Understanding the Bigger Picture - Interpretation of Geological Structure in Open Pit Rock Slope Stability

Authors: Oldcorn, RC; Seago, RD Download Paper

DOI https://doi.org/10.36487/ACG_repo/708_30

Cite As:
Oldcorn, RC & Seago, RD 2007, 'Understanding the Bigger Picture - Interpretation of Geological Structure in Open Pit Rock Slope Stability', in Y Potvin (ed.), Slope Stability 2007: Proceedings of the 2007 International Symposium on Rock Slope Stability in Open Pit Mining and Civil Engineering, Australian Centre for Geomechanics, Perth, pp. 449-462, https://doi.org/10.36487/ACG_repo/708_30



Abstract:
Expert assessment of geological structure can significantly improve understanding of the open pit geotechnical framework. A good structural model of the pit and surroundings is essential to understand the potential for slope instability, though commonly only the local area is generally assessed. This can lead to major features or deformation styles being missed. This paper demonstrates how structural evaluation has been used to improve the geological and geotechnical understanding of the pit slope stability issues at two very different sites. The Kumtor open pit gold mine is located in the tectonically complex Tien Shan Mountains in Kyrgyzstan. The structural geology is being reassessed, since it was proving difficult to understand styles of deformation and hence predict what potential failures could develop as the pit expanded. Careful assessment of in-pit and wider data has resulted in development of a comprehensive picture of the structural geology, from a regional to pit scale, including interpretation of the structure to be expected in the final slopes. Work is continuing to develop this interpretation, for long term mine planning purposes. Taffs Well Quarry is located within Carboniferous Limestone of the South Wales syncline. A re-evaluation of the geological structure was carried out, as a failure indicated changes in structural style not previously expected. Structural mapping identified thrust faulting associated with major folding. These faults could potentially lead to significant failures as the quarry was expanded. The model was used to predict the structural scenario in the final quarry profile and allowed geotechnical design to be more confidently carried out.

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