Dynamic Mine Strata Pressure Control Technology of Fully-Mechanized Coal Mining Face Passing Through Concentrated Coal Pillars in Above Seam

In order to solve the powered support crushed problem when a fully-mechanized coal mining face in a low seam of contiguous seams passing through concentrated coal pillars in above seam,taking No. 12306 fully-mechanized coal mining face in Huojitu Mine Shaft of Daliuta Mine as a study object,the paper had an analysis on the mine strata pressure law,powered support working resistance and mine dynamic strata behavior features when the coal mining face passed through the concentrated coal pillars in above seam. According to the analysis,the causes of the dynamic strata behavior would be overlong suspended roof distance of the coal mining face and a large periodic strata weighting step. Thus a large area main roof falling and lost stability of the overburden strata jointing structure in the concentrated coal pillar boundary were affected on the powered supports in the coal mining face,made an impact load on the powered supports in the coal mining face,the legs of the powered support were drawn back with 1. 2 ~ 1. 5 m and serious dynamic mine strata pressure occurred. The technical measures of the tilt control of the coal mining face,adjustment of the periodic strata weighting,enhanced working resistance of the powered support,improved open pressure of the safety valve,speeding advancing rate of the coal mining face rational cutting height were provided to prevent accidents of the powered support in the coal mining face and to ensure the mine safety production.