Two-leg longwall shield mechanics
By: by Thomas M. Barczak and David E. Schwemmer.
Contributors: Schwemmer, David E.
Series: Report of investigations (United States. Bureau of Mines) -- 9220.
Publisher: Dept. of the Interior
Published: 1989
Place of publication: Washington, DC
Language: eng
Number of pages: 34
Subjects: Mine roof control.; Longwall mining.
Notes:  88600305  t_oclc

Bibliogr.

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