Through Earth Communications

Through earth communications is realised using the PED® Communication System which is based on ultra-low frequency transmission that propagates through rock strata. In South African conditions this has been demonstrated at 1400 meters. The PED® System has been in use at mines for over fifteen years and remains the only proven through-the-earth (TTE) communication system in use at mines. Refinements to the system over this time have further improved its reliability and functionality. It has been installed in over one hundred & fifty coal and metalliferous mines in Australia, USA, Canada, China and Sweden.

PED® is a one way communication system providing mine wide signal coverage. It can be used for emergency communication, remote switching of fixed plant equipment such as fans and pumps, and can be used for centralized blasting. The ability of PED® to transmit through rock strata means it can truly deliver complete signal coverage to an underground mine. This is achieved without the need of installing antenna cable in every part of the mine (something more traditional ‘line-of-sight’ radio systems would require). A relatively small antenna on the surface, or underground, provides complete signal. This signal coverage is achieved at a fraction of the cost than any other type of radio system. Where other systems are vulnerable to rock fall, fire and general wear and tear, PED® greatly reduces these typical problems of unreliability and maintenance. The ULF (ultra low frequency) transmission system transmits to a number of receiver types to allow a range of applications. Messages can be sent to receivers carried by miners (ICCL), or to display units mounted in vehicles (AutoPED). The PED® Communication System can also be used to remotely control equipment like fans and pumps (ControlPED), or for the remote initiation or firing of blasts.