Stability Analysis of Dump on Black Cotton Soil Using Overburden Filled Trench Near the Toe

The mining sector is significant for the country’s growth in terms of gross domestic product and opencast mining is playing a vital role in it compared to underground mining production. Opencast mining involves the removal of overburden and this material, which is currently a nonmarketable product, must be removed from the site for smooth mining operations. The restricted availability of space makes it necessary for the overburden to be stored judiciously to ensure the saving of ground and chances of any slide back or dangerous incidents or accidents in the future. The stability and safety of overburden dumps are of significant concern in opencast mining. The presence of a weak floor layer can be one of the several reasons for dump failure. Due to the widespread prevalence of black cotton soil in the central part of India, overburdened materials are forced to dump on this weak layer. This can be one of the reasons for dump instability. The study is conducted by collecting geomechanical properties and dump geometry of the coal mining scenario in the central part of India. The study exhibits a parametric analysis using numerical modeling to understand the effect of black cotton soil floor on dump stability and the efficacy of a trench filled with the same overburden material. Major Findings: The numerical modeling analysis in this paper was performed using the RS2 software. Through this modeling, the factor of safety derived under saturated conditions is less than that of the model under dry conditions. The dump's height and stability are increased by the method of digging a trench filled with rocks at the toe. Additionally, the same overburden material is used in place of trenches in this study, eliminating the need for extra hard rock collection and transportation.