CHARLESTON, W.Va. -- Questions are piling up about the failures of federal regulators to prevent the worst U.S. coal-mining disaster in nearly 40 years, but an "internal review" of Department of Labor enforcement at the Upper Big Branch Mine is still a work in progress.

U.S. Mine Safety and Health Administration officials have said it will be several months before a report on their internal review is completed, and MSHA has declined to say more about progress by the review team.

MSHA also has announced that any timeline for an examination of that internal review promised by Labor Secretary Hilda Solis would be performed by an independent team of mine-safety experts.

If MSHA chief Joe Main is upset about any information he's been given about his agency's failings at Upper Big Branch, he's not saying so publicly.

When asked about the internal review, Main has noted that such reviews following previous mine disasters found problems, and he doesn't think anyone should expect the findings at Upper Big Branch to be any different.

"[In] Every internal review, you're going to find that the agency was not perfect," Main said at a media briefing in June. "I don't think you're ever going to find that the agency was perfect.

"Nobody should expect a perfect report card," Main said. "It's never happened."

However, the stakes in the Upper Big Branch review have increased greatly since the release in early December of the report by the MSHA team investigating the causes of the April 5, 2010, explosion that killed 29 miners.

In its report, the MSHA team concluded that methane leaking from the Upper Big Branch Mine's floor helped ignite the deadly explosion, and that Massey's failure to follow previous MSHA recommendations on controlling such leaks was a contributing cause of the disaster.

MSHA officials have admitted, though, that the agency never took steps to ensure Massey implemented those recommendations following previous methane incidents in 1997, 2003 and 2004 at Upper Big Branch. Also, MSHA revealed in a letter to Congress that agency officials aren't even sure they ever gave Massey a written report on those recommendations.

House Education and Workforce Chairman John Kline, R-Minn., has been pressing MSHA for answers about the previous methane incidents and the agency's failure to properly follow up on them.

U.S. Mine Safety and Health Administration officials have said it will be several months before a report on their internal review is completed, and MSHA has declined to say more about progress by the review team.

MSHA also has announced that any timeline for an examination of that internal review promised by Labor Secretary Hilda Solis would be performed by an independent team of mine-safety experts.

If MSHA chief Joe Main is upset about any information he's been given about his agency's failings at Upper Big Branch, he's not saying so publicly.

When asked about the internal review, Main has noted that such reviews following previous mine disasters found problems, and he doesn't think anyone should expect the findings at Upper Big Branch to be any different.

"[In] Every internal review, you're going to find that the agency was not perfect," Main said at a media briefing in June. "I don't think you're ever going to find that the agency was perfect.

"Nobody should expect a perfect report card," Main said. "It's never happened."

However, the stakes in the Upper Big Branch review have increased greatly since the release in early December of the report by the MSHA team investigating the causes of the April 5, 2010, explosion that killed 29 miners.

In its report, the MSHA team concluded that methane leaking from the Upper Big Branch Mine's floor helped ignite the deadly explosion, and that Massey's failure to follow previous MSHA recommendations on controlling such leaks was a contributing cause of the disaster.

MSHA officials have admitted, though, that the agency never took steps to ensure Massey implemented those recommendations following previous methane incidents in 1997, 2003 and 2004 at Upper Big Branch. Also, MSHA revealed in a letter to Congress that agency officials aren't even sure they ever gave Massey a written report on those recommendations.

House Education and Workforce Chairman John Kline, R-Minn., has been pressing MSHA for answers about the previous methane incidents and the agency's failure to properly follow up on them.

"The families of the Upper Big Branch miners deserve the whole story of what went wrong," Kline said. "If MSHA failed to act on critical information that may have improved the safety of those miners, the people of West Virginia deserve to know why."

The methane recommendations are just one of the issues MSHA officials have pointed to as being examined by the internal review team. Among the others:

Reach Ken Ward Jr. at kw...@wvgazette.com or 304-348-1702.