Conference chair

Johan Wesseloo

Associate Professor Johan Wesseloo
Principal Research Fellow — Rock Engineering
Project Leader — mXrap Development
Australian Centre for Geomechanics

Johan has been involved in geotechnical engineering since 1998, with experience in both underground and open pit environments. Johan obtained a BEng (Civil), MEng and PhD (Geotechnical) from The University of Pretoria, South Africa and is Fellow of the Southern African Institute of Mining and Metallurgy. He started his career as a geotechnical engineer with SRK Consulting, South Africa. In 2007, Johan joined the Australian Centre for Geomechanics, where he led and completed the ACG’s High Resolution Seismic Monitoring in Open Pit Mines project and the Mine Seismicity and Rockburst Risk Management. Johan has an interest in the rock engineering aspects of mine-induced seismicity and developed several procedures and methods for seismic analysis for rock engineering purposes and mining seismic hazard assessment methods, which are integrated into mXrap Apps.

Keynote speakers


Dr Bruce Brown
Bruce Brown Consulting Pty Ltd, Australia

Bruce Brown has 43 years’ experience in geotechnical engineering and mine waste management. His career has comprised 25 years as a principal of the international consulting group, Knight Piésold Consulting and 13 years as the Chief Adviser, Tailings and Dams for Rio Tinto, Technology and Innovation. In this time he has been responsible for the design, construction, operation and closure of numerous tailings storage facilities in North and South America, Africa, Europe, Asia, Australia and the South Pacific. His experience ranges from cold regions of Alaska and Northern Canada to the mountainous regions of South America and the tropical monsoonal countries. With Rio Tinto, he has been focussed on risk management, technical reviews and development of standards for effective mine waste management. He was an author of the ANCOLD Guidelines on Planning, Design, Construction, Operation and Closure of Tailings Dams and the Federal EPA Tailings Containment module of the Best Practice Environmental Management in Mining.
Dr Brown is now in private practice and offers services to the mining and consulting communities for peer and independent technical and strategic reviews, audits for operations and construction quality assurance, risk assessments, conceptual design and value engineering.

Keynote address: What are the real risks for tailings facilities?

Read abstract
The movement towards risk based design and operation of Tailings Storage Facilities (TSFs) has taken place over the last few decades. The establishment of the consequence of failure of a facility is used to determine the design criteria to be used in its design. These criteria generally set the acceptable return periods for seismic and hydrologic events that the facility must accommodate. In addition, there are generally several levels of risk assessment carried out of the design to highlight technical risks that require particular attention and controls to manage. These are usually addressed in the design phase of project development.

Despite this focus on technical risk assessment at the design phases of the development of a TSF, there are still a significant number of failures occurring in every year. In recent times, there have been a number of high profile TSF failures in facilities owned by major mining houses and/or located in highly regulated, first world countries. In almost every case, the investigation into the failures have been carried out by high profile, internationally recognized geotechnical engineers who have identified the technical reasons for the failure.
In many cases, it has been shown that the root causes of the failures have been a failure in governance, capital constraints, change management, independent reviews, construction supervision, operation etc. The investigation of failures and reported to the public are almost exclusively focused on the technical cause with much less on what is often the underlying root cause.

A number of international mining industry groups have recognised the lack of effective governance as being a major risk that could lead to TSF failures. The Mining Association of Canada (MAC) and the International Council on Mining and Metals (ICMM) are two examples.
In this paper, the various methods for risk assessment and management are described. Non-technical risks that arise in the design and operation of TSFs are discussed and importance of good governance and continuity of its application during the full life cycle of the facilities is emphasised.

Dr German Flores-Gonzalez
Newcrest Mining Limited, Australia

German is a mining engineer with more than 35 years of experience in geotechnical engineering, mining engineering, mine planning and operations of block/panel caving and large open pits mines and projects. He has performed various roles during his professional career including mine preparation and production shift supervisor, geotechnical engineer and geotechnical engineering superintendent for block/panel caving and open pits mines, study manager for the transition from open pit to underground panel cave mining, study manager for large open pit and panel caving projects, group development manager for block/panel caving and open pit projects and corporate roles as head of development and head of mining. He was the project manager for Chuquicamata Underground project. Currently is the general manager caving at Newcrest Mining Limited.

Keynote address: Major hazards associated with cave mining – are they manageable?

