Castro, S & Huaman, C 2020, 'Influence of the hydrothermal alteration rocks on the stability of an open pit
mine of the south of Peru: a case study', in PM Dight (ed.), Slope Stability 2020: Proceedings of the 2020 International Symposium on Slope Stability in Open Pit Mining and Civil Engineering
, Australian Centre for Geomechanics, Perth, pp. 367-382, https://doi.org/10.36487/ACG_repo/2025_20
Hydrothermal solutions considerably modify the physical and mechanical properties of rocks, and consequently have an impact on the pit slope stability; however, this effect is sometimes not sufficiently considered in an open pit slope design and the geotechnical model is only based on lithology. This could cause during mining, variable and poor rock mass qualities to be observed with respect to those assumed in the design. This generates the need for redesign of the pit slopes based on additional geotechnical investigations such as surface mapping on the existing benches, to develop or update the geotechnical model based on hydrothermal alterationand then carry out the slope stability analysis (Factor of Safety and displacements). The case study presented in this paper shows that the zonation in terms of hydrothermal alteration types is required when there is a strong influence of this phenomenon, but also needs to be accompanied by a zonation based on variability of rock strength in each alteration type, since the effect can be very intense up to transform the rock in residual soil.
Keywords: hydrothermal alteration, open pit, weak rocks, residual soils
Bieniawski, Z 1989, Engineering Rock Mass Classification, John Wiley & Sons, New Jersey.
Deere, DU & Patton, F 1971, ‘Slope stability in residual soils’, Proceedings of the Panamerican Conference on Soil Mechanics and Engineering Foundation, Puerto Rico.
Deere, DU, Hendron, AJ, Patton, F & Cording, EJ 1967, ‘Design of surface and near surface excavations in rock’, in C Fairhurst (ed.), Proceedings of the 8th US Symposium on Rock Mechanics:Failure and Breakage of Rock, American Institute of Mining, Metallurgical, and Petroleum Engineers, New York, pp. 237–302.
Hexagon Mining 2018, MinePlanTM 3D, version 15.6, computer software, Hexagon Mining, Tucson.
Hoek, E, Carranza-Torres, CT & Corkum, B 2002, ‘Hoek-Brown Failure Criterion - 2002 Edition’, Proceedings of the North American Rock Mechanics Society Meeting, Toronto.
Hoek, E, Carter, TG & Diederichs, MS 2013, ‘Quantification of the Geological Strength Index chart’, Proceedings of the 47th US Rock Mechanics/Geomechanics Symposium, American Society for Rock Mechanics, Alexandria.
Hoek, E, Kaiser, PK & Bawden, WF 1995, Support of Underground Excavations in Hard Rock, Rotterdam, A.A. Balkema.
Marinos, P & Hoek, E 2000, ‘GSI: A geologically friendly tool for rockmass strength estimation’, Proceedings of the International Conference on Geotechnical and Geological Engineering, GeoEng2000, International Society for Rock Mechanics,
Read, J & Stacey, P 2009, Guidelines for Open Pit Slope Design, CRC Press/A.A. Balkema.
Rocscience 2018, Slide version 2018, computer software, Rocscience Inc., Toronto.
Rocscience 2019, RS2, computer software, Rocscience Inc., Toronto.
United States Army Corps of Engineers 2003, Slope Stability, Engineering Manual, EM 1110-2-1902.