It’s a project that stems from the Sago mine disaster, an explosion which trapped 13 miners for nearly two days in January 2006 in Upshur County, W.Va. The miners were trapped 2 miles inside the mine at about 280 ft below the ground. The sole survivor later recounted how he and his fellow miners took turns pounding on roof bolts and bearing plates underground with a sledgehammer, in hopes that rescuers above ground would hear those pleas for help.
“No one heard them,” Heasley said. “It’s all hindsight and conjecture, but if they had a system like the one we’re developing, there may have been a quicker effort getting to them. It would’ve changed the dynamic of the situation.”
Several factors inhibited responders’ ability to locate and rescue the trapped miners. Traditional seismic systems used to locate trapped miners are limited in depth, Heasley explained. Most systems can’t locate miners more than 400 ft underground. Although the Sago miners were trapped within 280 feet, background noise interfered with the signals from the seismic system.
Heasley said background noise, which can be anything from the wind, chatter or trees rustling, can interfere with the signals that determine a miner’s exact location. “You can have rain, road traffic, rescuers drilling…there’s a number of things that can impede the signals,” he said.
But this system in development filters out the background noise. Last year, Heasley began collaborating with SureWave Technology, a U.K.-based company, to further develop this seismic system. Since then, they’ve conducted field tests at two mine sites: The 4 West mine in Greene County, Pa., and the Federal No. 2 mine in Fairview, W.Va. With the aid of his graduate students and other mining engineering faculty, Heasley and SureWave successfully detected the location of individuals pounding with sledgehammers 800 ft below ground. “We’re proposing to test this system up to 2,000 ft below ground, which would take care of 99% of mines in this country,” Heasley said.
The system consists geophones attached to a computer that uses an algorithm to filter out background noise and determine a precise location of the underground sound. The rescue response team should know within hours whether or not there are survivors from the accident and, crucially, where they are located. Heasley and SureWave will continue to test this system at mines over the next 15 months—the duration of the grant. They hope to test it at a western U.S. deep mine, as well as a site with background noise in West Virginia.