http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Basic estimated capital investment and operating costs for underground bituminous coal mines
mines with annual production of 1.06 to 4.99 million tons from a 72-inch coalbed
2 unnumbered pages, ii, 41 pages : diagram ; 26 cm.
by Sidney Katell, E. L. Hemingway, and L. H. Berkshire : Process Evaluation Group--MMRD.
Information circular (United States. Bureau of Mines) ; 8682A