Coal geology of the U.S. gulf coastal region

The US Geological Survey (USGS) is conducting a comprehensive assessment of the major coal regions of the country. In this program, known as the National Coal Resource Assessment, the quantity and quality of coals that are expected to be mined during the next 30 years will be characterized. For the Gulf Coast region, the evaluation will include reviews of the stratigraphic setting, resource potential, and the quality of the lignites in four coal-producing areas. These areas are: the Sabine Uplift (including parts of Texas and Louisiana), Northeast Texas, Central Texas, and South Texas. The results of these efforts will be a series of digital Geographic Information System (GIS) maps, text, and tables that will be published in a CD-ROM format. These products, along with a national summary CD-ROM, are expected to be completed in 1999. This paper is to present a review of Gulf Coast coal geology and to outline the USGS assessment efforts for the Gulf Coast region. Most coal in the Gulf Coast area is produced from the Paleocene Wilcox Group, and minor amounts of coal are produced from the Ecocene Jackson and Claiborne Groups. Initial results indicate that for coals being mined in the Sabine Uplift, Northeast,more » and Central Texas areas mean moisture values are about 34%, mean ash yields range from 12 to 15%, and mean calorific values range from about 5,800 to 6,900 Btu/lb (all data are on an as-received basis). Detailed bed and zone analysis in all areas indicate that resource figures will be greater than previous estimates that have usually combined multiple coal horizons to estimate cumulative coal thicknesses for a formation. Ongoing research in the Sabine Uplift and Northeast study areas suggests that coal zones in both the upper and lower Wilcox may be more laterally extensive than previous studies indicate.« less