Ultrasonic convergence measurements
By: by James R. McVey.
Series: Report of investigations ;; 8893; Report of investigations (United States. Bureau of Mines) ;; 8893.
Publisher: U.S. Dept. of the Interior, Bureau of Mines
Published: 1984
Place of publication: Pittsburgh, PA
Language: eng
Number of pages: 11
Subjects: Coal mines and mining -- Safety measures -- Equipment and supplies.; Mine roof control.; Ultrasonic testing.