Credit: University of Utah.
This diagram shows the layout of a system that University of Utah scientists developed to find miners trapped by mine cave-ins. The system was tested in a utility tunnel on campus, and at an abandoned copper mine near Tucson, Ariz. The diagram shows how sound receivers known as geophones are lined up on the ground surface above a mine tunnel. Each red star within the tunnel represents a "base station" comprised of a sledgehammer and an iron plate bolted to the mine wall. In the event of a mine collapse, the miners try to reach the nearest base station, where they use the sledgehammer to bang on the iron plate. The pattern of seismic waves "heard" by the geophones is analyzed in a computer to pinpoint the miners' location.