Feasibility and mining lag time analysis of upward mining in shallow buried multi coal seam
The coal seam group is generally mined in downward order,but sometimes it is necessary to mine in upward order.The upper coal seam in the Qinglongsi Coal Mine Field is affected by the burnt area,and the recoverable area is smaller than that of the 5-2 coal seam.In the northwest of the Qinglongsi Coal Mine Field,the 3-1 coal seam is affected by the early small kiln mining,and the integrity of the coal seam is destroyed.Therefore,the first mining area of the mine was arranged in the 5-2 coal seam in the early mining section of the western part of the mine field,and the upper coal seam mining is upward mining.According to the mining influence multiple method,"two zone"height discrimination method and surrounding rock balance method in the upward mining theory,combined with the geological conditions of Qinglongsi Coal Mine,the feasibility of upward mining of the upper coal seam of 5-2 coal seam was analyzed.The results showed that the upper coal seams(3-1,3-2,4-2 coal seam)of Qinglongsi Coal Mine can carry out normal upward mining.According to engineering analogy,empirical statistics and analysis of active period of overlying rock movement,it was concluded that the upward mining lags behind 5-2 coal longwall mining face by no less than 9 months.The analysis results provide reference and theoreti-cal support for the subsequent upward mining of the upper coal seam.
upward mining"two zone"heightsurrounding rock balance methodactive period of overlying rock movementlag time
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