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                                                                   EXHIBIT 10(t)

                 MERCANTILE SHARES PURCHASE AND SALE AGREEMENT


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MERCANTILE SHARES PURCHASE AND SALE AGREEMENT (THE "AGREEMENT") EXECUTED IN THE
CITY OF MEXICO FEDERAL DISTRICT ON JUNE 9, 2005 TOGETHER WITH THE WITNESSES WHO
AFFIX THEIR SIGNATURES AT THE FOOT, BY AND BETWEEN

(I)   NICHOLAS N. CARTER, ON HIS OWN RIGHT AND THE LEGAL ENTITY, TEXAS OIL &
      CHEMICAL CO. II, INC., REPRESENTED HEREIN BY NICHOLAS N. CARTER,
      HEREINAFTER JOINTLY "SELLERS", AND

(II)  ERNESTO JAVIER GONZALEZ CASTRO AND MAURICIO RAMON AREVALO MERCADO,
      HEREINAFTER JOINTLY "BUYERS",

PURSUANT TO THE FOLLOWING REPRESENTATIONS AND CLAUSES:

                                 REPRESENTATIONS

I. BY SELLERS:

(a) Texas Oil & Chemical Co. II, Inc., through its representative:

(i) That it is a corporation organized in accordance with the laws of the United
States of America, with the legal capacity legitimation and authorizations
necessary to execute this AGREEMENT and bind itself to the terms hereof;

                                     [STAMP]

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(b) Nicholas N. Carter:

(i) That he enjoys full capacity to execute and deliver this Agreement.

(c) Both, jointly:

(i) That they are the legitimate owners in possession and full domain of
59,987,764 (FIFTY NINE MILLION NINE HUNDRED EIGHTY-SEVEN THOUSAND SEVEN HUNDRED
SIXTY-FOUR) ordinary, registered shares with a face value of P$1.00 (One Peso
00/100 Mexican Currency) each, fully subscribed and paid (the "SHARES")
representing issued, subscribed and paid capital stock of the business
corporation named PRODUCTOS QUIMICOS COIN, S.A. DE C.V. ("ISSUER)), represented
and distributed as follows:

<TABLE>
<CAPTION>
                                                    SHARES OF
                                SHARES OF FIXED  VARIABLE CAPITAL       TOTAL
       SHAREHOLDER               CAPITAL STOCK        STOCK        (VALUE IN PESOS)
-----------------------------   ---------------  ----------------  ----------------
<S>                             <C>              <C>               <C>
Texas Oil & Chemical Co. II,             99,999        59,987,764     60,087,763.00
Inc. represented by Nicholas
N. Carter

Nicholas N. Carter                            1                                1.00

            Total                       100,000        59,987,764     60,087,764.00
</TABLE>

Per this date the SHARES represent 100% (one hundred percent) of the subscribed
and paid capital stock of the ISSUER.

(ii) Per this date they have in their possession the certificates of the SHARES,
which they declare under oath are

                                     [STAMP]

                                        2

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not subject to lien, attachment, or any act or legal fact that in any manner
limits their authority for being disposed of.

(iii) ISSUER is legally organized in accordance with the laws of the United
Mexican States and its main purpose is the acquisition, lease or through any
title enjoyment of the use and possession of movable and real estate properties.

(iv) In virtue of the above representations and of the manifestations set forth
in Clause Third of the AGREEMENT, they wish to sell the SHARES to BUYERS in the
proportions further itemized, in the understanding that they represent 100% (one
hundred percent) of the issued and paid capital stock of ISSUER.

(v) For purposes of the transaction set forth in this instrument, each of them
individually and with respect to the shares held by the other, waive in favor of
the BUYERS the preemptive right granted to them under the Bylaws in effect of
ISSUER.

II BUYERS REPRESENT:

(a) That they are Mexican individuals, of age, with full

                                     [STAMP]

                                        3

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capacity to execute and deliver this Agreement.

(b) They wish to acquire the SHARES from SELLERS - in the proportions further
established -, subject to the conditions and terms of the AGREEMENT.

(c) Per this date they have inspected to their satisfaction all the legal,
accounting, tax and financial documents of ISSUER provided by SELLERS, and
consequently wish to acquire the SHARES.

