flexible helical rock bolt
By: by Clarence O. Babcock.
Contributors: United States. Bureau of Mines.
Series: Report of investigations - Bureau of Mines ; 8300; Report of investigations (United States. Bureau of Mines) -- 8300.
Publisher: Dept. of the Interior, Bureau of Mines
Published: 1978
Place of publication: [Pittsburgh, Pa.]
Language: eng
Number of pages: 26
Subjects: Rock bolts.
Notes: Bibliography: p. 24.