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                                                                    EXHIBIT 4.28

PORTIONS OF THIS EXHIBIT HAVE BEEN OMITTED PURSUANT TO A REQUEST FOR
CONFIDENTIAL TREATMENT FILED WITH THE SECURITIES AND EXCHANGE COMMISSION. THE
OMISSIONS HAVE BEEN INDICATED BY ("***"), AND EACH PAGE CONTAINING CONFIDENTIAL
INFORMATION IS FOOTNOTED WITH THE PHRASE "FOIA CONFIDENTIAL TREATMENT." THE
OMITTED TEXT HAS BEEN FILED SEPARATELY WITH THE SECURITIES AND EXCHANGE
COMMISSION.

DATE - NOVEMBER 1, 2002

       AGREEMENT BETWEEN *** AND VIM FOR THE EXTRACTION AND SALE OF SILICA

This Agreement dated this 1st day of November, 2002, for a term of five (5)
years, by and between VICTORVILLE INDUSTRIAL MINERALS, INC., (hereafter
designated as "VIM") whose mailing address is P.O. Box 278, Oro Grande,
California, 92368 and ***.

WHEREAS, *** owns and/or controls a considerable amount of real property near
Oro Grande, California, upon which *** conducts Portland Cement manufacturing
operations and related activities (the "*** Oro Grande Property")

WHEREAS, certain portions of the *** Oro Grande Property contains certain
deposits of aggregates that *** does not intend to use in its manufacture of
Portland Cement;

WHEREAS, VIM desires to extract and purchase from *** such aggregates, and in
particular, silica material, from certain designated portions of said *** Oro
Grande Property; and

WHEREAS *** desires to permit the extraction and subsequent sale of such
aggregates and silica materials to VIM from said certain portions of the *** Oro
Grande Property;

WITNESSETH, that the parties hereto, in consideration of the mutual promises and
undertakings herein contained, mutually agree as follows:

1.)  SCOPE OF SALE AND PURCHASE OF SILICA: VIM agrees to extract and purchase
     silica from sections of the *** Oro Grande Property identified on Exhibit
     "A" which is attached hereto and incorporated herein by reference (the
     "Silica Land"). The parties acknowledge that although the *** Oro Grande
     Property encompasses more real property than is designated on Exhibit "A"
     as the Silica Land, (i) *** shall have no obligation to provide areas for
     extraction other than the those agreed to as the Silica Land at the
     execution of this Agreement and designated on Exhibit "A"; and (ii) VIM
     shall have no right or obligation to conduct a silica operation and/or the
     associated reclamation on any portion of the *** Oro Grande Property other
     than the Silica Land designated and/or defined for such activity on Exhibit
     "A" (and the designated access to the Silica Land in

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     accordance with Section 16 hereof), or pursuant to the agreement in place
     between *** and VIM dated October 1, 2001.

2.)  RECLAMATION PLAN AND PERMITTING CONSISTENCY

     The parties acknowledge that they will work cooperatively to bring
     consistency to the reclamation plans and permits, if applicable, for the
     work that VIM performs pursuant to this agreement and its agreement dated
     October 1, 2001. To further this commitment, VIM and TXI shall continue to
     meet with, and work with, the County of San Bernardino to realign the
     boundaries for the reclamation plans depicted on the Exhibit "A" map as
     follows:

     First, VIM shall have the boundaries for the VIM Reclamation Plan for the
     October 1, 2001 Agreement, hereinafter referred to as TXI-I, realigned to
     have the green (TXI#1-A) and yellow (TXT#1-B) shaded areas marked within
     TXI-I expanded to include the blue shaded area correspondently marked
     TXI#1-C. The yellow area marked TXI#1-B is currently in both the VIM and
     TXI Reclamation Plans and the blue TXI#1-C shaded area is not currently a
     part of any reclamation plan. VIM agrees to modify the TXI-I plan with the
     County of San Bernardino to include the blue shaded area TXI#1-C.

     Second, VIM shall have the boundaries for its newly anticipated reclamation
     plan for TXI-II conform to include the area shaded blue on the Exhibit "A"
     and shown as TXI#2-A. The green and yellow areas marked TXI#2-B and TM#2-C
     respectively shall remain within the purview of ***'s current reclamation
     plan (84M-009). VIM will initiate TMI#2 mining in the TXI#2 B and C areas
     and depending on the sequencing of VIM's Atlas Project, VIM may or may not
     pursue the permitting and mining of TXI#2-A.

