Propagation of EM Signals in Underground Metal/Non-Metal Mines

摘要

The report describes the results of a measurement and analysis program to characterize wireless radio transmission in metal-nonmetal mines over a wide frequency range from 0.2 to 1,000 MHz and over a variety of mine environments. Six mines were chosen based on the relative economic significance of their product to the U.S. economy. Mine types include oil shale, uranium, potash, lead-zinc, copper, and silver. Particular mines were chosen to embody the most important mining techniques of the group. The results show that transmission at medium frequencies are optimum for wireless mine communications, in agreement with extensive testing previously performed in coal mines, and that minewide wireless systems are feasible with a minimum requirement for new dedicated wiring. At least one need for such a wireless system was identified in each mine visited.