Sandfire Resources Ltd has been fined $551,250 and ordered to pay $4,670 in costs after a rock fall pinned a worker to an elevated basket he was working in at the company's DeGrussa underground mine.
As the principal employer, Sandfire Resources pleaded guilty in the Perth Magistrates Court on 15 November 2023 to failing to take appropriate measures to ensure workers at the mine were not exposed to hazards.
In May 2020, an underground explosives operator was working from an elevated basket attached to a mobile charging unit when the ground above him collapsed. The rock fall pushed the basket to the ground, trapping the worker inside and making it difficult for him to breath.
Co-workers thought the explosives operator had been killed as they could not hear him respond to their calls. The men worked for nearly 20 minutes to free him. During the rescue, the workers were unsure of the integrity of the ground above them and feared they might be killed by a further rock fall.
The trapped explosives operator was eventually freed having suffered scratches, lacerations and broken ribs.
WorkSafe Chief Inspector of Mines Christina Folley said underground mines require detailed analysis of rock structures and planning to ensure persons working underground are safe.
"The worker involved in this rock fall is extremely lucky to be alive, and the situation may have been even worse had more ground fallen during his rescue," Ms Folley said.
"Underground workers had raised concerns about the integrity of the ground with Sandfire Resources in the days prior to the rock fall.
"While the company implemented remedial measures, they were inadequate as their actions were based on inaccurate information and did not take into account significant geological features in the area.
"Operators must apply sound geotechnical engineering practice to determine the ground conditions, the ground support and reinforcement requirements, as well as the size, shape and orientation of all the openings that can be safely excavated.
"Most importantly, the mine's Ground Control Management Plan must be up-to-date and accurate."
Sandfire Resources' DeGrussa copper mine is located around 900 kilometres north east of Perth within the Shire of Meekatharra.
The company completed underground mining operations at the site in October 2022 and ceased processing operations in May 2023.
The mine consisted of nearly 40km of lateral development, allowing the company to extract ore from multiple faces on multiple levels.
The site used a stope mining model that required the setting of explosives to breakdown rock formations for removal to the surface.
