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COAL RESOURCE CLASSIFICATION SYSTEM OF THE U.S. BUREAU OF MINES AND U.S. GEOLOGICAL SURVEY

Mineral Resource Classification Systems of the U.S. Bureau of Mines and the U.S. Geological Survey

GEOLOGICAL SURVEY BULLETIN 1450-B

A report published jointly by the U.S. Bureau of Mines and U.S. Geological Survey. Definitions of coal resource classification terms used by the U.S. Bureau of Mines and U.S. Geological Survey.


Table 1.--Coal Resource/Reserve Criteria

  Depth, Feet (Metres) Thickness, Inches (Centimeters)
Total Resources and Undiscovered Resources    
Anthracite and bituminous coal 6,000 (1,800) 14 (35)
Subbituminous coal and lignite 6,000 (1,800) 30 (75)
Identified Resources.1    
Anthracite and bituminous coal 6,000 (1,800) 14 (35)
Subbituminoujs coal and lignite 6,000 (1,800) 30 (75)
Reserve Base.2    
Anthracite and bituminous coal 1,000 (300) 28 (70)
Subbituminous coal 1,000 (300) 60 (150)
Lignite 120 (40) 60 (150)
Reserves    

 

Criteria same as Reserve Base but with Recovery Factor applied.

Subeconomic Resources.3    
Anthracite and bituminous coal 0-1,000 (300) 14 (35)-28 (70)
  1,000 (300)-6,000 (1,800) 14 (35)
Subbituminous coal 0-1,000 (300) 30 (75)-60 (150)
  1,000 (300)-6,000 (1,800) 30 (75)
Lignite 0-120 (40) 30 (75)-60 (150)
  120 (40)-6,000 (1,800) 30 (75)

1Identified Resources are classified as Measured, Indicated, and Inferred according to the degree of geologic assurance as described in the text.
2The Reserve Base includes some beds that are thinner and/or deeper than the general criteria permit, but that presently are being mined or are judged to be mineable commercially at this time.
3Also includes currently nonrecoverable part of Reserve Base.


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