Steep End-Slope Mining and Slope Stability of Extremely Thick Inclined Coal Seam Open-Pit Mine

Considering the characteristics of extremely thick inclined open-pit coal mine with large amount under end slope, large end-slope height, and long exposure time, it is important to study the slope stability research during open-pit mining. This study takes the whole process of excavation descending and steep end-slope mining of an extremely thick inclined open-pit mine as the background. The slope stability factor of the end slopes were calculated for each stage of mining with different coal seam thicknesses by using the strength reduction method. The slope data, such as vertical stress, horizontal stress, and increment of maximum shear strain, are analyzed. The results show that the vertical stress and stability factor are decreasing throughout the mining stage. The horizontal stress shows a pattern of increasing and then decreasing in the excavation descending and steep end-slope mining. The greater the thickness of coal seam, the less the stability of the slope.