After 13 miners were trapped in a coal mine in Sago, West Virginia, four years ago, rescuers didn’t know where to look for survivors — they could have been anywhere between 11,000 and 13,000 feet from the entrance. Radio waves can’t penetrate very far through rock, so there was no way to communicate with the miners.
A new system developed by Lockheed Martin aims to change that, by using magnetic waves to carry voice and text messages.
The MagneLink Magnetic Communication System works like a radio, but at extremely low frequencies. Unlike radio waves, magnetic energy can penetrate coal and rock, says Dave LeVan, the research engineer at Lockheed who developed the system.
It can connect to the short-wave radios miners use to communicate within mine shafts, but it has a much longer range and can reach the surface.