三软不稳定煤层深孔注水防尘与注浆防片帮技术
Dust Prevention with Deep Borehole Water Injection and Spalling Prevention with Grouting in Unstable Seam with Soft Roof, Coal and Floor
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摘要: 为降低综放工作面煤尘浓度及控制煤壁片帮,针对白坪煤矿三软煤层情况,对工作面煤层进行了深孔注水防尘与注浆加固煤壁。首先采用ZDY-3200钻机施工60~80 m深的注水孔;然后在注水孔周围6 m内使用ZBQ-6/2.5型钻机施工深9 m、间距0.6~1.2 m、排距0.8~1.0 m的煤壁注浆孔;选用MRB125/31.5型注水泵用12~14 MPa压力对煤层注水压裂,再用5~8 MPa压力反复间歇式注水。现场应用效果表明,采用该技术能够使煤层水分由4%增至5%~6%,回风巷煤尘平均质量浓度269 mg/m3降至108 mg/m3;工作面煤壁片帮范围由占煤壁总长的50%~70%减少到10%~30%,有效地解决了煤壁片帮问题。Abstract: In order to reduce the high coal dust density and serious coal wall spalling in the fully mechanized top coal caving mining face, according to the seam co nditions with soft roof, coal and floor in Baiping Mine, the deep borehole water injection for dust control and the grouting for the coal wall reinforcement were conducted in the seam of the coal mining face ZDY-3200 dilling rig was firstly applied to dril a water borehole with a depth of 60~80 m.ZBQ-6/2.5 mode drilling rig was applied ab out 6 m near the water injection borehole to drill a grouting borehole on the coal wall with a depth of 9 m.The MRB125/31.5 mode water injection pump was applied to t he seam hydraulic fracturing with a pressure of 12~ 14 MPa and after the seam fracturing, an intermittent water injection with a pressure of 5~8 MPa were repeatedly co nducted.The site application effect showed that the technology applied could make the seam water content increased from 4% to 5%~6% and the average dust content i n the air returning gateway was reduced from 269 mg/m3 to 108 mg/m3. The coal wall spalling scope of the coal mining face was reduced from 50%~70% to 10%~30% and the spalling problem was effectively controlled.