1st Quarter Production Report

Antofagasta PLC 30 April 2002 30 April 2002 Antofagasta plc Quarterly Production Report - Q1 2002 Highlights • Group copper production of 108,900 tonnes in Q1 compared with 121,600 tonnes in Q4 2001 due to lower ore grades at Los Pelambres as expected • Group cash costs of 39.2 cents per pound in Q1 compared with 37.9 cents in Q4 2001 • Ore processing level at Los Pelambres up 8% to 113,600 tonnes per day • Michilla's cash costs below 60 cents per pound in Q1 Q1 Q2 Q3 Q4 Acc Acc Full Year Group Total 2002 2002 2002 2002 2002 2001 2001 Total copper production 108.9 108.9 92.0 445.0 ('000 tonnes) Weighted average 39.2 39.2 43.2 38.8 Cash costs (cents per pound) Los Pelambres The ore processing level at Los Pelambres increased 8% from 105,200 tonnes per day (tpd) in Q4 2001 to 113,600 tpd in Q1 this year. This higher processing level is expected to be maintained this year. Although throughput increased, copper production in Q1 fell 13.6% to 77,154 tonnes compared to 89,422 in Q4 mainly due to lower ore grades as expected under the mine plan for 2002. Cash costs at 35.9 cents per pound were marginally higher compared to Q4 and as previously stated are expected to increase in the following months due to the lower ore grades. Molybdenum concentrates are an important by-product for Los Pelambres and will be included in future Quarterly Production Reports. Molybdenum produced in Q1 was 2,400 tonnes compared to 2,100 tonnes in Q4. Total production in 2002 will be comparable to 2001. El Tesoro El Tesoro produced 19,340 tonnes in Q1 compared to 19,257 tonnes in Q4 2001. Cash costs were 39.6 cents per pound, within the expected costs levels for 2002. Michilla Q1 production was 12,456 tonnes compared to 12,895 tonnes in Q4 2001. Production of cathodes was affected while the enlarged crushing line was installed, and the additional crusher will boost annual production to 52,000 tonnes in 2002. Recoveries have risen consistently during the last four years due to optimisation of the processes and reached 77.4% during Q1. During the first months of 2002, the Cuprochlor process, which has been developed and patented by Michilla, has resulted in higher recoveries of sulphide ores. Approximately 12% of Michilla's ore is now being treated using this process with recoveries obtained of over 80%. Cash costs in Q1 were 59.0 cents per pound as a result of the cost reduction programme implemented in Q4 last year. Rail and Road Transport Rail tonnages were slightly lower at 1.04 million tons compared to 1.05 million tons in Q4 2001 caused by lower movements on the Andino Railway compensated by higher tonnages on the FCAB's operations within Chile. Q1 Q2 Q3 Q4 Acc Acc Full Year Los Pelambres 2002 2002 2002 2002 2002 2001 2001 Daily average ore treated 113.6 113.6 98.5 104.7 ('000 tonnes) Average ore grade 0.89 0.89 1.04 1.05 (%) Average recovery 91.2 91.2 91.6 92.4 (%) Concentrate produced 189.7 189.7 194.6 856.9 ('000 tonnes) Average concentrate grade 42.1 42.1 42.8 43.6 (%) Fine copper in concentrate 79.8 79.8 83.2 373.8 ('000 tonnes) Payable copper in concentrate 77.2 77.2 80.5 361.5 ('000 tonnes) Payable molybdenum in 2.4 2.4 1.2 6.9 concentrate ('000 tonnes) Cash costs 35.9 35.9 39.2 35.3 (cents per pound) Q1 Q2 Q3 Q4 Acc Acc Full Year El Tesoro 2002 2002 2002 2002 2002 2001 2001 Daily average ore treated 20.6 20.6 - 17.7 ('000 tonnes) Average ore grade 1.34 1.34 - 1.44 (%) Average recovery 76.5 76.5 - 76.1 (%) Copper cathodes 19.3 19.3 - 34.0 ('000 tonnes) Cash costs 39.6 39.6 - 39.6 (cents per pound) Q1 Q2 Q3 Q4 Acc Acc Full Year Michilla 2002 2002 2002 2002 2002 2001 2001 Daily average ore treated 11.8 11.8 11.6 12.2 ('000 tonnes) Average ore grade 1.48 1.48 1.53 1.49 (%) Average recovery 77.4 77.4 72.4 74.8 (%) Copper cathodes 12.5 12.5 11.5 49.6 ('000 tonnes) Cash costs 59.0 59.0 71.6 64.5 (cents per pound) Q1 Q2 Q3 Q4 Acc Acc Full Year Transport 2002 2002 2002 2002 2002 2001 2001 Rail tonnage transported 1,037 1,037 905 3,899 ('000 tons) For further enquiries: Philip Adeane, Antofagasta plc (44) 20 7382 7862 nwakefield@antofagasta.co.uk Hussein Barma, Antofagasta plc (44) 20 7382 7862 hbarma@antofagasta.co.uk Alejandro Rivera, Antofagasta Minerals (56-2) 377 5145 arivera@aminerals.cl Keith Irons, Bankside Consultants (44) 20 7444 4155 keith@bankside.com This information is provided by RNS The company news service from the London Stock Exchange

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