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                                                                   EXHIBIT 10.43

            NINTH AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT

         THIS NINTH AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT (this
"Amendment") is dated as of October 28, 1999 among: HS RESOURCES, INC., a
corporation formed under the laws of the State of Delaware (the "Borrower");
each of the lenders that is a signatory hereto; and THE CHASE MANHATTAN BANK (in
its individual capacity, "Chase"), as agent for the Lenders (in such capacity,
together with its successors in such capacity, the "Agent").

                                 R E C I T A L S
                                 ---------------

         A. The Borrower, the Agent, and the Lenders (as defined in the Credit
Agreement as hereafter defined) have entered into that certain Amended and
Restated Credit Agreement dated as of June 14, 1996, as amended by the First
Amendment to Amended and Restated Credit Agreement dated as of June 17, 1996,
the Second Amendment to Amended and Restated Credit Agreement dated as of
November 27, 1996, the Third Amendment to Amended and Restated Credit Agreement
dated as of December 15, 1997, the Fourth Amendment to Amended and Restated
Credit Agreement dated as of June 16, 1998, the Fifth Amendment to Amended and
Restated Credit Agreement dated as of September 1, 1998, the Sixth Amendment to
Amended and Restated Credit Agreement dated as of December 10, 1998, the Seventh
Amendment to Amended and Restated Credit Agreement dated as of December 31, 1998
and the Eighth Amendment to Amended and Restated Credit Agreement dated as of
August 27, 1999 (as amended, the "Credit Agreement"), pursuant to which the
Lenders have agreed to make certain loans and extensions of credit to the
Borrower upon the terms and conditions as provided therein;

         B. The Borrower has entered into negotiations with KN Energy, Inc. (now
Kinder-Morgan, Inc.("KMI")) to acquire KMI's Wattenberg gathering and
transmission assets and in connection therewith, KMI and KN Gas Gathering, Inc.,
("KNGG"), as Sellers, and the Borrower, as Buyer, will execute that certain
Purchase and Sale Agreement and KNGG and the Borrower will execute that certain
Operating Services Agreement, both to be dated on or about October 29, 1999,
together such agreements providing substantially the following:

                  (i) Sellers would sell and Buyer would purchase the Sellers'
         Wattenberg gathering and transmissions system located in Adams,
         Arapahoe, Boulder, Denver, Larimer and Weld Counties, Colorado,
         including without limitation, rights in a lease as lessee covering some
         or all of such Property ("Wattenberg Gathering System");

                  (ii) The Borrower would commence operation of the Wattenberg
         Gathering System on November 1, 1999. The Borrower would be obligated
         to pay the costs of operating the Wattenberg Gathering System and would
         bear the risk of uninsured loss. KNGG would pay the Borrower a fixed
         fee that is expected to equal the costs of operating the Wattenberg
         Gathering System;

                  (iii) Sellers would retain legal title or lease rights to the
         Wattenberg Gathering System until the Closing, to be held on or about
         December 15, 2001;

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                  (iv) The Borrower would pay $1,000,000 in cash on or about
         October 29, 1999;

                  (v) The Borrower would extend its commitment of gas to the
         Wattenberg Gathering System through December 31, 2001, under the terms
         of existing gathering agreements;

                  (vi) The Borrower would pay a facility fee of $360,000 per
         month from January 2000 through December 2001;

                  (vii) Sellers would retain Wattenberg Gathering System gross
         margin revenue through December 31, 2001, provided that the Borrower
         would pay Sellers any shortfall below 95% of currently projected gross
         margin revenue of approximately $2,300,000 per month and the Borrower
         would receive any excess above 105% of that amount; and

                  (viii) The Borrower would make a final payment at Closing of
         $30,000,000, consisting of a cash payment of approximately $7,000,000
         and an assumption of an operating lease concerning gathering equipment
         with a projected balance as of closing of approximately $23,000,000.

         C. The Borrower, the Agent, and the Lenders now desire to make certain
amendments to the Credit Agreement to permit such acquisition.

         NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration and the mutual benefits, covenants and agreements herein
expressed, the parties hereto now agree as follows:

         1. All capitalized terms used in this Amendment and not otherwise
defined herein shall have the meanings ascribed to such terms in the Credit
Agreement.

         2. Section 1.02 of the Credit Agreement is hereby supplemented, where
alphabetically appropriate, with the addition of the following definitions:

                  "Ninth Amendment" shall mean that certain Ninth Amendment to
         Amended and Restated Credit Agreement dated as of October 28, 1999,
         among the Borrower, the Lenders and the Agent.

                  "Wattenberg Gathering System" shall have the meaning assigned
         in the Recitals to the Ninth Amendment.

