Recent Advances in Fiber Optic Sensing for Geotechnical Monitoring: Practical Considerations for the Mining Industry

ABSTRACT: The safety of tailings dams and auxiliary mining infrastructure requires monitoring solutions capable of detecting relevant geotechnical performance indicators. Recent advances in the fibre optic sensing technology of distributed acoustic sensing (DAS) enable continuous dynamic strain measurements over long distances (i.e., tens of kilometers) with meter-scale spatial resolution. This presentation provides practical perspectives on considerations for DAS within the mining industry, illustrated with two recent studies. In the first study, four months of DAS observations at a northern Canadian tailings facility were used to infer changes of shear-wave velocity inside the dam, relying on energy from the ambient seismic wave field. As shearwave velocities can be used as a proxy for soil stiffness, this method helps understand changes in tailings dam performance. The second study involved three-day DAS recordings at a slow-moving landslide observatory in the United Kingdom. Here, lowfrequency (<1 Hz) DAS measurements revealed near-surface slope failure processes with unprecedented nanostrain-rate sensitivity and spatiotemporal resolution. The results capture rupture zone initiation, retrogression, and flow-lobe activity. While these results demonstrate how geotechnical parameters can be derived from DAS data, key challenges remain. These include limited knowledge about instrument response and cable coupling, environmental effects and the management of large data volumes. This presentation will explore practical strategies to overcome these challenges, needed to support broader adoption of DAS technology in the mining sector.