The end goal in open pit mining is to achieve reliable mine slopes that, if they fail, do not cause loss of life, equipment damage, sustained losses of production, or the inability to achieve published reserves. Over the years these requirements have been hampered by critical gaps in our knowledge and understanding of the relationships between the strength and deformability of jointed rock masses and the likely mechanisms of failure, with divided opinions on how to characterise the rock mass. Commonly, there has been an uncritical derivation of physical rock properties from empirical classification systems and an equally uncritical use of such physical properties in design analyses without a clear understanding of the geological framework. These inadequacies have been exposed by a number of spectacular large open pit slope failures, resulting in multiple fatalities, production losses, and unfavourable worldwide publicity. Collectively, they have demonstrated a need to step outside the box and reassess the fundamentals of rock mass strength and slope failure mechanisms from first principles.
The LOP Project slope design research tasks have been and continue to be directed at addressing these inadequacies by enabling the effective use of geological and geotechnical data in assessing rock mass characteristics, 3D modelling, and simulation of slope failure mechanisms, design analysis, and uncertainty analysis. The research tasks performed by the LOP project since 2009 have been drawn on the experience of the sponsors and a number of industry consultants and practitioners who have shared their knowledge and experience by contributing to several of the sections in the LOP Guidelines and Research Projects below.
Project Providers
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LOP Completed Projects
Seismic Risk and Open Pit Slopes
Objectives: The potential effects of earthquakes on the stability of open pit mines were addressed in this research work, also incorporated in Chapter 10 of the design guidelines book. The outcome of this study concluded that: Topographic effects are important reasons why pit slopes are more stable than natural slopes. [Read more]
Stress and Open Pits
Objectives: All rock masses are subjected to in situ stresses resulting from the weight of the overlying strata and from locked in stresses of tectonic origin. The excavation of an open pit results in disruption of the existing stress field with some of the stresses being relieved, while others [Read more]
The Effect of Water Pressures on the Stability of Closely Jointed Rock
Provider: ITASCAObjectives:The objective of this research work was to establish a numerical modeling approach to compute the distribution of water pressures in a pit slope in low permeability fractured rocks, and the response of water pressure with time to mining.The failure of a slope necessitates one or more of the [Read more]
Synthetic Rock Mass (SRM)
Provider: ITASCA Objectives: The main focus of early years of the original LOP Project (2005 to 2014) was on preparation of the book Guidelines for Open Pit Slope Design and delivery of research tasks that included Siromodel (also known as the OPS or Open Pit Simulator software), JointStats, Stepsim4, and the development [Read more]
LOP II Completed Projects
Data Uncertainty
Provider: Golder Objectives: The purpose of the Data Uncertainty project is to improve on the guidelines for data confidence, specifically to build and improve on the guidelines presented in Chapter 8 of Guidelines for Open Pit Slope Design. The table “Target Levels of Data Confidence” in Chapter 8 of [Read more]
Slope Monitoring Guidelines
Objectives: Although most mining companies have in-house systems in place for slope monitoring, experience indicates that mining operations continue to be surprised by the occurrence of negative geotechnical events. Site engineers want and need help in the selection and design of performance monitoring systems. They also want guidance that [Read more]
Effective Stress In Large Open Pit Slopes
Provider: Piteau Associates UK Limited Objectives: Understanding groundwater flow, pore pressures and effective stress in pit slopes is vital for the delivery of economic and safe slope designs. Pore pressure is one variable controlling slope stability which can be measured, simulated, predicted and, through pro-active intervention, effectively managed to [Read more]
Integration of Laser, Radar And Total Station With 3D Kinematic Analysis
Provider: Geoapp s.r.l. Objectives: Nowadays most large open pit mines have sophisticated systems in place for near real-time slope monitoring. Despite the availability of massive datasets of monitoring data, negative events associated with slope failures, having in some cases strong impact on mine safety and productivity, are still occurring [Read more]
LOP III On-going Projects
Evaluating Large-Scale Pit Slope Stability Methods
Objectives: In September 2022, the Large Open Pit research project (LOP) initiated a review of large-scale pit slope stability methods. The project was triggered in part by the evolving needs of the industry and in part by a conference publication and a keynote address by [Read more]
Validation and Stress-testing of the proposed Design Acceptance Criteria
Objectives: This research aims to provide an evaluation of the consistency of the fundamental assumptions behind a newly proposed DAC matrix (within LOP II) against acceptability criteria adopted more broadly in open pit mining. It is postulated that risk tolerance, measured as the likelihood of [Read more]
A Combined DFN-LE Approach to Improve Inter-Ramp Design
Objectives: The fundamental technology applied to Inter-ramp analysis for slope design and optimization has not changed significantly over the past decade or two, yet it remains the component of open pit slope performance in which uncertainty is most evident. A number of existing methods are [Read more]
Combining Structural and Monitoring Data in Open Pit Mines
Objectives: The aim of the proposal is the extension “Integration of laser, radar and total station with 3D kinematic analysis to support the interpretation of the mechanism of structurally controlled failures” funded in the framework of LOPII, to support the development of a specific software [Read more]
LOP Education and Training Mandate
Objectives: The Large Open Pit (LOP) project is an international research and technology transfer project focused on the engineering of large slopes associated with open pit mines. It is an industry-sponsored and funded project that was initiated in 2005. Among the initiatives mandated by the [Read more]
Coupled Hydro Mechanical Behaviour and Effective Stress
Objectives: Effective stress is fundamental component of open pit rock slope design because it controls shear strength and deformation. The geotechnical processes of pit slope deformation and behaviour can only be fully understood by considering the interaction between hydraulic and mechanical processes in geomaterials through [Read more]