The NSW Resources Regulator has released a new safety animation recreating an underground mine fire at Perilya’s Southern Operations in Broken Hill, highlighting the chain of events that forced the evacuation of 46 workers.
The video reconstructs the January 12, 2025, incident, which occurred about 1000m below the surface during a remediation project to fill a void in the mine’s haulage shaft.
According to the regulator, the void was being filled with a two-part polyurethane (PUR) foam product commonly used in underground mining to stabilise ground conditions. Shortly after the foam was applied, heat generated during the chemical reaction is believed to have either self-combusted or ignited nearby flammable materials within the shaft.
Smoke and fumes quickly began to build underground, prompting an emergency evacuation call. Forty-six workers made their way to the surface, while five others remained temporarily in a fresh air base until mine rescue personnel confirmed it was safe to leave. No injuries were reported, although operations at the mine were halted for an extended period.
The regulator launched an investigation immediately after the event, later concluding the fire was caused by a combination of planning gaps, oversight challenges and shortcomings in risk management rather than a single failure.
Investigators found the remediation work had been planned without a physical inspection of the void due to known geotechnical risks. As a result, combustible materials such as timber supports and ventilation materials were not identified before the foam was pumped into the space.
Nearly two tonnes of PUR foam were injected into the void, filling about 80 per cent of the space. The product had not previously been used at the site and had not been confirmed as licensed for use in the New South Wales coal industry, contrary to what staff believed at the time.
The investigation also revealed that personnel were unaware of a 2021 safety bulletin warning that polyurethane foams should not be used to fill large voids due to their exothermic properties and flammability.
While some contractors raised concerns about heat and fume emissions on the night of the incident, the report noted hesitation in escalating the issue, contributing to delays in triggering a full evacuation.
Investigators also observed that none of the workers used their self-contained self-rescuer units despite the presence of smoke, highlighting opportunities to strengthen training and confidence in emergency equipment.
The regulator’s new animation outlines these findings and forms part of a broader effort to share lessons with the mining industry.
Five key recommendations have been issued to help prevent similar incidents. These include strengthening risk management processes for polymeric products, improving contractor management, tightening chemical management systems and reviewing emergency management plans.
The regulator has also called for a coordinated national review into how polymer-based products are used and regulated in mining, with the aim of developing clearer guidance and more consistent safety standards across Australia.
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