Mount Gibson Iron to cut 450 jobs amid mine closure 

Mount Gibson Iron (ASX: MGX) will close its Koolan Island mine operations following a significant rockfall. 

Production from Koolan Island was previously planned to conclude around September 2026. 

Remediating the affected area and resuming mining is not viable given the safety risks and potential future instability, according to Mount Gibson Iron. 

Mount Gibson Iron will retain about 75 site personnel for continued processing and rehabilitation activities. The company expects about 250 redundancies and the loss of 200 contractor roles. 

Mount Gibson chief executive Peter Kerr comments on the closure.  

“It is extremely disappointing for the company and its people that we must prematurely ramp down operations at Koolan Island. However, the physical safety of our personnel is our prime consideration,” he said. 

“We will now be working closely with our site team, the Dambimangari Traditional Owners and other relevant stakeholders to responsibly manage the transition and preserve a strong legacy in the region.” 

Net costs associated with this transition are estimated at about $30-40m, including progressive rehabilitation work. 

Mount Gibson iron says the rockfall incident does not impact its previously announced acquisition of a 50% interest in the Central Tanami gold project, which is scheduled for completion on or before March 31, 2026.