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 IV On-going Projects
2nd Edition – Guidelines for Open Pit Slope Design
Objectives:The 2nd edition of the Guidelines for Open Pit Slope Design updates and expands the original 2009 publication, reflecting advances in technology, industry practice, and best practice over the past 20 years. Comprised of 13 chapters, the new edition follows the life-of-mine sequence from project commencement [Read more]
Guidelines for Heap and Dump Leach Design and Operation
Objectives: This project develops comprehensive guidelines for the design and operation of heap and dump leach facilities, addressing increasing industry concerns over catastrophic slope failures. Recent high-profile failures, including the 2024 Çöpler Gold Mine collapse in Turkey and the Eagle Gold Mine incident in Canada, [Read more]
Heap Leach Hazard Classification Whitepaper
Objectives: This project aims to develop a practical hazard screening and classification system for heap and dump leach facilities, addressing the growing concern over catastrophic slope failures in these operations. The mining industry is increasingly constructing taller, steeper, and higher-risk heaps, yet no standardized geotechnical [Read more]
Guidelines for Geotechnical Assessment and Protection of Sensitive Structures Near Open Pits
Objectives: This project aims to develop industry guidelines for the geotechnical assessment and protection of environmentally and culturally sensitive structures located near large open-pit (LOP) mining operations. The guidelines will provide standardized, practical guidance for geotechnical and mining professionals to manage risks associated with mining [Read more]
Proactive Surface Water Management Webinars
Objectives: This project aims to develop a structured series of webinars on Adaptive Water Management in Mining, addressing the critical role water plays in pit slope stability and overall mine performance. Since surface water is a primary contributor to slope failures and a key factor [Read more]
Development of Guidelines for Block Modelling
Objectives: This project aims to develop a complete geological and geotechnical dataset and workflow for constructing and evaluating a 3D block model. The dataset will include an original topographic wireframe, geology and fault wireframes, and a drillhole database. A detailed geological description will be prepared, [Read more]
Guidelines for Using Monitoring Data to Identify Slope Failure Mechanisms
Objectives: Performance-based design (PBD) has become increasingly recognized as the most effective approach for designing and operating large open-pit slopes. Under PBD, slope behavior is continuously monitored - typically through total displacement and displacement velocity - and Trigger Action Response Plans (TARPs) are activated when [Read more]
Damage-Informed Slope Design
Objectives: This project aims to improve how excavation-induced rock mass damage is understood, characterized, and quantified in open-pit mines - an essential requirement for reliable slope stability analysis. When a pit wall is excavated, the rock mass experiences strength and stiffness degradation within the Excavation [Read more]
Observational Mining
Objectives: This project addresses the growing challenge of managing deforming pit walls in mining operations. While some instabilities are anticipated during design, most are detected later through monitoring, requiring rapid and informed responses. Many sites are now adopting the Observational Mining Approach, which relies on [Read more]
LOP III Completed Projects
FAQ Compendium: Practitioner Questions and Expert Responses
Following the release of the LOP Practitioner’s Guideline webinar series on sampling and laboratory testing for open pit operations (see here and here), a significant number of questions were received from geologists, geotechnical engineers, laboratory personnel, and mine operators around the world. The webinars generated [Read more]
Tolerable Rockfall Risk and Bench Design in Open Pit Mining Operations
Objectives: This project evaluates rockfall risk and bench design in open pit mining to determine how mine operators can demonstrate that rockfall hazards have been reduced to ALARP (As Low As Reasonably Practicable). It presents four case studies that apply quantitative rockfall risk assessment methods [Read more]
Training Webinars on Weak Rock Characterisation
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]
Guideline for the Use of Geotechnical Review Boards
Objectives: Geotechnical Review Boards (GRBs) are increasingly used in major mining operations to provide independent technical assurance. However, their purpose, scope, and application vary widely across industry. In many cases, GRBs function more like audits or general design reviews, rather than focusing on high-risk geotechnical [Read more]
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
Provider: WSP Mining 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 [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]
Training Webinars on Hard Rock Characterisation
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]
Dynamic slope stability and Seismic Risk
Objectives: Earthquakes have been responsible for initiating rock slope failures on sizes varying from minor landslides limited to one or more rock blocks up to major collapse involving whole mountainsides. However, while there are intense numbers of earthquake-triggered failures in natural slopes and tailing dams, [Read more]
Transient Pore Pressures in LOPs
Objectives: In conventional stability analyses, the strength properties of the rock mass or shear strength of a rupture surface on which sliding can occur are assumed to be constant over time. Failure is then explained through the influence of a triggering event, for example a [Read more]
Open Pit and Underground Interaction
Objectives: With more and more near surface deposits being depleted by open cast mining, many companies are studying the technical economic feasibility of underground mining. This involves mines that are currently active as well as re-opening mines that were closed. Implementing mine plans that include [Read more]
Mine Closure Guideline
Objectives:Closure planning is a fundamental requirement of all existing and planned future mines. The program for open pit Closure must consider the requirements of internal and external stakeholders, local regulatory requirements, global experience, leading practice and continuous improvement. This project focuses on the need for clarity [Read more]
Horizontal Drain Hole Programs for Slope Depressurization
Provider: BGC Engineering Inc. Objectives: Horizontal drain holes (HDHs) are often an integral part of the geotechnical engineer’s toolbox when pit wall performance is affected by porewater pressures. HDHs are commonly used or proposed for open pit depressurization systems; however, data to support the design, [Read more]
Guidelines for Structural and Geological Models in LOPs
Provider: SRK Consulting Objectives: The project aim is to providing direction on how to define a 3-D structural and geological model for use in open pit studies. The guidelines include the development of 3-D structural geology models, but is also inclusive of lithological and alteration [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]
Quantifying Mining Induced Rock Mass Damage in Open Pits
Provider: Itasca Consulting Group Objectives: Open pit excavation results in disruption of the in-situ stress field with some stresses being relieved and others being increased. Damage to the rock mass behind open pit walls results from this stress redistribution and blasting practices. Damage to the rock mass from both [Read more]
LOP I 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]
Stepsim4
Objectives: There is always variability in the length, spacing and orientation of discontinuities. Hence, in practice it may be preferable to use software such as STEPSIM for a probabilistic estimate for these equivalent shear strength parameters by considering the variability of parameters such as discontinuity persistency and strength. The “step-path” [Read more]
JointStats
Provider: CSIRO & The University of Queensland (JKMRC) Objectives: The JointStats software was initially produced by the Julius Kruttschnitt Mineral Research Centre (JKMRC), University of Queensland, as part of the International Caving Study research and technology transfer program. The original software accepted standard structural data from a face mapping [Read more]
OPS/ SiroModel
Provider: CSIRO Objectives: Development of the OPS/SiroModel, as part of the original Large Open Pit Mine Slope Stability Project (LOP I), allows the user to create a model of a section of an open pit excavation for slope stability analyses. It also includes a multi-function discrete fracture network (DFN) generator. [Read more]
Slope Model
Provider: ITASCA Objectives: A completely new code called Slope Model has been written as part of the Large Open Pit (LOP) Project. The code implements a version of the Synthetic Rock Mass (SRM) approach applied to the specific case of rock slopes. SRM allows movement on joints (sliding and [Read more]