EXHIBIT 10.9.1


      [*] Indicates that the confidential portion has been omitted from this
         filed exhibit and filed separately with the Securities and Exchange
         Commission

                AMENDMENT ONE TO UNDERGROUND COAL SALES AGREEMENT


         This AMENDMENT ONE TO UNDERGROUND COAL SALES AGREEMENT ("Amendment
One"), by and between SAN JUAN COAL COMPANY, a Delaware corporation (referred to
herein as "SJCC") and PUBLIC SERVICE COMPANY OF NEW MEXICO, a New Mexico
corporation, and TUCSON ELECTRIC POWER COMPANY, an Arizona corporation
(collectively referred to herein as the "Utilities") (with SJCC and Utilities
herein sometimes collectively referred to as "Parties"), effective as of
December 15, 2003, amends that certain Underground Coal Sales Agreement dated
August 31, 2001 (the "UGCSA") between SJCC and the Utilities.

                                    RECITALS

         A. AU Mines, Inc. ("AU") has withdrawn as a partner of Cimarron Coal
Company ("Cimarron") in exchange for an undivided 31% interest in the assets of
Cimarron, and Cimarron has been reorganized into a partnership in which AU has
no further interest.

         B. SJCC has agreed to enter into with Cimarron the Installment Sale
Agreement and Release, pursuant to which SJCC will purchase all of the remaining
rights and interest of Cimarron in the La Plata leases and the La Plata mine
created or reserved under the Cimarron Assignment Agreement dated October 30,
1979, originally between Cimarron and Western Coal Company and assigned to SJCC,
as amended and modified over time by various agreements.

         C. SJCC has agreed to enter into the AU Letter Agreement dated as of
December 15, 2003 with AU amending the Cimarron Assignment Agreement dated
October 30, 1979, as amended and modified.

         NOW THEREFORE, in consideration of the terms, covenants and agreements
contained in this Amendment One and for other good and valuable consideration,
the Utilities jointly and severally agree with SJCC as follows:

                                    AGREEMENT

         1. The UGCSA is amended by deleting the text of Section 1.2 in its
entirety and replacing it with "[intentionally omitted]". The remaining sections
following 1.2 shall not be renumbered.

         2. The UGCSA is amended by adding the following definitions to Section
1.15:

                  SS) "Cimarron Coal Assignment" defined in Section 2.1.E.


<PAGE>

                  TT) "Installment Sale Agreement" defined in Section 2.1.E

                  UU) "Utility Payment Stream" defined in Section 8.5.C.

         3. The UGCSA is amended by adding a new Section 2.1.E as follows:

                  E) To perform all of the obligations contained in (i) the
                  Cimarron Coal Assignment dated October 30, 1979, originally
                  between Cimarron Coal Company and Western Coal Company and
                  assigned to SJCC, as amended and modified, including but not
                  limited to the letter amendment dated as of December 15, 2003
                  between AU Mines, Inc. and SJCC ("Cimarron Coal Assignment")
                  and (ii) the Installment Sale Agreement and Release between
                  Cimarron Coal Company and SJCC, dated as of December 15, 2003
                  ("Installment Sale Agreement").

         4. The UGCSA is amended by adding after the title line of Section 8.5,
"Other Costs", the new line:

                  Other Costs shall be the following:

         5. The UGCSA is amended by replacing the existing text of Section 8.5.C
in its entirety with the following:

                  C)       Payment of the Utility Payment Stream

                  For purposes of this Section 8.5.C, the following definitions
                  apply:

                  "Y1" is the final Implicit Price Deflator Index of the Gross
                  Domestic Product ("IPD-GDP") (defined below) for the fourth
                  quarter of 2002, presently equal to 111.25

                  "Y2" is the final IPD-GDP for the fourth quarter of 1979,
                  presently equal to 53.90.

                  "Xl" is the most recently published quarterly IPD-GDP as of
                  the Calculation Date. The Calculation Date is the 5th day of
                  the month following the month for which each Utility Payment
                  Stream payment is being made (e.g., February 5 for the January
                  payment).

                  The factors X1/Y1 and X1/Y2 as applied below in this Section
                  8.5.C are utilized to recognize the effects of inflation and
                  deflation on certain relevant base amounts.

                  The IPD-GDP as utilized in this Section 8.5.C refers to the
                  Implicit Price Deflator of the Gross Domestic Product Index
                  ("Index") published quarterly by the Bureau of Economic
                  Analysis of the U.S. Department of Commerce ("BEA").
                  Calculations for this Section 8.5.C shall be made based upon
                  the most recent Index published on the BEA website (if the BEA

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<PAGE>

                  website no longer publishes the Index, then the Index as most
                  recently published in the Survey of Current Business shall be
                  utilized), at the applicable Calculation Date. Presently,
                  information concerning the Index is disseminated by the BEA by
                  means of the Survey of Current Business, (a magazine published
                  monthly by the U.S. Department of Commerce, Economic and
                  Statistics Administration, Bureau of Economic Analysis, and
                  printed by the Government Printing Office) in a Selected NIPA
                  Table designated as "Quantity and Price Indexes for Gross
                  Domestic Product" and, also, via BEA's website on the
                  Internet, as line 4 of Table 7.1 at:
                  www.bea.doc.gov/bea/dn/nipaweb/SelectTable.asp?Selected=N#S7.

