Document:

<PAGE>
                                                                    Exhibit 10.7

                                                                  EXECUTION COPY

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                                 LOAN AGREEMENT

                                      among

                       SOCIEDAD MINERA CERRO VERDE S.A.A.,
                                   as Borrower

                        EACH OF THE LENDERS NAMED HEREIN,

                                       and

                             CALYON NEW YORK BRANCH,
                             as Administrative Agent

                         Dated as of September 30, 2005

================================================================================

<PAGE>

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                            Page
                                                                            ----
<S>      <C>                                                                <C>
Section 1.  Definitions and Accounting Matters...........................     1
   1.01  Certain Defined Terms...........................................     1
   1.02  Other Definitions; Headings.....................................     4
   1.03  Reference to Master Participation Agreement.....................     4
   1.04  Interpretation..................................................     5

Section 2.  Loans, Promissory Notes and Prepayments......................     5
   2.01  Loans...........................................................     5
   2.02  Borrowings......................................................     5
   2.03  Agent and Other Fees............................................     6
   2.04  Commitment Fees.................................................     6
   2.05  Lending Offices.................................................     6
   2.06  Several Obligations; Remedies Independent.......................     6
   2.07  Promissory Notes................................................     6
   2.08  Voluntary Prepayments of Loans..................................     6
   2.09  Pro Rata Prepayments............................................     6
   2.10  Change in Commitments...........................................     7
   2.11  Mandatory Prepayments...........................................     7

Section 3.  Payments of Principal and Interest...........................     7
   3.01  Repayment of Loans..............................................     7
   3.02  Interest........................................................     8

Section 4.  Payments; Pro Rata Treatment; Computations; Etc..............     8
   4.01  Payments........................................................     8
   4.02  Pro Rata Treatment..............................................     9
   4.03  Computations....................................................     9
   4.04  Certain Notices.................................................     9
   4.05  Non-Receipt of Funds by the Administrative Agent................    10

Section 5.  Yield Protection, Etc........................................    11
   5.01  Additional Costs................................................    11
   5.02  Alternate Interest Rate.........................................    13
   5.03  Compensation....................................................    14
   5.04  Mitigation......................................................    15
   5.05  Applicable Lending Offices......................................    15
</TABLE>

                                      -i-

<PAGE>

<TABLE>
<S>      <C>                                                                <C>
Section 6.  Conditions Precedent.........................................    15
   6.01  Initial Loans...................................................    15
   6.02  Additional Conditions...........................................    15

Section 7.  Representations and Warranties...............................    15

Section 8.  Covenants....................................................    15

Section 9.  Events of Default; Remedies..................................    15
   9.01  Events of Default...............................................    15
   9.02  Remedies........................................................    16

Section 10. The Administrative Agent.....................................    16
   10.01 Appointment, Powers and Immunities..............................    16
   10.02 Reliance by Administrative Agent................................    17
   10.03 Defaults........................................................    17
   10.04 Indemnification.................................................    17
   10.05 Non-Reliance on Administrative Agent and Other Lenders..........    18
   10.06 Failure to Act..................................................    18
   10.07 Resignation or Removal of Administrative Agent..................    18
   10.08 Voting..........................................................    19
   10.09 Administrative Agent Notices....................................    19

Section 11. Miscellaneous................................................    19
   11.01 Waiver..........................................................    19
   11.02 Notices.........................................................    20
   11.03 Amendments, Etc.................................................    21
   11.04 Successors and Assigns..........................................    21
   11.05 Assignments and Participations..................................    22
   11.06 Survival/Reinstatement..........................................    22
   11.07 No Immunity.....................................................    23
   11.08 Counterparts....................................................    23
   11.09 GOVERNING LAW AND SUBMISSION TO JURISDICTION....................    23
   11.10 WAIVER OF JURY TRIAL............................................    23
   11.11 Judgment Currency...............................................    23
   11.12 Severability....................................................    23
   11.13 English Language................................................    23
</TABLE>

APPENDIX 1 - Notice of Borrowing

EXHIBIT A  - Form of Promissory Note
EXHIBIT B  - Amortization Schedule
EXHIBIT C  - Assignment and Acceptance Agreement

                                      -ii-

<PAGE>

          LOAN AGREEMENT dated as of September 30, 2005 among SOCIEDAD MINERA
CERRO VERDE S.A.A., a sociedad anonima abierta organized under the laws of Peru
(the "Borrower"); each of the Lenders that is a signatory hereto as a "Lender",
or each lender that may from time to time become a Lender, pursuant to Section
11.05(b) hereof, (each, a "Lender" and, collectively, the "Lenders"); and CALYON
NEW YORK BRANCH, as agent for the Lenders (in such capacity, the "Administrative
Agent").

          WHEREAS, On the date hereof, the Borrower, JBIC, the Lead JBIC
Arrangers, KfW, the Lenders and the Administrative Agent have entered into the
Master Participation Agreement (the "Master Participation Agreement"), which
sets forth various terms for the financing of the development of the Sulfide
Project;

          WHEREAS, for purposes of financing in part the development of the
Sulfide Project, the Borrower desires that the Lenders make certain loans to it,
and the Lenders wish to make certain loans to the Borrower, all on the terms and
conditions set forth herein and in the Master Participation Agreement.

          NOW THEREFORE, in consideration of the foregoing, the agreements
contained herein and in the Master Participation Agreement and for other good
and valid consideration, the receipt and adequacy of which are hereby expressly
acknowledged, the parties hereto agree as follows:

          Section 1. Definitions and Accounting Matters.

          1.01 Certain Defined Terms. Except as otherwise defined herein,
capitalized terms used herein (including the preamble and recital of this
Agreement) shall have the meanings assigned to such terms in the Master
Participation Agreement (including Schedule Z thereto). For purposes of this
Agreement, the following terms shall have the respective meanings set forth
below:

          "Additional Costs" has the meaning assigned thereto in Section
5.01(a).

          "Advance Date" has the meaning assigned thereto in Section 4.05.

          "Agreement" means this Loan Agreement.

          "Applicable Lending Office" means, for each Lender, the "Lending
Office" of such Lender (or of an affiliate of such Lender) designated on the
signature pages hereof or such other office of such Lender (or of an affiliate
of such Lender) as such Lender may from time to time designate pursuant to
Section 5.05 as the office by which its Loans are to be made and maintained.

          "Availability Period" means, collectively, the Tranche A Availability
Period and the Tranche B Availability Period.

          "Borrower" has the meaning assigned thereto in the first paragraph of
this Agreement.

                         Commercial Banks Loan Agreement

<PAGE>

                                       -2-

          "Borrowing" means Loans made on the same date and as to which a single
Interest Period is in effect pursuant to a Notice of Borrowing.

          "Commitment" means the aggregate of the Tranche A Commitment and the
Tranche B Commitment.

          "Default Interest Period" means each successive period (not in excess
of six months) as the Administrative Agent shall choose (with the consent of the
Majority Bank Lenders), during which any amount payable by the Borrower
hereunder is in default. The first such period shall commence as of the date on
which such amount in default becomes due, and each such succeeding period shall
commence immediately upon the expiry of the immediately preceding period;
provided, however, that in the absence of, or pending consent of the Majority
Bank Lenders, each Default Interest Period has a duration of one month.

          "Default Margin" means, in respect of any principal of any Loan or any
other amount under this Agreement (including interest on a Loan), a rate per
annum equal to 2%.

          "Eurocurrency Liabilities" has the meaning assigned thereto in
Regulation D.

          "Lenders" has the meaning assigned thereto in the first paragraph of
this Agreement.

          "LIBOR Rate" means, with respect to any Interest Period or Default
Interest Period for any Loan, the interest rate per annum for deposits in
Dollars, if any, for a period equal to the relevant interest period which
appears on page 3750 on the Moneyline Telerate Inc. (or such other page or pages
as shall replace that page or pages for the purpose of displaying offered rates
of leading banks for London interbank deposits in Dollars) at or about 11:00
a.m. London time on the second Eurodollar Business Day before and for value on
the first day of the Interest Period or Default Interest Period. If such rate
does not appear on page 3750 on the Moneyline Telerate Inc. or such other page
as shall replace that page for the purpose of displaying offered rates of
leading banks for London interbank deposits in Dollars, the LIBOR Rate shall be
the interest per annum equal to the average (rounded upward to the nearest fifth
decimal place, if such average is not such a decimal) of the interest rates per
annum (as provided to the Administrative Agent) at which deposits in Dollars are
offered by the principal office of each of the Reference Banks in London,
England to prime banks in the London interbank market at or about 11:00 a.m.
(London time) (or as soon thereafter as practicable) two Eurodollar Business
Days before the first day of the Interest Period or Default Interest Period in
an amount substantially equal to each such Reference Bank's Loan comprising part
of such borrowing to be outstanding during such interest period and for a period
equal to (or if there is no equal, then most comparable) such interest period.
The LIBOR Rate for any interest period for each Loan comprising part of the same
borrowing shall be determined by the Administrative Agent on the basis of
applicable rates furnished to and received by such agent from the Reference
Banks two Eurodollar Business Days before the first day of such interest period.
If any of the Reference Banks shall be unable or otherwise fails to provide a
rate for the purposes of determining LIBOR as hereinabove provided, then LIBOR
shall be determined on the basis of the rate or rates quoted by the remaining
Reference Banks.

                         Commercial Banks Loan Agreement

<PAGE>

                                      -3-

          "LIBOR Reserve Period" has the meaning assigned to that term in
Section 5.01(d).

          "Loans" means, collectively, the Tranche A Loans and the Tranche B
Loans provided to the Borrower pursuant to Section 2.01.

          "Majority Bank Lenders" means Lenders holding more than 50% of the sum
of (a) the aggregate amount of uncancelled and undrawn Commitments and (b) the
aggregate principal amount of outstanding Loans.

          "Margin" means (a) for the period from and including the date hereof
to but excluding the Completion Release Date, 1.20% per annum, (b) for the
period from and including the Completion Release Date to but excluding the third
anniversary of the Completion Release Date, 1.4% per annum, (c) for the period
from and including the third anniversary of the Completion Release Date to but
excluding the fifth anniversary of the Completion Release Date, 1.70% per annum,
(d) for the period from and including the fifth anniversary of the Completion
Release Date to but excluding the seventh anniversary of the Completion Release
Date, 2% per annum and (e) for the period from and including the seventh
anniversary of the Completion Release Date thereafter, 2.20% per annum.

          "Master Participation Agreement" has the meaning assigned thereto in
the recitals of this Agreement.

          "Participant" has the meaning assigned thereto in Section 11.05(c).

          "Reference Banks" means, collectively CALYON New York Branch, Mizuho
Corporate Bank Ltd., Scotia Capital and The Royal Bank of Scotland plc, or such
substitute banks designated as such by the Administrative Agent from time to
time to provide the quotations required for the determination of the LIBOR Rate
and being the principal London offices of each such bank.

          "Regulation D" means Regulation D of the Board of Governors of the
Federal Reserve System of the United States (or any successor), as the same may
be modified and supplemented and in effect from time to time.

          "Regulatory Change" means, with respect to any Lender, any change
after the date of this Agreement in any law or regulations or the adoption or
making after such date of any interpretation, directive or request applying to a
class of financial institutions including such Lender of or under any law or
regulations (whether or not having the force of law and whether or not failure
to comply therewith would be unlawful) by any court or governmental or monetary
authority charged with the interpretation or administration thereof.

          "Substitute Basis" has the meaning assigned thereto in Section 5.02.

          "Tranche A Availability Period" means the period from the date hereof
until the Tranche A Commitment Termination Date.

                         Commercial Banks Loan Agreement

<PAGE>

                                      -4-

          "Tranche A Commitment" means, for each Lender, the obligation of such
Lender to make Tranche A Loans to the Borrower in an aggregate principal amount
not to exceed the amount set forth opposite the name of such Lender in Appendix
A-1 of the Master Participation Agreement (as the same may be reduced at any
time or from time to time pursuant to Sections 2.01, 2.10 and 11.05 hereof and
Section 2.03 of the Master Participation Agreement or pursuant to a permitted
assignment) or, in the case of an assignee of a Tranche A Commitment, the amount
specified in the Assignment and Acceptance Agreement entered into by such
assignee.

          "Tranche A Commitment Termination Date" means the earlier of (i) the
Availability Period End Date and (ii) the date on which the aggregate amount of
the Tranche A Commitments of all Lenders is fully borrowed, terminated or
reduced to zero.

          "Tranche A Loans" has the meaning assigned thereto in Section 2.01.

          "Tranche B Availability Period" means the period from the date on
which the Tranche A Loans shall have been fully drawn until the Tranche B
Commitment Termination Date.

          "Tranche B Commitment" means, for each Lender, the obligation of such
Lender to make Tranche B Loans to the Borrower in an aggregate principal amount
not to exceed the amount set forth opposite the name of such Lender in Appendix
A-1 of the Master Participation Agreement (as the same may be reduced at any
time or from time to time pursuant to Sections 2.01, 2.10 and 11.05 hereof and
Section 2.03 of the Master Participation Agreement or pursuant to a permitted
assignment) or, in the case of an assignee of a Tranche B Commitment, the amount
specified in the Assignment and Acceptance Agreement entered into by such
assignee.

          "Tranche B Commitment Termination Date" means the earlier of (i) the
Availability Period End Date and (ii) the date on which the aggregate amount of
the Tranche B Commitments of all Lenders is fully borrowed, terminated or
reduced to zero.

          "Tranche B Loans" has the meaning assigned thereto in Section 2.01.

          1.02 Other Definitions; Headings. The table of contents to this
Agreement and section headings contained herein are for convenience of reference
only and shall not affect the construction hereof.

          1.03 Reference to Master Participation Agreement. This Agreement and
the Master Participation Agreement shall be viewed as, and shall constitute, one
agreement governing the terms and conditions of the Loans; provided that the
exercise of enforcement remedies shall be made solely pursuant to and in
accordance with the Master Participation Agreement and the Master Security
Agreement. In the event of conflict between this Agreement and the Master
Participation Agreement or the Master Security Agreement, the Master
Participation Agreement or the Master Security Agreement, as the case may be,
shall prevail.

                         Commercial Banks Loan Agreement

<PAGE>

                                      -5-

          1.04 Interpretation. Section 1.02 of the Master Participation
Agreement is hereby incorporated herein by reference as if fully set forth
herein.

          Section 2. Loans, Promissory Notes and Prepayments.

          2.01 Loans.

          (a) Subject to the terms and conditions of this Agreement and the
Master Participation Agreement, each Lender severally agrees to make loans to
the Borrower in Dollars from time to time during the Tranche A Availability
Period (the "Tranche A Loans") in an aggregate principal amount up to but not
exceeding the amount of the Tranche A Commitment of such Lender. If the full
amount of the Tranche A Commitment is not disbursed during the Tranche A
Availability Period, the amount of any undrawn portion thereof shall be
automatically reduced to zero as provided in Section 2.03 of the Master
Participation Agreement.

          (b) Subject to the terms and conditions of this Agreement and the
Master Participation Agreement, each Lender severally agrees to make loans to
the Borrower in Dollars from time to time during the Tranche B Availability
Period (the "Tranche B Loans") in an aggregate principal amount up to but not
exceeding the amount of the Tranche B Commitment of such Lender. If the full
amount of the Tranche B Commitment is not disbursed during the Tranche B
Availability Period, the amount of any undrawn portion thereof shall be
automatically reduced to zero as provided in Section 2.03 of the Master
Participation Agreement.

