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Mining Publication: One-Way Fire Warning Alarm System for Underground Mines

NOTE: This page is archived for historical purposes and is no longer being maintained or updated. Contact NIOSH Mining if you need an accessible version.

Original creation date: July 1990

Image of publication One-Way Fire Warning Alarm System for Underground Mines

An ideal fire warning alarm system for underground mines would be low cost, convenient, fast, reliable, and able to warn all underground workers. Present warning systems, such as phones, messengers, and stench, fail one or more of these criteria. The U.S. Bureau of Mines may have devised the ideal system. The one way communication system employs a large loop antenna and transmitter to create a 630 hertz (Hz) electromagnetic field to send information through-the-earth to cap lamp battery mounted micro-receivers worn by underground miners. Field tests of prototype equipment in 1986 resulted in through-the-rock signal transmission of over 762 m (2500 ft). Subsequent hardware upgrades for more recent tests resulted in transmissions of over one mile. Recently developed receiver circuitry employs phase-locked-loop detection circuitry responsive only to a specific series of pulses of given time duration, that eliminates false alarms from electromagnetic noise emitted by mine equipment, power lines, or lightning. A multichannel system can relay standard messages to miners.

Authors: KE Hjelmstad, MA Ackerson

Conference Paper - July 1990

The Tenth WVU International Mining Electrotechnology Conference, Morgantown, West Virginia, July 24-27, 1990; :47-52