Based on the above Representations, the parties execute the Agreement contained
in the following:

                                    CLAUSES:

FIRST: PURPOSE OF THE AGREEMENT. By virtue of the AGREEMENT, SELLERS sell,
assign and transfer the SHARES to BUYERS, and the latter buy and acquire the
SHARES for themselves, free of any burden, lien or affectation, in the following
proportions:

                                     [STAMP]

                                        4

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<TABLE>
<CAPTION>
                              SHARES OF FIXED  SHARES OF VARIABLE        TOTAL
         SHAREHOLDER           CAPITAL STOCK     CAPITAL STOCK     (VALUE IN PESOS)
----------------------------  ---------------  ------------------  ----------------
<S>                           <C>              <C>                 <C>
Texas Oil & Chemical Co. II,           99,998          59,987,764   60,087, 762 .00
Inc. represented by Nicholas
N. Carter

Nicholas N. Carter                          2                                  2.00

       Total                         100, 000          59,987,764     60,087,764.00
</TABLE>

SECOND: PRICE OF THE SHARES AND PAYMENT FORM: The price agreed for transfer of
the SHARES is the total amount of P$200.00 (Two Hundred Pesos Mexican Currency),
payable upon signing the AGREEMENT against delivery by SELLERS to BUYERS of the
shares certificates covering ownership of the SHARES, duly endorsed.

THIRD: REPRESENTATIONS; SELLERS jointly declare and warrant to BUYERS that the
AGREEMENT constitutes valid and enforceable obligations for SELLERS. Neither
subscription of the AGREEMENT nor fulfillment by SELLERS of any of the
provisions set forth in it: (i) shall breach, cause conflict or result in
nonperformance, early termination or rescission of any agreement, commitment or
obligation, or any other agreement where the ISSUER is party of or whereby
ISSUER or its properties or assets are bound, (ii) breach, cause conflict or
result in nonperformance of any agreement, commitment, obligation of an
agreement where SELLERS are a party of or whereby their properties or assets are
bound, and

                                     [STAMP]

                                        5

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such breach or nonperformance might produce a right for any third party over the
SHARES, (iii) breach any law or regulatory provision to which ISSUER is bound,
or breach, cause conflict or result in nonperformance by ISSUER; (iv) breach any
provision of the documents of incorporation of ISSUER, nor (v) result in
creating any lien (or any obligation to create any lien) over the properties or
assets of ISSUER.

Additionally, SELLERS represent and warrant to BUYERS the following:

1. Tax Matters: For purposes of the AGREEMENT, "Tax or Taxes" shall mean any tax
on income, on gross income, profits, franchises, licenses, transfers, sales,
use, ad valorem, customs, payrolls, withholding, employment, occupation, assets
(movable or real estate properties), on use or added value, assets tax and other
taxes, government charges, fees, contributions, withholdings, including but not
limited to fees to the Mexican Social Security, the Retirement Savings System
and Infonavit (Workers National Housing Fund), (including interest, sanctions or
additions to those Headings).

(a) ISSUER has provided BUYERS copies of the most recent

                                     [STAMP]

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general balance sheets, statements of profit and loss, net worth and cash flow
of ISSUER (altogether the "Financial Statements") and corresponding tax
statements for those periods (altogether the "Tax Statements"). Expect for the
indications provided in them, those financial Statements are complete and
correct, and were prepared according to accounting principles generally accepted
in Mexico and consistently applied during such periods, and they adequately
reflect the financial condition of ISSUER per those dates:

(b) All Tax Statements have been duly or spontaneously filed;

(c) All Taxes reflected in the Tax Statements have been duly and promptly paid
during the last five years;

(d) The Tax Statements authentically and fully reflect facts concerning income,
assets, operations and the condition of any entity that must appear in them;

(e) There are no charges, accumulations and reserves for Taxes owed or
applicable but still not due concerning income, assets and operations of ISSUER,
as there is no obligation to pay for such taxes;

(f) There is no action, lawsuit, proceeding, audit or claim

                                     [STAMP]

                                        7

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underway, or to the best knowledge of SELLERS, there is no investigation
underway concerning income taxes, assets or operations of ISSUER;

(g) There are no agreements to extend the term to encumber Taxes on income,
assets or operations of ISSUER;

(h) All taxes of ISSUER have been paid or settled, and there, has not arisen any
situation derived from audits which, by applying similar principles, might
presume the possibility of a tax claim.

