Papers and Presentations
Piteau Associates has long recognized the value in advancing ideas, concepts and techniques through education, publishing research papers, and presenting and sharing ideas at symposiums and conferences.
2020
Risk-based slope monitoring framework. In Proceedings of Slope Stability 2020, May 12-14, Perth, Australia. (in-print)
Armstrong, J., Sharon, R., Williams, C., & Ross, B. (2020).
Slope design assessment, mining strategy, and development of geotechnical setback criteria for excavation of steep, natural escarpments in rugged mountainous Terrain. In Proceedings of Slope Stability 2020, May 12-14, Perth, Australia. (in-print)
Scholz, M.F., Gilmore, B.W., King, M.N.T., Hawley, P.M., & Aguirre-Freyre, C. (2020).
Geotechnical risk management for Victor Mine closure. In Proceedings of Slope Stability 2020, May 12-14, Perth, Australia. (in-print)
Desjardins, M., de Graaf, P., Beale, G., & Rougier, M. (2020).
Anglo American framework for strategic dewatering plans. In Proceedings of Slope Stability 2020, May 12-14, Perth, Australia. (in-print)
Cintolesi, C., Beale, G., Dowling, J., Kotze, J., Rowland, A., & Mansell, S. (2020).
Development of an integrated workflow for pit slope pore pressure reconciliation. In Proceedings of Slope Stability 2020, May 12-14, Perth, Australia. (in-print)
Dowling, J., Beale, G., Haas, P., Kaya, B., Tejada, L.C., Cramer, K., Johnson, J., Zea, R.E., & Palmer, C. (2020).
Development of a mine dewatering and pit slope depressurisation review process. In Proceedings of Slope Stability 2020, May 12-14, Perth, Australia. (in-print)
Reano, E., Beale, G., Dowling, J., & Tejada, L.C. (2020).
2019
Slope Steepening Investigations for the Valley Pit at the Teck Highland Valley Copper Mine using Presplit Blasting. Mining Engineering Magazine, 71(4), 16-30.
Rose, N., Veillette, M., & King, M. (2019)
Risk Assessments and Tailings Management. Presentation to US AID technology seminar on Best Management Practices for the Amazon, August 14, Lima, Peru & August 16 Bogota, Colombia.
Smith, M.E. (2019)
In Situ treatment for Heap Leach Closure. Presentation to US AID technology seminar on Best Management Practices for the Amazon, August 14, Lima, Peru & August 16 Bogota, Colombia.
Smith, M.E. (2019)
2018
Bioleaching and engineering properties of bioleach ore materials (overview). In Proceedings of EuroRock 2018, Int. Soc. for Rock Mechanics and Rock Engineering, May 22-26, St. Petersburg, Russia.
Shidlovskaya, A.V., Timchenko, A.A., & Smith, M.E. (2018).
Importance of characterization and representation of fault damage zones in slope stability models, In Proceedings of Slope Stability 2018 and XIV International Congress on Energy and Mineral Resources (pp. 44-49), April 10-13, Seville, Spain.
Severin, J. (2018)
Quantifying Transitional Rock Mass Disturbance in Open Pit Slopes Related to Mining Excavation. In Proceedings of Slope Stability 2018 and XIV International Congress on Energy and Mineral Resources, April 10-13, Seville, Spain.
Rose, N.D., Scholz, M., Burden, J., King, M., Maggs, C., & Havaej, M. (2018).
Managing the Interaction between the Unstable West Highwall and the 2B Underground at the Barrick Golden Sunlight Mine, Montana, USA. In Proceedings of Slope Stability 2018 and XIV International Congress on Energy and Mineral Resources, April 10-13, Seville, Spain.
Turner, R.M., Rose, N.D., Langston, R.B., & Cabello, J. (2018).
Alternative Methodology for Interpreting Discontinuity Direct Shear Data
King, M.N.T., Ballantyne, S.M., & Elmo, D. (2016)
Abstract
Direct shear testing is a standard laboratory technique used to determine the shear strength properties of discontinuities. The results are useful for characterizing rock mass strengths and are a key input in a wide range of rock slope stability analysis methods. Several approaches to interpreting direct shear data as described in rock mechanics textbooks and industry standards are discussed. An alternative interpretation approach, the line-fitting method, is then presented, supported by extensive rock discontinuity shear strength data from direct shear testing from projects throughout North and South America. Reliable peak strength properties are often difficult to obtain from small-scale direct shear testing of rock discontinuities. A more reliable approach is to interpret lower and upper bound values of shear strength based on the testing data. The proposed line-fitting method enables the characterization of discontinuity shear strengths by defining the range of expected values from testing results where peak behaviour is not observed.
2016
Guidelines for Waste Dump and Stockpile Design. In Proceedings of the CIM Annual Convention, May 1-4, Vancouver, B.C.
Hawley, P.M., & Cunning, J. (2016)
Cross-over of directional well placement technology enhances mine dewatering.
Dowling, J., & Rhys-Evans, G. (2016).
Pump up performance, a review of high efficiency pumping technology for mine dewatering. Mining Magazine, March 15.
Dowling, J., & Lang, K. (2016). Mining Magazine, April 15.
Risk assessment in the mining industry – A critique. In Proceedings of Risk and Resilience Mining Solutions, November 14-16, Vancouver, Canada.
Smith, M.E., & Sinha, K. P. (2016).
Abstract
The impacts and consequences of failure can be enormous and devastating, as demonstrated by many failures of the past and, more recently, by Mount Polley (Canada) and the Buenavista del Cobre (Mexico) tailings storage facility failures. As such, performing risk assessments of mining projects is not only essential, but such assessments should be continually revised and updated since the conditions and the components of risk change through various stages of the project – from construction through operation to closure and long-term care. Much has been written about the overall methodology of risk assessment and risk management. Risk identification, analysis, evaluation, and control elements of the process have been amply described and discussed. Standards and procedural guidelines have also been set forth and are routinely used. In the authors’ experience, however, the risk review process often becomes simply a procedural obligation and is reduced to little more than a check-the-boxes exercise limited to a few hours of meeting of the leads of various areas and populating a template. The goal of this effort is generally to produce a list of risks that are either below the required threshold or which can be easily mitigated, and thus brought below the threshold. On the other hand, the thresholds set by one or the other system commonly relied upon – for example, the risk rating systems developed by several Tier 1 miners, may themselves be open to discussion. This paper provides a reflection on the risk assessment or review process as often conducted in the mining industry, and points to a few pitfalls and deficiencies through some specific examples. Examples of risk assessment processes for specific projects as well as an overall business venture or operation are used to illustrate the point.
Risk management and decision making as related to mill tailings disposal. In Proceedings of Risk and Resilience Mining Solutions, November 14-16, Vancouver, Canada.
Crystal, C.A., & Smith, M.E. (2016).
Abstract
This paper explores risk management and decision making as related to mill tailings disposal from the perspective of three broad categorizations of risk - preventable, strategic and external risks. Risks from any of the three categories can be fatal to a company's strategy, social license to operate and even to its survival; but while preventable risks, can be monitored and controlled through rules, values, standards of practice, standard compliance tools and best management practices; successfully managing strategic risks is a key driver in capturing potential financial gains from any endeavor (across a broad range of industries) and requires a fundamentally different approach. External risks are those that are outside the control of a firm (commodity prices, global politics and natural events such as floods and earthquakes) that can only be managed by reducing the impact of the consequences, not the likelihood of the event, itself. The paper provides key examples from both the mining (and other) industry risk management approaches to highlight how companies can go about identifying and anchor risks; and tailoring their risk management and decision making. The paper explores inherent biases in common risk ranking approaches that drive us to filter out the extremes. The paper highlights common pitfalls such as firms inadvertently incubating risk as they learn to tolerate apparently minor failures and defects; as well as the risk of not identifying the potential of seemingly unrelated events or decisions, that did, if taken in totality, lead to catastrophic failure but which, if only one of a number of smaller preventable failures had been addressed may not have occurred; to the "human factor". The paper explores strategic risk management and risk decision making in the context of the inclusion of risk event costs in trade-off studies and total project valuations.
Keynote address: How our Understanding of Water and Slope Stability has Improved since 2009. In Proceedings of Slope Stability 2018 and XIV International Congress on Energy and Mineral Resources, April 10-13, Seville, Spain.
Beale, G. (2018).
High Resolution Monitoring Underpins Implementation of Cost Effective Groundwater Control Measures During Construction of New Access Decline, Cabanasas Mine, Suria, Catalunya, Spain. In Proceedings of Slope Stability 2018 and XIV International Congress on Energy and Mineral Resources, April 10-13, Seville, Spain.
McKittrick, R. Saavedra, C., & Asbert, J. (2018).
Groundwater and surface water monitoring in support of municipal and commercial groundwater extraction with case studies
Tiplady, D., & Burgert, A.
Abstract
This presentation will highlight the benefits of implementing a comprehensive groundwater and surface water monitoring program as a management tool in support of long-term groundwater extraction. It will show how monitoring of key hydrologic indicators such as water levels, water temperature, and water chemistry can provide useful information on aquifer and well performance, sources of recharge, surface water - groundwater interaction, and other factors that can lead to improved understanding, identification of risk, and effects resulting from well operation. Amongst other things, monitoring information can be used in support of groundwater licensing under the Water Sustainability Act, dispute resolution, and determining safe aquifer yield. Examples from monitoring programs for municipal water supply systems at Whistler and Abbotsford, and a commercial water bottling operation in Hope, will be presented.
Dynamic environmental monitoring networks: Saving on lab costs versus keeping your regulator happy
Allard, R., & Stewart, M.L.
Abstract
With increasing pressure on annual budgets, local government is always looking for opportunities to optimize operational costs. This presentation develops an argument in support of a reduction of environmental sampling costs associated with compliance monitoring for landfills and wastewater effluent disposal facilities. The argument is based on simple graphical and statistical methods to support the optimization of an existing sampling network. Significant cost-savings without increased risk are attainable based on a robust hydrogeological and statistical understanding combined with adaptive management.
Groundwater Monitoring in the Lornex Pit – Highland Valley Copper. In Proceedings of the CIM Annual Convention, May 1-4, Vancouver, B.C.
Holmes, A.T., Veillette, M., Shwydiuk, L., & Stewart, M.L. (2016).
Adapting Oil and Gas Drilling Techniques for the Mining Industry with Dewatering Well Placement Technology. In Proceedings of the New Technology and Innovation in the Minerals Industry Colloquium, Southern African Institute of Mining and Metallurgy (SAIMM) (pp. 63-74), June 9-10, Johannesburg, RSA.
Rowland, A., Bester, M., Boland, M., Cintolesi, C., & Dowling, J. (2016).
Abstract
Although increasing R&D spent to develop original technologies will benefit the mining industry, adaptation of appropriate existing technologies from other industries can be a more cost-effective alternative. Schlumberger Water Services, now WSP|Parsons Brinckerhoff, has undertaken a 6-year programme assessing the adaptation of oil and gas (O&G) drilling and geophysical characterization techniques to a range of mining applications, including dewatering. Conventional dewatering systems for open pit mines generally use vertical boreholes that target hydraulically productive zones within an orebody. The drilling and completion of vertical dewatering boreholes can be complicated by mine planning constraints, where optimum hydrogeological targets are not accessible from the available drilling locations. As these boreholes are often located within the operating open pit, they can interfere with the mining operation and the ability to carry out significant dewatering ahead of mining is limited. Dewatering Well Placement Technology (DWPt) is WSPlParsons Brinckerhoffs next-generation mine dewatering solution aimed at addressing the limitations of conventional dewatering systems through placement of permanent, high-performance dewatering wells in optimum orientations beneath an open pit using large-diameter directional drilling technology commonly used in O&G. Ideally, well collars are located outside of the mine operating areas, resulting in improved compatibility between the dewatering system and mine plan. Recently drilled and constructed pilot directional dewatering wells in hard rock mining environment in the USA and Mexico have demonstrated that DWPt offers significant benefits for groundwater inflow control and value to mining operations compared to conventional open pit mining dewatering practices.
Cross-over of directional well placement technology enhances mine dewatering. Mining Magazine, March 15.
Dowling, J., & Rhys-Evans, G. (2016).
Pump up performance, a review of high efficiency pumping technology for mine dewatering. Mining Magazine, April 15.
Dowling, J., & Lang, K. (2016).
2015
Building a Rock Mass Model for a Large Open Pit. In Proceedings of the 49th US Rock Mechanics/Geomechanics Symposium (ARMA2015), June 28-July 1, San Francisco, CA.
Capdeville-Pérez, F. (2015)
Abstract
This article proposes a methodology for building a rock mass model for the Toquepala Mine. This model will be used as an input for analyses to evaluate the stability of the current and future open pit slopes. The rock mass modeling process can be divided into two phases: a database building phase which involves gap analysis and data collection, compilation and validation; and an analysis phase that involves data assessment and the definition of rock mass units (RMUs). This article briefly describes each of these phases and how they have been applied at the Toquepala Mine, with emphasis on the data assessment and definition of the different RMUs.
Characterisation of groundwater and effective measures for management in mine operations. Presentation given at the 4th Technical Mining Seminar ‘Mining and Water’, May 13, Manresa, Catalunya, Spain.
McKittrick, R. (2015).
Development of an early-warning time-of-failure analysis methodology for open-pit mine slopes utilizing ground-based slope stability radar monitoring data. Canadian Geotechnical Journal, 52(4), 515-529.
