Metallica Resources Inc. - Exhibit 4.16 - Prepared By TNT Filings Inc.




 



Exhibit 4.16 

AMENDMENT AGREEMENT TO THE PROFESSIONAL
SERVICES CONTRACT, ENTERED INTO BY AND BETWEEN THE COMPANY "MINERA SAN XAVIER,
S.A. DE C.V.", REPRESENTED BY MR. SERGIO ENRIQUE LOPEZ BRIONES (HEREINAFTER
REFERRED TO AS "MSX") AND BY THE COMPANY "FIREX, S.A. DE C.V.", REPRESENTED BY
MR. JORGE MENDIZABAL ACEBO (HEREINAFTER REFERRED TO AS "FIREX"), ACCORDING TO
THE FOLLOWING ANTECEDENTS, REPRESENTATIONS AND CLAUSES. 

A N T E C E D E N T S 

[English Translation of Spanish Language
Document] 


FIRST.- On October 25th, 2004, MSX and FIREX
entered into a professional services contract, by which the latter committed to
assist the first, during the development of the mining project of Cerro de San
Pedro, located in the Municipality of the same name, for which Mr. Jorge
Mendizabal Acebo was appointed as advisor, acting as General Director of such
project. The term of effectiveness originally agreed for such contract was of
six (6) months. 

SECOND.- Since it represents a benefit for
MSX, this has agreed with its counterpart, to modify the term of effectiveness
of such contract, reason that justifies the formalization of the present
amendment agreement. 


R E P R E S E N T A T I O N S 



  I. Of MSX: 

  
    UNIQUE.- To ratify each and all the representations
    established on the contract described in the FIRST antecedent of this
    document. 

  

  II. Of FIREX: 

  
    UNIQUE.- To ratify each and all the representations
    established on the contract described in the FIRST antecedent of this
    document. 

  

  III. Of the parties: 







  
    
    a) To ratify the content of their respective representations manifested in
    this document and to acknowledge the personality and legal capacity to which
    they formalize the same. 

    
    b) To accept regulate the legal relationship that binds them, according to
    the terms, conditions and scope of this amendment agreement, in accordance
    to the content of the same, granting their free will, not existing deceitful
    representations, error, bad faith, nor any other act or omission that would
    induce the parties to enter this agreement that they would not otherwise
    have made; the parties, therefore, agree the following: 

  




C L A U S E 


UNIQUE.- The parties ratify the content and
scope of each and all the clauses container in the professional services
contract, referred to in the FIRST antecedent of this document, with exception
to clauses SECOND and THIRD, which are hereby amended as follows: 



  
    "SECOND.- TERM OF EFFECTIVENESS. The
    present contract shall be effective for an indefinite term, having the
    parties the right to terminate it at any time, by giving its counterpart
    written notice, with at least thirty (30) days of anticipation to the date
    in it wishes to stop the professional services, and provided that the
    professional fees agreed in favor of FIREX, shall be paid until the date in
    which the contract is formally terminated. 

    THIRD.- PROFESSIONAL FEES. MSX shall pay
    FIREX, for the professional services described in clause first, a monthly
    fee equal to US$6,250.00 (six thousand two hundred and fifty dollars 00/100
    USCy) plus the corresponding Added Value Tax, amount that shall be paid in
    Mexican currency at the rate determined by BANXICO on the day on which the
    amount is due and payable." 

  




Having read the parties the present agreement, they sign it in
two (2) copies, in the city of San Luis Potosi, on the 15th day of April, 2005.




	 	 
	By MSX 	By FIREX 
	/s/ Sergio Enrique Lopez
    Briones	/s/ Jorge Mendizabal Acebo
	MR. SERGIO ENRIQUE LOPEZ	MR. JORGE MENDIZABAL ACEBO
	BRIONES	 
	 	 
	 	 
	 	 
	WITNESSES
	 	 
	 	 
	 	 
	/s/ Richard J. Hall	/s/ Jesús Motilla Martinez
	MR. RICHARD J. HALL	MR. JESUS MOTILLA MARTINEZ