(203e) The Characterization and Use of Limestone Rock Dusts in Coal Mines to Prevent Dust Explosions

Coal dust generated during the extraction of coal from underground coal seams represents a serious explosion hazard. The prevalence of high-shear equipment in Longwall mining produces finer coal dust and increases the dust explosion concern. Limestone rock dust has been used for many decades in coal mines to provide an inert and heat absorbing component to the mine dust such that the dust becomes non-explosible. Requirements on the amount and characterization of such rock dust has become more stringent in recent years. Now mine dust must be maintained at an 80% incombustible content. Recommendations to increase the fine fraction of the rock dust from 70% passing through 200 mesh sieves and to attain a minimum specific surface area have been made. This presentation will cover recent work by the Pittsburgh Mining Research & Development Branch of the National Institute of Safety and Health (NIOSH) on rock dust characterization for such use in coal mines.