When mining giant Rio Tinto reported on January 25 that one of their radioactive Caesium-137 capsules had vanished, Western Australian authorities were faced with what seemed to be an insurmountable assignment.
From the Gudai-Darri mine in the state’s north to a depot just north of Perth’s downtown, they had to find a pea-sized capsule anywhere along a 1,400km (870 mile) trip.
Authorities acted quickly, mobilizing specialized search crews to look for the capsule. Firefighters were among those requested to divert from their regular summer duties to assist in the search.
Experts from all throughout the nation were consulted, including representatives from the emergency management organization, nuclear science, and radiation protection.
According to authorities, the capsule fell off a radiation gauge that was being moved on January 12 from a Rio Tinto mine site to a storage facility in Perth’s northeastern suburbs.
They hypothesized that the fasteners may have fallen free due to vibrations during transport, causing the capsule to fall through cracks in the truck’s casing.
To estimate the density of particular materials, caesium-137 (Cs-137) capsules are frequently employed in radiation gauges in the mining industry. However, if you come into contact with one, you could sustain severe burns and be exposed to 10 x-rays an hour.
On January 26, authorities started searching around Perth and the area near the mine site in Newman before alerting the public to the hazard.
To alert the public to the danger the radioactive capsule poses, an urgent health warning was released on January 27. Health officials issued a clear warning to anyone who might encounter it: Stay away.
Chief Health Officer of the state Andy Robertson cautioned: “It produces both beta rays and gamma rays so if you have it close to you, you might either end up with skin harm including skin burns.”
Authorities were worried that it might have gotten stuck in a passing car’s tire.
Search teams were actively seeking for the small capsule by January 27. However, they were utilizing portable radiation survey meters rather than their eyes to look for it.
Within a 20-meter radius, the survey meters are intended to detect radiation.
“We are not attempting to locate the little capsule using our vision. Hopefully, the radioactive equipment will help us find it “The next day, a police spokeswoman made a statement.
Police concentrated their search on the GPS route the vehicle had travelled and on locations near Perth’s high-density and urban districts.
On January 28, after a member of the public saw unusual activity on a Geiger counter, a gadget used to measure radiation, police prioritized one spot along the Great Northern Highway.
But the capsule was not found during that search.
The following day, the Australian federal government had granted the request for further resources, and those in charge of the search started organizing its next stage.
The search was intensified after the new equipment arrived in Western Australia and was prepared for operation by January 30.
Darryl Ray, an incident controller with the state’s emergency services division, only referred to the new government-provided equipment as “specialized radiation detecting equipment” when describing it.
The gamma-ray spectrometer and radiation portal monitors were two of the new tools being utilized by the search teams, according to local media.
Airports frequently employ radiation portal monitors, which can detect gamma radiation and scan passengers to check for the presence of radioactive materials. Gamma spectrometers calculate the radiation’s intensity.
According to Mr. Ray, the new detection technology might be mounted on automobiles, enabling searches to be conducted while the vehicles are traveling at a speed of roughly 50 km/h.
The crews will proceed north and south along the Great Northern Highway for around five days to complete the estimated 1400 kilometer original route, he said.
But as of the end of January 31, the capsule was still eluding search teams.
The Department of Fire and Emergency Services stated, “More than 660km has been searched so far – thank you to all departments for their cooperation.”
It looked all but impossible had been accomplished the following morning when the government announced the capsule had been discovered just two meters off the side of the road at 11:13 local time on Wednesday.
Search teams have “very literally found the needle in the haystack,” according to the authorities.
At a press conference on Wednesday, Fire and Emergency Services Commissioner Darren Klemm stated, “You can only imagine it’s a fairly lonely stretch of road from Newman down to Perth.”
“You can’t help but think that when the equipment did spike up, the occupants in the car were a little taken aback.”
Mr. Klemm was reticent to reveal the precise site where the radioactive capsule was discovered, but he called it “the finest conceivable conclusion.”
According to local media accounts, it was discovered about 74 kilometres from Newman, or 200 km away from the mine site.
Authorities said that no one appeared to have been hurt by the capsule, and it didn’t appear to have moved from its initial location.
According to Mr. Klemm, the federal government’s increased resources were crucial in helping to locate the capsule.
He said that a car traveling by at 70 km/h discovered it thanks to the survey equipment employed from the beginning to detect radiation and the specialized equipment that really located the capsule.
The capsule’s serial code was verified to be the correct one.
The discovery was hailed as a “win for science” by Curtin University Associate Professor Nigel Marks of Western Australia.
Since it produces gamma radiation, it makes sense to search the roadside for anything with a significant gamma signal, and sure enough, that’s where they discovered it.
Dr. Marks continued by saying that most lost “orphan sources”—self-contained radioactive materials—are rarely found again.
Unbelievably many of these sources that go lost are never found, he claimed.
“It’s a regulatory mistake, but I believe how they discovered it is pretty fascinating,” the speaker said.
The chair of Australia’s Radiological Council will now look into the specifics of how the capsule originally went missing.
The report’s findings will determine whether Rio Tinto will face charges.
Simon Trott, the CEO of Rio Tinto, announced the business will “completely cooperate” with the investigation when the capsule was discovered.
He added that if the government ordered the search, Rio Tinto would pay for it.