Through-the-Earth, Two-Way, Mine Emergency, Voice Communication Systems

Recent mine tragedies have focused attention on wireless mine emergency communication systems that will function in a post disaster environment. Wireless, through-the-earth, voice communication systems have been developed based on propagation characteristics of very low frequency radio signals operating between 3000 and 8000 Hz. These radio frequencies have been demonstrated in a real-time voice communication system to propagate through the earth. This paper discusses in-mine testing of a prototype through-the-earth, two-way voice communication system. The limitations imposed by overburden depth, electromagnetic interference and permissibility requirements are presented