Mechanical mining in some bituminous-coal mines
Subtitle: progress report 6, extraction of pillars with mechanized equipment
By: by Wilbur A. Haler ... [et al.].
Contributors: Haley, Wilbur A.
Series: Information circular (United States. Bureau of Mines) -- 7631
Publisher: U.S. Dept. of the Interior, Bureau of Mines
Published: 1952
Place of publication: Washington, DC
Language: eng
Number of pages: 63
Subjects: Coal mines and mining -- United States.; Coal-mining machinery.
Notes: 1