PROBABILITY OF FAILURE ANALYSIS OF HIGHWALL SLOPE DESIGN OF OPEN PIT COAL MINE PT XYZ IN EAST KALIMANTAN

• Main Author: Alfianto, Faiz
• Format: Final Project
• Language: Indonesia
• Subjects: Pertambangan dan operasi berkaitan
• Online Access: https://digilib.itb.ac.id/gdl/view/51451
• Institution: Institut Teknologi Bandung

PT XYZ is an open pit mining company located in Kutai, East Kalimantan. This research was conducted to determine the stability condition of the overall slope of the highwall based on the design of Life of Mine (LOM) PT XYZ and provide recommendations for geotechnical safe overall slope geometry by following the criteria of avalanche in accordance with The Esdm Kepmen No. 1827K/30/M3M/2018. Slope stability analysis is done by calculating the Safety Factor (FS) of LOM design slopes statically and dynamically and calculating the Probability of Failure (PoF). The Calculation of Probability of Failure (PoF) begins with the determination of distribution functions that correspond to the data possessed through the processing of goodness of Fit Test using the Kolmogorov-Smirnov and Akaike Information Criterion methods of cohesion data, deep friction angle, and content weight of slope building materials. From the result of the processing will be obtained the best distribution that generates input parameters on the Monte-Carlo method by using Slide 6.0 software. Simulation results showed that pit A highwall slopes with pore water pressure factor (Hu) 0.8 in section A-A' dynamic and Static FS values were 1.39 and 1.78 with PoF values of 0%. In section B-B, the dynamic and Static FS values are 1.55 and 1.97 with a PoF value of 0%. In section C-C' dynamic and Static FS values are 0.97 and 1.22 with a PoF value of 86%. Therefore, in section C-C' is declared unsafe from all criteria of avalanche. In section E-E' the values of Dynamic FS and Static FS are 1.69 and 2.17 with a PoF value of 0%. From the above results, given the recommendation of slope design how to hit the slope of the overall slope so that it gets dynamic and static FS values are 1.19 and 1.5 with PoF 0%. Meanwhile, by dewatering or steering assuming Hu 0.6 FS value obtained dynamic 1.12 and 1.37 with PK 0%.