Characteristics of airborne coal mine dust and its implication to coal workers' pneumoconiosis.

摘要

Physical and chemical characteristics of coal mine dust are expected to vary from location to location within a mine, between mines, between coal seams, between coal ranks, between particle sizes, and over time. This information is valuable in understanding the variations in CWP incidence and possibly the cause(s), as well as in establishing the appropriate kinds of dust to use in toxicological research programs studying CWP.;The objectives of this study were to analyze such characteristics of coal mine dust as concentration, particle size distribution and mineral content as a function of sampling location, section, coal mine, and coal seam.;Size selective airborne dust samples were collected using 4-stage cassette impactors at nine different locations in continuous mining sections in each of five coal seams located in the Appalachian bituminous coal field. These coal seams were the Upper Freeport, Pittsburgh, Kittanning, Coalburg, and Pocahontas. Mineralogical analyses were performed by an x-ray powder diffraction photographic technique.;The distributions of total and respirable dust concentrations were fit best by a log-normal distribution. The effects of the coal seam and the sampling location on dust levels were significant. The results of the particle size distribution analyses suggest that coal mine dust has a multi-modal distribution. The effects of the coal seam and the sampling locations were significant. The distributions obtained were often affected by such mine-related variables as ventilation rate, relative humidity, and the section dimensions. Nine minerals commonly found in the coal mine dust samples collected from the coal seams studied were illite, calcite, kaolinite, quartz, dolomite, siderite, gypsum, anhydrite, and pyrite in descending order of magnitude. Relative abundance of all mineral species except siderite and gypsum was coal seam specific and suggests the existence of coal seam variability of mineral content. Although mineral content was affected by sampling locations and the sections within a mine, the magnitude was small when compared with that of coal seams. Mineral content also appears to be affected by particle size, although no particular pattern was observed.