2. Intellectual Property: ISSUER holds no copyrights, patents, trademarks,
licenses or sublicenses of any of the above.

3. Accounts Receivable. Accounts receivable, reimbursable deposits, expenses
paid in advance, deferred charges, loans or advance payments granted by ISSUER
to any person are disclosed in Attachment "1".

4. Consents. No consents, approvals or authorizations by, nor statements,
entries or registrations with government or regulatory authorities for
execution, delivery and fulfillment of the AGREEMENT, or development of
operations

[STAMP]

                                       8

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contemplated therein are required, nor is consent by any person necessary to
carry out the operations contemplated herein, including but not limited to,
consent by third parties with whom credits, agreements, leases or other
contracts have been executed.

5. Observance of the Laws. ISSUER has all permits necessary to develop its
business as it currently does, all of which are now fully valid and in effect,
and ISSUER complies with the respective terms and conditions established in
them. ISSUER has complied with all applicable laws, bylaws, rules, regulations,
sentences, orders, briefs, "amparos" (private rights protection enforcement
remedy) and decrees, either of states or local, by government authorities or by
judicial or administrative authorities with competence over ISSUER, its
properties or assets.

6.Payment of Dividend. Since the moment when ISSUER was incorporated and until
the date of the AGREEMENT, there has not been any kind of payment of dividend in
favor of the shareholders of ISSUER.

7. Representations. The representations by SELLERS in this AGREEMENT, and
representations set forth in the documents mentioned (including but not limited
to financial statements,

[STAMP]

                                        9

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certifications or other briefs provided or that shall be provided by SELLERS or
ISSUER to BUYERS or to any of their representatives according to the provisions
hereof or in relation to the operations contemplated herein), do not contain nor
shall contain false representations, nor fail, nor shall fail to manifest facts
that are important and necessary according to the circumstances whereby they are
issued, and therefore, the representations set forth herein or in those are not
deceitful, and continue to be true per the date of this instrument.

FOURTH: RELEASE FROM LIABILITIES. SELLERS release BUYERS and ISSUER from any
claim, complaint, procedure, liability, obligation, damage or action filed after
signing the AGREEMENT, and originated from it due to facts, events or omissions
by SELLERS or ADMINISTRATORS, originated from the incorporation of ISSUER per
the date of the AGREEMENT, regardless of the amount.

For purposes of this Clause, BUYERS must notify SELLERS with respect to any such
claim, complaint, procedure, liability, obligation, damage or action referred to
in the preceding paragraph, within 30 (thirty) business days after BUYERS are
informed of any of such liabilities, except in case the term granted to ISSUER
as a consequence of any of such liabilities

                                     [STAMP]

                                       10

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is less than 30 (thirty) business days, in which case the notice to SELLERS
according to this paragraph shall be issued at least 24 (twenty-four) hours
before expiration of such term; in the understanding that failure to issue
notice according to this Clause shall release SELLERS of any liability in this
respect, including its obligations to indemnify according to this Agreement.

The provisions of the preceding paragraph shall not be applicable to any notice
issued directly to SELLERS.

FIFTH: INDEMNIFICATION BY SELLERS. Without prejudice of the provisions set for
in Clause Fourth above, in proportion to the SHARES which they hold according to
the representations of the AGREEMENT, SELLERS bind themselves to indemnify,
defend and hold ISSUER and BUYERS harmless of any claim, action, procedure,
liability, expense, attorney fees, including but not limited to, interest,
penalties and reasonable attorney fees (jointly, the "Damages") in which ISSUER
or BUYERS might incur derived for any of the following reasons:

(a) Any imprecision or falseness in the representations by BUYERS according to
the AGREEMENT and accounting matters registered in the accounting records of the
company;

                                     [STAMP]

                                       11

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(b) Noncompliance by SELLERS of any agreement, commitment or provision contained
in the AGREEMENT;

(c) Legal action, complaints, procedures, investigations, lawsuits or
settlements related to paragraphs (a) and (b) of this clause causing damage to
BUYERS or ISSUER.

(d) Not attend or untimely attend any of the contingencies indicated in Clause
Fourth above.