          (c) Any amounts borrowed and paid or prepaid in accordance with the
terms herein shall not be reborrowed by the Borrower.

          2.02 Borrowings. The Borrower shall give the Administrative Agent (who
shall promptly notify the Lenders) notice of each Borrowing hereunder (which
notice shall be copied to the Trustee and shall be irrevocable and effective
upon receipt) as provided in Section 4.04, such notice to be substantially in
the form of Appendix 1 to this Agreement. Except as to a Borrowing which
utilizes the unborrowed Tranche A Commitments or Tranche B Commitments, as the
case may be, in full, each Borrowing hereunder shall be in a minimum amount of
US$2,500,000 and, if greater, in an amount which is an integral multiple of
US$1,000,000.

          Not later than 10:00 a.m. New York time on the date specified in each
notice for borrowing hereunder, each Lender shall make available the aggregate
amount of the Loans to be made by it on such date (as determined in accordance
with Section 4.02) to the Administrative Agent, at account number
01-88179-3701-00 (Attn: Loan Settlement, Ref: Cerro Verde) maintained by the
Administrative Agent with CALYON New York Branch (ABA# 026-008-073) in
immediately available funds. The amount so received by the Administrative Agent
shall, subject to the terms and conditions of this Agreement and the Master
Participation Agreement, be made available to the Borrower by 11:00 a.m. New
York time on such date, by depositing such amount, in immediately available
funds, in the Onshore Dollars Account.

                         Commercial Banks Loan Agreement

<PAGE>

                                      -6-

          2.03 Agent and Other Fees. The Borrower shall pay to the
Administrative Agent, for its own account, the Administrative Agent's fee, and
to the Lenders (as Lead Arrangers) the upfront fees, each in the amounts set
forth in the fee letter dated July 28, 2005 between the Lenders and the Borrower
on the dates set forth in such fee letter.

          2.04 Commitment Fees. The Borrower shall pay to the Administrative
Agent for the account of each Lender a commitment fee on the daily average
unused amount of such Lender's Tranche A Commitment and Tranche B Commitment,
for the period from and including the date hereof to but excluding the final day
of the Tranche A Availability Period and the Tranche B Availability Period, as
the case may be, at a rate per annum equal to 0.375%. Accrued commitment fees
shall be payable quarterly in arrears on each Interest Payment Date, on each
date falling three calendar months after each Interest Payment Date and, in the
case of the last installment of commitment fees payable hereunder, on the last
day of the Tranche A Availability Period and the Tranche B Availability Period,
as the case may be.

          2.05 Lending Offices. The Loans made by each Lender shall be made and
maintained at such Lender's Applicable Lending Office.

          2.06 Several Obligations; Remedies Independent. The amounts payable by
the Borrower at any time hereunder and under the Promissory Notes to each Lender
shall be separate and independent obligations of the Borrower and each Lender
shall be entitled, in accordance with the Master Participation Agreement, to
protect and enforce its rights arising out of this Agreement and the Promissory
Notes held by it, and, except as otherwise provided in the Master Participation
Agreement, it shall not be necessary for any other Lender or the Administrative
Agent to consent to, or be joined as an additional party in, any proceedings for
such purposes.

          2.07 Promissory Notes. As additional evidence of the Borrower's
obligation to pay the principal of the Loans as provided herein, the Borrower
shall execute and deliver to the Administrative Agent on behalf of each Lender,
Promissory Notes issued by the Borrower, in substantially the form set forth in
Exhibit A hereto, with a dual column translation into Spanish to be included
therein, in accordance with Section 2.08 of the Master Participation Agreement.

          2.08 Voluntary Prepayments of Loans. The Borrower shall have the right
to prepay Loans, either in whole or in part, in accordance with Section 3.05 of
the Master Participation Agreement, at any time or from time to time. Each
prepayment of Loans under this Section 2.08 shall be accompanied by the
prepayment compensation (if any) required under Section 3.11 of the Master
Participation Agreement. Any prepayment made by the Borrower pursuant to
Sections 2.08, 2.09 and 2.11 shall be made together with all accrued but unpaid
interest on amounts prepaid and all other amounts (including any amounts due
pursuant to Section 5) then due from the Borrower hereunder. Partial prepayment
shall be applied to the Loans in accordance with Section 3.08 of the Master
Participation Agreement.

          2.09 Pro Rata Prepayments. The extent to which prepayments by the
Borrower to any Senior Lender in respect of the Senior Loan Obligations must be
a Pro Rata Payment shall be determined in accordance with Section 3.04 of the
Master Participation Agreement. A Lender may waive its right to receive any such
prepayment without prejudice to its right to receive any

                         Commercial Banks Loan Agreement

<PAGE>

                                      -7-

subsequent prepayment. Each prepayment of Loans shall be accompanied by the
prepayment compensation (if any) required under Section 3.11 of the Master
Participation Agreement and shall be applied in accordance with the Master
Participation Agreement. Amounts prepaid pursuant to this Section 2.09 may not
be reborrowed by the Borrower.

          2.10 Change in Commitments.

          (a) Commitments Generally. The Borrower shall have the right to
terminate or reduce the aggregate unused amount of the Commitment subject to and
in accordance with Section 2.03 of the Master Participation Agreement.

          (b) Tranche B Loan Commitments. On the date on which the Borrower
issues Peruvian Bonds under the Peruvian Bonds Program, the Borrower shall
reduce the aggregate unutilized amount of Tranche B Commitments outstanding on
such date in an amount equal to the lesser of: (i) the aggregate amount of the
Peruvian Bonds issuance and (ii) the aggregate unutilized amount of Tranche B
Commitments outstanding on such date. To the extent that the aggregate proceeds
of issuance of the Peruvian Bonds on such date exceeds the aggregate unutilized
amount of Tranche B Commitments outstanding on such date, the Borrower shall
prepay the Tranche B Loans outstanding (together with interest accrued and
payable thereon) in an amount equal to the difference between (x) the aggregate
proceeds of issuance of the Peruvian Bonds on such date and (y) the aggregate
unutilized amount of Tranche B Commitments outstanding on such date.

          (c) No Reinstatement. Any portion of the Commitments once terminated
or reduced may not be reinstated.

          2.11 Mandatory Prepayments.

          (a) Loans. The Borrower shall be obligated to prepay the Loans
pursuant to Section 3.06 of the Master Participation Agreement.

          (b) Peruvian Bonds Program. On the date on which the Borrower issues
Peruvian Bonds under the Peruvian Bonds Program, the Borrower shall prepay the
Tranche B Loans in the principal amount required under Section 2.10(b).

          Section 3. Payments of Principal and Interest.

          3.01 Repayment of Loans. The Borrower hereby promises to pay to the
Administrative Agent, for the account of the Lenders, the principal amount of
the Loans in consecutive semi-annual installments payable commencing on the
first Payment Date and on each subsequent Payment Date thereafter, each such
installment to be in an aggregate principal amount computed in accordance with
the Amortization Schedule set forth in Exhibit B (which Amortization Schedule
may be revised by the Administrative Agent from time to time to take into
account (a) prepayments of the Loans pursuant to the terms hereof and the Master
Participation Agreement and (b) the actual first Payment Date); provided,
however, that the

                         Commercial Banks Loan Agreement

<PAGE>

                                      -8-

amount of the final payment of principal of the Loans shall in any event be
equal to the remaining unpaid principal amount of the Loans.

          3.02 Interest.

          (a) The Borrower hereby promises to pay to the Administrative Agent,
for the account of each Lender, interest on the unpaid principal amount of the
Loan from such Lender for the period from and including the date of such Loan to
but excluding the date such Loan shall be paid in full, at a rate per annum
equal to, for each Interest Period, the LIBOR Rate for such Loan for such
Interest Period plus the applicable Margin.

          (b) The Borrower agrees that during the Continuance of any MPA Event
of Default under Section 9.01 of the Master Participation Agreement (other than
an MPA Event of Default under Section 9.01(a) of the Master Participation
Agreement relating to this Agreement), the interest rate per annum which the
Borrower is obligated to pay in respect of each Interest Period pursuant to
sub-Section (a) above shall be increased by adding to such interest rate the
Default Margin.

          (c) Accrued interest on each Loan shall be payable on each Interest
Payment Date and upon any prepayment of a Loan (on the prepaid amount). Promptly
after the determination of any interest rate provided for herein or any change
therein, the Administrative Agent shall give notice thereof to each of the
Lenders and the Borrower.

          (d) If any installment of principal of any Loan or any other amount
(including interest on a Loan) payable hereunder is not paid in full when due
(whether at the stated due date, by acceleration, by mandatory prepayment or
otherwise), the Borrower hereby agrees to pay from time to time upon demand
interest on the amount past due and unpaid for such period of time within each
related Default Interest Period during which such amount shall remain due and
unpaid, at a rate per annum equal to (i) in respect of principal, the Default
Margin plus the greater of (A) the rate of interest payable in respect of such
principal pursuant to Section 3.02(a) (or, if applicable, Section 5.02) in
effect immediately prior to such default in payment and (B) the sum of the LIBOR
Rate for such Default Interest Period plus the Margin and (ii) in respect of
such other amounts, the Default Margin plus the LIBOR Rate for such Default
Interest Period plus the Margin.

          Section 4. Payments; Pro Rata Treatment; Computations; Etc.

          4.01 Payments.

          (a) Except to the extent otherwise provided herein, all payments of
principal, interest and other amounts to be made by the Borrower under this
Agreement and the Promissory Notes (including fees and indemnities) shall be
made in Dollars, in immediately available funds, without deduction, set-off or
counterclaim, to the Administrative Agent for the account of the Lenders at
account number 01-88179-3701-00 (Attn: Loan Settlement, Ref: Cerro Verde)
maintained by the Administrative Agent with CALYON New York Branch
(ABA#026-008-073), not later than 11:00 a.m. New York time on the date on which
such payment shall become

                         Commercial Banks Loan Agreement

<PAGE>

                                      -9-

due (each such payment made after such time on such due date to be deemed to
have been made on the next succeeding Business Day).

          (b) Each payment received by the Administrative Agent under this
Agreement or any Promissory Note for the account of any Lender shall be paid by
the Administrative Agent promptly to such Lender, in immediately available
funds, for the account of such Lender's Applicable Lending Office for the Loan
or other obligation in respect of which such payment is made.

          (c) If the due date of any payment under this Agreement or any
Promissory Note would otherwise fall on a day that is not a Business Day, such
date shall be extended to the next succeeding Business Day, and interest shall
be payable for any principal so extended for the period of such extension;
provided, however, that if such next succeeding Business Day falls in the
following month, such date shall be the Business Day immediately preceding such
date.

          4.02 Pro Rata Treatment. Except to the extent otherwise provided
herein or in the Master Participation Agreement, the Loans shall be disbursed by
the Lenders pro rata in accordance with the maximum respective principal amounts
of each Lender's Commitment. The extent to which payments by the Borrower to any
Senior Facility Lender in respect of the Senior Loan Obligations must be a Pro
Rata Payment shall be determined in accordance with Section 3.04 of the Master
Participation Agreement.

          4.03 Computations. Interest on Loans and commitment fees shall be
computed on the basis of a year of 360 days and actual days elapsed (including
the first day but excluding the last day) occurring in the period for which such
interest and commitment fees are payable.

          4.04 Certain Notices.

          (a) Notices by the Borrower to the Administrative Agent of borrowings,
termination or reduction of Commitments and voluntary prepayments of Loans shall
be irrevocable and shall be effective only if received by the Administrative
Agent not later than 11:00 a.m. New York time on the number of days, as the case
may be, prior to the date of the relevant borrowing, termination or reduction of
Commitments and voluntary prepayments of Loans, as the case may be, specified
below:

<TABLE>
<CAPTION>
Type of Notice                        Required Prior Notice
--------------                        ---------------------
<S>                                   <C>
Borrowing of Loans;                   15 Business Days for Base Advances
Termination or Reduction of           and 10 New York Business Days for
Commitments under Section 2.10; and   Stand-by Advances
Mandatory Prepayments of Loans

Voluntary Prepayments of Loans        60 days
</TABLE>

          (b) If received later than 11:00 a.m. New York time on such date, such
notice shall be effective on the next succeeding Business Day unless the
Borrower is notified by the Administrative Agent that such notice shall be
effective on the original Business Day.

                         Commercial Banks Loan Agreement

<PAGE>

                                      -10-

          (c) Each notice of borrowing or voluntary prepayment shall specify (i)
the Tranche A Loans and/or Tranche B Loans to be borrowed or prepaid, (ii) the
aggregate amount (subject to Sections 2.02, 2.08 and 2.09) of each Tranche A
Loan and/or Tranche B Loan to be borrowed and (iii) the date of borrowing or
voluntary prepayment (which shall be a Business Day). Each such notice of
termination or reduction shall specify the amount of the Commitments to be
terminated or reduced. The Administrative Agent shall promptly notify the
Lenders of the contents of each such notice (and in any event by the Business
Day after the Administrative Agent's receipt thereof).

          4.05 Non-Receipt of Funds by the Administrative Agent.

          (a) Without limiting Section 2.07 of the Master Participation
Agreement, unless the Administrative Agent shall have been notified by a Lender
or the Borrower (the "Payor") prior to the date on which the Payor is to make
payment to the Administrative Agent of (in the case of a Lender) the proceeds of
a Loan to be made by such Lender hereunder or (in the case of the Borrower) a
payment to the Administrative Agent for account of one or more of the Lenders
hereunder (such payment being herein called the "Required Payment"), which
notice shall be effective upon receipt, that the Payor does not intend to make
the Required Payment to the Administrative Agent, the Administrative Agent may
assume that the Required Payment has been made and may, in reliance upon such
assumption (but shall not be required to), make the amount thereof available to
the intended recipient(s) on such date; and, if the Payor has not in fact made
the Required Payment to the Administrative Agent, the recipient(s) of such
payment shall, on demand, repay to the Administrative Agent the amount so made
available together with interest thereon in respect of each day during the
period commencing on the date (the "Advance Date") such amount was so made
available by the Administrative Agent until the date the Administrative Agent
recovers such amount at a rate per annum equal to that indicated by the
Administrative Agent in a notice to such recipient(s) as the Administrative
Agent's cost of funds for such period (determined by the Administrative Agent in
its reasonable discretion, which determination shall be conclusive) and, if such
recipient(s) shall fail promptly to make such payment, the Administrative Agent
shall be entitled to recover such amount, on demand, from the Payor, together
with interest as aforesaid.

          (b) If neither the recipient(s) nor the Payor shall return the
Required Payment to the Administrative Agent within three Business Days of the
Advance Date, then, retroactively to the Advance Date, the Payor and the
recipient(s) shall each be obligated to pay interest on the Required Payment as
follows:

               (i) if the Required Payment shall represent a payment to be made
     by the Borrower, as the case may be, to the Lenders, the Payor(s) and the
     recipient(s) shall each be obligated retroactively to the Advance Date to
     pay interest in respect of the Required Payment at the rate of interest
     provided for pursuant to Section 3.02 (and, in case the recipient(s) shall
     return the Required Payment to the Administrative Agent, without limiting
     the obligation of any such Payor(s) under Section 3.02 to pay interest to
     such recipient(s) in respect of the Required Payment); and

                         Commercial Banks Loan Agreement

<PAGE>

                                      -11-

               (ii) if the Required Payment shall represent proceeds of a Loan
     to be made by the Lenders to the Borrower, the Payor and the Borrower shall
     each be obligated retroactively to the Advance Date to pay interest in
     respect of the Required Payment at the rate of interest provided for such
     Required Payment pursuant to Section 3.02 (and, in case the Borrower shall
     return such Required Payment to the Administrative Agent, without limiting
     any claim the Borrower may have against the Payor in respect of the
     Required Payment).