Dick, G.J., Eberhardt, E., Cabrejo-Liévano, A.G., Stead, D., & Rose, N.D. (2015)
Abstract
The recent introduction of ground-based slope stability radar in open-pit mines to complement conventional geodetic monitoring programs provides near real-time deformation measurements over a broad coverage area; this allows geotechnical engineers to observe the spatial distribution of pit wall movements and their progression over time. This paper presents a newly proposed early warning time-of-failure (TOF) analysis procedure for use in real-time with ground-based radar measurements designed to be integrated in an open-pit mine’s trigger action response plan (TARP). The inverse-velocity and slope gradient (SLO) TOF analysis methods are applied to radar displacement measurements using a new systematic multi-pixel selection technique termed the “percent deformation method.” The utilization of the percent deformation method in the proposed real-time TOF analysis methodology gives more-reliable results than current practice by providing recommendations for pixel selections, data filtering, where and how to undertake TOF analyses, and presenting TOF results in real time. The addition of a more rigorous, methodical treatment of radar monitoring data when faced with critical slope instability will reduce uncertainty and increase confidence in any trigger action response decisions, helping to ensure a safer work environment.
Characterisation of groundwater and effective measures for management in mine operations. Presentation given at the 4th Technical Mining Seminar ‘Mining and Water’, May 13, Manresa, Catalunya, Spain.
McKittrick, R. (2015).
Characterisation of groundwater and effective measures for management in mine operations. Presentation given at the 4th Technical Mining Seminar ‘Mining and Water’, May 13, Manresa, Catalunya, Spain.
McKittrick, R. (2015).
2014
Control de aguas subterráneas, construcción de rampa Mina Cabanasses, Suria, Espana. Presentation given at the IGME / CAS conference: Jornadas Agua Subterranea y Mineria, May 28-29, Madrid, Spain.
McKittrick, R. (2014).
Integration of IBIS monitoring system with hydrogeology programme. Presentation given at IBIS (Georadar and slope monitoring) workshop and conference, May 8, Pisa, Italy.
McKittrick, R. (2014).
Modelación hidrogeológica 3D aplicada a la minería. Presentation at IGME / CAS conference: Jornadas Agua Subterranea y Mineria, May 28-29, Madrid, Spain.
Piñana, E. (2014).
Guidelines for Evaluating Water in Pit Slope Stability. Melbourne, Australia: CSIRO Publishing, 680p.
Beale, G., & Read, J. (Eds.).
Site Characterisation. In G. Beale & J. Read (Eds.), Guidelines for Evaluating Water in Pit Slope Stability. Melbourne, Australia: CRC Press.
Beale, G., & Read, J. (Eds.).
Numerical Model. In G. Beale & J. Read (Eds.), Guidelines for Evaluating Water in Pit Slope Stability. Melbourne, Australia: CRC Press.
Lorig, L., Dowling, J., Beale, G., & Royle, M. (2014).
A combined remote sensing–numerical modelling approach to the forensic investigation of catastrophic rock slope failures. In Proceedings of the 65thCanadian Geotechnical Conference (GeoRegina 2014), September 28-October 1, Regina, SK.
Wolter, A., Stead, D., Clague, J., Havaej, M., & Vivas, J. (2014)
Abstract
We combine an analysis of aerial imagery, digital terrestrial photogrammetry, and numerical modelling to investigate the 1959 Madison Canyon Slide and the 1963 Vajont Slide. Aerial imagery and LiDAR served as base maps for engineering geomorphology mapping and allowed us to document landslide blocks and a relative chronology of events for each mass movement. Photogrammetry provided access to remote areas of the landslides and allowed us to map discontinuity sets, analyse deposit morphology at Madison Canyon, and create a preliminary morphology classification of the Vajont failure scar. The kinematics, dynamics, and initiation were investigated using a suite of numerical modelling codes.
2013
Early detection of impending slope failure in open pit mines using spatial and temporal analysis of real aperture radar measurements. In P.M. Dight (Ed.), Slope Stability 2013, Proceedings of the 2013 International Symposium on Slope stability in Open Pit Mining and Civil Engineering 25-27 September (pp. 949-962), Brisbane, Australia: Australian Centre for Geomechanics.
Dick, G.J., Eberhardt, E., Stead, D., & Rose, N.D. (2013)
Abstract
Slope monitoring in open pit mines is an essential component of day-to-day operations and plays a key role in assisting geotechnical engineers and mine operators in maintaining mine safety and production schedules. Pit slope monitoring techniques have advanced significantly within the past decade, most notably in ground-based radar technology. Ground-based radar allows real-time monitoring of slope deformation across a broad coverage area, alerting mine staff to wall movements exceeding established thresholds. Line-of-sight measurements derived from the radar can be presented as 3D point clouds for the scan area, allowing mine staff to view the distribution of slope movements across the pit wall with each progressive scan.
This paper presents a new methodology for spatial and temporal analysis of deformation point clouds captured by ground-based radar. The methodology builds on two existing early warning methods, the Fukuzono inverse-velocity method and the SLOpe gradient (SLO= method, which are based on the analysis of point measurement data derived from traditional geodetic prism monitoring. However, similar methodologies that fully utilize the spatial and temporal characteristics of ground-based radar data are yet to be developed. Radar data from historical slope failures captured by GroundProbe Slope Stabiltiy Radar (SSR) at a number of hard rock mines was utilized in the development of the new spatial and temporal analysis methodology. A slope failure that occurred at an open pit copper mine is presented throughout as a case example. The spatial analysis component of the methodology uses a benchmark point (or pixel), based on an alarm threshold specific to each failure case, and averaged deformation increments based on a percentage of the deformation measured by the benchmark pixel at the time of alarm. The temporal analysis component of the methodology examines deformation and velocity trends for all spatial analysis cases. The results of the spatial and temporal analysis were then used to evaluate the inverse-velocity and SLO time of failure prediction methods. Overall, the proposed methodology will improve, and provide a more systematic means of interpreting spatial and temporal ground-based radar data, aiding geotechnical engineers in managing slope movement alarms and alarm responses to provide a safer working environment for mine employees.
Site Characterisation. In G. Beale & J. Read (Eds.), Guidelines for Evaluating Water in Pit Slope Stability (pp. 65-152). Melbourne, Australia: CSIRO Publishing.
Doubek, G., Creighton, A., Dowling, J., Price, M., & Hawley, P.M. (2013)
Water Control as a Means to Improve Slope Stability. Mining Magazine.
Beale, G., Dowling, J., & Reidel, J. (2013).
An Integrated Model for Dewatering at the Bagdad Mine. In A. Brown, L. Figueroa, & C. Wolkersdorfer (Eds) Proceedings of Annual International Mine Water Association Conference - Reliable Mine Water Technology (pp. 125-132), 1, Denver, CO.
Dowling, J., Zimmerlund, B., Kennealy, J., & van den Berg, E. (2013).
Abstract
The ore deposit hydrogeology of large open pit porphyry copper mines in the southwestern U.S. typically involves large spatial variability in rock hydraulics. An integrated conceptual hydrogeologic model and validated predictive groundwater model are key to assessing dewatering and pit slope depressurization. In the case of the Bagdad mine, in Arizona, a 3D empirical model of the hydrogeology was developed using Petrel software. Three-dimensional hydrogeologic properties were exported to the MODFLOW-SURFACT groundwater modeling code providing a tool to target geologic zones for dewatering and pit slope depressurization. The resulting simulation accurately represents pit conditions and enhances mine planning.
Designing a Large Scale Pit Slope Depressurization System at Bingham Canyon, A. Brown, L. Figueroa, & C. Wolkersdorfer (Eds) Proceedings of Annual International Mine Water Association Conference - Reliable Mine Water Technology (pp. 119-125), 1, Denver, CO.
Dowling, J., Beale, G., & Bloom, J. (2013).
Water Control as a Means to Improve Slope Stability. Mining Magazine.
Beale, G., Dowling, J., & Reidel, J. (2013).
2012
Evolution of a numerical pit slope dewatering simulation through refinement of a 3D geology model. Paper presented to the 2012 International Association of Hydrogeologists (IAH) Congress, September 16-21, Niagara Falls, ON.
Stewart, M.L., & Holmes, A.T. (2012)
Abstract
The northeast slope (Big Bear) of the Valley Pit at the Teck Highland Valley Copper mine in BC Canada has historically experienced a significant amount of deformation along weak, pre-sheared glaciolacustrine clay horizons. Short-term mitigation of slope failure risk during buttress construction and long term performance of the Big Bear slope relies on controlling piezometric levels within the lacustrine clay units by operating a multifaceted, dedicated dewatering system designed with the assistance of 3D numerical simulations in FEFLOW. Active dewatering wells and one-meter diameter passive vertical drains were installed as a part of aggressive dewatering measures undertaken from 2009 to present.
Early simulations of the groundwater flow regime in the Big Bear slope relied on geology models constructed from limited early drilling and a priori conceptual understanding of the 3D stratigraphy of the Big Bear Slope. As the complexity of the stratigraphic interfaces modelled in the Big Bear slope increased with knowledge gained from drilling in 2009 and 2010, the hydraulic conductivity distribution assigned to the numerical model was greatly simplified while still achieving a higher degree of accuracy and precision in the calibration of the numerical simulations. The lessons learned during this project remind us that making simplistic assumptions in one facet of a numerical model (e.g. planar stratigraphic interfaces) can force us to make un-necessarily complex interpretations in others (e.g. hydraulic conductivity distributions). Ignoring the importance of 3D geometry incorporated in a numerical model can undermine efforts to construct an accurate hydrogeological simulation and more importantly can impede critical decision-making in mitigating slope failure.
Samatosum – A Review of Two Early Acid Drainage Prevention Approaches. In W.A. Price, C.Hogan & G. Tremblay (Eds.), Proceedings of the 9th International Conference on Acid Rock Drainage (pp. 572-584). Ottawa, ON: Curran Associates Inc.
Holmes, A.T., Hamblin, B., Hogarth, J., Craig, F., & Anderson, T. (2012)
Abstract
Two acid drainage (AD) mitigation measures incorporated into the design of the Samatosum Mine Project have displayed diverse outcomes: the water covered tailings impoundment was very successful; the layered waste rock dump was not successful. The effectiveness of the AD mitigation measures has been monitored since they were implemented. Discharge from the waste dump became acid briefly during the 1995 freshet. Since 1995, the primary seep from the waste dump has become acid during every freshet, and a small seep is acid almost all of the time. A water collection and treatment system was commissioned before the 1997 freshet, and has been in operation since that time. An on-site sludge management program has been implemented to manage the residuals from the treatment process. Potentially acid generating (PAG) tailings were deposited in an impoundment designed to maintain a water cover over the tailings. There have been no indications of AD from the tailings facility to date. Water management and treatment facilities, and their post closure operation, are described in this paper. Monitoring results are also presented and discussed.
2011
Keynote Paper: Investigating the Effects of Mining Induced Strain in Open Pit Slopes. In Proceedings of the Slope Stability 2011 Conference, International Symposium on Rock Slope Stability in Open Pit Mining and Civil Engineering, September 18-21, Vancouver, B.C. Rose, N.D. (2011)
Abstract
Modern open pit slope design is increasingly requiring meaningful forecasts of slope deformation behaviour during mining, in addition to traditional design approaches used to satisfy slope stability. As open pit mines become deeper and stability mechanisms become more complex, optimizing ore extraction while maintaining stability may require detailed design investigations to maximize slope angle while maintaining acceptable levels of risk. In situations where ultimate pit mining encroaches on surface or underground infrastructure, design acceptability criteria require incorporation of deformation tolerances in addition to traditional factor of safety or probability of failure criteria. This requires numerical modeling techniques, such as distinct element modeling, that incorporate a detailed representation of the engineering geology and groundwater conditions and the mining excavation sequence. Validation of model input parameters is established through careful calibration of model displacements with actual slope monitoring data during back analysis. Slope deformation forecasts can then be used to define acceptable movement magnitude, rate and strain threshold criteria. This paper describes the use of detailed distinct element modeling to investigate the influence of strain-induced degradation (disturbance) of the rock mass that occurs in slopes as a result of stress relief and relaxation during mining. Recognizing the potential adverse effects of mining-induced strain is important in defining appropriate design strength parameters, and hence, successful geotechnical slope designs. As current analytical methods may be limited in addressing the time-dependent strength behaviour of geological materials, deformation forecasts must be continually evaluated with slope displacement monitoring to confirm the validity of analytical forecasts. To safeguard against destabilizing slope conditions, if they were to occur, empirical failure time prediction and runout assessment methods can be used to define slope monitoring thresholds and hazard zones.
Investigation, Design and development of the Valley Pit Big Bear pushback at the Teck Highland Valley Copper Mine. In Proceedings of the Slope Stability 2011 Conference, International Symposium on Rock Slope Stability in Open Pit Mining and Civil Engineering, September 18-21, Vancouver, B.C.
Fortin, S., Rose, N.D., & Holmes, A.T. (2011)
Abstract
The expansion plan for the Valley pit at the Teck Highland Valley Copper (THVC) mine, BC, Canada involves a pushback on the east wall through a 225m thick sequence of glacial overburden sediments (Big Bear). This slope has historically experienced a significant amount of deformation along weak, pre-sheared glaciolacustrine clay horizons. This paper summarizes the integrated approach undertaken by THVC to rally engineering design, mine planning and operational practice to execute controlled excavation and placement of a seven million tonne waste rock stabilization buttress using slot-cut mining methods. The long-term performance of the Big Bear slope in-turn relies on controlling piezometric levels within the lacustrine clay units by operating a dedicated depressurization system. A comprehensive field investigation program was carried out to define the engineering geology and hydrogeological conditions in the slope. A hydrogeological model was developed to assist the design of a depressurization system comprised of 77 active wells and 27 one-meter diameter passive vertical drains. Detailed design assessments were conducted to define a stable slope configuration and predict slope deformation using a combination of limit equilibrium and numerical modelling methods. At the early stage of this project, Teck Resources performed a risk assessment to identify and manage the risks associated with the Big Bear mining phase. A trigger action response plan was created and mine planning and scheduling decisions were made through continuous assessment of risk to personnel, equipment and ore reserves. This resulted in the optimization of buttress dimensions, the slope depressurization system design and completion of a final mining plan in late 2010. The Big Bear mining phase is forecasted to be completed in mid 2011.
A review of Key Factors Influencing Mine Dewatering and Pit Slope Depressurization. In Proceedings of the Slope Stability 2011 Conference, International Symposium on Rock Slope Stability in Open Pit Mining and Civil Engineering, September 18-21, Vancouver, B.C.
