低位综放工作面提高顶煤回采率的放煤方式优化

Optimization of coal drawing method for improving top coal recovery rate in low level fully-mechanized caving face

针对古城煤矿低位综放工作面顶煤回采率低的问题,以S1306低位综放工作面为背景,分析了现有放煤方式。首先,通过建立不同放煤方式与放煤口长度的PFC数值计算模型,分析了不同放煤口长度以及相同放煤口长度、不同放煤方式下顶煤回采率;其次,提出了双口间隔动态放煤方式,对比分析了单口顺序放煤、双口顺序放煤以及双口间隔动态放煤的顶煤回采率;最后,研究了不同采放比对3种放煤方式顶煤回采率的影响。研究表明:低位综放工作面顶煤回采率随着放煤口长度的增大而逐渐减小;放煤口长度一定时,单口顺序放煤顶煤回采率大于双口顺序放煤的顶煤回采率;双口间隔动态放煤顶煤回采率相较于单口顺序放煤提高了约8.44%,放煤时间节省了46%,且放煤均衡性优于单口顺序放煤与双口顺序放煤;双口间隔动态放煤和单口顺序放煤的顶煤回采率均随着采放比的增大而增大,当采放比小于1∶1时,双口间隔动态放煤顶煤回采率大于单口顺序放煤方式,当采放比大于1∶1时,两者之间差距明显减小,但双口间隔动态放煤的时间大大缩短。因此,双口间隔动态放煤方式结合了低位综放工作面条件下单口放煤方式顶煤回采率高和双口放煤方式放煤时间短的优势。

In response to the problem of the top coal recovery rate in the low level fully-mechanized top caving face of Gucheng Coal Mine,taking the No.S1306 low level fully-mechanized caving face as the background,the existing coal caving methods were analyzed.Firstly,by establishing PFC numerical calculation models for different coal caving methods and coal caving mouth lengths,the top coal recovery rate was analyzed under different coal drawing mouth lengths and the same coal drawing mouth lengths;secondly,a dual port interval dynamic coal drawing method was proposed,and the top coal recovery rates of single port sequential coal drawing,dual port sequential coal drawing,and dual port interval dynamic coal drawing were compared and analyzed;finally,the impact of different mining and drawing ratios on the top coal recovery rate of three coal drawing methods was studied.Research shows that the recovery rate of top coal in low level fully-mechanized caving face gradually decreases with the increase of the length of the coal drawing port;when the length of the coal drawing port is fixed,the top coal recovery rate of single port sequential coal drawing is greater than that of dual port sequential coal drawing;the recovery rate of top coal in dynamic coal drawing with double port interval has increased by about 8.44%compared to single port sequential coal drawing,saving 46%in coal drawing time,and the coal drawing balance is better than that of single port sequential coal drawing and dual port sequential coal drawing;the top coal recovery rate of dual port interval dynamic coal drawing and single port interval sequential coal drawing both increase with the increase of mining ratio.When the mining ratio is less than 1∶1,the top coal recovery rate of dual port interval dynamic coal drawing is greater than that of single port interval sequential coal drawing.When the mining ratio is greater than 1∶1,the difference between the two is significantly reduced,but the time for dual port interval dynamic coal drawing is greatly reduced.Therefore,the dual port interval dynamic coal drawing method combines the advantages of high top coal recovery rate and short coal drawing time of the single port coal drawing method under the conditions of low level fully-mechanized caving face.