<PAGE>
                                                                    Exhibit 10.6

                                                                  EXECUTION COPY

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                               KFW LOAN AGREEMENT

                                     between

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

                                       and

                                      KfW,
                                    as Lender

                         Dated as of September 30, 2005

                                  US$22,500,000

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

<PAGE>

                                TABLE OF CONTENTS

          This table of contents is not part of the Agreement to which it is
attached, but is inserted for convenience only.

<TABLE>
<CAPTION>
                                                                            Page
                                                                            ----
<S>                                                                         <C>
ARTICLE I DEFINITIONS....................................................     1
   1.01 Definitions......................................................     1
   1.02 Other Definitions; Interpretation................................     3
   1.03 Incorporation by Reference.......................................     3
   1.04 Types of Loans...................................................     4

ARTICLE II THE LOANS.....................................................     4
   2.01 Loans............................................................     4
   2.02 Manner of Borrowing..............................................     4
   2.03 Certain Notices..................................................     5
   2.04 Conversions into Fixed Rate Loans................................     5
   2.05 Reduction in Commitment..........................................     5
   2.06 Availability Period..............................................     5

ARTICLE III PRINCIPAL, INTEREST AND PROMISSORY NOTES.....................     5
   3.01 Principal........................................................     5
   3.02 Interest.........................................................     5
   3.03 Post-Default Interest............................................     6
   3.04 Promissory Notes.................................................     6
   3.05 Selection of Fixed Rates.........................................     7
   3.06 Consolidation of Applicable Base Rate for Fixed Rate Loans.......     7

ARTICLE IV COMMISSIONS...................................................     7
   4.01 Commitment Commission............................................     7
   4.02 Loan Management Commission.......................................     7
   4.03 Facility Fee.....................................................     7

ARTICLE V THE HERMES GUARANTEE...........................................     8
   5.01 The HERMES Guarantee.............................................     8
   5.02 Information......................................................     8
   5.03 KfW's Right to Demand Information and Give Approval Regarding
           Export Contracts..............................................     8

ARTICLE VI PREPAYMENT....................................................     8
   6.01 Voluntary Prepayments............................................     8
   6.02 Pro Rata Prepayment..............................................     9
   6.03 Prepayment Compensation for Fixed Rate Loans.....................     9
   6.04 Mandatory Prepayments............................................    10
</TABLE>

                               KfW Loan Agreement

<PAGE>

                                      -ii-


<TABLE>
<S>                                                                         <C>
ARTICLE VII PAYMENTS.....................................................    10
   7.01 Payments.........................................................    10
   7.02 Non-Business Days................................................    10
   7.03 Computations.....................................................    11

ARTICLE VIII CERTAIN INDEMNITIES.........................................    11
   8.01 Increased Cost of Loans..........................................    11
   8.02 Alternative Interest Rate........................................    11
   8.03 Mitigation.......................................................    12

ARTICLE IX CONDITIONS OF LENDING.........................................    12
   9.01 Initial Loan.....................................................    12
   9.02 Additional Conditions............................................    13

ARTICLE X COVENANTS......................................................    14

ARTICLE XI REPRESENTATIONS AND WARRANTIES................................    14

ARTICLE XII EVENTS OF DEFAULT; REMEDIES..................................    14
   12.01 Events of Default...............................................    14
   12.02 Remedies........................................................    14
   12.03 Suspension, Cancellation or Termination of Commitment...........    14

ARTICLE XIII MISCELLANEOUS...............................................    14
   13.01 No Waiver.......................................................    14
   13.02 No Immunity.....................................................    15
   13.03 Jurisdiction and Service of Process.............................    15
   13.04 GOVERNING LAW...................................................    15
   13.05 Assignments and Participations; Information.....................    15
   13.06 Amendments, Etc.................................................    16
   13.07 Counterparts....................................................    16
   13.08 Judgment Currency...............................................    16
   13.09 Successors and Assigns..........................................    16
   13.10 Stamp Taxes.....................................................    16
   13.11 Survival........................................................    17
   13.12 Severability....................................................    17
   13.13 WAIVER OF JURY TRIAL............................................    17
   13.14 Notices.........................................................    17
   13.15 English Language................................................    17
   13.16 No Restriction..................................................    17
</TABLE>

EXHIBIT A - Amortization Schedule

EXHIBIT B - Form of Promissory Note

EXHIBIT C - Form of KfW Loan Agreement Drawdown Certificate

                               KfW Loan Agreement

<PAGE>

                               KfW LOAN AGREEMENT

          KfW LOAN AGREEMENT dated as of September 30, 2005 (this "Agreement")
between SOCIEDAD MINERA CERRO VERDE S.A.A., a sociedad anonima abierta organized
under the laws of Peru (the "Borrower"), and KfW, a corporation under the public
law of the Federal Republic of Germany ("KfW").

          KfW is majority-owned by the German government and in accordance with
its Bylaws and institutional objectives, KfW has agreed to grant a credit
facility to the Borrower for purposes of developing and promoting mining
activities in Peru.

          For purposes of financing in part the development by the Borrower of
the Sulfide Project (referred to in the Master Participation Agreement referred
to below), the Borrower is entering into various loan and credit agreements,
including this Agreement, setting out the terms upon which financing is to be
provided for such development. In conjunction therewith, the Borrower, KfW,
JBIC, the Lead JBIC Arrangers, the Commercial Banks and the Administrative Agent
are entering into a master participation agreement (the "Master Participation
Agreement"), containing certain representations, covenants, undertakings and
security for the common benefit of the Senior Facility Lenders providing the
Senior Facility Loans (as defined in the Master Participation Agreement). Also
in connection therewith, the Parent Companies shall enter into a transfer
restrictions agreement (the Transfer Restrictions Agreement referred to in the
Master Participation Agreement), for the common benefit of such Senior Facility
Lenders, and the Parent Companies shall enter into a Completion Guarantee (the
Completion Guarantee referred to in the Master Participation Agreement)
guaranteeing the payment of the Senior Loan Obligations until Completion and
containing undertakings regarding Completion of the Sulfide Project. Based on
the foregoing, KfW is prepared, on the terms and subject to the conditions set
forth herein and in the other Financing Documents, to make Loans to the Borrower
that constitute Loans in an aggregate principal amount up to US$22,500,000 for
the purchase of equipment and services delivered by the Exporter under the
Export Contracts in connection with the development of the Sulfide Project.