     All haul roads, (and ingress and egress roads), of every type shall be
     preserved pursuant to the agreements the parties have reached in the past,
     and which are memorialized by their prior written agreements.

3.)  CONDUCT OF OPERATIONS ON *** ORO GRANDE PROPERTY. Notwithstanding anything
     herein to the contrary, VIM and *** each acknowledge that, at all times
     during which VIM is conducting its silica operations and/or associated
     reclamation on the Silica Land pursuant to this Agreement,

     (i)  *** shall be actively conducting its portland cement manufacturing
          operations and related activities on portions of the *** Oro Grande
          Property adjacent to and contiguous with the Silica Land; and

     (ii) The designated daily access to the Silica Land shall be through a
          portion of ***'s manufacturing operations and across roads heavily
          used by *** in its manufacturing operations on the *** Oro Grande
          Property; and

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     (iii) *** has made no representation or warranty as to any conditions on or
          pertaining to any portion of the *** Oro Grande Property, the Silica
          Land and/or access to the Silica Land, and VIM accepts same "AS IS AND
          WITH ALL FAULTS".

     This provision shall survive the termination/expiration of this Agreement
     for all purposes, including but not limited to determinations of
     indemnification pursuant to Section 15(a) hereof.

4.)  WARRANTY: VIM hereby affirmatively acknowledges that all silica extracted
     and removed from the Silica Land by VIM is extracted and removed in an "AS
     IS AND WITH ALL FAULTS" condition for all purchases (the extraction and
     removal) of silica by VIM, pursuant to this Agreement, and that all sales
     are final, and without (i) any expressed or implied warranties, of any type
     or nature, as provided for by the Uniform Commercial Code; and/or (ii) any
     expressed or implied warranties as to characteristics, specifications or
     quality (environmental or otherwise) of the silica.

5.)  QUANTITIES: ***

6.)  TERM: This Agreement, commencing on the date of execution of the Agreement,
     shall extend through November 1, 2007. *** shall not unreasonably withhold
     its consent to extend the term of this Agreement to enable VIM to complete
     contractual obligations it has entered into during the term of this
     Agreement, and may extend beyond the expiration date. Notwithstanding the
     foregoing, this Agreement may be terminated, with or without cause, by
     either party upon six (6) months advanced written notice, from one party to
     the other.

7.)  PRICING: VIM shall pay *** for all silica extracted and removed from the
     Silica Land in TXI I areas at a rate of $*** per ton. VIM shall pay ***
     for all silica extracted and removed from the TXI II areas which fall
     within the *** Reclamation Plan (TXI#2-B and TXI#2-C) at a rate of $*** per
     ton and $*** per ton for silica removed from TXI#2 areas which will fall
     under the VIM Reclamation Plan (area TX#2-A only) Refer to Exhibit "A" for
     a location of the silica lands under this agreement. *** shall invoice VIM
     on the basis of tonnage calculations provided in Section 8 below. Full
     payment shall be made to *** at ***'s Oro Grande office within thirty (30)
     days of VIM'S receipt of each monthly invoice.

8.)  TONNAGE CALCULATIONS: Payment for tonnage of silica removed from the Silica
     Land will be determined through the use of the applicable rate, provided
     above, times the number of loads removed from the Silica Land by VIM, and
     verified, as necessary, by *** as follows. Standard weight measurements
     shall be derived in the following manner: An outside neutral contractor to
     VIM and *** shall be hired to haul three loads; the loads to be loaded by
     VIM. These loads will then be driven across VIM's certified scale, as well
     as ***'s/TXI's certified scale. The net average of the three loads shall
     determine the billing rate. This procedure will be repeated every six
     months. The weight for each load

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     established by this process shall be the weight per load for all billings
     between the parties for the following six-month period of time.

