易自燃煤层综放工作面安全开采方法研究

鉴于在坚硬顶板煤层放顶煤过程中出现的顶煤冒落不能控制,煤尘大,可放性差,造成顶煤回采率低的问题,为提高顶煤的冒放性及控制煤层自燃,陕西长武亭南煤矿在111工作面回风平巷交替布置预裂爆破孔和控制孔,采用深孔控制预裂爆破结合动压注水的方法,实现工作面回采率提高8.5%,粉尘质量浓度由12.7 mg/m3降到8.9 mg/m3,并通过在控制孔注阻燃剂使原煤发热量降低470 cal/g,含水量增加2.56%,延缓了煤层的自热过程,改善了工作面的作业环境,实现易自燃高尘厚煤层综放面的安全开采。

Study on Safety Mining Method of Fully-Mechanized Top-Coal Caving in Coal Seam with Easy Spontaneous Combustion and High Coal Dust

Many problems,such as the difficulty of controlling top seam caving,the high dust concentration,the low top-coal recovery rate,may occur in the process of fully-mechanized top-coal caving in hard roof.To improve the cavability of the top-coal and control the spontaneous combustion,the presplitting blasting and controlling boreholes were arranged alternatively in the air-return roadway of coal face 111 in Tingnan coal mine,Changwu,Shaanxi,then the deep hole presplitting blasting combined with dynamic pressure water injection were carried out during the mining operation.Thus,the recovery rate of coal face was improved by 8.5%,the coal dust concentration decreased from 12.7 mg/m3 to 8.9 mg/m3.Meanwhile,through the injection of flame retardants in the controlling boreholes,the calorific value was decreased by 470 calorie per gram,the water content was increased by 2.56%,which effectively delayed the thermal process,improved the working environment,and ensured the safety mining of fully-mechanized sublevel caving in the easy spontaneous combustion and high coal-dust coal seam.