EXHIBIT 10.2

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GUARANTY

This Guaranty (this “Agreement”) dated as of March 10, 2006 is made by Frontier
Oil Corporation, a Wyoming corporation (the “Guarantor”), in favor of Utexam
Limited (“Utexam”). Each of the Parties may be referred to herein individually
as a “Party” and collectively as the “Parties.”
 
RECITALS
 
1. This Agreement is being executed and delivered in connection with that
certain Master Crude Oil Purchase and Sale Contract dated as of even date
herewith (the “Purchase and Sale Contract”) by and among Utexam, as seller, and
Frontier Oil & Refining Company, as purchaser (the “Purchaser”).
 
2. The Guarantor represents it is the parent company of the Purchaser.
 
3. The Guarantor acknowledges that it will substantially benefit from the
Purchase and Sale Contract.
 
4 To induce Utexam to enter into the Purchase and Sale Contract, the Purchaser
desires that the Guarantor guarantee the Purchaser’s payment and performance
under the Purchase and Sale Contract.
 
5. The Guarantor desires to guarantee the Purchaser’s payment and performance
under the Purchase and Sale Contract upon the terms and conditions set forth
herein.
 
AGREEMENT
 
For and in consideration of the premises and mutual covenants herein contained
and other good and valuable consideration (the receipt and sufficiency of which
is hereby acknowledged), the Guarantor does hereby stipulate and agree as
follows:
 
 
1. The Guaranty. Subject to the last sentence of this Section 1, the Guarantor
hereby irrevocably and unconditionally guarantees to Utexam the full and timely
payment and performance and discharge by the Purchaser of all obligations and
liabilities of the Purchaser now existing or hereafter arising under the
Purchase and Sale Contract (the “Guaranteed Obligations”) and hereby agrees that
if the Purchaser shall fail timely to pay, perform and discharge in full any
obligation or liability in accordance with the terms of the Purchase and Sale
Contract, the Guarantor shall be liable to Utexam for such obligation or
liability, and, as such, if the Purchaser fails to pay, perform and discharge
any of the Guaranteed Obligations in accordance with the terms of the Purchase
and Sale Contract, the Guarantor will, within three (3) days after written
notice of such failure to the Guarantor by Utexam, pay, perform and discharge
any such Guaranteed Obligation, as the case may be, as such payment, performance
and discharge is required to be made or done by the Purchaser pursuant to the
terms of the Purchase and Sale Contract. The guarantee in the preceding sentence
is an absolute, present and continuing guarantee of payment and performance of
obligations and not of collectibility and is in no way conditional or contingent
upon any attempt to collect from the Purchaser or upon any other action,
occurrence or circumstance whatsoever. It shall not be necessary for Utexam, in
order to enforce such payment and performance by the Guarantor, first to
institute suit or exhaust its remedies against the Purchaser or any other person
liable with respect to any Guaranteed Obligations.
 
 
2. Obligations Absolute. The obligations of the Guarantor to Utexam hereunder
shall be absolute, continuing and unconditional and shall not be released,
discharged or in any way affected by (except to the extent the Purchaser is so
affected other than as set forth in (e) and (j) below), any of the following:
 
 
(a) any amendment to, modification of, or supplement to the Purchase and Sale
Contract or any assignment or transfer of any rights or obligations thereunder;
 
 
(b) any release, consent or waiver, by operation of law or otherwise, of the
payment, performance or observance by the Purchaser or any other person of any
express or implied agreement, covenant, term, obligation or condition under the
Purchase and Sale Contract;
 
 
(c) any extension of the time for the payment of all or any portion of any sums
payable under the Purchase and Sale Contract or the extension of time for the
payment or performance of any obligations under, arising out of or in connection
with the Purchase and Sale Contract;
 
 
(d) any failure, omission, delay or lack of diligence on the part of Utexam or
any other person to enforce, assert or exercise, or any waiver of, any right,
privilege, power or remedy conferred on Utexam or any other person by the
Purchase and Sale Contract, or any action on the part of Utexam or such other
person granting indulgence or extension of any kind;
 
 
(e) any bankruptcy, insolvency, readjustment, composition, liquidation,
dissolution or similar proceeding or any other defense that may arise in
connection with any such proceeding with respect to the Purchaser, the Guarantor
or any other person;
 
 
(f) any change in the corporate or partnership structure, existence or ownership
of the Guarantor, the Purchaser or Utexam, or any sale, lease or transfer of any
or all of the assets of the Guarantor or the Purchaser to any person;
 
 
(g) any failure on the part of the Purchaser for any reason to comply with or
perform any of the terms of any other agreement with the Guarantor;
 
 
(h) the settlement or compromise of any Guaranteed Obligations;
 
(i) any law, regulation or order hereafter in effect in any jurisdiction
affecting any of the rights under or terms of the Purchase and Sale Contract; or
 
(j) any other circumstance that might otherwise constitute a legal or equitable
discharge of the Purchaser.
 
