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Determination of the Electromagnetic Environment in Coal Mines.

Authors
Crary-JH
Source
NTIS: PB/213-204 Available for Reference At Bureau Libraries :139 pages
Link
NIOSHTIC No.
10001480
Abstract
This report concerns the need for improved communication during and following mine disasters, especially when miners are trapped. A reliable and versatile communication system throughout an entire mine could be adapted to automatic monitoring at a central location of important environmental parameters, such as air temperature, composition, pressure, seismic activity and so forth, throughout the mine. The use of long-wave electromagnetic methods appears to solve the problems. Basic information required consists of (1) a knowledge of the magnitude of frequency both above and below the surface, (2) information on the attenuation of em signals propagating from surface to subsurface points, and vice versa, and the antenna coupling characteristics which would be involved, and (3) a knowledge of the accuracy with which an underground signal source can be located from the surface and vice versa. The report covers noise environment, attenuation and antenna coupling, determination of optimum frequencies, electromagnetic location, and properties of tunnels as high frequency waveguides.
Publication Date
19720101
Document Type
CP; Final Contract Report;
Fiscal Year
1972
NTIS Accession No.
PB-213204
NTIS Price
A08
Identifying No.
OFR 35-72
NIOSH Division
DRC;
Source Name
NTIS: PB/213-204; Available for Reference At Bureau Libraries
Performing Organization
National Bureau of Standards
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