Dowling, J., Reidel, J., & Beale, G. (2011).
Abstract
Control and management of groundwater is a fundamental component of most successful large open pit mining operations. The key factors that affect groundwater control can vary significantly according to site-specific hydrogeologic conditions, the size of the mining operation, and the mine plan. This paper reviews typical hydrogeological settings for mine operations, criteria for planning, investigating and implementing an integrated dewatering and slope depressurization program.
2010
Dewatering of the Peñasquito Pit Lake. In Proceedings of the 2nd International Congress on Water Management in the Mining Industry (pp. 297-309), June 9-11, Santiago, Chile.
Dowling, J., Lang, K., & Munson, T. (2010).
Estudio de Inundabilidad Correspondiente al Plan General de la Ciudad de Tarragona, October, Ayuntamiento de Tarragona. Piñana, E. (2010). Dewatering of the Peñasquito Pit Lake. In Proceedings of the 2nd International Congress on Water Management in the Mining Industry (pp. 297-309), June 9-11, Santiago, Chile.
Dowling, J., Lang, K., & Munson, T. (2010).
2009
A practical Rockfall Hazard Identification system for open pit mining slopes. In Proceedings of the Slope Stability 2009 Conference, November 9-11, Santiago, Chile.
Gilmore, B.W., Hawley, P.M., & Pottie, J. (2009)
Abstract
Rockfalls are a major hazard in an open pit mining environment. A comprehensive rockfall hazard identification and mapping system was recently developed and is being systematically implemented on a trial basis at the Antamina Mine in Perú. The system sequentially evaluates a number of parameters to arrive at one of five qualitative hazard levels (from Very Low to Very High). The parameters considered to be most important for identifying rockfall hazards in the Antamina open pit are: 1) the slope height above the area of interest; 2) the presence of mining activities above the slope; 3) the condition of benches and bench faces and quality of scaling; and, 4) the presence and effectiveness of rockfall impact berms. The rockfall hazard levels identified throughout the pit using these criteria are displayed on a current mine status plan. This hazard level status plan is posted in key locations to convey the information to mine personnel, and is used to facilitate discussions and directives during safety, operations, and planning meetings.
Analysis of complex deformation behaviour in large open pit mine slopes using the Universal Distinct Element code (UDEC). In Proceedings of the Slope Stability 2009 Conference, November 9-11, Santiago, Chile.
Rose, N.D., & Scholz, M.F. (2009)
Abstract
The design of large open pit mine slopes using conventional limit equilibrium or continuum-based numerical analysis approaches can often be insufficient in addressing the complex interaction of geologic structure, insitu and induced stresses, groundwater and rock mass strength conditions. This interaction can be particularly important in environments where strain softening effects from mining-induced stress relief may lead to progressive slope failure or where design tolerances to slope deformations are low, such as in areas of permanent mine facilities, critical haulroads or crown pillars. This document provides a methodology and four case examples of distinct element modeling in large open pit mine slopes using UDEC in addition to conventional design approaches. UDEC modeling incorporated detailed back analysis of complex slope deformations by evaluating strain-softening behaviour with bench-by-bench mining to provide multi-point calibration of slope monitoring data at each excavation stage. Where a high level of input data quality was available, detailed calibration has provided remarkably accurate predictions of actual slope deformation behavior that was reconciled during and following mining. These forecasts allowed slope monitoring threshold displacement magnitudes and rates to be developed, providing a basis for ongoing evaluation of slope stability and development of operational response criteria. In two case examples, slope steepening was implemented in the latter stages of mining based on predictions of manageable slope conditions.
Assessing slope performance. In Proceedings of the Slope Stability 2009 Conference, November 9-11, Santiago, Chile.
Hawley, P.M. (2009)
Abstract
Chapter 12 of the Guidelines for Open Pit Slope Design (CSIRO (1)) provides a comprehensive review of the principles and methodologies for assessing slope performance, reviews slope monitoring techniques, provides guidelines for establishing slope monitoring programs, and introduces the concept of ground control management plans. This paper presents a summary of the key concepts and techniques for assessing slope performance at the bench, inter-ramp and overall slope scales.
Mine operation and management of progressive slope deformation on the south wall of the Barrick Goldstrike Betze-Post Open Pit. In Proceedings of the Slope Stability 2009 Conference, November 9-11, Santiago, Chile.
Armstrong, J., & Rose, N.D. (2009)
Abstract
Slopes experiencing significant deformation and rock quality deterioration may present rockfall and debris runout hazards to personnel and equipment. This paper discusses the engineering, planning, and operational steps taken at the Barrick Goldstrike Mine, Nevada, USA to understand and mitigate the risks associated with mining beneath a 450m high pit wall undergoing progressive slope deformation.
Through a process of geotechnical investigation to update and verify geological, structural, and hydrogeological conditions, detailed design assessments were carried out to provide comprehensive predictions of slope performance using limit equilibrium and advanced numerical modeling codes. Monitoring threshold and operational response criteria were developed based on modeling predictions of surface displacements, displacement rates, and debris runout potential. Assessments of hazard exposure and risks to personnel, equipment, and ore reserves were carried out to assist with mine planning and scheduling decisions. Contingency plans were implemented to accelerate the mining rate on the south wall, thereby reducing exposure during spring months that may be subject to increased pore pressure development from snow melt. The combined results of these assessments allowed slope steepening to be carried out in the latter stages of mining to maximize ore extraction while managing operational hazards at acceptable levels of risk.
Performance Assessment and Monitoring. In J. Read & P. Stacey (Eds.), Guidelines for Open Pit Slope Design (pp. 327-380). Melbourne, Australia: CSIRO Publishing.
Hawley, P.M., Marisett, S., Beale, G., & Stacey, P. (2009)
Groundwater remediation programme – La Coipa Mine, Minera Mantos de Oro, III región, Northern Chile. Paper and presentation for Enviromine Conference 2009, September 30-October 2, Santiago, Chile.
Villalobos, E., & McKittrick, R. (2009).
Field Data Collection. In J. Read & P. Stacey (Eds.), Guidelines for Open Pit Slope Design. Melbourne, Australia: CRC Press.
Read, J., Jakubec, J., & Beale, G. (2009).
Hydrogeological Model. In J. Read & P. Stacey (Eds.), Guidelines for Open Pit Slope Design. Melbourne, Australia: CRC Press.
Beale, G. (2009).
2008
2008 Rapid Filling Process and Evolution of the Kori Kollo Mine Pit Lake. In Proceedings of 2008 SME Annual Meeting and Exhibit, February 24-27, Salt Lake City, Utah.
Reidel, J. (2008).
2007
Forecasting potential rock slope failure in open pit mines using the inverse-velocity method. International Journal of Rock Mechanics and Mining Sciences, 44(2), 308-320.
Rose, N.D., & Hungr, O. (2007)
Abstract
Forecasting potential slope failure in open pit mines is necessary to maintain safety and mine productivity. Laboratory testing of rain induced landslides in Japan 20 years ago led to an inverse-velocity approach for estimating the time of slope failure. This approach appears to have been largely overlooked in mining, but has now been successfully applied, aiding in the prediction of three large slope failures ranging in size from 1 to 18 million cubic metres and control of another large instability. The predictions were forecasted five days to three months in advance of failure. This paper provides an overview of the development of inverse-velocity as a tool for failure prediction and a detailed discussion of the advantages and limitations of the technique, illustrated by examples from the literature. Four original case examples of successful application of this approach are then described. Forecasting rock slope failure is a complex problem, involving observations, analysis and experienced judgment. In many cases, the inverse-velocity method is a simple, but powerful tool aiding this process.
Forecasting potential slope failure in open pit mines using the inverse-velocity method – case examples. In E. Eberhardt, D. Stead & T. Morrison (Eds.), Rock Mechanics: Meeting Society’s Challenges and Demands, Volume 2 – Case Histories (pp. 1255-1262). Vancouver, B.C.: Taylor & Francis.
Rose, N.D., & Hungr, O. (2007)
Abstract
Forecasting potential rock slope failure in open pit mines is necessary to maintain safety and mine productivity. Laboratory testing of rain induced landslides in Japan over 20 years ago led to an inverse-velocity approach for estimating the time of a slope failure. This approach appears to have been largely overlooked in mining, but has been successfully applied in aiding the prediction of three large slope failures and control of another large instability. The predictions were forecasted five days to three months in advance of failure. This paper provides an overview of the development of inverse-velocity as a tool for rock slope failure prediction and presents four case examples of the successful application of this approach. Forecasting rock slope failure is a complex problem, involving observations, analysis and experienced judgement. In many cases, the inverse-velocity method is a simple, but powerful tool aiding this process.
Strategies and Technologies for Early Mine Closure Planning. In A. Fourie, M. Tibbett, & J. Wiertz (Eds) Proceedings of Mine Closure 2007, October 16-19, Santiago, Chile.
McKittrick, R.P., Lang, K.J., Rowe, J.W., Harrington, J.R., & Johnson, B.C. (2007).
Development and Protection of Water Resources in Northern Chile. Presentation at CRU World Copper Conference, March 28, Santiago, Chile.
McKittrick, R. (2007).
Working against the flow. Mining Journal, June, 35-38.
Dowling, J., & Ashinhurst, T. (2007).
Relieving the pressure. Mining Journal, June, 32-34.
Dowling, J., & Ashinhurst, T. (2007).
Seasonal variability in the concentration and flux of organic matter and inorganic nitrogen in a semiarid catchment, San Pedro River, Arizona. Journal of Geophysical Research, 112 (G3), July 4.
Brooks, P.D., Haas, P.A., & Huth, A.K. (2007)
Abstract
Streams and rivers in semiarid environments are characterized by highly variable discharge associated with seasonal precipitation patterns. To characterize how this variability in discharge affects the concentration and flux of organic matter and inorganic nitrogen, we measured discharge and collected water samples in the San Pedro River in southeastern Arizona from April 2001 through September 2002. Mean daily discharge during the study ranged from 2.5 × 103 m3 day−1 to 9.4 × 105 m3 day−1, with low discharge in late June followed shortly thereafter by the highest discharge in July or early August after the onset of monsoon storms. Dissolved Organic Matter (DOM) dominated carbon and nitrogen flux during the non-monsoon season, while Particulate Organic Matter (POM) dominated flux during the monsoon. The concentrations of Dissolved Organic Carbon and Nitrogen (DOC, DON), and NO3-N typically increased 2- to 10-fold, while POM increased by 2 to 3 orders of magnitude during the monsoon season. Concurrent increases in concentration and discharge resulted in 96% of the annual organic carbon (DOC + POC) and 97% annual nitrogen (DIN + DON + PON) flux occurring during the monsoon season with the majority of both organic carbon (92%) and total nitrogen (83%) being transported as particulates. These data indicate that POM transported during the monsoon season may be a major source of carbon and nitrogen to the stream ecosystem, potentially fueling heterotrophic activity in sediments and the hyporheic zone after the monsoon season and associated floods have ended.
Influence of shifting flow paths on nitrogen concentrations during monsoon floods, San Pedro River, Arizona. Journal of Geophysical Research, 112(G3) August 18.
Meixner, T., Huth, A.K., Brooks, P.D., Conklin, M.H., Grimm, N.B., Bales, R.C., Haas, P.A., & Petti, J. R. (2007).
Abstract
Hydrologic flow paths control transport, and therefore are a major constraint on the cycling and availability of nutrients within stream ecosystems. This control is particularly evident in semiarid streams, where hydrologic connectivity between stream, riparian, and upland systems increases greatly during storms in the rainy season. We measured chloride concentrations in base flow, precipitation, soil water, and stream water to quantify the hydrologic connectivity and solute flux between soil water, groundwater, and the stream channel during six summer floods in 2001 (a wet year; 25 cm winter rain) and 2002 (a dry year; 5 cm winter rain) in the San Pedro River, southeastern Arizona. This hydrologic information was used to evaluate observed patterns in nitrate, dissolved organic nitrogen (DON) and dissolved organic carbon (DOC) concentrations in floods. The first floods of each year showed increased stream nitrate concentration that was approximately two orders of magnitude higher than base flow concentration. DOC consistently doubled to tripled during storm events, while DON in 2001 showed no response and showed a marked increase in 2002. A chloride mixing model indicated that soil and groundwater contributions to storm water discharge were related to antecedent conditions and to flood magnitude. Soil and groundwater contributions were the highest early in the 2001 monsoon season following the wet winter, much lower early in 2002 following a dry winter, and lowest during the largest floods of the 2002 monsoon season when flows were derived primarily from precipitation and overland flow. Stream water nitrate-N concentrations during floods were consistently 0.2–0.5 mg/L higher in 2002 than during 2001, suggesting greater over-winter accumulation of soil nitrate during the drier year. This result is consistent with higher mean nitrate-N concentrations in soil water of the riparian zone in 2002 (3.1 mg/L) than in 2001 (0.56 mg/L). These data highlight the importance of seasonal and interannual variability of hydrology in semiarid regions, and the role of water availability in driving patterns of soil nutrient accumulation and their transport to the stream.
2006
Forecasting potential slope failure in open pit mines – contingency planning and remediation. In Proceedings of the CIM Annual Conference, May 14-17, Vancouver, B.C.
Rose, N.D., & Hungr, O. (2006)
Abstract
Forecasting potential slope failure in open pit mines is integral to maintaining safety and mine productivity. Laboratory testing of rain induced landslides in Japan 20 years ago led to an inverse-velocity approach for estimating slope failure time. This approach appears to have been largely overlooked in mining, but has been successfully applied in the prediction of three large slope failures ranging in size from 1 to 18 million cubic metres. These predictions were forecasted two weeks to three months in advance of failure. This paper provides an overview in the development of inverse-velocity as a tool for failure prediction and presents four case examples in the successful application of this approach. A methodology is also presented that facilitates contingency planning and remediation based on slope movement rate predictions and selection of operational threshold movement rate criteria.
