Alemayehu Eyerusalem, Chala Endalu Tadele, Jilo Nagessa Zerihun, Tiyasha Tiyasha, Moges Belachew
Department of Geology, College of Applied and Natural Sciences, Addis Ababa Science and Technology University, Addis Ababa, Ethiopia.
Department of Mining Engineering, College of Engineering, Addis Ababa Science and Technology University, Addis Ababa, Ethiopia.
Sci Rep. 2025 Jan 10;15(1):1570. doi: 10.1038/s41598-025-86034-7.
Coal is a critical energy resource for global industries, and its extraction from open-pit mines requires effective slope stability management to ensure safe and efficient operations. This study evaluates the slope stability of the Tolay open-pit coal mine in Ethiopia, located in the Jimma zone, where geological conditions, including basalt, mudstone, and weathered soil layers, influence slope behaviour. The primary objective was to assess slope stability and recommend optimization strategies for safer mining. Geological mapping, discontinuity analysis, Schmidt hammer tests for uniaxial compressive strength (UCS), and laboratory testing of soil samples were performed to assess material properties. Stability was evaluated using Limit Equilibrium Methods (LEM) with Slide software and Finite Element Methods (FEM) using Phase2. Geological surveys revealed mudstone, siltstone, and claystone layers up to 39 m deep, with a 10 m coal seam. The results showed instability in most slope benches, with Factor of Safety (FOS) values between 0.220 and 0.430, indicating the need for reinforcement. Bench 4 showed relative stability, with FOS values of 1.228 to 1.487. Reducing the slope angle from 70° to 26° increased the FOS from 0.322 to 1.373, significantly improving stability. This study emphasizes the importance of optimizing slope geometry, particularly slope angle and bench height, to enhance mine safety and operational efficiency.
煤炭是全球工业的关键能源资源，从露天煤矿开采煤炭需要有效的边坡稳定性管理，以确保安全高效的作业。本研究评估了位于埃塞俄比亚吉马地区的托莱露天煤矿的边坡稳定性，该地区的地质条件，包括玄武岩、泥岩和风化土层，会影响边坡行为。主要目标是评估边坡稳定性并推荐更安全采矿的优化策略。进行了地质测绘、节理分析、单轴抗压强度（UCS）的施密特锤试验以及土壤样本的实验室测试，以评估材料特性。使用Slide软件的极限平衡法（LEM）和Phase2的有限元法（FEM）对稳定性进行了评估。地质调查发现了深度达39米的泥岩、粉砂岩和泥岩层，以及一个10米厚的煤层。结果表明，大多数边坡台阶存在不稳定情况，安全系数（FOS）值在0.220至0.430之间，这表明需要进行加固。4号台阶显示出相对稳定性，FOS值为1.228至1.487。将边坡角度从70°降低到26°，使FOS从0.322提高到1.373，显著提高了稳定性。本研究强调了优化边坡几何形状，特别是边坡角度和台阶高度，对于提高矿山安全性和运营效率的重要性。