          Accordingly, the parties hereto hereby agree as follows:

                                    ARTICLE I

                                   DEFINITIONS

          1.01 Definitions. Terms defined in this Agreement shall have their
respective defined meanings as provided herein. Capitalized terms used herein
(including the preamble and recital of this Agreement) and not otherwise defined
herein shall have the meanings assigned to such terms in the Master
Participation Agreement (including Schedule Z thereto). As used in this
Agreement, the following terms shall have the following respective meanings:

          "Applicable Base Rate" shall mean:

          (a) for each Floating Rate Loan during each Interest Period or Default
     Interest Period therefor, the interest rate per annum for Dollar deposits
     for a period equal to (or, if there is no equal, then most comparable to)
     such Interest Period or Default Interest Period

                               KfW Loan Agreement

<PAGE>

                                       -2-


     which appears on Reuters Screen LIBOR01 Page (or such other page as may
     replace that page on that service for the purpose of displaying the British
     Bankers Association Interest Settlement Rate) at or about 11:00 a.m. London
     time on the date two Eurodollar Business Days prior to the first day of
     such Interest Period or Default Interest Period; provided that, if no such
     rate appears on Reuters Screen LIBOR01 Page (or such other page as may
     replace that page on that service for the purpose of displaying the British
     Bankers Association Interest Settlement Rate) for any relevant Interest
     Period or Default Interest Period, the Applicable Base Rate shall mean for
     each Loan during such Interest Period or Default Interest Period the rate
     per annum determined by KfW which appears on the page designated Page 3750
     on the Moneyline Telerate Inc. at or about 11:00 a.m. London time on the
     date two Eurodollar Business Days prior to the first day of such Interest
     Period or Default Interest Period; and provided further that if no such
     rates so appear on the page designated Page 3750 on the Moneyline Telerate
     Inc. for any relevant period, the relevant rate of interest shall be
     determined in accordance with Section 8.03 hereof.

          (b) for each Fixed Rate Loan during each Fixed Rate Period therefor,
     the rate per annum equal to the funding costs of KfW in Dollars of a KfW
     Loan for maturities matching as closely as possible the maturity of the
     requested KfW Loan.

          "Default Interest Period" shall mean each successive period (not in
excess of six months) while any amount payable by the Borrower hereunder is in
default, as KfW shall choose in its sole discretion, the first such period to
commence as of the date on which such amount in default becomes due and each
succeeding such period to commence immediately upon the expiry of the
immediately preceding such period.

          "Default Margin" shall mean a rate per annum equal to 2%.

          "Drawdown Certificate" shall have the meaning given to that term in
Section 9.02(b) hereof.

          "Export Contracts" shall mean (i) the agreement between Fluor Daniel
Sucursal Del Peru ("Fluor") and Exporter, dated March 15, 2005, for the purchase
of 4 High Pressure Grinding Rolls in a total amount of US$20,092,452.57 and (ii)
the agreement between Fluor and Exporter, dated February 18, 2005, for the
purchase of 4 ball mills in a total amount of US$10,620,502.51, each in
connection with the Sulfide Project.

          "Exporter" shall mean Polysius AG, an entity domiciled in Germany that
has entered into certain contracts for the supply of goods and/or the rendering
of services in connection with the Sulfide Project.

          "Facility Fee" shall have the meaning assigned to such term in Section
4.03 hereof.

          "Fixed Rate Loans" shall mean Loans the interest rates on which are
determined on the basis of rates referred to in clause (b) in the definition of
"Applicable Base Rate" in this Section 1.01.

                               KfW Loan Agreement

<PAGE>

                                       -3-


          "Fixed Rate Period" shall mean, for each Fixed Rate Loan, the period
from the date such Loan is made or converted from a Floating Rate Loan into a
Fixed Rate Loan until the maturity of the Loan.

          "Floating Rate Loans" shall mean Loans the interest rates on which are
determined on the basis of rates referred to in clause (a) in the definition of
"Applicable Base Rate" in this Section 1.01.

          "Frankfurt Business Day" shall mean any day on which banks are
generally open for business in Frankfurt Germany.

          "German Supply Portion" shall mean those items of equipment and
services of German origin which have been provided by the Exporters pursuant to
the Export Contracts.

          "Germany" shall mean the Federal Republic of Germany.

          "Head Office" shall mean the principal office of KfW in Germany,
presently located at PalmengartenstraBe 5-9, D-60325 Frankfurt am Main, Germany.

          "HERMES" shall mean Euler Hermes Kreditversicherungs-AG acting on
behalf of the government of the Federal Republic of Germany.

          "HERMES Guarantee" shall mean the insurance coverage to be provided by
HERMES in favor of KfW in respect of the Borrower's obligations under this
Agreement, which shall be in form and substance satisfactory to KfW.

          "KfW Loans" or "Loans" shall mean the loans provided for in Section
2.01 hereof, which may be Floating Rate Loans and/or Fixed Rate Loans.

          "Margin" shall mean 0.35% per annum.

          "Master Participation Agreement" shall have the meaning assigned to
such term in the recitals of this Agreement.

          "Reuters Screen LIBOR01 Page" shall mean the display page so
designated on the Reuter Monitor Money Rates Service (or such other page as may
replace that page on that service for the purpose of displaying London interbank
offered rates for Dollar deposits).

          "Type" shall have the meaning given to that term in Section 1.04
hereof.

          "U.S." shall mean the United States of America.

          1.02 Other Definitions; Interpretation. This Agreement shall be
interpreted in accordance with the rules of interpretation set forth in Section
1.02 of the Master Participation Agreement, which are incorporated by reference
herein as if fully set forth herein.

          1.03 Incorporation by Reference. This Agreement and the Master
Participation Agreement shall be viewed as, and shall constitute, one agreement
governing the terms and

                               KfW Loan Agreement

<PAGE>

                                      -4-


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.

          1.04 Types of Loans. Loans hereunder are distinguished by "Type". The
"Type" of a Loan refers to whether such Loan is a Floating Rate Loan or a Fixed
Rate Loan, each of which constitutes a Type.

                                   ARTICLE II

                                    THE LOANS

          2.01 Loans. KfW agrees, upon the terms and conditions of this
Agreement and the Master Participation Agreement, to make Loans to the Borrower
from time to time in such aggregate principal amount not exceeding its Aggregate
Committed Amount, and on such Business Days during the period from the date
hereof to but excluding the Availability Period End Date as the Borrower shall
request pursuant to Section 2.02 hereof. KfW's Aggregate Committed Amount shall
be utilized for the following purposes: (i) an aggregate principal amount not to
exceed approximately US$20,670,300 to finance or reimburse the Borrower for
expenses incurred in connection with up to 85% of the German Supply Portion and
(ii) an aggregate amount not to exceed approximately US$1,829,700 to finance or
reimburse the Borrower for expenses incurred in connection with up to 100% of
the Facility Fee, collectively not to exceed, in any event, US$22,500,000 in the
aggregate.

          The Loans may be borrowed as Fixed Rate Loans or as Floating Rate
Loans. Floating Rate Loans may be converted into Fixed Rate Loans as provided in
Section 2.04 hereof.

          The Loans shall be advanced from time to time, but in no event more
frequently than once per calendar month, in accordance with the terms of this
Agreement and the Master Participation Agreement. Any amounts borrowed and paid
or prepaid pursuant to the terms herein may not be reborrowed by the Borrower.

          The Borrower shall not be relieved of its obligations under this
Agreement to pay all amounts due and payable on the relevant due date by reason
of the KfW Loans being insufficient to finance up to 100% of the Facility Fee
under this Agreement.

