A fire occurred in the engine bay of a drill rig used for development and production at an underground metalliferous mine. The drill rig was tramming to the surface workshop. As the drill rig reached the surface, an employee noticed flames in its engine bay and notified the operator. The unit was parked and the aqueous film forming foam fire suppression system was activated to suppress the flames.
Upon investigation, no signs of mechanical or structural failure were detected that may have provided potential fuel sources.
Further analysis discovered remnant paint can pieces and paint within the engine bay. This revealed that radiant engine heat had caused a paint can to burst, which provided an ignition source for the vaporised paint.
Figure 1: The drill rig after the fire incident
Figure 2: Base of remnant paint can
Unsecured combustible objects or debris on mobile plant can create risks to the health and safety of employees and independent contractors by introducing fuel sources into potential ignitions zones, for example hot surfaces on engines and exhaust systems.
Recommended ways to control risks
To reduce the risk of mobile plant fire, mine operators must:
- ensure that when combustible items are carried on mobile plant that they are secured and not located within potential ignition zones
- review the adequacy of storage compartments and, if necessary, revise the need for transporting objects/items on mobile plant
- perform a risk assessment to identify all potential hazards and assess the adequacy of all considered control measures, including what objects or items can be transported on mobile plant and how such items will be secured
- ensure pre-task inspections target combustible items located within potential ignition zones
- ensure employees are provided with information, training and instruction about how to transport combustible materials in a mine
Mine operators should consult with employees and include a broad range of expertise and personnel when developing risk assessment teams to ensure all aspects of risk are considered.
Under the Occupational Health and Safety Act 2004, employers must, so far as is reasonably practicable, provide and maintain a working environment that is safe and without risks to the health of employees and independent contractors. This means employers must eliminate so far as is reasonably practicable the risk associated with operating plant in the workplace. Where the risk cannot be eliminated, it must be reduced so far as is reasonably practicable.
Under the Occupational Health and Safety Regulations 2017 (OHS Regulations), mine operators must:
- identify all mining hazards at their mine and assess associated risks, so far as is reasonably practicable
- implement risk controls that eliminate or reduce risks, so far as is reasonably practicable
- establish and implement a safety management system for the mine, which provides a comprehensive and integrated management system for all identified risks