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         3. Section 9.01 of the Credit Agreement is hereby amended by adding the
following clause (p):

                  "(p) the consideration to be paid, performed and assumed by
         the Borrower or HS Gathering, LLC for the acquisition of the Wattenberg
         Gathering System as described in the Recitals to the Ninth Amendment,
         and a guaranty by the Borrower of the obligations of the current lessee
         under the operating lease as well as the obligations of HS Gathering,
         LLC as a result of the assumption of such lease."

         4. Section 9.02 of the Credit Agreement is hereby amended by adding the
following clause (h):

                  "(h) a Lien on certain Properties of the Wattenberg Gathering
         System owned by HS Gathering, LLC to secure Debt assumed or incurred to
         acquire the Wattenberg Gathering System and all extension, renewals and
         replacements of such Debt."

         5. Section 9.03(m) of the Credit Agreement is hereby amended by adding
the following before the semi-colon at the end of the clause:

         "and an investment by the Borrower and its Subsidiaries in the
         Wattenberg Gathering System through the Borrower's 100% ownership of HS
         Gathering, LLC and KN Wattenberg Transmission, LLC"

         6. Section 9.18 of the Credit Agreement is hereby amended by adding the
following before the period at the end of the first sentence in such section:

         ", other than HS Gathering, LLC and KN Wattenberg Transmission, LLC,
         which will be 100% owned by the Borrower"

         7. This Amendment shall become binding on the Lenders when, and only
when, the following conditions shall have been satisfied and the Agent shall
have received each of the following, as applicable, in form and substance
satisfactory to the Agent or its counsel:

                  (a) counterparts of this Amendment executed by the Borrower
         and the Majority Lenders;

                  (b) a Guaranty Agreement executed by HS Gathering, LLC; and

                  (c) the execution, delivery and effectiveness of the Purchase
         and Sale Agreement covering the sale of the Wattenberg Gathering System
         to the Borrower and HS Gathering, LLC.

         8. The parties hereto hereby acknowledge and agree that, except as
specifically supplemented and amended, changed or modified hereby, the Credit
Agreement shall remain in full force and effect in accordance with its terms.

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         9. The Borrower hereby reaffirms that as of the date of this Amendment,
the representations and warranties contained in Article VII of the Credit
Agreement are true and correct on the date hereof as though made on and as of
the date of this Amendment, except as such representations and warranties are
expressly limited to an earlier date.

         10. THIS AMENDMENT (INCLUDING, BUT NOT LIMITED TO, THE VALIDITY AND
ENFORCEABILITY HEREOF) SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH,
THE LAWS OF THE STATE OF NEW YORK.

         11. This Amendment may be executed in two or more counterparts, and it
shall not be necessary that the signatures of all parties hereto be contained on
any one counterpart hereof; each counterpart shall be deemed an original, but
all of which together shall constitute one and the same instrument. Delivery of
an executed signature page of this Amendment by facsimile transmission shall be
effective as delivery of a manually executed counterpart hereof.

                          [SIGNATURES BEGIN NEXT PAGE]

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         IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
executed as of the date set forth in the opening paragraph of this Amendment..

BORROWER:                                   HS RESOURCES, INC.

                                            By:
                                               ---------------------------------
                                            Name:
                                            Title:

LENDER AND AGENT:                           THE CHASE MANHATTAN BANK

                                            By:
                                               ---------------------------------
                                            Name:
                                            Title:

LENDERS:                                    ABN AMRO BANK N.V.
                                            San Francisco International Branch

                                            By:
                                               ---------------------------------
                                            Name:
                                            Title:

                                            By:
                                               ---------------------------------
                                            Name:
                                            Title:

                                            CREDIT LYONNAIS NEW YORK BRANCH

                                            By:
                                               ---------------------------------
                                            Name:
                                            Title:

                                      S-1
<PAGE>   6

                                            UNION BANK OF CALIFORNIA, N.A.

                                            By:
                                               ---------------------------------
                                            Name:
                                            Title:

                                            WELLS FARGO BANK, N.A.

                                            By:
                                               ---------------------------------
                                            Name:
                                            Title:

                                            PARIBAS

                                            By:
                                               ---------------------------------
                                            Name:
                                            Title:

                                            By:
                                               ---------------------------------
                                            Name:
                                            Title:

                                            BANK ONE, NA (FORMERLY KNOWN AS
                                            FIRST NATIONAL BANK OF CHICAGO)

                                            By:
                                               ---------------------------------
                                            Name:
                                            Title:

                                            GENERAL ELECTRIC CAPITAL
                                            CORPORATION

                                            By:
                                               ---------------------------------
                                            Name:
                                            Title:

                                      S-2
<PAGE>   7

                                            MEESPIERSON CAPITAL CORP.

