CHARLESTON, W.Va. -- A project using sensors to detect underground pockets of water could help solve the problem of mapping abandoned coal mines.
Originally developed to help combat acid mine drainage, the project could help miners avoid accidents similar to that at the Quecreek Mine in Somerset County. Nine miners in July were trapped there for days after digging into a flooded abandoned mine that had been improperly mapped.
Terry Ackman, team leader for the National Energy Technology Laboratory project, said early test results look promising. The project mapped an area in Kettle Creek, Pa., that was mined in the mid- to late-1800s.
The project used a helicopter to fly a torpedo-shaped sensor over the 50-square-mile area. Using data collected by the sensor, teams then confirmed and sampled all places where underground water was reaching the surface.
In a week, the project had a map that otherwise would have taken years to develop, Ackman said.
"Needless to say, whatever mapping is available is very sparse and poor," Ackman said. "I might not be able to tell you the boundaries of the abandoned mine, but it looks like we're going to be able to tell you where the water is."
Terry Farley, an administrator for the state Office of Miners' Health, Safety and Training, said discovering underground pockets of water would be a big step toward safer mining.
Mining companies and various states now use existing mine maps and horizontal drilling to detect underground water pockets.
The acid mine drainage project uses electromagnetic waves that penetrate the ground to about 300 feet. The waves interact with conductive elements to create eddy currents read by the sensor.
While pure water has an almost undetectable conductivity, most underground water contains metals or other impurities that make it more conductive.
Ackman said one goal of the project is to come up with a "cookbook" that would allow private industry and government agencies to reliably process sensor data.
The project is also gearing up to test another sensor system that could find water at levels five times as deep.
That method aims to use a varying magnetic field to induce electrical currents in underground conductive materials.
Along with Virginia mining officials and the U.S. Office of Surface Mining, the laboratory has picked sites to test three scenarios: acid mine drainage problems; a Quecreek scenario where an abandoned mine is near an active mine; and conditions similar to the Martin County, Ky., coal slurry spill, where a coal waste pond collapsed into an abandoned mine beneath it and dumped millions of gallons of slurry into adjacent streams.