     VIM shall deliver to *** each month a written statement, setting forth by
     weight the quantity of silica removed from the Silica Land. VIM shall keep
     complete records of all silica removed from the Silica Land herein. VIM
     further agrees that such records shall be subject to ***'s inspection, upon
     twenty four (24) hours notice to VIM that *** requests such an inspection,
     and upon a notice from *** to VIM indicating that such an inspection shall
     occur only during VIM's reasonable and customary business hours of
     operation. *** acknowledges and agrees that only those VIM business records
     concerning this Agreement for the extraction of silica are open for ***'s
     inspection. *** further acknowledges and agrees that any such inspection
     shall not constitute a waiver by VIM of any applicable privileges that may
     attach to such records, shall not constitute a waiver of the
     confidentiality afforded to such records, if any, and shall not constitute
     the waiver of the proprietary nature of such records, if any.

9.)  INDEPENDENT CONTRACTOR: VIM is and shall remain an independent contractor
     in the performance of the work, maintaining complete control of VIM's
     workmen and operations. Neither VIM nor anyone employed or engaged by VIM
     shall become an agent, representative, servant, or employee of *** in the
     performance of the work or any part thereof.

10.) PERMITS/COMPLIANCE WITH LAWS: VIM shall be fully responsible for obtaining
     all necessary environmental permits for its operations on the lands
     identified in this agreement. VIM is also fully responsible for the
     compliance of its operations with all applicable permits, rules,
     regulations, and/or laws.

     VIM, through execution of this agreement, agrees all work performed on the
     *** Oro Grande Property will comply with the requirements applicable to the
     approved *** Reclamation Plan (84M-009) dated February 23, 1984 on the ***
     Oro Grande Property attached hereto, and incorporated herein by this
     reference, as Exhibit "B" (hereinafter the "Exhibit "B" and/or "VIM'S
     Obligation under the TXI Reclamation Plan") for purposes of the work to be
     performed in areas which fall within the *** Reclamation Plan. VIM will
     comply with applicable requirements of the VIM Reclamation Plan (97M-O1) in
     areas which fall within this reclamation plan as defined in Exhibit "A".
     *** will make available all necessary documentation to inform VIM of said
     conditions of the *** Reclamation Plan (84M-009).

11.) CLEANUP: Unless otherwise agreed in writing by the parties at the time of
     termination/expiration of this Agreement, within six (6) months after the
     expiration/termination of this Agreement, VIM shall remove all equipment
     and unused non-native materials provided for its work, and agrees to place
     the Silica Land as described and/or depicted within Exhibit "A".
     Furthermore, *** shall provide a location on its property for the placement
     of mining waste materials according to the Exhibit "A".

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12.) DRUG-FREE WORK PLACE: VIM represents it maintains a drug free workplace
     policy. As a result of this existing policy, VIM agrees to advise its
     employees and the employees of its subcontractors and agents (hereinafter
     for the purposes of this provision collectively referred to as "VIM
     employees"), that: (i) it is the policy of *** that the use, possession,
     sale, transfer, or purchase of illegal drugs on the *** Oro Grande
     Property, is prohibited; (ii) entry onto the *** Oro Grande Property
     constitutes the presence of an employee's vehicle on the *** Oro Grande
     Property and/or any personal effects of an employee which the employee
     brings with him or her while entering, on or leaving the *** Oro Grande
     Property; and (iii) any employee who is found in violation of the policy or
     who refuses to permit an inspection by an authorized representative of ***
     may be removed and barred from the *** Oro Grande Property, at the
     discretion of ***.

13.) SAFETY: While on the *** Oro Grande Property, VIM shall observe, and shall
     cause its subcontractors and agents to observe, such safety rules as ***
     shall prescribe as necessary for the protection of ***'s personnel and
     property. ***'s Safety Book is attached hereto and is incorporated herein
     as Exhibit "C." VIM acknowledges its receipt of this Safety Book. VIM
     further affirms its own commitment to comply with its own safety procedures
     and policies, as applicable to the work it shall be performing pursuant to
     this Agreement. In addition, both parties affirm their commitment to comply
     with all applicable MSHA and CAL/OSHA regulations applicable to each during
     the term of this Agreement.

14.) INSURANCE: VIM acknowledges that it has and shall maintain, at its own
     expense, for the duration of this Agreement (and shall require all of its
     subcontractors to obtain, carry and maintain for the duration of this
     Agreement), the following insurance coverage with following minimum limits:

     (a)  Workers Compensation as required by laws and regulations applicable to
          and covering employees of VIM (or the subcontractor) engaged in the
          performance of the work under this Agreement with the applicable
          statutory limits, as well as employer's liability insurance with
          minimum limits of $1,000,000.

