Muon Tomography for Improving Outcomes in Mining

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.

Speaker: Doug Schouten, Ideon Technologies and Simon Fraser University