Personne : Grenon, Martin
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Université Laval. Département de génie des mines, de la métallurgie et des matériaux
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Voici les éléments 1 - 10 sur 24
- PublicationAccès librePractical considerations in establishing the statistical reliability of geomechanical data(Chapman & Hall, 2019-07-17) Fillion, Marie-Hélène; Hadjigeorgiou, John; Grenon, Martin; Caumartin, RichardIn an underground mining operation, the design of safe excavations can be influenced by the quality and quantity of collected geomechanical data. Data collection is the first step in mine design, and a sufficient level of confidence in the input data should be reached depending on the project stage and the design requirements (e.g. temporary and non-entry vs. permanent and entry excavations). This paper compares two statistical analysis methods for quantifying the level of confidence in the intact rock properties obtained through a series of laboratory tests. The laboratory testing database of an underground hard rock mine was used to highlight the variations in the two methods. The impact of the two methods, from an engineering perspective, was illustrated with an example using the Kirsch analytical solution. This investigation demonstrated that the selection of the appropriate analysis method should be guided by the project requirements.
- PublicationAccès libreDeterministic 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(National Research Council Canada, 2018-01-18) Amoushahi, Sina; Grenon, Martin; Locat, Jacques; Turmel, DominiqueIn recent years, several large open-pit mines have started operating in the province of Quebec in Canada, and some of the largest planned pits are located close to public infrastructure. Historically, large open-pit mining has seldom been done in many mining regions, such as the Abitibi region, where underground mines are the norm. As an integral part of achieving social acceptability of open-pit mining, the stability of mining slopes must be carefully analyzed during the design process and the presence of public infrastructure near the slopes must be adequately considered. The province of Quebec does not have specific guidelines regarding such design considerations. This paper provides a short overview of the literature on some current practices regarding mining slope design close to public infrastructure. To demonstrate its applicability in the Quebec provincial context, the paper then investigates the stability of the west wall of the LAB Chrysotile open-pit mine in Thetford Mines (Quebec) near the new Road 112. Deterministic and probabilistic analyses were conducted using finite element shear strength reduction and limit equilibrium methods to investigate slope stability. The impact of pit infilling and rapid dewatering as well as long-term stability of the slope were investigated. The results of all analyses reveal that the current mining slopes at LAB Chrysotile are within acceptable design criteria limits.
- PublicationAccès libreStability analysis of vertical excavations in hard rock by integrating a fracture system into a PFC model(ScienceDirect, 2008-11-20) Esmaieli, Kamran; Hadjigeorgiou, John; Grenon, MartinThis paper presents an implementation of a comprehensive engineering approach to the analysis of the stability of vertical excavations in rock. This approach relies in the generation of discrete fracture systems to better capture the structural complexity of the rock mass. The resulting fracture system is consequently linked into a distinct element stress analysis. The particle flow code was selected as it potentially allows greater flexibility in representing a fracture system. In the first example a 3D fracture system was linked into a 2D PFC model. Although this has allowed for an improved quantification of stress structure interaction it necessitated important simplifications which may not be necessarily appropriate. These have been overcome by providing a complete integration of a 3D fracture system to a 3D PFC model. This will potentially lead into a design tool that adequately account for the stress structure interaction on the stability of vertical or near vertical excavations in hard rock.
- PublicationAccès libreOpen stope stability using 3D joint networks(Wien New York Springer, 2003-01-21) Hadjigeorgiou, John; Grenon, MartinThe most popular exploitation method used in Canadian hard rock mines is open stope mining. Geomechanical design of open stopes relies on a range of analytical, numerical, and empirical tools. This paper presents an engineering approach for the analysis and the design of reinforcement for open stopes in jointed rock. The proposed methodology, illustrated by three case studies, relies on developing 3D joint network models from field data. The 3D joint networks have been successfully linked to a 3D limit equilibrium software package. The models account for the finite length of joints as well as the influence of random joints. The integrated approach facilitates comparative analyses
- PublicationRestreintStatistical assessment of intact rock properties for two underground mining projects at Raglan Mine, Quebec, Canada(Taylor & Francis, 2020-04-30) Boudreau, Catherine; Grenon, Martin; Caumartin, Richard; Bruneau, Geneviève.The design of underground mining excavations relies on geotechnical characterization of intact rock through laboratory testing. As mining project development progresses through prefeasibility to production stages, the reliability of estimates of rock mechanics properties needs to increase. However, it is challenging to determine the number of tests needed to adequately estimate intact rock properties at different development stages. This paper looks at the early stages of an underground mining project in the Canadian Arctic where two field and laboratory testing campaigns were conducted to evaluate intact rock tensile and uniaxial compressive strength. Results were statistically compared to target confidence levels associated with different stages of a mining project. The study provides insights for planning future field and laboratory testing campaigns. The methodology also provides a quantitative means to assess whether additional laboratory testing is needed to improve tensile and uniaxial compressive strength estimates.
