Australian miner Mount Gibson will end operations at its high-grade Koolan Island iron ore mine offshore Western Australia (WA) state, following a rockfall on 16 October.
Part of the pit wall collapsed eight days ago with no injuries to staff but the company found that resuming mining was not viable following an assessment, Mount Gibson said on 24 October.
Operations will not restart, ending mining ahead of the project's planned closure in around October 2026.
Processing will continue using available stockpiles for near-term scheduled shipments, Mount Gibson said, with potential for sales from lower grade stock, which it had been using for blending.
The firm sold 550,000 wet metric tonnes (wmt) at an average grade of 64.3pc Fe in July-September and has now cancelled its sales guidance for the year to 30 June 2026 of 3-3.2mn wmt.
Mount Gibson had identified remaining ore reserves of 4.1mn t at Koolan Island and sold 2.61mn wmt in 2024-25, down from 4.1mn wmt a year earlier.
It had expected shipments to increase in the final nine months of its 2025-26 fiscal year after bulk waste stripping activity occurred in July-September.
Mount Gibson purchased the Koolan Island mine in the Buccaneer Archipelago off WA's northern Kimberley region coast in 2007. Formerly operated by Australian miner BHP, the project contains Australia's highest grade hematite reserves averaging over 65pc Fe and has produced more than 40mn t of ore.
The Argus 65pc Fe iron ore index was up by 40¢/dry metric tonne (dmt) to $119.74/dmt on 23 October while the Argus 62pc Fe iron ore index rose by 15¢/dmt to $105.05/dmt.