2005
Design and development of the Northeast Layback of the Betze-Post open pit. Pre-print Paper 05-009. 2005 SME Annual Meeting, February 28-March 2, Salt Lake City, UT.
Sharon, R.P., Rose, N.D., & Rantapaa, M. (2005)
Abstract
Development of the Northeast Layback of Barrick’s Betze-Post open pit commenced in June 2000 and was successfully completed to a height of 400m (1,300 ft) in January 2003. Following a brief exploration drilling campaign at the toe of the final slope, in-pit waste rock backfilling commenced, which will ultimately buttress the final wall. Instability initially occurred in late 2000, above the 5040 Level, as the slope height approached 120m (400 ft). As mining reached the 4680 Level, significant deformation was experienced over a slope height of 230m (760 ft). Slope stability was managed and targeted reserve recovery was achieved by executing complicated modifications of the mine plan, including splitting layback development, well placed offloading cuts, step-outs and mid-slope waste rock buttresses. Decision on timing of these modifying events was often dictated by review of deformation magnitudes and rates determined from continuous slope monitoring records. Design modifications were developed through continuing interpretive refinement of structural geology controls and groundwater distribution, and through stability re-assessments.
This document presents an overview of the geological setting and material and strength conditions of the northeast sector of the Betze-Post open pit, followed by development experience leading to design and development of the Northeast Layback. Rock mechanics modeling, design details and geotechnical performance monitoring are then presented. Development experience, stabilizing adjustments to the original design and safety procedures for development and exploration activities are described. The document is finalized with conclusions and acknowledgements.
2004
Mining applications. In D.C. Wyllie & C. Mah (Eds.), Rock Slope Engineering: Civil and Mining (4th ed.) (pp. 357-376). New York, NY: Spon Press.
Stewart, A.F., Hawley, P.M., Rose, N.D., & Gilmore, B.W. (2004)
Groundwater modelling for large-scale mine dewatering in Chile: MODFLOW or FEFLOW? In K. Kovar (Ed.) Proceedings of the FEM-MODFLOW International Conference, September 13-16, Karlovy Vary, Czech Republic.
Alloisio, S., McKittrick, R., Prigneau, P., & Douglas, B. (2004).
Abstract'
This paper reviews and compares the numerical features of MODFLOW and FEFLOW that are specifically relevant to the development of a groundwater flow model for open pit dewatering. Two dewatering models are presented, which were developed using respectively MODFLOW (McDonald and Harbaugh, 1996) and FEFLOW (Wasy Gmbh, 2002), and were used to improve the design of dewatering / depressurisation systems for two large open pit copper mines in Northern Chile. The comparison considers how the two modelling packages represent complex fault systems, dewatering wells, groundwater seepage into the pit and phreatic surface movements during dewatering. Practical considerations on the pre/post-processing facilities and the computational requirements of MODFLOW and FEFLOW in the two applications are also provided.
Development of the Sleeper Pit Lake, Mine Water and the Environment, 23(1), 2-11.
Dowling, J., Atkin, S., Beale, G., & Alexander, G. (2004).
Abstract
The Sleeper open pit gold mine operated from the mid-1980s through the mid-1990s. Operations were mostly sub-water table and extensive dewatering was required to lower groundwater levels by 180 m. Dewatering flows peaked at 930 L/s, with most flow contributed from an alluvial aquifer. After completion of mining, the pit was rapidly filled with water pumped from the alluvial aquifer to reduce the exposure time of sulfide wall rocks and waste rocks in the ultimate pit. The pumped alluvial groundwater provided a large volume of low total dissolved solids (TDS), high alkalinity water that controlled the early chemistry. The rising lake waters were amended with lime to buffer excess acidity contributed to the lake from reactive pit wall rocks during submergence. The pore water contained in submerged waste rock at the base of the pit was elevated in TDS and subsequently of higher density that the lake water. The density contrast and waste rock location limited contributions of waste rock pore water to the main body of the lake. Some stratification of the early lake occurred, with shallow water characterized by higher pH, low dissolved metals, and sulfate; deeper water had lower pH and higher dissolved metals and sulfate. The reservoir of alkalinity in the shallow layer mixed with the deeper waters and created a stabilized lake with a homogenized column that exceeded water quality expectations. Current water quality meets all Nevada primary drinking water standards with the exception of sulfate, TDS, and manganese, which are slightly elevated, as predicted. Chemistry has remained stable since development of the initial lake.
Discrimination of hot versus cold avalanche deposits: Implications for hazard assessment at Mount Meager, B.C. Natural Hazards & Earth System Sciences, 3, 713-724.
Stewart, M.L., Russell, J.K., & Hickson, C.J. (2004)
Abstract
The surficial deposits surrounding the Mount Meager volcanic complex include numerous avalanche deposits. These deposits share many attributes: (a) they are nearly monolithologic and comprise mainly intermediate volcanic rock clasts, (b) they lack internal structure, and (c) they are very poorly sorted. Despite these similarities, the avalanche deposits represent two distinct processes. Mass wasting of the Mount Meager volcanic edifice has produced cold rock avalanche deposits, whereas gravitational collapse of active lava domes and flows has produced hot block and ash avalanche deposits. The ability to discriminate between these "hot" and "cold" avalanche deposits is a critical component in the assessment of hazards in volcanic terranes. Hot block and ash avalanche deposits can be distinguished by the presence of radially-oriented joints, breadcrust textures, and incipient welding, which are features indicative of high emplacement temperatures. Conversely, rock avalanche deposits resulting from mass wasting events may be distinguished by the presence of clasts that preserve pre-depositional weathering and jointing surfaces. Volcanic avalanches are mechanically similar to rock avalanches but pose a greater hazard due to high temperatures, increased fluidization from degassing and the potential to decouple highly mobile elutriated ash clouds. The increasing use of hazardous regions such as the Lillooet River valley requires more reliable risk assessment in order to minimize losses from future hazardous events.
2002
Geotechnical Considerations for Underground Mining of the Dy Deposit, Faro, Yukon. In Proceedings of the CIM Annual Conference, April 28-May 1, Vancouver, B.C.
Rose, N.D. (2002)
Abstract
The Dy deposit is a 21 Mt Pb-Zn-Ag-Au SEDEX-type massive sulphide resource located in the Anvil District, Faro, Yukon. This relatively unexplored orebody lies at a depth of 480 to 920m below surface, dips 20 to 35° and comprises vertical ore thicknesses of 3 to 28m at a 9% Pb + Zn cut-off grade. The deposit has been tested at depth with 63 surface diamond drillholes, but has not yet been explored or developed by underground means. Over the past decade, pre-feasibility investigations were conducted for two separate owners of the property to determine the economic viability of developing an underground mine at Dy. Following these previous studies an assessment was undertaken between 1998 and 2000 to further investigate geotechnical considerations for underground mining. The results and conclusions drawn from this study provide direction for possible future exploration at Dy.
Managing pit slope displacements: Highland Valley Copper’s Lornex Pit southwest wall. In Proceedings of the CIM Annual Conference, April 28-May 1, Vancouver, B.C.
Newcomen, H.W., Maggs, C.S., & Shwydiuk, L. (2002)
Abstract
The southwest wall of the Lornex Pit at the Highland Valley Copper mine has been experiencing slope displacements since 1978. Measures to manage the displacements on previous pushbacks have included stepping out, scheduling pushbacks to unload the crest of unstable areas, slope dewatering and mining with intensive slope monitoring. The final pushback on this wall is currently being mined and substantial modifications to the slope geometry could prove to be uneconomic. As a result, a campaign of surface water collection and diversion, horizontal drainhole drilling and deep well drilling is currently underway to maintain an acceptable degree of stability to the end of mine life. The various factors contributing to instability, including engineering geologic controls, rock mass strength, and surface and groundwater hydrology are presented. Movement trends, displacement magnitudes and stability analyses results are also discussed.
The Importance of Structural Geological Mapping and Slope Monitoring in Open Pit Slope Stability. In Proceedings of the CIM Annual Conference, April 28-May 1, Vancouver, B.C.
Rose, N.D. (2002)
Abstract
The importance of structural geology in open pit slope stability is overlooked in many mining operations due to pressures to cut costs and minimize mine personnel. As a result, mine geology staff are often unable to keep up with geological mapping of the pit slopes due to other day to day production oriented tasks. In some instances, key structural controls that contribute to slope instability may not be identified until after a slope instability has initiated, at which time it may be difficult or impossible to delineate these features in the field. Even for small slopes, understanding the engineering and structural geology of the rock mass, as well as the effects of groundwater and blasting practices, are of key importance to slope stability. Two case histories are presented as examples of mining operations that experienced slope instability with little more than anecdotal information about the structural and groundwater conditions encountered during mining. By conducting field reconnaissance, simple slope stability analyses and ongoing slope monitoring, practical remedial measures were implemented, allowing continued safe mining operation.
Design of the Pierina Waste Dump. CIM Bulletin, 96 (1073), 76-80. Hawley, P.M., Ochoa, X., & Sharon, R. (2002)
Abstract Development of Barrick Gold’s Pierina gold mine in north-central Peru requires construction of a waste dump for disposal of non ore grade materials stripped from the open pit to expose the ore. The waste dump site is located near the open pit in a U-shaped valley that is underlain by thin colluvial and morainal soils with locally thick peats and glaciolacustrine deposits. Bedrock underlying the site consists of variably weathered volcanics. The site is subject to moderately high seasonal rainfall and significant seismicity. The geotechnical quality of the waste rock is highly variable, ranging from low-quality, degradable, soil-like materials containing appreciable quantities of silt and clay, to high-quality, hard, durable, blocky waste rock. A hybrid dump design concept was developed that requires in-pit segregation of high and low-quality waste, and selective placement of materials in the dump to maximize stability and enhance internal and subsurface drainage. The design includes a rock drain beneath the dump along the axis of the valley and a series of connected finger drains. Extensive peripheral diversions and stormwater control measures to inhibit infiltration of precipitation are also included. This paper discusses the unique challenges presented by the site and waste materials, the design methodology and stability analyses, and planned monitoring systems.
Environmental Mitigation Prescriptions. Watershed Restoration Technical Bulletin, Streamline, 6(4), 16-19. Hogarth, J.D., & Hawley, P.M. (2002)
2001
Managing BC’s Groundwater: Protecting and Preserving our Hidden Resource. Innovation, 5(5), 18-21.
Poster Presentation: Changes in concentration and composition of dissolved and particulate organic matter in the upper San Pedro River, Arizona in response to changes in flow regime, American Geophysical Union, Annual fall conference, December, San Francisco, CA.
Haas, P.A. (2001).
2000
Practical rock slope engineering designs at Barrick Goldstrike. In W.A. Hustrulid, M.K. McCarter & D.J.A. Van Zyl (Eds.), Slope Stability in Surface Mining (pp. 213-218). Littleton, CO: SME.
Rose, N.D., & Sharon, R.P. (2000)
Abstract
Over the last decade, there has been an increasing trend in the mining industry towards the use of numerical modeling in open pit rock slope design. This trend has ventured away from more traditional and less time intensive design approaches including: i) limit equilibrium analyses to assess kinematically possible structurally controlled failure mechanisms; ii) limit equilibrium analyses to assess the potential for failure of the rock mass; and iii) empirical assessments of slope stability based on slope height-angle relationships. These more traditional approaches allow a wide variation in parametric analyses to be conducted relatively quickly and as a result, these assessments can often be conducted in a fraction of the time and cost of a numerical modeling design study. In some instances, however, numerical modeling may be required to gain a better understanding of a potential failure mechanism, particularly if deformation analysis is involved. In this situation, the above traditional design tools complemented with numerical modeling may provide a very cost effective and pragmatic approach to open pit rock slope design. To illustrate this design approach, this paper provides a case example of a “practical” slope design application in a very complex geological and hydrogeological environment at the Betze-Post open pit mine in northeastern Nevada.
Site Selection, Characterization and Assessment. In W.A. Hustrulid, M.K. McCarter & D.J.A. Van Zyl (Eds.), Slope Stability in Surface Mining (pp. 267-274), Littleton, CO: SME. [for Waste Dump Embankments]
Hawley, P.M. (2000)
Design, implementation and assessment of open-pit slopes at Palabora over the last 20 years. In W.A. Hustrulid, M.K. McCarter & D.J.A. Van Zyl (Eds.), Slope Stability in Surface Mining (pp. 177-181). Littleton, CO: SME.
Stewart, A.F., Wessels, F., & Bird, S. (2000)
Inflow Testing to Determine the Capacity of the WAC Bennett Dam Blanket Drain. In R. Couture & S.G. Evans (Eds.), Proceedings of the 53rd Canadian Geotechnical Conference: Geotechnical engineering at the dawn of the 3rdmillennium (pp. 57-66), October 15-18, Montreal, QC.
Sobkowicz, J., & Holmes, A.T. (2000)
Abstract
During the Sinkhole Investigation Program, boreholes were drilled into the blanket drain of the WAC Bennett dam. Samples collected by various drilling methods (Sonic, Barber and large diameter drilling) indicated that the blanket drain potentially had a high fines content and thus, by implication, that the capacity of the blanket drain might have been compromised. However, it was recognized that, despite best efforts, the samples might have been contaminated by the drilling itself (a geotechnical application of the Heisenberg uncertainty principle), and thus the high fines content of the samples might be more apparent than real. This led to direct testing of the blanket drain capacity by: a) injection of water at a high inflow rate at the upstream end of the blanket drain, and b) flooding the blanket drain by temporarily damming the discharge and subsequent release of the flooded water. The response of the blanket drain (changing water levels, hydraulic gradients and discharge weir flows) was observed. Drain capacity was demonstrated directly by the large scale injection tests. Drain capacity and material parameters (hydraulic conductivity, storativity) were also determined by 3-D, transient seepage modelling of the injection and flood tests using the computer program MODFLOW.
