Federal and state investigators also are looking into concerns the airlock doors used to channel airflow underground were frequently left open or didn't fit properly, allowing fresh air to inadvertently be directed away from the longwall area.
Top MSHA officials have said Massey used such doors, instead of other ventilation control systems, more frequently than other mine operators. MSHA said the doors technically met legal requirements, so agency officials had no choice but to approve them. MSHA officials say they prefer "overcasts," which are enclosed airways that permit two air currents to pass by one another uninterrupted.
"Doors are easier and cheaper to construct than overcasts, but they can completely rob the working sections of air when they are left opened," MSHA deputy assistant secretary Greg Wagner wrote in a July 2010 memo critical of Massey's ventilation practices.
Wagner's memo also said that Massey had proposed a ventilation change to direct about 60,000 cubic feet per minute of air from the longwall area to a new set of mining tunnels located off the tail end of the longwall area. That request was being reviewed by MSHA when the disaster occurred.
In the months prior to the disaster, MSHA and state inspectors repeatedly cited Massey for a variety of serious ventilation violations at Upper Big Branch, and officials say the company was having a difficult time resolving airflow problems on a mine-wide basis.
But the news that MSHA approved a reduction in required airflow at the Upper Big Branch longwall also adds to questions about the federal agency's actions at the mine prior to the explosion.
"With the longwall being brought back to the same general position or location, it raises questions about why you would support a dramatic change in the ventilation," said Davitt McAteer, who ran MSHA during the Clinton administration and was appointed by former Gov. Joe Manchin to perform an independent investigation at Upper Big Branch.
MSHA officials did not invite McAteer to Tuesday night's meeting, for the first time excluding the independent team and other state investigators from a briefing for the Upper Big Branch families.
And on Wednesday, MSHA officials excluded McAteer from a briefing on the preliminary findings of the agency's internal review of its own performance prior to the disaster.
MSHA has been criticized before, after previous mine disasters, for not being rigorous enough in its review and approval of mine ventilation and roof control plans submitted by mine operators.
After 13 miners died at the Jim Walter Resources No. 5 Mine in Brookwood, Ala., in September 2001, an internal review team criticized the local MSHA office's handling of mining plans at that operation. Also, a U.S. Government Accountability Office report said weaknesses in plan reviews were a more widespread MSHA problem.
And after the Crandall Canyon Disaster in Utah in 2007, a Labor Department inspector general's investigation said MSHA was not thorough enough in reviewing the roof control plan for the mine where a major collapse killed six miners and three rescue workers.
Reach Ken Ward Jr. at kw...@wvgazette.com or 304-348-1702.