          (c) In the event that the Payor and the recipient(s) both return the
Required Payment to the Administrative Agent together with interest thereon as
required hereby, the Administrative Agent shall promptly pay to the recipient(s)
such Required Payment together with such interest paid by the recipient(s).

          (d) The Administrative Agent shall promptly notify each Lender of any
receipt of notice by the Administrative Agent from the Borrower that the
Borrower does not intend to make the Required Payment to the Administrative
Agent for account of one or more of the Lenders.

          Section 5. Yield Protection, Etc.

          5.01 Additional Costs.

          (a) The Borrower shall pay directly to each Lender from time to time
such amounts as are necessary to compensate such Lender for any increase in
costs attributable to its making or maintaining of any Loans to the Borrower or
its obligation to make any Loans hereunder to the Borrower, or any reduction in
any amount receivable by such Lender hereunder in respect of any of such Loans
or such obligation (such increases in costs and reductions in amounts receivable
being herein called "Additional Costs"), in each case, from those costs and
amounts receivable existing on the date hereof, resulting from any Regulatory
Change that:

          (i) imposes or modifies any reserve, special deposit or similar
     requirements, including any application of the Regulation D requirement,
     relating to any extensions of credit or other assets of, or any deposits
     with or other liabilities of, such Lender (including any of such Loans or
     any deposits referred to in the definition of "LIBOR Rate" in Section
     1.01), or any commitment of such Lender (including the Commitment of such
     Lender hereunder); or

          (ii) imposes or any Lender or the London interbank market any other
     condition affecting this Agreement or Loans made by such Lender.

          (b) Without limiting the effect of the foregoing provisions of this
Section 5.01 (but without duplication), the Borrower shall pay directly to each
Lender from time to time on request such amounts as such Lender may determine in
good faith to be necessary to compensate such Lender (or, without duplication,
the bank holding company of which such Lender is a subsidiary) for any increase
in costs that it in good faith determines is attributable to the maintenance by
such Lender (or any Applicable Lending Office or such bank holding company),
pursuant to any law or regulation or any interpretation, directive, guideline or
request (whether or

                         Commercial Banks Loan Agreement

<PAGE>

                                      -12-

not having the force of law and whether or not failure to comply therewith would
be unlawful) of or by any court or governmental, monetary, fiscal or other
authority (i) following any Regulatory Change or (ii) implementing any
risk-based capital guideline or other requirement (whether or not having the
force of law and whether or not the failure to comply therewith would be
unlawful) issued after the date of this Agreement by any government or
governmental or supervisory authority implementing at the national level the
Basle Accord, of capital in respect of its Commitment or Loans (such
compensation to include, without limitation, an amount equal to any reduction of
the rate of return on assets or equity of such Lender (or any Applicable Lending
Office or such bank holding company) to a level below that which such Lender (or
any Applicable Lending Office or such bank holding company) could have achieved
but for such law, regulation, interpretation, directive, guideline or request).
For purposes of this Section 5.01(b), "Basle Accord" shall mean the proposals
for risk-based capital framework described by the Basle Committee on Banking
Regulations and Supervisory Practices in its paper entitled "International
Convergence of Capital Measurement and Capital Standards" dated July 1988, as
amended, modified and supplemented and in effect from time to time or any
replacement thereof.

          (c) Section 5.01 does not apply, and no Lender shall be entitled to
make any claim under Section 5.01, to the extent any Additional Cost is
attributable directly or indirectly to the application of, compliance with or
implementation of any part or "pillar" of the International Convergence of
Capital Measurement Standards: a Revised Framework, published by the Basle
Committee on Banking Supervision in June 2004 (as in effect on the date hereof),
or any implementation or interpretation thereof, whether by any law or
regulation, or otherwise, or to any change by a Lender from one method of
calculating capital adequacy to another, insofar as such Additional Costs are
directly or indirectly attributable to credit-related events or circumstances
that are specific to a Lender and not solely to general regulatory guidelines or
requirements imposed on the commercial banking sector generally.

          (d) Each Lender shall notify the Borrower of any event occurring after
the date of this Agreement entitling such Lender to compensation under clause
(a) or (b) of this Section 5.01 as promptly as practicable, but in any event,
within six months after such Lender obtains actual knowledge thereof; provided,
that if such Lender fails to give such notice within six months after it obtains
actual knowledge of such an event, such Lender shall, with respect to
compensation payable pursuant to this Section 5.01 in respect of any Additional
Costs resulting from such event, only be entitled to payment under this Section
5.01 for costs incurred from and after the date six months prior to the date
that such Lender does give such notice. Each Lender shall designate a different
Applicable Lending Office, if possible, for the Loans of such Lender affected by
such event if such designation will avoid the need for, or reduce the amount of,
such compensation and will not, in the sole opinion of such Lender, be
disadvantageous to such Lender, except that such Lender shall have no obligation
to designate an Applicable Lending Office located in the United States of
America. Each Lender shall furnish to the Borrower a certificate setting forth
in reasonable detail the basis and amount of each request by such Lender for
compensation under clause (a) or (b) of this Section 5.01. The payment of any
such amount by the Borrower shall not preclude the Borrower from contesting such
calculation.

                         Commercial Banks Loan Agreement

<PAGE>

                                      -13-

          (e) In the event that any Lender shall determine at any time that it
is required to maintain reserves in respect of Eurocurrency Liabilities during
any period during which the principal amount of any Loan is outstanding (each
such period, for such Lender, a "LIBOR Reserve Period"), but only in respect of
any period during which any reserve shall actually be maintained by such Lender
for the Loans as a result of a reserve requirement applicable to it under
Regulation D in connection with Eurocurrency Liabilities, then such Lender shall
promptly give notice to the Borrower and the Administrative Agent of such
determination, and the Borrower shall directly pay to such Lender additional
interest on the unpaid principal amount of such Loan during such LIBOR Reserve
Period at a rate per annum which shall, during each monthly period applicable to
such Loan, be the amount by which (i) the LIBOR Rate for such monthly period
divided (and rounded upward, if necessary, to the next whole multiple of 1/100
of 1%) by a percentage equal to 100% minus the then-stated maximum rate of all
reserve requirements (including, without limitation, any marginal, emergency,
supplemental, special or other reserves) applicable to such Lender in respect of
Eurocurrency Liabilities exceeds (ii) the LIBOR Rate for such monthly period.
Any Lender so requesting compensation shall furnish along with such notice a
certificate setting forth in reasonable detail the cost actually incurred to
maintain such reserves and the basis for the determination of such amount.
Additional interest payable pursuant to the immediately preceding sentence shall
be paid by the Borrower at the time that it is otherwise required to pay
interest in respect of such Loan or, if later demanded by any Lender, promptly
on the next Payment Date for any principal of the Loans after such demand. Each
Lender agrees that, if it gives notice to the Borrower and the Administrative
Agent of the existence of a LIBOR Reserve Period, it shall promptly notify the
Borrower and the Administrative Agent of any termination thereof, at which time
the Borrower shall cease to be obligated to pay additional interest to such
Lender pursuant to the first sentence of this paragraph until such time, if any,
as a subsequent LIBOR Reserve Period shall occur.

          (f) Any determination or allocation made by any Lender pursuant to
this Section 5.01 shall be made by such Lender in good faith and, absent error,
will be conclusive, so long as such determination is applied to the Borrower in
a non-discriminatory manner as compared to similarly situated borrowers.

          5.02 Alternate Interest Rate. Anything herein to the contrary
notwithstanding, if, on or prior to the determination of any LIBOR Rate for any
Interest Period or Default Interest Period:

          (a) the Administrative Agent determines, which determination shall be
     conclusive absent manifest error, that quotations of interest rates for the
     relevant deposits referred to in the definition of "LIBOR Rate" in Section
     1.01 hereof are not being provided in the relevant amounts or for the
     relevant maturities for purposes of determining rates of interest as
     provided herein; or

          (b) the Majority Bank Lenders notify the Administrative Agent that (i)
     the relevant rates of interest referred to in the definition of "LIBOR
     Rate" in Section 1.01 hereof upon which the rate of interest for such
     Interest Period or Default Interest Period is to be determined will not
     adequately reflect the cost to such Lenders of making or maintaining Loans,
     or maintaining any other amount hereunder not paid when due, for

                         Commercial Banks Loan Agreement

<PAGE>

                                      -14-

     such Interest Period or Default Interest Period or (ii) deposits in Dollars
     in the London interbank market are not available to Lenders in the ordinary
     course of business in sufficient amounts to make and/or maintain their
     Loans,

then the Administrative Agent shall notify the Borrower thereof and the
following provisions shall apply:

          (A) During the thirty-day period following the date of any such notice
     (the "Negotiation Period"), the Administrative Agent (on behalf of the
     Lenders) and the Borrower will negotiate in good faith for the purpose of
     agreeing upon an alternative, mutually acceptable basis (the "Substitute
     Basis") for determining the rate of interest to be applicable to Loans, and
     any other amounts hereunder not paid when due, from time to time and if, at
     the expiry of the Negotiation Period, the Administrative Agent (on behalf
     of the Lenders) and the Borrower have agreed upon a Substitute Basis and
     any required governmental approvals therefor have been obtained, the
     Substitute Basis shall take effect from such date (including such
     retroactive date) as the Administrative Agent (on behalf of the Lenders)
     and the Borrower may in such circumstance agree.

          (B) If at the expiry of the Negotiation Period, a Substitute Basis
     shall not have been agreed upon or any required governmental approvals
     therefor shall not have been obtained, the Administrative Agent (with the
     consent of the Majority Bank Lenders) shall notify the Borrower of the cost
     to the Lenders (as reasonably determined by them) of funding and
     maintaining the outstanding affected Loans, and any other amounts hereunder
     not paid when due for such Interest Period or Default Interest Period and
     the interest payable to the Lenders on Loans and such other amounts not
     paid when due to which such Interest Period or Default Interest Period
     applies shall be interest at a rate per annum equal to the cost of funding
     and maintaining such Loans or such other amounts as so notified by the
     Administrative Agent plus the applicable Margin plus, during any Interest
     Period or any Default Interest Period, upon the occurrence and during the
     Continuance of any MPA Event of Default under Section 9.01 of the Master
     Participation Agreement (other than any Event of Default under Section
     9.01(a) thereof relating to this Agreement), the Default Margin.

The procedures specified in (A) and (B) above shall apply to each relevant
period succeeding the first such period to which they were applied unless and
until the Administrative Agent notifies the Borrower that the condition referred
to in clause (a) of this Section 5.02 no longer exists or the Administrative
Agent (at the request of the Majority Bank Lenders) notifies the Borrower that
the condition referred to in clause (b) of this Section 5.02 no longer exists
(which notice the Lenders agree to give or cause to be given promptly following
the cessation of such condition), whereupon interest on Loans shall again be
determined in accordance with the provisions of Section 3.02, effective
commencing on the third Business Day after the date of such notice.

          5.03 Compensation. Upon request of the Administrative Agent on behalf
of any Lender, the Borrower shall pay to the Administrative Agent for the
account of such Lender such amount or amounts as shall be sufficient to
indemnify it for any Funding Losses in accordance with Section 3.11 of the
Master Participation Agreement.

                         Commercial Banks Loan Agreement

<PAGE>

                                      -15-

          5.04 Mitigation. If an event or circumstance occurs that would entitle
a Lender to exercise any of the rights or benefits afforded by this Section 5,
such Lender, promptly upon becoming aware of the same, shall take all steps as
may be reasonably available to eliminate or mitigate the effects of such event
or circumstance; provided, however, that such Lender shall not be under any
obligation to take any step that, in its sole discretion, would (a) result in
its incurring additional material costs or taxes or (b) otherwise be
disadvantageous to such Lender; provided, further, that the Borrower shall
reimburse any such Lender for all reasonable and documented costs and taxes
incurred pursuant to this Section 5.04.

          5.05 Applicable Lending Offices. A Lender may change its Applicable
Lending Office for any Loan by written notice to the Administrative Agent, the
Trustee and the Borrower and such notice shall be effective for purposes of this
Agreement as of the date specified therein.

          Section 6. Conditions Precedent.

          6.01 Initial Loans. The obligation of each Lender to make its initial
Loan hereunder is subject to Section 3.10 of the Master Participation Agreement
and the satisfaction (or waiver by each Lender) of any conditions set forth in
Section 5.01 of the Master Participation Agreement.

          6.02 Additional Conditions. The obligation of each Lender to make any
Loan hereunder (excluding its initial Tranche A Loan which is subject to
conditions described in Section 6.01 above) is subject to the satisfaction (or
waiver by it) of the following conditions:

          (a) Satisfaction of Common Conditions Precedent. The common conditions
     precedent set forth in Section 5.02 of the Master Participation Agreement
     shall have been satisfied (or waived as provided therein); and

          (b) Suspension. The obligation of any Senior Facility Lender shall not
     have been deemed to be suspended pursuant to Section 3.10 of the Master
     Participation Agreement.

          Section 7. Representations and Warranties. The Borrower has given
certain representations and warranties for the benefit of the Lenders in Article
VI of the Master Participation Agreement. The rights of the Lenders in respect
of such representations and warranties are set forth in the Master Participation
Agreement and the Master Security Agreement.

          Section 8. Covenants. The Borrower has given covenants and agreements
set forth in Article VII of the Master Participation Agreement. The rights of
the Lenders in respect of such covenants and agreement are set forth in the
Master Participation Agreement and the Master Security Agreement.

          Section 9. Events of Default; Remedies.

          9.01 Events of Default. Subject to Section 9.02, each of the MPA
Events of Default set forth in Section 9.01 of the Master Participation
Agreement is hereby incorporated by

                         Commercial Banks Loan Agreement

<PAGE>

                                      -16-

reference in this Agreement as if fully set forth herein, in accordance with
their terms, unless waived in accordance with the Master Participation
Agreement.

          9.02 Remedies. Upon the occurrence and Continuance of an MPA Event of
Default as provided in Section 9.01 hereof, the Lenders shall have each of the
rights and remedies provided in the Master Participation Agreement and the
Master Security Agreement exercisable only pursuant to and in accordance with
the terms thereof.

          Section 10. The Administrative Agent.

          10.01 Appointment, Powers and Immunities.

          (a) Each Lender hereby irrevocably appoints and authorizes the
Administrative Agent to act as its agent hereunder, with such rights,
authorities, discretions and powers as are specifically delegated to the
Administrative Agent by the terms of this Agreement, together with such other
powers as are reasonably incidental thereto, and each Lender authorizes and
instructs the Administrative Agent to execute and deliver each of the Master
Participation Agreement, the Completion Guarantee, the Transfer Restrictions
Agreement and any other Financing Document to which such Lender and/or the
Administrative Agent is a party and each such Lender agrees to be bound by the
terms and conditions of each such agreement as if it had executed and delivered
such agreement for and in its own name.

