Feasibility Study Of Upward Mining At Baizi Coal Mine

In the process of upward mining,if the lower coal seam is used in pillar mining,it was under the influence of pressure,the instability of the residual coal column in the interlayer and the lower coal seam is possible,will be cause the collapse of the overlying rock formation and the instability of the floor of the long wall face plate,To threaten the safety production of upper coal seam mining.Therefore,It is necessary to study the feasibility of mining on top of the coal seam.The paper studies the Baizi Coal mine,Methods of theoretical analysis,physical simulation and numerical simulation,The feasibility of the wall mining of the top coal seam #5 of coal seam #8 is studied in this paper.The theoretical analysis will take the pressure as the key parameter to analyze the feasibility of upward mining,the prediction formula for the pressure of mining is given,conclusion maximum damage depth is 3.2m between the coal seam #8 and the coal seam #5 smallest layer of 20 m,the stability factor of the tensile strength and shear strength of the interlayer was 5.9 and 4.1,based on the theory of effective area obtain stability coefficient of the coal column in the coal seam of lower #8 is 2.2,It shows that interlayer rock body and coal pillar for the coal seam #8 hold steady.The study of physical simulation experiments shows that the maximum support pressure in the coal seam #8 is 2.965Mpa;In the process of the long wall of the coal seam #5,the old roof first came in about 58 m,the average period is 16.7m,the compressive pressure in the process affects only the depth of the interlayer,the interlayered rock remains stable;a significant decompression zone is formed in the bottom layer of the subsurface of the coal seam #5 bed zone,the stress concentration of the coal column and the sensor on the lower part of the coal wall in front of the coal wall is only applied when the roof is pressed,but pressure value of the coal column supported by the monitoring is less than 4MPa,far lower than the load strength of the coal seam #8 pillar,indicates that the coal column of the coal seam #8 is stable In the process of coal seam #5 upward mining;The numerical simulation is revealed the stress distribution and evolution of coal column and interlayer rock in the coal seam #8 In the process of coal seam #5 length,It shows the Baizi Coal mine in upward mining interlayer rock body and the coal pillar of the lower volt #8 has sufficient strength,there will be no instability.The results of the paper are of guiding significance for upward mining of Baizi Coal mine,there is also good reference for the upward mining of other similar mining conditions coal mine.