A new and more accurate method has been found to locate trapped survivors of underground mining in disaster situations. University of Utah researchers have developed a system thaIt involves bolting iron plates to the walls of tunnels at regular intervals and placing sledgehammers nearby. The idea is that, in the event of a collapse, survivors able to reach one of the plates would bash it to create vibrations that are detected by a string of geophones, standard devices used to measure seismic activity, placed on the surface along the line of the mine. <full article >