Abstract
Cosmic-ray muons are charged elementary particles that arise naturally from cosmic radiation interacting with the Earth’s upper atmosphere. Particle showers of muons bombard Earth steadily and are attenuated by their interaction with matter along their trajectory. Muons can penetrate deep into the Earth’s crust, up to thousands of metres, and their attenuation in matter is proportional to the density of material the muon passes through.
By measuring muon flux through detectors positioned beneath the surface, the average density in the overburden within a wide field of view above the detector can be determined. Each detector produces a radiographic image of the rockmass in the wide field of view above it, and combining these images yields three-dimensional tomographic reconstructions of subsurface density.
Muon tomography-derived density models can be used in a wide variety of settings across the mining life cycle. Ideon Technologies has successfully deployed muon tomography to remotely monitor block cave propagation, ensuring continuous cave production and avoiding operational hazards while reducing geological uncertainty in understanding the rock volume surrounding the cave.
This presentation will present how muon tomography can be used to accurately delineate the ever-changing parameters of block cave edges, the growing air gap created, and the muck pile forming at the cave bottom. It will showcase results from the world's first muon tomography-based block cave deployments, demonstrating its power to delineate the full 3D extent of the cave, map heterogenous density variations in cave zones, and measure temporal changes in both rock flow and cave extents.