Purchase of Shares

Antofagasta PLC
27 February 2006


                                ANTOFAGASTA PLC

                 Antofagasta reaches 12.19% interest in Tethyan

London, 27 February 2006: Antofagasta PLC ('Antofagasta') is pleased to announce
that it has today filed a notice with the Australian Stock Exchange confirming
the on-market purchase of a further 4,300,000 shares at a price of A$1.20 per
share in Tethyan Copper Company Limited ('Tethyan') on Friday, 24 February
2006.  Antofagasta's on-market share purchases now total 16,142,910 Tethyan
shares, which represents an interest of 12.19% in Tethyan's issued share
capital.

On 14 February 2006, Antofagasta announced that it had reached agreement with
Tethyan on the terms for a recommended cash offer of A$1.20 per share for the
entire issued share capital of Tethyan.

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]

Desmond O'Conor                            Email: [e-mail]
Email: [e-mail]           Enquiries - Australia

Bankside Consultants                       N M Rothschild (Australia) Ltd
                                          (financial advisers)
Tel: [phone]   Tel: [phone]

Keith Irons                                Marshall Baillieu
Email: [e-mail]                  Chris Forman

                                           Jackson Wells Morris (public
                                           relations advisers)
                                           Tel: [phone]
                                           Benjamin Haslem
                                     

About Antofagasta PLC

Antofagasta PLC is a Chilean-based mining group listed on the London Stock
Exchange and is a constituent of the FTSE-100 index. Its principal mining assets 
include the Los Pelambres, El Tesoro and Michilla mines and the Esperanza copper project. In
addition to copper mining, Antofagasta's interests include rail and road
transport operations and water distribution.

About Tethyan Copper Company Limited

Tethyan is a company listed on the Australian Stock Exchange. Its principal
assets are a 75% interest in the exploration licence encompassing the highly
prospective Chagai Hills region of North West Pakistan known as Reko Diq, which
includes the Tanjeel Mineral Resource and the Western Porphyries, and a 100%
interest in certain other licences in the region. This mining district hosts
significant copper-gold porphyry deposits as part of an extended copper-gold
belt. Tethyan has reported total indicated and inferred mineral resource
estimates at these properties of 2.4 billion tonnes with a copper grade of 0.51%
and a gold grade of 0.27 grams per tonne. The resource estimates include
probable reserves at the Tanjeel Mineral Resource of 128.8 million tonnes with a
copper grade of 0.7%. Reserve and resource estimates have been reported by
Tethyan to JORC standards. Tethyan had gross assets of A$28.8 million as at 30
June 2005 and reported a net loss of A$1.7 million for the year ended 30 June
2005.





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