Some signaling systems in metal-mine shafts.

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Bibliographic Details
Online Access:	Full Text (via ProQuest)
Corporate Author:	United States. Bureau of Mines
Format:	Government Document eBook
Language:	English
Published:	[Washington] : [s.n.], 1939.
Subjects:	Mineral industries. Mine accidents. Electric machinery.

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Full Text (via ProQuest)

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Call Number:	I28.27..7083
I28.27..7083	Available