The occurrence of Coal Worker's Pneumoconiosis (CWP) has been potentially linked with several characteristics of coal such as rank, volatility, percent content of ash and noncoal components, quartz content, and the presence of several trace elements. According to the National Research Council, numerous epidemiological studies indicate that the incidence of CWP varies significantly with the composition and/or the concentration of the coal mine dust. Although advances in dust-suppression techniques have markedly reduced respirable-dust levels in underground coal mines, the National Research Council has concluded that chemical characteristics of respirable dust from different coal seams should be studied. With this objective in mind, research has been conducted in underground coal mines located in the eastern and midwestem United States, and in the laboratory to characterize the elemental composition of mining-generated airborne dust and laboratory-generated dust derived from samples taken from these mines. The goal of the research is to determine if a relationship exists between mining-generated and laboratory-generated dust from the same mine.