such Holder, but only with reference to written information relating to
such Holder furnished to the Issuers, the Company and the Guarantors by or on
behalf of such Holder specifically for inclusion in the documents referred to in
the foregoing indemnity. This indemnity agreement will be in addition to any
liability which any such Holder may otherwise have.

         (c) Promptly after receipt by an indemnified party under this Section 6
or notice of the commencement of any action, such indemnified party will, if a
claim in respect thereof is to be made against the indemnifying party under this
Section, notify the indemnifying party in writing of the commencement thereof;
but the failure so to notify the indemnifying party (i) will not relieve it from
liability under paragraph (a) or (b) above unless and to the extent it did not
otherwise learn of such action and such failure results in the forfeiture by the
indemnifying party of substantial rights and defenses; and (ii) will not, in any
event, relieve the indemnifying party from any obligations to any indemnified
party other than the indemnification obligation provided in paragraph (a) or (b)
above. The indemnifying party shall be entitled to appoint counsel of the
indemnifying party's choice at the indemnifying party's expense to represent the
indemnified party in any action for which indemnification is sought (in which
case the indemnifying party shall not thereafter be responsible for the fees and
expenses of any separate counsel retained by the indemnified party or parties
except as set forth below); provided, however, that such counsel shall be
satisfactory to the indemnified party. Notwithstanding the indemnifying party's
election to appoint counsel to represent the indemnified party in an action, the
indemnified party shall have the right to employ separate counsel (including
local counsel), and the indemnifying party shall bear the reasonable fees, costs
and expenses of such separate counsel if (i) the use of counsel chosen by the
indemnifying party to represent the indemnified party would present such counsel
with a conflict of interest; (ii) the actual or potential defendants in, or
targets of, any such action include both the indemnified party and the
indemnifying party and the indemnified party shall have reasonably concluded
that there may be legal defenses available to it and/or other indemnified
parties which are different from or additional to those available to the
indemnifying party; (iii) the indemnifying party shall not have employed counsel
satisfactory to the indemnified party to represent the indemnified party within
a reasonable time after notice of the institution of such action; or (iv) the
indemnifying party shall authorize the indemnified party to employ separate
counsel at the expense of the indemnifying party. An indemnifying party will
not, without the prior written consent of the indemnified parties, settle or
compromise or consent to the entry of any judgment with respect to any pending
or threatened claim, action, suit or proceeding in respect of which
indemnification or contribution may be sought hereunder (whether or not the
indemnified parties are actual or potential parties to such claim or action)
unless such settlement, compromise or consent includes an unconditional release
of each indemnified party from all liability arising out of such claim, action,
suit or proceeding.

         (d) In the event that the indemnity provided in paragraph (a) or (b) of
this Section is unavailable to or insufficient to hold harmless an indemnified
party for any reason, then each applicable indemnifying party shall have a joint
and several obligation to contribute to the aggregate losses, claims, damages
and liabilities (including legal or other expenses reasonably incurred in
connection with investigating or defending same) (collectively "Losses") to
which such indemnified party may be subject in such proportion as is appropriate
to reflect the relative benefits received by such indemnifying party, on the one
hand, and such indemnified party, on the other hand, from the Initial Placement
and the Registration Statement which