     (b)  A General Liability Insurance Policy covering its operations for legal
          liability it causes with minimum limits of $5,000,000.

     (c)  Automobile Liability of all owned and non-owned/hired vehicles with
          minimum limits of $1,000,000.

     All insurance coverage shall be obtained from one or more insurance
     companies which have an A.M. Best rating of A- or better (or an equivalent
     rating on an equivalent rating system).

     All insurance policies shall contain a waiver of subrogation; and each
     certificate shall name *** as an additional insured.

     VIM agrees to notify *** in writing, at least thirty (30) days in advance
     of any significant modification, expiration or cancellation of any such
     insurance policies covering VIM'S

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     actions and obligations under this Agreement, including but not limited to
     modifications, expiration or cancellation of insurance coverage meeting the
     minimum requirements set forth in this Section 14.

     VIM acknowledges that on or before the execution of this Agreement, VIM
     presented *** with a copy of a Certificate of Currency dated April 17, 2001
     evidencing VIM'S then-current insurance coverage. Upon execution of this
     Agreement, VIM shall furnish to *** the equivalent of a certificate of
     insurance describing that the above insurances are in full force and
     effect.

     Notwithstanding anything herein to the contrary, VIM acknowledges that any
     insurance coverage held by VIM shall not relieve or limit VIM's obligations
     and/or liability pursuant to this Agreement, including but not limited to
     the indemnification set forth in Section 15 hereof.

15.) INDEMNIFICATION AND DISPUTE RESOLUTION:

     (a)  Indemnification: ***.

     (b)  Dispute Resolution: Any dispute between the Parties arising out of or
          relating to this Agreement (including, without limitation, its
          creation, interpretation, enforcement or breach) or any document or
          instrument referred to herein (a "Dispute") shall be resolved as
          follows:

          Settlement Negotiations: The Parties in good faith shall attempt to
          settle any Disputes within thirty (30) days of receipt by one party
          from the other of a notice to this effect. If such negotiations fail
          to resolve the Dispute, the Parties shall proceed as set forth below.

          Arbitration: Any Dispute which is not resolved through the settlement
          negotiations provided for above shall be resolved by binding
          arbitration before a qualified, experienced, unbiased, and neutral
          arbitrator selected by the Parties. The arbitration shall be conducted
          in the State of California and governed by the rules set forth in
          California's Code of Civil Procedure sections 1281 et seq., (or
          similarly enacted statutory guidelines for the handling of private
          contractually-based arbitration proceedings). The Arbitrator shall
          abide by California law in rendering his decision and shall determine
          which Party is entitled to recover under this Agreement, and shall
          provide for any other appropriate legal or equitable relief.

          Jurisdiction, Venue and Choice of Law: Solely for purposes of this
          Agreement, the Parties consent to jurisdiction in San Bernardino
          County, California. Any disputes between the parties hereunder shall
          be resolved, by and under the laws of the State of California without
          regard to its choice of law provisions.

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16.) ACCESS: *** shall provide VIM access to the current extraction site through
     the *** Oro Grande Property by means of a designated route or area. VIM
     agrees that *** may reasonably limited its access to the area denoted on
     Exhibit "A" and Exhibit "B" when necessary to 's ongoing operations, and/or
     any modifications to its facilities or planned construction currently
     anticipated to take place during the term of this agreement, , but may not
     do so for more than any two day period of time. VIM further agrees it shall
     provide *** with timely written notice of any changes VIM requests for a
     different or modified access route, and that it shall not proceed to use a
     different or modified access route without ***'s prior acknowledgement and
     consent to the same, which consent by *** shall not be unreasonably
     withheld. VIM shall provide *** with two days notice of any such proposed
     change.

17.) FUGITIVE DUST CONTROL: VIM understands *** is required to mitigate fugitive
     dust associated with any operations on the *** Oro Grande property. VIM
     agrees to control fugitive dust emissions associated with its extraction,
     processing, management and transportation of silica materials while on the
     *** Oro Grande property, and , in particular, within the Silica Land.

