US coal basin expected to last the decade, but mining to decline thereafter

The Appalachian Basin includes parts of Ohio, Pennsylvania, West Virginia, Kentucky, Virginia, Maryland and Tennessee. Almost all of the coal now mined in the area is used in eastern states to generate electricity.

The USGS studied 12 of the more than 50 producing coal beds in the Appalachian Basin, with five key coal beds digitally assessed in detail. “We put together stratographic and geochemical databases for each of the five coal beds we assessed,” Lesley Rupert, who led the project, explained to edie. From these, a series of complex maps were produced in order to calculate the volume and tonnage of coal in the area.

Rupert explained “Unlike the other surveys, we analysed just five coal beds, which were the top producers, because the remaining beds were unlikely to be used anyway”.

The five digitally assessed coal beds account for about 12% of the United States’ total coal production. The total original quantity of coal in these five coal beds is estimated to have been about 93 billion short tonnes, of which about 66 million short tonnes remain. Each year just over a billion short tonnes of coal are mined in the United States.

The Appalachian Basin is one of five US regions being studied as part of the USGS National Coal Resource Assessment, which began in 1995. The Colorado Plateau and the Northern Rocky Mountains/Great Plains assessments were completed last year.

The USGS concluded that at current production rates, sufficient high-quality coal resources in these five beds will last throughout the decade. After these and similar coal beds are mined, and assuming current regulations and technology, coal production is expected to decline because much of the remaining coal is thinner, deeper, and higher in ash and sulphur content.

“Resource assessments are an important component in developing environmentally sound ways to extract and use the Nation’s coal resources as part of an effective national energy policy,” said USGS Director Charles Groat.

However, Rupert explained to edie, “We’re probably not going to be doing another survey of this kind. It is very labour intensive”. Instead, the USGS are using the results to provide valuable information for resource managers. “Using the results we’re looking at the marketability of coal areas,” she said.

In addition to evaluating energy production potential, coal resource assessments can be used to aid the identification of areas with potential for coal-bed methane production (see related story), mine flooding, surface subsidence, and acid mine drainage.

With coal currently providing more than half of the US’s electrical needs, thought must urgently go into alternative electricity production. “Electrical demand in the U.S. is expected to increase and Natural Gas is expected to replace depleted coal reserves,” Rupert explained. However, both of these are finite sources and the search for renewable alternatives is becoming increasingly important. “The USGS is beginning to look at geologic renewables,” she added.