Coal Quality in Area of Sand Mountain and Lookout Mountain, Southern Appalachian Mountains, Georgia, Tennessee, and Alabama
S. Lynn Coleman, Thomas L. Crawford
More than 10 coal beds of Pennsylvanian age crop out around Sand Mountain and Lookout Mountain in Georgia, Tennessee, and Alabama. These beds were deposited in barrier and fluvial environments. Few determinations of modern coal-quality data have been made for these coals, although they have been mined for more than 100 years. To evaluate their quality, 47 coal samples from beds 1, 2, 3, 4, 5, 5A, 6, 8, 9, 9A, and 10 were analyzed for ultimate and proximate values, calorific values, forms of sulfur, ash-fusion temperatures, free-swelling indices, and 60 major, minor, and trace-element concentrations.
Most samples have less than 1% total sulfur and have low pyritic and organic sulfur contents. The ash content has geometric mean value of about 8%. The mean calorific value is just above 13,000; some samples have values above 15,000 Btu. The calculated coal rank ranges from low to medium volatile bituminous. However, the rank reverses in the Lookout Mountain coal, suggesting possible tectonic intervention. Because of high free-swelling indices and low concentrations of volatiles, sulfur, and ash, most of these coal beds contain premium quality metallurgical or metallurgical-blend coal.
In some coal beds, the concentrations of CaO, Na2O, P2O5, MgO, and chlorine show wide differences from the overall geometric mean, indicating changing deposition or tectonic conditions. The geometric mean concentrations of minor and trace lithophile elements do not display large differences when compared to other eastern U.S. bituminous coal samples. Chalcophile elements such as silver, arsenic, cobalt, mercury, selenium, and zinc are present in concentrations that may be related to depositional or diagenetic processes. Antimony content is high in some samples.
AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.