Read abstract
Cave mining methods have become viable and preferred mass mining options where the objectives are low cost and high production rates. However, the cave mining industry has already entered into a less certain period where current cave mining methods may not be suitable to achieve the low cost and high productivity objectives. This environment includes deeper and sometimes blind deposits (more than 1,200m from surface), lower average grade deposits, harder and heterogeneous rock masses, higher stress and in some cases higher temperature environments. This scenario is requiring greater caving block heights, demanding for increased safety and productivity and escalating mining costs (capital and operating). In addition, there is increasing shortage of technical skills, becoming more difficult to access capital and communities are after higher environmental standards. In this new cave mining environment, several challenges or risks are identified that can have critical impact on safety, productivity and profitability. It is necessary, therefore, that these major hazards be acknowledged, and the likelihood of their occurrence be evaluated and minimised during the deposit investigation, mine design and planning, and operational stages of caving process. These are not trivial issues and can have the most serious of consequences. They demand serious managerial and technical attention.
This paper focusses on the major risks of caving process which includes cave establishment (development, drawbell opening, undercutting), cave propagation, cave breakthrough to surface, steady state production and the end of the mine life. Measures to manage these risks aiming to reduce their consequences are also discussed.

John Hadjigeorgiou

Professor John Hadjigeorgiou
University of Toronto, Canada

Professor Hadjigeorgiou holds the Pierre Lassonde Chair in Mining Engineering at the University of Toronto. John previously served as head of the Department of Mining, Metallurgical and Materials Engineering at Université Laval in Quebec City.

Dr Hadjigeorgiou is a PEng with over 25 years of international experience in mining engineering. John is a past recipient of the John Franklin Award from the Canadian Geotechnical Society and the Rock Mechanics Award from the Canadian Institute of Mining. John is a fellow of the Canadian Institute of Mining and Metallurgy and holds the ICD.D designation from the Institute of Corporate Directors.

Keynote address: Understanding, managing, and communicating geomechanical mining risk

John Lupo

Dr John Lupo
Newmont USA Limited, USA

Dr Lupo holds a PhD in geotechnical engineering. He has over 30 years’ experience working within the mining industry. He currently is the Senior Director of Geotechnical and Hydrology at Newmont Mining Corporation in Denver, Colorado, USA.

Keynote address: Geotechnical risk-informed decision-making in mining


Geoffrey Potgieter
Mount Isa Mines Limited, A Glencore Company, Australia

Geoffrey began his career in 1994 as a Learner Official at President Steyn Gold Mine in South Africa. He received his Chamber of Mines Certificate in Rock Engineering in 2006 while working as a Rock Mechanics Officer at Rustenburg Platinum Mine gaining extensive experience in hard rock narrow tabular mining. He has gained experience in Board and Pillar mining and Sub Level Open Stoping while working as Senior Rock Mechanics Engineer at Xstrata Alloys and Rock Mechanics Superintendent at Mount Isa Mines Copper Operations. Geoffrey represented Africa on the ISRM Young Members Presidential Group and served on the national committee of the South African National Institute of Rock Engineering.

Keynote address: Risk-based access control at Mount Isa Copper Operations

Read abstract
Mount Isa Copper Operations (MICO) is one of the oldest and deepest mines in Australia, comprising the largest underground network of mine development in the world. During the early operational years, ground support, particularly surface support, was not routinely installed. Although rehabilitation in recent years has drastically reduced the amount of tunnel without support, there remain tens of kilometres of excavation with limited to no ground support installed. In addition, older development was often mined within close proximity to unfilled or partially filled stopes and vertical openings. The voids pre-date modern 3D mine plans and scanning technology, furthermore access to the voids to conduct scans is limited, this results in an imperfect understanding of the void sizes and proximity to accessible drives. The lack of ground support and knowledge of void status poses significant ground failure risks at MICO.

A significant increase in rock related near-hit incidents occurred during the second half of 2014 and the first half of 2015. A number of these incidents had the potential to cause severe or fatal harm. The incidents triggered internal investigations that aimed at understanding and reducing the ground failure risk. The outcome of the investigations was the creation of a series of interlinked systems namely the Tunnel Condition Risk Assessment (TCRA), Mine Closure Areas (MCA), Ground Awareness Training (GAT), Vertical Opening Pillar Hazard Assessment and Control (VOPHAC), Stope Void Review (SVR), Manual Scaling crews, Fall of Ground Database and the QA/QC Management Plan (QA/QC MP). The Individual components of the system are specialised and simple, however; the system is comprehensive and robust. Each of the components as well as how they interlink is discussed within this paper.

The interlinked systems and practices provide controls and have proven to be effective at reducing the ground failure risks. Although the systems were developed at MICO, they have the potential to be easily adapted and utilised at other mine sites.

Event Contacts

Josephine Ruddle
Event Manager, Australian Centre for Geomechanics 

Candice McLennan
Event Coordinator, Australian Centre for Geomechanics