Technology and engineering practices on water preserved coal mining in seam with pressurized water floor

in ordet to solve the pressurized coal mining problems above pressuized aquifer of sean foor,based on Dongjiake Mine as a case,with the study on thefeatures of the aquifer( water isolated lay er) underneath Nvo. 5 seam and the fior falre depth of the mining seam.,the paper analyzed the water inrsh danger and setup the water preser ed coal mining echnology system above the pressuized water body. The resuits showed that engieng No.2 aquifers in Ordovician limestone were the main filing water souces ofNo.5 seam mnining in the mining area and the water inrush coeicient was igher than 0.06 MPa/ m regions which were taken 43%of the total area of the mining area. (2 and K3 aquifers would be the waler inrsh channels of ordovician limestone watera so could be reconstructed as a water isolated foor and would have great sigificances to the saety mining of No. 5 seam. A four in one comprehensive water preserved cal mining echmology systen with " montoring and forecasting,.advance detection.exploraton and control ombination and comprehensive prevention and control" was provided. The engineeing practices wereconducted in Chenghe Mining Area.The techmnology sysem could guide the safety producion of the mining area and could protect the 375 m water table in Oordovician system.