Top coal loss distribution and optimization of coal caving interval in fully mechanized face with large dip angle
To improve the recovery rate of top coal in No.0291 fully mechanized caving face of Tangshan Coal Mine,the amount of top coal loss during production was theoretically calculated from seven locations,including end loss,support interval loss,and initial mining loss,etc.Using drawing interval loss as an optimization object,PFC2D software is used to optimize the coal drawing interval.According to the principle of"stop drawing at any waste",the top coal drawing amounts of different coal drawing intervals are compared.The simulation results show that the top coal drawing amount presents significant fluctuations with the moving of the supports.The 80~560 pieces of coal is drawn with"one cut one caving"interval,50~680 pieces with"two cuts one caving"interval,and 100~1100 pieces with"three cuts one caving"interval.According to the total coal caving amount,efficiency of the"one cut one caving"interval is the highest,with 3832 pieces drawn.Therefore,when the coal drawing interval is optimized to"one cut one caving",the drawing interval loss can be effectively reduced.
fully mechanized top coal cavingtop coal loss distributionPFC numerical simulationcoal drawing interval optimization