If any third party files or attempts any complaint or any other proceeding
against ISSUER or BUYERS, that may cause damages for which BUYERS or ISSUER have
the right to request payment of an indemnity from SELLERS in proportion to the
SHARES sold by each of them under the AGREEMENT, BUYERS must notify SELLERS at
the official address provided in Clause Eighth within 30 (thirty) business days
after being informed of the event that might originate such damages. Such notice
must include documents and information necessary for SELLERS to defend such
complaint, claim or proceeding before the competent authorities. For such end,
through ISSUER, BUYERS shall grant the necessary powers of attorney to the
person jointly indicated by SELLERS no later than the business day after they
receive the notice provided for in this paragraph,

                                     [STAMP]

                                       12

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in order to assume the corresponding defense. In case SELLERS do not provide
BUYERS and ISSUER the name of the professional in charge of the defense, BUYERS
may designate any professional to be in charge of the defense, in the
understanding that in such case, SELLERS shall be bound to pay for resulting
damages, as the case may be, which shall not exceed the amount established in
Clause Second of this Agreement. In case ISSUER does not, within the term
provided in this Clause, grant the powers of attorney to the professional
designated by SELLERS, SELLERS shall, as the case may be, be released from
having to pay the indemnification referred to in this Clause.

SIXTH: VALID TERM OF REPRESENTATIONS AND INDEMNIFICATIONS. The representations
made by SELLERS, as well as the indemnifications BUYERS and ISSUER have a right
to, as the case may be, as contained in the AGREEMENT, shall be in effect only
during five (5) years after the date when this AGREEMENT is signed.

SEVENTH: RESTORATION IN CASE OF DISPOSSESSION. SELLERS shall BE liable before
BUYERS for restoration in case of dispossession according to Article 2119 and
other related and applicable articles of the Federal Civil Code and correlated
articles of the other civil codes applicable in the states of

                                     [STAMP]

                                       13

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the Mexican Republic.

EIGHTH NOTICES: All notices, requests, instructions or any other communication
(jointly, the "Notices), which according to the AGREEMENT must be issued to the
other parties, shall be in writing, made at the official addresses provided
below:

BUYERS:
Ernesto Javier Gonzalez Castro
Bartolache No. 1810, Col. Del Valle C.P. 03100
Deleg. Benito Juarez, Mexico, D.F.

Mauricio Ramon Arevalo Mercado
Manuel Gutierrez Najera manzana 8 lote 49
Col. Filiberto Gomez, Chimalhuacan, Estado de Mexico
C.P. 56349

SELLERS:
Texas Oil & Chemical Co. II, Inc., and Nicholas N. Carter 7752 FM 418, Silsbe,
Texas 77656

Either one of the parties may change such official addressed by issuing written
notice to the other parties as provided in this Clause Eighth (in the
understanding that such change shall be valid once the notice is actually
received by the other parties).

All notices shall be considered received: (i) if received through personal
delivery; (ii) the moment when sending prior confirmation of receipt, when
transmitted by tax with electronic confirmation; and (iii) on the second
business day

                                     [STAMP]

                                       14

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after having been delivered to a recognized night delivery service (DHL or
FEDEX).

NINTH: OBLIGATIONS FOR BUYERS: BUYERS bind themselves to hold a Shareholders
Meeting of the ISSUER within 10 days after the date when this Agreement is
signed, to resolve on all of the following:

I.- Transfer of shares of the Corporation.

II.- Resignation by Nicholas N. Carter as member of the Board of Directors,
appointment of the new Board of Directors, as well as appointment of the
Statutory Auditor of the Corporation.

III.- Revocation and granting of powers of attorney.

IV.- Proposal, discussion and, as the case may be, approval to designate special
delegates for the Shareholders Meeting.

BUYERS bind themselves that within 15 (fifteen) business days after the date of
execution of this AGREEMENT they shall provide SELLERS a certified copy of the
public instrument legalizing the resolutions disclosed in this Clause.

TENTH: APPLICABLE LAWS. For construction, fulfillment and execution of the
AGREEMENT, the parties bind themselves to provisions of the Code of Commerce and
supplementary

                                     [STAMP]

                                       15

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ordinances.

ELEVENTH: CONTROVERSIES. For all matters regarding construction and/or
fulfillment of this AGREEMENT the parties expressly bind themselves to the
jurisdiction of the competent courts of the City of Mexico, Federal District,
and each of the parties hereby waives any other forum or jurisdiction that might
correspond to itself by reason of its current or any further official address.

