Rio Tinto apologises as search for radioactive capsule continues

Parts of Western Australia are on radiation alert after a tiny capsule containing cesium-137 was lost.

Mining giant Rio Tinto has issued an apology as the search continues for a tiny radioactive capsule that went missing when it was being taken to a storage facility in Perth, sparking a radiation alert in parts of Western Australia.

The silver-colored capsule, just 6 mm (0.24 in) wide and 8 mm (0.31 in) long, was lost while being mined from Rio Tinto’s Gudai Darri mine near Newman in the remote Kimberley Region was transported to a warehouse for about 1,400 pieces km (870 miles) away in Perth.

It’s unclear how long the tiny capsule containing cesium-137, a radioactive isotope that emits radiation at the rate of 10 X-rays per hour, will be missing.

The capsule left the site on January 12, and Rio Tinto’s contractor informed the company on January 25 that it was missing. The public was alerted two days later.

Rio Tinto said it takes the disappearance very seriously.

“We recognize that this is clearly a matter of great concern and we apologize for the alarm it has caused in the Western Australian community,” Simon Trott, head of Rio Tinto’s iron ore division, said in a statement Monday.

“Rio Tinto has engaged a third party with the appropriate expertise and certification to securely package the device in preparation for off-site transportation prior to receipt at its Perth facility,” he said, adding that Rio is also conducting its own investigation how the loss came about.

Before the device left the site, a Geiger counter was used to confirm the presence of the capsule in the package, Rio Tinto said. The authorities assume that the device fell out of the truck during transport.

“We conducted on-site radiological surveys of all areas where the equipment had been located and surveyed roads inside the mine site and the access road leading away from the Gudai Darri mine,” said Trott.

Authorities have recommended people stay at least five meters (16 feet) apart and a radiation alert remains in place in parts of the vast state.

Health officials have warned that handling the capsule could cause radiation burns or nausea.

“The concern is that someone will pick it up without knowing what they’re dealing with,” said Dr. Andrew Robertson, Chief Health Officer for Western Australia.

The capsule is packed in a box bolted to a pallet, in accordance with transport and radiation protection regulations, he added.

“We think the vibration from the truck may have compromised the integrity of the gauge that it fell apart and the source actually came out of it,” Robertson said. “It’s unusual for a gauge to fall apart like this.”

The state’s Department of Fire and Emergency Services deployed teams with handheld radiation detectors and metal detectors along a 36 km (22 miles) busy cargo route to search for the container.

“What we don’t do is try to find a tiny little device by sight,” Superintendent Darryl Ray said, adding that they were focusing on populated areas north of Perth and strategic locations along the Great Northern Highway.

“We use the radiation detectors to locate the gamma rays,” he said.

Authorities are also using the truck’s GPS data to determine the exact route the driver took and where he stopped after exiting the mine. It arrived at the Perth depot on January 16th.

There are concerns that it may have become lodged in the tires of a vehicle traveling on the same road.