Chambati, Y, Green, M, Watson, B & Andrews, PG 2024, 'Seismic monitoring of crush pillar behaviour in a deep-level gold mine using active sources', in P Andrieux & D Cumming-Potvin (eds), Deep Mining 2024: Proceedings of the 10th International Conference on Deep and High Stress Mining, Australian Centre for Geomechanics, Perth, pp. 417-428, https://doi.org/10.36487/ACG_repo/2465_22
(https://papers.acg.uwa.edu.au/p/2465_22_Chambati/)
Abstract: Gold Fields, South Deep Gold Mine uses crush pillars in their deep-level operation to support de-stress stopes. There was a concern about the ability of these pillars to withstand dynamic closure due to seismic events that are common at that depth. A study was conducted at approximately 3,000 m below the surface to determine the dynamic behaviour of these pillars. This paper describes active seismic source monitoring that was used to determine changes that developed within the pillar during a seismic event. The results showed that the crush pillar responded dynamically to large events, even when fully formed. These seismic events induced large decreases in seismic velocity measured using active sources. These drops were followed by a characteristic post-seismic relaxation, indicative of material damage followed by gradual healing. No evidence of permanent ‘damage’ was observed; however, no very large (moment magnitude greater than 2) seismic events occurred during the monitoring period.

Keywords: crush pillar, seismic, deep mine, de-stress, rockbursts