SLOPE STABILITY ANALYSIS ON THE DESIGN OF LIFE OF MINE (LOM) PT ABC’S OPEN PIT COAL MINE IN SOUTH BORNEO

• Main Author: Bagus Kurniawan, Fajar
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/57521
• Institution: Institut Teknologi Bandung

PT ABC is a mining company engaged in coal mining in South Borneo. PT ABC conducts coal mining using the open pit mining method and it is currently determining the Life of Mine (LOM) design which consists of High Wall and Low Wall slopes. The three vertical sections of the LOM design are then used for slope stability analysis by first correlating the existing lithological layers in the pit with drill log data around the three sections. Based on the Decree of the Minister of Energy and Mineral Resources No. 1827 K/30/MEM/2018, slope stability analysis needs to be carried out by determining the value of the Safety Factor (SF) in static, dynamic conditions, accompanied by a Probability of Failure analysis (PoF). Slope stability analysis was carried out using software, namely Slide 6.0 where the Low Wall was calculated using the simplified Janbu method for each slip plane, and on the High Wall, the simplified Bishop method was calculated for the circular failure type. Calculation of static and dynamic Safety Factors was carried out using laboratory test data on samples obtained from geotechnical boreholes where in dynamic analysis a seismic loading factor of 0.03g was added. For the calculation of the Probability of Failure, the data from the lab test results were taken out of statistical parameters including the type of distribution using the Goodness of Fit Test consisting of the Kolmogorov-Smirnov statistical test and the Akaike Information Criterion (AIC). Groundwater conditions are assumed to follow the contours of the slopes with a Hu factor value of 0.6. From the results of the analysis, the LOM design of the three sections was concluded to be unsafe based on existing regulations because static FK < 1.3; Dynamic FK < 1.1; and PK < 5%, so it is necessary to redesign the LOM design for the Low Wall section with a single slope height of 30 meters and a slope of 30-48° with a berm width adjusting the slip plane, while for High Wall the overall angle is based on 30°.