Laboratory Investigation of Underside Shield Sprays Used in Conjunction with a Directional Spray System to Lower Respirable Dust Exposures on Longwalls

By Scott Klima, mining engineer, NIOSH

Previous testing was performed by researchers at the National Institute for Occupational Safety and Health (NIOSH) to improve longwall dust control using underside shield sprays with a longwall directional spray system. This testing provided encouraging results toward respirable dust exposure reductions for longwall personnel, achieving as high as 99% dust reduction at some sampling locations along the longwall personnel walkway. Additional laboratory testing was conducted to test these underside shield sprays in conjunction with a shearer-clearer spray system located on the longwall shearer body. The purpose of this testing was to determine if the underside shield sprays interacted positively or negatively with the shearer-clearer sprays. Results from this testing indicate that while the shearer-clearer system influences where the respirable dust particles are directed, underside shield sprays can still lower respirable dust exposure for longwall personnel.