This study is a feasibility test to evaluate the use of Fibre Optics Sensing as a potential
solution for ground vibration monitoring during underground excavation with respect to
practical applications in mining activities including prediction of biotite containing
volumes ahead of the tunnel face. The Distributed Acoustic Sensing technology has high
potential also for other purposes, e.g., for infrastructure tunnel works. The quality of Fibre
Optics Sensing data as compared to other types of traditional seismic acquisitions is
investigated, as well as the operational benefits and constraints for the use of this
technology during rock characterization.

Several hundreds of meters of fibre optical cables have been installed between two mine
drifts, shotcreting the cables along the rock wall. The measurements on those cables have
been performed in two different monitoring experiments in 2022 and 2024. Two different
types of cables have been tested: a regular telecommunication cable and a more robust
armoured cable. Thus, the sensing performance of the two cables is analogous, the
armoured cable survived a local displacement due to an evident crack in the wall.
The project has been financed by BeFo with co-funding and in-kind from Lunds
university, LTH, LKAB, RISE and the University of Cagliari (Italy).
The reference group consisted of Fredrik Kullander, Björn Lund, Mats Svensson, Jennifer
Juslenius, Fredrik Nylén, Per Tengborg, and Patrik Vidstrand.

Stockholm
Patrik Vidstrand