$540K fine for underground mining contractor after fatal rock fall

A mining contractor has been fined $540,000 — and ordered to pay $8414 in costs — after a rock fall in a ventilation shaft of an underground gold mine that killed a driller and injured a probationary offsider.

The incident

The incident occurred at the Hamlet Underground Gold Mine near Kambalda in October 2022. A driller and probationary offsider employed by RUC Mining Contractors Pty Ltd were engaged in disassembling a reamer. They did this by unbolting and removing wings attached to the reamer’s centre box at the base of a ventilation shaft, which had been drilled using an underground mining technique known as raise boring; reamers must be disassembled and removed from the holes they create.

The disassembly method employed by RUC Mining Contractors at the time of the fatal incident involved pulling the reamer’s head to the side of the raise, rotating the reamer’s head to position its worked-on parts beneath supported ground and behind protective curtains. RUC Mining Contractors staff were experiencing difficulties hanging the curtains — made from rubber conveyor belt material — and draping them over the reamer’s head because the reamer was not centred in the hole.

An RUC Mining Contractors employee booked a jumbo operator to install a torque plate on the ventilation shaft’s right-hand wall to enable the centring of the reamer in the hole, but disassembly work continued in the meantime. The RUC Mining Contractors area manager visited the mine during that period and observed that the protective curtains were not properly installed. The area manager also instructed the driller to climb off the reamer — as the driller was working too close to the curtains directly beneath the hole and, consequently, beneath unsupported ground.

About an hour after the RUC Mining Contractors area manager left the ventilation shaft, the fatal incident occurred. The driller was standing on top of the reamer’s head, undoing bolts on its top and the probationary offsider was standing on the ground close to the reamer’s edge — feeding the driller the air hose for the rattle gun they were using. The driller was standing under unsupported ground.

The driller died instantly when a rock fall happened, striking the driller and causing the probationary offsider to fall to the ground. The probationary offsider suffered minor physical injuries and a psychological injury.

Fine and regulator comment

In the Kalgoorlie Magistrates Court, RUC Mining Contractors Pty Ltd pleaded guilty to two counts of the same offence — exposing a worker to a risk of death, injury or harm to health, contrary to sections 19(1) and 32(1) of the Work Health and Safety Act 2020. This offence does not indicate that the breach caused the fatal incident. However, it highlights a failure in relation to risk management.

A single fine of $540,000 was imposed on RUC Mining Contractors by Magistrate William Yoo for the two counts; RUC Mining Contractors had been engaged by Gold Fields Australia Pty Ltd to conduct raise bore-drilling work at the Hamlet Underground Gold Mine — part of its St Ives Gold Mine.

“This tragic incident is a reminder that raise-boring activities can involve serious hazards, not only from rock falls but also from equipment failure, ground failure and the inrush of mud, drill cuttings, water or gas,” WorkSafe WA Commissioner Sally North said.

“I encourage all mining operators and contractors involved in raise-boring activities to ensure a safe system of work is in place to ensure risks have been eliminated or minimised, and that workers are consulted on the procedures, equipment and training.”

Guidance on reducing risks in raise-boring activities is available here, on WorkSafe WA’s website.

Image credit: iStock.com/Natalya Bosyak. Stock image used is for illustrative purposes only.