          (b) Each Lender hereby agrees and acknowledges that the Administrative
Agent shall act for and on behalf of the Lenders hereunder for purposes of each
of the Master Participation Agreement, the Completion Guarantee and the Transfer
Restrictions Agreement, and each Lender hereby authorizes such action by the
Administrative Agent on its behalf in accordance with its appointment hereunder.
Notwithstanding the foregoing, the Administrative Agent shall promptly upon
request of any Lender deliver any request, notice or communication permitted to
be given by any Senior Facility Lender under or pursuant to the Master
Participation Agreement, the Completion Guarantee and the Transfer Restrictions
Agreement.

          (c) The Administrative Agent (which term as used in this sentence and
in Section 10.05 shall include reference to its Affiliates and its Affiliates'
officers, directors, employees and agents) shall not: (i) have any duties or
responsibilities except those expressly set forth in this Agreement, or by
reason of this Agreement be a trustee for any Lender, (ii) be responsible to the
Lenders for any recitals, statements, representations or warranties contained in
this Agreement, or in any certificate or other document referred to or provided
for in, or received by any of them under, this Agreement, or for the value,
validity, effectiveness, genuineness, enforceability or sufficiency of this
Agreement, any Promissory Note or any other document referred to or provided for
herein or for any failure by the Borrower or any other Person to perform any of
its obligations hereunder or thereunder, (iii) be required to initiate or
conduct any litigation or collection proceedings hereunder or (iv) be
responsible for any action taken or omitted to be taken by it hereunder or under
any other document or instrument referred to or provided for herein or in
connection herewith, except for its own gross negligence or willful misconduct.

                         Commercial Banks Loan Agreement

<PAGE>

                                      -17-

          (d) The Administrative Agent may employ agents and attorneys-in-fact,
and the Administrative Agent shall not be responsible for the negligence or
misconduct of any such agents or attorneys-in-fact selected by it in good faith.
The Administrative Agent may deem and treat the payee of any Promissory Note as
the holder thereof for all purposes hereof unless and until a notice of the
assignment or transfer thereof shall have been filed with the Administrative
Agent.

          (e) Any bank serving as Administrative Agent hereunder shall have the
same rights and powers in its capacity as a Lender as any other Lender and may
exercise the same as though it were not the Administrative Agent, and such bank
and its Affiliates may accept deposits from, lend money to and generally engage
in any kind of business with the Borrower or Affiliate thereof as if it were not
the Administrative Agent hereunder.

          10.02 Reliance by Administrative Agent. The Administrative Agent shall
be entitled to rely upon, and shall not incur any liability for relying upon,
any certification, notice, request, consent, statement, instrument, document or
other communication (including any thereof by telephone, telecopy, telex,
telegram or cable) believed by it to be genuine and correct and to have been
signed or sent by or on behalf of the proper Person or Persons, and upon advice
and statements of legal counsel, independent accountants and other experts
selected by the Administrative Agent. As to any matters not expressly provided
for by this Agreement, the Administrative Agent shall in all cases be fully
protected in acting, or in refraining from acting, hereunder in accordance with
instructions given by the Majority Bank Lenders, and such instructions of the
Majority Bank Lenders and any action taken or failure to act pursuant thereto
shall be binding on all of the Lenders. The Administrative Agent shall not be
responsible for or have any duty to ascertain or inquire into (a) any statement,
warranty or representation made in or in connection with this Agreement, any
other Financing Document or the Sulfide Project, (b) the contents of any
certificate, report or other document delivered hereunder or in connection
herewith, (c) the performance or observance of any of the covenants, agreements
or other terms or conditions set forth herein, (d) the validity, enforceability,
effectiveness or genuineness of this Agreement or any other agreement,
instrument or document, or (e) the satisfaction of any condition set forth in
Section 6 or elsewhere herein, other than to confirm receipt of items required
to be delivered to the Administrative Agent.

          10.03 Defaults. The Administrative Agent shall not be deemed to have
knowledge or notice of the occurrence of an MPA Default (other than the
non-payment of principal of or interest on Loans or of commitment fees) unless
the Administrative Agent has received notice from a Lender or the Borrower
specifying such MPA Default and stating that such notice is a "Notice of
Default". In the event that the Administrative Agent receives such a notice of
the occurrence of any MPA Default, the Administrative Agent shall give prompt
notice thereof to the Lenders and the Borrower (and shall give each Lender
prompt notice of each such non-payment).

          10.04 Indemnification. The Lenders agree to indemnify the
Administrative Agent (to the extent not reimbursed under Section 12.21 of the
Master Participation Agreement, but without limiting the obligations of the
Borrower under said Section 12.21 of the Master Participation Agreement) ratably
in accordance with the aggregate principal amount of the Loans

                         Commercial Banks Loan Agreement

<PAGE>

                                      -18-

held by the Lenders (or, if no Loans are at the time outstanding, ratably in
accordance with their respective Commitments), for any and all liabilities,
obligations, losses, claims, damages, penalties, actions, judgments,
settlements, suits, costs, expenses or disbursements of any kind and nature
whatsoever that may be imposed on, incurred by or asserted against (including by
any Lender) the Administrative Agent arising out of or by reason of any
investigation in or in any way relating to or arising out of this Agreement or
any other documents contemplated by or referred to herein or the transactions
contemplated hereby (including, without limitation, the costs and expenses that
the Borrower is obligated to pay under Section 12.21 of the Master Participation
Agreement but excluding, unless an MPA Event of Default has occurred and is
continuing, normal administrative costs and expenses incident to the performance
of the Administrative Agent's agency duties hereunder) or the enforcement of any
of the terms hereof or of any such other documents; provided, however, that no
Lender shall be liable for any of the foregoing to the extent they arise from
the gross negligence or willful misconduct of the Administrative Agent.

          10.05 Non-Reliance on Administrative Agent and Other Lenders. Each
Lender agrees that it has, independently and without reliance on the
Administrative Agent or any other Lender, and based on such documents and
information as it has deemed appropriate, made its own credit analysis of the
Borrower and its respective Affiliates and its own decision to enter into this
Agreement and that it will, independently and without reliance upon the
Administrative Agent or any other Lender, and based on such documents and
information as it shall deem appropriate at the time, continue to make its own
analysis and decisions in taking or not taking action under this Agreement. The
Administrative Agent shall not be required to keep itself informed as to the
performance or observance by the Borrower of this Agreement or any other
document referred to or provided for herein or to inspect the properties or
books of the Borrower. Except for notices, reports and other documents and
information expressly required to be furnished to the Lenders by the
Administrative Agent hereunder (as to which the Administrative Agent only shall
have the duty to forward what it has received), the Administrative Agent shall
not have any duty or responsibility to provide any Lender with any credit or
other information concerning the affairs, financial condition or business of the
Borrower or any of its respective Affiliates that may come into its possession.

          10.06 Failure to Act. Except for action expressly required of the
Administrative Agent hereunder, the Administrative Agent shall in all cases be
fully justified in failing or refusing to act hereunder unless it shall receive
further assurances to its satisfaction from the Lenders of their indemnification
obligations under Section 10.04 against any and all liability and expense that
may be incurred by the Administrative Agent by reason of taking or continuing to
take any such action.

          10.07 Resignation or Removal of Administrative Agent. The
Administrative Agent, subject to the appointment of a successor as provided in
this Section 10.07, may resign at any time by notifying the Lenders and the
Borrower. The Administrative Agent may be removed as agent hereunder upon 30
days' notice by an instrument in writing signed by the Majority Bank Lenders and
the Borrower. Upon any such resignation or removal, the Majority Bank Lenders
shall have the right, with the approval of the Borrower not to be unreasonably
withheld, to appoint a successor Administrative Agent. No removal or resignation
of a Administrative Agent

                         Commercial Banks Loan Agreement

<PAGE>

                                      -19-

or appointment of a successor Administrative Agent shall be effective until (a)
the appointment of a successor is accepted and (b) solely in the case of a
removal all indemnity and compensation required under the Financing Documents
have been paid or provided for. If no successor shall have been so appointed by
Majority Bank Lenders and shall have accepted such appointment within 30 days
after the retiring Administrative Agent gives notice of its resignation, then
the retiring Administrative Agent may, on behalf of the Lenders, appoint a
successor Administrative Agent with the approval of the Borrower not to be
unreasonably withheld which shall be a bank with an office in New York, New York
or London, or an affiliate of any such bank. Upon the acceptance of its
appointment as the Administrative Agent hereunder by a successor Administrative
Agent, such successor Administrative Agent shall succeed to and become vested
with all the rights, powers, privileges and duties of the retiring
Administrative Agent and the retiring Administrative Agent shall be discharged
from its duties and obligations hereunder. The fees payable by the Borrower to a
successor Administrative Agent shall be the same as those payable to its
predecessor unless otherwise agreed between the Borrower and such successor.
After a Administrative Agent's resignation hereunder, the provisions of this
Section 10 shall continue in effect for its benefit in respect of any actions
taken or omitted to be taken by it while it was acting as the Administrative
Agent.

          10.08 Voting. Except as otherwise specified in the Master
Participation Agreement, in each instance that the Lenders are required to vote
hereunder, a vote shall be taken among the Lenders within the period of time
specified by the Administrative Agent.

          10.09 Administrative Agent Notices. The Administrative Agent agrees to
promptly furnish to each Lender a copy of each written communication (including
financial information and project reports) received by it from the Parent
Companies, the Borrower or the Trustee expressly relating to, and any amendment
or waiver of any of the provisions of, this Agreement, the Master Participation
Agreement, the Transfer Restrictions Agreement, the Security Documents, the
other Financing Documents, the Project Documents and the transactions
contemplated hereby and thereby, or from any Senior Lender pursuant to Section
10.02 of the Master Participation Agreement. In addition, the Administrative
Agent agrees to promptly advise each Lender of any material action taken, or any
action proposed by the Lenders to be taken that is not taken, by the Senior
Lenders at any meeting of Senior Lenders.

          Section 11. Miscellaneous.

          11.01 Waiver. Except as expressly provided herein, no failure on the
part of the Administrative Agent or any Lender to exercise and no delay in
exercising, and no course of dealing with respect to, any right, power or
privilege under this Agreement or any Promissory Note shall operate as a waiver
thereof, nor shall any single or partial exercise of any right, power or
privilege under this Agreement or any Promissory Note preclude any other or
further exercise thereof or the exercise of any other right, power or privilege.
The remedies provided herein are cumulative and not exclusive of any remedies
provided by law.

                         Commercial Banks Loan Agreement

<PAGE>

                                      -20-

          11.02 Notices.

          (a) Except as otherwise expressly provided herein, all notices and
other communications provided for hereunder shall be (i) in writing (including
telecopier) and (ii) telecopied or sent by overnight courier (if for inland
delivery) or international courier (if for overseas delivery) to a party hereto
at its address and contact number specified in the signature pages hereto, or at
such other address and contact number as is designated by such party in a
written notice to the other parties hereto.

          (b) All such notices and communications shall be effective (i) if sent
by telecopier, when sent (on receipt of written or oral confirmation of receipt)
and (ii) if sent by courier, (A) one day after deposit with an overnight courier
if for inland delivery and (B) three days after deposit with an international
courier if for overseas delivery. Notice of any address or facsimile number
change shall be effective only upon receipt.

          (c) The Borrower agrees that the Administrative Agent may make any
notices and communications received hereunder (the "Communications") available
to the Lenders in an electronic/soft medium by posting the Communications on
Intralinks or a substantially similar electronic transmission system (the
"Platform"). THE PLATFORM IS PROVIDED "AS IS" AND "AS AVAILABLE". THE AGENT
PARTIES (AS DEFINED BELOW) DO NOT WARRANT THE ACCURACY OR COMPLETENESS OF THE
COMMUNICATIONS, OR THE ADEQUACY OF THE PLATFORM AND EXPRESSLY DISCLAIM LIABILITY
FOR ERRORS OR OMISSIONS IN THE COMMUNICATIONS. NO WARRANTY OF ANY KIND, EXPRESS,
IMPLIED OR STATUTORY, INCLUDING, WITHOUT LIMITATION, ANY WARRANTY OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT OF THIRD
PARTY RIGHTS OR FREEDOM FROM VIRUSES OR OTHER CODE DEFECTS, IS MADE BY THE AGENT
PARTIES IN CONNECTION WITH THE COMMUNICATIONS OR THE PLATFORM. IN NO EVENT SHALL
THE ADMINISTRATIVE AGENT OR ANY OF ITS AFFILIATES OR ANY OF THEIR RESPECTIVE
OFFICERS, DIRECTORS, EMPLOYEES, AGENTS, ADVISORS OR REPRESENTATIVES
(COLLECTIVELY, THE "AGENT PARTIES") HAVE ANY LIABILITY TO ANY CREDIT PARTY, ANY
LENDER OR ANY OTHER PERSON OR ENTITY FOR DAMAGES OF ANY KIND, INCLUDING, WITHOUT
LIMITATION, DIRECT OR INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES,
LOSSES OR EXPENSES (WHETHER IN TORT, CONTRACT OR OTHERWISE) ARISING OUT OF SUCH
CREDIT PARTY'S OR THE ADMINISTRATIVE AGENT'S TRANSMISSION OF COMMUNICATIONS
THROUGH THE INTERNET, EXCEPT TO THE EXTENT THE LIABILITY OF ANY AGENT PARTY IS
FOUND IN A FINAL NON-APPEALABLE JUDGMENT BY A COURT OF COMPETENT JURISDICTION TO
HAVE RESULTED PRIMARILY FROM SUCH AGENT PARTY'S GROSS NEGLIGENCE OR WILLFUL
MISCONDUCT.

          (d) Each Lender agrees that notice to it (as provided in the next
sentence) specifying that the Communications have been posted to the Platform
shall constitute effective delivery of the Communications to such Lender for
purposes of the Financing Documents. Each Lender agrees (i) to provide to the
Administrative Agent in writing (including by electronic

                         Commercial Banks Loan Agreement

<PAGE>

                                      -21-

communication), promptly after the date of this Agreement, an e-mail address to
which the foregoing notice may be sent by electronic transmission and (ii) that
the foregoing notice may be sent to such e-mail address.

          (e) Nothing herein shall prejudice the right of the Administrative
Agent or any Lender to give any notice or other communication pursuant to any
Financing Document in any other manner specified in such Financing Document.

          11.03 Amendments, Etc.

          (a) Neither this Agreement nor any terms hereof may be amended,
supplemented or modified other than pursuant to a written instrument executed by
(i) Borrower, (ii) the Administrative Agent, acting in accordance with clause
(b) of this Section 11.03 and Section 10.01 of the Master Participation
Agreement and (iii) with respect to any amendment, supplement or modification
that modifies any provision of this Agreement in a manner that adversely affects
any rights of the Administrative Agent hereunder or enlarges its duties
hereunder, the Administrative Agent.

          (b) No amendment, modification, supplement or waiver of any provision
of this Agreement shall, unless by an instrument signed or consented to by all
of the Lenders: (i) increase, or extend the term of the Tranche A Commitments or
Tranche B Commitments, or extend the term or waive any requirement for the
reduction or termination of the Tranche A Commitments or Tranche B Commitments,
(ii) extend the date fixed for the payment of principal of or interest on any
Loan or any commitment or other fee hereunder or under the Promissory Notes,
(iii) reduce the amount of any such payment of principal, (iv) reduce the rate
at which interest is payable thereon or any commitment or other fee is payable
hereunder, or alter the basis for calculating any other obligations, (v) alter
the rights or obligations of the Borrower under Section 2.08, 2.09, 2.10 or
2.11, (vi) alter the terms of this Section 11.03 or Section 4.02, (vii) modify
the definition of the term "Majority Bank Lenders" or modify in any other manner
the number or percentage of the Lenders required to make any determinations or
waive any rights hereunder or to modify any provision hereof or (viii) waive any
of the conditions precedent set forth in Section 6.

