Kalenchuk, KS, Mercer, R & Williams, E 2017, 'Large-magnitude seismicity at the Westwood mine, Quebec, Canada', in J Wesseloo (ed.), Deep Mining 2017: Proceedings of the Eighth International Conference on Deep and High Stress Mining, Australian Centre for Geomechanics, Perth, pp. 89-101, https://doi.org/10.36487/ACG_rep/1704_04_Kalenchuk
(https://papers.acg.uwa.edu.au/p/1704_04_Kalenchuk/)
Abstract: The Westwood mine is located approximately 40 km east of the town of Rouyn-Noranda and 80 km west of the town of Val-d’Or in Quebec, Canada. Operations at the Westwood mine were halted by three largemagnitude seismic events which occurred over two days in May, 2015. This paper provides an overview of the seismic events and summarises the numerical back-analyses completed using global minescale and local drift-scale models, to gain an understanding of the mechanisms that fundamentally contributed to what was considered, by a review panel of experts, to be an unforeseen series of events. A global mine model was required to provide a reasonable estimate of the induced stresses on nearfield pillars and excavations and a detailed small-scale model was necessary to adequately capture the failure mechanisms in drift ribs, which played a role in sublevel pillar performance. The global model did not provide sufficient resolution to capture drift-scale mechanisms. While the local model was insufficient for calibration of the mine system boundary conditions, the combination of global and local models is valuable in defining mine-scale stress conditions and their impact on local, drift-scale failure mechanisms.


Keywords: numerical modelling, pillar stability, rockbursting