Comparison of mineral content in respirable coal mine dust samples estimated using FTIR, TGA, and SEM-EDX

Since the mid-1990s, there has been a resurgence of severe lung disease among US coal miners. This has prompted efforts to better characterize and monitor respirable dust exposures-especially with respect to mineral content sourced from rock strata surrounding the coal, which is believed to play a central role in many cases of disease. Recently, a rapid analysis method for silica (quartz) has been developed using direct-on-filter Fourier-transform infrared (FTIR) spectroscopy. It can also be used to determine kaolinite, presumably a primary silicate mineral in many coal mines. Other methods, including thermogravimetric analysis (TGA) and scanning electron microscopy with energy dispersive x-ray (SEM-EDX), can also be used to estimate mineral content in respirable coal mine dust. However, there have been few efforts to compare results across multiple methods. This study compares estimates of mineral content derived from FTIR, TGA, and SEM-EDX on respirable dust samples collected in 16 underground coal mines across the US.