          (c) No waiver by any party hereto of any of its rights, powers and
privileges under this Agreement shall be effective other than pursuant to a
written instrument executed by the Party waiving such right, power or privilege,
except that a waiver of rights, powers and privileges by the Senior Facility
Lenders can be executed by the Administrative Agent acting in accordance with
Section 10.01 of the Master Participation Agreement.

          (d) Any modification, supplement or waiver shall be for such period
and shall be subject to such conditions as shall be specified in the instrument
effecting the same and any such waiver shall be effective only in the specific
instance and for the purpose for which given.

          11.04 Successors and Assigns. This Agreement shall be binding upon and
inure to the benefit of the parties hereto and their respective successors and
permitted assigns.

                         Commercial Banks Loan Agreement

<PAGE>

                                      -22-

          11.05 Assignments and Participations.

          (a) The Borrower may not assign any of its rights or obligations
hereunder or under the Promissory Notes without the prior written consent of all
of the Lenders and the Administrative Agent (and any attempted assignment or
transfer by the Borrower without such consent shall be null and void).

          (b) Each of the Lenders may assign any and all of its rights and
obligations hereunder only pursuant to Section 12.13 of the Master Participation
Agreement. Upon execution and delivery by the assignee to the Borrower and the
Administrative Agent and the Administrative Agent of an assignment and
acceptance agreement substantially in the form of Exhibit C hereto (such
agreement, an "Assignment and Acceptance"), pursuant to which such assignee
agrees to become a "Lender" hereunder (if not already a Lender) having the
Commitment and Loans specified in such instrument, the assignee shall have, to
the extent of such assignment, the rights, obligations and benefits of a Lender
hereunder holding the Commitment and Loans (or portion(s) thereof) assigned to
it (in addition to the Commitment and Loans, if any, theretofore held by such
assignee) and the assigning Lender shall, to the extent of such assignment, be
released from the Commitment and Loans (or portion(s) thereof) so assigned (and,
in the case of an Assignment and Acceptance covering all of the assigning
Lender's rights and obligations under this Agreement, such Lender shall cease to
be a party hereto but shall continue to be entitled to, for periods during which
it held the Loans, the benefits of Sections 5.01 and 11.06 hereof and Sections
3.09 and 12.21 of the Master Participation Agreement).

          (c) Each Lender may sell or agree to sell to one or more commercial
banks or lending institutions (a "Participant") a participation in all or any
part of its Loans, its Promissory Notes or in its Commitments; provided that no
Participant shall have any rights or benefits under this Agreement, any
Promissory Note or any other Financing Documents. All amounts payable by the
Borrower to any Lender under Section 5 in respect of Loans held by it, and its
Commitment, shall be determined as if such Lender had not sold or agreed to sell
any participations in such Loans and Commitment, and as if such Lender were
funding each of such Loan and Commitment in the same way that it is funding the
portion of such Loan and Commitment in which no participations have been sold.

          (d) A Lender or the Administrative Agent, as the case may be, may
furnish any information concerning the Borrower in the possession of such Lender
or the Administrative Agent from time to time to assignees and Participants
(including prospective assignees and Participants) subject to the
confidentiality provisions set forth in Section 12.10 of the Master
Participation Agreement.

          11.06 Survival/Reinstatement. The obligations of the Borrower under
Section 5 and the obligations of the Lenders under Section 10.04 shall survive
the repayment of the Loans and the termination of the Commitments. This
Agreement shall continue to be effective or be reinstated, as the case may be,
if at any time payment and performance of the Borrower's obligations hereunder,
or any part thereof, is, pursuant to applicable law, rescinded or reduced in
amount, or must otherwise be restored or returned by the Administrative Agent or
any Lender. In the event that any payment or any part thereof is so rescinded,
reduced, restored or returned,

                         Commercial Banks Loan Agreement

<PAGE>

                                      -23-

such obligations shall be reinstated and deemed reduced only by such amount paid
and not so rescinded, restored or returned.

          11.07 No Immunity. To the extent that any party hereto has or
hereafter may acquire any immunity from jurisdiction of any court or from any
process (whether through service of notice, attachment prior to judgment,
attachment in aid of execution, execution, sovereign immunity or otherwise) with
respect to itself or its property, it irrevocably waives such immunity, to the
fullest extent permitted by law, in respect of its obligations under this
Agreement and the Promissory Notes.

          11.08 Counterparts. This Agreement may be executed in any number of
counterparts, all of which taken together shall constitute one and the same
instrument and any of the parties hereto may execute this Agreement by signing
any such counterpart.

          11.09 GOVERNING LAW AND SUBMISSION TO JURISDICTION. THIS AGREEMENT
SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF
NEW YORK. THE PROVISIONS OF SECTION 12.16 OF THE MASTER PARTICIPATION AGREEMENT
SHALL BE DEEMED INCORPORATED HEREIN MUTATIS MUTANDIS. THE BORROWER CONFIRMS ITS
APPOINTMENT OF CT CORPORATION AS AGENT FOR SERVICE OF PROCESS, PURSUANT TO
SECTION 12.16(B) OF THE MASTER PARTICIPATION AGREEMENT.

          11.10 WAIVER OF JURY TRIAL. EACH OF THE BORROWER AND THE LENDERS
HEREBY WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY AND ALL
RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING DIRECTLY OR INDIRECTLY ARISING
OUT OF OR RELATING TO THIS AGREEMENT, THE NOTES OR THE TRANSACTIONS CONTEMPLATED
HEREBY WHETHER BASED ON CONTRACT, TORT OR OTHER THEORY.

          11.11 Judgment Currency. This is an international loan transaction in
which the specification of Dollars and payment in New York, New York, United
States of America is of the essence, and Dollars shall be the currency of
account in all events. The provisions of Section 12.06 of the Master
Participation Agreement shall be deemed incorporated herein in its entirety.

          11.12 Severability. Any provision of this Agreement which is
prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction,
be ineffective to the extent of such prohibition or unenforceability without
invalidating the remaining provisions hereof, and any such prohibition or
unenforceability in any jurisdiction shall not invalidate or render
unenforceable such provision in any other jurisdiction.

          11.13 English Language. This Agreement is made in the English
language. Any translation of this Agreement shall have no legal validity.

                         Commercial Banks Loan Agreement

<PAGE>

                                      -24-

            [The remainder of this page is intentionally left blank.]

                         Commercial Banks Loan Agreement

<PAGE>

                                       S-1

          IN WITNESS WHEREOF, the parties hereto have caused this Agreement to
be duly executed and delivered as of the day and year first above written.

                               The Borrower

                               SOCIEDAD MINERA CERRO VERDE S.A.A.

                               By: /s/ Cristian Moran
                                   ---------------------------------------------
                               Name: Cristian Moran
                               Title: Attorney in Fact

                               Address for: Sociedad Minera Cerro
                               Notices      Verde S.A.A.
                                            c/o Asiento Minero Cerro Verde
                                            Uchumayo (Arequipa/Peru),
                                            Casilla Postal #299
                                            Shipping: Av. Alfonso Ugarte #304
                                            Cercado, Arequipa, Republic of Peru
                               Attention: General Manager
                               Fax No.: (054) 283-376
                               Telephone No.: (054) 283-363

                               With a copy to: PDC, at
                                               Phelps Dodge Tower
                                               1 North Central Avenue
                                               Phoenix, Arizona 85004
                                               U.S.A
                               Attention: Treasurer
                               Fax No: (602) 366-8150
                               Telephone No: (602) 366-8100

                         Commercial Banks Loan Agreement

<PAGE>

                                       S-2

                                The Administrative Agent

                                CALYON NEW YORK BRANCH,
                                     as Administrative Agent

                                By: /s/ Ted Vandermel
                                    --------------------------------------------
                                Name: Ted Vandermel
                                Title: Director

                                By: /s/ Samuel Sherman
                                    --------------------------------------------
                                Name: Samuel Sherman
                                Title: Director

                                Address for notices: CALYON New York Branch
                                                     1301 Avenue of the Americas
                                                     New York, New York 10019

                                Attention: Ted Vandermel
                                Fax No.: 212.261.3421
                                Telephone No.: 212.261.7888

                         Commercial Banks Loan Agreement

<PAGE>

                                       S-3

                                The Lenders

Commitment

Tranche A: US$22,500,000        CALYON NEW YORK BRANCH,
Tranche B: US$22,500,000           as Lender

                                By: /s/ Georges Romano
                                    --------------------------------------------
                                Name: Georges Romano
                                Title: Managing Director

                                By: /s/ Samuel Sherman
                                    --------------------------------------------
                                Name: Samuel Sherman
                                Title: Director

                                Lending Office: New York Branch

                                Address for notices: CALYON New York Branch
                                                     1301 Avenue of the Americas
                                                     New York, New York 10019

                                Attention: Ted Vandermel
                                Fax No.: 212.261.3421
                                Telephone No.: 212.261.7888

                         Commercial Banks Loan Agreement

<PAGE>

                                       S-4

Commitment

Tranche A: US$22,500,000        MIZUHO CORPORATE BANK, LTD.,
Tranche B: US$22,500,000           as Lender

                                By: /s/ Masatoshi Abe
                                    --------------------------------------------
                                Name: Masatoshi Abe
                                Title: Senior Vice President

                                Lending Office: New York Branch

                                Address for Notices: 1251 Avenue of the Americas
                                                     New York, New York 10020

                                Attention: Paul Nicholas
                                Fax No.: 212.282.3618
                                Telephone No.: 212.282.4864

                         Commercial Banks Loan Agreement

<PAGE>

                                       S-5

Commitment

Tranche A: US$22,500,000          THE BANK OF NOVA SCOTIA,
Tranche B: US$22,500,000             as Lender

                                  By: /s/ Michael K. Eddy
                                      ------------------------------------------
                                  Name: Michael K. Eddy
                                  Title: Director-Mining

                                  By: /s/ Alexander Mihailovich
                                      ------------------------------------------
                                  Name: Alexander Mihailovich
                                  Title: Associate

                                  Lending Office: Toronto

                                  Address for Notices: Scotia Capital
                                                       40 King Street West,
                                                       62nd Floor P.O. Box 4085,
                                                       Station A Corporate
                                                       Banking - Mining Toronto,
                                                       Ontario, Canada M5W 2X6

                                  Attention: Michael K. Eddy
                                             Alexander Mihailovich
                                  Fax No.: 416.866.2009
                                  Telephone No.: 416.866.7186/0006

                         Commercial Banks Loan Agreement

<PAGE>

                                       S-6

Commitment

Tranche A: US$22,500,000     THE ROYAL BANK OF SCOTLAND PLC,
Tranche B: US$22,500,000        as Lender

                             By: /s/ Gregor Hamilton
                                 -----------------------------------------------
                             Name: Gregor Hamilton
                             Title: Associate Director

                             Lending Office: The Royal Bank of Scotland plc
                                             Structured Finance, Level 5
                                             135 Bishopsgate London EC2M 3UR
                                             United Kingdom

                             Address for notices: The Royal Bank of Scotland
                                                  plc Structured Finance,
                                                  Level 5 135 Bishopsgate London
                                                  EC2M 3UR United Kingdom

                             Attention: Graham Boreham
                             Fax No.: ++44 20 7375 8762
                             Telephone No.: ++44 20 7648 3978

                         Commercial Banks Loan Agreement

<PAGE>

                                                                      Appendix 1
                                                               to Loan Agreement

                           FORM OF NOTICE OF BORROWING

                                        [Date](1)

TO: [____________________] (the "Administrative Agent")

FROM: Sociedad Minera Cerro Verde S.A.A. (the "Borrower")

RE: Notice of Borrowing pursuant to Section 2.02 of the Commercial Banks Loan
    Agreement dated as of September 30, 2005 between the Borrower, CALYON New
    York Branch, as Administrative Agent and the Lenders party thereto (the
    "Loan Agreement")

          The Borrower hereby requests disbursement under the Loan Agreement to
the Onshore Dollars Account under the Master Security Agreement on ________,
20__ (the "Disbursement Date") in an aggregate amount equal to [US$ ___________
as a Tranche A Loan] and/or [US$ ________ as a Tranche B Loan].(2)

          Disburse to: [name of bank in New York, account number]

          The Borrower hereby represents and warrants to the Lenders and the
Administrative Agent as of the date hereof that:

          1. The requested disbursement date is a Business Day falling on or
     before the [Tranche A Commitment Termination Date] and/or [the Tranche B
     Commitment Termination Date].(3)

          2. The requested disbursement is pro rata with disbursements requested
     under the Senior Loan Documents and is calculated in accordance with
     Section [_______] of the Master Participation Agreement.

          3. The disbursements requested hereby have been or are scheduled to be
     utilized in accordance with Section 7.04 of the Master Participation
     Agreement.

          4. The disbursements of Senior Loans made to date (if any) have been
     or are being utilized for purposes of the Sulfide Project in accordance
     with Section 7.04 of the Master Participation Agreement.

----------
(1)  [To be dated no later than 15 Business Days before the date for the Loan to
     which this Notice of Borrowing relates.]

(2)  [To be inserted as applicable.]

(3)  [To be inserted as applicable.]

                  Appendix 1 to Commercial Banks Loan Agreement

<PAGE>

                                       -2-

          5. No MPA Default or MPA Event of Default has occurred and is
     Continuing.

          6. The conditions contained in [Section 5.01 [initial disbursement
     only] and] Section 5.02 of the Master Participation Agreement (4) and
     [Section 6.01 [initial disbursement only] and] Section 6.02 of the
     Commercial Banks Loan Agreement have been satisfied (or are expected to be
     satisfied on the date of disbursement, as applicable).

          The Borrower agrees that, if prior to its receipt of the disbursement
requested hereby it determines that any matter certified by it herein will not
be true and correct as of the time of such disbursement, it will promptly so
notify the Administrative Agent. Except to the extent set forth in any such
notice, each matter certified by the Borrower herein shall be deemed once again
to be certified as true and correct as of the time of such disbursement as if
then made.

          All defined terms used herein and not defined herein have the meanings
assigned to them in the Loan Agreement.

                                        SOCIEDAD MINERA CERRO VERDE S.A.A.

                                        By:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Title:
                                               ---------------------------------

----------
(4)  [To be inserted solely in connection with the initial disbursement of
     Loans.]

                  Appendix 1 to Commercial Banks Loan Agreement

<PAGE>

                                                                       Exhibit A
                                                               to Loan Agreement

                       [FORM OF PROMISSORY NOTE (PAGARE)]

                              PAGARE NO NEGOCIABLE

Place and date of issuance: Lima Peru, ____________
Amount US$ ____________

FOR VALUE RECEIVED, the undersigned, Sociedad Minera Cerro Verde, S.A.A. (the
"Borrower"), a sociedad anonima abierta listed on the Lima Stock Exchange and
duly incorporated under the laws of the Republic of Peru, registered with the
Public Registry of Companies of Lima, under File No. ____________, and whose
principal office is at ____________, Republic of Peru, by this non negotiable
(no negociable) promissory note ("pagare") (the "Promissory Note"), except as
permitted in Section 12.13 (b) of the MPA, unconditionally promises to pay to
the order of ____________ (the "Holder"), against presentment of this note, the
sum of ____________ dollars of the United States of America (US$ ____________)
(the "Principal Amount"), payable on the dates set forth in the following
payment schedule (each date, a "Payment Date") and in the amounts indicated next
to the applicable Payment Date, provided that the principal amount to be paid to
the Holder on a Payment Date shall not exceed the principal amount hereof
outstanding immediately prior to such Payment Date.