                                       16
<PAGE>


resulted in such Losses; provided, however, that in no case shall any Initial
Purchaser or any subsequent Holder of any Security or New Security be
responsible, in the aggregate, for any amount in excess of the purchase discount
or commission applicable to such Security, or in the case of a New Security,
applicable to the Security that was exchangeable into such New Security, as set
forth on the cover page of the Final Memorandum, nor shall any underwriter be
responsible for any amount in excess of the underwriting discount or commission
applicable to the securities purchased by such underwriter under the
Registration Statement which resulted in such Losses. If the allocation provided
by the immediately preceding sentence is unavailable for any reason, the
indemnifying party and the indemnified party shall contribute in such proportion
as is appropriate to reflect not only such relative benefits but also the
relative fault of such indemnifying party, on the one hand, and such indemnified
party, on the other hand, in connection with the statements or omissions which
resulted in such Losses as well as any other relevant equitable considerations.
Benefits received by each of the Issuers, the Company and the Guarantors shall
be deemed to be equal to the sum of (x) the total net proceeds from the Initial
Placement (before deducting expenses) and (y) the total amount of additional
interest which the Issuers and the Guarantors were not required to pay as a
result of registering the securities covered by the Registration Statement which
resulted in such Losses. Benefits received by the Initial Purchasers shall be
deemed to be equal to the total purchase discounts and commissions from the
Initial Placement, and benefits received by any other Holders shall be deemed to
be equal to the value of receiving Securities or New Securities, as applicable,
registered under the Act. Benefits received by any underwriter shall be deemed
to be equal to the total underwriting discounts and commissions, as set forth on
the cover page of the Prospectus forming a part of the Registration Statement
which resulted in such Losses. Relative fault shall be determined by reference
to, among other things, whether any alleged untrue statement or omission relates
to information provided by the indemnifying party, on the one hand, or by the
indemnified party, on the other hand, the intent of the parties and their
relative knowledge, access to information and opportunity to correct or prevent
such untrue statement or omission. The parties agree that it would not be just
and equitable if contribution were determined by pro rata allocation (even if
the Holders were treated as one entity for such purpose) or any other method of
allocation which does not take account of the equitable considerations referred
to above. Notwithstanding the provisions of this paragraph (d), no Person guilty
of fraudulent misrepresentation (within the meaning of Section 11(f) of the Act)
shall be entitled to contribution from any Person who was not guilty of such
fraudulent misrepresentation. For purposes of this Section, each Person who
controls a Holder within the meaning of either the Act or the Exchange Act and
each director, officer, employee and agent of such Holder shall have the same
rights to contribution as such Holder, and each Person who controls the Issuers,
the Company or any Guarantor within the meaning of either the Act or the
Exchange Act, each officer of the Issuers, the Company or any Guarantor who
shall have signed the Registration Statement and each director of the Issuers,
the Company or any Guarantor shall have the same rights to contribution as the
Issuers, the Company and the Guarantors, subject in each case to the applicable
terms and conditions of this paragraph (d).

         (e) The provisions of this Section will remain in full force and
effect, regardless of any investigation made by or on behalf of any Holder or
the Issuers, the Company or any Guarantor or any of the officers, directors or
controlling Persons referred to in this Section hereof, and will survive the
sale by a Holder of securities covered by a Registration Statement.


                                       17
<PAGE>


         7. Underwritten Registrations. (a) If any of the Securities or New
Securities, as the case may be, covered by any Shelf Registration Statement are
to be sold in an underwritten offering, the Managing Underwriters shall be
selected by the Majority Holders.

         (b) No Person may participate in any underwritten offering pursuant to
any Shelf Registration Statement, unless such Person (i) agrees to sell such
Person's Securities or New Securities, as the case may be, on the basis
reasonably provided in any underwriting arrangements approved by the Persons
entitled hereunder to approve such arrangements; and (ii) completes and executes
all questionnaires, powers of attorney, indemnities, underwriting agreements and
other documents reasonably required under the terms of such underwriting
arrangements.

         8. No Inconsistent Agreements. The Issuers, the Company and the
Guarantors have not, as of the date hereof, entered into, nor shall they, on or
after the date hereof, enter into, any agreement with respect to their
securities that is inconsistent with the rights granted to the Holders herein or
otherwise conflicts with the provisions hereof.

         9. Amendments and Waivers. The provisions of this Agreement, including
the provisions of this sentence, may not be amended, qualified, modified or
supplemented, and waivers or consents to departures from the provisions hereof
may not be given, unless the Issuers, the Company and the Guarantors have
obtained the written consent of the Majority Holders (or, after the consummation
of any Registered Exchange Offer in accordance with Section 2 hereof, of New
Securities); provided that, with respect to any matter that directly or
indirectly affects the rights of any Initial Purchaser hereunder, the Issuers,
the Company and the Guarantors shall obtain the written consent of each such
Initial Purchaser against which such amendment, qualification, supplement,
waiver or consent is to be effective. Notwithstanding the foregoing (except the
foregoing proviso), a waiver or consent to departure from the provisions hereof
with respect to a matter that relates exclusively to the rights of Holders whose
Securities or New Securities, as the case may be, are being sold pursuant to a
Registration Statement and that does not directly or indirectly affect the
rights of other Holders may be given by the Majority Holders, determined on the
basis of Securities or New Securities, as the case may be, being sold rather
than registered under such Registration Statement.

         10. Notices. All notices and other communications provided for or
permitted hereunder shall be made in writing by hand-delivery, first-class mail,
telex, telecopier or air courier guaranteeing overnight delivery:

         (a) if to a Holder, at the most current address given by such holder to
the Company in accordance with the provisions of this Section, which address
initially is, with respect to each Holder, the address of such Holder maintained
by the Registrar under the Indenture, with a copy in like manner to Citigroup
Global Markets Inc;

         (b) if to you, initially at the respective addresses set forth in the
Purchase Agreement; and

         (c) if to the Issuers, the Company or any Guarantor, initially at its
address set forth in the Purchase Agreement.


