(7)Comparison of Coal vs. Mineral Mass Fractions in Respirable Dust in Appalachian Coal Mines

摘要

Respirable dust in coal mines is an occupational health hazard, and chronic exposures can lead to irreversible lung diseases such as Coal Worker's Pneumoconiosis and silicosis. Much of what is known about dust exposures has been learned from conventional monitoring efforts, which focus on two main metrics: the total mass concentration of particles (mg/m~3) in the respirable size range and the mass fraction of quartz in this range. However, recent and unexpected increases in lung disease incidence amongst coal miners in the US and elsewhere, have prompted many questions regarding what is not yet known about respirable dust - including its whole composition. Thermogravimetric analysis (TGA) is relatively quick and inexpensive, and can provide additional information about dust samples. Namely, the mass fractions of coal and non-coal (i.e., total mineral matter) can be estimated; and in some cases the carbonate (and non-carbonate) mineral fractions can also be estimated. Such information could advance the understanding of how conditions and activities in the mine relate to dust composition, as well as provide insights into miner health outcomes with respect to dust exposure characteristics. This paper presents TGA results from respirable samples collected in various locations of seven underground mines in Appalachia. The results demonstrate that the ratio of coal to total mineral mass can be quite low, and that carbonate and non-carbonate mass fraction can be very high.