Keynote Speakers

Dr Alex Campbell
Principal Engineer Mining and Rock Mechanics
Beck Engineering Pty Ltd

Abstract title: “The role of technology in the understanding of granular flow in caving mines” read abstract

The flow of caved material is complex. The cave shape, different size distributions and frictional properties for different materials combined with the mine draw strategy all impact the outcome, but are scarcely quantified in forecasts of cave performance at key stages in the planning process. Reliable tools for simulating cave flow and cave growth and technology to measure and describe cave flow and footprint deformation have only emerged in the last 10 years. This includes technology such as electronic cave markers and tracker systems, 3D laser scanning for tunnel deformation and fragmentation measurement as well as coupled DFE-CA numerical simulation.

This paper provides an overview of how the current state of knowledge has evolved to date and the knowledge gaps that still exist. A series of experiments to address these knowledge gaps have been conceptualised for future trials in operating and future caving mines. A methodology including instrumentation, monitoring requirements and operational practices is provided for each experiment.

Alex is a mining engineer with 15 years’ experience in operating mines and as a consultant. His experience spans underground and open pit mining, with roles including geotechnical engineering, mine production and long term mine planning. He holds Bachelor’s degrees in Mining Engineering and Civil Engineering, a Master’s in Mining Geomechanics and completed a PhD in 2019. Alex has special interests in sublevel caving, blasting and cave flow simulation, and has published over 20 papers. Alex is currently a principal mining and rock mechanics engineering at Beck Engineering.

Evan Jones
Principal Geotechnical Engineer
BHP

Abstract Title: “Mobile LiDAR for underground geomechanics: learnings from the teens and directions for the twenties”read abstract

The development of mobile LiDAR mapping techniques took a vast step forward during the twenty-teens, from research and development to consumer products. The promise of spatially mapping GPS-denied environments promised to open a world of unknown possibilities of which underground excavations has been just one application. The sensor technology, and hardware has improved immensely, and the future promises exciting developments. However, the acquisition of the data is only the first step in what is a whole new process and technique for underground mining geomechanics. The workflow for data acquisition to final interpretation is not an immediate, automated, and thoughtless process. Rather it currently requires a conceptual understanding of the hardware, and processing techniques and various stages to create implementable results. Currently the technology provides a valuable tool for aiding mining and geomechanical engineers with greater spatial coverage and detail for assessments of the rock mass and access to inaccessible areas. The twenty-twenty’s hold great promise for the technology.
This paper details the background to how mobile mapping technology has been introduced into underground mining geomechanics. The considerations of hardware and processing limitations is discussed with reference to case examples from the author’s experience using the technology. Finally some insights into the hardware developments and industry adoption over the coming years and into the twenty-twenty’s.

Evan was introduced to underground mining when he joined BHP Olympic Dam as a graduate in 2011. Following 12 months as an underground operator, and then a short period on the surface as a scheduling engineer, he transferred to Nickel West where he was a geomechanical engineer at the Perseverance SLC. It was during his time at Perseverance where he was first exposed to mining in challenging ground conditions including strainbursting, squeezing ground, seismicity and large-scale instabilities. Following the closure of the Perseverance Mine, he moved to Beck Engineering where he consulted on a range of underground mining projects throughout Australia, North America, South Africa, Indonesia, India and Spain. In 2014 he commenced his PhD through Curtin University, investigating methods for the recognition of large-scale instabilities in underground hardrock mines. For the past five years, his research has led to the development of methods for using mobile LiDAR scans for geomechanics applications, applying these to various mining methods and purposes. As a leader in the field of mobile LiDAR methods in underground mining he assisted Emesent as they spun out of CSIRO and commercialised the Hovermap drone autonomy platform for the underground mining industry. He has since returned to Olympic Dam as the principal geotechnical engineer where he is implementing a range of technology-based projects involving mobile LiDAR, autonomous drones and digital twins.

