Modified Longwall Mining with A German Coal Planer (Plow) in the Pocahontas no. 4 Coal Bed, Helen, W. va.
Contributors: Haley, W.; Dowd, J.; Turnbull, L.
Series: Report of investigations (United States. Bureau of Mines) -- 4922
Publisher: s.n
Published: 1953
Place of publication: S.l
Language: eng
Notes: 1