                                       18
<PAGE>


         All such notices and communications shall be deemed to have been duly
given when received.

         The Initial Purchasers or the Issuers, the Company and the Guarantors
by notice to the other parties may designate additional or different addresses
for subsequent notices or communications.

         11. Successors. This Agreement shall inure to the benefit of and be
binding upon the successors and assigns of each of the parties, including,
without the need for an express assignment or any consent by the Issuers, the
Company and the Guarantors thereto, subsequent Holders of Securities and the New
Securities. Each of the Issuers, the Company and the Guarantors hereby agrees to
extend the benefits of this Agreement to any Holder of Securities and the New
Securities, and any such Holder may specifically enforce the provisions of this
Agreement as if an original party hereto.

         12. Counterparts. This agreement may be in signed counterparts, each of
which shall an original and all of which together shall constitute one and the
same agreement.

         13. Headings. The headings used herein are for convenience only and
shall not affect the construction hereof.

         14. Applicable Law. This Agreement shall be governed by and construed
in accordance with the laws of the State of New York applicable to contracts
made and to be performed in the State of New York.

         15. Severability. In the event that any one of more of the provisions
contained herein, or the application thereof in any circumstances, is held
invalid, illegal or unenforceable in any respect for any reason, the validity,
legality and enforceability of any such provision in every other respect and of
the remaining provisions hereof shall not be in any way impaired or affected
thereby, it being intended that all of the rights and privileges of the parties
shall be enforceable to the fullest extent permitted by law.

         16. Securities Held by the Company or Arch Western, etc. Whenever the
consent or approval of Holders of a specified percentage of principal amount of
Securities or New Securities is required hereunder, Securities or New
Securities, as applicable, held by the Company or Arch Western, or their
Affiliates (other than subsequent Holders of Securities or New Securities if
such subsequent Holders are deemed to be Affiliates solely by reason of their
holdings of such Securities or New Securities) shall not be counted in
determining whether such consent or approval was given by the Holders of such
required percentage.


                                       19
<PAGE>


         If the foregoing is in accordance with your understanding of our
agreement, please sign and return to us the enclosed duplicate hereof, whereupon
this letter and your acceptance shall represent a building agreement among the
Issuers, the Company and the Guarantors and the several Initial Purchasers.


                                                     Very truly yours,



<Table>
<Caption>
<S>                                       <C>
ARCH WESTERN FINANCE, LLC                 ARCH COAL, INC.


By:    /s/ JAMES E. FLORCZAK              By:    /s/ JAMES E. FLORCZAK
   -----------------------------------       -----------------------------------
Name:    James E. Florczak                Name:    James E. Florczak
Title:   Vice President and Treasurer     Title:   Treasurer


ARCH WESTERN RESOURCES, LLC               THUNDER BASIN COAL COMPANY, L.L.C.


By:    /s/ JAMES E. FLORCZAK              By:    /s/ JAMES E. FLORCZAK
   -----------------------------------       -----------------------------------
Name:    James E. Florczak                Name:    James E. Florczak
Title:   Vice President and Treasurer     Title:   Vice President and Treasurer


MOUNTAIN COAL COMPANY, L.L.C.             ARCH OF WYOMING, LLC


By:    /s/ JAMES E. FLORCZAK              By:    /s/ JAMES E. FLORCZAK
   -----------------------------------       -----------------------------------
Name:    James E. Florczak                Name:    James E. Florczak
Title:   Vice President and Treasurer     Title:   Vice President and Treasurer


TRITON COAL COMPANY, LLC                  ARCH WESTERN BITUMINOUS GROUP, LLC


By:    /s/ JAMES E. FLORCZAK              By:    /s/ JAMES E. FLORCZAK
   -----------------------------------       -----------------------------------
Name:    James E. Florczak                Name:    James E. Florczak
Title:   Vice President and Treasurer     Title:   Vice President and Treasurer
</Table>


                                       20
<PAGE>


The foregoing Agreement is hereby
confirmed and accepted as of the date
first above written.

Citigroup Global Markets Inc.
J.P. Morgan Securities Inc.
Morgan Stanley & Co. Incorporated

By: Citigroup Global Markets Inc.

By:     /s/ STRIB KOSTER
    ----------------------------
    Name: Strib Koster
    Title:     Managing Director

For themselves and the other several
Initial Purchasers named in Schedule I
of the Purchase Agreement.