Dr Ewan Sellers
Research Director, Hard Rock Mining Program, CSIRO Mineral Resources
Research Leader, Mining3

Abstract Title: “Breaking new ground: challenges and opportunities for maximising value from underground blasting”read abstract

Mine to Mill Value optimisation has been extensively practiced in surface operations. The key concept of Mine to Mill optimisation is that maximum metal production by tailoring fragmentation for plant throughput delivers the optimal value from the plant though does not necessarily imply minimum cost. However, the challenges of underground mining operations have discouraged the approach. As mining moves to more remote, deeper, and highly stressed situations, the need for improved blasting techniques is magnified. Recent improvements in explosives technologies, numerical modellings, sensing, and analytics create new opportunities for the maximisation of production and minimisation of effort.

The underground mining process is examined to identify the roadblocks to complete underground Mine to Mill value optimisation. Analyses of blasting from a range of underground operations are used to quantify the current challenges. Demonstration of how the lack of sufficient and appropriate measurement of important properties such as blastability, in situ structures, hole deviation, and fragmentation aligned with the limited insights into the effect of mining-induced stresses show how current approaches can often lead to overbreak, dilution, production delays, the lack of excavation stability, and poor plant performance. Environmental and safety hazards combined with production delays are created by nitrate and diesel emissions.

Recent advances are reviewed and compiled to present the opportunities that are easiest to accomplish and others that will take longer to apply in practical operations. The paper then explores the possibilities based on current research and prototype implementation. On the horizon, there are a suite of new technologies such as wireless detonators, nitrate-free explosives, robotic operations, and cognitive spatial management that will enable a new generation of mining methods. These include in-place operations and in-mine recovery where the material movement and the environmental footprint of mining operations being reduced whilst extraction is optimised, and productivity and excavation stability increased.

Dr Ewan Sellers is research director for Hard Rock Mining within CSIRO Minerals and the Research Leader with the Mining3 Collaborative Research Partnership. He has a PhD in Geomechanics from the University of Cape Town, and is a specialist in rock mechanics with broad experience in numerical modelling, instrumentation, seismology, blasting and mine to mill optimisations. He has worked in the mining industry for over 30 years on hundreds of mining projects across the world. He started as a mining researcher at CSIR improving geotechnical stability in South African deep level mines. Ewan was group manager for mining optimisation at AEL explosives manufacturer in South Africa and worked as a consultant at JKTech creating improvements across the value chain in several mining companies. Ewan represents CSIRO on the ACG Board of Management.

 

 

Dr Jonny Sjöberg
General Manager, Principal Engineer
Itasca Consultants AB, Sweden
Adjunct Professor in in Rock Mechanics and Rock Engineering, Luleå University of Technology, Sweden

Abstract title: “Solving rock mechanics issues through modelling: then, now and in the future” read abstract

There is no dispute about the advances in numerical rock mechanical modelling following its debut in engineering science some 50 years ago. Significant strides have been made since the days of punch cards and line printers, with modelling tools now being easy to use (well, relatively speaking) and capable of replicating many (but not all) aspects of rock behaviour. This paper explores some common rock mechanical problems in underground mining, and how these have been addressed through numerical modelling. The described issues include ground support design, caving prediction, large/squeezing deformations, mining-induced ground subsidence, mining seismicity, and more. Examples of how modelling technology has evolved over the years are given, while also pointing out current gaps and limitations in the technology. Finally, an outlook for the future is presented, including some of the challenges that we are facing. An increased fundamental understanding of many rock mechanics issues is still required, but eventually, one may envision a deep integration of rock mechanical modelling into mine planning and production, for a more sustainable future mining.

Jonny Sjöberg is a rock mechanics engineer with experience in operations, research, and consulting. He has worked for several mining and consulting companies on projects dealing with underground and surface mining rock mechanics, civil engineering tunnelling, and rock stress measurements. Currently, he is the general manager of the Itasca office in Sweden. He is also appointed adjunct professor in rock mechanics and rock engineering at the Luleå University of Technology.

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