Keynote: The art and science of ground control: examples from deep hard rock mines

Authors: Simser, B Download Paper

DOI https://doi.org/10.36487/ACG_repo/2625_0.01

Cite As:
Simser, B 2026, 'The art and science of ground control: examples from deep hard rock mines', in D Cumming-Potvin & J Wesseloo (eds), Ground Support 2026: Proceedings of the 11th International Conference on Ground Support in Mining, Australian Centre for Geomechanics, Perth, pp. 1-13, https://doi.org/10.36487/ACG_repo/2625_0.01



Abstract:
Effective ground control in the uncertain world of complex geology and deep mining is part ‘art’ and part ‘science’. A well-conceived management plan backed by observational data is required to eliminate risk to workers from hazards such as gravity failures or rockbursting. Mine design methodologies are constantly improving, as are technical advances in monitoring. This supports ground control through science, improving the understanding, measurement, and predictability of a mining environment. Data and record keeping, including photographs, are important ground control assets. This paper discusses some of the design assumptions required for ground support and gives several examples of mining tactics used to make the working environment safer. The need for ground control management plans and a rational ground support design basis is required by legislation in many mining jurisdictions and by most mining company’s corporate governance functions. There are many examples of ground support design rationale (Cai & Kaiser 2018; Kaiser & Moss 2022; Hadjigeorgiou & Potvin 2020); however, many assumptions are required before any Factors of Safety or probabilities of failure can be confidently estimated. Several rockburst and fall of ground examples occur where a high percentage of the tendons did not fail, perhaps the bolts’ plate was torn off, or the plate punched through the screen/mesh, but the bar itself did not break (Ortlepp et al. 2004 used the term ‘naked tendon’). Weak links (Simser 2007), and poor load transfer to the tendon are common problems. Mining ground support systems mix relatively stiff tendons with either brittle shotcrete and/or soft high deformation capacity mesh. There are practical challenges to match the loading stiffness of full areal coverage support to that of the tendon. This complicates the ground support design process. What capacity do you use for the tendons given field observations often show a load transfer problem? How do you add the surface support capacity? How realistic are capacity values from laboratory tests when applied to field conditions? These are examples of where empirical experience or the ‘art ‘ of ground support design come into play and require assumptions in the ground support design process. The science is advancing but still needs to catch up to the art. Rock support degradation and failure (Hadjigeorgiou 2016) is a well-known problem but not easy to quantify. Rock mass change over time and through extraction impacts the effectiveness of support systems. By design, most permanent infrastructure is placed far from the stoping areas. Stope extraction requires some excavations to be close to major stress changes, especially in deep mining. Part of the ‘art’ of ground support design is to realise when things have deteriorated beyond a practical limit, and when it is better to purge fractured ground and re-support. In deep mining, excavations experience repeated seismicity and blasting vibrations. Seismic waves are known to cause reflections/refractions that can amplify the ground motion (Yadav 2024; Alvina & Van Sint 2008) near the opening and can cause a momentary loss of confinement. Examples of using microseismic data to help understand how damaged the rock mass may be are given in the paper.

Keywords: rockburst, fall of ground, ground support, ground control, mining tactics, mine seismicity

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