The man who oversaw construction of the underground Omega block seal that failed at the Sago mine in West Virginia, causing the deaths of 12 men, says the company used "the easiest and fastest" way to build the wall, and that some miners were sent underground after falsifying safety training documents.

"That's a cheap block.... And that's the cheapest way for them to build them," James F. Scott told the Pittsburgh Post-Gazette. Mr. Scott was working as an outside contractor at the time he oversaw a crew that constructed the series of 10 walls used to seal off an abandoned portion of the mine.

The seal -- built of the dense, foam-like block -- was pulverized when a buildup of methane ignited behind it Jan. 2. One miner died immediately and 12 others were stranded underground. Eleven of those stranded miners died of carbon monoxide poisoning.

Omega block, a lightweight foam and fiber material manufactured by a Westmoreland County firm, has figured in at least one other fatal mine accident this year. Five workers at a Kentucky mine died when an Omega seal was blown apart by an apparent methane explosion May 20.

Researchers at the Pittsburgh office of the National Institute of Occupational Safety and Health plan another series of blast tests Aug. 4 on an Omega seal they believe will replicate the ones built at Sago.

In addition to suggestions the blast might have exceeded the 20 pounds per square inch the wall was built to withstand, protocols for the test say the seals "may not have been constructed properly" and that "construction materials may have been substandard."

The description for building the NIOSH test seal diverges substantially from the standard for an approved Omega block seal, but matches descriptions of the construction given by witnesses, including Mr. Scott, before the investigating panel.

The NIOSH test wall will be built atop a 1¹/_2-inch-thick layer of dry mortar, called BlocBond, with no mortar between the vertical joints in the first row.

On those remaining, mortar is to be "forced into the vertical joints of each course by gloved hand" and is "to be thrown along the top off seal to fill any remaining gap."

Standards for the Omega block seal call for it to be cemented to the mine floor, not placed atop dry powder, and for all joints to be fully mortared.

Mr. Scott, who says he believes he did the best job he could with the material, said it was difficult to mortar all the joints before laying the block, which is why crew members forced it into the cracks by hand.

"You do it the easiest and fastest way," he said. He said crews threw wet mortar into the gap atop the block, rather than laying it with a trowel, because "it was narrow. You couldn't get nothing back in it. It was 40 inches deep across the top."

Mr. Scott, who signed on with the Sago mine as a full-time employee after his crew built the seal, also said a Sago supervisor had him sign a document saying he had received safety training that he was not given.

Mr. Scott said mine officials at Sago have since made certain that all miners are trained in safety, but in his case, prior to the explosion, "I wasn't." Instead, he said, he had to learn on his own the escape routes from the mine and other safety details.

"Everything -- on escape ways out of that mine -- everything, I done it on my own. I didn't know how to get out of there," he said.

In the course of a joint state-federal investigation into the Sago disaster, another miner, John Nelson Boni, also said he had falsified a training form.

Questioned Jan. 19 by investigators, Mr. Boni at first described a safety training class he said he took in October, with instructions on changes to roof conditions, mine ventilation and use of self-rescue devices. When a panelist asked for more details, Mr. Boni admitted he had not received the training.

"Well, you got me," he said. "I didn't take that class. And you're going to catch me anyway, so I'm going to tell you." He said a mine official had him sign the form.

"They just brought it in for me and I signed it," he said.

During public hearings in May, a solicitor with the federal Mine Safety and Health Administration revealed that the agency had opened an investigation into several Sago officials.

An officer with International Coal Group, the mine's owner, acknowledged at the time that the inquiry revolved around Mr. Boni's assertion that he was asked to sign a form for training he had not received.

ICG Vice President Charles Snavely issued a written statement last night saying ICG "believes that the company provided the miners with all the required MSHA training" and provided other training opportunities since taking over the mine. Mr. Snavely's statement also said the company believed the seals "were constructed consistent with the approved plan and common accepted practice to withstand the 20 psi static force required by MSHA's mandatory standards."

Mr. Boni, who retired from Sago after the Jan. 2 explosion, declined to comment yesterday.