A fourth year electrical apprentice at an open cut coal mine in New South Wales has been sprayed with nitrogen and hydraulic oil during maintenance activities, prompting warnings from the state’s safety watchdog.
The apprentice was fault finding on an electrical pressure sensor on the right-hand front strut of a CAT 775G service truck when the incident occurred.
After finding no fault on the electrical pressure sensor, a supervisor overseeing the works directed him to test the strut’s internal pressure at the charge valve.
Rather than attaching the original equipment manufacturer (OEM)-recommended pressure-measuring assembly, the apprentice unscrewed the charge valve, resulting in the forcible ejection of the valve and the contents of the strut, including nitrogen and hydraulic oil, which sprayed the apprentice from the valve port.
Under the weight of the truck, the strut retracted allowing the truck to fall about 200mm and pushing the apprentice from the step ladder from which he was working.
The NSW Resources Regulator investigated and delivered a key warning to industry, emphasising that supervisors have a duty to ensure that workers under their care are not exposed to dangerous situations.
“Supervisors should be trained to recognise the potential hazards associated with all energy sources and should assess the risks involved when working with pressurised systems and have appropriate controls in place to manage the risk,” the Regulator said.
“Mine operators should have documented safe systems of work for the maintenance or repair of wheel strut charge valves with the documentation being readily available to those undertaking such tasks.
“OEM recommendations must be considered when developing procedures for tasks.”
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