On September 18 2017, police confirmed the fire was caused by a malfunctioning transformer exploding.

“The fire was fuelled by oil and contained within the transformer causing extensive heat and black smoke to be emitted in the area,” a police spokesperson said.

A Glencore spokesperson confirmed that an independent expert from the Department of Natural Resources and Mines had investigated the cause of the malfunction, but declined to share their findings.

The explosion happened at 2.30pm at the Pendine Street Substation in Mount Isa, which is predominantly used to power mining operations above ground. 

Queensland Emergency Services responded to the incident and there were no injuries reported. The fire caused a partial power outage to the mine’s surface operations.

Police say the fire at Mount Isa Mines switch yard on Monday is not suspicious, and was caused by a malfunctioning transformer exploding, creating large flames and thick plumes of black smoke.

“The fire was fuelled by oil and contained within the transformer causing extensive heat and black smoke to be emitted in the area,” a Mount Isa Police spokesperson said.

The resulting fire caused significant damage to the power station, rendering the site inoperable.

All emergency services were on site, including two fire engines and police, who established cordons on Railway Avenue to redirect traffic.

Firefighters used continual cooling and a foam suppressant, with the fire eventually being extinguished at 8pm on Monday, September 18.

Queensland Fire and Rescue Service were on site monitoring the toxicity and oxygen levels within the vicinity, with no readings of concern being identified.

Mount Isa Police District acting Inspector Brad Inskip said police were working with the Department of Natural Resources and Mines (DNRM) to investigate the cause of the fire. 

An electrical inspector from DNRM was on site assessing the cause of the incident, which is not being treated as suspicious.

“There’s basically no indication at this stage of suspicious activity. We just need to investigate so that’s the case,” acting Inspector Brad Inskip said. 

He said the fire was not at risk of being exposed to any nearby fuels or toxins from the mine or acid plant. 

“It was pretty much contained to that one specific site and it was isolated very quickly,” acting Inspector Inskip said. 

“There was a delay in firies being able to access the scene. It took a while to shut power to the area for firies to enter,” he said.

On Tuesday morning Mount Isa Mines released a statement saying their underground operations were back up and running.

“As always, the safety and health of our employees is our highest priority.”