Exhibit 10.12


                             GUARANTY BY CORPORATION

     This Guaranty, dated as of May 23, 2006, is made by Tradestar Services,
Inc., a Nevada corporation (the "Guarantor"), for the benefit of Wells Fargo
Bank, National Association (with its participants, successors and assigns, the
"Lender"), acting through its Wells Fargo Business Credit operating division.

     The Lender, Tradestar Construction Services, Inc., a New Mexico corporation
("Tradestar"), and Petroleum Engineers, Inc., a Louisiana corporation
("Petroleum Engineers", and together with Tradestar, the "Borrower"), are
parties to a Credit and Security Agreement of even date herewith (as the same
may be amended, supplemented or restated from time to time, the "Credit
Agreement") pursuant to which the Lender may make advances and extend other
financial accommodations to the Borrower.

     As a condition to extending such credit to the Borrower, the Lender has
required the execution and delivery of this Guaranty.

     ACCORDINGLY, the Guarantor, in consideration of the premises and other good
and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, hereby agrees as follows:

     1. Definitions. All terms defined in the Credit Agreement that are not
otherwise defined herein shall have the meanings given them in the Credit
Agreement.

     2. Indebtedness Guaranteed. The Guarantor hereby absolutely and
unconditionally guarantees to the Lender the full and prompt payment when due,
whether at maturity or earlier by reason of acceleration or otherwise, of (i)
the Obligations and (ii) each and every other sum now or hereafter owing to the
Lender by the Borrower, including but not limited to, debts, liabilities and
obligations arising out of loans, credit transactions, financial accommodations,
discounts, purchases of property or other transactions with the Borrower or for
the Borrower's account or out of any other transaction or event, owed to the
Lender or owed to others by reason of participations granted to or interests
acquired or created for or sold to them by the Lender, in each case whether now
existing or hereafter arising, whether arising directly in a transaction or
event involving the Lender or acquired by the Lender from another by purchase or
assignment or as collateral security, whether owed by the Borrower as drawer,
maker, endorser, accommodation party, guarantor, principal, surety or as a
member of any partnership, syndicate, association or group or in any other
capacity, whether absolute or contingent, direct or indirect, primary or
secondary, sole, joint, several or joint and several, secured or unsecured, due
or not due, contractual, tortious or statutory, liquidated or unliquidated,
arising by agreement or imposed by law or otherwise (all of said sums being
hereinafter called the "Indebtedness").

     3. Guarantor's Representations and Warranties. The Guarantor represents and
warrants to the Lender that (i) the Guarantor is a corporation, duly organized
and existing in good standing and has full power and authority to make and
deliver this Guaranty; (ii) the execution, delivery and performance of this
Guaranty by the Guarantor have been duly authorized by all necessary action of
its directors and shareholders and do not and will not violate the provisions

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of, or constitute a default under, any presently applicable law or its
Constituent Documents or any agreement presently binding on it; (iii) this
Guaranty has been duly executed and delivered by the authorized Officers of the
Guarantor and constitutes its lawful, binding and legally enforceable
obligation; and (iv) the authorization, execution, delivery and performance of
this Guaranty do not require notification to, registration with, or consent or
approval by, any federal, state or local regulatory body or administrative
agency. The Guarantor represents and warrants to the Lender that the Guarantor
has a direct and substantial economic interest in the Borrower and expects to
derive substantial benefits therefrom and from any loans, credit transactions,
financial accommodations, discounts, purchases of property and other
transactions and events resulting in the creation of the Indebtedness guarantied
hereby, and that this Guaranty is given for a corporate purpose. The Guarantor
agrees to rely exclusively on the right to revoke this Guaranty prospectively as
to future transactions, in accordance with paragraph 4, if at any time, in the
opinion of the directors or officers, the benefits then being received by the
Guarantor in connection with this Guaranty are not sufficient to warrant the
continuance of this Guaranty as to the future Indebtedness of the Borrower.
Accordingly, so long as this Guaranty is not revoked prospectively in accordance
with paragraph 4, the Lender may rely conclusively on a continuing warranty,
hereby made, that the Guarantor continues to be benefited by this Guaranty and
the Lender shall have no duty to inquire into or confirm the receipt of any such
benefits, and this Guaranty shall be effective and enforceable by the Lender
without regard to the receipt, nature or value of any such benefits.

     4. Unconditional Nature. No act or thing need occur to establish the
Guarantor's liability hereunder, and no act or thing, except full payment and
discharge of all of the Indebtedness, shall in any way exonerate the Guarantor
hereunder or modify, reduce, limit or release the Guarantor's liability
hereunder. This is an absolute, unconditional and continuing guaranty of payment
of the Indebtedness and shall continue to be in force and be binding upon the
Guarantor, whether or not all of the Indebtedness is paid in full, until this
Guaranty is revoked prospectively as to future transactions, by written notice
actually received by the Lender, and such revocation shall not be effective as
to the amount of Indebtedness existing or committed for at the time of actual
receipt of such notice by the Lender, or as to any renewals, extensions,
refinancings or refundings thereof.