 
3. Waiver. With respect to Utexam, the Guarantor unconditionally waives, to the
fullest extent permitted by law: (a) notice of acceptance hereof, of any action
taken or omitted in reliance hereon, of demand, and of the defaults by the
Purchaser in the payment or performance of any Guaranteed Obligations, and of
any of the matters referred to in Section 2; (b) all notices that may otherwise
be required by statute, rule of law or otherwise to preserve any of the rights
of Utexam against the Guarantor, including presentment to or demand for payment
from the Purchaser or the Guarantor, or notice to the Purchaser of claims with a
court in the event of the bankruptcy of the Purchaser; and (c) any requirement
of diligence on the part of Utexam.
 
 
4. Reinstatement of Guaranty. This Agreement shall continue to be effective, or
be reinstated, as the case may be, if and to the extent at any time any payment,
in whole or in part, made by the Purchaser or the Guarantor to Utexam in respect
of any Guaranteed Obligations is rescinded or must otherwise be restored or
returned by Utexam upon the insolvency, bankruptcy, dissolution, liquidation or
reorganization of the Purchaser, or upon or as a result of the appointment of a
custodian, receiver, trustee or other officer with similar powers with respect
to the Purchaser or any substantial part of its property, or otherwise, all as
though such payments had not been made and, to the extent permitted by
applicable law, in such event, the Guarantor shall be liable to Utexam for an
amount equal to the payment that has been rescinded or returned, and, as such,
the Guarantor shall pay to Utexam such amount equal to the payment that has been
rescinded or returned within three (3) days after written demand therefor has
been made to the Guarantor by Utexam. Utexam shall not be required to litigate
or otherwise dispute its obligation to make such repayments if it in good faith
believes that such obligation exists and has so made such repayments.
 
 
5. Representations, Covenants and Warranties of the Guarantor. As of the date
hereof, the Guarantor represents, covenants and warrants that it is Solvent (as
defined below) and able to pay its respective debts as they mature, and owns
assets and property which in the aggregate have a fair value greater than the
amount required to pay its debts as they mature. “Solvent” means with respect to
the Guarantor (a) the fair value of the property of the Guarantor exceeds its
total liabilities including, without limitation, contingent liabilities, (b) the
present fair saleable value of the assets of the Guarantor is not less than the
amount that will be required to pay its probable liability on its debts as they
become absolute and matured, (c) the Guarantor does not intend to, and does not
believe that it will, incur debts or liabilities beyond its ability to pay as
such debts and liabilities mature and (d) the Guarantor is not engaged, and is
not about to engage, in business or a transaction for which its property would
constitute unreasonably small capital.
 

6. Subordination. The Subordinated Debt (as defined below) is expressly
subordinated to the full and final payment of the Guaranteed Obligations. The
Guarantor may accept payment of Subordinated Debt so long as no default or
circumstance that with the passage of time would result in a default exists, but
the Guarantor agrees not to accept any payment of any Subordinated Debt from the
Purchaser if a default or circumstance that with the passage of time would
result in a default exists under the Purchase and Sale Contract. If the
Guarantor receives any payment of any Subordinated Debt in violation of the
foregoing, the Guarantor shall hold that payment in trust for Utexam and
promptly turn it over to Utexam, in the form received (with any necessary
endorsements), to be applied to the Guaranteed Obligations. “Subordinated Debt”
means all present and future payment obligations of the Purchaser to the
Guarantor, whether those obligations are (a) direct, indirect, fixed,
contingent, liquidated, unliquidated, joint, several, or joint and several, (b)
due or to become due to the Guarantor, (c) held by or are to be held by the
Guarantor, (d) created directly or acquired by assignment or otherwise, or (e)
evidenced in writing.
 
7. Subrogation and Contribution. Until all obligations under the Purchase and
Sale Contract have expired or been canceled, and the Guaranteed Obligations have
been fully paid and performed (the “Deferment Date”) (a) the Guarantor may not
assert, enforce, or otherwise exercise any right of subrogation to any of the
rights of Utexam or any other beneficiary against the Purchaser or any other
obligor on the Guaranteed Obligations or any right of recourse, reimbursement,
subrogation, contribution, indemnification, or similar right against the
Purchaser or any other obligor on any Guaranteed Obligations or any guarantor of
it, and (b) the Guarantor defers all of the foregoing rights (whether they arise
in equity, under contract, by statute, under common law, or otherwise) until the
Deferment Date.
 
