Study And Application On Overburden Moving Law Of Shallow Stope In Thin Bedrock

It is rich in coal resources in ERDOS area. The characters of the coal in this area are rich storage capacity, shallow bedding, small slope angle, low gas and thick coal seam, so it is called one of the 8^th biggest coal field in the world, and it it also the important base station of commercial disposable in our country. Because of its shallow bedding, thin bedrock and thick unconsolidated formation, the phenomenon of underground pressure is series strenuous in the progress of mining, at the same time, bench subsidence of roof and surface collapse are occurred, even more series accidents of water burst and sand inrush are appeared. But there were no systematic researches for the different bedrock thickness of this area, and it had being done little research on load defined. There for, it is a emergency solving problem of the fully and systematically researched on shallow overburden moving law and application.Theory study, numerical simulation and actual measurement were combined applied in this paper for the special phenomenon of underground pressure in this area. The overburden load defined and delivery rule were preliminary analyzed. The bedrock was divided into 4 classes by thickness, and the overburden moving law was studied detailed of different type bedrock. Mining technology and support design were gained by different type bedrock. And several conclusions were got in this paper, this indicated that when the static load was defined, the value was maximum by using Pu's theory, the value was minimum by using Terzaghi method, and the value was centered by using rock pillar method. When the mining range was not so large, the method of computed press using Pu's theory was feasible, but when the mining range was large, some delivery structure was formatted after roof bedrock broken, and the stress of overburden was delivered over stope through the structure. If the thickness of roof bedrock was less than 60m, the roof broken form was bench subsidence, and the surface collapse was caused by that. If the thickness of roof bedrock was less than 35m, integral vertical cutting caving of roof was occurred, and surface caving was appeared suddenly. With the increasing of the bedrock thickness, pressurized pace was increased gradually, the roof caving and surface subsidence were gentled step by step. When the thickness of roof bedrock was larger than 60m, the bench subsidence was not occurred, and the value of surface subsidence was also small. The mining technology was proper and highly active, and the support programme was feasible. The roof was controlled effectively by the support system, and achieved safety mining. Combined with the results of this paper, the first working face mining design of Su Jiahao mine was carried out in Inner Mongolia Yitai group, and underground pressure was observed in Na Linmiao NO.2 coal mine. The application results were good. The overburden moving law and application theory of shallow and thin bedrock coal seam were completed.