Assessment of Mine Overburden Dump Stability Using Numerical Modelling

This work aims to analyze the appropriate dump geometry for successful mining operations and proper management of OBD material in external dumps, taking into consideration stability issues. In order to achieve this the strength properties of the OBD material were investigated through a laboratory investigation when mixed with various quantities of fly ash and Ground Granulated Blast Furnace Slag (GGBS). The FLAC/Slope software was utilized to assess the stability of external dumps containing different amounts of OBD material, fly ash, and GGBS. To determine the Factor of Safety (FOS), the dump geometry, which had an overall height of 120.0 m, was numerically simulated at various bench and slope angles. To forecast the FOS accurately, various models, including the Multiple Linear Regression Model (MLR) and the Artificial Neural Network (ANN) model, were developed. The mix proportions comprising 68% OBD material, 20% fly ash, and 12% GGBS demonstrated the highest cohesiveness value. The angle of internal friction decreased significantly with increasing concentrations of fly ash and GGBS. Through numerical modeling, it was found that for the OBD material with 10% fly ash, maximum dump capacity could be achieved with two benches at heights of 60.0 m and bench slopes of 32°. The developed MLR model and ANN model (N9) with an architecture of 6-14-14-1 predicted the FOS with excellent accuracy, with coefficient of determination values of 0.9863 and 0.9968, respectively.