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.