Coal resource classification system of the U.S. Bureau of Mines and U.S. Geological Survey / a report published jointly by the U.S. Bureau of Mines and U.S. Geological Survey.
Publication Info.
[Washington, D.C.] : U.S. Bureau of Mines : U.S. Geological Survey, 1976.
Washington : United States Government Printing Office
Mode of access: Internet from the USGS Web site. Address as of 6/30/04: http://pubs.usgs.gov/bul/b1450b/index.htm; current access is available via PURL.
Note
Title from HTML title screen (viewed June 30, 2004).
"Definitions of coal resource classification terms used by the U.S. Bureau of Mines and U.S. Geological Survey."