U.S. coal miners remain vulnerable to explosions similar to those that have killed 17 of their colleagues this year, said West Virginia's lead investigator into the Sago mine disaster.

	MINE DANGERS Mine Safety Digital model will help gauge force of Sago blast

Recent moves by federal mine safety officials to limit the danger are a step in the right direction but still represent "a kind of Band-Aid approach," said J. Davitt McAteer, who himself was head of the U.S. Mine Safety and Health Administration under President Clinton.

"It's a partial, initial step," said Mr. McAteer this week. "It does not take care of the problems."

The problems, he said, include the hundreds of underground seals made of Omega Block, the lightweight, reinforced fiber material that failed at Sago on Jan. 2, resulting in 12 deaths, and at the Darby mine in Kentucky on May 20, where five miners died.

In his July 19 preliminary report on Sago, Mr. McAteer called on West Virginia to continue its moratorium on the use of Omega Blocks for seals, which MSHA approved for use in 1992. He also said officials should determine the number and location of existing seals and, ultimately, retrofit those seals to make them explosion-proof.

Until then, he concluded, "every sealed area in every underground coal mine in West Virginia and throughout the United States should be considered a potential time bomb -- and treated accordingly."

MSHA spokesman Dirk Fillpot yesterday said inspections of all alternative seals, and any needed remedial action, will be completed by the end of September.

Mining deaths have been on the decline in recent years. There were a record low 22 in 2005.

But since 2001, there have been three mining accidents, all of them underground explosions, that resulted in mass casualties. Thirteen miners were killed in an explosion in Brookville, Ala., in September 2001, then the 12 deaths at Sago and five at Darby.

In the five years prior to 2001, no mining incidents involved three or more deaths, according to MSHA records.

The similarities of the Sago and Darby disasters -- both involved methane explosions that destroyed a nearby Omega Block seal -- has mine safety officials scrambling to prevent another catastrophe.

But disagreements have emerged about what steps must be taken.

The same day Mr. McAteer released his preliminary report on Sago, MSHA sent a bulletin directing mine operators that all new alternative seals must withstand a force of 50 pounds per square inch, up from the previous 20 psi standard.

That begged the question: How safe are the existing seals built to meet the 20 psi standard?

Ray McKinney, MSHA administrator for coal mine safety and health, told operators that existing alternative seals must be inspected "to verify that correct construction practices were followed" and they must take steps if the air quality is potentially explosive.

That overlooks what happened at Sago, said Mr. McAteer.

"Construction is a minor part of the problem. It is the materials themselves."

Mr. McAteer was even more direct in his report, saying the Omega Blocks "should never have been approved for the purpose of containing an explosion originating in a sealed area."

Mr. Fillpot said the number and location of Omega Block seals is collected at the district offices and has not yet been aggregated at MSHA's Arlington, Va. headquarters.

But in interviews with state mining officials this week, the Pittsburgh Post-Gazette found a wide disparity in the use of Omega Block seals in the region's coal-producing areas.

Pennsylvania has no permanent Omega Block seals in its 77 underground mines, said Joseph Sbaffoni, director of Pennsylvania's Bureau of Mine Safety, although some mines may use Omega Blocks as stoppings to direct air flow in the mines.

"Personally, I never cared for these Omega Blocks because they fall apart," Mr. Sbaffoni said.

West Virginia, by contrast, has 924 Omega Block seals in 56 different mines. State officials have placed a moratorium on any new Omega Block seals and "we're trying to determine what is the best thing for us to tell the operators" about existing seals, said Caryn Gresham, spokeswoman for the West Virginia's Office of Miners' Health Safety and Training.

Sixteen of Virginia's 118 coal mines have used Omega Blocks to construct seals, according to Michael Abbott, of the Virginia Department of Mines, Mineral and Energy. Last month, MSHA inspectors cited two Dominion Coal Corp. mines in Virginia for potentially dangerous methane levels behind Omega Block seals, and both are being rebuilt.

Following the Darby mine explosion, Kentucky officials ordered an immediate inspection of all alternative mine seals in the state's 196 underground operations. They found 463 seals, 236 of them made of Omega Block.

During that inspection, one Kentucky mine operator discovered an Omega Block seal had inexplicably blown out. The mine was shut down until its other 30 Omega Block seals were rebuilt.

That may be just the beginning.

Following this year's mining disasters, Kentucky's legislature gave state officials authority to enforce MSHA-approved seal plans. Now there are indications they may no longer approve plans that include Omega Blocks, said Mark York, spokesman for the Kentucky Environmental and Public Protection Cabinet.

"With the new psi standard," said Mr. York, "there's a belief that it may eliminate the use of Omega seals."