Lightning and seals no new problem
ADGER, ALA. -- At about 8:15 p.m. on July 9, 1997, miner Robert Acklin felt a blast of air as he stood at the bottom of the elevator shaft inside U.S. Steel Mining’s Oak Grove Mine.
Deep beneath the rolling hills just south of Birmingham, Ala., Acklin smelled something burning. Smoke blew toward the mine’s main track.
Gas readings showed rising levels of deadly carbon monoxide. U.S. Steel evacuated the mine. No one was injured.
Later, federal investigators found that a methane explosion in an area that had been mined-out and sealed had destroyed one foam-block seal and damaged two others. They blamed lightning, but said they couldn’t figure out for sure how the charge got into the mine.
“All parties agree that if lightning is the ignition source, that the path into the sealed area is undefined,” concluded a report by the U.S. Mine Safety and Health Administration.
Agency investigators also found that the Oak Grove explosion exerted forces greater than 20 pounds per square inch. Five years earlier, MSHA had written a rule that required mine seals to be able to withstand a blast of up to 20 pounds per square inch.
The Oak Grove explosion was a clear indication that MSHA’s regulations on seal strength were not adequate. But the agency did nothing about it — for nearly a decade.
One year ago today, an explosion tore through International Coal Group’s Sago Mine in Upshur County. Twelve miners died.
So far, two state investigations have blamed lightning. Neither probe has figured out how lightning got into the mine. But both have found that the explosion was far stronger than the 20-psi standard mine seals were required to meet.
Five months after Sago, then-acting MSHA chief David Dye issued a temporary moratorium on new seals built under the agency’s 20-psi standard. State officials in West Virginia took similar action.
But the Sago disaster might not have happened if regulators and the coal industry had heeded the warnings from Oak Grove, and from a series of other lightning-induced explosions in the U.S. and abroad dating back more than 30 years, federal and state investigators have learned.
Today, thousands of underground miners across the coalfields work alongside foam-block seals that experts now acknowledge don’t meet the “explosion proof” test required by the 1969 federal mine safety law.
So far, no one has a plan to protect these miners.
During a Dec. 11 meeting, Sago families pressed West Virginia mine safety director Ron Wooten for answers. What would happen, they asked, if another storm occurred near an underground mine with foam-block seals?
“I wouldn’t want to be in there,” Wooten responded, according to several family members who attended the meeting in Buckhannon.
Phil Smith, a spokesman for the United Mine Workers union, said that Wooten’s answer was simply unacceptable.
“I think there are 14,000 coal miners in West Virginia that wouldn’t want to be in there, either,” Smith said.
UMW officials are demanding a rule to require coal operators to evacuate underground mines during lightning storms.
Wooten said that isn’t practical.
“Let’s assume that the explosion was caused by a roof fall behind the seals,” Wooten said. “Do you evacuate the mine to wait for a roof fall? You would never know.”
Wooten’s boss, Gov. Joe Manchin, said last week that he isn’t sure there is anything state regulators can do about the problem.
“Mother Nature is what she is,” Manchin said. “That’s the bottom line. I don’t know if we can predict the [lightning] strikes. If we can do that, we will take precautions.”
An early debate
In 1969, when Congress passed a national mine safety law, the issue of sealing mined-out areas was among the many controversial issues.
Generally, coal operators wanted to avoid having to do periodic safety checks in the vast underground areas they had mined and moved out of. Companies want to seal those areas and then forget about them.
Lawmakers agreed, at least in part. Coal companies could seal mined-out areas. But when they did, those areas must “be isolated from the active workings of the mine with explosion-proof seals or bulkheads.”
In 1970, government rules to implement that part of the law stated that “pending the development of specifications for explosion-proof seals or bulkheads, seals or bulkheads may be constructed of solid, substantial and incombustible materials sufficient to prevent an explosion that may occur on one side of the seal from propagating to the other side.”
For years, these seals were built with concrete blocks. But those were not very popular with mine operators or with miners. They were expensive, and building seals with them was time-consuming and backbreaking work. So companies did not always seal mined-out areas. Sometimes they kept them open and were required to ventilate and periodically check them.
Then, in 1981 and 1984, 16 miners died in two major explosions in Pennsylvania and Tennessee that were blamed on poor ventilation practices in mined-out — also called gob — areas.
Through the 1980s and into the early 1990s, various government agencies were exploring the potential use of foam blocks — in particular a brand known as Omega Blocks — for mine seals.
In 1988, MSHA proposed to rewrite its seal construction rules. Under the proposal, operators could use “alternative construction methods or materials” as long as they provided “at least equivalent protection” to miners from explosions.
When they finalized the rule four years later, MSHA officials inserted the 20-psi standard, defining blocks that meet that test as “explosion proof.”
Agency officials cited a 1971 federal Bureau of Mines study they said made the case for this 20-psi standard. But the study, by the late researcher Donald W. Mitchell, “makes for deeply disturbing reading in the wake of Sago,” as state investigator Davitt McAteer wrote in his Sago report.
For example, the Mitchell study notes that federal standards for sealing mines on government property — dating back to 1921 — required seals to be more than twice as strong as the 20-psi MSHA rule.
Explosions can be much stronger than that, the study said.
