Strategic rock slope failure management and assessment in a highly structured brittle rock mass: a case study at Kanmantoo Copper Mine

Authors: Gale, S; Norrie, W; Lau, P Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2535_25

Cite As:
Gale, S, Norrie, W & Lau, P 2025, 'Strategic rock slope failure management and assessment in a highly structured brittle rock mass: a case study at Kanmantoo Copper Mine', in JJ Potter & J Wesseloo (eds), SSIM 2025: Fourth International Slope Stability in Mining Conference, Australian Centre for Geomechanics, Perth, https://doi.org/10.36487/ACG_repo/2535_25



Abstract:
Kanmantoo Copper Mine in South Australia faces significant rockfall hazards due to the rapid brittle and structurally controlled nature of the rockfall events. This paper presents a comprehensive rockfall management system developed onsite to address these challenges, integrating structural mapping, probabilistic assessment, physical mitigation and advanced monitoring to minimise operational disruptions. The study outlines a multiphase approach beginning with the identification of potential rockfall zones through detailed structural mapping and stability analysis using Rocscience’s RocSlope3 software. This probabilistic tool enables the identification of valid blocks to predict failure locations and the likelihood of failure by modelling all the mapped structural discontinuities and pinpointing high-risk areas for targeted intervention. Identified rockfall hazards are then mitigated by deploying rope access workers to scale loose material and install support measures, such as mesh or straps, tailored to the specific structural and geometric conditions. The system also incorporates continuous live monitoring with IDS GeoRadar’s Hydra-X slope stability radar. Strategic trigger levels have been developed and refined, based on back-analysis of previous failure events, with multiple alarm thresholds set depending on the risk and likelihood of failure. This has minimised false alarms while providing adequate warning times for personnel accessing the underground portals at the base of the open pit. Following detection, rockfall analyses using Rocscience’s RocFall2 are conducted to determine potential trajectories, run-out distances and appropriate containment measures. These findings are embedded within the site’s trigger action response plans and integrated into broader management frameworks, including the ground control management plan. This case study demonstrates how Kanmantoo Copper Mine’s adaptive, data-driven approach effectively mitigates the risks posed by rapid brittle failures using a combination of techniques.

Keywords: open pit, rockfall, structural failure

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