Antofagasta Cuts Copper Target as FTSE 100 Mining Stocks Fall

Shares in Antofagasta plummeted Thursday morning, making the Chilean mining group the worst performer on London's FTSE 100 index. The stock tumbled 4.9% after the company downgraded its long-term copper output forecasts following adverse weather conditions in South America.

The London-listed miner reduced its projected copper production for 2026 to a range between 625,000 and 655,000 metric tons, down from its earlier target of 650,000 to 700,000 tons. The adjustment stems from an operational halt at its Los Pelambres mine during July, caused by extreme torrential rainfall in Chile.

The severe weather prompted Chilean authorities to declare a state of catastrophe across the Coquimbo Region. While essential machinery and heavy infrastructure at Los Pelambres escaped major structural damage, Antofagasta confirmed that water management installations and pipeline platforms require extensive repairs before full capacity can be restored.

The sharp decline in Antofagasta's share price dragged down the broader UK mining index, rendering the FTSE 100 an underperformer relative to competing European equity benchmarks. The market reaction overshadowed broader economic data showing the British economy expanded by 0.4% in the second quarter, aided by June growth linked to warm weather and major sporting events.