A significant blow to the Western Australian mining industry has emerged with Mount Gibson Iron announcing the immediate closure of its Koolan Island mine in the Kimberley region following a “significant” rockfall that rendered the site unsafe. The Australian Securities Exchange (ASX) announcement confirmed around 450 redundancies, marking one of the largest job losses in the remote mining sector for years.
What Happened
Late last week, a large-scale rockfall occurred at the eastern footwall of the main pit at Koolan Island, located in the Buccaneer Archipelago off WA’s north-west coast. After an intensive assessment, the company concluded that remediating the affected area and safely resuming mining operations was not viable.
Operations were previously scheduled to wind down in September 2026, but the unforeseen geological event has accelerated the closure timetable. Of the workforce, about 250 staff and 200 contractors will be made redundant, while approximately 75 employees will remain onsite to manage processing of remaining ore and undertake rehabilitation works.
Safety and Stakeholder Concerns
Mount Gibson’s CEO, Peter Kerr, stated that the decision was taken with “safety as the company’s highest priority.” He emphasised the company’s commitment to working with the Dambimangari Traditional Owners and other stakeholders on a responsible transition.
The site has a complex history. Koolan Island is among Australia’s oldest iron-ore operations, originally operated by BHP before Mount Gibson recommissioned it in 2007. Past challenges included a major seawall collapse in 2014, which flooded the pit and led to a suspension of operations until 2019.
Economic and Regional Impact
The closure has far-reaching implications:
- Jobs and Local Economy: The loss of 450 roles is a heavy hit to the Kimberley workforce and the logistics and services sectors that supported the mining operation.
- Project Pipeline Disruption: The sudden wind-down may impact contractors and supply-chain businesses that counted on continuity of operations into 2026.
- Investor Sentiment: Mount Gibson confirmed the closure will not affect its acquisition of a 50 % interest in the Central Tanami Gold Project, but market confidence could be shaken by the abrupt termination of mining operations.
- Rehabilitation Costs and Legacy: With mining ceasing ahead of schedule, the task of rehabilitation and environmental management becomes more urgent and potentially costlier.
What Happens Next
- The 75 remaining employees will focus on ore processing and accelerate rehabilitation at the site, working alongside stakeholders and Traditional Owners.
- The company must now manage the mine closure process, including environmental safeguards, infrastructure decommissioning, and workforce support.
- Further announcements are expected regarding the fate of mining equipment, infrastructure assets and potential reuse or winding down of site facilities.
- Government agencies and industry observers will likely examine how remote-site mines handle risk management of underground and open-pit hazards, potentially influencing regulation.
Why It Matters to Australia
This case illustrates several broader themes crucial to the Australian mining sector:
- Risk Management in Remote Mines: The event underscores how geological hazards can rapidly shift project viability—even for established operations.
- Transition Planning: While mines often have scheduled wind-down phases, unscheduled closures heighten the need for companies to plan for workforce, social and environmental transition.
- Regional Economic Vulnerability: Remote mining towns and island operations are particularly exposed when large employers exit or cease operations prematurely.
- Investor and Community Confidence: Market and stakeholder trust can erode when mines wind up early, emphasising the importance of transparency and proactive contingency management.
Final Takeaway
The closure of Koolan Island’s mine by Mount Gibson marks a significant shift for the region and the company. What began as a major rockfall event has cascade effects: job losses, community impacts, project disruption and heightened industry scrutiny. For the mining sector and regional Australia alike, this episode underscores that safety, geology and transition plans are just as critical as ore grades and export markets.
