CHARLESTON, W.Va. -- Before the Upper Big Branch Mine disaster, federal regulators approved a new mining plan for Massey Energy that significantly weakened ventilation requirements meant to control explosive methane and coal dust, members of an internal U.S. Mine Safety and Health Administration review team have confirmed.The new mining plan was approved in June 2009, and set up the methane- and dust-control standards Massey was to follow in a longwall mining section where the April 5, 2010, explosion that killed 29 miners occurred.MSHA approved Massey's proposal to cut by more than half the fresh air the company was required to direct toward the working face of the longwall mining section at Upper Big Branch.And compared to Upper Big Branch's previous longwall plan, approved three years earlier, the latest MSHA approval required fewer dust-control water sprays and weakened language for how those sprays would be operated.Details of the MSHA action, contained in the agency's internal review report made public Monday, paint a more troubling picture than earlier information about the issue provided in April 2011 to the families of the miners who died in the worst U.S. coal-mining disaster in nearly 40 years.The internal review not only makes it clear that MSHA took no steps to avoid a repeat of previous methane incidents at Upper Big Branch in 1997, 2003 and 2004, but also indicates agency officials approved a new longwall plan without bothering to first compare Massey's proposal to the previous requirements."When you think about what the ventilation plan is there to prevent, and then they do this, it is just incredible," said longtime mine safety advocate Davitt McAteer, who led an independent team that investigated Upper Big Branch and questioned MSHA's enforcement of safety standards at the operation.Members of MSHA's internal review team concluded that none of the agency's missteps "caused the explosion," and top agency officials have promised a long list of reforms, including many measures they said they've already taken."MSHA is responsible for its actions and will address each of the problems the team has specifically identified," said Joe Main, assistant Labor secretary in charge of MSHA. "We take the deficiencies and recommendations outlined in this internal review extremely seriously."Problems with MSHA's review of mine operator plans for ventilation and roof control at underground mines has been an issue over and over following previous mining disasters.Internal reviews and other audits criticized MSHA's plan reviews following the deaths of 13 miners at the Jim Walter No. 5 Mine in Brookwood, Ala., the deaths of two miners in a fire at Massey's Aracoma Mine in 2006, and the deaths of six miners and three rescuers in a mine collapse at Crandall Canyon, Utah, in 2007.At Upper Big Branch, the longwall mining plan in question was put into place in late 2009, when Massey brought a longwall mining machine back after temporarily moving the machine to another one of its operations.Shortly after the one-year anniversary of the fatal explosion, families of the Upper Big Branch miners were told that MSHA had discovered it approved a reduction in the required air flow to the longwall section's working face from 60,000 cubic feet per minute under the earlier plan to 40,000 cubic feet per minute in Massey's new proposal. At the time, MSHA confirmed that information, but declined to discuss the matter in more detail until the internal review was complete.In a report released Tuesday, internal review team members said they had compared the earlier longwall plan from 2006 with the new one MSHA approved in June 2009. They found that MSHA had actually approved Massey's request to reduce the air-flow to the longwall face from 104,000 cubic feet per minute to 40,000 cubic feet per minute -- a far larger reduction that the disaster victims' families had been told. The 40,000 cubic feet per minute included in the approved plan is greater than the 30,000 cubic feet per minute minimum required by federal law. MSHA may require more ventilation if it is needed to protect miners at any specific operation.The MSHA internal review report said the new longwall plan at Upper Big Branch "was significantly less stringent," than the previous one, and said 40,000 cubic feet per minute of ventilation was "not sufficient to control respirable coal dust and mitigate methane outbursts at the mine." An appendix buried in the report listed at least 20 procedures that were "either relaxed or omitted," including fewer water sprays to control methane and dust and less specific mandates for how dust-control measures would work in the longwall section of the mine.Internal review team members did not specifically say these changes had anything to do with the explosion, but MSHA's own investigation team said inadequate ventilation and insufficient water sprays on the longwall machine were major contributing factors in the disaster.The internal review team said MSHA did not have procedures in places to ensure that previous mining plans -- let alone serious accidents -- were considered when new mining plan proposals were being reviewed by the agency.The team's report also blamed turnover among the supervisors and technical staff at MSHA's district office in Southern West Virginia.When the earlier longwall plan was reviewed, MSHA's district ventilation supervisor was Bill Ross. Ross left the agency in 2008, before the new plan was proposed, and took a job handling ventilation matters for Massey at Upper Big Branch and other local mines.Internal review team members concluded that Ross' replacement at MSHA, Joe Mackowiak, was not aware of the previous methane incidents at Upper Big Branch when the new longwall plan was reviewed and approved.The internal review report said that, after the explosion, documents about the earlier incidents "were not readily available" in MSHA files and were found packed in a box that Ross left behind when he went to work for Massey.Ross asserted his Fifth Amendment right and refused to answer questions from disaster investigators. An MSHA lawyer blocked McAteer's internal review team from pursuing questions regarding what MSHA officials knew about the earlier methane incidents.The internal review indicates that at least one local MSHA official, assistant district manager for technical programs Rich Kline, a 15-year-veteran of the agency, knew about the earlier methane incidents, and other MSHA records show Kline signed off on the new Upper Big Branch longwall plan.MSHA records also show that Lincoln Selfe, a 20-year-MSHA veteran, signed off on the new longwall plan, as well.Reach Ken Ward Jr. at firstname.lastname@example.org or 304-348-1702.