Propagation of radio waves in underground tunnels and underground radio systems

A typical potash mine consists of a network of interconnected straight tunnels with rectangular cross section located about 3000 feet underground. The tunnel system may be over 10 kilometers in length. A wireless system is needed to distribute video information, radio telephony and digital control information within the tunnel network. A program was initiated to obtain the propagation data which is needed to optimize system design. An experimental system named `distributed antenna system´ (DAS) was designed and installed in the Central Canada Potash facility. The DAS makes use of the unique propagation characteristics of the potash tunnel network and can be used in place of the more expensive leaky feeder system used in other mines