Vertical magnetic noise in the voice frequency band within and above coal mines

Author:	Durkin, John.
Year:	1983
Document Type:	BMRA
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.23:8828.
Series:	Report of investigations / Bureau of Mines ;
Report Number:	8828
Subjects:	Voice frequency
	Coal mines and mining--Communication systems
	Electromagnetic noise
Link:	https://hdl.handle.net/2027/mdp.39015078469262