Authorities confirmed on Feb. 1 that they had “essentially found the needle in the haystack” after the piece—which emits approximately the same radiation as 10 X-ray blasts—was located two meters off the Great Northern Highway in Pilbara, 74 kilometers south of Newman.

The piece is used as a density gauge by mining giant Rio Tinto and was collected from its Gudai-Darri mine on Jan. 12. It was reported missing on Jan. 25 when its package was opened at a secure storage facility and pieces that had been packed were not found inside. 

A major search was launched for the small silver capsule—which is eight millimeters high by six millimeters round—led by the Department of Fire and Emergency Services.

Fire and emergency services commissioner Darren Klemm noted: “When you consider the challenge of finding an object smaller than a 10-cent coin along a 1,400-kilometer stretch of Great Northern Highway, it is a tremendous result. 

“I want to thank everyone involved in the search. We called on a large number of agencies to assist, and this was a great example of working together to achieve an outstanding result.”  

Western Australia’s chief health officer, Dr. Andrew Robertson, said it was a “great result” and said the chances of anyone being contaminated by the source were extremely remote: “As I have mentioned previously, to be at risk of radiation exposure you need to be close to the source for a period of time.

“If you were one meter away from the source for one hour, that would be the equivalent of receiving the radiation dose of 10 X-rays.”

The capsule was safely recovered and is being transported to Newman in a lead container for secure storage. It will then be taken to a Western Australia health facility in Perth.

How did they find it?

Klemm said that a specialist detection vehicle was traveling at 70 kilometers per hour when its equipment picked up radiation emitted by the capsule.

A search team then used portable detection equipment to locate the capsule, and the Australian Defense Force verified the capsule using its serial number.

The site will be surveyed to ensure there is no contamination in the surrounding area. Klemm added it was “extremely unlikely” that this will be the case, but added that should any issues arise authorities will “remediate” the area.

He said: “You can only imagine it’s a pretty lonely stretch of road out there. A lot of work went into searching the metro area based on some intelligence early on, so you can’t help but imagine there was an element of surprise when the equipment spiked up.

“It’s certainly the best possible outcome in terms of the space where it was found. There’s been much discussion working through the possible outcome that we wouldn’t find it, and given the fact that it could’ve been anywhere from the mine to the metro site, this could possibly be the best area. And to do it in such a short period of time is simply amazing.

“There was always a sense that we were going to find it; it was just exactly how long, and the worst possible outcome was that we’d still be here in 12 months’ time.”

What has Rio Tinto said?

Simon Trott, the company’s iron ore CEO, previously told Fortune it had launched an investigation into how the capsule came to be lost.

He said: “Rio Tinto engaged a third-party contractor, with appropriate expertise and certification, to safely package the device in preparation for transport off-site ahead of receipt at their facility in Perth. Prior to the device leaving the site, a Geiger counter was used to confirm the presence of the capsule inside the package.  

“As well as fully supporting the relevant authorities, we have launched our own investigation to understand how the capsule was lost in transit. As part of this investigation we are working closely with the contractor to better understand what went wrong in this instance.”