18.) NOTICE: All notices given under this Agreement shall (unless otherwise
     expressly provided herein) be in writing and signed by the party giving
     such notice. it shall be deemed given when personally delivered, or five
     (5) business days thereafter when deposited in the U.S. Mail, with proper
     postage prepaid and addressed to the other party at its respective
     following address, or at such other address as either party may hereafter
     furnish by a notice given pursuant thereto:

               If to ***:           ***
                            Attn:   ***

               If to VIM:           Victorville Industrial Minerals, Inc.
                                    P.O. Box 278
                                    Oro Grande, CA. 92368
                            Attn:   Jacqueline Campo, Mine Supervisor

19.)     NO ASSIGNMENT: This Agreement, nor any obligation or right thereunder,
         may not be assigned by VIM without ***'s express written consent, which
         consent by *** shall not be unreasonably withheld.

20.)     NO PARTNERSHIP, JOINT VENTURE OR PRINCIPAL-AGENT RELATIONSHIP: Nothing
         contained in this Agreement, nor any acts of the parties, shall be
         deemed by the parties to create the relationship of principal and
         agent, or of employer and employee, or of partnership, or of joint
         venture, or of any other association between the parties, and no
         provisions in this Agreement are intended to create or constitute any
         person a third party beneficiary hereof.

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21.) ENTIRE AGREEMENT: This Agreement constitutes the entire agreement between
     the parties on the subject matter contained herein and supersedes any prior
     written or oral agreements or statements.

22.) MODIFICATIONS AND WAIVERS: All modifications to this Agreement must be in
     writing and signed by the parties hereto. No provision of this Agreement
     can be waived, except in writing, signed by the party waiving such
     provision, nor shall failure to object to any breach of a provision of this
     Agreement waive the right to object to a subsequent breach of the same or
     any other provision.

23.) SEVERABILITY: If any provision of this Agreement shall, for any reason, be
     held violative of any applicable law, and so much of said Agreement is held
     to be unenforceable, then the invalidity of such a specific provision
     herein shall not be held to invalidate any other provisions herein, and all
     other provisions herein shall remain in full force and effect. Furthermore,
     in lieu of such illegal, invalid, or unenforceable provision, there shall
     be added automatically as a part of this Agreement a provision as similar
     in terms to such illegal, invalid or unenforceable provision as may be
     possible and be legal, valid and enforceable.

24.) GOVERNING LAW AND COMPLIANCE WITH THE LAW: This Agreement shall be
     interpreted under and enforced in accordance with, and subject to, the laws
     of the State of California. Further, the parties agree that they shall
     comply with all federal, state and municipal statutes, ordinances and
     regulations that may apply to their respective operations, duties and
     responsibilities under the terms of this Agreement, and for the duration of
     this Agreement.

25.) NO CONSTRUCTION AGAINST THE AUTHOR: Each party warrants and represents that
     it has participated fully in the negotiation, preparation and drafting of
     this Agreement, and that the language used in this Agreement is a product
     of that participation. The rule that an ambiguity in language is to be
     construed against the author accordingly shall have no effect as to this
     Agreement.

26.) HEADINGS: The captions to the several paragraphs hereof are not a part of
     this Agreement and shall have no legal significance, but are merely guides
     or labels to assist in locating and reading the paragraphs contained
     herein.

27.) FURTHER ASSURANCES: Each party agrees to do any thing and sign any
     documents, which are necessary and desirable to accomplish any of the
     goals, terms or conditions of this Agreement.

28.) COUNTERPARTS: This Agreement may be executed in two or more counterparts,
     each of which shall be deemed an original, but of which together shall
     constitute one and the same instrument

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29.)

     IN WITNESS WHEREOF, *** and VIM have executed this Agreement on the day and
year first written above.

                                        ***


                                        By. ***
                                            ------------------------------------
                                        Name: ***
                                        Title: ***


                                        VICTORVILLE INDUSTRIAL MATERIALS INC.


                                        By: /s/ Charles Harrson 11/19/02
                                            ------------------------------------
                                        Name: Charles Harrson
                                        Title: Plant Manager, JHBP Fontana
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EXHIBIT "A" SILICA LANDS

***

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Additional Notes:

The proposed TM #2 Waste Dump, Haul Road and possible use of the Comet Pit for
waste disposal to be included in ***'s reclamation plan. If this is not possible
per County of San Bernardino, then VIM to haul waste to TMI#1 Waste Dump.

VIM to initiate mining in the TXI#2-B and C areas for TXI#2 under TXI
Reclamation Plan. Depending on the sequencing of VIM's Atlas Project, VIM may or
may not permit and mine TXI#2-A.

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