The drainage and decreasing pressure technology of limestone geothermal water in coal floor based on complex detective information

Depressurization by dewatering is one of the most commen methods to mitigate water hazard from aquifers under seam floor.For the characteristics of Cambrian limestone water high-pressure,groundwater high-temperature and water-rich heterogeneous distributions in 2-1 coal floor of Pingmei No.8 Mine,based on complex detective information from geological structure,confining bed,aquifer,hydro-dynamic field,hydro-temperature field,hydro-chemical temperature scale,transient electromagnetic method and DC electrical method,distribution law and geothermal water depth of Cambrian limestone aquifer are discussed and anomaly areas with rich water are delimited.Combined calculated-radius of influence in drainage and decreasing pressure of aquifer,7 wells with depth of 150 m in this aquifer are arranged in coal floor of west main roadway,the total water yield of these drainage wells amount to 300 m³/h，and the measure causes that water level of Cambrian limestone are lowered by 17.2 m during 277 days,and that atmosphere temperature also dropped 2℃ in west main roadway.50℃ geothermal water can be used comprehensively after lifting to surface.