sub-bituminous

Many coal plants in the eastern U.S. rely on bituminous coal, which when burned emits higher levels of acid gases than sub-bituminous coal, commonly found in western states.

EPA Tangles With New Critic: Labor Stephen Power 2011

Yet many of the country's most productive sources of anthracite and bituminous coal -- the types with the greatest energy potential -- have been depleted, leaving (as with oil) less productive sources of these types, along with large deposits of less desirable, more heavily polluting sub-bituminous coal, much of it located in Wyoming.

Michael T. Klare: The Era of Xtreme Energy: Life After the Age of Oil 2009

Experts say the technology is especially suitable for low-rank coals like lignites and sub-bituminous coal, which produce less heat when burned due to their high ash content, and are highly polluting.

Cleaning Up Coal's Act 2008

Ukraine has 37.6 billion short tons in proven coal reserves, 17.9 billion short tons of which is anthracite and bituminous coal, and 19.7 billion short tons of which is lignite and sub-bituminous, accounting for about 15 percent of the Former Soviet Union's total reserves.

Energy profile of Ukraine 2008

Indonesia has 5.9 billion short tons of recoverable coal reserves, of which 58.6% is lignite, 26.6% is sub-bituminous, 14.4% is bituminous, and 0.4% anthracite.

Energy profile of Indonesia 2007

About 85 percent of the resources in place are classified as bituminous or sub-bituminous (hard) coal; the rest is lignite (soft brown) coal.

Chapter 9 2000

For practical purposes, the subdivision is based on energy content, with the value of 16,500 kilojoules per kilogram as demarcation between hard coal (bituminous and high-energy sub-bituminous coals) and soft brown coal (lignite and low-energy sub-bituminous coals).

Chapter 9 2000

Generally, the types are bituminous coal (including anthracite), sub-bituminous coal, and lignite.

Chapter 9 2000

They are really a low grade of bituminous coal and are known as sub-bituminous or black lignites.

Steam, Its Generation and Use

Chaco area, but possibly small lenses occur in the predominant sub-bituminous seams.

Tseh So, a Small House Ruin, Chaco Canyon, New Mexico : 1937