2024 – Mapping of the Phreatic Surface in Tailings Dams with Muography

Mark A McLean, Federico Scutti, Ray Seikel, Alan R Duffy, Asbjorn N Christensen

Muon tomography is a promising technique for non-invasive imaging of geological structures, with applications in volcano monitoring and minerals exploration. In civil engineering, it shows potential for mapping critical features within tailings dams, especially the phreatic surface—the boundary between saturated and unsaturated zones crucial for assessing dam stability and seepage potential.

Unlike traditional methods that require drilling, muon tomography is non-invasive, minimizing disturbance to the dam and its surroundings. It provides volumetric images with meters-level spatial resolutions, enabling detailed characterization of subsurface features and small-scale heterogeneities. This continuous monitoring capability allows for repeated imaging to track changes in the phreatic surface and detect potential anomalies indicating dam instability.

This model study shows that the phreatic surface exhibits sufficient density contrast to be detectable by muon tomography, and a telescopic detector setup at 100m distance can map vertical variations with a 5m resolution. In conclusion, muon tomography offers a non-invasive, high-resolution solution for assessing dam integrity and seepage risk. As detector technology and image reconstruction algorithms advance, muon tomography is poised to significantly enhance dam monitoring and management.