Coal - Classifications Of Coal

bituminous lignite black million

There are four basic types of coal. Classifications, or "coal ranks," are based on how much carbon, volatile matter, and heating value are contained in the coal.

  • Anthracite, or hard coal, is the highest ranked coal. It is hard and jet black, with a moisture content of less than 15%. Anthracite is used mainly for generating electricity and for space heating. It contains approximately 22 to 28 million Btu per ton, with an ignition temperature of approximately 925 to 970 degrees Fahrenheit. Anthracite is mined mainly in northeastern Pennsylvania. (See Figure 4.1.)
  • Bituminous, or soft coal, is the most common coal. It is dense and black, with a moisture content of less than 20% and an ignition range of 700 to 900 degrees Fahrenheit. Bituminous coal is used to generate electricity, for space heating, and to produce coke. Bituminous coal contains a heating value range of 19 to 30 million Btu per ton. It is mined chiefly in the Appalachian and Midwest regions of the United States. (See Figure 4.1.)
  • Sub bituminous coal, or black lignite, is dull black in color and generally contains 20 to 30% moisture. Black lignite is used for generating electricity and for space heating. It contains 16 to 24 million Btu per ton. Black lignite is mined primarily in the western United States. (See Figure 4.1.)

TABLE 4.1

Coal production, selected years, 1949–2003
(Million short tons)
Rank Mining method Location
Year Bituminous coal1 Subbituminous coal Lignite Anthracite1 Underground Surface East of the Mississippi1 West of the Mississippi1 Total1
1Beginning in 2001, includes a small amount of refuse recovery.
2Included in "Bituminous coal."
R = Revised.
P = Preliminary.
E = Estimate.
Note: Totals may not equal sum of components due to independent rounding.
Web Pages: For data not shown for 1951–1969, see http://www.eia.doe.gov/emeu/aer/coal.html. For related information, see http://www.eia.doe.gov/fuelcoal.html.
SOURCE: "Table 7.2. Coal Production, Selected Years, 1949–2003 (Million Short Tons)," in Annual Energy Review 2003, U.S. Department of Energy, Energy Information Administration, Office of Energy Markets and End Use, September 7, 2004, http://www.eia.doe.gov/emeu/aer/pdf/aer.pdf (accessed September 28, 2004)
1949 437.9 2 2 42.7 358.9 121.7 444.2 36.4 480.6
1950 516.3 2 2 44.1 421.0 139.4 524.4 36.0 560.4
1955 464.6 2 2 26.2 358.0 132.9 464.2 26.6 490.8
1960 415.5 2 2 18.8 292.6 141.7 413.0 21.3 434.3
1965 512.1 2 2 14.9 338.0 189.0 499.5 27.4 527.0
1970 578.5 16.4 8.0 9.7 340.5 272.1 567.8 44.9 612.7
1971 521.3 22.2 8.7 8.7 277.2 283.7 509.9 51.0 560.9
1972 556.8 27.5 11.0 7.1 305.0 297.4 538.2 64.3 602.5
1973 543.5 33.9 14.3 6.8 300.1 298.5 522.1 76.4 598.6
1974 545.7 42.2 15.5 6.6 278.0 332.1 518.1 91.9 610.0
1975 577.5 51.1 19.8 6.2 293.5 361.2 543.7 110.9 654.6
1976 588.4 64.8 25.5 6.2 295.5 389.4 548.8 136.1 684.9
1977 581.0 82.1 28.2 5.9 266.6 430.6 533.3 163.9 697.2
1978 534.0 96.8 34.4 5.0 242.8 427.4 487.2 183.0 670.2
1979 612.3 121.5 42.5 4.8 320.9 460.2 559.7 221.4 781.1
1980 628.8 147.7 47.2 6.1 337.5 492.2 578.7 251.0 829.7
1981 608.0 159.7 50.7 5.4 316.5 507.3 553.9 269.9 823.8
1982 620.2 160.9 52.4 4.6 339.2 499.0 564.3 273.9 838.1
1983 568.6 151.0 58.3 4.1 300.4 481.7 507.4 274.7 782.1
1984 649.5 179.2 63.1 4.2 352.1 543.9 587.6 308.3 895.9
1985 613.9 192.7 72.4 4.7 350.8 532.8 558.7 324.9 883.6
1986 620.1 189.6 76.4 4.3 360.4 529.9 564.4 325.9 890.3
1987 636.6 200.2 78.4 3.6 372.9 545.9 581.9 336.8 918.8
1988 638.1 223.5 85.1 3.6 382.2 568.1 579.6 370.7 950.3
1989 659.8 231.2 86.4 3.3 393.8 586.9 599.0 381.7 980.7
1990 693.2 244.3 88.1 3.5 424.5 604.5 630.2 398.9 1,029.1
1991 650.7 255.3 86.5 3.4 407.2 588.8 591.3 404.7 996.0
1992 651.8 252.2 90.1 3.5 407.2 590.3 588.6 409.0 997.5
1993 576.7 274.9 89.5 4.3 351.1 594.4 516.2 429.2 945.4
1994 640.3 300.5 88.1 4.6 399.1 634.4 566.3 467.2 1,033.5
1995 613.8 328.0 86.5 4.7 396.2 636.7 544.2 488.7 1,033.0
1996 630.7 340.3 88.1 4.8 409.8 654.0 563.7 500.2 1,063.9
1997 653.8 345.1 86.3 4.7 420.7 669.3 579.4 510.6 1,089.9
1998 640.6 385.9 85.8 5.3 417.7 699.8 570.6 547.0 1,117.5
1999 601.7 406.7 87.2 4.8 391.8 708.6 529.6 570.8 1,100.4
2000 574.3 409.2 85.6 4.6 373.7 700.0 507.5 566.1 1,073.6
2001 611.3 434.4 80.0 11.9 380.6 1747.1 1528.8 1598.9 11,127.7
2002 R572.1 R438.4 R82.5 R1.4 R357.4 R736.9 R492.9 601.4 R1,094.3
2003 E559.2 E428.4 E80.6 E1.3 E351.2 E718.3 E468.2 E601.3 P1,069.5
  • Lignite, the lowest ranked coal, is brownish-black in color and has a high moisture content. It tends to disintegrate when exposed to weather. Lignite is used mainly to generate electricity and contains about 9 to 17 million Btu per ton. Lignite has an ignition temperature of approximately 600 degrees Fahrenheit. Most lignite is mined in North Dakota, Montana, Texas, California, and Louisiana. (See Figure 4.1.)

Bituminous coal accounts for the largest share of all coal production; sub bituminous is second. (See Table 4.1.) In 2003 production of all types of coal totaled nearly 1.1 billion short tons. (A short ton of coal is 2,000 pounds.) Of that, nearly 1 billion short tons (92%) were bituminous and sub bituminous coal. Lignite and anthracite accounted for the remainder.

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