Study on UAV observation methods for surface subsidence caused by multiple coal seams mining in western mining areas

In the western mining area, coal mining is characterized by shallow burial depth, thin bedrock, multi coal seam mining, and a fragile surface environment. To address the limitations of traditional observation methods for mining-induced subsidence, such as small coverage, high operation intensity, and low automation, unmanned aerial vehicle （UAV） photogrammetry technology has been introduced to observe and analyze the surface subsidence patterns of a coal mine working face. The results show that: the UAV photogrammetry method achieves a centimeter-level observation accuracy, with a median error of 4.4 cm, which meets the overall observation requirements for surface subsidence. A surface subsidence model of the entire mining area within a 2.53 km² survey area was obtained using the UAV photogrammetry method. This model accurately reflects the subsidence area and amplitude of the surface in the mining area. Due to the influence of multiple coal seams mining, the surface subsidence model exhibits an uneven basin shape. The subsidence curves along the strike and dip of the working face show asymmetry, with a maximum subsidence value of 3.18 m.