                   21
<PAGE>


                                                                         ANNEX A

         Each Broker-Dealer that receives New Securities for its own account
pursuant to the Exchange Offer must acknowledge that it will deliver a
prospectus in connection with any resale of such New Securities. The Letter of
Transmittal states that by so acknowledging and by delivering a prospectus, a
Broker-Dealer will not be deemed to admit that it is an "underwriter: within the
meaning of the Securities Act. This Prospectus, as it may be amended or
supplemented from time to time, may be used by a Broker-Dealer in connection
with resales of New Securities received in exchange for Securities where such
Securities were acquired by such Broker-Dealer as a result of market-making
activities or other trading activities. The Issuers and the Guarantors have
agreed that, starting on the Expiration Date (as defined herein) and ending on
the close of business one year after the Expiration Date, they will make this
Prospectus available to any Broker-Dealer for use in connection with any such
resale. See "Plan of Distribution".


<PAGE>


                                                                         ANNEX B

         Each Broker-Dealer that receives New Securities for its own account in
exchange for Securities, where such Securities were acquired by such
Broker-Dealer as a result of market-making activities or other trading
activities, must acknowledge that it will deliver a prospectus in connection
with any resale of such New Securities. See "Plan of Distribution".


<PAGE>


                                                                         ANNEX C


                              PLAN OF DISTRIBUTION

         Each Broker-Dealer that receives New Securities for its own account
pursuant to the Exchange Offer must acknowledge that it will deliver a
prospectus in connection with any resale of such New Securities. This
Prospectus, as it may be amended or supplemented from time to time, may be used
by a Broker-Dealer in connection with resales of New Securities received in
exchange for Securities where such Securities were acquired as a result of
market-making activities or other trading activities. The Issuers and the
Guarantors have agreed that, starting on the Expiration Date and ending on the
close of business 180 days after the Expiration Date, they will make this
Prospectus, as amended or supplemented, available to any Broker-Dealer for use
in connection with any such resale. In addition, until __________, 20___,
dealers effecting transactions in the New Securities may be required to deliver
a prospectus.

         The Issuers and the Guarantors will not receive any proceeds from any
sale of New Securities by brokers-dealers. New Securities received by
Broker-Dealers for their own account pursuant to the Exchange Offer may be sold
from time to time in one or more transactions in the over-the-counter market, in
negotiated transactions, through the writing of options on the New Securities or
a combination of such methods of resale, at market prices prevailing at the time
of resale, at prices related to such prevailing market prices or negotiated
prices. Any such resale may be made directly to purchasers or to or through
brokers or dealers who may receive compensation in the form of commissions or
concessions from any such Broker-Dealer and/or the purchasers of any such New
Securities. Any Broker-Dealer that resales New Securities that were received by
it for its own account pursuant to the Exchange Offer and any broker or dealer
that participates in a distribution of such New Securities may be deemed to be
an "underwriter" within the meaning of the Securities Act and any profit of any
such resale of New Securities and any commissions or concessions received by any
such Persons may be deemed to be underwriting compensation under the Securities
Act. The Letter of Transmittal states that by acknowledging that it will deliver
and by delivering a prospectus, a Broker-Dealer will not be deemed to admit that
it is an "underwriter" within the meaning of the Securities Act.

         For a period of 180 days after the Expiration Date, the Issuers and the
Guarantors will promptly send additional copies of this Prospectus and any
amendment or supplement to this Prospectus to any Broker-Dealer that requests
such documents in the Letter of Transmittal. The Issuers and the Guarantors have
agreed to pay all expenses incident to the Exchange Offer (including the
expenses of one counsel for the holder of the Securities) other than commissions
or concessions of any brokers or dealers and will indemnify the holders of the
Securities (including any Broker-Dealers) against certain liabilities, including
liabilities under the Securities Act.


<PAGE>


                                                                         ANNEX D

Rider A

                  CHECK HERE IF YOU ARE A BROKER-DEALER AND WISH TO RECEIVE 10
                  ADDITIONAL COPIES OF THE PROSPECTUS AND 10 COPIES OF ANY
                  AMENDMENTS OR SUPPLEMENTS THERETO.

                  Name:
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                  Address:
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Rider B

If the undersigned is not a Broker-Dealer, the undersigned represents that it
acquired the New Securities in the ordinary course of its business, it is not
engaged in, and does not intend to engage in, a distribution of New Securities
and it has not arrangements or understandings with any Person to participate in
a distribution of the New Securities. If the undersigned is a Broker-Dealer that
will receive New Securities for its own account in exchange for Securities, it
represents that the Securities to be exchange for New Securities were acquired
by it as a result of market-making activities or other trading activities and
acknowledges that it will deliver a prospectus in connection with any resale of
such New Securities; however, by so acknowledging and by delivering a
prospectus, the undersigned will not be deemed to admit that it is an
"underwriter" within the meaning of the Securities Act.