Stability Analysis of Overburden Dump Slope of Coal/ Mineral Mines: A Review

Abstract

Open-pit mining generates vast quantities of overburden waste material, which is piled up in the form of overburden dumps. Ensuring the stability of these dump slopes is a primary concern for the open-cast mining industry. Stability analysis is employed as a technique to calculate the factor of safety for these overburden dump slopes. This analysis relies on both the geometric and geotechnical characteristics of the dump. The stability of the slope is influenced by key factors such as bench height, bench width, and the number of benches. Factors such as pore pressure, permeability, degree of saturation, moisture content, and rainfall levels can induce instability in these overburden dump slopes. The shear strength of the material constituting the slope depends on both cohesion and the internal angle of friction. Since overburden dumps are composed of a heterogeneous mix of clay, silt, and rock fragments, employing small-scale direct shear tests or triaxial shear test setups might lead to underestimated or overestimated shear strength values for the dump material. To comprehend the heterogeneity of the overburden dump material, various sieve analysis techniques are utilized. The limit equilibrium method serves as the foundational approach for slope stability analysis. Additionally, probabilistic failure analysis and numerical analysis techniques such as the shear strength reduction method offer robust tools for assessing potential failure scenarios and determining critical factors of safety.