          2.02 Manner of Borrowing. The Borrower shall give KfW not less than
fifteen (15) Business Days' prior notice (which notice shall be copied to the
Trustee and the Administrative Agent and shall be irrevocable and effective upon
receipt) specifying the date and amount of each borrowing hereunder, such notice
to be substantially in the form of Exhibit C and specifying whether the Borrower
requests a Floating Rate Loan or a Fixed Rate Loan. Except as to the borrowing
which utilizes the unborrowed portion of the Commitment in full, each borrowing
of Loans shall be in a minimum amount of US$500,000. No more than one borrowing
may be requested in any calendar month. The proceeds of each Loan shall be made
available directly to the Borrower by KfW in Dollars, on the respective
borrowing date, by credit

                               KfW Loan Agreement

<PAGE>

                                      -5-


to the Onshore Dollars Account, thus reimbursing the Borrower for payments
already made under the respective Export Contract, provided that the conditions
precedent set forth in Section 9.01 have been met.

          2.03 Certain Notices. The Borrower shall notify KfW in writing (which
notice shall be irrevocable and effective upon receipt), at least five (5)
Frankfurt Business Days prior to the end of an Interest Period for any Floating
Rate Loan, if the Borrower wishes to convert such Loan into a Fixed Rate Loan
pursuant to Section 2.04 hereof.

          2.04 Conversions into Fixed Rate Loans. The Borrower shall have the
right to convert Floating Rate Loans into Fixed Rate Loans; provided that (a)
the Borrower shall give KfW notice of each such conversion pursuant to Section
2.03 hereof; (b) each such conversion shall be in a minimum amount of
US$500,000, provided, however, that the Borrower may convert any Floating Rate
Loans outstanding as of the Availability Period End Date in an amount less than
US$500,000; and (c) a Floating Rate Loan may be so converted only on the last
day of an Interest Period for such Loan. Upon conversion of Floating Rate Loans
to Fixed Rate Loans all subsequent disbursements shall be made as Fixed Rate
Loans. For the avoidance of doubt, once the Borrower shall have converted
Floating Rate Loans to Fixed Rate Loans, the Borrower shall not be permitted to
revert any such Loans back to Floating Rate Loans.

          2.05 Reduction in Commitment. 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.

          2.06 Availability Period. The facility will be available from the date
on which the conditions precedent set forth in Section 5.01 of the Master
Participation Agreement are fulfilled through the Availability Period End Date.

                                   ARTICLE III

                    PRINCIPAL, INTEREST AND PROMISSORY NOTES

          3.01 Principal. The Borrower agrees to repay the principal amount of
each Loan in 16 consecutive semi-annual installments on each Payment Date,
commencing on the first Payment Date in accordance with the Amortization
Schedule set forth in Exhibit A; provided, however, that the 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. The Borrower agrees to pay KfW interest on the
Outstanding Base Amount of each Loan for the period from and including the date
of such Loan to but excluding the date such Loan shall be paid in full, at the
following rates per annum:

          (a) during such periods as such Loan is a Floating Rate Loan, for each
     Interest Period relating thereto, the Applicable Base Rate for such
     Floating Rate Loan for such Interest Period plus the applicable Margin
     plus, upon the occurrence and during the Continuance of any MPA Event of
     Default under Section 9.01 of the Master Participation Agreement, the
     Default Margin; and

                               KfW Loan Agreement

<PAGE>

                                      -6-


          (b) during such periods as such Loan is a Fixed Rate Loan, for each
     Fixed Rate Period relating thereto, the Applicable Base Rate for such Fixed
     Rate Loan for such Fixed Rate Period plus the applicable Margin plus, upon
     the occurrence and during the Continuance of any MPA Event of Default under
     Section 9.01 of the Master Participation Agreement, the Default Margin.

Interest shall accrue (i) in the case of a Fixed Rate Loan, from and including
the date of such Loan in case of the first interest payment with respect to any
Advance or from and including the Interest Payment Date to which interest has
been paid in case of the second and any subsequent interest payments with
respect to each Advance to but excluding the next succeeding Interest Payment
Date or, in the case of payment pursuant to clause (B) below, to but excluding
the date of such payment, and (ii) in the case of a Floating Rate Loan, from and
including the first day of each Interest Period for such Loan to but excluding
the last day of such Interest Period or, in the case of payment pursuant to
clause (B) or (C) below, to but excluding the date of such payment. Accrued
interest on each Loan shall be payable (A) on each Interest Payment Date; (B)
upon the payment or prepayment thereof (on the principal amount so paid or
prepaid); and (C) in the case of a Floating Rate Loan, upon the conversion of
such Loan to a Fixed Rate Loan (on the principal amount so converted). Each
Interest Period for a Floating Rate Loan shall (y) comply with the definition of
the term "Interest Period" and (z) except for the first Interest Period for a
Floating Rate Loan, will have a duration of six months.

          3.03 Post-Default Interest. If any installment of principal of any
Loan or any other amount (including interest on a Loan) payable by the Borrower
hereunder is not paid in full when due (whether at the stated due date, by
acceleration or otherwise), the Borrower hereby agrees to pay from time to time
upon KfW's 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
be due and unpaid, at a rate per annum equal to the sum of (a) the Margin plus
(b) the Default Margin plus (c) (i) in the case of Fixed Rate Loan, during a
Fixed Rate Period therefor, the Applicable Base Rate therefor, and (ii) in all
other cases, the Applicable Base Rate for Floating Rate Loans for such Default
Interest Period.

          3.04 Promissory Notes.

          (a) As additional evidence of the Borrower's obligation to pay the
principal of the Loans as provided in Section 3.01 hereof, the Borrower shall
execute and deliver to the Trustee on behalf of KfW Promissory Notes issued by
the Borrower, in substantially the form set forth in Exhibit B hereto, with a
dual column translation into Spanish to be included therein, in accordance with
Section 2.08 of the Master Participation Agreement.

          (b) The execution and delivery by the Borrower of the Promissory Notes
shall not affect in any way whatsoever the rights or obligations of the Borrower
under this Agreement, and the rights and claims of KfW under the Promissory
Notes held by it shall not replace or supersede the rights and claims of KfW
hereunder, provided that payment of any part of the principal of any such
Promissory Note in accordance with the terms of this Agreement shall, to the
extent that such payment if made hereunder would discharge the Borrower's
obligations hereunder in respect of the payment of the principal of the Loan
evidenced by such Promissory

                               KfW Loan Agreement

<PAGE>

                                      -7-


Note, discharge such obligation pro tanto and the payment of any principal of a
Loan in accordance with the terms and conditions hereof shall discharge the
obligations of the Borrower under the Promissory Note evidencing such Loan to
the extent of such payment.

          3.05 Selection of Fixed Rates. Not more than 15 and not less than
seven Business Days prior to a proposed borrowing of a Loan hereunder or prior
to the last day of an Interest Period for any Floating Rate Loan, the Borrower
may request that KfW advise the Borrower on an indicative basis (which shall not
be binding) of KfW's best estimate of what the expected Applicable Base Rate
would be for a Fixed Rate Loan with a Fixed Rate Period commencing on the date
of borrowing of the proposed Loan or on the last day of such Interest Period, as
the case may be, and ending on the Final Maturity Date; provided, however, that
any change in such Applicable Base Rate from that so advised by KfW shall result
only from a change in KfW's funding costs.