- PublicationRestreintÉtude des critères de fiabilité des bancs miniers : le cas de la fosse Tiriganiaq au Nunavut(Canadian Institute of Mining Metallurgy and Petroleum, 2012-01-18) Hadjigeorgiou, John; Matte, Pierre; Grenon, Martin; Kabuya Mukendi, Joseph; Brunet, Francis; LeBlanc, Daniel B.Bench stability in mines is an important element of pit design. There is no consensus on which criteria to use to evaluate the bench design reliability. When designing the pits, bench design reliability is analyzed according to one or two criteria. The objective of this paper is to analyze the bench design for the Tiriganiaq pit, part of the Meliadine mine project, with regards to the reliability criteria found in the literature and in practice. The paper presents the similarities and the differences between the results obtained according to the various criteria and it proposes a systematic multicriteria approach to evaluate pit bench design reliability using susceptibility maps.
- PublicationAccès libreAnalysis of a large rock slope failure on the east wall of the LAB chrysotile mine in Canada : LiDAR monitoring and displacement analysis(2017-04-01) Caudal, Philippe; Grenon, Martin; Locat, Jacques; Turmel, DominiqueA 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 hm3. 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.
- PublicationAccès libreSlope orientation assessment for open-pit mines, using GIS-based algorithms(Computer Oriented Geological Society, 2010-12-20) Laflamme, Amélie-Julie; Grenon, MartinStandard stability analysis in geomechanical rock slope engineering for open-pit mines relies on a simplified representation of slope geometry, which does not take full advantage of available topographical data in the early design stages of a mining project; consequently, this may lead to nonoptimal slope design. The primary objective of this paper is to present a methodology that allows for the rigorous determination of interramp and bench face slope orientations on a digital elevation model (DEM) of a designed open pit. Common GIS slope algorithms were tested to assess slope orientations on the DEM of the Meadowbank mining project's Portage pit. Planar regression algorithms based on principal component analysis provided the best results at both the interramp and the bench face levels. The optimal sampling window for interramp was 21×21 cells, while a 9×9-cell window was best at the bench level. Subsequent slope stability analysis relying on those assessed slope orientations would provide a more realistic geometry for potential slope instabilities in the design pit. The presented methodology is flexible, and can be adapted depending on a given mine's block sizes and pit geometry.
- PublicationAccès libreNumerical evaluation of grouting scenarios for reducing water inflows from major faults in underground excavations(Springer, 2019-01-19) Blessent, Daniela; Therrien, René; Grenon, Martin; Lemieux, Jean-Michel; Lajoie, Pierre-Luc; Domingue, Catherine; Molson, John W. H.Water inflows through fracture networks are a major economic and safety issue in underground mines. Although pre-grouting of pilot holes during mine development efficiently reduces water inflows into mine excavations, current design methods remain empirical. We used a finite-element numerical model to simulate groundwater inflow into a stope with the objective of finding the best configuration to increase pre-grouting efficiency for sealing faults while decreasing the associated costs. We designed simulations to test various grout injection scenarios for two different major fault locations around the stope, based on the site characteristics of the Éléonore mine (Québec, Canada). Sensitivity analyses show that, for a fault located above the stope, grouting the zone between the fault and the stope reduces inflow more than directly grouting the fault. Also, in the case of a fault intersecting a stope, the simulations suggest that the fault itself should be grouted as widely as possible, instead of sealing only the immediate surroundings of the stope.
- PublicationAccès libreRock slope stability analysis using fracture systems(2006-08-01) Hadjigeorgiou, John; Grenon, MartinThis paper presents a methodology whereby statistically representative fracture patterns can be used for an accurate representation of structural discontinuities in rock. This implies that field data can be used to generate characteristic fracture systems for a rock mass. It is then possible to introduce any range of slope geometry in the generated rock mass. The stability of such excavations can be evaluated using traditional limit equilibrium analysis. The advantage of this approach is that it can consider the influence of both large-scale (major) fractures whose relative location in the rock mass is well defined and minor fractures whose location and orientation is defined by probabilistic algorithms. This is demonstrated in this paper with reference to a rock slope susceptible to wedge-type failures.
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