The Influence of Reduction Reactions and Solids Composition on Pore-Water Concentrations of Arsenic. Environmental Science and Technology, 34(15), 3159-3166.
McCreadie, H., Blowes, D.W., Ptacek, C.J., & Jambor, J.L. (2000)
Abstract
An increasing amount of attention is being focused on the effects of arsenic on health and the factors that control arsenic mobility in groundwater. The release and transport of arsenic below the water table in the current tailings impoundment at Campbell Mine in Balmertown, ON, Canada, are controlled by the reduction of ferric oxide phases within the saturated tailings. The activity of chemolithotrophic bacteria is indicated by enriched δ34S−SO4 ratios, high alkalinity, depleted δ13C−CO3 ratios, and low SO4 concentrations, all of which are consistent with bacterially mediated Fe and SO4 reduction. The concentrations of Fe and As in the tailings porewater increase with depth. This increase is attributed to the bacterially mediated reduction of As-rich hematite and maghemite. The maximum concentrations of Fe and As are 20 and 100 mg/L, respectively. At the bottom of the impoundment, As concentrations decrease sharply to 0.3 mg/L. This decrease in concentration is attributed to reprecipitation of the As as a diagenetic As-bearing sulfide phase.
1999
Mined Rock and overburden piles: Rock drain research program, final report. Prepared with input from Mine Waste Rock Pile Research Committee for Ministry of Energy and Mines, Manalta Coal Ltd., and CANMET.
Piteau Engineering Ltd. (1999)
Estudio Hidrogeológico de la Cuenca del Río Sénia, Castellón-Tarragona. Código: 99001 for the 33rd International Course on Groundwater Hydrology (Curso Internacional de Hidrología Subterránea - CIHS), Universidad Politécnica de Catalunya (July 1999) Association of Road, Channel and Port Engineers of Barcelona.
Piñana, E. (1999).
1998
A Case History Illustrating the Influence That Bench Face Angle Can Have on the Performance of a Highwall Slope. 1998 SME Annual Meeting, Orlando, Florida.
Stewart, A.F., Pearson, M.J. & Savoie, L.M. (1998)
Abstract
Slope design in an open pit mine includes the determination of a number of parameters, including bench height, bench face angle and berm width. By way of a case history of two highwall slopes (160m and 200m high) excavated in dipping strata in an operating coal mine, this paper illustrates the influence that bench face angle can have on the stability of an entire slope. The two highwall slopes, the lower of which experienced significant instability, were excavated in essentially the same lithologic and structural environment, with the main differences between the slopes being the angle at which the bench faces were excavated and the excavating methods that were employed. In addition to describing the instability that occurred on one of the pit walls, relevant aspects of the engineering geology, slope design and excavation procedures are described.
Mining Induced Subsidence Assessments at Jeffrey Mine, Quebec. In Proceedings of the SME Annual Meeting, March 6-8, Orlando, FL.
Martin, D.C., Rose, N.D., & Frigon, D. (1998)
Abstract
Assessment of the potential for mining induced subsidence and determination of ultimate design requirements for a mining operation should be based on a number of assessment approaches. Although the rock mechanics engineer has a variety of limit equilibrium and numerical modeling tools available for assessment and prediction of subsidence effects, empirical approaches based on precedent experience provide a powerful tool for calibration/verification of analytical models and prediction of subsidence.
Three separate analyses approaches have been applied to the assessment of potential subsidence for a proposed block caving mine in eastern Canada. The investigations have included an assessment of documented historical information from previous block cave mining at the site, deterministic analyses using limit equilibrium approaches to assess kinematically possible failure mechanisms, and three-dimensional numerical modeling techniques. Analyses results have been used and compared with precedent experience and documentation of subsidence behavior from previous mining to optimize the subsidence predictions for the proposed mine.
Geochemical Behaviour of Autoclave-Produced Ferric Arsenates and Jarosite in a Gold-Mine Tailings Impoundment. In W. Petruk (Ed.), Waste Characterization and Treatment (pp. 61-78). Littleton, CO: AIME/SME.
McCreadie, H., Janbor, J.L., Blowes, D.W., Ptacek, C.J., & Hiller, D. (1998)
Abstract
Between 1991 and 1994, metallurgical residues from a pressure-oxidation autoclave at the Campbell Au-quartz mine at Red Lake, northern Ontario, were neutralized with dolomite-rich flotation tailings and were deposited in a polyethylene-lined disposal area. Mineralogical analysis indicates that most of the As occurs as a crystalline ferric sulfarsenate, and some is associated with Fe oxides and with K-H30 jarosite. Field pore-water geochemical data from 1994 and 1995 showed increases in Fe(II) and As(III) concentrations, suggesting that the sulfarsenate and jarosite are dissolving; none of the discrete As phases included in a thermodynamic database limit dissolved-As concentrations, and these concentrations may continue to increase. These results demonstrate the potential for Fe and As loading through groundwater systems.
1997
Rock Drain Research Program – Final Report. Prepared for Manalta Coal Ltd., CANMET.
Piteau Engineering Ltd. (1997)
Pit Wall Depressurization in Low Permeability Formations, Mining Engineering, November.
Beale, G., Luther, A.D., & Foster, J. (1997).
Acid Rock Drainage from the Samatosum Waste Dump, British Columbia, Canada. In Proceedings - Fourth International Conference on Acid Rock Drainage – Volume II (pp. 351-366), May 31-June 6, Vancouver, B.C.: Bitech Publishers Ltd.
Ghomshei, M., Holmes, A.T., Denholm, E., Lawrence, R., & Carriou, T. (1997)
Abstract
The Samatosum Silver Mine, located near Barriere, B.C., was operated as a joint venture by Inmet Mining Corporation and Rea Gold Corporation, between May 1989 and September 1992. The mine is presently being reclaimed. Approximately 4 million tonnes of pyrite-rich rock were placed in the waste dump, and potentially acid generating rock was exposed in the footwall and lower hanging wall of the open pit. Water accumulations in the base of the pit have exhibited pH values as low as 2.7, and contain elevated concentrations of manganese and zinc. The waste dump was constructed by layering carbonate-bearing ultra-mafic rocks (MAF) and pyrite-rich potentially acid generating waste (PAG). This waste dump design has led to significant mitigation of acid rock drainage, to the degree that the pH of actual discharge from the dump has remained dominantly neutral through 1996. Elevated metal concentrations observed in seepage from the toe of the waste dump are related to dynamic effects, such as flushing and channeling. Mass balance models for dissolved sulphate, calcium and magnesium loadings in drainage from the waste dump, and the neutral pH that has been maintained to date, suggest that the buffering capacity in the MAF is active and responds proportionately to the rate of pyrite oxidation. This mass balance also indicates that the buffering capacity will persist throughout the period of sulphide oxidation. Non-carbonate buffering capacity, including micas, is also active and responds to low pH conditions inside the waste dump.
X-ray diffraction data suggest that ARD precipitates sampled from the pit walls are dominantly iron oxides, copiopite, gypsum and epsomite. Precipitates are expected to reduce the permeability of the waste rock and further mitigate ARD within the dump. In worst case conditions, waste dump discharge with elevated metals concentrations will be collected and treated along with pit waters. Treatment tests were conducted on pit sump water and waste dump seepage using lime and hydrogen peroxide. A treatment strategy to control ARD form the open pit and waste dump, using lime addition, was implemented in 1996.
Raised Absorption Field Mound Guideline. In Proceedings of Package Wastewater Treatment Technologies and Regulations in British Columbia Seminar, Small Waste Water Systems Committee, B.C. Water and Waste Association, November 13-14, Richmond, B.C.
Holmes, A.T. (1997)
Site Investigation and Evaluation Guideline. In Proceedings of Package Wastewater Treatment Technologies and Regulations in British Columbia Seminar, Small Waste Water Systems Committee, B.C. Water and Waste Association, November 13-14, Richmond, B.C.
Holmes, A.T. (1997)
Pit Wall Depressurization in Low Permeability Formations, Mining Engineering, November.
Beale, G., Luther, A.D., & Foster, J. (1997).
1996
Concepts of Ground Heat Source Systems. – With Reference to the Heat Pump System Installed at the Sandspit Airport, B.C. Paper presented to a seminar on Decentralized Sewage Treatment – Alternatives to the Big Pipe, B.C. Water and Waste Association, Burnaby, B.C., 14pp.
1995
Hydrogeochemistry of Fractured Sedimentary Bedrock of the Southern Gulf Islands of British Columbia, Canada; With Implications for Groundwater Supply. Paper presented to the 26th International Association of Hydrogeologists (IAH) Congress, June 4-10, Edmonton, AB, 6pp.
Jackman Landfill Capping and Biosolids Top Soil Landscaping Project. Presentation given at the 23rd Annual B.C. Water and Waste Association Conference, Whistler, B.C.
Holmes, A.T., Lee, K., & Badke, A. (1995)
1994
Application of Rock Mass Classification to Open Pit Slope Design. In M. Van Sint Jan (Ed.), Integral Approach to Applied rock Mechanics, Volume II, ISRM International Symposium/IV Congreso Sudamericana de Mecanica de Rocas, May 10-14, Santiago, Chile.
Hawley, P.M., Gilmore, B.W., & Newcomen, H.W. (1994)
Abstract
Rock mass classification is a useful tool for evaluating and predicting general ground conditions and response for tunneling and underground mine design. Recently, it has also been used for slope stability assessments and open pit slope design. This paper describes an approach for developing unique, simplified classification schemes tailored to the available data and key site characteristics. Two case studies which illustrate the application of this approach to open pit slope design are described.
Fraser Lowland: Groundwater Resources of the Lowlands and Plains. In Groundwater Resources of British Columbia – Groundwater Section (pp. 9.1-9.29). BC Environment and Environment Canada.
Potential Impacts of Discharged Treated Sewage Effluent on Groundwater Quality. Paper presented to the 1st Conference on Small Waste Water Systems. B.C. Water and Waste Association Conference, 15pp.
1993
Mining an Unstable Slope at the Faro Pit. 1993 CIM Annual General Meeting, Calgary, Alberta.
Stewart, A.F., Vos, G.K. & Cyr, R. (1993)
Groundwater Quality Evaluations of Mines. In Mine reclamation, building confidence: Proceedings of the seventeenth Annual British Columbia Mine Reclamation Symposium (pp. 87-97), Port Hardy, B.C.: Ministry of Energy, Mines and Petroleum Resources. McCreadie, H., & Smith, H.R. (1993)
Abstract Groundwater quality is an aspect of mine reclamation that is now receiving increased attention. The potential impact of mines on groundwater quality can be estimated by considering: mine water sources; groundwater flowpaths; waste characteristics; groundwater geochemistry, and environmental impacts. Primary groundwater flowpaths are within the more permeable geologic materials. These flowpaths can transport a significant mass of contaminants even though they generally comprise a small proportion of the materials. Impacts include potential degradation of water quality in local aquifers, lakes and streams. Groundwater assessments can be carried out in four phases. Phase I consists of a review of existing data that are used to develop a preliminary hydrogeologic interpretation and define a Phase II field program. The preliminary interpretation is verified and a groundwater monitoring network is installed during the field program. The Phase I and Phase II data are amalgamated into a Phase III report, which documents the analysis and presents estimates of future impacts. Mine personnel, in Phase IV, collect and compile monitoring data that can be used to check the model estimates. In this manner, potential environmental liabilities are identified and the costs of remediation and/or mitigation are minimized.
Groundwater Mapping and Assessment in British Columbia, Volume I: Review and Recommendations. DOE FRAP 1993-33. Prepared for Environment Canada Conservation and Protection Fraser Pollution Abatement Office and Resources Inventory Committee Earth Sciences Task Force.
Piteau Associates & Turner Groundwater Consultants. (1993)
1992
A Stability Rating Scheme for Mine Dumps. In Proceedings of the 14th CIM District Meeting, October 1-3, Campbell River, B.C.
Hawley, P.M. (1992)
Groundwater Resources of Swaziland. Report prepared for Canadian International Development Agency (CIDA) and Swaziland Department of Geological Surveys and Mines, 55pp. Piteau Associates Engineering Ltd. (1992)
Renovation of Sewage Effluent Using Ground Disposal Methods. Paper presented to the AQUA-92 National Water Show and Conference, Vancouver, B.C., 15pp.
Characterization of Hydrogeologic Features in Bedrock Dominated Terrain, With Examples from Swaziland. In Proceedings of the International Association of Hydrogeology Symposium, May 10-13, Hamilton, ON.
Vilakati, A., Tiplady, D.J., & Dakin, R.A. (1992)
1991
Numerical modeling studies for design of high rock slopes at Palabora Copper Mine. Seventh Congress of the International Society for Rock Mechanics (pp. 799-804).
du Plessis, L., & Martin, D.C. (1991)
Abstract
An explicit finite difference code, FLAC (Fast Lagrangian Analysis of Continua), which employs a continuum code with a Mohr-Coulomb (no tension) constitutive model is used to model the 750m high open pit mine slopes of Palabora Mining Company. Detailed precision field monitoring surveys are used to calibrate the model and derive preliminary estimates of rock mass strength and deformation parameters. The model is applied to simulation of the mining sequences based on long range mining plans, to predict long term slope behaviour. As mining of the open pit progresses, the rock mass parameters must be reviewed on a regular basis in conjunction with the field survey results and observed slope performance. Access full article.
Rock Mechanics and Slope Design Investigations for the South Pit of the Kennecott Ridgeway Mine, South Carolina. In Proceedings of the SME/AIME Annual Meeting, February 25-28, Denver, CO.
Hawley, P.M., Stewart, A.F., Tod, J.D., & Wolff, L.A. (1991)
Abstract Kennecott Corporation, in joint venture with Galactic Resources Ltd., recently began operation of an open pit gold mining and milling facility near Columbia, South Carolina. The deposit consists of two ore bodies (North and South deposits) hosted in deformed and altered metavolcanics and metasediments of the Carolina Slate Belt. This paper describes the rock mechanics and engineering geology investigations conducted for design of interim, ultimate and final reclamation slopes for the South Pit. Emphasis includes the successful use of drill core orientation techniques to confirm complex geologic structure at depth; the development of a three-dimensional rock mass competency model, incorporating surface mapping data, results of bench mapping documentation, field index testing and laboratory testing; and kinematic assessments for design of optimum slopes.
