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SEVENTH AMENDMENT TO LOAN AGREEMENT

        THIS SEVENTH AMENDMENT TO LOAN AGREEMENT (herein called this
"Amendment") is made as of the 27th day of September, 2001 by and among Western
Gas Resources, Inc. ("Borrower"), and Bank of America, N.A. ("Agent"), and the
Lenders under the Loan Agreement referred to below.

WITNESSETH:

        WHEREAS, Borrower, Agent, and Lenders have entered into that certain
Loan Agreement dated as of April 29, 1999 (as amended, restated, or supplemented
to the date hereof, the "Original Agreement"), for the purposes and
consideration therein expressed, pursuant to which Lenders made and became
obligated to make loans to Borrower as therein provided; and

        WHEREAS, Borrower has informed Agent that Mountain Gas Resources, Inc.
is investing in a limited liability company named Rendezvous Gas Services~ LLC.,
with Questar Gas Management Company, and Borrower, Agent and Lenders desire to
amend Schedule 4 to the Original Agreement to allow such Subsidiary's investment
in such limited liability company,

        NOW, THEREFORE, in consideration of the premises and the mutual
covenants and agreements contained herein and in the Original Agreement, in
consideration of the loans which may hereafter be made by Lenders to Borrower,
and for other good and valuable consideration, the receipt and sufficiency of
which are hereby acknowledged, the parties hereto do hereby agree as follows:

ARTICLE I.
Definitions and References

§ 1.1. Defined Terms. Unless the context otherwise requires or unless otherwise
expressly defined herein, the terms defined in the Original Agreement shall have
the same meanings whenever used in this Amendment. As used herein, the following
terms shall have the following meanings:

"Amendment" means this Seventh Amendment to Loan Agreement.

"Loan Agreement" means the Original Agreement as amended by this Amendment.

ARTICLE II.
Amendment and Consent

§ 2.1. Schedule 4. Schedule 4 to the Original Loan Agreement is hereby amended
in its entirety to read as set forth on Schedule 4 attached hereto.

ARTICLE III.
Conditions of Effectiveness

§ 3.1 Effective Date. This Amendment shall become effective as of the date first
above written when, and only when, Agent shall have received all of the
following:

(a)This Amendment, duly authorized, executed and delivered by Borrower, Agent,
and each Lender, and in form and substance satisfactory to Agent.

(b)A certificate of a duly authorized officer of Borrower dated the date of this
Amendment certifying: (i) that all of the representations and warranties set
forth in Article IV hereto are true and correct at and as of the time of such
effectiveness; and (ii) as to such other corporate matters as Agent shall deem
necessary.

(c)Payment of fees and disbursements of Thompson & Knight L.L.P. relating to
this Amendment and the Loan Agreement as provided in the Loan Agreement.

(d)Agent shall have additionally received such other documents as Agent may
reasonably request.

ARTICLE IV.
Representations and Warranties

§ 4.1. Representations and Warranties of Borrower. In order to induce each
Lender to enter into this Amendment, Borrower represents and warrants on the
date hereof and as of the Effective Date to each Lender that:

(a)The representations and warranties contained in Article V of the Original
Agreement are true and correct at and as of the time of the effectiveness hereof
(except as such representations and warranties have been modified by the
transactions contemplated herein).

(b)Borrower is duly authorized to execute and deliver this Amendment and
Borrower is and will continue to be duly authorized to borrow monies and to
perform its obligations under the Loan Agreement. Borrower has duly taken all
corporate action necessary to authorize the execution and delivery of this
Amendment.

(c)The execution and delivery by Borrower of this Amendment, the performance of
its obligations hereunder and the consummation of the transactions contemplated
hereby do not and will not conflict with any provision of law, statute, rule or
regulation or of the certificate of incorporation and bylaws of Borrower or of
any material agreement, judgment, license, order or permit applicable to or
binding upon Borrower or result in the creation of any lien, charge or
encumbrance upon any assets or properties of Borrower. Except for those which
have been obtained, no consent, approval, authorization or order of any court or
governmental authority or third party is required in connection with the
execution and delivery by Borrower of this Amendment.

(d)When duly executed and delivered, this Amendment, the Loan Agreement, and
each other Loan Document, as affected hereby, will be a legal and binding
obligation of each Related Person that is a party hereto and thereto enforceable
against such Related Person in accordance with its terms, except as limited by
bankruptcy, insolvency or similar laws of general application relating to the
enforcement of creditors' rights and by equitable principles of general
application.

(e)The audited Consolidated financial statements of Borrower dated as of
December 31, 2000, and the unaudited Consolidated financial statements of
Borrower dated as of June 30, 2001, fairly present the Consolidated financial
position at such date of Borrower and the Consolidated statement of operations
and the changes in Consolidated financial position for the periods ending on
such date for Borrower. Copies of such financial statements have heretofore been
delivered to Agent. Since December 31, 2000, no material adverse change has
occurred in the financial condition or business or in the Consolidated financial
condition or business of Borrower.

ARTICLE V.
Miscellaneous

§ 5.1. Ratification of Agreements. The Original Agreement as hereby amended is
hereby ratified and confirmed in all respects. Any reference to the Loan
Agreement in any Loan Document shall be deemed to be a reference to the Original
Agreement as hereby amended. The Loan Documents, as they may be amended or
affected by this Amendment, are hereby ratified and confirmed in all respects.
The execution, delivery and effectiveness of this Amendment shall not, except as
expressly provided herein, operate as a waiver of any right, power or remedy of
Lenders under the Loan Agreement, the Notes, or any other Loan Document nor
constitute a waiver of any provision of the Loan Agreement, the Notes, or any
other Loan Document.

§ 5.2. Survival of Agreements. All representations, warranties, covenants and
agreements of Borrower herein shall survive the execution and delivery of this
of this Amendment and the performance hereof, including without limitation the
making or granting of the Loans, and shall further survive until all of the
Obligations are paid in full. All statements and agreements contained in any
certificate or instrument delivered by Borrower hereunder or under the Loan
Agreement to any Lender shall be deemed to constitute representations and
warranties by, and/or agreements and covenants of, Borrower under this Amendment
and under the Loan Agreement.

§ 5.3. Loan Documents. This Amendment is a Loan Document, and all provisions in
the Loan Agreement pertaining to Loan Documents apply hereto.

§ 5.4. Governing Law. This Amendment shall be governed by and construed in
accordance with the laws of the State of Texas and any applicable laws of the
United States of America in all respects, including construction, validity and
performance.

§ 5.5. Counterparts. This Amendment may be separately executed in counterparts
and by the different parties in separate counterparts, each of which when so
executed shall be deemed to constitute one and the same Amendment.

        THIS AMENDMENT AND THE OTHER LOAN DOCUMENTS REPRESENT THE FINAL
AGREEMENT BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR,
CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES. THERE ARE NO
UNWRITTEN ORAL AGREEMENTS OF THE PARTIES.

        IN WITNESS WHEREOF, this Amendment is executed as of the date first
above written.

    WESTERN GAS RESOURCES, INC.
 
 
By: /s/ William J. Krysiak
Name: William J. Krysiak
Title: Vice President-Finance

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SEVENTH AMENDMENT TO LOAN AGREEMENT