                                            By:
                                               ---------------------------------
                                            Name:
                                            Title:

                                            By:
                                               ---------------------------------
                                            Name:
                                            Title:

                                            ROYAL BANK OF CANADA

                                            By:
                                               ---------------------------------
                                            Name:
                                            Title:

                                            BANK OF SCOTLAND

                                            By:
                                               ---------------------------------
                                            Name:
                                            Title:

                                            FIRST UNION NATIONAL BANK

                                            By:
                                               ---------------------------------
                                            Name:
                                            Title:

                                      S-3<PAGE>   1

                                                                     EXHIBIT 4.1

<TABLE>
<S>                               <C>                                                                       <C>

         [NUMBER]                                [ZIXIT(TM) CORPORATION LOGO]                                  [SHARES]

        C
                                                     ZIXIT CORPORATION

        COMMON STOCK                   INCORPORATED UNDER THE LAWS OF THE STATE OF TEXAS                    CUSIP 98974P 10 0

                               THIS CERTIFICATE IS TRANSFERABLE IN CHICAGO, IL AND NEW YORK, NY          SEE REVERSE FOR CERTAIN
                                                                                                               DEFINITIONS

               THIS CERTIFIES THAT

               is the owner of

                   FULLY PAID AND NON-ASSESSABLE SHARES OF THE PAR VALUE OF $.01 EACH OF THE COMMON STOCK OF
                                                        ZIXIT CORPORATION

(hereinafter referred to as the "Corporation") transferable on the books of the Corporation by the holder hereof in person or by
duly authorized attorney upon surrender of this certificate properly endorsed.
         This certificate is not valid unless countersigned by the Transfer Agent and registered by the Registrar.
         WITNESS the facsimile seal of the Corporation and the facsimile signatures of its duly authorized officers.

Dated:                                                      [SEAL]

/s/ RONALD A. WOESSNER                                                       /s/ DAVID P. COOK

                  Secretary                                                      Chairman and Chief Executive Officer

COUNTERSIGNED AND REGISTERED:
         HARRIS TRUST AND SAVINGS BANK

BY                                                                                                                  TRANSFER AGENT
                                                                                                                     AND REGISTRAR

                                                                                                              AUTHORIZED SIGNATURE
</TABLE>

<PAGE>   2

                               ZixIt Corporation

        Preemptive rights are denied by the Articles of Incorporation of the
Corporation on file in the Office of the Secretary of State of Texas, and the
Corporation will furnish a copy of such Articles of Incorporation to the record
holder of this certificate without charge on written request to the Corporation
at its principal place of business or registered address. The Corporation will
also furnish any stockholder upon request without charge a statement of the
powers, designations, preferences and rights, and qualifications, limitations
and restrictions of such preferences and rights, of all classes and series of
the capital stock of the Corporation.

        The following abbreviations, when used in the inscription on the face
of this certificate, shall be construed as though they were written out in full
according to applicable laws or regulations:

<TABLE>
        <S>                                             <C>
        TEN COM -- as tenants in common                 UNIF GIFT MIN ACT -- _____________ Custodian ___________
        TEN ENT -- as tenants by the entireties                                 (Cust)                  (Minor)
        JT TEN  -- as joint tenants with right of                            under Uniform Gifts to Minors Act
                   survivorship and not as tenants                           ___________________________________
                   in common                                                               (State)
</TABLE>

   Additional abbreviations may also be used though not in the above list.

   For value received, __________________ hereby sell, assign and transfer unto

PLEASE INSERT SOCIAL SECURITY OR OTHER
   IDENTIFYING NUMBER OF ASSIGNEE
[                                    ]

________________________________________________________________________________

________________________________________________________________________________
PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS INCLUDING POSTAL ZIP CODE OF ASSIGNEE

________________________________________________________________________________

________________________________________________________________________________

_________________________________________________________________________ Shares
of the capital stock represented by the within certificate, and do hereby
irrevocably constitute and appoint _____________________________________________
Attorney to transfer the said stock on the books of the within-named
Corporation with full power of substitution in the premises.

Dated _______________________________________

                                     X__________________________________________
                                                     (SIGNATURE)

             NOTICE:

THE SIGNATURE(S) TO THIS ASSIGNMENT
MUST CORRESPOND WITH THE NAME(S) AS WRITTEN  ->
UPON THE FACE OF THE CERTIFICATE IN
EVERY PARTICULAR, WITHOUT ALTERATION OR
ENLARGEMENT, OR ANY CHANGE WHATEVER.

                                     X__________________________________________
                                                     (SIGNATURE)

                                     -------------------------------------------
                                     THE SIGNATURE(S) SHOULD BE GUARANTEED BY
                                     AN ELIGIBLE GUARANTOR INSTITUTION
                                     (BANKS, STOCKBROKERS, SAVINGS AND LOAN
                                     ASSOCIATIONS AND CREDIT UNIONS WITH
                                     MEMBERSHIP IN AN APPROVED SIGNATURE
                                     GUARANTEE MEDALLION PROGRAM), PURSUANT
                                     TO S.E.C. RULE 17Ad-15.

                                     -------------------------------------------
                                     SIGNATURE(S) GUARANTEED BY:

                                     -------------------------------------------

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