     5. Dissolution or Insolvency of Guarantor. The dissolution or adjudication
of bankruptcy of the Guarantor shall not revoke this Guaranty, except upon
actual receipt of written notice thereof by the Lender and only prospectively,
as to future transactions, as herein set forth. If the Guarantor shall be
dissolved or shall be or become insolvent (however defined), then the Lender
shall have the right to declare immediately due and payable, and the Guarantor
will forthwith pay to the Lender, the full amount of all of the Indebtedness
whether due and payable or unmatured. If the Guarantor voluntarily commences or
there is commenced involuntarily against the Guarantor a case under the United
States Bankruptcy Code, the full amount of all Indebtedness, whether due and
payable or unmatured, shall be immediately due and payable without demand or
notice thereof.

     6. Subrogation, etc. The Guarantor hereby waives all rights that the
Guarantor may now have or hereafter acquire, whether by subrogation,
contribution, reimbursement, recourse, exoneration, contract or otherwise, to
recover from the Borrower or from any property of the Borrower any sums paid
under this Guaranty. The Guarantor will not exercise or enforce any right of

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contribution to recover any such sums from any person who is a co-obligor with
the Borrower or a guarantor or surety of the Indebtedness or from any property
of any such person until all of the Indebtedness shall have been fully paid and
discharged.

     7. Enforcement Expenses. The Guarantor will pay or reimburse the Lender for
all costs, expenses and attorneys' fees paid or incurred by the Lender in
endeavoring to collect and enforce the Indebtedness and in enforcing this
Guaranty.

     8. Lender's Rights. The Lender shall not be obligated by reason of its
acceptance of this Guaranty to engage in any transactions with or for the
Borrower. Whether or not any existing relationship between the Guarantor and the
Borrower has been changed or ended and whether or not this Guaranty has been
revoked, the Lender may enter into transactions resulting in the creation or
continuance of the Indebtedness and may otherwise agree, consent to or suffer
the creation or continuance of any of the Indebtedness, without any consent or
approval by the Guarantor and without any prior or subsequent notice to the
Guarantor. The Guarantor's liability shall not be affected or impaired by any of
the following acts or things (which the Lender is expressly authorized to do,
omit or suffer from time to time, both before and after revocation of this
Guaranty, without consent or approval by or notice to the Guarantor): (i) any
acceptance of collateral security, guarantors, accommodation parties or sureties
for any or all of the Indebtedness; (ii) one or more extensions or renewals of
the Indebtedness (whether or not for longer than the original period) or any
modification of the interest rates, maturities, if any, or other contractual
terms applicable to any of the Indebtedness or any amendment or modification of
any of the terms or provisions of any loan agreement or other agreement under
which the Indebtedness or any part thereof arose; (iii) any waiver or indulgence
granted to the Borrower, any delay or lack of diligence in the enforcement of
the Indebtedness or any failure to institute proceedings, file a claim, give any
required notices or otherwise protect any of the Indebtedness; (iv) any full or
partial release of, compromise or settlement with, or agreement not to sue, the
Borrower or any guarantor or other person liable in respect of any of the
Indebtedness; (v) any release, surrender, cancellation or other discharge of any
evidence of the Indebtedness or the acceptance of any instrument in renewal or
substitution therefor; (vi) any failure to obtain collateral security (including
rights of setoff) for the Indebtedness, or to see to the proper or sufficient
creation and perfection thereof, or to establish the priority thereof, or to
preserve, protect, insure, care for, exercise or enforce any collateral
security; or any modification, alteration, substitution, exchange, surrender,
cancellation, termination, release or other change, impairment, limitation, loss
or discharge of any collateral security; (vii) any collection, sale, lease or
disposition of, or any other foreclosure or enforcement of or realization on,
any collateral security; (viii) any assignment, pledge or other transfer of any
of the Indebtedness or any evidence thereof; (ix) any manner, order or method of
application of any payments or credits upon the Indebtedness; and (x) any
election by the Lender under Section 1111(b) of the United States Bankruptcy
Code. The Guarantor waives any and all defenses and discharges available to a
surety, guarantor or accommodation co-obligor.

     9. Waivers by Guarantor. The Guarantor waives any and all defenses, claims,
setoffs and discharges of the Borrower, or any other obligor, pertaining to the
Indebtedness, except the defense of discharge by payment in full. Without
limiting the generality of the foregoing, the Guarantor will not assert, plead
or enforce against the Lender any defense of waiver, release, discharge or
disallowance in bankruptcy, statute of limitations, res judicata, statute of

