COAL QUALITY CHARACTERISTICS OF TERTIARY COALS FROM CHILE: A GIS-BASED APPROACH

Coal quality parameters including proximate and ultimate analyses, forms-of-sulfur, and major and trace element concentrations, have been determined for 21 coal samples from active mines in the Arauco, Valdivia, and Magallanes basins of Chile. Arauco bituminous coal samples (6 channel samples, as-received basis) from the Trongol and Lebu mines average 13,470 Btu/lb (7,480 kcal/kg), 5.6 percent ash, and 2.6 percent S, comparable with coals of similar rank mined in the Appalachian basin of the USA (average 12,790 Btu/lb, 11 percent ash, 2.1 percent S). On a whole-coal, remnant moisture basis (approximately equivalent to ASTM as-determined), average As and Hg concentrations are 1.0 and 0.07 ppm, respectively, lower than the average concentrations of these elements in Appalachian coals (average 35.4 ppm As, 0.2 ppm Hg). Valdivia lignitic to subbituminous coal samples (5 channel samples) from the Mulpún and Milahuillín mines average 8,480 Btu/lb (4,710 kcal/kg), 17.4 percent ash, and 1.11 percent S, slightly higher than the average values of these quality parameters for coals of similar rank mined from the Powder River basin of the USA (average 8,090 Btu/lb, 7.6 percent ash, 0.7 percent S). Valdivia basin coal samples average 15.5 ppm As and 0.5 ppm Hg, higher than the concentrations of these elements in Powder River coals (average 5.3 ppm As and 0.1 ppm Hg). Lignitic to subbituminous coal samples from the Pecket mine (10 channel samples) in the Magallanes basin average 7,520 Btu/lb (4,180 kcal/kg), 17.5 percent ash, and 0.5 percent S, higher in ash and lower in S than similar rank Powder River coals. Pecket coal samples average 1.2 ppm As and 0.05 ppm Hg, lower than the concentrations of these elements in Powder River coals. These coal quality data are spatially georeferenced and included in a GIS with data layers containing information on coal basins, geology, hydrology, urban areas, and transportation and utility infrastructure. This work is in support of the USGS World Coal Quality Inventory (WoCQI) global GIS database, which is anticipated to provide an accessible, reliable, and modern source of coal quality data and related information.