Exhibit 10.22        Execution Copy



FOURTH OMNIBUS AMENDMENT AGREEMENT

Among

MINERA
SAN CRISTÓBAL, S.A.,
as Borrower

APEX
SILVER MINES LIMITED,

APEX
SILVER MINES SWEDEN AB,

APEX
LUXEMBOURG S.A. R.L.,

APEX
SILVER FINANCE LTD.,

APEX
METALS MARKETING GmbH,

SUMITOMO
CORPORATION,

SC
MINERALS AKTIEBOLAG,

COMERCIAL
METALES BLANCOS AB,

BNP
PARIBAS,
as Administrative Agent

BARCLAYS
CAPITAL,
as Technical Agent

CORPORACIÓN
ANDINA DE FOMENTO,
as a Senior Lender

JPMORGAN
CHASE BANK, N.A.,
as Collateral Agent and Securities Intermediary,

THE
SENIOR LENDERS PARTY HERETO

and

THE
HEDGE BANKS PARTY HERETO

Dated
as of December 12, 2008



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TABLE OF CONTENTS

PageARTICLE I DEFINITIONS

2Section 1.01.

Defined Terms

2Section 1.02.

Interpretation

2ARTICLE II REPRESENTATIONS AND WARRANTIES

2Section 2.01.

Authority

2Section 2.02.

Consents and Approvals

2Section 2.03.

No Conflicts

2ARTICLE III SECURED PARTY CONSENTS AND APPROVALS

2Section 3.01.

Consents and Approvals

2Section 3.02.

Additional Hedge Collateral

3ARTICLE IV AMENDMENTS

3Section 4.01.

Financing Documents

3ARTICLE V MISCELLANEOUS

3Section 5.01.

Counterparts

3Section 5.02.

Severability

4Section 5.03.

Governing Law

4Section 5.04.

Headings

4Section 5.05.

Waivers; Amendment

4Section 5.06.

Limited Agreement

4Section 5.07.

Authorizations

4APPENDIX A

Form of Lender Term SheetAPPENDIX B

Form of Termination, Release and Settlement Agreement (with Barclays Capital)APPENDIX C

Form of Termination, Release and Settlement Agreement (with BNP Paribas)


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ThisFOURTH OMNIBUS AMENDMENT AGREEMENT(this "Agreement"), dated as of
December 12, 2008, is entered into amongMINERA SAN CRISTÓBAL, S.A., asociedad
anónimaorganized under the laws of Bolivia (the "Borrower"),APEX SILVER MINES
LIMITED, an exempted company duly incorporated with limited liability and validly existing under the laws of the Cayman Islands
("ASM"),APEX SILVER MINES SWEDEN AB, aprivat
aktiebolagorganized under the laws of Sweden ("Apex Sweden"),APEX LUXEMBOURG S.A.
R.L., asociété à responsabilité limitéeorganized
under the laws of Luxembourg ("Apex Luxembourg"),APEX SILVER FINANCE LTD., an exempted company
duly incorporated with limited liability and validly existing under the laws of the Cayman Islands ("Apex Silver Finance"),APEX
METALS MARKETING GmbH, a company with limited liability organized under the laws of Switzerland ("Apex Metals
Marketing"),SUMITOMO CORPORATION, a corporation organized under the laws of Japan
("Sumitomo"),SC MINERALS AKTIEBOLAG, a privat aktiebolag organized under the laws of Sweden
("SC Minerals Sweden"),COMERCIAL METALES BLANCOS AB, a privat aktiebolag organized under the laws of
Sweden ("Comercial Metales Blancos"),BNP PARIBAS, a banking institution organized under the laws of
France, as Administrative Agent for the Secured Parties (the "Administrative Agent"),BARCLAYS CAPITAL,
a division of Barclays Bank PLC, a public limited company organized under the laws of England and Wales, as Technical Agent (the "Technical
Agent"),CORPORACIÓN ANDINA DE FOMENTO, a multilateral institution organized and existing pursuant to its
Constitutive Agreement signed in Bogotá, Colombia on February 7, 1968, as a Senior Lender,JPMORGAN CHASE BANK, N.A., a national
banking corporation as Collateral Agent (the "Collateral Agent") and as Securities Intermediary (the "Securities
Intermediary"), theSENIOR LENDERSparty hereto and theHEDGE BANKSparty
hereto.

