Rockwall collapses forces Koolan Island closure

IRON Ore exports from Koolan Island in Western Australia’s Buccaneer Archipelago are set to cease following a rockwall collapse at Mount Gibson Iron’s pit.

The “significant” rockfall occurred on the eastern footwall (island-side) of the Main Pit on the night of 16 October. MGI said no personnel were injured by the rockfall which had been monitored in advance with the site’s continuous radar coverage of pit walls.

“An exclusion zone was implemented in the Main Pit and all mining remains suspended. Following intensive assessment since the incident, including input from external geotechnical specialists, MGI has determined that remediating the rockfall-affected area and resuming mining is not viable given the safety risks of potential future instability and the time and investment required to mitigate such risks, especially in the context of the operation’s limited remaining mine life,” the company said.

Prior to the rockfall, production from Koolan Island was scheduled to conclude around September 2026. While the situation will be reviewed, MGI will make 250 employees redundant and end 200 contractor roles, keeping 75 on-site for the time being given the availability of ore stockpiles to meet near-term scheduled shipments as well as the potential for additional sales from lower grade stocks previously retained for blending purposes.

One affected contractor will be Svitzer, which has the tugs Woona and Hastings stationed at Koolan to handle MGI traffic. DCN has sought comment.

Additionally, MGI will accelerate progressive rehabilitation activities, which include removing the site’s infrastructure such as the airstrip, jetty, wharf, shiploader, accommodation village, access roads and site buildings.

According to the MGI website Koolan Island was acquired through the takeover of Aztec Resources Ltd in 2007, and the former BHP mine boasts Australia’s highest grade hematite ore reserves which average over 65% Fe.

MGI completed mine recommissioning and commenced shipments in April 2007. Mining was interrupted in late 2014 when the Main Pit flooded but continued in satellite pits until early 2016.  Production and sales of high-grade hematite recommenced in April 2019 following a two-year seawall reconstruction and mine refurbishment program. As of July 2024, Mount Gibson had exported in excess of 38Mt of ore from Koolan Island.