A mine worker who was in an elevated workbox suffered a fractured lower leg and back injuries after the workbox detached and fell two metres from a loader.
In the circumstances leading up to the incident, two engineering maintenance workers were tasked with installing a cable at the roof level using a loader and workbox in an underground metalliferous mine.
The machine they were using was a wheel loader that had been converted to an integrated tool carrier, but the workbox attachment assembly was not fully compatible with the attachment assembly on the loader.
When the locking pins were disengaged, the attachment was able to swing, disengaging from the attachment hook.
The hydraulic isolation valve was not engaged to stop the locking pin (that was holding the workbox) from disengaging during operation.
The loader operator selected the workbox locking pin release switch, and the locking pin disengaged causing the workbox to detach from the loader and fall to the ground.
The NSW Resources Regulator attended onsite and conducted an assessment of the mine’s investigation into the incident.
In a subsequent safety alert, the regulator said mine operators should review their safety management systems, particularly focusing on ensuring that:
Workbox attachment systems are fit-for- purpose with machine attachment systems
Change management arrangements for the modification and maintenance of workbox attachment systems are to be assessed in consultation with relevant equipment manufacturers or engineering specialists
For any modified plant, mines should conduct thorough assessments to ensure compatibility with existing site equipment and attachments
Operational switches in mobile equipment are of an appropriate type, positioned and labelled appropriately to prevent inadvertent operation and consider additional barriers or protection of the locking pin release switch
Information, instruction and training is provided to, and implemented by workers for the safe use of workboxes.