          3.06 Consolidation of Applicable Base Rate for Fixed Rate Loans. In
the event that more than one Fixed Rate Loan is outstanding, KfW may in its own
discretion consolidate the Applicable Base Rates for Fixed Rate Loans
outstanding on such date into a single interest rate corresponding to the
weighted average of the Applicable Base Rates for such Fixed Rate Loans, rounded
down to 1/10,000 if the fifth decimal to be omitted is below 5 or rounded up to
1/10,000 if the fifth decimal to be omitted is 5 or above. Commencing with the
first Payment Date following such consolidation, such weighted average interest
rate shall constitute the Applicable Base Rate for the further computation and
payment of interest for such consolidated Fixed Rate Loans.

                                   ARTICLE IV

                                   COMMISSIONS

          4.01 Commitment Commission. The Borrower agrees to pay KfW a
commitment commission on the daily unborrowed amount of the Commitment which may
be reduced or terminated as contemplated in Section 2.03 of the Master
Participation Agreement for the period from and including the date of this
Agreement to but excluding the earliest of (a) the date the Commitment is
borrowed in full, (b) the date the Commitment is terminated and (c) the
Availability Period End Date, at a rate per annum equal to 0.25%. Accrued
commitment commission under this Section 4.01 shall be payable quarterly, in
arrears, on each Interest Payment Date and on each date falling three calendar
months after each such Interest Payment Date, with the last installment of the
commitment commission hereunder to be paid on the Availability Period End Date.

          4.02 Loan Management Commission. The Borrower shall pay to KfW an
upfront fee equal to 1% of the Commitment (determined as of the date of this
Agreement) payable within 30 days from and after the date of this Agreement.

          4.03 Facility Fee. On the date of disbursement of the initial Advance,
the Borrower agrees to pay a facility fee (the "Facility Fee") in such amount as
KfW shall determine is necessary to compensate it for costs and expenses
associated with the HERMES Guarantee. The Facility Fee as determined by KfW
shall be binding on the Borrower. If the Facility Fee or a

                               KfW Loan Agreement

<PAGE>

                                      -8-


portion thereof is refunded to KfW by HERMES, KfW shall reimburse the Borrower
in an amount equal to the amount refunded to KfW by HERMES promptly upon receipt
of such refund from HERMES. If the Facility Fee exceeds the amount set forth in
Section 2.01, the Borrower shall pay the full amount of the Facility Fee
(including such excess) to KfW in accordance with this Section 4.03.

                                    ARTICLE V

                              THE HERMES GUARANTEE

          5.01 The HERMES Guarantee. KfW's rights to receive payment from the
Borrower under this Agreement shall be guaranteed by the Federal Republic of
Germany, pursuant to the HERMES Guarantee.

          5.02 Information. Subject to Section 12.10 of the Master Participation
Agreement and the generally applicable procedures of KfW in respect of
confidential commercial information, KfW shall be entitled to give information
relating to the Sulfide Project and to the KfW Loan Agreement to representatives
of the Federal Republic of Germany having any responsibility in connection with
the HERMES Guarantee and its representatives and advisors. Furthermore, subject
to Section 12.10 of the Master Participation Agreement and the generally
applicable procedures of KfW in respect of confidential commercial information,
KfW and the representatives of the Federal Republic of Germany shall be entitled
to give information relating to the KfW Loan Agreement to international
organizations entrusted with the collection of statistical data, particularly
data in connection with debt servicing.

          5.03 KfW's Right to Demand Information and Give Approval Regarding
Export Contracts. The Borrower shall inform KfW without delay of any event that,
in its reasonable judgment, could be reasonably expected to materially impede or
endanger the implementation of the Export Contracts according to schedule. The
Borrower shall not, without the prior written consent of KfW (which may not be
unreasonably withheld), agree to any modification of or amendment to the Export
Contracts that (a) reduces the total price of the Export Contracts below
US$22,500,000 or (b) changes the Exporter under such Export Contracts. In
addition, the Borrower shall inform KfW without delay of its own accord of any
modification of or amendment to the Export Contracts that may materially affect
the volume of goods and services or any other material provision of the Export
Contracts. The Borrower shall on demand furnish any information reasonably
requested by KfW regarding the Export Contracts.

                                   ARTICLE VI

                                   PREPAYMENT

          6.01 Voluntary Prepayments.

          (a) The Borrower shall have the right to prepay the Loans, in whole or
in part, without premium or penalty other than as required by Sections 6.01(b)
and Section 6.03 hereof, at any time or from time to time in accordance with
Section 3.05 of the Master Participation Agreement; provided, however, that each
prepayment of a Fixed Rate Loan, and each prepayment of a Floating Rate Loan on
a date other than the last day of the then current Interest

                               KfW Loan Agreement

<PAGE>

                                      -9-


Period, shall be accompanied by, and the Borrower hereby agrees to pay to KfW on
the date of such prepayment, payment of the prepayment compensation (if any)
required under Section 6.03 hereof and reimbursement of funding losses or
expenses (if any) required under Section 3.11 of the Master Participation
Agreement. Partial prepayment shall be applied to the Loans in accordance with
Section 3.08 of the Master Participation Agreement.

          (b) Notwithstanding any provision herein to the contrary, if the
Borrower makes a voluntary prepayment of all or any portion of the principal
outstanding amount of any Floating Rate Loan or Fixed Rate Loan at any time
prior to the Final Maturity Date with the proceeds of replacement debt obtained
(either at the time or within a period of one year from the date of such
voluntary prepayment) from a Person other than the Parent Companies or an
Affiliate of the Parent Companies, the Borrower shall, on the date that such
replacement debt is obtained, pay to KfW a prepayment fee equal to one-half of
one per cent (0.5%) of the aggregate principal amount of Floating Rate Loans and
Fixed Rate Loans prepaid by the Borrower.

          (c) Notwithstanding any provisions herein to the contrary, if KfW
exercises its rights to suspend, cancel or terminate its aggregate Committed
Amount pursuant to Section 12.03 (other than by reason of, directly or
indirectly, improper acts or inactions of the Borrower), then the Borrower may
prepay all or any portion of any Loan without prepayment premium or penalty of
any kind whatsoever.

          6.02 Pro Rata Prepayment. The extent to which payments or 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. KfW may waive its right to receive any
such prepayment without prejudice to its right to receive any subsequent
prepayment. Each prepayment of Loans under this Section 6.02 shall be
accompanied by the prepayment compensation (if any) required under Section 6.03
hereof and amounts (if any) then payable under Section 3.11 of the Master
Participation Agreement.

          6.03 Prepayment Compensation for Fixed Rate Loans. Without duplication
of any compensation payable under Section 3.11 of the Master Participation
Agreement, upon any payment prior to scheduled maturity (whether pursuant to
this Article VI or Article XII hereof or otherwise) of any principal of any
Fixed Rate Loan, in whole or in part if (a) the sum of the interest payments
which (in the absence of such prepayment) would have been payable on each
installment of such Loan (or portion thereof) so prepaid, on each Payment Date
from the date of such prepayment to the original scheduled maturity date of such
installment, at the applicable rate for such Loan specified in Article III
hereof minus the applicable Margin (for purposes of this Section 6.03, the
"Prepayment Interest") exceeds (b) the sum of the interest payments which would
be received if the principal amount of each installment of such Loan (or portion
thereof) so prepaid were re-invested, for the period from the date of such
prepayment to the original scheduled maturity date hereunder of such
installment, at the Reinvestment Rate (as defined below) (for purposes of this
Section 6.03, the "Reinvestment Interest"), the Borrower agrees to pay KfW a
prepayment commission in respect of each such prepayment in an amount (computed
as of the date of such prepayment) equal to the Present Value (as defined below)
of the amount of such excess.

