Rio Tinto apologises for losing highly radioactive capsule

Rio Tinto has apologised for losing a highly radioactive capsule that fell off a truck on a 1,400-kilometre stretch of desert highway in Western Australia, as the mining company sought to limit the damage from the incident.

The miner and Australian authorities are scrambling to find the missing part from a sensor used in mining, which measures just 6mm by 8mm and was lost on its way from a site in the Pilbara region to a depot in the state capital of Perth.

The silver capsule contains a small amount of caesium-137, and is dangerously radioactive. An hour of exposure from about a metre away is the equivalent of having 10 X-rays, and prolonged contact can cause skin burns, acute radiation sickness and cancer, experts said.

Rio’s role in the radioactive hunt across such a long stretch of the state is the latest episode for a company that is still trying to repair its reputation after the destruction of a 46,000-year-old Aboriginal heritage site at Juukan Gorge in Western Australia in 2020, which ultimately led to the exit of its then chief executive and chair.

In the past year it has issued a report that showed systemic levels of sexual harassment, bullying and racism at its mine sites. It also suffered a blow in its lithium ambitions after the Serbian government knocked back its licence to develop a $2.4bn mine in the country owing to strong environmental and public opposition to the project.

The search for the missing capsule has involved people scanning for radiation levels from the device along the vast trucking route. The device had been used at the Gudai-Darri mine to measure the density of iron ore feed.

Simon Trott, the head of the iron ore division who was appointed shortly after Danish finance director Jakob Stausholm became Rio chief executive in 2021, apologised for the “alarm” that had been caused.

“We are taking this incident very seriously. We recognise this is clearly very concerning and are sorry for the alarm it has caused in the Western Australian community,” Trott said in a statement on Sunday.

The mining company uses SGS Australia, the local subsidiary of Swiss-based testing business SGS, to specially package and handle the device given its radioactive element.

The component was being transported to an SGS laboratory in Perth by a separate logistics company and an investigation would determine how the component was able to come loose during the process, Rio said. A Geiger counter had been used to confirm the capsule was inside the package before it left the site.

Western Australia emergency services have called on other Australian states and the federal government for support in finding the capsule as they lack equipment.

Dr Andrew Robertson, chief health officer at the Government of Western Australia Department of Health, urged people not to touch the capsule. “Exposure to this substance could cause radiation burns or severe illness — if people see the capsule or something that looks similar, stay away from it and keep others away from it too,” he said.

SGS was not immediately available for comment.