CHARLESTON, W.Va. -- Internal investigators at the U.S. Mine Safety and Health Administration are trying to sort out why agency officials approved a major reduction in the required airflow at Massey Energy's Upper Big Branch Mine, months before the April 2010 explosion that killed 29 miners.
MSHA officials discussed the matter publicly for the first time Wednesday, after disclosing the ventilation change issue during a private meeting Tuesday night with families of some of the miners who died in the disaster.
"That's something that the internal review is looking at to find out why," Kevin Stricklin, MSHA's coal administrator, told the Gazette. "I understand why people are concerned about that, and we want to get to the bottom of that."
The change in required airflow occurred when Massey returned an advanced longwall mining machine to the Upper Big Branch Mine in late 2009. The machine had been moved to another Massey operation for several years.
In the coal industry, mine operators must use powerful fans and collections of specially located walls, doors and other devices to channel large amounts of fresh air through mazes of underground tunnels. Proper mine ventilation is key to preventing black lung disease and to preventing the buildup of explosive methane gas and coal dust.
Generally, federal regulations require a minimum of 30,000 cubic feet per minute of fresh air flowing into a longwall mining face area. The rules allow MSHA to require more ventilation than that on a site-specific basis.
When the longwall machine was previously in use at Upper Big Branch, Massey's Performance Coal Co. was required to maintain at least 60,000 cubic feet per minute of fresh air running to the longwall.
But when the longwall machine was returned to the mine, MSHA in August 2009 approved the company's request to reduce the minimum airflow required to 40,000 cubic feet per minute, Stricklin confirmed Wednesday.
It's not clear what role -- if any -- the change in minimum required airflow could have had in the fatal explosion, which officials believe involved a methane ignition made far worse by a buildup of explosive coal dust underground.
At about 2:40 p.m. on April 5, a little more than 20 minutes before the explosion, airflow to the longwall was recorded at 56,000 cubic feet per minute -- well above the amount required by the MSHA-approved plan.
Still, Stricklin noted that MSHA investigators are looking closely at why airflow to the longwall had dropped substantially -- from more than 100,000 cubic feet per minute to 50,000 -- in the month or so immediately prior to the explosion.
Stricklin said Tuesday that MSHA believes the drop could have been caused by Massey's addition of a third "development section." Mining there was preparing the underground tunnels for the next area where the longwall would mine. Massey added it when roof and flooding conditions in another development section the company had planned to use next turned out to be too dangerous.