Monitoring and numerical modelling of induced and triggered seismic activity in a deep sublevel-stoping mine

Abstract : The Garpenberg undergroung mine (Sweden) is a non-ferrous metal mine, owned by Boliden company. It is exploiting lead, zinc and copper, together with minor amounts of silver and gold. The study area of the ongoing research work is part of the Lappberget orebody: an almost vertical deposit, which is mainly exploited by the sublevel stoping method, with backfilling, down to 1300 meters depth. A microseismic monitoring network, constituted by both 1-component and 3-components geophones, was installed in this area of the mine in the end of 2014 by Ineris. Recorded microseismic activity until December 2016 shows a good correlation with mining excavations, but also triggered seismic events, which are influenced by the presence of weak rock lenses within the stiff rock masses. A 3D elasto-plastic numerical model was run with the code FALC-3D, considering a precise reconstruction of the geology, the virgin stress state and the mine voids. The model takes into account 70 excavation steps, which correspond to the drifts developed and the stopes produced in the study area between 2014 and 2016. The results show how the mining sequence, with one column of stopes being exploited upwards and downwards simultaneously, leads to high stress concentrations and to strong plastic deformation within the weak rocks. Finally, we investigated possible statistical correlation between observed microseismic data (moment magnitude, seismic energy and corner frequency) and computed mechanical parameters (elastic and plastic deformation increments, Von-Mises stress jumps, released energy, etc.) by means of principal component analysis, helping to identify and analyze possible seismicity-triggering phenomena.
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Conference papers
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https://hal-ineris.archives-ouvertes.fr/ineris-01853364
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Submitted on : Friday, August 3, 2018 - 10:14:11 AM
Last modification on : Friday, April 5, 2019 - 8:21:42 PM

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  • HAL Id : ineris-01853364, version 1

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Francesca de Santis, Yann Gunzburger, Vincent Renaud. Monitoring and numerical modelling of induced and triggered seismic activity in a deep sublevel-stoping mine. Séance technique CFMR "Apport de la mécanique des roches à l'exploitation minière", May 2018, Paris, France. ⟨ineris-01853364⟩

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