The NSW Resources Regulator recently issued a safety alert for the mining industry following a fire which occurred on an agitator truck in an underground metals mine in Cobar on 13 April 2019.
The fire spread quickly with non-metallic engine covers and guards adding to the fuel load and the intensity of the fire. 19 workers underground at the time had to retreat to refuge chambers while the fire was brought under control.
The alert found that the truck’s fuel tank was punctured, allowing diesel fuel to escape. The truck was being driven down the decline.
At a local up-grade, the operator noticed additional drag on the engine and towards the top of the local climb the operator discovered a fire. The operator managed to escape from the truck without injury.
A number of issues have emerged from the event that concern the NSW Resources Regulator, according to the alert:
The fire suppression system nozzles were only targeting hot surface ignition in the engine bay.
The truck contained substantial non-metallic fuel loads adjacent to the engine bay, in sound suppression materials, and in the operator cabin, and the suppression system was not capable of extinguishing the fire.
Non-metallic, non-fire resistant materials were used for covers, guards, and components.
Several components exploded as the fire took hold. Workers reported to have heard three explosions, which may relate to the three hydraulic accumulators on the truck.
Toxic products of combustion were distributed throughout the mine by the ventilation system.
The hand-held extinguishers mounted on the machine were not readily accessible to the operator from the cabin or as they dismounted the vehicle
Wheel chocks for the machine were not readily accessible to the operator after it caught.
Services installed in the decline were damaged by the fire. It is believed that a melted water line doused the fire.
“Vehicles used in underground mines must be rigorously assessed with regard to the risk of fire,” the alert said.
“A recent assessment program focusing on the contribution of maintenance practices to plant fires in open cut mines identified significant deficiencies with regard to fire risk assessments.
“Designers should minimise the use of non-metallic materials that burn and produce toxic emissions.
“Trucks that are not specifically designed for underground conditions may require further scrutiny to assess the content of non-metallic materials.”