While ICN has received separate confirmation that the incident took place at Oaky North, the Queensland government alert said the “substantial fire” occurred near the breaker shaft and machine system hydraulics on a feeder breaker at an underground coal mine.

“The site investigation has so far determined the fire on the feeder breaker started close to where a rotating shaft had rubbed through a cable containing an intrinsically safe electrical circuit,” the alert commented.

“It appears a guard protecting the rotating shaft was missing and the cable was not secured properly allowing them to make contact.

“Investigations are continuing to look into the possibility the damaged electrical circuit generated enough heat to initiate a fire in a build-up of grease, oil, coal and possibly other combustible material.”

The following key findings were made, with some them indicating that inspection failures occurred.

• A guard was not replaced after it was removed for maintenance work
• Grease, oil and coal build up in the area of the fire was not identified or managed
• Inspections had not identified the mechanical damage to the electrical cabling
• Subsequent tests and checks of the intrinsically safe electrical circuits and equipment identified no certification or compliance issues
• Further testing is to be carried out to identify causal factors for heat generation from intrinsically safe electrical circuits

Queensland’s Department of Natural Resources and Mines has separately provided more detail than the alert on the firefighting effort.

“The fire was observed at approximately 1.45 and was successfully extinguished by 2.10 am,” A DNRM spokesman told ICN.

“Two personnel initially used handheld 9kg fire extinguishers to address the fire then a third person used a water hose to assist.”

ICN also understands that the flames were observed to have reached up to 1.3m to the rib and 1.5m to the roof.

Other observations so far included that the heat seemed most intense around the electrical solenoid block.

While the cause is still unknown there are some views that an intrinsically safe wire, that was also covered in grease, was broken prior to the ignition.

The feeder breaker was also considered to be unused for more than two hours before the incident occurred.

Safety reporting

While feeder breakers are typically located in intake areas, effectively ruling out spontaneous combustion fears, and it is hard to know the circumstances faced in the firefighting effort, the 25 minute duration of the fire underground is a rare event in itself for Queensland’s UG coal scene.

“This like any underground coal mine fire is serious as it has the potential to effect multiple mine workers and depending on its location could have far worse results if not found or controlled,” CFMEU mining and energy division Queensland district president Stephen Smyth told ICN.

While the complexity of the incident, with the cause still unknown, created reporting challenges Smyth was not satisfied with the delay to communicate findings to the wider industry.

“This demonstrates that there are failures within the system if a HPI like this takes nearly 12 months to action,” Smyth said.

Recommendations

While all contributing factors to the incident are not yet established, the government alert made the following recommendations for mines to ensure:

• All guards are correctly installed
• Electrical circuits, including intrinsically safe circuits and associated cables, are adequately protected and secured to prevent damage
• Maintenance strategies include regular checking of electrical cabling, including intrinsically safe electrical circuit external cabling
• Housekeeping practices prevent the build-up of contamination such as oils, grease, coal or other flammable materials in the vicinity of electrical equipment and cabling.

ICN has sought comment from Glencore.