Coal Washability Data Trends in Eastern Kentucky
Overfield, B.L., Weisenfluh, G.A., and Eble, C.F.
Kentucky Geological Survey, University of Kentucky, Lexington, KY
Economic development of eastern Kentucky coal resources is increasingly affected by the quality of the remaining coal deposits. Much of the coal currently being mined in that region must be processed to reduce sulfur and ash content to meet contract specifications. In recent years, the Kentucky Geological Survey has acquired significant numbers of industry coal-quality data, many of which include washability and bench analyses in addition to standard whole-seam proximate data.
The objective of this study was to study washability behavior with respect to geographic and stratigraphic variation, in order to develop a classification of Kentucky coals based on these properties. Three coal-quality data sample sets for eastern Kentucky were selected on the basis of availability of information. Washability data and raw quality data were analyzed by coal bench, and average sulfur, ash, and Btu values were recorded. Washability data were then compared to raw quality data, and changes in sulfur, ash, and Btu were analyzed. Data from all three sample sets were then compared to assess trends. Linear reductions in ash in most coal benches were standard, whereas sulfur changes were highly variable. Linear reductions in sulfur occurred in some benches, whereas, an increase in sulfur occurred in others, presumably related to variable composition of the ash fraction.