The Tiptop Coal Mine Fire, Kentucky: Preliminary Investigation of the Measurement of Mercury, Carbon Dioxide, and Carbon Monoxide from Coal-Fire Gas Vents

摘要

The Tiptop underground mine fire in the Skyline coalbed of the Middle Pennsylvanian Breathitt Formation was investigated in rural northern Breathitt County, Kentucky, in May 2008 and January 2009, for the purpose of determining the concentrations of CO_2,CO, and Hg in the vent and measuring gas-vent temperatures. Concentrations of CO_2 peaked at 2.0% and >6.0% (v/v) and CO at 600 ppm and >700 ppm during field analysis in May 2008 and January 2009, respectively. For comparison, these concentrations exceed U.S. Occupational Safety & Health Administration (OSHA) safety exposure limits (0.5% CO_2 and 50 ppm CO), although the site is not currently mined. Mercury, in excess of 500 (May) and 2,100 (January) μg/m~3 in the field, also exceeded the OSHA eight-hour exposure limit (50 μg/m~3). These gases are diluted as they exit and migrate away from a gas vent, but temperature inversions and other meteorological conditions could lead to unhealthy concentrations in small nearby towns. Variation in gas temperatures, up to nearly 300 °C during the January visit to the fire versus <50 °C in May, demonstrate the large temporal variability in fire intensity at the Tiptop mine. These preliminary results suggest that emissions from coal-fires may be important but additional data are required which address the significant variation in composition, flow, and temperature of vent gases.