Abstract:

Cosmic‑ray muon tomography provides a passive, high‑penetration imaging modality capable of resolving subsurface density distributions at depth and in complex geological environments. Muons—secondary particles generated by cosmic‑ray interactions in the upper atmosphere—propagate along near‑straight trajectories and lose energy in proportion to the integrated density of the material they traverse. By measuring directional muon flux using borehole‑deployed or underground tracking detectors, the technique enables construction of radiographic datasets that can be inverted to recover 3D density models. Recent advances in inversion methodology, including probabilistic forward modelling and joint interpretation with complementary geophysical data, have substantially improved resolution, uncertainty quantification, and robustness of geological interpretations.

We illustrate these developments through three case studies. At Fireweed Metals’ Macmillan Pass project, muon tomography integrated with gravity and downhole datasets delineated mineralized structures at hundreds of metres depth, reducing ambiguity in drill targeting. At BHP’s Olympic Dam, muon measurements demonstrated sensitivity to large-scale density contrasts in a deep, active mining environment, informing resource characterization workflows. At Evolution Mining’s Northparkes operation, repeated deployments enabled tracking of density variations associated with cave propagation, supporting geotechnical understanding in a block‑cave setting.

Together, these examples demonstrate how muon‑physics‑based imaging and modern inversion approaches provide a high‑confidence, high‑resolution foundation for subsurface decision‑making across exploration, resource delineation, and mining operations, reducing environment impact and cost.

Bio:

Doug Schouten, PhD

Co-founder & CTO, Ideon Technologies

Adjunct Professor of Physics, Simon Fraser University

Doug has over a decade of experience in the mining industry after completing a PhD and post-doctoral fellowship in subatomic physics, focused on the discovery and characterization of the Higgs particle with the Large Hadron Collider at CERN.  Doug has led foundational applied research programs in subsurface imaging using cosmic ray muon tomography, and has also led development of MEMS gravimeter systems, unique AI and data inversion algorithms, and other novel sensors – and applied these in successful pilots through to commercial implementation at mine sites and exploration projects around the world, driving production efficiency, time savings and safety improvements. He has published hundreds of peer-reviewed scientific papers, and is the inventor for more than 10 patent families in the US and globally. Doug continues to review papers for leading geophysics journals, and also serves in an advisory capacity for a variety of startups and scientific initiatives ranging from astrophysics to mining. He is highly motivated to bring useful technological innovation to the mining industry, driving improved environmental and social stewardship, profitability, and helping to drive a positive feedback loop that attracts top technical minds to the industry.