TWELFTH: INTEGRAL AGREEMENT. The parties recognize this AGREEMENT as the coming
of minds between themselves. All previous communications, promises and
agreements are considered revoked, ended and substituted by the content of this
AGREEMENT.

THIRTEENTH: ASSIGNMENT. Rights and obligations derived from the AGREEMENT may
not be assigned, nor in any other manner conveyed without prior written consent
by the other parties.

FOURTEENTH: TAXES. Regarding the obligation for BUYERS to withhold against the
individual seller, NICHOLAS N. CARTER, 20% the price of the operation as
provisional payment of Federal Income Tax, according to paragraph four of
Article 154 of the Federal Income Tax Law, such withholding is

                                     [STAMP]

                                       16

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applied and shall be filed before the corresponding revenue office. In relation
to selling corporation, TEXAS OIL & CHEMICAL CO. II, INC., which files taxes
according to Title II of the Federal Income Tax Law and proves its corresponding
registration, does not have to apply BUYERS any withholding, and therefore, must
accumulate and file the total corresponding income during the year when
transferred.

FIFTEENTH: MODIFICATIONS. The AGREEMENT may not be modified except through
written consent by the parties.

SIXTEENTH: NO FAULTS. The parties declare they are aware of the value and legal
scope of this AGREEMENT, and therefore manifest they have granted each other the
opportunity to explain and clarify the content of its clauses to each other.
They also acknowledge that what has been agreed results from their free and
spontaneous disposition, and therefore, there is not violence, error or any
situation that might invalidate their consent.

SEVENTEENTH: VALIDITY AND EFFICACY. The AGREEMENT shall be valid and have full
legal effect between the parties when signed by all the SELLERS and the BUYERS.

EIGHTEENTH: COPIES. The AGREEMENT shall be signed in 3

                                     [STAMP]

                                       17

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(three) copies, each considered an original, to be distributed among the
appearing parties and for control by the ISSUER.

Having been fully read and manifested their express consent to it, the parties
sign this AGREEMENT in the City of Mexico, Federal District, on June 9, 2005.

                                     SELLERS

(illegible signature)                             (illegible signature)
----------------------------                      ---------------------
Texas Oil & Chemical Co. II,                      Nicholas N. Carter
Inc., represented by
Nicholas N. Carter

                                     BUYERS

(illegible signature)                             (illegible signature)
----------------------------                      ------------------------------
Ernesto Javier Gonzalez                           Mauricio Ramon Arevalo
Castro                                            Mercado

                                    WITNESSES

(illegible signature)                             (illegible signature)
----------------------------                      ------------------------------
Name: Leopoldo Escobar L.                         Name: Gerardo Maldonado

                                     [STAMP]

                                       18

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The undersigned, Kristin Dagny O'Hea de Langarica, Litorales 69, Col. Las
Aguilas, Mexico, D.F., 5593-0471, who have been authorized by the Federal
Judiciary Council (Consejo de la Judicatura Federal) to act as an expert
translator before all courts belonging to the Judicial Branch of the Federal
Government of Mexico, certify that the foregoing is a true and exact translation
of the attached document.

Mexico, D.F., June 21, 2005.

/s/ Kristin Dagny O'Hea de Langarica
------------------------------------
    Kristin Dagny O'Hea de Langarica

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                                 ATTACHMENT "I"

                              Accounts Receivable

                                     [STAMP]

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                  LIST OF ACCOUNTS RECEIVABLE PER MAY 31, 2005

<TABLE>
<CAPTION>
                                                 A.P.
<S>                                              <C>             <C>        <C>
PRODUCTOS QUIMICOS GUTIERREZ, S.A. DE C.V.       $742,894.54     $10.8699   $68,436,19
GRUPO PETROPOL, S.A. DE C.V.                                                $15,343.87
                                                                            ----------
                                                                            $83,780.06
</TABLE>

                                     [STAMP]

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The undersigned, Kristin Dagny O'Hea de Langarica, Litorales 69, Col. Las
Aguilas, Mexico, D.F., 5593-0471, who have been authorized by the Federal
Judiciary Council (Consejo de la Judicatura Federal) to act as an expert
translator before all courts belonging to the Judicial Branch of the Federal
Government of Mexico, certify that the foregoing is a true and exact translation
of the attached document.

Mexico, D.F., June 21, 2005.

/s/ Kristin Dagny O'Hea de Langarica
------------------------------------
    Kristin Dagny O'Hea de Langarica