Longer-than-seam-height drill development program
By: by G. K. Derby and J. E. Bevan.
Contributors: Bevan, John E , joint author.; United States. Bureau of Mines.
Series: Report of investigations - Bureau of Mines ; 8273; Report of investigations (United States. Bureau of Mines) -- 8273.
Publisher: Dept. of the Interior, Bureau of Mines
Published: 1978
Place of publication: [Washington]
Language: eng
Number of pages: 16
Subjects: Boring.; Mine roof bolting.