ANALYSIS OF COAL MINING OPERATIONAL SLOPE STABILITY BASED ON PT XYZ'S LIFE OF MINE (LOM) DESIGN, EAST KALIMANTAN

• Main Author: Putra Cahyadi, Reza
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/85129
• Institution: Institut Teknologi Bandung

PT XYZ is a coal mining company located in East Kalimantan. Currently, PT XYZ intends to expand its mining area to maximize reserve extraction, so a Life of Mine (LOM) design for a new pit at PT XYZ has been developed. However, the safety of the LOM design has not yet been tested from a geotechnical perspective. The slopes in the LOM design consist of low walls, high walls, side walls, and waste dumps. Five cross-sections of the LOM design were then created for slope stability analysis by first correlating the existing lithological layers with the borehole log data available around these five cross-sections. Slope stability analysis needs to be carried out by determining the Factor of Safety (FoS) both statically and dynamically, as well as the Probability of Failure (PoF) values, which comply with the minimum standards based on Ministerial Regulation of Energy and Mineral Resources No. 1827 K/30/MEM/2018. The slope stability analysis was conducted using Slide2 software, where the low wall calculations were performed using the Janbu method, and the other slope calculations were performed using the Bishop method. The material properties used for the FoS calculations were obtained from lab test data on samples taken from geotechnical drilling with a loading factor of 0.05 g. For the PoF calculations, the lab test data were first processed using the Kolmogorov-Smirnov method for normality testing. Based on the analysis results, out of the five cross-sections in the LOM design, it was concluded that one cross-section (low wall) is unsafe, while the remaining four cross-sections are safe according to the applicable regulations. Therefore, the LOM low wall section needs to be redesigned with a single slope height of 12.5 meters, a bench width of 20 meters, and a slope angle of 23°.