New signaling device for shaft mines with comments and suggested modifications.

Bibliographic Details

Other Authors:	Potter, Elmer Vernon, 1908-, Stewart, L. D.
Format:	Government Document eBook
Language:	English
Published:	Washington, D.C. : [publisher not identified], 1931.
Series:	Mines Bur. Info. Circ. No. 6487
Subjects:	Signals and signaling. Electronic books.
Online Access:	Connect to the full text of this electronic document