Törnman, W, Martinsson, J, Bayar, E, Ulziijargal, M-E, Uranchimeg, B, Lilley, C, Davies, A, Amir, M & Svanberg, E 2026, 'Findings from large-scale distributed acoustic sensing monitoring 
of the Panel 0 block cave at Oyu Tolgoi', in A van As, D Cumming-Potvin & J Wesseloo (eds), Caving 2026: Proceedings of the Sixth International  Conference on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, pp. 1-15, https://doi.org/10.36487/ACG_repo/2645_86
(https://papers.acg.uwa.edu.au/p/2645_86_Martinsson/)
Abstract: This paper presents key findings from a large-scale deployment of distributed acoustic sensing (DAS) for seismic monitoring at an active block cave mine. The fibre-optic cables were installed in boreholes positioned to the side of the cave footprint to enable continuous monitoring of both strain and seismic activity throughout cave propagation. The system was designed to remain operational as the cave expanded, providing a rare opportunity to observe the evolution of seismic response in real time. The installation initially comprised 398 DAS channels, generating a large data volume that demonstrated the scalability and real-time performance of the processing software. Despite a suboptimal geometry for event location, with two nearly parallel boreholes, the end-to-end system successfully captured microseismic signals and located seismic events reflecting the stages of cave development. Using fibre optics also allows microseismic data to be integrated with strain and distributed strain sensing (DSS) measurements for enhanced interpretation. Overall, the study confirms that DAS is a viable and scalable tool for continuous, high-resolution seismic monitoring in block cave environments, and it highlights that sensor geometry should be carefully considered in the design phase to optimise event localisation and interpretive value.

Keywords: distributed acoustic sensing, block caving, microseismic monitoring, fibre-optic sensing, cave propagation, sensor geometry