Mined Rock and Overburden Piles - Investigation and Design of Mine Dumps - Interim Guidelines. Prepared for the British Columbia Mine Dump Committee, May (P.M. Hawley & F.B. Claridge).
Piteau Associates Engineering Ltd. (1991)
Examples of Rock Slope Designs Controlled by Factors Other Than Simple Kinematics. 70th Annual Meeting of the Transportation Research Board, Washington, DC.
Stewart, A.F. (1991)
Construction and Operation of the Tailings Disposal Facility for the Samatosum Mine, British Columbia. In Proceedings of the CIM Annual Conference, April 28-May 2, Vancouver, B.C.
Hawley, P.M., Tod, J.D., & Thiele, B. (1991)
Geotechnical Data Collection for Exploration Geologists, Short course No. 10, 2nd Ed. Geological Association of Canada.
Martin, D.C. (1991)
Potential Impacts of Discharged Sewage Effluent on Groundwater Quality. Paper presented to a seminar on Groundwater Quality, Technical University of Nova Scotia, Vancouver, B.C., 15pp.
Contaminant Migration in Groundwater. Paper presented to a seminar on Groundwater Quality, Technical University of Nova Scotia, Vancouver, B.C., 12pp.
Groundwater Contamination from Agricultural Sources in the Lower Fraser Valley. B.C. Professional Engineer (pp. 30-32), October Issue.
Treatment of Trichloroethylene, 1,2-Dichloroethane, Hexavalent Chromium, and Fluoride Contaminated Wastewater. WERC Consortium for Environmental Education and Technology Development.
Reidel, J., et al. (1991)
Geotechnical Data Collection for Exploration Geologists, Short course No. 10, 2nd Ed. Geological Association of Canada.
Martin, D.C. (1991)
Treatment of Trichloroethylene, 1,2-Dichloroethane, Hexavalent Chromium, and Fluoride Contaminated Wastewater. WERC Consortium for Environmental Education and Technology Development.
Reidel, J., et al. (1991)
1990
Deformation of Open Pit Mine Slopes by Deep Seated Toppling. In Proceedings of the 13th CIM District 6 Meeting, September 6-8, Kamloops, B.C.
Martin, D.C. (1990)
Abstract
The relationships between engineering geology, structural geology, strength properties and failure mechanisms of several large slope failures in western North America are examined. The main failure mechanism identified at each site involves primarily deep seated toppling. Characteristics, diagnostic features and behaviour of each failure are reviewed. Back analyses of two failures using limit equilibrium techniques as well as numerical modelling confirms that the toppling mechanism is extremely sensitive to mining activity and groundwater pressure. Although deep seated toppling failures may involve more than several million tonnes, large deformations of the order of several tens of metres have been documented without catastrophic failure. These deformations are explained from the results of numerical modelling using a distinct element finite difference code. Ongoing research and documentation of such failures is providing a clearer understanding of the deformation behaviour of high rock slopes.
Design of a tailings disposal facility for the Samatosum Mine, British Columbia. In R.K. Singhal & M. Vavra (Eds.), Mine Planning and Equipment Selection 1990 (pp. 433-440), Proceedings of the 2nd International Symposium on Mine Planning and Equipment Selection, November 7-9, Calgary, AB.
Hawley, P.M., & Stewart, A.F. (1990)
Engineering Geology and Rock Mechanics Assessments of Slope Deformation and Slope Instability in the Cassiar Open Pit. CANMET Project No. 9-9227, June.
Martin, D.C. (1990)
Deep Open Pit Mines. In J. Franklin (Ed.), Mine Monitoring Manual (pp. 13-25). Special Report 42. Ste-Anne-de-Bellevue, Québec: The Canadian Institute of Mining and Metallurgy.
Martin, D.C., & Franklin, J. (1990)
Practical Aspects of Hydrogeology Studies for Hydrocarbon Migration in British Columbia. In Weyer (Ed.), Subsurface Contamination by Immiscible Fluids (pp. 465-474), Proceedings of the International Conference on Subsurface Contamination by Immiscible Fluids, April 18-20, Calgary, AB: A.A. Balkema.
Dakin, R.A., Holmes, A.T., & Tiplady, D.J. (1990)
Abstract
Over the last three years, there have been numerous leaks and accidental spills of a variety of hydrocarbon compounds into the ground in southern British Columbia. In the course of searching for and delineating the flow paths of these fugitive hydrocarbons, the writers have reached conclusions with practical implications that may interest other investigators. In the following paper a brief introduction is presented for four case histories, and one or two unique aspects of either the investigative approach or interpretation of results are described. The examples involve leaks of gasoline and spills of xylene and ethylene dichloride. Descriptions are given of buried underground services acting as gasoline traps, tidal influences making the interpretation of groundwater flow direction more complex, fluid density causing distortions in interpretation of piezometric head, and a drawdown cone around a nearby well causing an apparent bifurcation of a floating hydrocarbon plume. At one site, measurement of thickness of hydrocarbon saturated sand in drill core was compared with thickness of floating hydrocarbon fluid in a completed monitoring well. After applying appropriate corrections to the hydrocarbon thickness measured in the well, this value was generally in close agreement with that measured in the saturated sand sample.
Groundwater Quality Monitoring Manual. B.C. Ministry of Environment, Environmental Protection Division, March.
Piteau Associates Engineering Ltd. (1990)
Water Pressures and Flows. In J. Franklin (Ed.), Mine Monitoring Manual (pp. 124-130). Special Report 42. Ste-Anne-de-Bellevue, Québec: The Canadian Institute of Mining and Metallurgy.
Barron, K., & Knapp, R. (1990)
Water and Air Quality. In J. Franklin (Ed.), Mine Monitoring Manual (pp. 131-134). Special Report 42. Ste-Anne-de-Bellevue, Québec: The Canadian Institute of Mining and Metallurgy.
Dainty, D., Bigu, J., Cain, P., & Dakin, R.A. (1990)
Practical Aspects of Hydrogeology Studies for Hydrocarbon Migration in British Columbia. In Weyer (Ed.), Subsurface Contamination by Immiscible Fluids (pp. 465-474), Proceedings of the International Conference on Subsurface Contamination by Immiscible Fluids, April 18-20, Calgary, AB: A.A. Balkema.
Dakin, R.A., Holmes, A.T., & Tiplady, D.J. (1990)
Abstract
Over the last three years, there have been numerous leaks and accidental spills of a variety of hydrocarbon compounds into the ground in southern British Columbia. In the course of searching for and delineating the flow paths of these fugitive hydrocarbons, the writers have reached conclusions with practical implications that may interest other investigators. In the following paper a brief introduction is presented for four case histories, and one or two unique aspects of either the investigative approach or interpretation of results are described. The examples involve leaks of gasoline and spills of xylene and ethylene dichloride. Descriptions are given of buried underground services acting as gasoline traps, tidal influences making the interpretation of groundwater flow direction more complex, fluid density causing distortions in interpretation of piezometric head, and a drawdown cone around a nearby well causing an apparent bifurcation of a floating hydrocarbon plume. At one site, measurement of thickness of hydrocarbon saturated sand in drill core was compared with thickness of floating hydrocarbon fluid in a completed monitoring well. After applying appropriate corrections to the hydrocarbon thickness measured in the well, this value was generally in close agreement with that measured in the saturated sand sample.
1989
Monitoring of Water Pressures and Inflows. In Handbook on Mine Monitoring. Prepared by Rock Mechanics and Strata Control Committee of Canadian Institute of Mines, 10pp.
Identification, evaluation and mitigation of debris flow hazards in British Columbia. In Erosion knows no boundaries, Proceedings of Conference XX, International Erosion Control Association, February 15-18, Vancouver, B.C.
Hawley, P.M. (1989)
1988
Footwall Anchoring at Smoky River Coal Limited. CIM Bulletin, 81(915), 78-85.
Fawcett, D.A., Sheehan, P.L., & Martin, D.C. (1988)
Abstract
Smoky River Coal Limited has successfully completed a major program involving the pattern rock anchoring of a high, steeply-dipping footwall slope. The slope dips at approximately 65 to 70 degrees to the north, is benched for the upper 200 feet, is supported with rock anchors for another 240 feet, and is unsupported at the pit bottom. In addition to the height and steepness, several structural features including shears, rolls and stratigraphic pinchouts complicate footwall stability. This paper presents an overview of the project with descriptions of the engineering geology and footwall design, anchor installation, instrumentation and monitoring and a cost summary.
Preliminary Geotechnical and Mine Planning Investigations for the Judy Creek South Coal Project, Alberta. In R.K. Singhal (Ed.), Mine Planning and Equipment Selection (pp. 129-136), Proceedings of an International Symposium on Mine Planning and Equipment Selection, November 3-4, Calgary, AB.
Hawley, P.M., Claridge, F.B., & Lutley, H.J. (1988)
Geotechnical and Hydrogeological Requirements for Development of Mining Projects in British Columbia. Mining Review, July/August.
Stewart, A.F., & Martin, D.C. (1988)
Hydrogeological Studies in Southern Lowveld Area, Swaziland. In C.L. Lin (Ed.), Proceedings of International Groundwater Symposium on Hydrogeology of Cold and Temperate Climates and Hydrogeology of Mineralized Zones (pp. 52-59), May 1-5, Halifax, NS.
Vilakati, A., & Balfour, J.D. (1988)
Abstract
The Government of Swaziland, with the assistance of the Canadian International Development Agency (CIDA) and their consultants Piteau Associates Engineering Ltd., is carrying out a groundwater survey of the entire country. The field program, which commenced in March, 1986 in the arid Lowveld area, is planned to continue until March 1991.
In this paper the equipment used to explore for groundwater in Permian-Jurassic aged sedimentary, intrusive and volcanic rocks of the region is described. All 145 boreholes completed by the end of September were rock holes, with only a few required liners to stabilize the borehole walls. Borehole depths range from about 10 to 305m, with an average of 106m. Yields range from less than 0.01 up to 10 L/s, with an average of about 1.2 L/s. Groundwater is generally a very hard calcium-magnesium bicarbonate type water, with moderately high levels of naturally occurring nitrate (max 50 mg/L) and fluoride (max 5 mg/L) in some localities. Results to date suggest that small quantities of groundwater can be developed from discontinuous water bearing zones in all regions of the Swaziland Lowveld; however, siting our boreholes relative to specific targets is absolutely critical for a reasonable success rate. Potential targets include leached bedrock zones, associated with faults and/or dolerite dykes, and zones of deep weathering in basaltic rock.
Investigation and Development of a Supplementary Groundwater Source for the Village of Fruitvale, B.C. Paper presented to the 16th Annual B.C. Water and Waste Association Conference, Whistler, B.C.
Dakin, R.A., & Holmes, A.T. (1988)
Geotechnical and Hydrogeological Requirements for Development of Mining Projects in British Columbia. Mining Review, July/August.
Stewart, A.F., & Martin, D.C. (1988)
Monitoring, Migration and Control of an Ethylene Dichloride Contaminant Plume in a Gravel Aquifer. In C.L. Lin (Ed.), Proceedings of International Groundwater Symposium on Hydrogeology of Cold and Temperate Climates and Hydrogeology of Mineralized Zones (pp. 41-50), May 1-5, Halifax, NS.
Dakin, R.A., & Holmes, A.T. (1988)
Abstract
On February 15, 1986, derailment of a CN Rail freight train near Fort Langley, B.C. resulted in a 247,500 litre spill of ethylene dichloride (EDC). Within a few hours, the spilled chemical had seeped into the ground.
Piteau Associates were retained to supervise a drilling program that was carried out to delineate the extent of the contamination and to establish a monitoring network. A monitoring program was instituted to determine temporal changes and to determine the direction and velocity of contaminant migration. Initial monitoring indicated that a plume in a gravel aquifer was travelling towards the Fraser River, about 350m away, at a maximum rate of about 2.5m/day. Many plastics, (such as PVC) which are normally used for groundwater monitoring, could not be used due to the corrosive nature of the EDC. Readily available steel and non corrosive plastic materials were used to avoid delays in implementing a monitoring system. The hydraulics of the aquifer were analyzed, and the pumping rate required to control migration of the plume was estimated. Subsequent to this study, a recovery program was instituted by others, and recovery of the EDC is still ongoing.
1987
Design of Open Pit Coal Mine Slopes: An Integrated Approach. International Journal of Surface Mining, Reclamation and Environment, 1(3), 179-185.
Hawley, P.M., & Stewart, A.F. (1987)
Abstract
Many of the coal deposits of Western Canada exhibit intensely folded and/or faulted strata. Geological evaluation of such deposits is often difficult and uncertain, and interpretations are subject to significant modifications throughout the exploration, development and mining phases. Design and excavation of open pit slopes under such conditions can present a variety of operational and slope stability problems. Slope design approaches and excavation procedures which are flexible and capable of adapting to changing conditions are essential for rational slope development.
This paper examines the problems associated with open pit coal mine slope design in complex geologic environments. A systematic approach to slope design which incorporates engineering geology assessments, slope stability analyses, economic evaluations and mining operational constraints is presented. Slope design concepts which utilize a variety of slope development techniques, including benching and artificial support are developed. The design process continues throughout the mining phase in an iterative cycle whereby slope designs are prepared and implemented, remedial measures are applied, existing slopes are documented and evaluated, and slope design concepts and subsequent slope designs are updated and modified as necessary.
Engineering Geology Approach to Assessment of Kinematically Possible Failures in Stopes. In Proceedings of the CIM Annual Conference, May 3-7, Toronto, ON.
