Exhibit 10.28

[EXECUTION]

NINTH AMENDMENT TO LOAN AGREEMENT

THIS NINTH AMENDMENT TO LOAN AGREEMENT (herein called this "Amendment") is made as of the 25th day of April, 2002, 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.

W I T N E S S E T H:

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, Agent, and Lenders desire to amend the Original Agreement for the purposes described herein;

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 Ninth Amendment to Loan Agreement.

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

ARTICLE II.
Amendment

§ 2.1. The definition of "Tranche A Maturity Date" in Section 1.1 of the Loan Agreement is hereby amended in its entirety to read as follows:

"Tranche A Maturity Date'means April 24, 2003."

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, (i) Agent shall have received for the pro rata distribution to each Lender in accordance with each Lender's Percentage Share of the Tranche A Commitment, an amendment fee in the
amount of $100,000.00 in immediately available funds, and (ii) Agent shall have also received all of the following:



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:



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 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 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 hereto 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.

[THE REMAINDER OF THIS PAGE INTENTIONALLY LEFT BLANK.]



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

| |  | WESTERN GAS RESOURCES, INC.                 
| |  | --------------------------------------------
| |  | By:                                         
| |  | BANK OF AMERICA, N.A., as Agent and Lender  
| |  | By:                                         
| |  | ABN AMRO BANK N.V., a Lender                
| |  | By:                                         
| |  | By:                                         
| |  | BANK ONE, NA (MAIN OFFICECHICAGO), a Lender
| |  | By:                                         
| |  | CREDIT LYONNAIS NEW YORK BRANCH, a Lender   
| |  | By:                                         
| |  | FLEET NATIONAL BANK, a Lender               
| |  | By:                                         

| |  | SOCIÉTÉ GÉNÉRALE SOUTHWEST AGENCY, a Lender
| |  | -------------------------------------------
| |  | By:                                        
| |  | UNION BANK OF CALIFORNIA, N.A., a Lender   
| |  | By:                                        
| |  | By:                                        
| |  | U.S. BANK NATIONAL ASSOCIATION, a Lender   
| |  | By:                                        



CONSENT AND AGREEMENT

Each of the undersigned hereby (i) consents to the provisions of this Amendment and the transactions contemplated herein, and (ii) ratifies and
confirms its respective Guaranty dated as of April 29, 1999 made by it in favor of Agent for the benefit of each Lender, and agrees that its obligations and covenants thereunder are unimpaired hereby
and shall remain in full force and effect.

Date:
April 25, 2002

| |  | MIGC, INC.
WESTERN GAS RESOURCES TEXAS, INC.
MOUNTAIN GAS RESOURCES, INC.
LANCE OIL & GAS COMPANY, INC.
WESTERN GAS WYOMING, L.L.C.
| |  | -----------------------------------------------------------------------------------------------------------------------------------
| |  | By:                                                                                                                                

CONSENT AND AGREEMENT

The undersigned hereby (i) consents to the provisions of this Amendment and the transactions contemplated herein, and (ii) ratifies and confirms its
Guaranty dated as of October 14, 1999 made by it in favor of Agent for the benefit of each Lender, and agrees that its obligations and covenants thereunder are unimpaired hereby and shall
remain in full force and effect.

Date:
April 25, 2002

| |  | MGTC, INC.
| |  | ----------
| |  | By:       



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