         At present, the Index is calculated and based on the reference year of
         1996 = 100. The Selected NIPA Tables are presented through quarterly
         estimates, updated monthly; the Parties agree that any update to the
         Index after the Calculation Date, caused by BEA adjusting its
         estimates, shall not result in a recalculation of the amount of a
         Utility Payment Stream payment.

         If, in the future, the BEA should change the reference year utilized to
         calculate the IPD-GDP then: Y1 shall be the IPD-GDP shown for the
         fourth quarter of 2002; and Y2 shall be the JPD-GDP shown for the
         fourth quarter of 1979, in conversion tables prepared by the BEA in
         respect to the new reference year and Xl for each succeeding Utility
         Payment Stream payment becoming due after the date of the change of
         reference years shall be determined by reference to the most recently
         published IPD-GDP, as of the Calculation Date, based on the new
         reference year.

         If the IPD-GDP should cease to be published by the BEA but another
         comparable index is published by another governmental agency then such
         index shall be utilized in the same manner as provided in this Section
         8.5.C in order to establish the amounts of the Utility Payment Stream
         becoming due for required future Utility Payment Stream payments. If no
         such index is published by governmental agencies, then such other index
         which may be available shall be utilized in a manner which will fairly
         and reasonably reflect the effects of inflation or deflation on the
         dollar amounts of the Utility Payment Stream payments.

         The Utilities shall pay to SJCC the Utility Payment Stream calculated
in two parts as follows ("Utility Payment Stream"):

                  1)       i)       [*] ("Initial Payment") paid on January 22,
                           2004 to the account described in Section 8.7.C; and

                           ii) one hundred sixty nine (169) monthly payments
                           ("Payment(s)") each in the amount calculated in this
                           Section 8.5.C(l) below, with the first Payment for
                           the month of December 2003 due on January 22, 2004,
                           and the final Payment for the month of December 2017
                           due on January 22, 2018. The terms Initial Payment
                           and Payment(s) as defined in this Section 8.5.C(1)
                           apply only in this Section 8.5.C(1).

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<PAGE>

                           The amount of each Payment shall be calculated
                           utilizing [*] as the base amount to be subject to
                           inflation and deflation adjustment and calculated
                           mathematically by the following formula applied
                           separately for each Payment:

                                    [*] x (X1/Y1) = amount of Payment

                           Utilities shall make the Payments specified in this
                           Section 8.5.C(1) to an SJCC bank account designated
                           as [*] (or such other account as either of the
                           Parties may designate upon 30 days written notice to
                           the other party) and due on the 22nd of the month
                           following the month for which the Payment is being
                           made. Payments due on a Saturday will be payable on
                           the previous Friday. Payments due on a Sunday will be
                           payable on the following Monday. Payments due on a
                           bank holiday will be payable on the next bank
                           workday.

                  2)       i)       [*] ("Initial Payment") paid on January 22,
                           2004 to the account described in Section 8.7.C; and

                           ii) one hundred sixty nine (169) monthly payments
                           ("Payment(s)") each in the amount calculated in this
                           Section 8.5.C(2) below, with the first Payment for
                           the month of December 2003 due on January 22, 2004,
                           and the final Payment for the month of December 2017
                           due on January 22, 2018. The terms Initial Payment
                           and Payment(s) as defined in this Section 8.5.C(2)
                           apply only in this Section 8.5.C(2). The amount of
                           each Payment shall be calculated by adding certain
                           payment amounts as follows:

                           Tier 1 shall be calculated utilizing [*] as the base
                           amount to be subject to inflation and deflation
                           adjustment and calculated mathematically by the
                           following formula applied separately for each
                           Payment:

                                     [*] x (X1/Y2) = Tier 1 payment

                           If the LPM Annual Production (the total tons mined
                           and delivered to the Utilities in a calendar year
                           from the La Plata Mine) is zero, no payments are due
                           for Tier 2 and Tier 3. Only if the LPM Annual
                           Production exceeds [*] tons in any year after 2003,
                           payments from at least Tier 2, and possibly Tier 3,
                           shall he added to the December Tier 1 payment, as
                           described below. Tier 2 and Tier 3 payments are only
                           calculated and applied to the December payment of
                           each year and shall be calculated utilizing [*] as
                           the base amount to be subject to inflation and
                           deflation adjustment.