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frauds, anti-deficiency statute, fraud, incapacity, minority, usury, illegality
or unenforceability which may be available to the Borrower or any other person
liable in respect of any of the Indebtedness, or any setoff available against
the Lender to the Borrower or any other such person, whether or not on account
of a related transaction. The Guarantor expressly agrees that the Guarantor
shall be and remain liable for any deficiency remaining after foreclosure of any
mortgage or security interest securing the Indebtedness, whether or not the
liability of the Borrower or any other obligor for such deficiency is discharged
pursuant to statute or judicial decision. The liability of the Guarantor shall
not be affected or impaired by any voluntary or involuntary liquidation,
dissolution, sale or other disposition of all or substantially all of the
assets, marshalling of assets and liabilities, receivership, insolvency,
bankruptcy, assignment for the benefit of creditors, reorganization,
arrangement, composition or readjustment of, or other similar event or
proceeding affecting, the Borrower or any of its assets. The Guarantor will not
assert, plead or enforce against the Lender any claim, defense or setoff
available to the Guarantor against the Borrower. The Guarantor waives
presentment, demand for payment, notice of dishonor or nonpayment and protest of
any instrument evidencing the Indebtedness. The Lender shall not be required
first to resort for payment of the Indebtedness to the Borrower or other
persons, or their properties, or first to enforce, realize upon or exhaust any
collateral security for the Indebtedness, before enforcing this Guaranty.
Guarantor waives the benefits of Arizona Revised Statutes Sections 12-1641,
12-1642, 33-814 and 12-1566.

     10. If Payments Set Aside, etc. If any payment applied by the Lender to the
Indebtedness is thereafter set aside, recovered, rescinded or required to be
returned for any reason (including, without limitation, the bankruptcy,
insolvency or reorganization of the Borrower or any other obligor), the
Indebtedness to which such payment was applied shall for the purpose of this
Guaranty be deemed to have continued in existence, notwithstanding such
application, and this Guaranty shall be enforceable as to such Indebtedness as
fully as if such application had never been made.

     11. Additional Obligation of Guarantor. The Guarantor's liability under
this Guaranty is in addition to and shall be cumulative with all other
liabilities of the Guarantor to the Lender as guarantor, surety, endorser,
accommodation co-obligor or otherwise of any of the Indebtedness or obligation
of the Borrower, without any limitation as to amount, unless the instrument or
agreement evidencing or creating such other liability specifically provides to
the contrary.

     12. Financial Information. The Guarantor will deliver to the Lender all
financial information concerning the Guarantor required to be delivered under
the Credit Agreement.

     13. No Duties Owed by Lender. The Guarantor acknowledges and agrees that
the Lender (i) has not made any representations or warranties with respect to,
(ii) does not assume any responsibility to the Guarantor for, and (iii) has no
duty to provide information to the Guarantor regarding, the enforceability of
any of the Indebtedness or the financial condition of the Borrower or any
guarantor. The Guarantor has independently determined the creditworthiness of
the Borrower and the enforceability of the Indebtedness and until the
Indebtedness is paid in full will independently and without reliance on the
Lender continue to make such determinations.

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     14. Miscellaneous. This Guaranty shall be effective upon delivery to the
Lender, without further act, condition or acceptance by the Lender, shall be
binding upon the Guarantor and the successors and assigns of the Guarantor and
shall inure to the benefit of the Lender and its participants, successors and
assigns. Any invalidity or unenforceability of any provision or application of
this Guaranty shall not affect other lawful provisions and application thereof,
and to this end the provisions of this Guaranty are declared to be severable.
This Guaranty may not be waived, modified, amended, terminated, released or
otherwise changed except by a writing signed by the Guarantor and the Lender.
This Guaranty shall be governed by and construed in accordance with the
substantive laws (other than conflict laws) of the State of Colorado. The
Guarantor hereby (i) consents to the personal jurisdiction of the state and
federal courts located in the State of Colorado in connection with any
controversy related to this Guaranty; (ii) waives any argument that venue in any
such forum is not convenient, (iii) agrees that any litigation initiated by the
Lender or the Guarantor in connection with this Guaranty may be venued in either
the state or federal courts located in the City and County of Denver, Colorado;
and (iv) agrees that a final judgment in any such suit, action or proceeding
shall be conclusive and may be enforced in other jurisdictions by suit on the
judgment or in any other manner provided by law.

     15. Waiver of Jury Trial. THE GUARANTOR HEREBY IRREVOCABLY WAIVES ALL
RIGHTS TO TRIAL BY JURY IN ANY ACTION, PROCEEDING OR COUNTERCLAIM ARISING OUT
OF, BASED ON OR PERTAINING TO THIS GUARANTY.

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     IN WITNESS WHEREOF, this Guaranty has been duly executed by the Guarantor
the date first written above.


                                               TRADESTAR SERVICES, INC.


                                               By: /s/ Frederick A. Huttner
                                                   ------------------------
                                               Its: Secretary and Treasurer

                                               Address:
                                               3451 Candelaria, NE, Suite A
                                               Albuquerque, New Mexico  87107


STATE OF TEXAS    )
                  ) ss.
COUNTY OF HARRIS  )

     The foregoing instrument was acknowledged before me this 22nd day of May,
2006 by Frederick A. Huttner, the Secretary and Treasurer of Tradestar Services,
Inc., a Nevada corporation, on behalf of the corporation.


                                                 /s/ Kim M. Green
                                                 ----------------
                                                 Notary Public

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