Research into ascending mining feasibility of guotun mine close distance coal seam

In order to study the upward mining problem under different layer distance on the No.3upper coal seam above the area that had been mined of the No.3lower coal seam of Guotun coal mine first mining area,based on the coal seam conditions and mining situation,obtained the height of caving zone and fractured zone through empirical formula,then simulated and analysed No.3upper coal seam deformation and failure characteristics after mining No.3lower coal seam.the results show that,when distance is more than 15 m,the lower mining has little effect on No.3upper coal seam;when distance is about 10～15m,No.3upper coal seam is damaged seriously,only partially recoverable;when distance under 10 m,the integrity and continuity of No.3upper coal seam has been seriously undermine,and the occurrence of greater value level dislocation,and can not be upward mining.Through "two zones"field measurement,obtained the collapse production and crack-production ratio,is respectively 5.65 and 16.52 that similar with the theoretical analysis and numerical simulation results,further demonstrate the upward mining feasibility of 3up coal seam.