Study On The Structural Charicteristics Of Overlying Strata And Its Influence On Mining Of Lao Hutai Mine

The main mining coal seam of Lao Hutai Mine is the extra thick coal seam on Laohutai mine.After the slicing and filling,now the section coal pillar,set by the water and sand filling mining,are mined by the technology of fully-mechanized caving mining,or by the technology to top coal caving mining of extra thick coal seam.The structural damage and the fault activity of overlying strata is very complicated,caused by repeated mining in extra thick coal seam and has great difference with conventional mining.Therefore,it is necessary to study the structure characteristics of the overlying strata in the Lao Hutai Mine.The movement and failure process of overlying strata,overlying multi-strata spatial structure and its motion law under mining conditions,and characteristics of overlying strata in the typical tectonic area,and the distribution law of "three zones" of overlying strata in the repeated mining face are determined,optimizing roadway layout and mining technology,ensuring safe and efficient mining of mine.According to the geological condition of mine,the occurrence of coal seam and the stratified mining of thick coal seam,the mining technology condition of Laohutai mine is determined.By the comprehensive analysis of rock structure information,provided by the geological drilling and EH-4 resistivity profiling of working face and coal pillar area of the Laohutai mine,the working face separation structure and its spacial scale is determined.By the method of numerical simulationand the study on the deformation and failure law of overlying strata after extra thick coal seam mining,the deformation characteristics,stress distribution and failure characteristics of the overlying strata are determined in different geological and mining conditions,revealing the movement law of overlying strata structure.Based on the research data,got by the theoretical analysis,numerical simulation and microseismic monitoring methods,the distribution characteristics of "three zones" of overlying strata in the Laohutai mine and the mining damage characteristics of overlying strata are determined.Based on the hydrogeological characteristics of the mine,the analysis of water filling characteristics of overlying strata in working face,the influence of the structure of overlying strata on the mining is determined.According to field observation and numerical simulation,strata behavior characteristics and its influence on mining with different structures and mining conditions were obtained.And the mining scheme of the coal mine is optimized and some advice on safe mining is proposed.In thisdissertation,the "three zones" development characteristics of the overlying strata of panels with different mining methods in Laohutai coal mine are determined;the mining damaged area division of the overlying strata is completed;the structure characteristics,dynamic failure process and dynamic evolution characteristics of the stress of the overlying strata of panels are clarified clearly.And finally,the influence of overlying strata movement characteristics on mining is determined.In green shale area,the mining of panels has no flood danger,and the mining height should be increased properly.In fault and sandy conglomerate zones,there exists slight flood danger;therefore,when mining with fully mechanized slicing carving,the slicing number should be increased and the slicing height should be decreased to decrease the failure height of the overlying strata.It is suggested that the panel length in the two areas be decreased from 200 m to 160 m～180 m,and the advancing speed from 1.9m/d to 1.5m/d.In severe danger zones,hydraulic filling mining method is suggested.