Analysis of Hydrogeological Conditions and Water Prevention and Control Countermeasure for Karst Collapse Column
The 3D seismic shows that there existing four abnormal areas of suspected collapse columns in a coal mine in southwestern Shandong.Through ground drilling,the 1#and 2#abnormal areas are verified to be karst collapse columns,and the spatial morphology and development height of karst collapse columns are basically found out.The water richness of karst collapse columns is poor,and the fragmented and mixed rock blocks inside the collapse columns are re consolidated into rocks.The karst collapse columns is generally an impermeable rock stratum,and it is not ruled out that after mining,the structure will be activated,and the Ordovician limestone water will be in-troduced into the downhole along the collapse columns.To ensure safe mining,collapse columns should be left to protect the coal pillars during the mining and ecavation process.Different methods are used to calculate the safety protection coal pillars between the 3upper coal mining working face and the collapse columns.Water prevention and control measures are proposed for the mining and excavation activities in the area affected by the collapse columns to ensure safe production in the mine.