Respirable dust characterization using SEM-EDX and FT-IR: A case study in an Appalachian coal mine

Respirable coal mine dust still represents a serious occupational hazard. Significant resurgence of lung disease among US coal miners in central Appalachia has highlighted the knowledge gap surrounding detailed dust characteristics. This paper presents a case study of dust characterization in a central Appalachian underground coal mine. Respirable dust samples were collected in the intake, near the feeder breaker, and downwind of an active roof bolter, as well as in three downwind locations during four separate continuous miner cuts. The dust was characterized using scanning electron microscopy with energy dispersive X-ray (SEM-EDX) to estimate particle size and mineralogy distributions, and Fourier Transform-Infrared (FT-IR) spectrometry to estimate silica and kaolinite content. SEM-EDX results were generally consistent with previous results in other mines, including indication of relatively high mineral content, especially alumino-silicates, but low coal content in dust samples collected near the roof bolter and continuous miner. The SEM-EDX and FT-IR results were in reasonable agreement for silica (quartz) mass content, which was below 10% in all samples based on the FT-IR. For kaolinite, which was typically around 20%, the SEM-EDX tended to overpredict the FT-IR - at most, measuring 37% kaolinite when the FT-IR measured 20%.