                               KfW Loan Agreement

<PAGE>

                                      -10-


          For purposes of this Section 6.03, "Reinvestment Rate" shall mean, in
respect of each installment of principal prepaid, the rate which appears on the
Reuters Screen RTRTSY1 Page at or about 4:00 p.m. (Frankfurt time) on a date
selected by KfW occurring on or within five Eurodollar Business Days prior to
the date of such prepayment, for actively traded U.S. Treasury obligations
having substantially the same scheduled maturity as such installment
(interpolating, where appropriate, between the yield to maturity quotations for
the next shorter and next longer maturities for any Loan installment scheduled
to mature at a time for which no such yield quotation is expressed); and the
"Present Value" of any amount receivable or deemed receivable on a specified
future date shall mean such amount discounted to present value (from such
specified future date to the date of such prepayment) at the Reinvestment Rate.

          6.04 Mandatory Prepayments. The Borrower shall make Mandatory
Prepayments as set forth in Section 3.06 of the Master Participation Agreement.
KfW may waive its right to receive any Mandatory Prepayments without prejudice
to its right to receive any subsequent Mandatory Prepayment. Each prepayment of
Loans under this Section 6.04 shall be accompanied by the prepayment
compensation (if any) required under Section 6.03 hereof and amounts (if any)
then payable under Section 3.11 of the Master Participation Agreement.

          In case of mandatory prepayments made in accordance with Section 3.06
of the Master Participation Agreement, the Borrower shall, upon KfW's demand,
prepay the outstanding Loans in full (or in the amount of the affected portion
thereof) together with accrued interest thereon and all other amounts payable to
KfW hereunder (including amounts, if any, payable under Section 6.03 hereof and
Section 3.11 of the Master Participation Agreement), in the case of each
outstanding Floating Rate Loan, on the last day of the then current Interest
Period for such Floating Rate Loan and, in the case of each outstanding Fixed
Rate Loan, on the first Payment Date occurring at least three months after the
date of such demand (or, in the case of any Loan, on such earlier date as shall
be certified by KfW as being the last permissible date for such prepayment under
the relevant law, rule, regulation, treaty or directive).

                                   ARTICLE VII

                                    PAYMENTS

          7.01 Payments. All payments and prepayments on account of the
principal of and interest on the Loans, fees, commissions, indemnities and other
amounts payable under this Agreement or any Promissory Note by the Borrower
shall be made to KfW in Dollars and in immediately available funds, without
set-off, counterclaim or reduction for any reason whatsoever, by credit to an
account designated by KfW at Citibank in New York, New York (Swift Code: BIC
CITIUS33, Account number: 10926093, Account name: KfW) and designating KfW in
Frankfurt am Main, Germany as the beneficiary (Swift Code: KFWIDEE, Payment
Reference: yyyymmdd/Cerro Verde (8137091719), not later than 11:00 a.m. New York
City time on the date on which such payment shall become due.

          7.02 Non-Business Days. If any payment under this Agreement falls due
on a day which is not a Business Day, the due date therefor 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.

                               KfW Loan Agreement

<PAGE>

                                      -11-


          7.03 Computations. Interest hereunder calculated on the basis of the
quotations referred to in clause (a) and clause (b) of the definition of
"Applicable Base Rate" shall be computed on the basis of a year of 360 days and
actual days elapsed. Prepayment compensation under Section 6.04 hereof, shall be
computed on the basis of a year of 365 days (or 366 days, as the case may be)
and actual days elapsed. Commitment commission hereunder shall be computed on
the basis of a year of 360 days and actual days elapsed.

                                  ARTICLE VIII

                               CERTAIN INDEMNITIES

          8.01 Increased Cost of Loans. In the event that, at any time or from
time to time, as a result of any change in any applicable laws (including the
adoption of any new laws), rules, regulations, treaties, directives or requests
of general applicability of any applicable governmental, fiscal or monetary
authority (whether imposing or modifying taxation (other than Excluded Taxes and
Indemnified Taxes, provision for which is made in Section 8.01 hereof), reserve
or special or other deposit requirements or any other requirements or
conditions, and whether or not having the force of law), or in the
interpretation or administration thereof by any court or any such authority
charged with the interpretation or administration thereof (including, without
limitation, any change in the regulations implementing the proposals for a
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
modified and supplemented), or by reason of KfW's compliance with any such law,
rule, regulation, treaty, directive or request, the cost to KfW of making,
maintaining or funding the Loans is increased, or any amount (or the effective
return on any amount) received or receivable by KfW hereunder or under the
Promissory Notes is reduced, or the rate of return to be earned by KfW with
respect to any Loan is reduced, or KfW is required to make any payment in
connection with any transactions contemplated hereby, by or in an amount
reasonably deemed by KfW to be material, then the Borrower will on demand by KfW
from time to time pay KfW such additional amount or amounts as (in the good
faith determination of KfW) are necessary to compensate KfW for such increased
cost, reduction or payment; provided that, KfW shall not be entitled to make any
claim for additional costs under this Section 8.01, to the extent any such
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 KfW 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 KfW and not solely to general regulatory guidelines or
requirements imposed on the banking sector generally. Any such demand by KfW
shall be accompanied by a certificate from KfW stating the basis for its demand
and setting forth in reasonable detail the calculations of the amount thereof.

          8.02 Alternative Interest Rate. If, with respect to any Interest
Period for any Floating Rate Loan or with respect to any Default Interest
Period, KfW determines in its reasonable judgment that quotations of interest
rates of the types referred to in clause (a) in the

                               KfW Loan Agreement

<PAGE>

                                      -12-


definition of "Applicable Base Rate" are not being provided in the relevant
amounts or for the relevant maturity for purposes of determining the "Applicable
Base Rate" for such Interest Period or Default Interest Period, KfW shall
promptly give notice thereof to the Borrower, and the following provisions shall
apply:

          (a) During the thirty-day period following the date of any such notice
     (the "Negotiation Period"), KfW 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 such Loan from time to time and if, at the expiration of the
     Negotiation Period, KfW 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, if
     agreed, such retroactive date) as KfW and the Borrower may in such
     circumstance agree.

          (b) If at the expiration of the Negotiation Period, a Substitute Basis
     shall not have been agreed upon or any required governmental approvals
     therefor shall not have been obtained, KfW shall notify the Borrower of the
     cost to KfW (as reasonably determined by it) of funding and maintaining the
     outstanding affected Loan for such Interest Period or Default Interest
     Period, and the interest payable to KfW on such Loan for such Interest
     Period or Default Interest Period shall be interest at a rate per annum
     equal to the cost of funding and maintaining such Loan as so notified by
     KfW plus the applicable Margin (and, as appropriate, 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 KfW notifies the Borrower that the condition referred to in the first
sentence of this Section 8.02 no longer exists (which notice KfW agrees to give
promptly following the cessation of such condition) or until each affected
Floating Rate Loan is converted into a Fixed Rate Loan pursuant to Section 2.04
hereof, whereupon interest on such Loan shall again be determined in accordance
with the provisions of Section 3.02 hereof, effective commencing on the first
Payment Date next succeeding the date of such notice or (if a Fixed Rate Period
is so established) the first day of such Fixed Rate Period.

