Workers at an underground coal mine in New South Wales are safe after a fire broke out, narrowly avoiding an explosion.
The incident occurred when the operator of a load haul dump truck was shunting to allow other vehicles to pass.
The operator raised the quick detach system (QDS) kibble to clear the other equipment in the cut-through he was shunting in, cutting through a high roof.
Once the other vehicles were cleared, the operator drove out of the cut-through and turned outbye on the travel road, but did not lower the QDS kibble.
The inbye edge of the kibble hit several items hanging from the roof of the travel road, including several roof bolts and two 6.6 kilovolt (kV) cables, one 1kV cable.
One of the 6.6kV cables experienced a phase-phase fault, causing the protection to trip on short circuit.
“The mine has determined that the fault protections settings for the 6.6kV cable were incorrect and were lowered to more than half the original setting,” the NSW Resources Regulator said.
“On inspection of the cable, it was suspected that the heat generated from the arc fault ignited its internal tar or insulation.
“The flame was described as being like a ‘candle’.”
The fire was quickly extinguished, and thankfully there was no build-up of material on the cable that could have led to an explosion.
The Regulator urged operators to ensure a robust electrical fault protection study has been completed by a competent electrical engineer.
“Systems must be in place to ensure that the protection study is implemented and maintained,” the Regulator said.
“Mine workers must ensure that loaded vehicles are always driven with the load as close to the ground as reasonably practicable.
“Workers must also remain situationally aware to ensure hazards are identified and controlled.”
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