Challenge

Cave mining deliberately induces large‑scale rock mass failure, creating rapidly changing stress and strain conditions around the cave that are difficult to observe directly. At a copper-gold mine, existing monitoring techniques provided valuable but incomplete insight, often offering indirect or delayed indications of rock mass response. This made it challenging to detect subtle precursors to cave propagation and deformation, and to provide mine operators with timely, objective data to support safe access and operational decision‑making near high‑risk cave zones. 

Solution

To address this gap, the project implemented a distributed fibre‑optic sensing (DFOS) solution to directly measure strain along continuous lengths of optical fibre installed in boreholes around the cave. The fibre‑optic system delivered continuous, high‑resolution measurements of rock mass deformation over hundreds of metres, providing near real‑time visibility of how stress and strain evolved as the cave propagated. This data enabled mining and geotechnical teams to clearly identify zones of yielding rock and track cave growth. In the future, strain measurements could be integrated into operational risk management processes, complementing seismic and other monitoring systems with a level of spatial detail and continuity that was previously unavailable. 

Further information is available in this paper presented at the 2024 ACG Deep Mining conference: “Distributed fibre optic sensing for ground monitoring in underground hard rock mining”