What’s more, areas of a mine where mining is finished and have been sealed off, but which still contain significant amounts of coal, coal dust, and methane, are often not monitored directly. These areas can be particularly dangerous because, unlike many pristine coal seams, the coal here has been exposed to oxygen, and so is vulnerable to combustion. Because of these dangers, electronic sensors aren’t allowed in sealed areas–they could cause a spark that sets off an explosion. But techniques have been developed to monitor inside sealed areas continuously by sampling gas levels via tubes that run to the surface–a practice used in Australia, but not much in the U.S., Grubb says.
The best way to avoid flooding is to probe ahead of the mining face, says Jeff Kohler, the mine safety research director at the National Institute for Occupational Safety and Health. His conclusion came after studying an incident at Quecreek Mine in Pennsylvania, where nine miners were trapped by water in 2002.
Researchers at Virginia Tech are developing a system that uses multiple trace gases to probe the complex ventilation systems of mines. They’re working to identify safe gases that can be injected at different entry points to the mine, and then measured at exists and ventilation shafts. Based on the relative concentrations of the gases, the amount of time it takes them to move from entrances to exits, and measurements of the ventilation system before an accident, it could prove possible to use computer models to locate obstructions, which could help rescuers, says Kray Luxbacher, professor of mining and minerals engineering at Virginia Tech.
Improving communications to locate miners will be difficult. In existing systems, wireless mesh networks can allow mine operators to track the location of miners, but these rely on wires to relay the signal out of the mine. In a disaster, such communications are often cut.
Experts emphasize, however, that new technology isn’t necessary to avoiding mining disasters– just following current regulations consistently could make a big improvement in mine safety. “Technology is wonderful, but it’s merely a tool. It still takes people to make it work, or not work,” Tien says.