Research On Safety Effect Of Limestone Water On Mining Of Lower Seam Cluster In Liyan Coal Mine

The coal, in Liyan mine can be divided to three clusters as fellow: upper, middle and lower. The coals in lower cluster contains limestone belong to Ordovician System. The water inrush from limestone floor will be latent dangers when the mine develops to a deeper depth. For this, the paper is focused on the research and assessment about the safe production from the water.The key problem of mining above the artesian water is whether the floor can control the water inrush from the artesian water. Whether inrush happens is decided by the various factors and floor condition is the most important. This paper analyzed the property of the coal seam and the hydrological geology completely and in detail, investigated the main aquifer and water-resisting layer of the mine clearly, specially the limestone condition in 10down coal and Ordovician System, the connection between aquifers, condition of the fault structure and its transmissivity abilities. At the same time, investigation on the hydrogeology condition in the mines adjacent to Liyan mine. The mechanics property of each strata rock from 17 coal to Ordovician System limestone is tested by the MTS815.03 rock test system that is advanced technologically all over the world , and the parameters as compression strength, tensile strength , Young' s modulus, Poisson' s ratio, C, are obtained. Floor stress distribution in lower coal cluster after mining is simulated by software DD-FEM developed by SDUST, and the stripe failure depth on the coal seam is obtained. The research indicates that the mining above the Ordovician limestone is safe. Under the condition of normal floor, the water resisting property of the floor strata can satisfy the request of the mining under water pressure completely. At the same time, the paper also puts forward the safe technique measure and mining suggestion on the mining of the lower seam cluster.