The Athabasca Basin in the Canadian Shield is a stark and rugged wilderness that harbours the world's leading source of high-grade uranium. It is challenging terrain, remotely located, and generally inhospitable to those who visit. For one geophysicist deployed in the area, however, the striking landscape served as inspiration for an idea that would change my personal and professional trajectory.
Brian Powell was working for Cameco in the mid 2000s and had read about the experimental use of cosmic-ray muons to radiograph objects and geological structures1. Muons are a naturally occurring sub-atomic particles produced by cosmic rays striking the Earth’s atmosphere. These rays are not harmful to us or any other life on the surface of Earth, but they bombard us on average about once per minute for every square centimetre. As they pass through the Earth’s surface, muons lose energy progressively. More importantly, as they encounter higher-density material, they lose energy at an accelerated rate, which reduces their intensity. This intensity, and thus the density of the materials encountered, can be measured and used to identify and characterize objects and anomalies.
Brian wondered whether muon imaging could be used for subsurface exploration in areas like the Athabasca Basin, so around 2006, he called up the research team at TRIUMF – Canada’s national particle accelerator centre. Founded in 1968, TRIUMF is a collaboration of more than 20 Canadian universities driving innovation in isotope science and particle physics. Turns out they didn't know the answer to his question... but they were interested enough to start exploring the potential.
Over the next few years, muon tomography2 techniques were researched, developed, tested, and proven in the field to be very effective for subsurface mineral exploration. The unique straight-line imaging technique delivers unparalleled location accuracy with higher spatial resolution (< 10m) than other geophysical survey tools. Much like medical tomography, which images the interior of the body clearly using x-rays, muon tomography images what lies beneath our feet – up to 1 km deep.
Around this time, I was wrapping up my post-doctoral research at TRIUMF, chasing down the Higgs boson with the Large Hadron Collider at CERN. I knew about the muon project through an officemate but got more intrigued as I learned about the research underway. By this time, a new company (CRM Geotomography Technologies) had been created to advance the imaging solution towards commercialization, and a blind trial was underway with a major mining company. It was a great time for a new adventure.
The blind trial went quite well, but the major challenge was that the first-generation muon imaging device was about the size of a kitchen table and as heavy as a small car. Our partners were pleased with the imaging capabilities but found the units cumbersome to transport and difficult to install. Further, the form factor meant that the technology could only be used where there were underground workings. The challenge was to miniaturize the technology so that it could be deployed easier and more cost-effectively, and develop inversion techniques to combine muon tomography data with other data sources.
In 2018, I wrote about early case studies of muon tomography for the CSEG Recorder. Since then, we have successfully reduced the scale of the muon detectors by 50x, developing a 3m x 89mm cylinder that can be deployed down industry-standard boreholes. Combined with proprietary algorithms and advanced inversion technologies, the platform will allow for the combination of muon data with drill assay, gravimetry, and other geophysical data to enhance the characterization of subsurface geology. Applying artificial intelligence techniques will soon facilitate the incorporation of all available geoscience datasets – often collected but rarely used.
In the middle of the 2020 pandemic, CRM Geotomography Technologies became Ideon Technologies and closed $1.3 million in seed funding to fuel our path to market in 2021. For us, this journey is not just about providing a more effective way to image the subsurface – it is about accelerating the world’s transition to low-impact mining. Our vision is that by enabling mining companies to see the unseen, effectively creating a digital twin of the subsurface, we can deliver a 95%+ quantifiable certainty of discovery in an environment that has traditionally been very uncertain. By doing this we will help companies drill less and discover more, reducing environmental impact and improving operational efficiencies across the system so they can extend life-of-mine and deliver on their goals.
Sadly, I never met Brian as he passed away before the research proved the validity of his idea. We speak of him often when we introduce our vision, acknowledging the true spirit of exploration and curiosity that gave rise to the work we’re doing today. It seems fitting somehow that we will lead an international collaboration to deploy the world’s first borehole muon detector this spring – in the Athabasca Basin.
1The first recorded use of muon-based geophysics was by E. P. George in the 1950’s, who used muon attenuation to infer the average overburden of material above a railway tunnel. The famous physicist Luis Alvarez used muon attenuation to search for hidden chambers in an Egyptian pyramid (in that case, the search was for an enhancement of the muon flux due to a chamber filled with air instead of rock).
2Tomography is imaging by sections or sectioning through the use of any kind of penetrating wave.
About the Author(s)
Doug Schouten is CTO and Co-founder of Ideon Technologies. He is a global leader in muon tomography and one of the few people in the world with the expertise to turn muon research into industrial problems solved. Doug holds a BSc. (Hons) in physics and computer science from UBC, and a PhD in subatomic physics from SFU. Doug also has extensive expertise in computer simulation, data analysis and statistical inference – including machine learning methods and detector physics.