The Department Of Labor will begin a new search for the cause of the explosion inside the Sago mine.

For the first time, federal investigators will use computer modeling to recreate the conditions inside Sago, including the pressure on the mine's safety seals just moments before the blast.

The Sago explosion trapped 13 miners and killed all but one, making it the deadliest mining accident in West Virginia history in 38 years.

A state investigation previously reported that lightning was the possible cause of the blast, but federal officials want a more definitive answer.

Mark Skiles, of the Department of Labor Mine Safety division, said, "There were a lot of bright people looking at this for a long time and a lot of things point to lightning, but we still do not have definitive proof that is was lightning."

However, some miners said the department needs to do more than a study to prevent a similar tragedy. They contend the government must act quickly and significantly to increase the number of mine safety inspectors.

Cecil Roberts of the United Mine Workers of America said, "There's a dire need to hire additional inspectors."

President Bush signed legislation to add new inspectors over the coming months, but in the meantime, the administration said the study will help come up with better safety regulations.

"If nothing else, let's learn enough that we can keep it from happening again. We have that chance and we're going to take advantage of it," Skiles said.

The investigation is expected to cost about $250,000 and will take several months to complete.

Federal mine safety inspectors will work with the Army Corps of Engineers to put the 3-D computer model together.

If successful, investigators said they will also learn precisely how much pressure the blast put on the mine's safety seals.

-Renee Cardelli and Scott MacFarlane, NEWS9