Monitoring of inhalable coal dust generated from cutting process of high coal mining face and improvement of dust reduction method

In order to grasp the dust production characteristics of inhalable coal dust generated from the cutting process of the high coal mining face and improve the dust reduction measures for the mining face, the 6 m large mining height working face of a mine in Linfen, Shanxi was taken as an example, by arranging coal dust monitoring points near the front and rear drums of the shearer respectively. At the dust monitoring point, SidePak AM520i type personal exposure dust meter was used to measure the dust mass concentration of PM10, PM5, PM2.5 in the large mining height working face under downwind and headwind conditions. At the same time, JZYW-200B interfacial tensiometer and JY-PHb contact angle tester were used to test the surface tension and wettability of different concentrations of mine dust gram (C&C) series dust collectors respectively. The use of water for surface dust reduction reduced the concentration of inhalable coal dust in the cutting of large mining heights. The results show that that the average PM10 dust mass concentration at the upwind side drum of the shearer is 561-577 mg/m3, the average PM5 dust concentration is 489-495 mg/m3, the average PM2.5 dust concentration is 231-242 mg/m3; around the drum on the leeward side of the shearer, the average PM10 dust concentration is 609-614 mg/m3，the average PM5 dust concentration is 508-522 mg/m3，the average PM2.5 dust concentration is 245-256 mg/m3. Whether the tailwind or headwind condition, the fluctuation range of the PM10, PM5 dust concentration around the drum on the leeward side of the shearer has a larger fluctuation range, while the PM2.5 dust concentration fluctuation range has a smaller fluctuation range, and the PM10, PM5, PM2.5 dust concentration is greater than that at the upstream side drum. Under the tailwind condition the dust concentration of PM10, PM5, and PM2.5 around the drum on the windward side of the shearer is lower than that of the headwind condition, and under the headwind condition the dust concentration of PM10, PM5, and PM2.5 around the drum on the leeward side of the shearer is greater than that of the tailwind condition. When the concentration of the dust removal agent of C&C series is 0.1%, the surface tension of C&C series dust collector solution is 33.2 mN/m, and the contact angle is 34.27°. Compared with mine water, its surface tension is reduced by 43.82%, and the contact angle is reduced by 53.86%, so it has good wettability. A surfactant adding device is installed in the air inlet of the working face along the groove, and it is used as the water for dust reduction on the working face. The dust removal efficiency of dust can reach 39.57%-45.11%.