Research On Strata Behavior Regularity Of Fully Mechanized Face Under On 6 Coal Mining Goaf Of Long Wang Gou Coal Mine

Long Wang Gou coal mine is under construction, which is located at the 20 km east of ordos city, belongs to north-central of Inner Mongolia Autonomous Region. Coal mine geological structure is simple, The main minable coal is the No.6 coal seam and the inclination angle ranged from 3° to 5°.Average buried depth of the coal seam is 359 m, recoverable thickness is20 m. Above the average thickness of 1.7 m 6 coal is the overlying 6 coal seam, between two layers of coal have 4.1 m of sandy mudstone and shale. The mine plans to decorate a large mining height fully-mechanized face and a ordinary mechanized coal face. After coal mining on 6 seam, under the goaf, will decorate a special thick seam mining with large height of fully-mechanized caving on 6 seam, the fully-mechanized face mining ratio is 1:3.This paper based on the background of Long Wang Gou geological conditions, by using the method of theoretical analysis and physical simulation experiment to analysis the key strata and number above 6 seam, the key stratum instability mode and caving step distance, the secondary mining of thick coal seam mining under roof movement to pressure characteristics, law and so on. It is concluded that on 6 seam mining caving zone height of 8 m, fractured zone height of 38 m. Advance abutment pressure peak value from 11.5 to 11.5 MPa, an average of 14.7 MPa; Peak position to coal wall front 10 to 16 m, an average of 12 m, reach 20 ~ 30 m, after mining, the original rock stress significantly decreased, pressure relief effect is remarkable. 6 basic top coal caving mining face under the goaf periodic caving step distance of 12 ~ 24 m, with an average of 18.5 m. Supporting pressure peak position in front of the coal wall 4 m ~ 46 m, pressure peak intensity in 5 to 16.2 MPa, the peak impact range in 20 m ~ 50 m. Ahead of working face a crack in the process of mining production, the fracture is apparent, "three zones" development, caving to 222 m, caving zone height is 60 m, fissure zone to the surface, the surface will be sink. When the weight of the fracture of rock pillars in advance is passed on to the bracket, Support working resistance Maximum range of 35600 k N, an average of 21525 k N, increases the load coefficient 1.31 ~2.9, with an average of 1.76.Through researching the Long Wang Gou under goaf areas of large mining height on 6 seam of coal mine pressure law, understood of the stope the movement rule of overlying rock strata, face abutment pressure distribution law and defining the support working resistance of full-mechanized caving mining face, provided reasonable and scientific reference for the similar geological conditions of coal seam mining.