Dust Control and Cooling Technology of Hybrid Water Injection

In order to reduce the dust concentration and the temperature of the fully-mechanized face, the hybrid water injection, namely using static pressure water infusion in dynamic pressure area and dynamic pressure water infusion in static pressure area, was designed. According to the condition of the fully-mechanized caving face in Dongtan Coal Mine, layout of drill holes was ensured, equipments were selected, and field application was carried out. The results show that the moisture content of the coal inreases 1.6% averagely, and the wetted radius of the coal is 7.3 m; the average dedusting rate at the coal drop and moving support positions is about 70% averagely; the temperature in the working face reduces 1.1 ℃, which indicates that the hybrid water injection wets the coal effectively, and achieves good dedusting and cooling effects.