Sedimentary Characteristics And Dynamic Zoning Of The Top And Bottom Of No.3 Coal Seam In Longgu Minefield

Most mines in the Eastern of China are working deeply.With the increase of mining depth,the roof pressure of coal seams has been larger gradually,and the roof of coal seams has been seriously degraded.It is more difficult to predict the lithological changes and structure of coal seams in deep mining.Therefore,the lithologic and sedimentary characteristics of the main coal seam roof in the Longgu mine field in the eastern deep mining coal mine are analyzed,and finally the results are obtained through the analysis of petrology,petrography,ore deposit,etc..The results are as follows:1.Sandstone are the main lithology in the coal roofs,which was formed in the river environments.Three cycles(Cl,C2,and C3)can be identified from the coal roof.The C1 cycle becomes the floor.The 3rd coal lies on the top of C1.C2 and C3 are the roofs of 3rd coals.The roof can been identified four types of coal seam floor(lower soft upper,lower soft upper hard type,complex type and mudstone type)and three roof types(lower hard upper,lower soft and hard roof upper,and complex type).The distributions of various types roof and floor can be concluded.The complex roof mainly distributes in the southwest of the mining area.The lower hard upper roof mainly lies in the southeast of the mining area,and the lower soft upper roof i in the mining area.In the north,the complex floor lies in the northeast and southwest of the mining area.The lower hard and soft floor lies in the western part of the mining area.The lower soft and hard floor distribute in the southeast of the mining area,and the mudstone floor distribute in the northwest of the mining area.A small amount appeared in the middle.2.The rock mechanics characteristics of the 3rd coal roof and floor were carried out.The various factors affecting the compressive strength of the coal seam roof are systematically analyzed,and the strong spatial distribution of coal seam roof slate is obtained according to the characteristics and rock mechanics properties of typical boreholes,.The overall pressures of the study area are higher in the east than in the west.3.The distributions of small faults were analyzed.The influence of small faults were evaluated.A comprehensive index model was constructed to calculate the power division of the mining area,and the layout of the top and floor power zones was drawn by the analysis of quantitative relationship of the relevant factors of the coal seam top and bottom power division.It was found that the coal roof dynamics were strongly distributed in the northeast.This achievement provides a certain guiding role for coal mining and disaster prevention,and can effectively reduce production costs,has a certain theoretical and practical application value.