Fortescue Metals Group is under fire over the deaths of two contractors and a string of safety breaches as investigators place the company’s operations under the microscope.
The world's fourth biggest iron ore miner has expanded rapidly on the back of strong Chinese steel demand, using a host of contracting companies to build and operate its iron ore operations in the Pilbara.
But unions and workers are worried about Fortescue's serious incident rate and some of the practices among its contractors.
Mine inspectors are carrying out multiple investigations into two deaths at Fortescue's Christmas Creek mine over the past six months and four incidents at the company's Solomon hub this month.
Mineral Resources Limited, the mining services company which employed a worker who died at Fortescue's Christmas Creek mine in August, said on Friday that Fortescue paid $300 million to buy out its two crushing plants as it hired its local workforce.
Mineral Resources' subsidiary Crushing Services International (CSI) employed more than 121 contractors at Christmas Creek when New Zealander Kurt Williams, 24, was crushed to death while carrying out maintenance work in the crushing plant.
Since then Fortescue's safety record has come under increased scrutiny.
Two weeks ago a 33 year-old man died while carrying out maintenance on a large piece of mining machinery at Christmas Creek's heavy vehicle workshop, prompting the mining regulator to issue a special order to improve safety procedures at the mine.
The man was employed by contractor Global Surface Mining.
At the time the WA Department of Mines and Petroleum (DMP) suspended operations and ordered Fortescue to improve its safety procedures at all of its operations.
The DMP is carrying out two separate investigations at Christmas Creek. It follows an incident last year in which a contractor had his leg amputated after a truck crash on a Fortescue site.
The department is also investigating incidents at Solomon in which three people were within a blast exclusion zone, two water truck incident reports, and an incident involving a tool carrier.
"Any incident is of concern and mine operators across WA's resources sector should always be looking to maintain and improve safety outcomes," the department's executive director of mine safety Simon Ridge said.
Mr Ridge has said Fortescue's mine sites appeared to have involved an "ineffectual isolation and lock out/tag out process".
Unions have highlighted Fortescue's use of contractors and say the safety culture has to change to prevent another death or serious injury.
"We want the full gamut of potential contributing factors to be examined in detail, including the replacement of experienced workers with cheaper alternatives," CFMEU Construction Division WA secretary Mick Buchan said.
Union members were very concerned about the serious incident rate at Fortescue Metals sites.
"Something's got to give otherwise there's just going to be more of the same."
Electrical Trades Union WA secretary Les McLaughlan has raised concerns about Crushing Services International's safety practices as employees worked on live equipment.
Meanwhile, mining services contractor Global Surface Mining, which employed the worker who died on December 30, is staying tight lipped about its current contract with Fortescue.
Fortescue is reviewing safety procedures and this week said it bought out CSI's equipment to ensure the "safe and efficient operation" of the two ore processing facilities.
"This outcome will assist in ensuring cultural alignment among the valued personnel," Fortescue chief executive Nev Power said in a statement.
Mr Power has previously said no one on a Fortescue site was expected to do anything that compromises safety.
A Department of Mines and Petroleum spokesperson says more than 500 workers per year suffer serious injuries on WA mines.