Martin, D.C., & Hawley, P.M. (1987)
Abstract
One of the most important controls on the stability of underground openings is the possible development of large blockfalls formed by the intersection of geologic structural discontinuities. The presence of unfavourably oriented major discontinuities such as faults, shears or dykes can lead to large blockfalls which could result in loss of the stope. In addition, blockfalls arising from a combination of minor discontinuities can result in unsafe working conditions and ore dilution.
This paper describes an approach to defining and assessing possible failure modes involving geologic structural discontinuities. Several examples illustrating the application of this approach to the design of backs, sidewalls and pillars in stopes are presented.
Remedial Measures for the Marmot J Seam Footwall Slope at Quintette Coal Limited’s Mesa Mine. In Proceedings of the 11th CIM District 6 Meeting, October 21-31, Vancouver, B.C.
Stewart, A.F., Hawley, P.M., & Tassie, P. (1987)
Abstract
The Marmot J Seam Footwall at Quintette Coal Limited’s Mesa Mine dips at less than 25° to about 55°. At a number of locations on the wall, unfavourably oriented faults have offset the footwall in such a manner as to undercut relatively low strength bedding planes. In June, 1986 a planar failure, extending the full 70m height of the footwall, occurred along one of these undercut bedding planes. This paper describes the engineering geology of the footwall and the remedial measure implemented to rehabilitate the failed portion of the footwall. Also included are discussions concerning the analyses, design and initial implementation of remedial measures for the remainder of the footwall, which will ultimately be up to about 200m high.
Monitoring, Migration and Control of an Ethylene Dichloride Contaminant Plume in a Gravel Aquifer. Proceedings of Geotechnique in Resource Development Conference, Canadian Geotechnical Society. Regina, Saskatchewan.
Dakin, R.A., Holmes, A.T. 1987
1986
Application of a rock buttress to design of slopes at Cassiar Mine. CIM Bulletin, 79(896), 60-66.
Martin, D.C., & Carew, T.J. (1986)
Abstract
One approach to stabilization of rock slopes is to place a buttress at the toe of the slope to provide additional resisting forces and increase the length and strength properties along the failure surface. This paper describes the rock mechanics and mine planning aspects of incorporating a buttress of intact rock in the lower part of the slope as part of the slope design for the south wall of the final pit at Cassiar Mine. Stability analysis techniques and results are described. Analyses results have indicated that, in order to maintain steep over-all slopes in the final pit, a buttress of intact rock should be incorporated into the lower section of the slope until late in mine life. The effect of the buttress is to flatten the slope and reduce the slope height thereby improving slope stability. The mining plans would be such that the buttress would be mined out during the last four months of mining, when the consequences of instability would be least severe.
Application of a statistical analysis technique for design of high rock slopes at Palabora mine, South Africa. Mining Latin America (pp. 241-255).
Martin, D.C., Steenkamp, N.S.L. & Lill, J.W. (1986)
Abstract
This paper describes the engineering geology, structural geology, stability analysis, and design of slopes for the open pit copper mine of Palabora Mining Company located in South Africa. The pit occurs in generally hard, jointed rock. Because of the large size, low grade and geometry of the orebody, it is imperative to minimize the waste to ore ratios and hence mine to stringent plans incorporating maximum safe working slope angles.
Stability of interramp slopes in most areas is controlled by numerous possible wedge and plane failures on benches. Stability analyses were conducted by dividing the pit into design sectors. A unique statistical analysis technique which combines the results of limit equilibrium analysis of each potential failure mode with orientation and intensity of discontinuity populations was used to design benches and interramp slopes in each design sector. The statistical significance of each failure mode was assessed using cumulative frequency plots. Slope design charts were developed based on slope geometry and failure geometry. The effects of observed bench break back and documented behaviour of slopes were also incorporated into the analysis to enable preparation of an effective slope design. Implementation of the slope design technique for 200 to 350m high slopes which have been excavated at Palabora is reviewed and the slope performance is assessed from both an operations and stability perspective.
Failure Mechanics and Design Considerations for Footwall Slopes. CIM Bulletin, 79 (896), 47-53.
Hawley, P.M., Martin, D.C., & Acott, C.P. (1986)
Abstract
In bedded deposits such as coal or sedimentary iron, economic limits of mineable reserves are clearly defined by the footwall of the seams or ore-bearing units. Where open pits are developed in dipping strata, a long, high footwall slope may result. In many cases, unbenched slopes excavated along the base of the lowest mineable seam are operationally simple, economically desirable and geotechnically practical, although a variety of failure mechanisms may develop. This paper examines the engineering geology and rock mechanics parameters of importance in the design of footwall slopes. Possible failure mechanisms and stability analysis methods are described. Design considerations for benched and unbenched slopes are discussed with prime consideration given to development of long high slopes without benches or with a minimum number of benches.
Mine Waste Dumps Constructed in Mountain Valleys. CIM Bulletin, 79 (892), 79-87.
Claridge, F.B., Nichols, R.S., & Stewart, A.F. (1986)
Abstract
In recent years, an increasing number of mines in mountainous terrain have examined the possibility of placing mine waste rock into stream valleys. Pressure to utilize stream valleys as a primary location for waste disposal has increased at many of the mines currently under development or expansion. As the number of environmentally and economically ideal waste dumping sites is limited, consideration must be given to utilization of stream valleys. This raises concerns about maintaining water quality in streams passing through or beneath the dumps and potential detrimental effects to dump stability. Commonly, the flows in the streams tend to be flashy, reflecting localized intense storms and rapid runoff in steep-sided slopes within the watershed. These conditions pertain particularly to British Columbia, which is characterized by mountainous terrain and periodically intense precipitation events.
The method of conveying flow through a waste dump depends on a number of geotechnical and hydrological factors, including the size, durability and transmissivity of the rock and the design stream flood flow. This paper describes the approach to the design of waste dumps in stream valleys developed at several mines in British Columbia.
1985
A Combined Limit Equilibrium and Statistical Analysis of Wedges for Design of High Rock Slopes. In C.H. Dowding (Ed.), Rock Masses (pp. 93-105), Geotechnical Engineering Division Symposium, ASCE Convention, April 28-30, Denver, CO.
Piteau, D.R., Stewart, A.F., Martin, D.C., & Trenholme, B.S. (1985)
Abstract
This paper describes a unique technique developed for the statistical analysis of wedge failures which control the design of high slopes in relatively hard jointed rock masses. Using this technique, kinematically possible wedges, formed by various combinations of structural discontinuities, are identified and assessed statistically. This is accomplished by quantifying the variation in orientation and intensity of individual discontinuity sets as they affect the frequency and orientation of kinematically possible wedge failures.
The analysis technique incorporates a) geologic structural characteristics of the rock mass; b) kinematically possible wedge failures; and c) limit equilibrium analysis results, all of which are treated statistically. The cumulative percentage frequency of possible wedges is plotted against apparent plunge of possible wedges with respect to the slope. The factor of safety of the wedges is also plotted. These cumulative frequency plots, which are distinctive for a particular rock mass and a particular slope orientation, are used as a basis for slope design using specially developed slope design charts. A working example of slope design based on this technique is presented.
Geotechnical Assessments and Design of Optimum Method for Excavation of a Footwall Slope at Smoky River Coal Limited. In Proceedings of the 2nd CIM District 5 Meeting, September, Hinton, B.C.
Martin, D.C., Sheehan, P.L., & Fawcett, D.A. (1985)
Preservation of Groundwater Quality in British Columbia: Be Vigilant Now and Avoid a Lot of Problems Later. Paper presented to the B.C. Water and Waste Association Annual Conference, Penticton, B.C., 11pp.
Photo Voltaics for Water Pumping in Developing Countries. B.C. Professional Engineer (pp. 12-15).
Potential Impacts of Discharged Treated Sewage Effluent on Groundwater Quality. In Proceedings of the B.C. Water and Waste Association Spring Seminar, June 3-4, Richmond, B.C., 14pp.
A Combined Limit Equilibrium and Statistical Analysis of Wedges for Design of High Rock Slopes. In C.H. Dowding (Ed.), Rock Masses (pp. 93-105), Geotechnical Engineering Division Symposium, ASCE Convention, April 28-30, Denver, CO.
Piteau, D.R., Stewart, A.F., Martin, D.C., & Trenholme, B.S. (1985)
Abstract
This paper describes a unique technique developed for the statistical analysis of wedge failures which control the design of high slopes in relatively hard jointed rock masses. Using this technique, kinematically possible wedges, formed by various combinations of structural discontinuities, are identified and assessed statistically. This is accomplished by quantifying the variation in orientation and intensity of individual discontinuity sets as they affect the frequency and orientation of kinematically possible wedge failures.
The analysis technique incorporates a) geologic structural characteristics of the rock mass; b) kinematically possible wedge failures; and c) limit equilibrium analysis results, all of which are treated statistically. The cumulative percentage frequency of possible wedges is plotted against apparent plunge of possible wedges with respect to the slope. The factor of safety of the wedges is also plotted. These cumulative frequency plots, which are distinctive for a particular rock mass and a particular slope orientation, are used as a basis for slope design using specifically developed slope design charts. A working example of slope design based on this technique is presented.
1984
Demonstration of Shield-Type Longwall Supports at Kaiser Steel Corporation's Sunnyside No. 1 Mine, Utah. AIME Fall Meeting, October 24-26, Denver, CO. (Condensed from USBM Contract Report, May 1983).
Hawley, P.M., & Hood, M. (1984)
[Access full article.][31] [31]: http://www.onemine.org/document/abstract.cfm?docid=175997
Remedial measures for debris flows at the Agassiz Mountain Institution, British Columbia. Canadian Geotechnical Journal, 21(3), 505-517.
Martin, D.C., Piteau, D.R., Pearce, R.A., & Hawley, P.M. (1984)
Abstract
On the evening of January 23, 1982 a debris flow having an estimated volume of 11,000m3 occurred in a stream channel on the south slope of Mount Agassiz adjacent to the Mountain Institution of the Correctional Services of Canada. The debris flow was one of many that have contributed to the formation of a large debris fan at the base of the mountain. Debris flows, large rockfalls, and other events can be expected to occur intermittently as part of the ongoing natural erosional processes in steep mountainous terrain. The paper describes the site investigation and analyses carried out and the design and construction of remedial measures to control future debris flows and rockfalls. Remedial measures consisted of improvement of stability of two large rockfall blocks in the debris flow channel using grouted dowels. In addition, two berms and a containment basin were constructed on the debris fan to control future debris flows and rockfalls.
1983
Origin of Dissolved Solids in Ground Waters of Mayne Island, British Columbia, Canada. Journal of Hydrology, 66 (3-4), 233-270.
Farvolden, R.N., Cherry, J.A., & Fritz, P. (1983)
Abstract
Hydrogeological, hydrochemical and isotope techniques were applied to determine the origin of saline groundwaters on Mayne Island in the Strait of Georgia, British Columbia. The saline groundwater is a sodium chloride type, with concentrations of Na+ and Cl− as high as 4367 and 8008 mgl−1, respectively. Leach tests on twenty rock samples from boreholes indicate that the shale strata in the Cretaceous bedrock have Cl−concentrations ranging up to 900 ppm by weight and Na+ concentrations up to 2070 ppm. The salt probably originated in the shale during periods of post-depositional compaction, or during periods of immersion in ocean water during episodes of glacial loading and erosion during Pleistocene time. The present flow regime of active flushing of meteoric water through the surficial sediments and sedimentary bedrock of Mayne Island began as the island emerged from below sea level during the last deglaciation. The salt content of the present-day groundwater can be accounted for by the slow release, through molecular diffusion, of Na+ and Cl− from the low-permeability matrix of the shale to the active paths of groundwater flow in fractures in the shale and in sandstone strata. Intrusion of ocean water under the present hydrologic regime on the island, and upward flow of brine from deep zones within the regional sedimentary basin are believed to be relatively unimportant contributors of salt to the active groundwater flow systems. 18O, deuterium and tritium concentrations are rather uniform for both surface waters and groundwaters on Mayne Island and a meteoric origin is suggested. Saline spring waters on an adjacent island were found to have high 18O and D concentrations, suggesting a sedimentary basin brine, but there is no evidence that these brines are mixing with Mayne Island groundwater.
Microcomputers Applied to Groundwater Resource Modelling. Paper presented to the B.C. Water and Waste Association, Richmond, B.C.
Holmes, A.T., & Dakin, R.A. (1983)
Mechanics of Rock Slope Failure, in: 3rd Stability in Surface Mining. Presented at the 3rd Stability in Surface mining, American Institute of Mining, Metallurgical and petroleum Engineers, p. 23.
Piteau, D.R., & Martin, D.C. (1983).
1982
Hydrogeology of Municipal Landfills; With Reference to Situations in British Columbia. Paper presented to the seminar on landfills, Greater Vancouver Regional District, October 21, North Vancouver, B.C., 55pp.
Mechanics of rock slope failure. In C.O.Brawner (Ed.), Stability in Surface Mining Volume 3, Proceedings of the Third International Conference on Stability in Surface Mining (pp. 113-169), June 1-3, Vancouver, B.C., New York, NY: SME-AIME.
Piteau, D.R., & Martin, D.C. (1982)
Abstract
Instability of rock slopes may occur by failure along pre-existing structural discontinuities, by failure through intact material or by failure along a surface formed partly along discontinuities and partly through intact material. Although certain fundamental failure modes are recognized, the mechanisms of slope failure are varied and complex. Such mechanisms are governed by the engineering geology conditions of the rock mass, which are almost always unique to a particular site. An understanding of failure mechanisms requires a knowledge of the physical, mechanical and strength properties of the intact material and discontinuities which make up the rock mass, as well as the structural geology and hydrogeology. These engineering geology parameters also must be evaluated with respect to the slope geometry to determine failures which are kinematically possible. Only after obtaining a reasonable appreciation of the possible failure modes can a rational mechanical stability analysis be carried out.
