Recently, a haul truck operator at an underground metalliferous mine in Victoria was hauling material along a drive when flames were seen coming from the truck’s engine bay area.
The truck’s aqueous film forming foam (AFFF) fire suppression system was ineffective in extinguishing the fire and a portable fire extinguisher was then used to staunch the flames.
WorkSafe Victoria investigated the incident and found the fire happened because a high-speed drive shaft bearing next to the articulation joint overheated.
It was discovered the general-purpose grease recommended by the supplier was not suitable for high-speed bearings, and the AFFF system did not provide coverage of the bearing.
“There is a risk of fire if high-speed bearings on mobile mining plant fail,” WorkSafe Victoria said.
“Failed bearings can cause friction. This friction can cause heat that ignites lubricating greases and oils.”
According to WorkSafe Victoria, ways to control risks associated with high-speed bearing failure on mobile equipment include:
- Check bearings for signs of wear or failure during mobile plant maintenance inspections
- Use lubrication greases on high-speed bearings that meet manufacturer specifications
- Develop preventative maintenance programs for mobile plant that:
- include appropriate change-out frequencies for high-speed bearings – these should be developed in consultation with the manufacturer
- consider site conditions
- Include relevant items from manufacturer safety or service bulletins in the site’s preventative maintenance program
In 2022, there were five fires involving the high-speed drive shaft bearings on underground loaders in Queensland metalliferous mines. These occurred across different mines, with some mines having multiple fires.
Although no one was injured in the incidents, the fires had the potential to cause significant adverse effect to the safety or health of workers.
One of the fires was unable to be extinguished, causing a mine evacuation and shutdown for several days and total loss of the machine.
“Employers must eliminate any risks to health and safety at work,” WorkSafe Victoria said.
“If employers cannot eliminate the risks, they must reduce them so far as is reasonably practicable.”
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