Research on Method of Water-resisting Coefficient for Distinguishing Floor Water Inrush Danger

The water-inrush coefficient is usually used as the gist on extracting water-prevention barrier when the coal seam suffered to floor water inrush. The method based on water-inrush coefficient shows some deficiencies in the process for change of mining depth, lithology and aquifer water-rich property. This paper adopts the water-resisting coefficient of the rock layer to evaluate the water-blocking performance of coal floor rock. And we use the water-resisting coefficient to appraise the danger of Ordovician limestone water invasion in the exploitation of lower 21# coal in Longgu Mine. The evaluation results are compared with the mining practice, and the method water-resisting coefficient is more rational than that of the method of water-inrush coefficient.