Low Frequency Data communications for mine worker personal safety

Leikhim and Associates is very interested in the safety of mineworkers and is presently researching the viability
of a low frequency, low data rate bi-directional personal communications device for mineworkers. The goal is to
provide a miniaturized device, which will communicate directly through the overburden to an array of multiple
antennas located on the surface above. Through time and phase differential means, the approximate location
of an individual mineworker can be determined. 

The communications protocol will be necessarily slow but will provide for acknowledgement of communications and
bi-directional messaging between miner and a safety control center. Individual miners can be paged and an automatic
acknowledgement of location be received at the safety control center. This two-way capability will provide trapped miners
assurance that help is coming and will aid in coordinating rescue.

The next phase of this project will be the construction of prototype proof of performance equipment to deploy under operational