Publications

Survey of Energy Resources 2007

Coal Country Notes

The United States coal resource base is the largest in the world. The US WEC Member Committee reports a proved amount in place at 1 January 2006 of some 447 billion tonnes (based on the Energy Information Administration's 'Demonstrated Reserve Base'). This total is comprised of 244.3 billion tonnes of bituminous coal (including anthracite) with a maximum deposit depth of 671 m and minimum seam thickness of 0.25 m; 163.6 billion tonnes of sub-bituminous (at up to 305 m depth and 1.52 m minimum seam thickness) and 39.3 billion tonnes of lignite (at up to 61 m depth and 0.76 m minimum seam thickness).

The reported proved recoverable reserves amount to 242.7 billion tonnes, equivalent to about 29% of the global total. They comprise 112.3 billion tonnes of bituminous coal (including anthracite), 100 billion tonnes of sub-bituminous and 30.4 billion tonnes of lignite. The overall ratio of proved recoverable reserves to the proved amount in place is 0.54. This ratio varies widely from one rank to another, reflecting relative degrees of accessibility and recoverability: bituminous deposits average 0.46, sub-bituminous 0.61 and lignite 0.77. Open-cast or surface mining techniques can be applied to 27% of bituminous reserves, to 43.4% of the sub-bituminous and to 100% of the lignite.

Data for proved amount in place and recoverable reserves are measured and indicated (proved and probable), in a commingled data base. The data cannot be separated into 'proved only' and 'probable only'.

On top of the tonnages summarised above, the US WEC Member Committee reports enormous quantities of coal as 'estimated additional amounts in place': in total these come to well over a trillion tonnes, composed of 445 billion tonnes of bituminous, 274 billion sub-bituminous and 394 billion lignite. These estimates are derived from a US Department of the Interior study of coal resources as at 1 January 1974, but are regarded as still providing valid indications of the magnitude of the USA's additional coal resources. Data on the estimated additional amount in place are primarily inferred. These resources extend deeper than the proved amount in place, include thinner beds in some areas, and are based on older source data in many cases. The estimated additional amount in place has been adjusted only to indicate the arithmetic difference with proved amount in place.

Coal deposits are widely distributed, being found in 38 states and underlying about 13% of the total land area. The Western Region (owing largely to Montana and Wyoming) accounts for about 47% of the EIA's 'Demonstrated Reserve Base', the Interior Region (chiefly Illinois and western Kentucky) for 32% and the Appalachian Region (chiefly West Virginia, Pennsylvania and Ohio) for 21%. Bituminous coal reserves are recorded for 27 states, whereas only 8 states have sub-bituminous reserves, of which 90% are located in Montana and Wyoming, and 10 have lignite reserves, mostly in Montana and Texas.

US coal output is the second highest in the world, after China, and accounted for about 18% of global production in 2005. Included in the USA's 2005 coal production of 1 038.6 million tonnes is 12.1 million tonnes of recovered waste coal. Coal is the USA's largest single source of indigenous primary energy; power stations, CHP and heat plants accounted for 82% of domestic coal consumption in 2004. Coal exports amounted to 45 million tonnes in 2005: the USA remains a leading supplier of coking coal and other bituminous grades.