RECITALS

WHEREAS, the Borrower, Apex Sweden, Apex Metals Marketing, Apex Luxembourg, Apex Silver Finance, SC Minerals Sweden, Comercial Metales
Blancos, the Administrative Agent, the Technical Agent, Corporación Andina de Fomento, the Collateral Agent, the Securities Intermediary, the Senior Lenders party thereto and the Hedge
Banks party thereto are parties to the Common Security Agreement, dated as of December 1, 2005 (as amended and supplemented from time to time, the "Common Security
Agreement");

WHEREAS,
pursuant to the Common Security Agreement and the other Transaction Documents, the Borrower and the other parties thereto agreed, among other things, to the terms and conditions
for the financing of the Project;

WHEREAS,
the Borrower, the Sponsors and the Secured Parties have agreed on binding terms and conditions for the restructuring of the financing of the Project, as set forth in that
certain term sheet dated December 12, 2008 (the "Lender Term Sheet"), the form of which is attached as Appendix A;

WHEREAS,
in anticipation of consummating such restructuring, the Borrower, Apex Silver Finance and the Hedge Banks wish to terminate all Mandatory Metals Hedge Agreements and all
Mandatory Metals Hedge Transactions, and provide that no Mandatory Metals Hedge Agreement or Mandatory Metals Hedge Transaction shall hereafter be required by the Secured Parties, or otherwise
required to be executed, maintained or pledged as collateral pursuant to any Transaction Document;

WHEREAS,
the Secured Parties are willing to approve such transactions and changes upon the terms and conditions set forth herein;

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NOW,
THEREFORE, in consideration of the mutual agreements herein contained and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the
parties hereto hereby agree as follows:

ARTICLE I        DEFINITIONS

Section
1.01.Defined Terms.Except as otherwise defined herein, capitalized terms used in this Agreement shall
have the meanings given thereto in the Common Security Agreement (including Appendix A thereto). As used in this Agreement, "Hedge Termination
Documents" means this Agreement, the Lender Term Sheet, the Termination, Release and Settlement Agreement among Barclays Capital and the other parties thereto (in the form
attached hereto asAppendix B), and the Termination, Release and Settlement Agreement among BNP Paribas and the other parties thereto (in the
form attached hereto asAppendix C).

Section
1.02.Interpretation.The rules of interpretation set forth in clauses (a) to (j) of
Section 1.02 of the Common Security Agreement shall apply, with necessary changes, to this Agreement as if set forth in full in this Section 1.02.

ARTICLE II        REPRESENTATIONS AND WARRANTIES

Each of the Borrower, ASM, Apex Sweden, Apex Luxembourg, Apex Silver Finance, Apex Metals Marketing, Sumitomo, SC Minerals Sweden and
Comercial Metales Blancos represents and warrants to the Administrative Agent and the Collateral Agent for the benefit of the Secured Parties that:

Section
2.01.Authority.It has all requisite organizational power and authority to enter into each Hedge
Termination Document to which it is a party and to incur and perform its obligations provided for herein and therein.

Section
2.02.Consents and Approvals.All Authorizations and Government Approvals which are necessary for
(i) the execution and delivery by it of this Agreement and the other Hedge Termination Documents to which it is a party and (ii) the performance of its obligations hereunder and
thereunder have been obtained and are in full force and effect.

Section
2.03.No Conflicts.The execution, delivery and performance by it of each of the Hedge Termination
Documents to which it is a party and the consummation of the transactions contemplated thereby do not and will not (i) violate any provision of its Organizational Documents, any Authorization,
any Government Rule or any Government Approval applicable to it; (ii) conflict with, result in a breach of or constitute a default under any indenture or loan or credit agreement to which it is
a party or by which it or its property may be bound or affected in any material respect; or (iii) result in, or create any
Lien (other than Liens specifically permitted under the Financing Documents) upon or with respect to any of the properties now owned or hereafter acquired by it.

ARTICLE III        SECURED PARTY CONSENTS AND APPROVALS

Section
3.01.Consents and Approvals.Subject only to execution of (i) this Agreement by all the parties
named on the signature pages hereof and (ii) the other Hedge Termination Documents by all the parties named on the signature pages thereof, the Secured Parties consent (effective as of the date
hereof) to:

(a)   the
amendments set forth in Article IV;

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(b)   the
termination of all Mandatory Metals Hedge Agreements and all Mandatory Metals Hedge Transactions;

(c)   the
release of all Apex Silver Finance Collateral (as defined in the Apex Silver Finance Cross-Guarantee and Security Agreement) and the termination of all security
interests created by the Apex Silver Finance Cross-Guarantee and Security Agreement; and

(d)   the
release of all Mandatory Metals Hedge Agreements and Mandatory Metals Hedge Transactions (including all claims resulting from any failure or performance or
compliance with any of the provisions of the Mandatory Metals Hedge Agreements) otherwise constituting Collateral for purposes of the Common Security Agreement or any other Financing Document,
including pursuant to Section 3.02(g) of the Common Security Agreement, and the termination of all security interests created by any Security Document to the extent affecting such Collateral.

