The Burnt Rock Feature And Retain Waterproof Coal Pillar At Yangchangwan Coal Mine Of Ningxia Province

China is a large country which teems with coal and is rich in coal reserves which is mostly distributed in the north. Ningxia is located in the northwest, the sun exposure is extremely high and the precipitation is low which lead to an arid and semi-arid climate. Its coal has characteristics such as thick seam and buries shallow and so on. The spontaneous combustion of coal seam which is burning and burnt distributed widely due to easy self-ignition coal seam and general spontaneous combustion phenomenon. The burnt rock is a kind of metamorphic rocks which developed in baking metamorphic country rock by the reason of spontaneous combustion of thick coal seam. Its strength reduces and water storage easily because of the developmental fissure. Their existence has a certain influence on the safety in production of coal mine, so study of the burnt rock and its aquifer characteristics are of certain significance to coal mining and design, and also have certain reference value for coal mining in the burnt rock area of the northwest.Yangchangwan, a modern oversize coal mine, is located in Ningdong Town, Lingwu City, and annual production is huge. There are three discontinuous burnt areas which are named No.Ⅲ, Ⅳ, V at this coal mine. Fracture is developed in burnt rocks, and the aquifer of burnt rocks is rich. No.Ⅲ, Ⅳ burnt areas are near the mining boundary, so there is a certain impact on coal’s mining and it’s necessary to make sure the depth, extent and water content of burnt rocks before mining.In this paper, No.Ⅲ, Ⅳ burnt areas as the research object. Through the method of magnetic、natural potential and drilling determine the range of the burnt area and position and extent of the coal combustion, meanwhile, describe the burnt rocks and calculate the height of the baked rocks and burnt rocks. The aquifer of burnt rocks is a rich aquifer which parameter determined by the pumping test and a right way. In the process of mining, retain the waterproof coal pillar and avoid the water bursting accident, ensuring safety production.Through analysis, compare and calculate, in this paper, the range of burnt areas, the mine seam combustion and the height of burnt rocks and baked rocks are determined accurately. At the seam time, the lithology of burnt rocks in No.Ⅲ, Ⅳ burnt area is described. In addition, the water level, drawdown, specific capacity and static reserves of the aquifer of No.Ⅲ, Ⅳburnt area are calculated. On the basis of the roof and floor feature of N0.2mine seam and Prevention and control of coal mine water regulations and Coal-mining Regulations under Three Circumstances, retain waterproof coal pillar in No.Ⅲ, Ⅳburnt area, after calculation, leave86.39-94.39meters an coal pillar.