WA miner fined $35k for sinkhole incident

West Perth-based mining company Minjar Gold has been fined $35,000 after a blast truck and integrated tool carrier fell into a 13-metre sinkhole in 2018.

Minjar Gold, a subsidiary of Shanghai Stock Exchange-listed Shandong Tyan Home, appeared in the Perth Magistrates Court on March 29 after pleading guilty to failing to provide and maintain a safe work environment.

According to WorkSafe WA, the 13-metre sink hole was formed after the ground subsided in the floor of an open-cut gold pit at the Golden Grove mine south-east of Yalgoo. 

The incident did not cause any injuries, but four employees from the blast crew had been working close to the bomb truck minutes earlier.

Several charged blast holes were also engulfed by the sinkhole collapse.

“Investigations found the mining operators had not treated backfilled underground workings as a void, allowing work to be carried out above an area of unknown stability,” according to Work Safe.

Minjar Gold has also been ordered to pay $10,000 in costs, as well as the $35,000 fine.

Acting WorkSafe chief inspector mines Christina Folley said Minjar Gold should not have allowed workers and plant to operate in the pit.

“The workers in the area shortly before the incident were lucky to escape and this incident could have resulted in serious injury or loss of life,” he said.

“While the company had identified the stope void as a risk, it did not implement the recommended controls.

“Minjar Gold should have properly applied a voids procedure or other control such as confirmation of backfill competency, probe drilling or a geotechnical review.”

Minjar Gold had an agreement with Golden Grove Operations to mine and process gold oxide ore at the same operation near Yalgoo.

Golden Grove Operations was fined $35,000 in June 2022 for its role in the same sinkhole incident. 

Ms Folley said geotechnical hazards were well recognised in the mining industry and that mine operators must monitor and record any change in underground conditions below open-cut workings.

“Voids pose a significant workplace risk, so mine operators must ensure underground workings close to active work areas are marked on all plans,” she said.

“Minjar Gold should have developed safe working practices that did not presume any stope was tight filled.”