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The Black Lake rockslide is located on the east wall of an open-pit mine initially operated by LAB Chrysotile near Thetford Mines, Quebec. Movements were observed in July 2012 when a volume of 2.0 x [10.sup.7] [m.sup.3] was mobilized, destroying a large portion of Highway 112. Mining operations ceased in 2012, causing the complete shutdown of the pumping system whose goal was to prevent the rise of water level in the pit. As the water level increases in the pit, it is essential to determine the potential of tsunami generation by possible partially submerged rockslides and to understand the potential impacts. A series of possible scenarios have been analysed with regard to velocity and acceleration of the potential rockslide as well as the corresponding wave generation and inundation. Results from the simulation show that when the factor of safety of the global slope is less than unity, inundation would not reach the potentially vulnerable infrastructures. Maximum wave height will vary as a function of the filling of the lake, and the lower wave height relative to water depth will happen when the lake is completely filled.Key words: landslide-generated tsunami, partially submerged landslide, numerical modeling, open-pit mine, active rockslide.Le glissement de Black Lake est situe sur la paroi est d'une ancienne mine a ciel ouvert exploitee par la compagnie LAB Chrysotile, a Thetford Mines, Quebec. Ce glissement actif a connu un fort episode de glissements en juillet 2012, ou un volume de 2,0 x [10.sup.7] [m.sup.3] a ete mobilise, emportant une large portion de la Route 112. Les operations minieres ont cesse en 2012, causant l'arret complet du systeme de pompage lequel visait a prevenir la montee du niveau d'eau dans la fosse. Comme le niveau d'eau augmente dans la fosse il devient primordial de determiner le potentiel tsunamigenique genere par des glissements rocheux partiellement submerges possibles afin de comprendre le phenomene et de reagir efficacement a celui-ci. Plusieurs modelisations numeriques ont ete realisees a partir de scenarios probables concernant les vitesses et les accelerations de glissement rocheux potentiel ainsi que la formation de vagues et l'inondation correspondantes. Les modelisations effectuees ont permis de montrer que, lorsque le facteur de securite de la pente globale est inferieur a 1, aucune infrastructure potentiellement vulnerable ne serait touchee par un eventuel tsunami. La hauteur maximale de la vague generee sera fonction de la hauteur d'eau dans le bassin. Les hauteurs de vagues minimales, relatives au niveau d'eau dans le bassin, seront generees lorsque le bassin sera completement rempli.Mots-cles: tsunami genere par un glissement de terrain, glissement partiellement submerge, modelisation numerique, mine a ciel ouvert, glissement rocheux actif., 1. IntroductionApproximately 90 km south of Quebec City, on the border between Black Lake sector to the north (part of Thetford Mines) and the municipality of Saint-Joseph-de-Coleraine to the south, [...]

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 economic link between the region and the Northeast USA. This paper is part of a proposed integrated remote sensing-numerical modelling methodology to analyze mining rock slope stability. This paper presents the Light Detection and Ranging (LiDAR) monitoring of this slope failure. The main focus is the investigation of that rock slide using both terrestrial (TLS) and airborne (ALS) LiDAR scanning. Since 2010, four ALS and 14 TLS were performed to characterize and monitor the slide. First, laser scanning was used to investigate the geometry of the slide. The failure zone was 1100 m by 250 m in size with a mobilized volume of 25 hm. Laser scanning was then used to investigate the rock slide's 3D displacement, thereby enabling a better understanding of the sliding kinematics. The results clearly demonstrate the ability of the proposed approach to monitor and quantify large-scale rock mass failure. The slope was monitored for a period of 5 years, and the total displacement was measured at every survey. The maximum cumulative total displacement reached was 145 m. This paper clearly shows the ability of LiDAR scanning to provide valuable quantitative information on large rock mass failures involving very large displacements. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]