          8.03 Mitigation. If an event or circumstance occurs that would entitle
KfW to exercise any of the rights or benefits afforded by this Article VIII,
KfW, promptly upon becoming aware of the same, shall take such steps as may be
reasonably available to it to eliminate or mitigate the effects of such event or
circumstance; provided, however, that KfW shall not be under any obligation to
take any steps that, in its sole discretion, would (a) result in its incurring
additional costs or taxes or (b) otherwise be disadvantageous to KfW.

                                   ARTICLE IX

                              CONDITIONS OF LENDING

          9.01 Initial Loan. The obligation of KfW to make the initial Loan to
be made by it hereunder is subject to the satisfaction (or waiver by KfW) of the
following conditions:

                               KfW Loan Agreement

<PAGE>

                                      -13-


          (a) Satisfaction of Common Conditions Precedent. The common conditions
     precedent to the initial disbursement of the Senior Facility Loans set
     forth in Section 5.01 of the Master Participation Agreement shall have been
     satisfied (or waived as provided therein).

          (b) HERMES Guarantee. The HERMES Guarantee shall have been issued,
     shall be the legal, valid and binding obligation of HERMES (acting in its
     capacity as an agent of the government of the Federal Republic of Germany),
     shall be in full force and effect, shall have been duly registered with the
     relevant governmental or other authorities and all relevant fees and
     charges relating thereto which are then due and payable shall have been
     paid in full.

          (c) Export Contracts. The Export Contracts shall not have been
     cancelled, rescinded or terminated for reasons other than performance of
     their terms.

          (d) No modifications of Export Contracts. No modification of, or
     amendment to, the Export Contracts that will (i) reduce the total price of
     the Export Contracts below US$22,500,000 or (ii) change the Exporter under
     the Export Contracts, in each case without the prior consent of KfW.

          (e) Drawdown Certificate. Not less than 15 Business Days prior to the
     proposed date of borrowing, KfW shall have received a KfW Loan Agreement
     Drawdown Certificate in substantially the form set forth in Exhibit C
     hereof (a "Drawdown Certificate"), duly completed and executed by the
     Borrower and the Borrower shall have provided the Trustee and the
     Administrative Agent with a copy of such Drawdown Certificate.

          9.02 Additional Conditions. The obligation of KfW to make each Loan
(excluding the initial Loan which is subject to the conditions described in
Section 9.01 above) hereunder is subject to the further 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);

          (b) Drawdown Certificate. Not less than 15 Business Days prior to the
     proposed date of borrowing KfW shall have received a KfW Loan Agreement
     Drawdown Certificate in substantially the form set forth in Exhibit C
     hereof (a "Drawdown Certificate"), duly completed and executed by the
     Borrower and the Borrower shall have provided the Trustee and the
     Administrative Agent with a copy of such Drawdown Certificate; and

          (c) HERMES Guarantee. The HERMES Guarantee shall not have been
     revoked, canceled, restricted or suspended, unless such revocation,
     cancellation, restriction or suspension was directly and proximately caused
     by (i) the failure of KfW to pay any applicable guarantee fee after the
     Borrower has paid to KfW all amounts demanded in respect thereof pursuant
     to Section 4.03 hereof when due or

                               KfW Loan Agreement

<PAGE>

                                      -14-


     (ii) misrepresentations by KfW to HERMES unless such misrepresentations
     were based upon information supplied to KfW in writing by the Borrower or
     the Parent Companies.

                                    ARTICLE X

                                    COVENANTS

          The Borrower has undertaken certain covenants as set forth in Article
VII of the Master Participation Agreement. The rights of KfW in respect of such
covenants are set forth in the Master Participation Agreement and Master
Security Agreement. The Borrower further covenants and agrees with KfW that it
shall use the loan proceeds solely in accordance with the terms of Section 2.01
hereof.

                                   ARTICLE XI

                         REPRESENTATIONS AND WARRANTIES

          The Borrower has given certain representations and warranties in
Article VI of the Master Participation Agreement. The rights of KfW in respect
of such representations and warranties are set forth in the Master Participation
Agreement and Master Security Agreement.

                                   ARTICLE XII

                           EVENTS OF DEFAULT; REMEDIES

          12.01 Events of Default. Subject to Section 12.02, each of the MPA
Events of Default set forth in Section 9.01 of the Master Participation
Agreement is hereby incorporated by reference in this Agreement as if fully set
forth herein, in accordance with their terms, unless waived in accordance with
the Master participation Agreement.

          12.02 Remedies. Upon the occurrence and Continuance of an MPA Event of
Default, KfW shall only 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.

          12.03 Suspension, Cancellation or Termination of Commitment. In the
event that HERMES revokes, cancels, restricts or suspends the HERMES Guarantee
(other than by reason of improper acts or inactions on the part of KfW) then (i)
KfW shall have the right to suspend, cancel or terminate its Aggregate Committed
Amount, (ii) KfW shall not be required to disburse or fund any additional Loans
and (iii) the provisions of Section 3.10 of the Master Participation Agreement
shall apply.

                                  ARTICLE XIII

                                  MISCELLANEOUS

          13.01 No Waiver. No failure on the part of KfW to exercise, and no
delay in exercising, and no course of dealing with respect to, any right, power
or privilege under this Agreement or the Promissory Notes shall operate as a
waiver thereof; nor shall any single or partial exercise of any right, power or
privilege under this Agreement or the Promissory Notes

                               KfW Loan Agreement

<PAGE>

                                      -15-


preclude any other or further exercise thereof or the exercise of any other
right, power or privilege. Except as expressly provided herein and in the Master
Participation Agreement, the remedies provided herein are cumulative and not
exclusive of any remedies provided by law.

          13.02 No Immunity. To the extent that any party hereto has or
hereafter may acquire any immunity from any court or from jurisdiction of 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.

          13.03 Jurisdiction and Service of Process. 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 process pursuant to Section 12.16(b) of the Master Participation
Agreement.

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

          13.05 Assignments and Participations; Information.

          (a) The Borrower may not assign its rights or obligations hereunder or
under the Promissory Notes without the prior consent of KfW.

          (b) KfW may at any time transfer the Loans, the Promissory Notes and
Commitments to a wholly-owned subsidiary of KfW whose jurisdiction is Germany,
and in the event of such transfer all references herein to "KfW" shall be deemed
to such wholly-owned subsidiary.

