Coal Assessments

More than half of the electricity produced in the United States is generated by coal-fired power plants. Statistically, the United States has abundant supplies of coal. However, understanding how much of that supply of coal is actually economically recoverable and of sufficient quality to meet current emission standards is important to ensure adequate energy supplies in the future. Therefore, in energy assessments, it is not only essential to determine the in-place coal resources, but also to inventory the coal reserves. Coal reserve estimates provide a more accurate appraisal of how much of the total U.S. coal resource base is realistically available for production in the near and mid-term future.

Photo: Coal extraction in a Powder River, Wyoming
coal mine.

There is often confusion concerning the use of the terms coal “resources” and “reserves.” Although the two terms are frequently used interchangeably, there are significant differences. Coal resources include in-place tonnage estimates determined by summing the volumes for identified and undiscovered deposits of coal with a minimum thickness of 14 inches, 36.6 cm or more for anthracite and bituminous coal; 30 inches, 76.2 cm or more for lignite and subbituminous coal, and under less than a depth of 6,000 feet, 1828.8 m. Coal reserves are a subset of the coal resources. To be classified as reserves, the coal must be considered economically producible at the time of classification, but facilities for extraction need not be in place and operative.

The next generation of U.S. coal assessments will not only be a refinement of the coal resources, but also the systematic determination of the regional coal reserve base in all the major coal provinces in the U.S. The first U.S. coal basin to be evaluated in this new assessment phase is the Powder River Basin, WY (PRB). The PRB is the single most important coal basin in the U.S. production-wise, supplying over 37 percent of the total coal produced in the U.S. in 2003.

The USGS Energy Resources Program research efforts yield modern, digital assessments of the quantity, quality, location, and accessibility of the Nation’s coal resources.

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National Coal Resource
Assessment (NCRA)

National Coal Resource Assessment (NCRA)

The NCRA project was a multi-year effort by the U.S. Geological Survey (USGS) Energy Resources Program to identify, characterize, and assess the coal resources that will supply a major part of the Nation’s energy needs during the next few decades. The purpose of the NCRA was to (1) digitally assess selected coal beds and zones that will be the most important in the next few decades, (2) create publicly available stratigraphic,... [+]

Coal Quality

Coal Quality

The USGS Energy Resources Program researches and provides studies on the quantity, quality, and location of the Nation’s coal resources and has world class research facilities investigating coal petrology and coal quality. These studies address coal extraction, utilization and disposal issues, human health and environmental impact issues, and identify suitable resources for the Nation’s electric power generation.

Coal Databases

Coal Databases

The U.S. Geological Survey Energy Resources Program has developed coal databases to monitor the location, quantity, and physical and chemical characteristics of U.S. coal and coal-related deposits.

Coal database for Cook Inlet and North Slope, Alaska - USGS Digital Data Series 599

Shallow Coal Exploration Drill-Hole Data—Alabama, Georgia, Kentucky, Louisiana, Mississippi, Missouri, North Carolina, South Carolina, Tennessee, and Texas - USGS Open-File Report 2011-1262

USGS Links

NCRDS State Cooperators

External Links

ASTM Committee D05 on Coal and Coke

U.S. Department of Energy Clean Coal Initiative

U.S. Energy Information Administration