Study on water conductivity features of mining cracks in watery overburden strata

In order to discuss water conductivity features of a mining overburden strata above No. 15 seam in Heshun Mining Area of Qinshui Coalfield and to prevent the water inrush a ccident affected to the mine safety production, the similar material simulation method and the numerical software simulation method were applied to study the water conductivity features of themining overburden strata above the coal mining face. With the analysis on the development and distribution features of the water flow channel in the collapsed zone and the fracture zone, a summarization was conducted on the seepage law of the water in the goaf of No.3 seam. The results showed that when the coal mining face was pushed forward to 175 m, the major key layer of the overburden strata broke and the broken zone was developed to the goaf in No. 3 seam. Thus a water flow channel was provided to the water inrush from the roof. A max water flow velocity at the boundary of the water flow channel was 9.70 x 10-4 m/s. Based on the above stated as the references, a division was conducted on the water inrush danger zone of the roof above N0.15 seam and could provide the basis to the prevention of the water inrush accident occurred from the roof in Heshun Mining Area.