                           Tier 2 only applies when LPM Annual Production
                           exceeds [*] tons in any year after 2003. If LPM
                           Annual Production exceeds [*] tons, the Tier 2
                           payment amount calculation is initiated by
                           multiplying [*] by the lesser of: i) the LPM Annual

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<PAGE>

                           Production minus [*] tons or ii) [*] tons, and then
                           multiplying the product by [*], multiplied further by
                           X1/Y2. This product multiplied by [*] is the Tier 2
                           payment amount, and it shall be added to the Tier 1
                           payment amount for December each year that Tier 2
                           applies.

                           Tier 3 only applies when LPM Annual Production
                           exceeds [*] tons in any year after 2003. If LPM
                           Annual Production exceeds [*] tons, the Tier 3
                           payment amount calculation is initiated by
                           multiplying [*] by: (the LPM Annual Production minus
                           [*] tons), and then multiplying the product by [*],
                           multiplied further by XI/Y2. This product multiplied
                           by [*] is the Tier 3 payment amount, and it shall be
                           added to the sum of the Tier 1 and Tier 2 payment
                           amounts for December each year that Tier 3 applies.

                           Utilities shall make the Payments specified in this
                           Section 8.5.C(2) to the SJCC bank account designated
                           as [*] (or such other account as either of the
                           Parties may designate upon 30 days written notice to
                           the other party) and due on the 22nd of the month
                           following the month for which the Payment is being
                           made. Payments due on a Saturday will be payable on
                           the previous Friday. Payments due on a Sunday will be
                           payable on the following Monday. Payments due on a
                           bank holiday will be payable on the next bank
                           workday.

                  By the tenth (10th) day of each month, SJCC shall provide to
                  the Utilities a detailed calculation of the Utility Payment
                  Stream due for the previous month. In the event of a dispute
                  between the Parties or with a third party over calculation of
                  payments set out in Section 8.5.C(1) or Section 8.5.C(2), the
                  Utilities shall submit their written position statement
                  regarding the disputed calculation to SJCC. A determination of
                  the same issue in a dispute resolution process involving a
                  third party, in which the Utilities' position statement is
                  presented in good faith by SJCC, shall be binding upon SJCC
                  and the Utilities for purposes of this Agreement.

         6.       The UGCSA is amended by adding the following new Section
         8.5.F:

                  F) Dispute Costs

                  In addition to the Utility Payment Stream set forth in
                  Sections 8.5.C(l) and 8.5.C(2) above, the Utilities shall pay
                  to SJCC legal fees and costs arising from disputes, if any,
                  under the Cimarron Coal Assignment and/or the Installment Sale
                  Agreement.

         7.       Section 6.1 of the UGCSA is amended by adding the following
         paragraph at the end of the current Section 6.1:

                  "SJCC shall not mine and sell coal to any third party from the
                  coal leases described in the Cimarron Coal Assignment."

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<PAGE>

         8.       Section 8.1 of the UGCSA is amended by replacing, in the first
         paragraph, the term "reimburse" with the phrase "reimburse or pay, as
         applicable,".

         9.       The UGCSA is amended by deleting the text of Section
         8.7.A(2).iii in its entirety and replacing it with "[intentionally
         omitted]". The remaining sections following Section 8.7.A(2).iii shall
         not be renumbered.

         10.      The UGCSA is amended by replacing the existing text of Section
         8.7.A(2).v in its entirety with the following: Other Miscellaneous
         Costs

         11.      The UGCSA is amended by adding the following new Section
         8.7.A(2).vi:

                  vi.      Dispute Costs

         12.      Section 8.7.C of the UGCSA is amended by replacing the
         existing text in its entirety with the following:

                  Invoices submitted by SJCC in accordance with Section 8.7
                  "Invoicing and Settlement" and any supplemental or true-up
                  invoices shall be due and payable by Utilities on the
                  twenty-second (22nd) day of the month succeeding the month for
                  which such invoice is submitted, or on the twelfth (12th) day
                  after receipt of the invoice by Utilities, whichever date is
                  later; provided, however, that payment of the Utility Payment
                  Stream by the Utilities is due the twenty-second (22nd) day of
                  the month, regardless of whether, or when, a detailed
                  calculation thereof as specified in Section 8.5.C is received
                  by the Utilities. Payment pursuant to this Agreement, except
                  for payments under Sections 8.5.C.(1) (ii) and 8.5.C.(2)(ii),
                  shall be made to SJCC by electronic funds transfer to such
                  bank accounts as SJCC may from time to time designate.

         13.      The UGCSA is amended by deleting the text of Section
         12.5.D.(1) in its entirety and replacing it with "[intentionally
         omitted]". The remaining sections following Section 12.5.D.(1) shall
         not be renumbered.

