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1. Electric blasting switches, underground mines, Lake Superior District.

Creator Personal:
Cash, Frank E. (Frank Errette), Petersen, Max S.
Title:
Electric blasting switches, underground mines, Lake Superior District.
Call Number:
P19460
Date:
1946
Description:

Serial issue. Issued as: United States. Bureau of Mines. Information circular, 7372 (1946:Sept.).

Subject Topical:
Mine safety--Lake States., Ground control (Mining)--Lake States., Iron mines and mining--Lake States--Safety measures.
All:
Ground control (Mining)--Lake States., Iron mines and mining--Lake States--Safety measures., Mine safety--Lake States.