Copper futures surged over 4% to $4.77 per pound, the highest in two months, after Freeport-McMoRan declared force majeure on supplies from its Grasberg mine in Indonesia, the world's second-largest copper source.
The move follows a severe accident on September 8, which killed two workers and left five missing amid a mud flow of roughly 800,000 metric tons.
Freeport cut its quarterly copper and gold sales guidance by 4% and 6%, respectively.
The disruption highlights the copper market's sensitivity to supply shocks, compounded by Hudbay Minerals halting operations at its Peruvian Constancia mine due to protests.
Grasberg alone accounts for 3.2% of global mined copper, nearly 30% of Freeport's copper output, and 70% of its gold production, showing the scale of the impact.
Prolonged disruptions could further boost prices and strain the smelting industry.
