Determination of the Electromagnetic Environment in Coal Mines.

摘要

The report concerns the need for improved communications 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,etc.,throughout the mine. Use of longwave electromagnetic methods appears to solve these problems of communication. The report covers noise environment,attenuation and antenna coupling,determination of optimum frequencies,electromagnetic location,and properties of tunnels as high frequency waveguides. (Author)