Geological Characteristics And Control Factors Of Main Coal Seam Of Xiashihezi Formation In SunTuan Coalmine

SunTuan coalmine located in Huaibei Coalfield is unknown coal seam characterisitics and control mechanism of Xiashihezi Formation,so this problem Seriously affected future production plan.From the core of drilling,logging,geological data,etc.,The paper takes the characteristics of coal seam as the research object,conducting systematic research on the structure and sedimentation of the mining area by using of the basic theories of high-resolution sequence stratigraphy,sedimentology,coal mine geology,logging geology,etc.Exploring the control factors of coal seams by applyng qualitative and quantitative methods in the SunTuan coalmine.?1?Based on the structural characteristics of SunTuan coalmine in Huaibei coalfield,it is determined that is mainly affected by two-stage tectonic movements,the early Yanshanian and the late Yanshanian period.The faults are all normal faults.By analyzing the intrusion thickness of magmatic rock in coal seam,The magmatic rock intruds mainly 8₁ coal seam.in the middle Yanshanian period.The second phase is the late Yanshanian period.The mining area is mainly characterized by the formation of controlled faults?F9,F7,F5?and small"NE"vertical faults on the basis of the original normal fault.?2?The distribution characteristics and isogram of coal thickness is determined.The thickness of 8₂ coal seam is 0-4.31m,the average thickness is 1.70m,the coefficient of variation of coal seam is 81%,the recoverable index is 0.80,which is unstable coal seam;the thickness of 7₂ coal seam is 0-3.62m,and the average thickness is 1.14m.The recoverable index is 0.58,and the coefficient of variation of coal seam is 88%,which is extremely unstable coal seam.The coal seams are distributed in strips,which can be divided into the southern and northern coal-bearing belts and the central non-recoverable areas in the mining area.The north-south coal belt is thick in the middle and thin in the periphery.The coal seam can be medium-thick coal seam.The sulfur content of the whole coal seam shows the downturn.The low-sulfur area is distributed in strips and the ash content is rising.?3?The depositional environments and coal-accumulation characteristics of the major coal-bearing strata of the Lower Shihezi Formation were studied based on core observation,Sedimentary phase marks and phase markers.The result has identified that research area is delta plain and combined effect of the sea and river.The mian sedimentary microfacies include distributary,interdistributary bay,natural levee,flood basin and peat bog.the Shanxi group and the lower stone box group are divided into 2three-order cycles and 6 four-order cycles.On this basis,the coal-bearing strata of the Xiashihe Formation in the research area were divided into 4 five-order cycles,and the modern sedimentary environment analysis method was used to reconstruct the rocks of the main coal seams of the Xiashihe Formation in the study area during different five-order cycles by using the modern sedimentary environment analysis method.?4?Applyng the qualitative and quantitative evaluation methods,the comprehensive control of the main coal seam thickness of the Xiashihezi Formation was carried out.The geological control factors of the coal seam thickness change in the whole mining area were:Sedimentary environment>Late stage erosion>Magma intrusion>Geological structure.