Section
3.02.Additional Hedge Collateral.Subject only to execution of (i) this Agreement by all the
parties named on the signature pages hereof and (ii) the other Hedge Termination Documents by all the parties named on the signature pages thereof, the Hedge Banks consent (as of the date
hereof) to: (a) the termination of the Sumitomo Hedge Guarantees, and the Sumitomo Hedge Guarantees shall thereupon immediately terminate and Sumitomo shall be released from all liabilities and
obligations thereunder; (b) the termination of the Hedge Guaranty, and the Hedge Guaranty shall thereupon immediately terminate and MSC shall be released from all liabilities and obligations
thereunder; and (c) the termination of the ASM Cash Collateral Agreements and the release to ASM of any unreleased cash collateral provided by ASM thereunder to the extent such cash collateral
is not otherwise required to be applied to the final settlement of the Mandatory Metals Hedge Transactions in accordance with the Hedge Termination Documents.

ARTICLE IV        AMENDMENTS

Section
4.01.Financing Documents.Subject to Article III and effective as of the date hereof, the
Secured Parties: (a) acknowledge and agree that no Mandatory Metals Hedge Agreement or Mandatory Metals Hedge Transaction shall hereafter be required by the Secured Parties, or otherwise
required to be executed, maintained or pledged as collateral pursuant to any Transaction Document; (b) irrevocably and permanently waive any obligation of the Borrower, ASM, Apex Sweden, Apex
Luxembourg, Apex Silver Finance, Apex Metals Marketing, Sumitomo, SC Minerals Sweden and Comercial Metales Blancos in respect of any Mandatory Metals Hedge Agreement or Mandatory Metals Hedge
Transaction, arising from, under, or pursuant to, any Financing Document; (c) acknowledge and agree in furtherance of the foregoing, that each and every reference to any Mandatory Metals Hedge
Agreement or Mandatory Metals Hedge Transaction, and any obligation in respect thereof, set forth in any Financing Document shall be deleted from such Financing Document; and (d) acknowledge
and agree that each Hedge Bank shall have no obligation to share its Final Settlement Amount (as defined in the Termination, Release And Settlement Agreement to which such Hedge Bank is a party),
which amounts shall not be subject to Section 14.07(a) of the Common Security Agreement, and that each Hedge Bank shall cease to be a party (in such capacity) to the Common Security Agreement
and any other Financing Document.

ARTICLE V    MISCELLANEOUS

Section
5.01.Counterparts.This Agreement may be executed in any number of counterparts and by different
parties hereto on separate counterparts, each of which shall constitute an original, but all of which when taken together shall constitute one and the same instrument. Delivery of an executed

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counterpart
of a signature page to this Agreement by fax shall be effective as delivery of a manually executed counterpart of this Agreement.

Section
5.02.Severability.Any provision of this Agreement held to be invalid, illegal or unenforceable in any
jurisdiction shall, as to such jurisdiction, be ineffective to the extent of such invalidity, illegality or unenforceability without affecting the validity, legality and enforceability of the
remaining provisions hereof; and the invalidity of a particular provision in a particular jurisdiction shall not invalidate such provision in any other jurisdiction.

Section
5.03.Governing Law.This Agreement shall be governed by and construed in accordance with the laws of
the State of New York.

Section
5.04.Headings.Article and Section headings and the Table of Contents used herein are for convenience
of reference only, are not part of this Agreement and shall not affect the construction of, or be taken into consideration in interpreting, this Agreement.

Section
5.05.Waivers; Amendment.None of the terms or provisions of this Agreement may be waived, amended,
supplemented or otherwise modified without the consent of each of the parties hereto.

Section
5.06.Limited Agreement.The amendments, waivers and consents set forth in this Agreement are limited in
effect, shall apply only as expressly set forth herein and shall not constitute or be deemed to be an amendment or waiver of any other provision of, or a consent to any action limited by, any
Financing Document, each of which shall remain in full force and effect and are hereby ratified and confirmed in all respects.

Section
5.07.Authorizations.Each of the Senior Lenders and Hedge Banks hereby authorizes the Administrative
Agent, the Collateral Agent and the Technical Agent to execute and deliver this Agreement and each of the agreements substantially in the forms attached hereto to which they are required to be a
party.

[The remainder of this page intentionally left blank]

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IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be duly executed by their respective authorized officers as the day and year first above written.