<TABLE>
<CAPTION>
                       PRINCIPAL AMOUNT TO BE
    PAYMENT DATE               REPAID
    ------------       ----------------------
<S>                    <C>
First Payment Date          ____________

6th month after the         ____________
First Payment Date

12th month after the        ____________
First Payment Date

18th month after the        ____________
First Payment Date

24th month after the        ____________
First Payment Date

30th month after the        ____________
First Payment Date

36th month after the        ____________
First Payment Date

42nd month after the        ____________
First Payment Date

48th month after the        ____________
First Payment Date

54th month after the        ____________
First Payment Date

60th month after the        ____________
First Payment Date

66th month after the        ____________
First Payment Date

72nd month after the        ____________
First Payment Date

78th month after the        ____________
First Payment Date

84th month after the        ____________
First Payment Date

90th month after the        ____________
First Payment Date
</TABLE>

                  Exhibit A to Commercial Banks Loan Agreement

<PAGE>

                                       -2-

          The Borrower also promises to pay to the Holder interest on the
outstanding and unpaid principal amount of this Promissory Note, from the date
hereof until the last Payment Date, at an annual rate of the Base Rate plus the
Applicable Margin (the "Interest Rate"), such interest to accrue semiannually on
the outstanding principal amount during the Interest Period. Interest shall be
payable in arrears on each Interest Payment Date. All computations of interest
shall be made on the basis of a year of 360 days and actual days elapsed
(including the first day but excluding the last day) occurring in the period for
which such interest are payable.

          If any payment to be made hereunder is due on a day which is not a
Business Day, such payment shall be made on the immediately succeeding Business
Day.

          If the principal amount of this Promissory Note is not paid in full
when due, then, without prejudice to any other rights or remedies of the Holder,
such principal amount remaining unpaid shall carry default interest for such
period of time within each related Default Interest Period during which such
amount shall remain due and unpaid at an annual rate equal to the Principal
Default Rate. If any other amount payable hereunder is not paid in full when
due, then, without prejudice to any other rights or remedies of the Holder, such
amount remaining unpaid shall carry default interest for such period of time
within each related Default Interest Period during which such amount shall
remain due and unpaid at an annual rate equal to the Other Amounts Default Rate.

          The Borrower may prepay on any Payment Date upon at least 60 days'
prior notice, all or part of the outstanding principal amount hereof, so long
as, in connection with a voluntary partial prepayment, the aggregate amount of
any such voluntary partial prepayment equals at least ____________(1) dollars of
the United States of America (US$____________).

          Borrower shall reimburse to the Holder its funding losses or expenses
(if any) related to such prepayment, if Borrower elects to voluntarily prepay
all or part of the outstanding principal amount hereof on a date other that an
Interest Payment Date or a Payment Date, as the case may be. No premium or
penalty shall be payable in connection with other prepayments.

          Each prepayment of the outstanding principal amount hereof shall
(unless such prepayment repays in full such outstanding principal amount) be
applied to prepay ratably each outstanding installment of principal hereof
remaining to be paid as of the date of such prepayment.

          For purposes of this Promissory Note, the following terms shall have
the following meanings:

          "Administrative Agent" means CALYON New York Branch in its capacity of
administrative agent for the Holder according to the MPA.

----------
(1)  Insert pro rata amount of the minimum prepayment amount applicable to the
     Advance(s) evidenced by the Promissory Note.

                  Exhibit A to Commercial Banks Loan Agreement

<PAGE>

                                       -3-

          "Applicable Margin" means [1.20% per annum](2).

          "Base Rate" means, with respect to any Interest Period or Default
Interest Period, the interest rate per annum for deposits in dollars of the
United States of America, if any, for a period equal to the relevant interest
period which appears on page 3750 on the Moneyline Telerate Inc. (or such other
page or pages as shall replace that page or pages for the purpose of displaying
offered rates of leading banks for London interbank deposits in dollars) at or
about 11:00 a.m. London time on the second Eurodollar Business Day before and
for value on the first day of the Interest Period or Default Interest Period. If
such rate does not appear on page 3750 on the Moneyline Telerate Inc. or such
other page as shall replace that page for the purpose of displaying offered
rates of leading banks for London interbank deposits in Dollars, the Base Rate
shall be the interest per annum equal to the average (rounded upward to the
nearest fifth decimal place, if such average is not such a decimal) of the
interest rates per annum (as provided to the Administrative Agent) at which
deposits in dollars of the United States are offered by the principal office of
each of the Reference Banks in London, England to prime banks in the London
interbank market at or about 11:00 a.m. (London time) (or as soon thereafter as
practicable) two Eurodollar Business Days before the first day of the Interest
Period or Default Interest Period in an amount substantially equal to each such
Reference Bank's Loan comprising part of such borrowing to be outstanding during
such interest period and for a period equal to (or if there is no equal, then
most comparable) such interest period. The Base Rate for any interest period
shall be determined by the Administrative Agent on the basis of applicable rates
furnished to and received by such agent from the Reference Banks two Business
Days before the first day of such interest period. If any of the Reference Banks
shall be unable or otherwise fails to provide a rate for the purposes of
determining the Base Rate as hereinabove provided, then the Base Rate shall be
determined on the basis of the rate or rates quoted by the remaining Reference
Banks.

          "Business Day" means a day on which banks are generally open for
business in New York, New York, United States, Tokyo, Japan, Frankfurt am Main,
Germany, London, England and Lima, Peru.

          "Collateral Agent" means Citibank del Peru S.A. in its capacity of
onshore collateral agent for the Holder according to the MSA.

          "Commercial Production Start-up Date" means the date as of which the
Borrower, in its judgment, has achieved start of commercial production as
notified by the Borrower to the Administrative Agent.

          "Concentrate" means the copper concentrate to be produced by Borrower
pursuant to the Sulfide Project.

          "Default Interest Period" means each successive period (not in excess
of six months) as the Administrative Agent shall choose (with the consent of the
Majority Bank

----------
(2)  On the closing date include the first applicable margin. On the Payment
     Date immediately following the Completion Release Date, the pagare shall be
     substituted to include the complete "Margin" language.

                  Exhibit A to Commercial Banks Loan Agreement

<PAGE>

                                       -4-

Lenders), during which any amount payable by the Borrower hereunder is in
default. The first such period shall commence as of the date on which such
amount in default becomes due, and each such succeeding period shall commence
immediately upon the expiry of the immediately preceding period; provided,
however, that in the absence of, or pending consent of the Majority Bank
Lenders, each Default Interest Period has a duration of one month.

          "Eurodollar Business Day" means any day on which banks are generally
open for business in London, England.

          "First Payment Date" means the earlier of (i) the March 20 or the
September 20 next occurring after the Commercial Production Start-up Date, and
(ii) March 20, 2008.

          "Government Rule" means any statute, law, regulation, ordinance, rule,
judgment, decree, injunction, order, writ, decision, directive, environmental
guideline, policy, restriction or rule of common law, requirement of, or other
mandatory governmental restriction or any similar form of decision of or
determination by, any Governmental Authority, and authoritative interpretations
thereof, whether now or hereafter in effect, applicable from time to time to the
relevant person, property or transaction.

          "Governmental Authority" means any national, state, county, city,
town, village, municipal or other local governmental department, commission,
board, bureau, agency, authority or instrumentality of any nation that affects
or may affect the transactions contemplated hereby or any political subdivision
thereof, and any person exercising executive, legislative, judicial, regulatory
or administrative functions of or pertaining to any of the foregoing entities,
including, without limitation, all commissions, boards, bureaus, arbitrators and
arbitration panels, and any authority or other person controlled by any of the
foregoing.

          "Interest Payment Date" means, prior to the First Payment Date, each
September 20 and March 20 and, starting on the First Payment Date, each Payment
Date.

          "Interest Period" means any of the following periods:

               (i) on or prior to the First Payment Date, each period commencing
     on an Interest Payment Date (or with respect to the first Interest Period
     on the date hereof) and ending on the day immediately preceding the next
     succeeding Interest Payment Date (including the first day and the last day
     of such period); and

               (ii) thereafter, each period commencing on a Payment Date and
     ending on the day immediately preceding the next succeeding Payment Date
     (including the first day and the last day of such period).

          "Loan Agreement" means the Loan Agreement dated as of September 30,
2005 among the Borrower, CALYON NEW YORK BRANCH, MIZUHO CORPORATE BANK, LTD.,
THE BANK OF NOVA SCOTIA, and THE ROYAL BANK OF SCOTLAND PLC.

          "MPA" means the Master Participation Agreement dated as of September
30, 2005 entered into among the Borrower, Japan Bank For International
Cooperation, Sumitomo

                  Exhibit A to Commercial Banks Loan Agreement

<PAGE>

                                       -5-

Mitsui Banking Corporation, The Bank of Tokyo-Mitsubishi, Ltd., KfW, CALYON New
York Branch, The Royal Bank of Scotland plc, The Bank of Nova Scotia, and Mizuho
Corporate Bank, Ltd.

          "MSA" means the Master Security Agreement dated as of September 30,
2005 entered into among the Borrower, Japan Bank For International Cooperation,
Sumitomo Mitsui Banking Corporation, The Bank of Tokyo-Mitsubishi, Ltd., KfW,
CALYON New York Branch, The Royal Bank of Scotland plc, The Bank of Nova Scotia,
Mizuho Corporate Bank, Ltd., Citibank, N.A., and Citibank del Peru S.A.

          "Other Amounts Default Rate" means the applicable Interest Rate
(including the Applicable Margin) plus 2% per annum.

          "Peruvian Income Tax Act" means the Legislative Decree 774 of December
31, 1993, as amended.

          "Principal Default Rate" means 2% per annum plus the greater of (i)
the Interest Rate (including the Applicable Margin) in effect immediately prior
to the date in which the respective principal amount became due and was not
paid, and (ii) the Base Rate for such Default Interest Period plus the
Applicable Margin.

          "Reference Banks" means, collectively CALYON New York Branch, Mizuho
Corporate Bank Ltd., Scotia Capital and The Royal Bank of Scotland plc, or such
substitute banks designated as such by CALYON New York Branch from time to time
to provide the quotations required for the determination of the Base Rate and
being the principal London offices of each such bank.

          "Sulfide Project" means the Borrower's development of a primary
sulfide portion of the ore body beneath the oxide portion of the ore body
currently in production at its Cerro Verde copper mine, located in the Districts
of Uchumayo and Yarabamba, Province of Arequipa, Peru.

          "Taxes" means any present and future taxes, levies, imposts, duties,
deductions, withholdings, fees, liabilities and similar charges.

          All payments by the Borrower of principal and interest hereunder shall
be made in dollars of the United States of America, in immediately available
funds, without deduction, set-off or counterclaim, to CALYON New York Branch for
the account of the Holder at account number ____________, favour ____________
maintained by CALYON, New York Branch (SWIFT code ____________) with
____________ (SWIFT code [________]), in New York, New York, not later than
11:00 a.m. New York time on the date on which such payment shall become due
(each such payment made after such time on such due date to be deemed to have
been made on the next succeeding Eurodollar Business Day).

          Any and all payments made by or on account of the Borrower in respect
of any obligation hereunder shall be made free and clear of, and without
deduction or withholding for or on account of, any and all present or future
Taxes (excluding (i) Taxes imposed on or measured

                  Exhibit A to Commercial Banks Loan Agreement

<PAGE>

                                       -6-

by the net income, profits, or capital of the Holder by the jurisdiction under
the laws of which the Holder was incorporated or organized, (ii) Taxes which
would not have been imposed on the Holder but for a change by the Holder of its
lending office, (iii) Taxes which would not have been imposed on a Holder but
for the transfer by the Holder of an interest herein or (iv) Taxes which would
not have been imposed on a Holder but for such Holder's having a place of
business in the jurisdiction imposing the Tax (other than a place of business
arising from the transaction contemplated hereby or from having executed,
delivered, performed its obligations or received a payment hereunder, or
enforced its rights hereunder)), Taxes described in the immediately preceding
clauses (i) through (iv) being referred to herein as the "Excluded Taxes" and
Taxes other than the Excluded Taxes being referred to herein as "Indemnified
Taxes", now or hereafter imposed, levied, collected, withheld or assessed by any
Governmental Authority of the Republic of Peru, unless such deduction or
withholding is required by an applicable Government Rule, in which case the
following paragraph shall apply.

          If the Borrower shall be required by law to deduct any Indemnified
Taxes now or hereafter imposed, levied or collected, withheld or assessed by any
Governmental Authority of the Republic of Peru from or in respect of any sum
payable hereunder, the Borrower shall, at its option, either (i) pay to the
Holder in respect of which such deduction or withholding is required to be made,
such additional amount (the "Additional Tax Amount") as may be necessary so that
after all required deductions and withholdings (including, without limitation,
deductions and withholdings applicable to additional sums payable under this
paragraph), the Holder receives on the due date thereof an amount equal to the
sum it would have received, had no such deduction or withholding been made, or
(ii) assume the payment of the Indemnified Tax and pay directly the full amount
to the tax administration when due in accordance with Article 47 of the Peruvian
Income Tax Act, so that the amount paid to the Holder equals the amount it would
have received if the Borrower had not been required by law to deduct such
Indemnified Tax.

          The Borrower agrees to pay or reimburse upon demand in like manner and
funds, any and all documented costs and expenses of the Holder hereof or of the
Collateral Agent with respect to the enforcement of this Promissory Note.

          The Borrower hereby irrevocably submits to the non-exclusive
jurisdiction of the Courts of Downtown Lima (Lima-Cercado) and of any Federal or
State court located in the Borough of Manhattan, The City of New York, as the
Holder hereof may elect for any proceeding arising out of or relating to this
Promissory Note. The Borrower waives, to the fullest extent it may effectively
do so, the defense of an inconvenient forum to the maintenance of such action or
proceeding.

          The Parties further agree that, without prejudice to the law of the
State of New York governing the substantive obligations contained in the Loan
Agreement, which has originated this Promissory Note, all procedural matters or
formalities applicable to this Promissory Note to be recognized as such shall be
governed by and construed in accordance with Peruvian law.

          This Promissory Note is issued in Spanish and English. The Parties
agree that the applicable version of this Promissory Note will be (i) the
Spanish version in case the jurisdiction

                  Exhibit A to Commercial Banks Loan Agreement

<PAGE>

                                       -7-

of the Courts of Downtown Lima (Lima-Cercado) is the jurisdiction elected by the
Holder, or be (ii) the English version in case the jurisdiction of any Federal
or State court located in the Borough of Manhattan, The City of New York is the
jurisdiction elected by the Holder. In case of discrepancies between the Spanish
and English versions (i) the Spanish version shall prevail when the Courts of
Downtown Lima (Lima-Cercado) or other Spanish speaking jurisdiction is the
jurisdiction elected by the Holder, and (ii) the English version shall prevail
when the Federal or State court located in the Borough of Manhattan, The City of
New York or any other non-Spanish speaking jurisdiction is the jurisdiction
elected by the Holder.