More than 200 feet from the ignition point, blasts aren’t expected to be much stronger. But close to the blast point, “No one can foretell what forces would be exerted on a bulkhead in the event of an explosion,” the study said.
Also, the Mitchell study found, the United Kingdom determined that a 50-psi standard “gives a good margin of safety in practice” after studies of disasters there in 1933 and 1960. In Poland and Germany, the study said, the standard for seal construction is 72 psi.
West Virginia University law professor Patrick C. McGinley studied the MSHA seal rules as part of McAteer’s independent investigation of the Sago disaster.
McGinley concluded that the 20-psi standard “is inconsistent with the unambiguous statutory mandate of the Mine Act that coal mine seals be ‘explosion proof.’”
But at the time it was written, the mining community did not have a chance to criticize the standard. MSHA officials inserted it into the final rule, a move that eliminated the chance for public comment.
The Sago disaster was far from the first time lightning hit a coal mine.
One published paper notes a lightning strike at a mine in the United Kingdom as early as 1883. A 1908 newspaper article described a lightning strike that killed three workers in September that year at a mine in Pennsylvania.
In April 1948, the U.S. Bureau of Mines published a paper called “Protection Against Lightning at Surface and Underground Mining Plants.” The report listed dozens of lightning-caused explosions at various types of mining operations.
“This paper presents some information on the effect of lightning on the mining industry, and it will be noted that both surface and underground work is affected and that, while premature detonation of explosives is one of the main hazards in the mining industry due to lightning, it is by no means the only harm to the industry in this cause,” the bureau report concludes.
More recently in South Africa, mining experts have noted “a considerable number” of underground mine explosions linked to lightning. One such incident, in 1974, killed 13 miners, according to a paper presented in 1987 by mining engineer H.J. Geldenhuys. Geldenhuys describes a series of incidents in which lightning caused premature detonation of mine explosives or ignited underground methane blasts.
In response, South Africa drew up its Code of Practices for the Avoidance of Hazards Underground due to Lightning. South Africa’s mining industry came up with a way to examine individual mines and predict the likelihood that lightning could cause an explosion in them. It included additional steps to prevent such accidents.
At one mine, underground blasting was suspended and miners withdrawn from the area during a severe storm.
At another mine, lightning actually detonated explosives, but no one was hurt because miners had already been evacuated because of the storm. During the same storm, an adjacent mine did not evacuate, and a miner was hurt when lightning ignited explosives there, Geldenhuys reported.
In the United States, regulators and the mining industry did not respond so quickly to a string of eight lightning-induced explosions at mines in Alabama and West Virginia. No new regulations were written, and no large-scale investigation appears to have been done.
Officials from the National Institute for Occupational Safety and Health did issue one report in 2001 that tied some of the incidents together.
NIOSH concluded that mine operators should try to eliminate flammable mixtures of methane in sealed areas, and remove wires, pipes, old batteries and other ignition sources from those areas.
But, as McAteer noted in his Sago report, neither NIOSH nor MSHA “acknowledged awareness” that sealed-area explosions like the one at the Oak Grove Mine could generate more than 20 psi of force.
During public hearings in May, ICG President Ben Hatfield testified that his company planned to evacuate mines with explosive mixtures of methane behind seals during lightning storms until a better alternative can be devised.
But today, despite the 12 deaths at Sago, government officials and the rest of the industry have done little to protect miners from future lightning-caused explosions.
A group of industry officials told The Associated Press as much for a news story two weeks ago.
“I’m not aware of any confident assertions about what should be done,” said National Mining Association President Luke Popovich, “either within our industry, labor or among regulators.”
Bill Caylor, president of the Kentucky Coal Association, said it’s not clear how big a problem lightning is.
“It can be an enormous problem, but it hasn’t been a problem in the past,” Caylor said. “This may just be a one-in-a-million occurrence.”
Massey Energy President Don Blankenship told the AP that the chances of a future lightning-caused explosion may not justify the expense of trying to prevent such an incident.
“If you spend millions of dollars or spend all your time trying to prevent a lightning strike, you probably are endangering people,” Blankenship said. “People don’t like to accept the realities of it. The next accident is highly unlikely to be caused by lightning.”
UMW officials and some Sago families do not necessarily believe that lightning ignited the Jan. 2, 2006, explosion. But if it did, they say, something has to be done.
UMW President Cecil Roberts raised the issue in May, in a closing statement at a public hearing into the Sago disaster.
“I don’t know if you’ve picked up on the seriousness of this question about lightning being able to hit a power line somewhere or be absorbed from a magnetic field somehow as a result of a lightning strike on the ground, the power line picking it up, carrying it a long distance, going into a piece of equipment of some type, a transformer outside, traveling two miles underground, jumping across a space of eight feet, making its way past the seals,” Roberts said.
“I’ll submit this to you. It’s one of two things here. Either we’re going to have to close every coal mine in the United States of America every time there’s a thunderstorm, or this is an erroneous, ridiculous, preposterous position for anybody to be taking.”
Pam Campbell, whose brother-in-law Marty Bennett died at Sago, said two weeks ago, “If it’s lightning, so be it. But I asked [Governor Manchin] what plan he has for keeping this from happening again, and he has no plan.”
To contact staff writer Ken Ward Jr., use e-mail or call 348-1702.