MINERA SAN CRISTÓBAL, S.A.By:

/s/ Jeffrey G. Clevenger Name:  Jeffrey G. Clevenger
Title:  President and DirectorAPEX SILVER MINES LIMITEDBy:

/s/ Jeffrey G. Clevenger Name:  Jeffrey G. Clevenger
Title:  President and Executive OfficerAPEX SILVER MINES SWEDEN ABBy:

/s/ Gerald J. Malys Name:  Gerald J. Malys
Title:  Deputy Director


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APEX LUXEMBOURG S.A. R.L.By:

/s/ Gerald J. Malys Name:  Gerald J. Malys
Title:  ManagerAPEX SILVER FINANCE LTD.By:

/s/ Robert P. Vogels Name:  Robert P. Vogels
Title:  Vice President


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APEX METALS MARKETING GmbHBy:

/s/ Robert P. Vogels Name:  Robert P. Vogels
Title:  Vice PresidentSUMITOMO CORPORATIONBy:

/s/ Akira Takeuchi Name:  Akira Takeuchi
Title:  Corporate OfficerSC MINERALS AKTIEBOLAGBy:

/s/ Akira Takeuchi Name:  Akira Takeuchi
Title:  Director and Chairman of the BoardCOMERCIAL METALES BLANCOS ABBy:

/s/ Akira Takeuchi Name:  Akira Takeuchi
Title:  Director and Chairman of the Board


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BNP PARIBAS
    as Administrative AgentBy:

/s/ Jeffrey Stufsky Name:  Jeffrey Stufsky
Title:  Managing DirectorBy:

/s/ William Davidson Name:  William Davidson
Title:  Managing DirectorBARCLAYS CAPITAL
    as Technical AgentBy:

/s/ Grant Willis Name:  Grant Willis
Title:  Managing DirectorJPMORGAN CHASE BANK, N.A.,
    as Collateral AgentBy:

/s/ Evangelos Ntavos Name:  Evangelos Ntavos
Title:  Vice PresidentJPMORGAN CHASE BANK, N.A.,
    as Securities IntermediaryBy:

/s/ Evangelos Ntavos Name:  Evangelos Ntavos
Title:  Vice President


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CORPORACIÓN ANDINA DE FOMENTO,
    as a Senior LenderBy:

/s/ Luis Enrique Berrizbeitia Name:    Luis Enrique Berrizbeitia
Title:    Acting Executive PresidentBARCLAYS BANK PLC,
    as a Senior LenderBy:

/s/ Grant Willis Name:  Grant Willis
Title:  Managing DirectorBNP PARIBAS,
    as a Senior LenderBy:

/s/ Jeffrey Stufsky Name:  Jeffrey Stufsky
Title:  Managing DirectorBy:

/s/ William Davidson Name:  William Davidson
Title:  Managing DirectorAUSTRALIA AND NEW ZEALAND BANKING
    GROUP LIMITED, as a Senior LenderBy:

/s/ C. Theodore Wolf Name:  C. Theodore Wolf
Title:  Director, Lending Services


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KFW,
    as a Senior LenderBy:

/s/ Dawko-Schellhaas Name:  Dawko-Schellhaas
Title:  Senior Vice PresidentBy:

/s/ Simone Thrun Name:  Simone Thrun
Title:  SPHNATIXIS, New York Branch,
    as a Senior LenderBy:

/s/ Amit Roy Name:  Amit Roy
Title:  DirectorBy:

/s/ Steven Yoon Name:  Steven Yoon
Title  DirectorCATERPILLAR FINANCIAL SERVICES (UK)
    LTD., as a Senior LenderBy:

/s/ John L. Jones Name:  John L. Jones
Title:  Credit Manager


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N M ROTHSCHILD & SONS LIMITED,
    as a Senior LenderBy:

/s/ Derek McCrone Name:  Derek McCrone
Title:  DirectorBy:

/s/ Nicholas Wood Name:  Nicholas Wood
Title:  DirectorEXPORT DEVELOPMENT CANADA,
    as a Senior LenderBy:

/s/ Arturo Polisena Name:  Arturo Polisena
Title:  Risk Policy ManagerBy:

/s/ H. Clysdale Name:  H. Clysdale
Title:  Sr. CRMFORTIS CAPITAL CORP.,
    as a Senior LenderBy:

/s/ Kerri L. Fox Name:  Kerri L. Fox
Title:  Managing DirectorBy:

/s/ Harry T. Nullet Name:  Harry T. Nullet
Title: Director


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NORDKAP BANK AG,
    as a Senior LenderBy:

/s/ Jeffrey P. Riopelle Name:  Jeffrey P. Riopelle
Title:  SVPBy:

/s/ Simona Kugler Name:  Simona Kugler
Title  Portfolio ManagerFIRSTRAND (IRELAND) PLC,
    as a Senior LenderBy:

/s/ Stephen Peters Name:  Stephen Peters
Title:  Authorised SignatoryBy:

/s/ Emma Brady Name:  Emma Brady
Title:  Authorised Signatory


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BARCLAYS BANK PLC,
  as a Hedge BankBy:

/s/ Grant Willis Name:  Grant Willis
Title:  Managing DirectorBNP PARIBAS,
    as a Hedge BankBy:

/s/ Jeffrey Stufsky Name:  Jeffrey Stufsky
Title:  Managing DirectorBy:

/s/ William Davidson Name:  William Davidson
Title:  Managing Director


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