Electric blasting switches, underground mines, Lake Superior district

Author: Petersen, Max S.
Additional Authors: Cash, Frank E.
Year: 1946
Document Type: USBI
Issuing Agency: U.S. Dept. of the Interior, Bureau of Mines,
SUDOC: I 28.27:7372
Series: Information circular / United States Department of the Interior, Bureau of Mines ;
Report Number: 7372
Subjects: Mine safety--Lake States
Iron mines and mining--Lake States--Safety measures
Ground control (Mining)--Lake States
Link: https://hdl.handle.net/2027/mdp.39015078515445

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