Lima, ____________

By: Sociedad Minera Cerro Verde, S.A.A.
Taxpayer Registry No.: 20170072465
Name of authorized officer: ____________
Identification Card No ____________
Power register in Entry No. ____________ of the Public Registry

                  Exhibit A to Commercial Banks Loan Agreement

<PAGE>

                                                                       EXHIBIT B

                     AMORTIZATION SCHEDULE

<TABLE>
<CAPTION>
              % of aggregate amount of all
Repayment   Advances made by the Lenders to
 Number                be repaid
---------   -------------------------------
<S>         <C>
     1                    6.25
     2                    6.25
     3                    6.25
     4                    6.25
     5                    6.25
     6                    6.25
     7                    6.25
     8                    6.25
     9                    6.25
    10                    6.25
    11                    6.25
    12                    6.25
    13                    6.25
    14                    6.25
    15                    6.25
    16                    6.25
</TABLE>

                  Exhibit B to Commercial Banks Loan Agreement

<PAGE>

                                                                       EXHIBIT C

                       ASSIGNMENT AND ACCEPTANCE AGREEMENT

          Reference is made to the Loan Agreement dated as of September 30, 2005
(as the same may be amended, supplemented or otherwise modified and in effect
from time to time, the "Loan Agreement"), among Sociedad Minera Cerro Verde
S.A.A., as Borrower, each of the Lenders named therein and [__________], as
Administrative Agent for the Lenders. Capitalized terms used but not defined
herein shall have the meanings assigned to them in the Loan Agreement.

          1. [__________] (the "Assignor") hereby sells and assigns to
[___________] (the "Assignee") without recourse to the Assignor, and the
Assignee hereby purchases and assumes from the Assignor without recourse to the
Assignor, effective as of the date set forth in Schedule 1 attached hereto (the
"Assignment Date"), the interests set forth on Schedule 1 hereto (the "Assigned
Interest") in the Assignor's rights and obligations under the Loan Agreement,
including, without limitation, the interests in the Commitment of the Assignor
on the Assignment Date and the Loans owing to the Assignor which are outstanding
on the Assignment Date as listed in Schedule 1 hereto, but excluding accrued
interest and fees to and excluding the Assignment Date. The assignment executed
hereby is made pursuant to and in accordance with Section 11.05(b) of the
Commercial Banks Loan Agreement. From and after the execution and delivery by
the Assignee to the Trustee and the Administrative Agent of this Assignment and
Acceptance Agreement, (a) the Assignee shall be a party to and be bound by the
provisions of the Loan Agreement, the Master Participation Agreement and each
other Financing Document the Assignor was party to and, to the extent of the
Assigned Interest, have the rights, obligations and benefits of a Lender
thereunder holding the Commitment and Loans (or portion(s) thereof) set forth on
Schedule 1 hereto and (b) the Assignor shall, to the extent of the Assigned
Interest, be released from the Commitment and Loans (or portion(s) thereof) so
assigned.

          2. The Assignor (a) represents and warrants that it is the legal and
beneficial owner of the interest being assigned by it hereunder and that such
interest is free and clear of any adverse claim, (b) makes no representation or
warranty and assumes no responsibility with respect to any statements,
warranties or representations made in or in connection with the Master
Participation Agreement, the Loan Agreement, the other Financing Documents or
the execution, legality, validity, enforceability, genuineness, sufficiency or
value of the Master Participation Agreement, the Loan Agreement, the other
Financing Documents or any other instrument or document furnished pursuant
thereto and (c) makes no representation or warranty and assumes no
responsibility with respect to the financial condition of the Borrower or the
performance or observance by the Borrower of any of their obligations under the
Master Participation Agreement, the Senior Loan Documents, the other Financing
Documents or the Project Documents or any other instrument or document furnished
pursuant thereto.

          3. The Assignee (a) represents and warrants that it is legally
authorized to enter into this Assignment and Acceptance, (b) confirms that it
has received a copy of the Master Participation Agreement, the Senior Loan
Documents, the other Financing Documents and such other documents and
information as it has deemed appropriate to make its own credit analysis

                  Exhibit C to Commercial Banks Loan Agreement

<PAGE>

                                       -2-

and decision to enter into this Assignment and Acceptance, (c) agrees that it
will, independently and without reliance upon the Trustee, the Administrative
Agent, the Assignor or any other Lender and based on such documents and
information as it shall deem appropriate at the time, continue to make its own
credit decisions in taking or not taking action under the Senior Loan Documents,
the Master Participation Agreement and the other Financing Documents, (d)
appoints and authorizes the Administrative Agent and the Administrative Agent,
respectively, to take such action as agent (in their respective capacities as
Administrative Agent under the Master Participation Agreement and Administrative
Agent under the Commercial Banks Loan Agreement, respectively), on its behalf
and to exercise such powers and discretion under the Master Participation
Agreement, the Commercial Banks Loan Agreement and each other Financing Document
as are delegated to the Administrative Agent and the Administrative Agent,
respectively, by the terms thereof, together with such powers as are incidental
thereto, (e) agrees that it will be bound by the provisions of, and will perform
in accordance with their terms all of the obligations which by the terms of the
Master Participation Agreement, the Commercial Banks Loan Agreement, the
Promissory Notes and the other Financing Documents are required to be performed
by it as a Lender and (f) specifies as its lending offices (and address for
notices) the offices set forth beneath its name on the signature pages hereof.

          From and after the Assignment Date, the Trustee and the Administrative
Agent, as applicable, shall make all payments under the Financing Documents in
respect of the interest assigned hereby (including, without limitation, all
payments of principal, interest or distributions) to the Assignee. The Assignor
and Assignee shall make all appropriate adjustments in payments under the
Financing Documents for periods prior to the Assignment Date directly between
themselves.

          THIS ASSIGNMENT AND ACCEPTANCE SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

                  Exhibit C to Commercial Banks Loan Agreement

<PAGE>

                                       -3-

          IN WITNESS WHEREOF, the parties hereto have caused this Assignment and
Acceptance to be executed by their respective officers thereunto duly
authorized, as of the date first above written.

                                       [NAME OF ASSIGNOR]

                                       By:
                                           -------------------------------------
                                       Name:
                                             -----------------------------------
                                       Title:
                                              ----------------------------------

                                       [NAME OF ASSIGNEE]

                                       By:
                                           -------------------------------------
                                       Name:
                                             -----------------------------------
                                       Title:
                                              ----------------------------------

                                       Lending Office (and address for notices):

                                       [Address]

Acknowledged this ______ day of
___________________, ____

[_____________________________],
    as Administrative Agent

By:
    --------------------------------
Name:
      ------------------------------
Title:
       -----------------------------

                  Exhibit C to Commercial Banks Loan Agreement

<PAGE>

                                       -4-

                                   Schedule 1
                                       to
                            Assignment and Acceptance
                             Dated ___________, ____

Date of Assignment: _____________

Legal Name of Assignor: ____________________________

Legal Name of Assignee: ____________________________

Assignee's Address for Notices: ________________________________________________

Effective Date of Assignment ("Assignment Date")(1): ________________

Amount of Assigned Tranche A Interest: ________________

Assigned Tranche A Commitment: ________________
Assigned Tranche A Loans outstanding as of the Assignment Date: ________________

Assignor's Total Tranche A Commitment and Tranche A Loans Outstanding as of the
Assignment Date: ________________

Assignee's Total Tranche A Commitment and Tranche A Loans Outstanding as of the
Assignment Date: ________________

Amount of Assigned Tranche B Interest: ________________

Assigned Tranche B Commitment: ________________
Assigned Tranche B Loans outstanding as of the Assignment Date: ________________

Assignor's Total Tranche B Commitment and Tranche B Loans Outstanding as of the
Assignment Date: ________________

Assignee's Total Tranche B Commitment and Tranche B Loans Outstanding as of the
Assignment Date: ________________

----------
(1)  [Must be at least five Business Days after execution hereof by all required
     parties.]

                  Exhibit C to Commercial Banks Loan Agreement<PAGE>
                                                                    Exhibit 10.8

                                                                  EXECUTION COPY

================================================================================

                            PARENT COMPANY GUARANTEE

                                     between

                            PHELPS DODGE CORPORATION

                                  as Guarantor

                                       and

                       SOCIEDAD MINERA CERRO VERDE S.A.A.

                               as Guaranteed Party

                         Dated as of September 30, 2005

================================================================================

<PAGE>

                                Table of Contents

<TABLE>
<CAPTION>
                                                                            Page
                                                                            ----
<S>                                                                         <C>
ARTICLE I DEFINITIONS AND INTERPRETATION.................................     1
   Section 1.01 Definitions..............................................     1
   Section 1.02 Interpretation...........................................     2

ARTICLE II GUARANTEE.....................................................     2
   Section 2.01 Guarantee of Obligor's Obligations.......................     2
   Section 2.02 Effectiveness and Term...................................     4
   Section 2.03 Payments.................................................     4

ARTICLE III CONSENT TO ASSIGNMENT........................................     4
   Section 3.01 Guaranteed Party May Assign to the Offshore
                Collateral Agent.........................................     4
   Section 3.02 Notice of Lenders' Reliance..............................     4
   Section 3.03 Offshore Collateral Agent to Receive Notice of Breach
                and Termination..........................................     5

ARTICLE IV REPRESENTATIONS AND WARRANTIES................................     5
   Section 4.01 Representations and Warranties of Guarantor..............     5

ARTICLE V CONSENT TO SUIT AND JURISDICTION...............................     6
   Section 5.01 Consent to Suit and Jurisdiction.........................     6
   Section 5.02 Guarantor's Agent for Service of Process.................     6

ARTICLE VI MISCELLANEOUS.................................................     6
   Section 6.01 Notices..................................................     6
   Section 6.02 Successors and Assigns...................................     7
   Section 6.03 Waiver of set-off........................................     7
   Section 6.04 Confidentiality..........................................     8
   Section 6.05 Execution in Counterparts................................     8
   Section 6.06 Amendments...............................................     8
   Section 6.07 Effectiveness............................................     8
   Section 6.08 No Trial by Jury.........................................     8
   Section 6.09 Severability.............................................     8
   Section 6.10 GOVERNING LAW............................................     8
</TABLE>

                                       i

<PAGE>

                            PARENT COMPANY GUARANTEE

          This PARENT COMPANY GUARANTEE ("Guarantee"), dated as of September 30,
2005, is made and entered into by Phelps Dodge Corporation, a company organized
under the laws of the State of New York ("Guarantor"), to and for the benefit of
Sociedad Minera Cerro Verde S.A.A., a sociedad anonima abierta, listed on the
Lima Stock Exchange and organized under the laws of Peru ("Guaranteed Party").

                                     WHEREAS

     A. The Guaranteed Party owns the Cerro Verde copper mine, including a
copper leaching and solution extraction/electrowinning (SX/EW) operation,
located in the District of Uchumayo and Yarabamba, Province of Arequipa, Peru
(the "Mine");

     B. On June 1, 2005, the Guaranteed Party and Minera Phelps Dodge del Peru
S.A.C., a Peruvian sociedad anonima abierta, (the "Operator") have entered into
an Operator's Agreement pursuant to which the Operator provides management
services for the operation of the Mine and certain other services relating
thereto (the "Operator's Agreement");

     C. On the date hereof, the Guaranteed Party, Japan Bank for International
Cooperation, Sumitomo Mitsui Banking Corporation, The Bank of Tokyo-Mitsubishi,
Ltd., KfW, Calyon New York Branch, The Royal Bank of Scotland plc, The Bank of
Nova Scotia and Mizuho Corporate Bank Ltd. have entered into a Master
Participation Agreement (the "Master Participation Agreement" or "MPA") which
sets forth various terms for the financing of the development of a primary
sulfide portion of the ore body beneath the oxide portion of the ore body
currently in production at the Mine (the "Sulfide Project"); and

     D. Guarantor, in consideration of the financing of the development of the
Sulfide Project by the Senior Lenders, has agreed to enter into this Guarantee
to guarantee the obligations of the Operator under the Operator's Agreement.

NOW, THEREFORE, in consideration of the mutual agreements herein contained and
other good and valuable consideration, the receipt and sufficiency of which is
hereby acknowledged, and in reliance upon the representations and warranties of
the Guarantor set forth herein, the parties hereto (the "Parties"), intending to
be legally bound hereby, agree as follows:

                                    ARTICLE I
                         DEFINITIONS AND INTERPRETATION

Section 1.01 Definitions. Unless the context shall otherwise require, or unless
otherwise defined herein, capitalized terms used herein shall have the meanings
assigned to them in Schedule Z to the Master Security Agreement dated as of
September 30, 2005 among Sociedad Minera Cerro Verde S.A.A., Japan Bank for
International Cooperation, Sumitomo Mitsui Banking Corporation, The Bank of
Tokyo-Mitsubishi, Ltd., KfW, Calyon New York Branch, The Royal Bank of Scotland
plc, The Bank of Nova Scotia, Mizuho Corporate Bank, Ltd., Citibank,

<PAGE>

N.A., and Citibank del Peru (as amended from time to time, the "Master Security
Agreement" or "MSA").

Section 1.02 Interpretation. In this Guarantee, except to the extent that the
context otherwise requires:

          (a) the Table of Contents and Section headings are for convenience of
reference only and shall not affect the interpretation of this Guarantee;

          (b) unless otherwise specified, references to Articles, Sections,
clauses and Appendices are references to Articles, Sections and clauses of, and
Appendices to, this Guarantee;

          (c) references to any document or agreement, including this Guarantee,
shall be deemed to include references to such document or agreement as amended,
supplemented or replaced and in effect from time to time in accordance with its
terms and subject to compliance with the requirements set forth herein and
therein;

          (d) references to any party to this Guarantee or any other document or
agreement or to any other Person shall include its successors and permitted
assigns;

          (e) when used in this Guarantee, the words "including", "includes" and
"include" shall be deemed to be followed in each instance by the words "without
limitation";

          (f) when used in this Guarantee, the words "herein", "hereby",
"hereunder", "hereof", "hereto", "hereinbefore", and "hereinafter", and words of
similar import, shall refer to this Guarantee in its entirety and not to any
particular section, subsection, paragraph, clause or other subdivision, exhibit,
schedule or appendix of this Guarantee; and

          (g) when used herein, the singular shall include the plural, the
plural shall include the singular and the use of any gender shall include all
genders, unless the context requires otherwise.

                                   ARTICLE II
                                    GUARANTEE

Section 2.01 Guarantee of Obligor's Obligations.

          (a) Guarantor hereby irrevocably, unconditionally and absolutely
guarantees to the Guaranteed Party the punctual and full performance and payment
(as primary and joint obligor and not merely as surety) of each and every
obligation of the Operator and of any directly or indirectly wholly-owned
affiliate of Guarantor that succeeds to the obligations of Operator under the
Operator's Agreement, a "Guaranteed Successor" and, collectively with the
Operator, an "Obligor", each such obligation a "Guaranteed Obligation" and,
collectively, the "Guaranteed Obligations", in each case whether now existing or
hereafter existing or due or to become due, so long as such Guaranteed
Obligations are not performed or paid by the Obligor when and as

                                        2

<PAGE>

performance or payment, as the case may be, of the same shall become due,
whether at maturity, upon acceleration or otherwise, pursuant to the terms of
the Operator's Agreement.

