Characteristics and causal mechanism analysis of geological hazards induced by underground mining in the longtan formation coal mine group in Guizhou: A case study of AH coal mine geological disasters

For a long time, experts and scholars engaged in the analysis of the causes of mine geological disasters have primarily studied two aspects: natural factors and human factors. Natural factors refer to natural causes such as topography, geological structures, karst processes, rainfall, weathering, and plant root splitting. Human factors refer to human activities such as mining. However, the main and secondary causes of geological disasters triggered by these factors have not been thoroughly investigated. This paper takes AH coal mine as an example and, through field investigations, engineering surveys, and comprehensive analysis, summarizes the characteristics of geological disasters induced by the mining of the Longtan Formation coal mines in Guizhou. The main geological disasters observed include ground subsidence and collapse. The subsidence pits are all developed in the Quaternary system and are of small-scale. Collapses (hazardous rock masses) are developed in the Changxing Formation limestone, characterized by well-developed rock cavities, and controlled by steeply inclined fractures. They are classified as medium-sized hazardous rock masses based on volume and as intermediate hazardous rock masses based on relative elevation. Using theoretical calculations and graphical methods, a quantitative analysis is conducted from two dimensions: the safe depth of coal mining and the range of influence of goaf (the area left behind after coal extraction). The research indicates that the formation of ground subsidence within the coal mine area is primarily caused by underground coal mining while the perilous situation of rockfall masses is mainly induced by underground coal mining, with natural conditions playing a secondary role. This study contributes to the improvement of theoretical analysis of the causes of similar mining geological hazards and provides theoretical guidance for the prevention andcontrol of similar mine geological disasters.