Analysis of a Large Rock Slope Failure on the East Wall of the LAB Chrysotile Mine in Canada: Back Analysis, Impact of Water Infilling and Mining Activity

Abstract

A major mining slope failure occurred in July 2012 on the East wall of the LAB Chrysotile mine in Canada. The major consequence of this failure was the loss of the local highway (Road 112), the main commercial link between the region and the Northeast USA. LiDAR scanning and subsequent analyses were performed and enabled quantifying the geometry and kinematics of the failure area. Using this information, this paper presents the back analysis of the July 2012 failure. The analyses are performed using deterministic and probabilistic limit equilibrium analysis and finite-element shear strength reduction analysis modelling. The impact of pit water infilling on the slope stability is investigated. The impact of the mining activity in 2011 in the lower part of the slope is also investigated through a parametric analysis.

Tsunami generation by potential, partially submerged rockslides in an abandoned open-pit mine: the case of Black Lake, Quebec, Canada

“…3) was deducted based on mining company information, and no boring was made for this particular project in order to confirm this geological model. The results show that with geotechnical parameters reported in table 1 which are average values derived from rock mass characteristics provided by several modelling, laboratory testing and field measurement sources (see Grenon et al 2017 for all the details) and with cohesionless material (assumption reasonable given the actual large displacement of the failed mass), the factor of safety would be about unity when the water level is at an elevation of 45 m below sea level, i.e. when the pumping of the water by the mine was still active and the open pit was free of water.…”

“…Some of these more sophisticated models include Flow-3D which has already been used to reproduce physical model experiments (Basu and al. 2009), OpenFOAM which was used to model landslide on river banks that generated tsunami (Locat et al 2017), Fluent (Biscarini 2010) that was used to simulate the 1958 Lituya bay tsunami in a 2D simplified geometry or Smoothed particle hydrodynamics (SPH) codes that were also used to replicate laboratory experiments (e.g. Yeylaghi et al 2017).…”

“…Slope stability analysis previously carried out by Grenon et al (2017) andin Turmel et al (2016) analyses were used to define the volume and geometry of potential landslides. Geotechnics parameters were obtained with a back analysis of the July 2012 rockslide case on the open-pit east wall and by the use of informations provided by the mine.…”

Analysis of the influence of groundwater and the stress regime on bolt behaviour in underground coal mines

“…The software includes steady-state, finite element groundwater seepage analysis to which pore pressure, flow and gradient can be determined along with effective stress. The software has been previously adopted to perform numerical modelling in numerous studies (Coggan et al 2012;Coli et al 2008;Day et al 2017;Grenon et al 2017;Perras and Diederichs 2007;Sasaoka et al 2016;Smith 2016;Winn et al 2017;Zsaki 2010). RS 2 (Phase 2 9.02) was selected for the study given finite element capability, user friendly interface and relatively simple application.…”

Deterministic and probabilistic stability analysis of a mining rock slope in the vicinity of a major public road — case study of the LAB Chrysotile mine in Canada

“…The estimated displaced volume was 5.0 × 10 7 m 3 . This failure is documented extensively in Grenon et al 2016. These references also present a detailed back-analysis of the east wall failure.…”