FAIRMONT — The explosion at the Sago Mine occurred in a mined-out area that had been sealed perhaps only weeks before the Jan. 2 disaster, state government records show. A state mine safety inspector examined the seals Dec. 12 and determined that they were properly constructed, according to the records. “The seals may be closed,” wrote John Collins, an inspector with the state Office of Miners Health, Safety and Training. “The seals are built as approved.” Less than three months before the blast, on Oct. 14, state regulators had approved a plan to seal an area of the mine called “2nd Left Mains.” In media coverage, the bodies of 11 of the miners who died in the Sago disaster were reported found in “2nd Left.” But actually, they were found in a new production section, called “2nd Left Parallel.” That section was located between the sealed “2nd Left” and another section called “1st left.” In that sealing plan, state officials approved the use of “Omega blocks,” a product resembling dense plastic foam. During a public meeting Thursday, C.A. Phillips said the explosion blew out the seal that protected the active mine workings from the mined-out 2nd Left area. Officials from International Coal Group, which owned the mine, have said the explosion blew the seals into the active mine, a finding that led them to believe the blast occurred in the sealed-off section. On Thursday, Phillips told the state Board of Coal Mine Health and Safety that, “The seals, made with foam, could withhold pressures of five pounds per square inch.” Rick Glover, a board member and retired United Mine Workers safety official, said those seals were much too weak. Glover said federal mining regulations require that underground mine seals, installed to isolate mined-out areas from active sections, must be able to withstand pressures of 20 pounds per square inch. U.S. Mine Safety and Health Administration rules actually require all seals to be built using “solid concrete blocks.” Alternate materials can be used only if they will withstand 20 pounds per square inch of pressure, the MSHA rules state. In a summary of its research on coal mine seals, the National Institute for Occupational Safety and Health reported that “ventilation seals are used extensively in mining to safely isolate old workings and fire areas from the active sections of a mine to protect underground workers from explosions. “Without reliable seal designs, miners’ lives could be in jeopardy from the consequences of an underground explosion,” said the NIOSH report. NIOSH said one company alone reported that its seal products were used an average of 70 times per month in underground mines. In its summary, NIOSH also noted that an explosion occurred in a sealed area of the Gary 50 Mine, owned by U.S. Steel, in Pineville in June 1995. That mine used 4-foot-thick pumped cement seals tested by NIOSH and approved by MSHA. The seals “effectively contained the explosion, thereby sparing the miners working nearby,” NIOSH reported. To contact staff writers Ken Ward Jr. or Paul J. Nyden, use e-mail or call 348-1702 or 348-5164.