          (b) Guarantor agrees that its obligations under this Section 2.01
shall be unconditional and irrevocable, irrespective of (i) the invalidity or
unenforceability of the Guaranteed Obligations, (ii) the absence of any action
to enforce the Guaranteed Obligations against the Obligor, (iii) any amendment,
waiver or consent by the Guaranteed Party with respect to any provision of the
Operator's Agreement, (iv) the recovery of any judgment against the Obligor or
any action to enforce the same, (v) the insolvency or bankruptcy of the Obligor
or (vi) any other circumstance which might otherwise constitute a legal or
equitable discharge or defense of a guarantor or surety.

          (c) Guarantor hereby waives (i) diligence, presentment, demand of
payment, protest, notice and all demands whatsoever with respect to any
Guaranteed Obligation, (ii) filing of claims with a court in the event of
insolvency or bankruptcy of the Obligor and (iii) any right to require a
proceeding first against the Obligor or against any other Person under any
guarantee of, or security for, any Guaranteed Obligation.

          (d) Guarantor agrees that its obligations under this Article II with
respect to any Guaranteed Obligation will not be discharged except by complete
performance or payment by Obligor or by Guarantor of such Guaranteed Obligation.
In the event that any payment made by Obligor to the Guaranteed Party in respect
of any Guaranteed Obligation is rescinded or must otherwise be returned for any
reason whatsoever, such payment shall be treated as a Guaranteed Obligation and
Guarantor shall remain liable for such Guaranteed Obligation to the extent
provided herein as if such payment had not been made and,

               (x) if Guarantor's obligations under this Parent Company
     Guarantee have been terminated in accordance with this Guarantee, such
     obligations shall be reinstated to the extent necessary for the Guarantor
     to comply with the foregoing provisions of this sentence,

               (y) Guarantor agrees that it will pay or reimburse the Guaranteed
     Party within 30 days of written request for all reasonable and documented
     costs and expenses (including reasonable and documented fees and
     disbursements of counsel) incurred by the Guaranteed Party in connection
     with the rescission or restoration of this Parent Company Guarantee,
     including any such costs and expenses incurred in defending against any
     claim alleging that any payment constituted a preference, fraudulent
     transfer or similar payment under any bankruptcy, insolvency or similar
     law.

          (e) Guarantor agrees that the Guaranteed Party may at any time and
from time to time, either before or after the maturity thereof, without notice
to or further consent of Guarantor, extend the time of performance or payment
of, exchange or surrender, or fail to act hereunder or under any other agreement
or to perfect, collateral for, or renew any of the Guaranteed Obligations owed
to it, and may also make any agreement with the Obligor, for the extension,
renewal, payment, compromise, discharge or release thereof, in whole or in part,
or for

                                        3

<PAGE>

any modification of the terms thereof, without in any way impairing or affecting
the obligations of the Guarantor pursuant to this Article II.

Section 2.02 Effectiveness and Term. The guarantee provided in this Article II
is a continuing guarantee and shall apply to all Guaranteed Obligations whenever
arising. This Guarantee shall terminate upon the earlier of (i) full payment of
all Senior Facility Loan Obligations owed to the Senior Facility Lenders, (ii)
the date of termination of the Operator's Agreement, or (iii) the date as of
which neither the Operator nor any Guaranteed Successor is a party to the
Operator's Agreement, provided, that in the event of a termination pursuant to
this clause (ii) or (iii), this Guarantee shall survive until all Guaranteed
Obligations arising prior to such date have been performed, paid or otherwise
discharged in full (x) in the event of a performance or payment by Obligor, in
accordance with the provisions of the Operator's Agreement and (y) in the event
of a performance or payment by Guarantor, in accordance with this Guarantee.

Section 2.03 Payments. With respect to payments to be made by Guarantor under
this Guarantee, all such payments shall be made in the currency in which such
payment was required to be made by Obligor, by the deposit of immediately
available funds by wire transfer into the Proceeds Account. All payments
required to be made by Guarantor hereunder shall be made in accordance with the
same terms as if made by the Obligor under the Operator's Agreement.
Accordingly, the obligation of Guarantor for payment under this Guarantee shall
be discharged solely by payment in the manner provided herein and not by payment
to any other Person or at any other place.

                                   ARTICLE III
                              CONSENT TO ASSIGNMENT

Section 3.01 Guaranteed Party May Assign to the Offshore Collateral Agent.
Guaranteed Party shall be entitled to grant, transfer and assign to the Offshore
Collateral Agent, as collateral agent for the benefit of the Senior Lenders
named in the Master Security Agreement, all right, title and interest which
Guaranteed Party now has or which shall hereafter arise in and to this Guarantee
and all amounts due and to become due to Guaranteed Party hereunder or in
respect hereof and all claims resulting from any failure of performance or
compliance with any of the provisions of this Guarantee, together with full
power and authority, in its own name or in the name of Guaranteed Party or
otherwise, to enforce and request payment under this Guarantee against Guarantor
and to collect, receive and give receipts and releases for such amounts.
Guarantor hereby irrevocably consents to such grant, transfer and assignment
and, in the event of a Borrower Enforcement Action, to the exercise by the
Offshore Collateral Agent (on behalf of the Senior Lenders) of its rights as a
secured party in accordance with Section 3.02(a)(i) of the Master Security
Agreement. Guarantor hereby irrevocably further agrees for the benefit of the
Offshore Collateral Agent (on behalf of the Senior Lenders) to make any and all
payments required hereunder or in respect hereof directly to the Proceeds
Account and agrees that the place of payment shall be of the essence under this
Guarantee.

Section 3.02 Notice of Lenders' Reliance. Guarantor acknowledges that the
Offshore Collateral Agent has notice of and is relying on this Guarantee and,
accordingly, that Guarantor's

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<PAGE>

obligations hereunder are directly enforceable against it by the Offshore
Collateral Agent, acting on behalf of the Senior Lenders pursuant to a Borrower
Enforcement Direction, as third party beneficiary of and assignee under this
Guarantee.

Section 3.03 Offshore Collateral Agent to Receive Notice of Breach and
Termination. Guarantor agrees that the Offshore Collateral Agent shall be given
prompt written notice of any material breach, termination or claim of
termination of this Guarantee.

                                   ARTICLE IV
                         REPRESENTATIONS AND WARRANTIES

Section 4.01 Representations and Warranties of Guarantor. Guarantor represents
and warrants to Guaranteed Party that:

          (a) Organization. It is a corporation duly organized, validly existing
and is in good standing under the laws of the State of New York.

          (b) Authority. It has full power and authority to execute and deliver
this Guarantee and to perform its obligations hereunder in accordance with the
terms provided herein.

          (c) Binding Agreement. This Guarantee has been duly authorized,
executed and delivered by it and constitutes a valid and legally binding
agreement, enforceable in accordance with its terms, subject to bankruptcy,
insolvency, fraudulent conveyance, reorganization, moratorium and similar laws
of general applicability relating to or affecting creditors' rights and to
general equity principles.

          (d) Consents and Approvals for this Guarantee. All Governmental
Approvals which are necessary for the execution and delivery by it of this
Guarantee and the performance of its obligations hereunder have been obtained
and are in full force and effect.

          (e) Conflicts. There is no provision of law, statute, regulation,
rule, order, injunction, decree, writ or judgment, no provision of its
organizational documents and no provision of any mortgage, indenture, contract
or agreement binding on it or affecting its properties, which would prohibit,
conflict with or in any way prevent its execution, delivery, or performance of
the terms of this Guarantee.

          (f) No Immunity. It does not have any immunity from jurisdiction of
any court or from any legal process (whether through service, notice, attachment
prior to judgment, attachment in aid of execution, execution or otherwise).

          (g) Litigation. There is no action, suit, proceeding or investigation,
at law or in equity, or before any Governmental Authority or other Person,
pending or, to the best knowledge of Guarantor, threatened, against or affecting
Guarantor or its assets that (i) questions the validity of this Guarantee or any
action taken or to be taken pursuant hereto or thereto, or (ii) in any case or
in the aggregate would reasonably be expected to result in a material adverse
effect on the ability of Guarantor to perform its obligations hereunder.

                                        5

<PAGE>

          (h) Ranking. Its obligations under this Guarantee shall rank pari
passu with all other unsecured obligations of Guarantor.

                                    ARTICLE V
                        CONSENT TO SUIT AND JURISDICTION

Section 5.01 Consent to Suit and Jurisdiction. Guarantor hereby irrevocably
consents and agrees, for the benefit of the Guaranteed Party and the Offshore
Collateral Agent, that any legal action, suit or proceeding against it with
respect to its obligations, liabilities or any other matter under or arising out
of or in connection with this Guarantee may be brought in any Federal or State
court located in New York County in the City of New York and hereby irrevocably
accepts and submits to the non-exclusive jurisdiction of such court with respect
to any such action, suit or proceeding. Guarantor hereby waives any objection
which it may now or hereafter have to the laying of venue of any of the
aforesaid actions, suits or proceedings, brought in any such court and hereby
further waives and agrees not to plead or claim in any such court that any such
action, suit or proceeding brought therein has been brought in an inconvenient
forum.

Section 5.02 Guarantor's Agent for Service of Process. Guarantor hereby
irrevocably appoints CT Corporation, with offices at the date of this Guarantee
at 111 Eighth Avenue, New York, NY 10011, U.S.A., as Guarantor's authorized
agent on which any and all legal process may be served in any such action, suit
or proceeding brought by or on behalf of the Guaranteed Party or the Offshore
Collateral Agent in the United States Federal courts located in the Borough of
Manhattan, The City of New York or the courts of the State of New York located
in the Borough of Manhattan, The City of New York. Guarantor agrees that service
of process in respect of it upon such agent, together with written notice of
such service given as provided in Section 6.01, shall be deemed to be effective
service of process upon it in any such action, suit or proceeding. Guarantor
agrees that the failure of such agent to give notice to it of any such service
shall not impair or affect the validity of such service or any judgment rendered
in any action, suit or proceeding based thereon. If for any reason such agent
shall cease to be available to act as such, Guarantor agrees that it shall
designate a new agent in the Borough of Manhattan, The City of New York on the
terms and for the purposes of this Article V. Nothing herein shall in any way be
deemed to limit the ability of the Offshore Collateral Agent to serve any such
legal process in any other manner permitted by applicable law or to obtain
jurisdiction over the Guarantor or bring actions, suits or proceedings against
it in such other jurisdictions, and in such manner, as may be permitted by
applicable law.

                                   ARTICLE VI
                                  MISCELLANEOUS

Section 6.01 Notices. Any notice, request, demand, consent, designation,
direction, instruction, certificate, report or other communication to be given
hereunder shall be given in the English language and will be duly given when
delivered in writing or sent by facsimile transmission (with written
confirmation of receipt, which confirmation may be by facsimile transmission) to
a Party

                                        6

<PAGE>

at its address and facsimile transmission number as indicated below or to such
other address as may be furnished for this purpose by such Party at:

     If to Guarantor, at:

          Phelps Dodge Tower
          1 North Central Avenue
          Phoenix, Arizona 85004
          U.S.A.
          Attention: Treasurer
          Telephone: (602) 366-8100
          Facsimile: (602) 366-8150

     If to Guaranteed Party at:

          SOCIEDAD MINERA CERRO VERDE S.A.A.
          c/o Asiento Minero Cerro Verde
          Uchumayo (Arequipa/Peru), Casilla Postal #299
          Shipping: Av. Alfonso Ugarte #304
          Cercado, Arequipa, Republic of Peru
          Attention: General Manager
          Telecopier (Fax): 054-28-33-76

     If to the Offshore Collateral Agent, at:

          Citibank N.A.
          Citibank Agency & Trust
          388 Greenwich Street
          14th Floor
          New York, NY 10013
          Attention: Jenny Cheng
          Telephone: 212 816 5648
          Facsimile: 212 816 5530

or at such other address as any Party shall have specified by notice to the
other Parties in accordance with this Section.

Section 6.02 Successors and Assigns. This Guarantee shall be binding upon and
inure to the benefit of the Guarantor and the Guaranteed Party and their
respective successors and assigns. Except as set forth in Article III, the
Parties may not assign or transfer any of their rights or obligations under this
Guarantee without the prior written consent of the other party.

Section 6.03 Waiver of set-off. Guarantor hereby agrees, for the benefit of the
Offshore Collateral Agent that the obligations of Guarantor to pay amounts due
hereunder shall not be subject to any counterclaim, set-off, deduction or
defense against Guaranteed Party by reason of any claim that Guarantor may have
against Guaranteed Party arising out of a transaction that is not a subject of
this Guarantee.

                                        7

<PAGE>

Section 6.04 Confidentiality. Each Party shall maintain the confidentiality of
the terms and contents of this Guarantee and shall not disclose the terms and
contents of this Guarantee to any third parties except (a) with the prior
consent of the other Party, (b) as may be required to satisfy an audit by public
accountants during a review of the financial condition and/or statements of
either Party, (c) as required by law or court order or (d) that such terms and
contents may be disclosed to prospective (direct and indirect) lenders and to
the parties to the MSA.

Section 6.05 Execution in Counterparts. This Guarantee may be executed in any
number of counterparts and by the different parties hereto on separate
counterparts, each of which when so executed and delivered shall be an original,
but all the counterparts shall together constitute one and the same instrument.

Section 6.06 Amendments.

          (a) Neither this Guarantee nor any terms hereof may be amended,
supplemented or modified other than pursuant to a written instrument executed by
the Guaranteed Party, the Guarantor and the Offshore Collateral Agent.

          (b) No waiver by the Guaranteed Party of any of its rights, powers and
privileges under this Guarantee shall be effective other than pursuant to a
written instrument executed by the Guaranteed Party and the Offshore Collateral
Agent waiving such right, power or privilege.

Section 6.07 Effectiveness. This Guarantee shall come into full force and effect
upon its execution and delivery by each of the Parties.

Section 6.08 No Trial by Jury. Each Party hereby waives, to the fullest extent
permitted by applicable law, any and all right to trial by jury in any legal
proceeding arising out of or relating to this Guarantee or the transactions
contemplated hereby.

Section 6.09 Severability. If any provision of this Guarantee shall be invalid,
illegal or unenforceable, the parties hereto agree to the fullest extent they
may effectively do so that the validity, legality and enforceability of the
remaining provisions shall not in any way be affected or impaired thereby; and
the invalidity of a particular provision in a particular jurisdiction shall not
invalidate such provision in any other jurisdiction.

Section 6.10 GOVERNING LAW. THIS GUARANTEE SHALL BE GOVERNED BY, AND CONSTRUED
IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

                                        8

<PAGE>

          IN WITNESS WHEREOF, the parties hereto have caused this Guarantee to
be duly executed as of the day and year first above written.

                                        PHELPS DODGE CORPORATION,

                                        Guarantor

                                        By /s/ Stanton K. Rideout
                                           -------------------------------------
                                        Name: Stanton K. Rideout
                                        Title: Vice President & Treasurer

AGREED AND ACCEPTED AS OF THE DATE FIRST SET FORTH ABOVE:

                                        SOCIEDAD MINERA CERRO VERDE S.A.A.,

                                        Guaranteed Party

                                        By /s/ Cristian Moran
                                           -------------------------------------
                                        Name: Cristian Moran
                                        Title: Attorney in Fact

                                        9

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