EQT Corp. has paid a $294,000 fine for inadvertently drilling into an abandoned coal mine during the construction of a water line for unconventional natural gas development in southwest Pennsylvania, according to the state Department of Environmental Protection (DEP). The incident caused four million gallons of abandoned mine drainage to leak into a nearby river and wetlands in violation of the Clean Streams Laws. DEP said that while EQT knew of abandoned mines in the area, it relied only on regional mapping and conducted no “further investigation.” EQT has implemented procedures to prevent such an incident from happening again and corrected the violations, which occurred in Allegheny County.