Applied study on water injection and dust reduction technology of fullymechanized coal mining face in high gassy and outburst seam

In order to solve a serious dust pollution problem occurred in the production period of the fully mechanized coal mining face in a high gas outburst seam,the available gas drainage boreholes in the air returned gateway of the coal mining face were applied to make the dust control practices with the water injection in the seam.Based on the experiment measurement and statistic analysis,an analysis study was conducted on the variation conditions of the borehole water injection volume,the water injection flow and the water injection pressure in the water injection process.An investigation was conducted on the water content increased before and after the water injection and the dust effect after the water injection and dust control.The study showed that After the gas drainage practiced in the fully－mechanized coal mining face in the high gas and outburst seam,the gas drainage boreholes were applied to the dynamic and static pressure combined water injection and dust control.The gas drainage borehole technology had a strong operability and could highly reduce the construction work load of the seam water injection borehole.After the water injection completed,the water content of the coal in the coal mining face could be increased by over 1%,the original total dust at the driver location was reduced from 1 335.5 mg/m3to 681.1 mg/m3,the respirable dust was reduced from 358.6 mg/m3to 167.1 mg/m3and the dust control efficiency was 49.0%and 53.4%individually.The total dust density at the downside with a distance of 15 m of the coal shearer was reduced from the original 1 108.9 mg/m3to 526.8 mg/m3, the re￣spirable dust was reduced from 303.9 mg/m3to 145.8 mg/m3and the dust control efficiency was 52.5%and 52.0%individually.