Sergo Ordzhonikidze Russian State Geological Prospecting University, Moscow, Russia:

V. V. Pendin, Head of Chair, Professor, Doctor of Geologo-Mineralogical Sciences
I. K. Fomenko, Professor, Doctor of Geologo-Mineralogical Sciences
D. N. Gorobtsov, Associate Professor, Candidate of Geologo-Mineralogical Sciences
M. E. Nikulina, Lecturer, Candidate of Geologo-Mineralogical Sciences, nikulinamari93@mail.ru

Instability of waste dumps is one of the problems with large ecological and economic consequences in mining. Standard calculation procedures fail to estimate stability of slopes of mining waste dumps. This article considers an integrated slope stability estimation procedure based on the comparison of the data obtained in the traditional calculation scheme (when estimated characteristics of waste properties are set within the delineated geotechnical elements); from the probabilistic analysis (when nonuniformity of waste materials is taken into account using probabilistic functions of distribution of physical and mechanical properties); and by plotting the distribution fields of waste properties. Furthermore, 3D modeling of dump slope stability was performed using the methods of limit equilibrium (Bishop, Janby and Morgenstern–Price) and finite elements. The conventional calculation of waste dump slope stability shows that the dump is stable subject to the preset design parameters according to FEM and Morgenstern–Price method and is conditionally stable by Janby and Bishop. In the meanwhile, the probabilistic analysis shows the probability of landslide (according to all methods), and the Janby methods even estimates the landslide probability as high (37 %). The implicit modeling analysis points at the invalidity of estimating mining waste as a single geotechnical element since both internal friction angle distribution and cohesion distribution fields in waste dumps show stratification. From the evidence of the analysis, under the strength characteristics obtained by static probing, the dump is stable according to FEM and Morgenstern–Price method and is unstable by Junby. Objectiveness of the results was estimated by 3D modeling of waste dump slope stability using the methods of limit equilibrium. Surprisingly, Ks calculated by Morgenstern–Price was lower in 3D variant than in 2D formulation.

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