A Laboratory Investigation of Underside Shield Sprays to Improve Dust Control of Longwall Water Spray Systems

Researchers at the National Institute for Occupational Safety and Health (NIOSH) performed laboratory testing to improve longwall dust control by examining the use of underside shield sprays in conjunction with the longwall directional spray system. In a field survey of longwall operations, NIOSH researchers observed dust clouds created by the fracturing and spalling of coal immediately upwind of the headgate drum that migrated into the walkway, exposing mining personnel to respirable coal dust. The goal of this research was to create an effective traveling water curtain to prevent this dust from reaching the personnel walkway by redirecting it toward the longwall face. The location, orientation, and pressure of the water sprays were the primary testing parameters examined for minimizing dust exposure in the walkway. Laboratory testing indicates that the use of underside shield sprays on the longwall face may be beneficial toward reducing respirable dust exposure for mining personnel.