"They were scheduled for those," Main answered. "As far as were they all completed, that's something that will be assessed."

In a prepared statement issued after the hearing, MSHA said agency officials have "found no evidence that we missed the timeframe for completing spot inspections at UBB, based on the procedures in place."

But, MSHA said, an "internal review team will examine MSHA records thoroughly to ensure that we have met those inspection requirements."

Under federal law, MSHA is required to conduct frequent spot inspections -- sometimes as frequently as every 5 days, depending on methane levels -- to check on potential ventilation problems at mines that liberate large amounts of the explosive gas.

Agency records indicate MSHA completed these required periodic spot inspections in January, February and March 2010.

The last spot inspection prior to the explosion was on March 25, and another spot inspection was not performed until April 12.

MSHA spokeswoman Amy Louviere said that the agency had Upper Big Branch on a schedule for spot inspections every 10 days from January through the end of March 2010. Sometime during that period, agency officials found higher levels of methane, and the mine's spot inspection frequency was to be increased to every five days starting April 1, Louviere said.

Louviere said that MSHA believes a new spot inspection was due to be conducted sometime between April 2 and April 6. The explosion occurred on April 5.

"We don't live in a perfect world," Main told lawmakers. "We wish that we did. With all of the pieces that we inspect, there are some quality improvements that we could make."

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

CHARLESTON, W.Va. -- Congressional Republicans grilled the nation's top mine safety official Thursday amid questions about whether the U.S. Mine Safety and Health Administration took tough enough enforcement actions prior to the Upper Big Branch Mine Disaster a year ago.

As the anniversary of the April 5, 2010, explosion approaches, MSHA chief Joe Main appeared at a hearing held by the Senate Committee on Health, Education, Labor and Pensions to update lawmakers on its investigation and stepped up enforcement efforts since the disaster that killed 29 miners.

The Obama administration and Democrats in Congress are pushing for new legislation to give MSHA additional enforcement tools, while Republicans generally oppose giving the agency new powers, especially when it's not clear that all existing authorities are being used.

"Some of the news coming out of the administration is not encouraging," said the committee's ranking Republican, Sen. Mike Enzi of Wyoming. "MSHA knew of problems at UBB and failed to use the full extent of its authority to fix those problems."

Enzi quizzed Main about a Gazette story that reported MSHA never used new legal authority to fine UBB up to $220,000 for "flagrant" safety violations.

GOP lawmakers also questioned Main about why MSHA hadn't yet made public a series of audits -- also revealed by the Gazette -- that examined enforcement lapses around the country in 2008 and 2009. He also asked about MSHA's refusal to release all agency records about methane accidents at Upper Big Branch in 2003 and 2004.

"The longer it takes for these documents to get out, the more it looks like MSHA knew more and could have done more to prevent this from happening," Enzi said.

Committee Chairman Tom Harkin, D-Iowa, praised Main for launching inspection "blitzes" at mines across the country and proposing rules aimed at eliminating deadly black lung disease.

"I am impressed that MSHA seems to have acted so quickly to fix the substantial problems that have often crippled the agency," Harkin said.

Enzi asked Main if his agency's record at Upper Big Branch included special spot inspections required for mines that liberate large amounts of explosive methane gas.

"They were scheduled for those," Main answered. "As far as were they all completed, that's something that will be assessed."

In a prepared statement issued after the hearing, MSHA said agency officials have "found no evidence that we missed the timeframe for completing spot inspections at UBB, based on the procedures in place."

But, MSHA said, an "internal review team will examine MSHA records thoroughly to ensure that we have met those inspection requirements."

Under federal law, MSHA is required to conduct frequent spot inspections -- sometimes as frequently as every 5 days, depending on methane levels -- to check on potential ventilation problems at mines that liberate large amounts of the explosive gas.

Agency records indicate MSHA completed these required periodic spot inspections in January, February and March 2010.

The last spot inspection prior to the explosion was on March 25, and another spot inspection was not performed until April 12.

MSHA spokeswoman Amy Louviere said that the agency had Upper Big Branch on a schedule for spot inspections every 10 days from January through the end of March 2010. Sometime during that period, agency officials found higher levels of methane, and the mine's spot inspection frequency was to be increased to every five days starting April 1, Louviere said.

Louviere said that MSHA believes a new spot inspection was due to be conducted sometime between April 2 and April 6. The explosion occurred on April 5.

"We don't live in a perfect world," Main told lawmakers. "We wish that we did. With all of the pieces that we inspect, there are some quality improvements that we could make."

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