Falls in shares of London's mining heavyweights weighed on the FTSE 100 on Tuesday morning, as copper and iron ore prices fell.
Anglo American PLC (LSE:AAL) shares fell 3.4% and Antofagasta PLC (LSE:ANTO) dropped 3.1%, two of the more copper-focused miners, while Glencore PLC (LSE:GLEN) declined 2.4% and Rio Tinto Ltd (LSE:RIO, ASX:RIO, OTC:RTNTF) decreased 1.9%.
Precious metals miners Fresnillo and Endeavour Mining were down 1.5% and 1.05% as gold and silver prices dropped too.
Copper led the sell-off of base metals, falling 2% this morning on the London Metal Exchange to $10,622 a tonne, down nearly $600 from recent record highs.
This is due to what mining analyst John Meyer at SP Angel said reflected a China capacity cut and supply boost from Chile's national mining company Codelco.
"The move follows a wider sell-off in base metals, with aluminium and tin also sliding," he said, after the metals spectrum enjoyed a strong rally through the third quarter on the back of a weaker dollar, increased Federal Reserve rate cut expectations and steady China demand.
"However, calls for capacity cuts from China’s major non-ferrous metals body has raised concerns."
China copper refining capacity rose 12% year-on-year in the first nine months of 2025, whilst utilisation sits at circa 85%, he said.
Glencore PLC (LSE:GLEN) stated yesterday it would close the Horne smelter in Canada amid uncompetitive cost dynamics.
Chile's Codelco eased concerns over supply with a promising update from El Teniente, where Meyer said grinding operations and smelting are returning to normal, with Codelco expecting 2025 production to be higher than 2024, despite the disruption.
"However, we expect the impact of lower production from Grasberg, El Teniente, Kamoa Kakula and QB2 to all feed into tight markets going forward, should demand remain healthy."