          (c) KfW may at any time sell, assign, transfer, grant participations
in, or otherwise dispose of a portion of the Loans, the Promissory Notes or the
Commitment (collectively, "Transferred Interests") (i) to any other Person
subject to Section 12.13 of the Master Participation Agreement or (ii) if an MPA
Event of Default has occurred and is continuing, to HERMES or any agency,
instrumentality or political subdivision of Germany (for purposes of this
Section 13.05, collectively, "HERMES" and, together with any transferee in
accordance with clause (i) of this Section 13.05(c), "Transferees"). Upon the
execution and delivery by any Transferee to the Borrower of an instrument in
writing pursuant to which such Transferee agrees to assume the obligations of
KfW hereunder with respect to the Transferred Interest, such Transfer will be
effective and such Transferee may exercise all legal and equitable rights and
remedies, and shall be entitled to the benefits of Article VII hereof, as if
such Transferee were a lender hereunder holding a "Loan" in the amount of the
Transferred Interest held by it.

          (d) KfW may furnish any information concerning the Borrower in the
possession of KfW from time to time to Transferees (including prospective
Transferees) subject

                               KfW Loan Agreement

<PAGE>

                                      -16-


to the confidentiality provisions contained in Section 12.10 of the Master
Participation Agreement.

          (e) Notwithstanding anything in the Master Participation Agreement to
the contrary, KfW shall be entitled as and when required or requested by HERMES
to give information to the representatives of HERMES and international
organizations entrusted with the collection of statistical data, particularly in
connection with debt servicing, in connection with the implementation of this
Agreement.

          (f) Except as otherwise expressly provided in this Agreement, this
Agreement is legally independent of all Export Contracts. In connection with the
performance of its obligations under this Agreement, the Borrower may in no
event raise objections on the basis of the Export Contracts for which the
financing is in part provided or any other contract providing for the export of
goods or services.

          13.06 Amendments, Etc. Subject to Article X of the Master
Participation Agreement, the provisions of this Agreement may not be amended,
modified or waived except by an instrument or instruments in writing or by
facsimile transmission signed by the Borrower and KfW.

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

          13.08 Judgment Currency. This is an international loan transaction in
which the specification of Dollars and payment in New York, New York, U.S. is of
the essence, and Dollars shall be the currency of account in all events. The
obligations of the Borrower to make payments hereunder shall not be discharged
by an amount paid in any currency other than Dollars, whether pursuant to a
court or arbitral judgment or otherwise, to the extent that the amount so paid
upon conversion to Dollars and transferred to New York, New York under normal
banking procedures does not yield the amount of Dollars due, and the Borrower
hereby, as a separate obligation and notwithstanding any such judgment, agrees
to indemnify the Trustee, the Appointed Parties' Agents and each Senior Facility
Lender against, and to pay to the Trustee, the Appointed Parties' Agents and
each Senior Facility Lender on demand, in Dollars, any difference between the
sum originally due in Dollars and the amount of Dollars received upon any such
conversion and transfer. The provisions of Section 12.06 of the Master
Participation Agreement shall be deemed incorporated herein in their entirety.

          13.09 Successors and Assigns. This Agreement shall be binding upon and
inure to the benefit of the Borrower and KfW and their respective permitted
successors and assigns.

          13.10 Stamp Taxes. The Borrower agrees to pay all stamp and other
duties or taxes imposed by any taxing authority of or in Peru on this Agreement,
the Loans or the Promissory Notes, or on the enforcement of any thereof or of
any rights under any thereof, or on the introduction of any thereof before any
court or other authority, and shall indemnify KfW against all liabilities,
costs, claims and expenses resulting from any failure to pay or delay in paying
any such duty or tax.

                               KfW Loan Agreement

<PAGE>

                                      -17-


          13.11 Survival. Without limitation, the obligations of the Borrower
under Sections 6.03, 8.01 and 13.10 hereof and Sections 3.09 and 3.11 of the
Master Participation Agreement and the obligations of KfW under Section 3.09 of
the Master Participation Agreement shall survive the repayment of the Loans and
the cancellation of the Promissory Notes.

          13.12 Severability. Any provision hereof 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 or affecting the validity or enforceability of such
provision in any other jurisdiction. Any gap resulting as a consequence of any
such invalidity shall be filled by a provision consistent with the purpose of
this Agreement.

          13.13 WAIVER OF JURY TRIAL. EACH OF THE BORROWER AND KfW 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 PROMISSORY NOTES OR THE TRANSACTIONS
CONTEMPLATED HEREBY WHETHER BASED ON CONTRACT, TORT OR OTHER THEORY.

          13.14 Notices. The provisions of Section 12.11 of the Master
Participation Agreement shall be deemed incorporated herein in its entirety.
Except as otherwise provided in this Agreement, all such communications shall be
deemed to have been duly given when transmitted by telecopier and received or
personally delivered or, in the case of a mailed notice, upon receipt, in each
case given or addressed as aforesaid.

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

          13.16 No Restriction. Nothing herein shall in any way limit the
Borrower's ability to seek damages from Exporter under any of the Export
Contracts if the goods delivered pursuant to the Export Contract do not meet
contract specifications set forth under such Export Contract.

                               KfW Loan Agreement

<PAGE>

          IN WITNESS WHEREOF, the parties hereto have caused this Agreement to
be duly executed.

                                        SOCIEDAD MINERA CERRO VERDE S.A.A.


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

                               KfW Loan Agreement

<PAGE>

                                        KFW


                                        By: /s/ Wolfgang Behler
                                            ------------------------------------
                                        Name: Wolfgang Behler
                                        Title: First Vice President


                                        By: /s/ Stephan Pueschel
                                            ------------------------------------
                                        Name: Stephan Pueschel
                                        Title: Senior Project Manager

                               KfW Loan Agreement

<PAGE>

                                                                       EXHIBIT A
                                                           to KfW Loan Agreement

                              AMORTIZATION SCHEDULE

<TABLE>
<CAPTION>
             % of the aggregate amounts
Repayment   of all Advances made by KfW
  Number            to 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>

                               KfW Loan Agreement

<PAGE>

                                                                       EXHIBIT B
                                                           to KfW 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
    PAYMENT DATE         TO BE 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>

          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

                               KfW Loan Agreement

<PAGE>

                                      -2-


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.

          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 be due and unpaid, at an annual rate equal to the 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$____________).

          If Borrower prepays all or part of the outstanding principal amount
hereof [on a date other than the last day of the then current Interest
Period](2), the Borrower shall pay to the Holder [(a) a prepayment commission
equal to the Present Value of the excess (if any) of (i) the sum of the interest
payments which (in the absence of such prepayment) would have been payable on
each installment hereof (or portion thereof) so prepaid, on each Payment Date
from the date of such prepayment to the original scheduled maturity date of such
installment, at the Base Rate over (ii) the sum of the interest payments which
would be received if the principal amount of each installment hereof (or portion
thereof) so prepaid were re-invested, for the period from the date of such
prepayment to the original scheduled maturity date hereunder of such
installment, at the Reinvestment Rate (as defined below), and (b)](3)
reimbursement of its funding losses or expenses (if any) related to such
prepayment; provided that, if the Borrower makes a voluntary prepayment of all
or any portion of the principal outstanding amount hereof with the proceeds of
replacement debt obtained (either at the time or within a period of one year
from the date of such voluntary prepayment) from a person other than the Parent
Companies or an Affiliate of the Parent Companies, the Borrower shall, as of the
date that such replacement debt is obtained, pay to the Holder a prepayment fee
equal to 0.5% of the aggregate principal amount prepaid and provided further
that if the Holder suspends, cancels or terminates its commitments to lend to
the Borrower under the credit facility, as contemplated in Section 12.03 of the
Loan Agreement, the Borrower may prepay all or any portion of the outstanding
amount hereof without prepayment premium or penalty of any kind whatsoever.