Both two-dimensional and three-dimensional failure mechanisms should be considered in assessing the design of rock slopes. Simple analyses methods are used initially to identify those possible failures which could control slope stability. More complex and detailed analyses usually are required for a few critical failure modes which could control stability, or where a more complex type of failure mechanism is envisaged. Complex failure mechanisms are usually identified when assessing previous slope failures. More detailed information concerning slope geometry and engineering geology parameters must be acquired where analyses must be more rigorous.
1981
Design Examples of Open Pit Slopes Susceptible to Toppling. In C.O.Brawner (Ed.), Stability in Surface Mining Volume 3, Proceedings of the Third International Conference on Stability in Surface Mining (pp. 679-712), June 1-3, Vancouver, B.C., New York, NY: SME-AIME.
Piteau, D.R., Stewart, A.F., & Martin, D.C. (1981)
Abstract
Three examples of open pits where toppling failure controls the stability and design of the slopes are described. Two examples involve the design of overall slopes in base metal mines. The third example concerns the analysis and design of remedial measures to prevent toppling failure from occurring in a critical slope in a coal mine.
The analytical techniques for assessing toppling failure on a rational basis are discussed for the three examples. This includes an assessment of the important parameters which govern the stability for the toppling failure mode. The geological setting and input data for each example are described, as are the important external or limiting factors pertinent to the sites in question. A statistical cumulative technique was used to assess one of the most important input parameters in the two examples involving overall slope design. Both deep-seated toppling failures, involving the entire slope, and shallow bench failures are considered. Results of the stability analyses and their related engineering significance with regard to slope stability and design are discussed. A sensitivity analysis of various parameters is effectively utilized. Design charts are developed and evaluated accordingly. In the example where toppling failure was unavoidable, the rationale for design of stabilization techniques to prevent toppling is discussed.
1979
Rock Slope Engineering Reference Manual. Part A to Part H. Report No. FHWA-TS-79-208 NTIS Accession Numbers PB80 103-294, -310, -328, -336, -349, -351, -369, -377. Course reference manuals.
Piteau, D.R., Martin, D.C., and Stewart, A.F. (1979)
Introduction to Groundwater Hydrology. In Proceedings of the B.C. Water and Waste Association Seminar on Groundwater, January 15-16, Burnaby, B.C., 25pp.
Rock Slope Engineering Reference Manual. Part A to Part H. Report No. FHWA-TS-79-208 NTIS Accession Numbers PB80 103-294, -310, -328, -336, -349, -351, -369, -377. Course reference manuals. Piteau, D.R., Martin, D.C., and Stewart, A.F. (1979)
1978
Engineering of Rock Slopes. In R.L. Schuster & R.J. Krizek (Eds.), Landslides Analysis and Control (pp. 192-234). Special Report 176. Washington, D.C.: Transportation Research Board, Commission on Sociotechnical Systems, National Research Council, National Academy of Sciences.
Piteau, D.R., & Peckover, F.L. (1978)
1977
Select Berm Width to Control Local Failure, Engineering and Mining Journal, 178 (6), 161-164.
Martin, D.C., & Piteau, D.R. (1977)
Abstract
Stability analyses for open pit slope design must consider the possibility of the failure of individual benches as well as the failure of the overall slope. In many cases, the probability of overall slope failure along major faults or weak ones may prove to be small, while the design of individual benches against excessive failure may be the controlling factor for design of the overall slope. Small failures can cause major disruptions to pit operations and can limit accessibility. A graphical method for design of individual benches to control small failures is described here.
Slope Stability Analysis and Design Based on Probability Techniques at Cassiar Mine. CIM Bulletin, 70 (779), 139-150.
Piteau, D.R., & Martin, D.C. (1977)
Abstract
This paper describes the open-pit studies relating to slope stability and design of the argillitic waste rocks which form the upper 700 feet of the 1000 to 1100 ft high hanging-wall slope at the Cassiar Mine. Analyses indicated that the likelihood of deep-seated failure in terms of slope angles which are geometrically possible was low. However, wedge failures on benches, which involve either whole or parts of the benches, were found to be of principal importance with respect to stability.
Slope stability analyses and related slope design were based essentially on evaluating the geometry of the potential wedge failures in terms of the probability of occurrence of unstable wedge failures which could spill over the berms01. Probability theory is developed and applied in such a way that the possibility of benches on the slope becoming ineffective is evaluated and related to overall slope design. The probability of possible wedge failures spilling over berms of various widths, which are a function of the bench geometry, geometry of the possible failure, overall slope angle and angle of repose of material involved in the possible wedge failures, is considered. Based on this approach, mine management could evaluate alternative slope designs and decide themselves on what probability of bench failure they feel is acceptable for their particular mining operation.
1976
Regional Slope Stability Controls and Related Engineering Geology for the Fraser Canyon, British Columbia. In D.R. Coates (Ed.), Landslides, Geological Society of America.
Piteau, D.R. (1976)
Abstract
A study of the 68-mi (109-km) section of the Fraser Canyon between Lytton and Hope, British Columbia, along the Canadian National Railway (CNR) was made to determine what factors controlled slope stability on a regional scale. Engineering geology aspects concerning regional faulting and related minor structure, lithology, drainage and hydrology, geomorphology, climate, river geometry, and effects of man were considered. The most significant cause of slope instability was deflecting of the Fraser River into its bank by the presence of either an alluvial fan at a tributary mouth or a river bend. This deflection allowed extensive lateral erosion and resulted in severe oversteepening, which undermined the toe of the slope. Rockfalls, rock and debris slides, and wash-outs have been recorded for more than 20 years by the CNR. These data indicate that about 66% of all such incidents occurred opposite alluvial fans or on outside curves of the river. The average numbers of incidents per mile occurring opposite alluvial fans and on the outside of river bends are 5.6 and 3.3 times greater, respectively, than the average number of incidents recorded for river stretches without these characteristics. Regional faulting, climatic conditions, and effects of man were also found to be important causes of slope instability.
Significance of River Morphology on Slope Stability in the Fraser Canyon. Proceedings of the 29th Canadian Geotechnical Conference, Canadian Geotechnical Society, October 13-16, Vancouver, B.C.
Piteau, D.R. (1976)
Abstract
A study of the 68-mile section of the Fraser Canyon between Lytton and Hope indicated that alluvial fans and river directional changes are the major causes of regional slope stability problems. Deflection of the river into the opposite bank has resulted in severe oversteepening and undermining of the toe of the slope, due to intensive lateral scouring effects. Although alluvial fan and river directional effected areas involve less than 1/3 of the canyon length, comparative analysis of the number of incidents of rockfalls, landslides, debris slides and washouts which have been recorded during the past 30 years, indicate that about 66% of all incidents occur in these localities. The average number of incidents per mile occurring in localities effected by alluvial fans and river directional changes is 5.6 and 3.3 times greater, respectively, than incidents recorded in localities unaffected by this phenomenon. The same general relationship exists with regard to major inter-glacial and/or post-glacial landslides in that about 60% occur in areas affected by severe lateral river erosion. Also, comparative analysis indicate a high percentage of recorded incidents of instability occur in areas where major landslides have occurred.
Application of Waviness of Structural Discontinuities to Rock Slope Design. Proceedings of the 29th Canadian Geotechnical Conference (pp. 8.1-8.17), Canadian Geotechnical Society, October 13-16, Vancouver, B.C.
Martin, D.C., & Piteau, D.R. (1976)
Overturning Rock Slope Failure at Hell’s Gate Bluffs. In B. Voight (Ed.), Geology and Mechanics of Rock Slides and Avalanches, Amsterdam: Elsevier.
Piteau. D.R., McLeod, B.C., Parkes, D.R., & Lou, J.R. (1976)
1974
Plan Geometry and Other Factors Relating to Natural Rock Slope Stability Applied to Design of DeBeers Mine. Mines Branch, Canada Department of Energy, Mines and Resources, Report TB 190, 120p.
Piteau, D.R. (1974)
Plan Geometry and Other Factors Relating to Natural Rock Slope Stability Applied to Design of DeBeers Mine. Mines Branch, Canada Department of Energy, Mines and Resources, Report TB 190, 120p.
Piteau, D.R. (1974)
1973
Characterizing and Extrapolating Rock Joint Properties in Engineering Practice. Rock Mechanics (pp. 5-31), Supp. 2
Piteau, D.R. (1973)
Abstract
The engineering properties of a rock mass are influenced, often for the largest part, by the joints and other discontinuities within the mass. To determine and evaluate these properties it is necessary, therefore, that an acceptable method of sampling, processing and interpreting the joint population be used. Any extrapolation of these properties to other portions of the mass requires that the region to which extrapolation applies is delineated. This requires in part that certain important aspects such as regional tectonic history and joint patterns, genesis of jointing, assessment of structural controls, and so forth, are considered.
1972
Engineering Geology Considerations and Approach in Assessing the Stability of Rock Slopes. Bulletin of the Association of Engineering Geologists, 9 (3), 301-320.
Piteau, D.R. (1972)
Abstract
Assessing the stability of a slope cut in rock is basically a problem of engineering geology-geology, because it involves a sound understanding of the important aspects of geology, such as geological structure, groundwater, weathering, and other natural phenomena, which all relate to or exist in a geological environment, and engineering, in that quantitative evaluations and calculations are necessary, these being based on mechanics and relating to the strength of the geological materials and the forces causing instability of the slopes.
The engineering geologist must make every attempt to provide, in a quantitative way, information on those geological factors which are necessary for making calculations of the probable stability of the slope. These include numerical assessments of quantities relating to the characteristics of structural discontinuities, rock types, topography, hydrogeology, tectonic history and other environmental factors.
Based upon the development and extension of these general principles, both preliminary and final slope stability studies of some open pits in South Africa, Swaziland, and Zambia have been conducted. Some of the basic concepts and techniques developed to carry these studies out are described.
Engineering Geology Aspects Relating to Preliminary Damsite Investigations on the Nelson River, Manitoba. Canadian Geotechnical Journal, 9 (3), 304-313.
Piteau, D.R. (1972)
Abstract
Engineering geology aspects of the preliminary investigation of nine alternative damsites along the lower reach of the Nelson River between Split Lake and Hudson Bay, Manitoba, Canada area described. Glacial drift, comprising mainly ablation and basal till, almost completely blankets the area, and active slope failures are common. The western part of the area is underlain by Precambrian rocks, which in the eastern part of the area are overlain by Paleozoic dolomitic limestone. Discontinuous permafrost conditions particularly presented some interesting terrain and investigation problems. The engineering geology studies included airphoto interpretation, both reconnaissance and detail geologic mapping, trenching, drilling, seismic-refraction surveys, river soundings, and ground surveys.
1971
Cumulative Sums Technique: A New Approach to Analyzing Joints in Rock. In Stability of Rock Slopes – 13th Symposium on Rock Mechanics August 30 – September 1.
Piteau, D.R., & Russell, L. (1971)
Abstract
The cumulative sums technique for analyzing joints in rock was developed as part of an extensive slope stability study of Nchanga pit. It was used successfully to determine the joint orientation trends, the pattern of their behavior and whether the joint information could be extrapolated to other areas in which slopes are proposed. This technique is illustrated with reference to the Nchanga study.
Characterizing and Extrapolating Rock Joint Properties in Engineering Practice. 20th Colloquium of Geomechanics, Salzburg, Austria.
Piteau, D.R. (1971)
1970
The effects of plan geometry on the stability of natural slopes in rock in the Kimberley area of South Africa. In Proceedings of the 2nd Congress of the International Society of Rock Mechanics, Volume 3: Paper 7-4, Belgrade, Serbia.
Piteau, D.R., & Jennings, J.E. (1970)
Abstract
Current theories of slope stability all deal with the slope as a two dimensional problem, i.e. a slice of unit length of an infinity long slope is considered for a condition of plane strain. In this the tacit assumption is made that the plan radii of the crest and toe of the slope are infinity. This is not the condition encountered in practice, particularly in open pit mining where theses radii of curvature have important effects on the safe slope angles. To determine these effects a study has been made of the slope breakback in four ‘big holes’ of the diamond mines in the Kimberly area. For each of these holes the same geological sequence is found but the thicknesses of the strata vary and the plan shapes of the four holes are also different. The slopes within the holes are up to 400 ft high and they formed naturally by breaking into the mined-out holes. These slopes have been measured and a clear relationship has been formed between plan radius of curvature of the toe of the slope and the angle of slope which has formed naturally by the breakback. These data have been analysed statistically and an empirical relationship is produced relating breakback or slope angle to the plan radius of curvature.
Geological Factors Significant to the Stability of Slopes Cut in Rock. In P.W.J. Van Rensburg (Ed.), Planning Open Pit Mines: Proceedings of the Symposium on the Theoretical Background to the Planning of Open Pit Mines with Special Reference to Slope Stability, Johannesburg, August 29-September 4, Amsterdam, Netherlands: A.A. Balkema.
Piteau, D.R. (1970)
Abstract
The study of stability of slopes in rock is basically a problem in engineering geology and assumes that the rock mass is anisotropic, heterogeneous and discontinuous in nature and that failure tends to be confined to structural discontinuities. Rational analysis of slopes in materials of such properties requires that certain geological propositions which are necessary before definition of properties of the slopes can be described, are adopted: (1) that structural discontinuities are detectable and their physical characteristics can be described quantitatively, (2) that within the whole mass it is possible to define smaller masses of similar jointing, (3) that a reliable model representing jointing of a rock mass can be constructed and (4) that the surface of failure will be plane or a combination of planes. Prerequisite to such an analysis is a qualitative and quantitative deduction of the geology, particularly of the attitude, geometry and spatial distribution of the discontinuities. Since the significant physical and mechanical properties of the mass are, for a large part, a function of the discontinuities, the basic principals on which the studies depend are therefore: (1) the systems of jointing, (2) their relationship to possible failure surfaces and (3) strength parameters of the joints. There is an additional very important factor, namely water pressures in the joints. Other factors such as mineralogy, lithology and weathering, high horizontal stresses of tectonic or other origins, natural conditions of slopes that occur in the vicinity in the same formation as the proposed slopes and effects of time on reduction of strength must also be considered.