 
6. Notices. All notices, requests, demands, claims, and other communications
hereunder ("Notice") shall be in writing and shall be (i) delivered personally,
(ii) mailed by registered or certified mail, postage prepaid and return receipt
requested, (iii) by facsimile or (iv) by electronic mail as set forth below:
 

If to the Guarantor:  Frontier Oil Corporation
10000 Memorial Drive, Suite 600
Houston, TX 77024-0616
Attn: Doug Aron, Vice President - Corporate Finance
Facsimile: 713-688-0616
Telephone: 713-688-5628

with a copy to:   Frontier Oil Corporation
10000 Memorial Drive, Suite 600
Houston, TX 77024-0616
Attn: Currie Bechtol, General Counsel
Facsimile: 713-688-0616
Telephone: 713-688-0881

If to Utexam:    Utexam Limited
5 George’s Dock
IFSC
Dublin 1, Ireland
Attn: Mr. Frank Carey
Attn: Mr. Clive Christie
Facsimile: 353.1.612.51.05
Telephone: 353.1.612.50.00

with a copy to:   BNP Paribas
Energy Commodities Export Project
787 Seventh Avenue
New York, NY 10019
Attn: Keith Cox
Facsimile: 212-841-2536
Telephone: 212-841-2575

Notice given by personal delivery or mail shall be effective upon actual
receipt. Notice given by telecopy or electronic mail shall be effective upon
actual receipt if received during the recipient's normal business hours, or at
the beginning of the recipient's next business day after receipt if not received
during the recipient's normal business hours. All Notices by facsimile or
electronic mail shall be confirmed promptly after transmission in writing by
certified mail or personal delivery. Any Party may change the address to which
Notices are to be delivered by giving the other Party notice in the manner
herein set forth.
 
 
7. Construction. The Parties have participated jointly in the negotiation and
drafting of this Agreement. In the event an ambiguity or question of intent or
interpretation arises, this Agreement shall be construed as if drafted jointly
by the Parties and no presumption or burden of proof shall arise favoring or
disfavoring any Party by virtue of the authorship of any of the provisions of
this Agreement. Any reference to any federal, state, local, or foreign statute
or law shall be deemed also to refer to all rules and regulations promulgated
thereunder, unless the context requires otherwise. The word “including” shall
mean including without limitation. All personal pronouns used in this Agreement,
whether used in the masculine, feminine or neuter gender, shall include all
other genders; the singular shall include the plural, and vice versa. All
references herein to Exhibits, Schedules, Articles, Sections or subdivisions
thereof shall refer to the corresponding Exhibits, Schedules, Article, Section
or subdivision thereof of this Agreement unless specific reference is made to
such exhibits, articles, sections or subdivisions of another document or
instrument. The terms “herein,” “hereby,” “hereunder,” “hereof,” “hereinafter,”
and other equivalent words refer to this Agreement in its entirety and not
solely to the particular portion of the Agreement in which such word is used.
 
 
8. Severability. Any term or provision of this Agreement that is invalid or
unenforceable in any situation in any jurisdiction shall not affect the validity
or enforceability of the remaining terms and provisions hereof or the validity
or enforceability of the offending term or provision in any other situation or
in any other jurisdiction.
 
 
9. Entire Agreement; Amendment. THIS AGREEMENT (INCLUDING THE DOCUMENTS REFERRED
TO HEREIN) CONSTITUTES THE ENTIRE AGREEMENT AMONG THE PARTIES AND SUPERSEDES ANY
PRIOR UNDERSTANDINGS, AGREEMENTS, OR REPRESENTATIONS BY OR AMONG THE PARTIES,
WRITTEN OR ORAL, TO THE EXTENT THEY HAVE RELATED IN ANY WAY TO THE SUBJECT
MATTER HEREOF. No amendment of any provision of this Agreement shall be valid
unless the same shall be in writing and signed by the Guarantor and Utexam.
 
 
10. Term of Agreement. This Agreement and all guarantees, covenants and
agreements of the Guarantor contained herein shall continue in full force and
effect and shall not be discharged until the earlier to occur of: (i) all of the
Purchase and Sale Contract shall have terminated or expired, or all of the
Guaranteed Obligations shall be indefeasibly paid in full in cash or otherwise
performed and discharged in full, or (ii) upon written consent of the Guarantor
and Utexam.
 
 
11. Survival of Representations and Warranties. All representations and
warranties contained herein or made in writing or on behalf of the Guarantor in
connection herewith shall survive the execution and delivery of this Agreement.
 
 
12. Governing Law. THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE DOMESTIC LAWS OF THE STATE OF NEW YORK WITHOUT GIVING EFFECT
TO ANY CHOICE OR CONFLICT OF LAW PROVISION OR RULE (WHETHER OF THE STATE OF NEW
YORK OR ANY OTHER JURISDICTION) THAT WOULD CAUSE THE APPLICATION OF THE LAWS OF
ANY JURISDICTION OTHER THAN THE STATE OF NEW YORK.
 

13. Attorneys’ Fees. In the event of any litigation or other proceedings to
enforce this Agreement, the prevailing Party or Parties shall be entitled to
recover all reasonable attorneys’ fees and expenses incurred in connection
therewith.
 
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IN WITNESS WHEREOF, the Guarantor has caused this Agreement to be duly executed
and delivered as of the date and year first written in the preamble to this
Agreement.
 

 
FRONTIER OIL CORPORATION

By: 
Doug S. Aron
Vice President - Corporate Finance

ACKNOWLEDGED AND ACCEPTED

UTEXAM LIMITED

By: 
Name: 
Title: 

By: 
Name: 
Title: