CO2, CO, and Hg emissions from the Truman Shepherd and Ruth Mullins coal fires, eastern Kentucky, USA

Carbon dioxide (CO2), carbon monoxide (CO), and mercury (Hg) emissions were quantified for two eastern Kentucky coal-seam fires, the Truman Shepherd fire in Floyd County and the Ruth Mullins fire in Perry County. This study is one of the first to estimate gas emissions from coal fires using field measurements at gas vents. The Truman Shepherd fire emissions are nearly 1400 t CO2/yr and 16 kg Hg/yr resulting from a coal combustion rate of 450–550 t/yr. The sum of CO2 emissions from seven vents at the Ruth Mullins fire is 726 ± 72 t/yr, suggesting that the fire is consuming about 250–280 t coal/yr. Total Ruth Mullins fire CO and Hg emissions are estimated at 21 ± 1.8 t/yr and > 840 ± 170 g/yr, respectively. The CO2 emissions are environmentally significant, but low compared to coal-fired power plants; for example, 3.9 × 106 t CO2/yr for a 514-MW boiler in Kentucky. Using simple calculations, CO2 and Hg emissions from coal-fires in the U.S. are estimated at 1.4 × 107–2.9 × 108 t/yr and 0.58–11.5 t/yr, respectively. This initial work indicates that coal fires may be an important source of CO2, CO, Hg and other atmospheric constituents.