         14.      The UGCSA is amended by replacing Section 14.10.A in its
         entirety with the following:

                  A) This Agreement may not be assigned or subcontracted by SJCC
                  without the consent of Utilities, except that no consent shall
                  be required in event of an assignment of amounts receivable
                  hereunder to a bank or lending institution, or a collateral
                  assignment for purposes of securing indebtedness, or a
                  transfer under or pursuant to a mortgage, deed of trust or
                  indenture (including, without limitation, a transfer by
                  foreclosure or a sale under the power of sale contained in any
                  such mortgage, deed of trust or indenture), or a transfer to a
                  successor in interest, by merger, consolidation, sale and
                  transfer, or otherwise, acquiring all or substantially all of

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<PAGE>

                  the assets and business of SJCC, and except for transfer to a
                  subsidiary as herein below provided; provided, however, that
                  any assignee, successor in interest or transferee hereunder
                  shall first guarantee performance of this Agreement in a
                  manner satisfactory to Utilities. Notwithstanding anything to
                  the contrary contained in this Agreement, a collateral
                  assignment of the Utility Payment Stream (including, without
                  limitation, a transfer by foreclosure or a sale under a power
                  of sale contained in any such collateral assignment) shall not
                  require the assignee or transferee to guarantee performance of
                  this Agreement, and any claims or rights of setoff against the
                  Utility Payment Stream shall be subordinate to any such
                  collateral assignment (including, without limitation, a
                  transfer by foreclosure or a sale under a power of sale
                  contained in any such collateral assignment).

         15.      The UGCSA is amended by replacing the second sentence of
         Section 14.18 with the following:

                  In addition, those provisions and Exhibits referenced in, or
                  necessary to implement, the provisions that describe the
                  Parties' post-termination or post-expiration rights and
                  obligations also shall survive, including, but not limited to,
                  Sections 2.1.E, 8.5.C, 8.5.E, 8.5.F and 14.10.

         16.      The UGCSA is amended by replacing Section 1.5 with the
         following:

                  1.5      Guarantee
                  "Guarantee" shall mean the Guarantee, of even date herewith,
                  as modified from time to time by the consent of Guarantor,
                  made by BHP Minerals International Inc. and guaranteeing to
                  Utilities SJCC's performance of its obligations hereunder.

         17.      Section 14.13 of the UGCSA is amended by replacing the
         existing text in its entirety with the following:

                  This Agreement may be amended only by written instrument
                  executed by all of the Parties. Any such amendments may be
                  executed in any number of counterparts, and it shall not be
                  necessary that the signatures of all Parties be contained on
                  any counterpart. Each counterpart shall be deemed an original,
                  but all counterparts together shall constitute one and the
                  same instrument.

         18.      All other provisions of the UGCSA not specifically amended by
         this Amendment One remain in full force and effect.

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<PAGE>

         IN WITNESS  WHEREOF,  the  Parties  hereto  have caused this  Agreement
to be executed on their behalf by their respective officers, thereunto duly
authorized. Public Service Company of New Mexico



By:      /s/ Edward Padilla Jr.
      --------------------------------------
Name:  Edward Padilla Jr.
      --------------------------------------
Title: Senior Vice President                        Date:    December 15, 2003
      --------------------------------------              ----------------------


Tucson Electric Power Company

By:      /s/ Michael J. Deloncini
    ----------------------------------------
Name:  Michael J. Deloncini
      --------------------------------------
Title: Senior Vice President                        Date:    December 15, 2003
      --------------------------------------              ----------------------


San Juan Coal Company

By:      /s/ John W. Grubb
    ----------------------------------------
Name:  John W. Grubb
      --------------------------------------
Title:  President                                   Date:    December 15, 2003
      --------------------------------------              ----------------------


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<PAGE>


                              CONSENT OF GUARANTOR
         BHP Minerals International Inc., a Delaware corporation (formerly
BHP-Utah International Inc.), the guarantor of the obligations of San Juan Coal
Company under the Underground Coal Sales Agreement pursuant to the Guarantee
dated September 25, 2001 (the "Guarantee"), hereby consents to the foregoing
Amendment One to the Underground Coal Sales Agreement and agrees that all
references in the Guarantee to the Underground Coal Sales Agreement shall be
deemed to be references to the Underground Coal Sales Agreement as amended by
this Amendment One.



BHP MINERALS INTERNATIONAL INC.


By:      /s/ Earl K. Moore
    ----------------------------------------
Name:  Earl K. Moore
      --------------------------------------
Title:  President                                     Date:    12/9/03
      --------------------------------------                --------------------


By:      /s/ M. Ruth Rhodes
    ----------------------------------------
Name:  M. Ruth Rhodes
      --------------------------------------
Title:  Secretary                                     Date:    12/9/03
      --------------------------------------                --------------------


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