Abstract: The southwestern region of China is mainly characterized by mountainous landforms, widely distributed with high and steep slopes, and complex geological environmental conditions. In addition, with abundant mineral resources and frequent coal mining activities, large areas of goaf are formed, and slopes with multiple coal seams often suffer from collapse and sliding disasters; As a result, it causes huge loss of life and property. The article presents the Fa’er Coal Mine in Guizhou Province as case history and uses the discrete element particle numerical simulation method to study the deformation and evolution of mining slopes under the action of multiple coal seam mining. The research results indicate that after coal seam mining, the roof of the goaf begins to collapse and sink, gradually being compacted; The boundary of the goaf first generates mining induced fractures, which then expand towards the overlying rock mass. As the number of mining layers increases, the deformation intensifies, and the fractures develop towards the goaf direction of the slope, forming a potential sliding surface; The slope of the mine gradually develops into an unstable slope, leading to catastrophic geological disasters. Single coal seam mining causes less disturbance to mining slopes, while multi coal seam mining with more layers causes greater disturbance to mining slopes. Multi seam mining provides corresponding breeding conditions for the occurrence of geological disasters in mines. The deformation evolution of mines under the action of multi coal seam mining can be divided into four stages: surface transformation, collapse and subsidence, crack propagation, and critical collapse and sliding.

Key words: Multi Coal Seam Mining, Mining Induced Fractures, Mine Landslides, Deformation Evolution, Numerical Simulation