Using water sprays to improve performance of a flooded bed dust scrubber.

Supplemental water sprays were placed along the sides of a continuous mining machine to improve suppression and confinement of the dust cloud under the cutting boom to reduce downwind dust levels. Using a full-scale mock-up of a continuous mining machine, preliminary work showed that these side sprays improved suppression of the dust cloud and redistributed this cloud under the cutting head. This led to reductions in dust levels around the machine and in down-wind airways for some positions of the mining machine. This testing also showed that side spray effectiveness was influenced by the distance from the fresh air ventilation device to the cutting surface, termed the ventilation setback distance. These sprays produced larger reductions in machine and return dust levels at smaller setback distances than at larger setback distances. These side sprays then were installed in similar locations on a mining machine at an underground coal mine operation to evaluate their effectiveness for improving suppression and capture of dust by the flooded-bed dust scrubber. Although sampling could not be conducted successfully in the return, sampling around the mining machine and at the machine operator showed that dust levels decreased with use of these sprays. Further analysis showed that these sprays were most effective at the smaller setback distances, a result confirmed by full-scale laboratory testing.