Obtaining Appropriate Design Parameters for Slopes in Weathered Saprolites

Authors: Fourie, AB; Haines, A Download Paper

DOI https://doi.org/10.36487/ACG_repo/708_5

Cite As:
Fourie, AB & Haines, A 2007, 'Obtaining Appropriate Design Parameters for Slopes in Weathered Saprolites', 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. 105-116, https://doi.org/10.36487/ACG_repo/708_5



Abstract:
In many open pit operations, the near-surface profile exposes weathered material. If this weathered material is shallow, or still relatively competent, it presents no major problems and conventional design approaches remain relevant. However, in some cases the weathered profile may be very deep such that the material cannot be considered as rock. A common approach in these circumstances is to use designs based on soil mechanics principles. However, some recent failures of slopes in highly weathered, saprolitic profiles have highlighted inadequacies in this approach. A case study is presented from a mine in Guinea, West Africa, where the approach was to obtain very high quality block samples from the saprolitic zone for testing in the laboratory to obtain truly undisturbed material properties and ultimately provide much improved design parameters. The pit has now been in operation for over six years and the performance of the excavated slopes in the saprolitic material validated the approach adopted.

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