Transformative muon technology deployed at McClean Lake

Muon tomography uses muons - naturally occurring subatomic particles created when cosmic rays enter Earth's upper atmosphere - to provide x-ray-like imaging up to 1 km beneath the Earth's surface. This means that new mineral and metal deposits can be identified with precision and confidence, with less need for drilling, reducing costs and risks, saving time and minimising environmental impact.

Ideon - a spin-off of Canada's TRIUMF national particle accelerator laboratory - has developed a discovery platform which integrates proprietary muon detectors, imaging systems, inversion technologies, and artificial intelligence to produce high-resolution 3D density maps of underground targets. The company has been working with Orano since 2016, when its first-generation large format detectors were used to image a high-grade uranium deposit under 600 m of sandstone at the McArthur River mine.
 
A miniaturisation effort has led to the development of the first industry-standard borehole (less than 10 cm in diameter), low-power (less than 10W continuous power consumption), zero-maintenance muon tomography detector suitable for operation in the extreme environmental conditions of mineral exploration sites around the world. Its deployment is a milestone that has taken more than a decade to reach, Ideon CEO Gary Agnew said.

Deploying the detector in the borehole (Image: Ideon)
"We've spent seven years doing commercial trials in partnership with the mining industry and several years of system design and development, de-risking and prototyping in the lab," he said. "Orano has been there right along with us for much of that journey, leading the way as a customer-driven innovator in the global energy transition. We are grateful for their enthusiasm, flexibility, trust, and willingness to break new ground with us."

Hervé Toubon, R&D and innovation director at Orano Mining, said the company expects the project to "transform the very nature" of exploration. It is "virtually impossible" to detect high-grade deposits at depth using traditional geophysical exploration techniques, he said. "The subsurface intelligence we gain with muon tomography gives us the ability to accurately locate those anomalies while reducing the need for drilling and lowering our overall environmental impact. That value proposition is hard to beat."

Orano's imaging target is a high-grade, compact uranium deposit located at a depth of 300 m. Multiple borehole muon detectors are deployed down a single drill hole in a connected sequence, delivering progressive imaging results throughout the survey. The McClean Lake project, which is approved by the Eureka intergovernmental R&D funding and coordination organisation, is receiving advisory services and funding support from the National Research Council of Canada Industrial Research Assistance Program and will run until the end of 2021.

In addition to muon tomography models, Ideon said it will also work with Orano to develop joint inversions with existing drill data and other geophysical datasets.

Muon detection systems have also been used to investigate passively the contents of legacy waste containers at Sellafield in the UK and to investigate the location of molten fuel within the damaged reactors at the Fukushima Daiichi plant in Japan.