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BOEING CAPITAL CORPORATION

                                          Loan and Security Agreement No. 3548-2

                             UNCONDITIONAL GUARANTY

For value received and in order to induce Boeing Capital Corporation, a Delaware
corporation ("Lender"), to enter into, accept or acquire a certain Loan and
Security Agreement dated as June 11, 1999 (hereinafter with all present and
future, amendments, addenda and riders thereto referred to as the "Loan") with
The First Security Bank, N.A., not in its individual capacity but as Trustee
under that certain Bell 412 Peru Trust No. 1, a Utah trust ("Debtor"), and/or to
advance monies or extend or continue to extend credit to or for the benefit of
Debtor, under the Loan or otherwise, the undersigned hereby absolutely,
irrevocably and unconditionally guarantees to Lender (i) the prompt and full
payment when due, by acceleration or otherwise, of all sums now or at any time
hereafter due from Debtor to Lender, under the Loan or otherwise and agrees to
pay any and all expenses (including reasonable counsel fees and expenses)
incurred by Lender in enforcing any rights under this Guaranty, and (ii) the
prompt, full and faithful performance and discharge by Debtor of each and every
obligation and warranty of Debtor set forth in the Loan (collectively "Debtor's
Obligations").

This Guaranty is absolute, unconditional and continuing and shall remain in
effect until all of Debtor's Obligations have been paid, performed and
discharged regardless of the enforceability of Debtor's Obligations and
regardless of any law, regulation or decree now or hereafter in effect which
might in any manner affect Debtor's Obligations. The death or bankruptcy of the
undersigned or of Debtor shall not terminate this Guaranty or any obligations
hereunder. The liability of the undersigned hereunder shall in no event be
affected or impaired by any renewals, amendments, modifications or supplements
of or to the Loan, or by any extensions, forebearances, compromises or releases
of any of Debtor's Obligations, any of Lender's rights under the Loan or any
lack of validity or enforceability of Debtor's Obligations or any agreement or
instrument relating thereto or any other circumstance which might otherwise
constitute a defense available to, or a discharge of, Debtor or the undersigned
and the undersigned hereby consents to and waives notice of any of the
foregoing. The undersigned further expressly waives (i) all diligence in
collection and any failure or delay by Lender in protection or perfection of
Lender's rights under the Loan or in or to any collateral securing any of
Debtor's Obligations, (ii) notice of acceptance by Lender of this Guaranty or of
the Loan, (iii) notice of advancement of any additional funds to or for the
benefit of Debtor, (iv) presentment, demand for payment, protest and notice of
protest, default, non-payment or partial payment by Debtor, (v) all other
notices and formalities to which Debtor and/or the undersigned might be
entitled, by statute or otherwise, (vi) any right of subrogation, reimbursement,
exoneration, contribution, indemnity or any other right that would result in
Guarantor being deemed a creditor of Debtor under the United States Bankruptcy
Code or any other law or any right to enforce any remedy which Lender now has or
may hereafter have against Debtor and any benefit of, and any right to
participate in, any security now or hereafter held by Lender, whether any of the
foregoing arise in equity, at law or by contract and (vii) any other action or
any other circumstance whatsoever which might constitute a defense to
enforcement of this Guaranty. This Guaranty shall continue to be effective or be
reinstated, as the case may be, if at any time any payment of any of the
Debtor's Obligations is rescinded or must otherwise be returned by Lender upon
the insolvency, bankruptcy or reorganization of Debtor or otherwise, all as
though such payment had not been made.

The undersigned further waives any right of setoff, recoupment or counterclaim
against Lender with respect to any claim or demand the undersigned may at any
time have against Debtor, or against any other person or concern liable for
Debtor's Obligations, and as further security to Lender, any and all debts or
liabilities


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now or hereafter owing to the undersigned by Debtor, and/or such other person or
concern, and any lien, security or collateral given to the undersigned in
connection therewith, are hereby subordinated to the claims and liens of, and
assigned to, Lender.

The obligations of the undersigned hereunder are and shall at all times be the
original, direct and primary obligations of the undersigned, as if the
undersigned were the Debtor under the Loan. Lender shall not in any event be
obligated to pursue or exhaust any rights or remedies against Debtor or others,
or resort to any security, prepayments or collateral, as a prerequisite to
enforcing this Guaranty against the undersigned. This Guaranty shall be binding
upon the undersigned and its, his or her respective heirs, personal
representatives, successors and assigns, and shall inure to the benefit of
Lender and its successors and assigns. All of the obligations and agreements of
the undersigned in this Guaranty are joint and several.

If the undersigned is a corporation, each signatory on behalf of such
corporation warrants that he or she has the authority to sign on behalf of such
corporation and by so signing, to bind said corporation hereunder. No
modification or waiver of any of the provisions of this Guaranty shall be
effective unless in writing and signed by the undersigned and an officer of
Lender. Guarantor, being a corporation with publicly held debt or equity, shall
furnish to Lender promptly upon their availability, copies of all financial
statements, reports, notices and proxy statements, if any, sent by Guarantor to
its public security holders, and all regular and periodic reports filed by
Guarantor with the principal securities exchange including without limitation
balance sheet, profit and loss statement and statement of cash flows, with said
fiscal year reports audited by a recognized firm of independent certified public
accountants reasonably satisfactory to Lender on which the securities of
Guarantor are listed, if any, or with the Securities and Exchange Commission,
including but not limited to 10-K and 10-Q reports. If any provision of this
Guaranty or the application thereof is hereafter held invalid or unenforceable,
the remainder of this Guaranty shall not be affected thereby, and to this end
the provisions of this Guaranty are declared severable.

Guarantor is not in default under any agreement, contract or judgment to which
Guarantor is a party and any period of cure has expired, in an amount of $5
million or more .

Guarantor has filed all required material tax returns and has paid all material
taxes to the extent they have become due other than those which are being
contested in good faith by appropriate proceedings and as to which appropriate
reserves are being maintained by Guarantor in accordance with GAAP and so long
as such proceedings operate during the pendency thereof to prevent the sale,
forfeiture, or loss of the Collateral, and Guarantor does not have any knowledge
of any actual or proposed deficiency or additional assessment in connection
therewith.

This Guaranty shall be governed in all respects by the laws of the State of
California and the undersigned hereby irrevocably consent to the jurisdiction of
the California State Courts and the United States Courts located in Los Angeles
County.

         Dated this __________ day of June, 1999.

Witness:                                    Guarantor:
-----------------------------------         The Doe Run Resources Corporation

By:  /s/ William W. Simms                   By: /s/ David Chaput
   --------------------------------            ---------------------------------
Printed Name:  William W. Simms             Printed Name:  David Chaput
               --------------------                        ---------------------

Title:  Cash and Financial Manager          Title:  Treasurer
      -----------------------------               ------------------------------


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