Dust control challenges exist in numerous mining applications and is especially prevalent in confined production spaces like mining faces. Water sprays are the most economical and technically feasible means of reducing dust concentrations in a wide range of applications. This study investigated the respirable dust knockdown performance and submicron particle suppression behavior for a typical mining spray nozzle operating at pressures ranging from 100 to 800 psi. A confined chamber dust removal evaluation approach and an optical particle counter were used for this study. For respirable dust knockdown, high spray pressures were more effective in lowering dust concentrations. However, submicron-sized particles are difficult to remove; at 100-psi water pressure, the knockdown fraction for submicron particles remained at only 40 % at the end of a 1-hr test. The lowest suppression effective size boundary was identified from 0.465 to 0.897 µm under a tested pressure range. Resuspension of submicron material was observed at all water pressure levels after the start of the spray operation. The resuspended sub-micron dust remained airborne for different durations under different spray pressures. Overall, results show a low capture efficiency and a high resuspension possibility for micron- or nano-scale particles under testing conditions.
