Offer Update

Antofagasta PLC
20 April 2006


                               

For immediate release


                                 ANTOFAGASTA PLC

            Antofagasta reaches 51.77% interest in Tethyan shares and
                      declares takeover offer unconditional


20 April 2006


Antofagasta PLC ('Antofagasta') is pleased to announce today that it has reached
a relevant interest in Tethyan Copper Company Limited ('Tethyan') shares of
51.77%. Accordingly, Antofagasta's recommended takeover offer for Tethyan has
now been declared unconditional.


The Board of Tethyan unanimously recommends that all shareholders accept the
Antofagasta offer. In addition, Tethyan has confirmed that each of the Tethyan
directors will shortly be accepting the Antofagasta offer for all of the Tethyan
shares they own or control.


Commenting on the offer, Marcelo Awad, CEO of Antofagasta Minerals S.A., stated,
'We believe our offer represents a very attractive price for Tethyan
shareholders and is supported by a unanimous recommendation from the Tethyan
Board. Our offer is now unconditional and scheduled to close on 28 April 2006. I
would therefore encourage all remaining Tethyan shareholders to accept the offer
without delay.'


Antofagasta, through its wholly owned subsidiary Atacama Copper Pty Limited
('Atacama') has also agreed to pay brokers a handling fee for acceptances they
initiate in respect of certain Tethyan shareholders. Further details will be
provided in Atacama's third supplementary bidder's statement to be lodged at the
Australian Stock Exchange today.


Rothschild is advising Antofagasta in relation to this transaction.

                                   
            Enquiries - London                  Enquiries - Santiago                                       
                                                                                                           
            Antofagasta PLC                     Antofagasta Minerals S.A.                                  
            Tel: [phone]               Alejandro Rivera                                           
            www.antofagasta.co.uk               Tel: [phone]                                        
                                                Email: [e-mail]                                
            Desmond O'Conor                                                                                
            Email: [e-mail]    Enquiries - Australia                                                   
       
            Bankside Consultants                N M Rothschild & Sons (Australia) Ltd (financial advisers) 
            Tel: [phone]               Tel: [phone]                                       
            Mob: [phone]               Marshall Baillieu                                          
                                                Chris Forman                                               
            Keith Irons                                                                                    
            Email: [e-mail]           Jackson Wells Morris (public relations advisers)           
                                                Tel: [phone]                                       
                                                Benjamin Haslem                                            
                                                Jakob Webster                                              
 

                      This information is provided by RNS
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