Geologic influences on the distribution of potentially hazardous trace elements in lignites, Gulf Coast Province, U.S.A.

Conference · Wed Dec 31 04:00:00 EST 1997

OSTI ID:324780

Warwick, P D; Crowley, S S; San Filipo, J R ^[1]

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1. Geological Survey, Reston, VA (United States)

As a part of the National Coal Assessment Project of the US Geological Survey (USGS), the authors are characterizing the quantity and quality of coals expected to be mined during the next quarter century in the Gulf Coast Province (Gulf of Mexico coastal plain area) of the US. The primary areas of interest are within the states of Texas, Louisiana, and Mississippi. However, a recently compiled map of the Gulf Province shows that the coal-bearing rocks in the region extend into the adjoining states of Arkansas, Tennessee, and Alabama. The major interval of study is the Wilcox Group (Paleocene-Eocene); other selected coal-producing intervals (such as Upper Cretaceous rocks, and the Eocene Jackson and Claiborne Groups) that are producing or have potential for producing coal will also be investigated. In the National Coal Assessment Project, the authors are particularly interested in the distribution of potentially hazardous air pollutant elements (As, Be, Cd, Cr, Co, Hg, Mn, Ni, Pb, Sb, Se, and U) that were cited by the US Clean Air Act Amendments of 1990. The goal is to produce a regional stratigraphic and geochemical database that is accessible through Geographic Information Systems and the World Wide Web. Most of the coal in the Gulf Province is lignite produced from the Wilcox Group and is used as fuel for mine-mouth electric-power generating plants. Gulf Coast coal quality is generally below that of other major coal-producing regions of the US; mean values (on an as-received basis) for the mined Gulf Province coals are: ash yield, 16%; sulfur content, 1 %; and calorific value of 15 MJ/kg. The province produces about 60 million short tons of coal annually from the states of Texas and Louisiana. Coal production is expected to expand to other states in the province in the near future. Geochemical data (about 250 samples) have been obtained from the coal mining industry, and the archives of USGS National Coal Resource Data System (NCRDS), which contains data collected over the last 15 years. In addition, the authors have analyzed coal and rock samples (about 150 samples) collected from the Gulf Province over the last three years. Many of their recently acquired samples were collected from multiple intervals within mined coal beds in the region. Such detailed sampling allows them to study lateral and vertical variations in the concentrations of selected elements within a single minable coal bed. The coal quality data that they have obtained for the Gulf Province has an uneven distribution; geochemical data are concentrated in mine areas and sparsely distributed in areas that are not currently being mined. This uneven distribution has not allowed regional-scale isoline maps to be produced for the individual elements. Instead, the authors have produced ``bubble maps`` which indicate concentration levels of selected elements at each sample location. On a regional scale, their data suggest that samples from Arkansas and Mississippi (Wilcox), and samples from eastern Texas (Jackson), are enriched in all of the potentially hazardous air pollutant elements, compared to samples from the Wilcox of Texas and Louisiana.

• OSTI ID: 324780
• Report Number(s): CONF-970931--
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
AIR POLLUTION
COAL DEPOSITS
ENVIRONMENTAL IMPACTS
GEOCHEMISTRY
INFORMATION SYSTEMS
LIGNITE
LOUISIANA
MISSISSIPPI
TEXAS