Mining Scheme and Slope Stability Analysis of the First Mining Area of an Open-Pit Mine

Reasonable mining procedures are very important for energy saving in open-pit mines. However, studies on mining procedures in the first mining area of large open-pit mines characterized by thick and inclined coal seams are limited. The Hongshaquan open-pit mine located in Xinjiang, China was used as an example in this study to relieve space strain of soil drainage and reduce stripping weighted transport distance of the mining scheme in the first mining area of large open-pit mines characterized by thick and inclined coal seams. Three mining schemes, including eastward fan-shaped, southward partial gentle, and southward overall gentle turning schemes, were put forward. Stripping ratio, coal mining, stripping distance, and lifting height of the three schemes were compared and analyzed while considering technical and economic indicators. Accordingly, the stability of typical slopes in the stope and inner and outer dumps of the open-pit mine under the optimal mining scheme was analyzed using numerical simulation. Results demonstrate that stripping ratios of the three schemes are stable below 4 cubic metres per ton. The eastward fan-shaped turning scheme presents the minimum stripping distance, stripping lifting height, and mining distance, while the southward overall gentle turning scheme shows the minimum lifting height. The eastward fan-shaped turning scheme demonstrates enhanced short-term economic benefits, while the southward overall gentle turning scheme exhibits improved long-term economic benefits. The southward overall gentle turning scheme combined with the future expansion demand of the Hongshaquan open-pit mine, difficulty in the mining process, upgrading of mining technology, and other factors was adopted to mine the first mining area. Slope stability coefficients of the stope and inner and outer dumps meet the safety reserve coefficient and safety production requirements under this scheme. This study can provide a reference for the comparison and selection of mining procedures and slope stability analysis of similar open-pit coal mines. © 2022. School of Science, IHU. All rights reserved.