DETERMINING THE DESIGN RECCOMENDATIONS OF HIGHWALL AND LOWWALL SLOPE OF COAL MINE PT. XYZ IN TAPIN, SOUTH KALIMANTAN

• Main Author: Mahdi Patriansyah, Muhammad
• Format: Final Project
• Language: Indonesia
• Subjects: Pertambangan dan operasi berkaitan
• Online Access: https://digilib.itb.ac.id/gdl/view/51492
• Institution: Institut Teknologi Bandung

PT. XYZ is a coal mining company located in Tapin Regency, South Kalimantan. The company plans to mine 2 pits. Before carrying out mining, the company needs to conduct a study on work safety and security as the main requirements for carrying out mining, one of them is slope stability analysis. Therefore, this study aims to determine the stability of the final design of PT. XYZ coal pit slopes by considering the Safety Factor (SF) and the Probability of Failure (POF). This study requires data consist of content weight, cohesion, and internal friction angle based on laboratory tests. The data was then performed for Goodness of fit test to select the best distribution function using the Kolmogorov-Smirnov method followed by the Akaike Information Criterion Test. The outputs are mean, standard deviation, maximum and minimum relative which are being the input parameters for the Monte-Carlo simulation method using Slide 6.0. The calculation of the safety factor for the Highwall slope was analyzed using the Bishop method, while the calculation of the safety factor for the Lowwall slope was analyzed using the Janbu method. The slope stability analysis used the slide probability analysis to process the data. The slope stability analysis used the Ministerial Decree No. 1827 K / 30 / MEM / 2018 as a reference for determining the slopes is safe or not. The results of the slide probability analysis carried out using some of softwares such as Microsoft Excel, Matlab 2019, @Risk 7.6 & 8.0, and Slide 6.0 are unsafe for Highwall slopes at sections 1 and 3. Therefore, it requires geometric redesign and good flow water management around these slopes. The results of the recommendations for slope design in section 1 have SF in static conditions are 1,35 (Highwall) & 3,32 (Lowwall) and dynamic are 1,10 (Highwall) & 2,35 (Lowwall) with all POF values 0-0.4%. Meanwhile, for section 3 SF obtained in static conditions are 1.39 (Highwall) & 1.85 (Lowwall) and dynamic are 1.15 (Highwall) & 1.45 (Lowwall) with all POF values 0%. Based on these results, the draft recommendation desaign was accepted according to the slope stability criteria of the Ministerial Decree No. 1827 K / 30 / MEM / 2018 with Static SF> 1.3, Dynamic SF> 1.1, and POF <5%.