Slope Stability Analysis of a Surface Portal: A Case Study of a Platinum Mine

DOI

10.2991/978-94-6463-900-1_65How to use a DOI?

Keywords

Slope stability analysis; slope design; geotechnical model; geotechnical domain

Abstract

The risk of portal slope collapses due to the inherent nature of semi to highly weathered soil profiles and discontinuous rock mass conditions near the surface is ever present. An optimum slope design for soil and rock formations is therefore critical to obviate major risks arising from slope collapses. This paper presents the use of a geotechnical model for portal slope stability analysis at a platinum mine. Drill core logging data was analysed using rock mass classification techniques and integrated with laboratory Uniaxial Compressive Strength (UCS) data to classify three geotechnical domains: the soft/transitional zone, moderately weathered zone and competent zone. Generated critical slip surfaces were relatively identical and isolated to the upper bench consisting of relatively weak materials. Limit Equilibrium (LE) techniques were applied for stability analysis using Slide 2D software. The Shear Strength Reduction (SSR) technique based on finite element (FE) method was employed as a verification to enable comparison of the factor of safety (FS) with the Strength Reduction Factor (SRF) values from RS2 software. A sensitivity analysis performed to assess the effects of varying slope angle with a corresponding probability of failure (PF) yielded an optimum slope angle range of 35–40⁰. The obtained FS and SRF values were above the 1.3 acceptance criterion for slope angles between 35–40⁰. The findings demonstrated that optimization of soil-rock portal slope geometries can stabilize formations thereby mitigating slope failure and the consequential hazards. Adverse joint orientation and basic friction angle were also proven to have a considerable influence on kinematically-controlled failures based on analysis done using Dips software.

Copyright

© 2025 The Author(s)

Open Access

Open Access This chapter is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/), which permits any noncommercial use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.

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TY  - CONF
AU  - Abercon Mbedzi
AU  - Shiella Mudenge
AU  - Denis Kalumba
PY  - 2025
DA  - 2025/12/07
TI  - Slope Stability Analysis of a Surface Portal: A Case Study of a Platinum Mine
BT  - Proceedings of the Rocscience International Conference 2025 (RIC 2025)
PB  - Atlantis Press
SP  - 655
EP  - 667
SN  - 2589-4943
UR  - https://doi.org/10.2991/978-94-6463-900-1_65
DO  - 10.2991/978-94-6463-900-1_65
ID  - Mbedzi2025
ER  -