CHARLESTON, W.Va. -- Shortly before noon on Feb. 18, 2004, workers deep inside Massey Energy's Upper Big Branch Mine heard a "big thump." The mine floor opened up, creating a 240-foot-long fracture that sent methane gas pouring into the mine.
No one was injured. But it wasn't the first time such an incident, known as a "methane outburst" occurred at the Raleigh County mine.
Less than a year before, on July 3, 2003, Massey had reported that Upper Big Branch became inundated with methane after an "extreme bump" and heaving of the mine floor.
"Mine personnel described the July 2003 outburst as a very high pressure event, comparable to the sound of a jet engine," according to an internal U.S. Mine Safety and Health Administration report on the incident.
Federal regulators concluded at the time that a reservoir of natural gas below the Upper Big Branch Mine might easily be released into the active mining operation. They recommended a series of steps to try to prevent such incidents, or at least to control them, hopefully preventing an explosion or fire. One such recommendation -- to drill "degasification" wells into the mine -- was among the steps Massey Energy President Don Blankenship argued this week was the wrong approach for ventilating Upper Big Branch.
MSHA documents describing the 2003 and 2004 incidents, obtained this week by The Charleston Gazette, are being closely reviewed by government teams who are investigating the Upper Big Branch Mine Disaster. Investigators are also trying to find additional records that might explain what actions were taken by MSHA and Massey after the incidents.
"That is a good question, and it's a question I've asked our investigators," said Ron Wooten, director of the state Office of Miners Health, Safety and Training. "Were the recommendations put in place? What was done? Those are the questions that need to be answered."
Jesse Lawder, a spokesman for MSHA, said the agency would not comment on the 2003 and 2004 incidents or on what actions it required Massey to take afterward.
Twenty-nine miners died and two others were injured in an April 5 Upper Big Branch explosion, which investigators believe involved an ignition of methane gas made far worse by a buildup of highly explosive coal dust.
MSHA and the state are conducting closed-door interviews of government inspectors, Massey workers and company officials as they continue their probe into the worst U.S. coal-mining disaster in 40 years. While former Upper Big Branch miners and the families of some of the disaster victims are speaking out about safety problems at the mine, government officials will say little publicly about what they are learning in their investigation.
While Massey has publicly said air quality in the mine was good just prior to the explosion, government inspection reports include repeated violations for poor airflow, ignoring mandated ventilation requirements, broken methane monitors and other problems that could play a role in an explosion or fire.
And investigators are now concerned that the previous methane outbursts could provide one possible explanation for where the explosive gases came from that ignited the April 5 explosion.
Methane is released naturally from coal seams during the mining process, and is a constant threat in underground coal operations. Federal law requires all mines to operate according to MSHA-approved ventilation plans intended to sweep fresh air through a mine, and keep coal dust and methane below explosive levels. Ventilation plans include requirements for large fans and a series of walls, curtains and other devices to direct fresh and dirty air in and out of underground tunnels.
The 2003 and 2004 methane outbursts occurred as Massey's Performance Coal Co. was mining different "panels" of coal with its advanced longwall mining machine. But both incidents occurred as the company continued to mine -- as it was still doing prior to the April explosion -- in a coal vein known as the Eagle Seam.