The incident, classified as an outburst, occurred at about 8:30 p.m. May 12 at the Brody No. 1 operation in rural Boone County.

West Virginia Office of Miners’ Health Safety and Training spokeswoman Leslie Fitzwater Smithson confirmed the workers as Eric Legg, 48, and Gary Hensley, 46. No other injuries were reported, and an investigation has commenced.

The incident is the first multiple coal fatality in U.S. coal since a roof fall at the Dotiki mine in Webster County, Kentucky., on April 28, 2010.

Brody was a contract mining operation of Black Stallion Coal Company prior to its affiliation with Patriot Coal, which has so far not made comment on the incident.

The mine has also been the target of federal officials as of late; in October 2013, it was one of three mines which received a pattern of violations (POV) notice from MSHA.