          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

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

(2)  Include this bracketed language only for Floating Rate Loans.

(3)  Include this bracketed language only for Fixed Rate Loans.

                               KfW Loan Agreement

<PAGE>

                                      -3-


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.

          "Affiliate" means, with respect to any Person (the "First Person"),
any other Person (the "Second Person") which directly or indirectly Controls, or
is under common Control with, or is Controlled by, such First Person.

          "Applicable Margin" means 0.35% per annum.

          "Base Rate" means, for any Interest Period or Default Interest Period
therefor, [the interest rate per annum for dollar deposits for a period equal to
(or, if there is no equal, then most comparable to) such Interest Period or
Default Interest Period which appears on Reuters Screen LIBOR01 Page (or such
other page as may replace that page on that service for the purpose of
displaying the British Bankers Association Interest Settlement Rate) at or about
11:00 a.m. London time on the date two Eurodollar Business Days prior to the
first day of such Interest Period or Default Interest Period; provided that, if
no such rate appears on Reuters Screen LIBOR01 Page (or such other page as may
replace that page on that service for the purpose of displaying the British
Bankers Association Interest Settlement Rate) for any relevant Interest Period
or Default Interest Period, the Base Rate shall mean for each Loan during such
Interest Period or Default Interest Period the rate per annum determined by the
Holder which appears on the page designated Page 3750 on the Moneyline Telerate
Inc. at or about 11:00 a.m. London time on the date two Eurodollar Business Days
prior to the first day of such Interest Period or Default Interest Period](4)

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

----------
(4)  Insert (i) this bracketed language for Floating Rate Loans or (ii) the
     Fixed Rate calculated in accordance with clause (b) of the definition of
     Applicable Base Rate.

                               KfW Loan Agreement

<PAGE>

                                      -4-


          "Control" (including, with its correlative meanings "Controlled by"
and "under common Control with") means possession, directly or indirectly, of
power (whether or not exercised) to direct or cause the direction of or exercise
a controlling influence on management or policies (whether through legal or
beneficial ownership of securities or partnership or other ownership interests,
by contract, representation on the board of directors or similar governing body
or otherwise).

          "Default Interest Period" means each successive period (not in excess
of six months) while any amount payable by the Borrower hereunder is in default,
as the Holder shall choose in its sole discretion, the first such period to
commence as of the date on which such amount in default becomes due and each
succeeding such period to commence immediately upon the expiry of the
immediately preceding such period.

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

          "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

                               KfW Loan Agreement

<PAGE>

                                      -5-


               (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 between the Borrower and KfW.

          "MPA" means the Master Participation 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, 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.

          "Parent Companies" means, collectively, Phelps Dodge Corporation,
Sumitomo Metal Mining Co. Ltd., Sumitomo Corporation and Compania de Minas
Buenaventura S.A.A.

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

          "Present Value" of any amount receivable or deemed receivable on a
specified future date, means such amount discounted to present value (from such
specified future date to the date of such prepayment) at the Reinvestment Rate.

          "Reinvestment Rate" means, in respect of each installment of principal
prepaid, the rate which appears on the Reuters Screen RTRTSY1 Page at or about
4:00 p.m. (Frankfurt time) on a date selected by the Holder occurring on or
within five Eurodollar Business Days prior to the date of such prepayment, for
actively traded U.S. Treasury obligations having substantially the same
scheduled maturity as such installment (interpolating, where appropriate,
between the yield to maturity quotations for the next shorter and next longer
maturities for any Loan installment scheduled to mature at a time for which no
such yield quotation is expressed).

          "Reuters Screen LIBOR01 Page" shall mean the display page so
designated on the Reuter Monitor Money Rates Service (or such other page as may
replace that page on that service for the purpose of displaying London interbank
offered rates for Dollar deposits).

          "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.

                               KfW Loan Agreement

<PAGE>

                                      -6-


          "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 and in immediately available
funds, without set-off, counterclaim or reduction for any reason whatsoever, by
credit to an account designated by the Holder at Citibank in New York, New York
(Swift Code: BIC CITIUS33, Account number: 10926093, Account name: KfW) and
designating the KfW in Frankfurt am Main, Germany as the beneficiary (Swift
Code: KFWIDEE, Payment Reference: yyyymmdd/Cerro Verde (8137091719), not later
than 11:00 a.m. New York City time on the date on which such payment shall
become due.

          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 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.

                               KfW Loan Agreement

<PAGE>

                                      -7-


          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 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

                               KfW Loan Agreement

<PAGE>

                                                                       EXHIBIT C

                                                           to KfW Loan Agreement

                         [Form of Drawdown Certificate]

To:   KfW IPEX-Bank
      Postfach 11 11 41
      D-60 046 Frankfurt/Main
From: SOCIEDAD MINERA CERRO VERDE S.A.A.
                                                            Date: ______________

                               KFW LOAN AGREEMENT
                             Request for drawing no.

X1a1 - Loan No. [____________]
       dated as of [____________]
                for US$[____________]

1.   The Borrower hereby requests a [Floating Rate / Fixed Rate] Loan under the
     KfW Loan Agreement in US$ as follows:

     (a) Drawdown Date: _____________

     (b) Amount: US$_____________

2.   The Amount in paragraph 1(b) is made up of:

     (a)  US$ in respect of German goods and services supplied by Polysius AG;
          and/or

     [(b) US$ in respect of the Facility Fee charged by HERMES for the HERMES
          Guarantee](5)

3.   The Borrower confirms that:

     (a)  the representation and warranties contained in Article VI of the
          Master Participation Agreement shall be true and correct in all
          material respects as of the date of the initial disbursement;

     (b)  no MPA Default has occurred and is Continuing; and

     (c)  each of the other conditions contained in [Section 5.01 [first
          disbursement only], [Section 5.02 [Conditions Precedent for subsequent
          disbursements only] of the Master Participation Agreement and [Section
          9.01 [initial disbursement only], [Section 9.02 [Conditions Precedent
          for subsequent disbursements only] of the KfW Loan Agreement is
          satisfied on the date of this Request or is expected to be satisfied
          immediately after the disbursement is made (as applicable).

4.   The Borrower confirms that the aggregate amount borrowed under the KfW Loan
     Agreement does not exceed 85% of the aggregate amounts of the purchase
     orders placed to date under the Export Contracts plus the amounts borrowed
     to finance the Facility Fee.

5.   The Borrower requests that the amount mentioned under paragraph 1(b) above
     be paid to the Onshore Dollars Account.

6.   Terms defined in the KfW Loan Agreement shall bear the same meanings when
     used in this Request.

----------
(5)  [Only applies to disbursement of the initial Advance and shall include 100%
     of the Facility Fee.]

                               KfW Loan Agreement

<PAGE>

                                       -2-


                                        BORROWER


                                        By:
                                            ------------------------------------
                                        Authorized Signatory

                               KfW Loan Agreement