Abstract
As the demand for mineral resources is on the rise and mining operations continue to dig deeper at higher mining rates, the risks associated with mining-induced seismicity have substantially increased. Strong seismic events can cause rock mass and support system damage in drifts and stopes, resulting in production delays; more importantly, they may pose a hazard to the safety of mine operators. Thus, the causes and risks associated with mining-induced seismicity must be investigated. This paper reports on the results of a case study at Young-Davidson (YD) mine in Canada. The YD mine is experiencing large seismic events at different mining horizons. The focus of this study is the MW2.0 events occurring in the lower mine in the depth range of 900 to 1,200 m below surface. The goal is to identify the root causes behind the large seismic events and suggest remedial strategies. The analysis of seismic source parameters and moment tensor inversion of five large seismic events helped identify the source mechanisms. In situ stress measurements previously conducted at the YD mine were analysed and used in a mine-wide numerical model that was generated with FLAC3D, taking into consideration the northeast-trending diabase dykes. The model simulates mining-induced stress distribution following the mine plan of primary and secondary stope extraction. Qualitative assessment of the safety factor, brittle shear ratio and stored strain energy, as well as comparison with seismic source location, magnitude, and mechanism, helped provide an understanding of the seismic behaviour in the lower mine.
The study revealed that strong seismic activities are attributed mainly to high pre-mining differential stress ( with running parallel to the dykes. This leads to high differential stress build-up in the secondary stopes (ore pillars) and sill pillars, which causes predominantly compressive/shear seismic source mechanisms. The research completed by Khalil (2023) forms the basis of this paper.
Authors:
Heba Khalil (Presenter) | SRK Consulting (Canada)
Andy Thomas | SRK Consulting (Canada)
Tuo Chen | McGill University, Canada
Hani S Mitri | McGill University, Canada
Travis Blake | Alamos Gold Inc., Canada
Click here to view all presentations at this event
