Sago lacked lightning protectors
The Sago Mine violated basic electrical safety rules by not installing equipment to prevent lightning from sending a charge into underground mine workings, U.S. and West Virginia investigators have learned.
At least two electrical systems at Sago were not equipped with lightning arresters similar to surge protectors, the mine’s chief electrician told investigators in a sworn statement.
Inspectors who swarmed over the Sago Mine after the Jan. 2 explosion found similar violations on three other electrical systems, according to new records from the U.S. Mine Safety and Health Administration.
Sago Mine owner International Coal Group has pushed the theory that lightning caused the explosion. But company press releases have not mentioned the serious electrical violations related to the lack of lightning-protection devices.
State and federal investigators are examining the possibility that lightning hit one of the mine’s surface electrical systems and — with nothing to stop it — sent a charge underground, eventually igniting a buildup of methane in a sealed area deep in the mine.
The lightning theory — along with ICG’s electrical violations — is expected to be a central topic when state and federal officials convene a public hearing on the Sago disaster, starting Tuesday in Buckhannon.
Twelve miners died and a thirteenth was critically injured after an explosion ripped through the Upshur County mine at about 6:30 a.m. Jan. 2.
It was the worst coal-mining disaster in West Virginia in nearly 40 years.
So far, investigators believe the explosion occurred inside an area of the mine that ICG recently had sealed. The company stopped mining in the area because of repeated roof falls, records show.
In mid-March, ICG issued a news release that declared the company’s “independent accident investigation” had concluded lightning caused the explosion. ICG said that, “The precise route by which the lightning electrical charge traveled from a surface strike location to the sealed area remains under investigation.”
In a three-page briefing paper, ICG said, “Although it appears that lightning was the source of the energy for ignition, it has not been determined how it passed into the sealed area.
“There is no obvious conduit directly from the surface, such as a borehole with a metal casing, although searches have been conducted on the surface,” ICG said. “The track, belt, conveyor, electrical cables and steel roof mesh did not pass through the seals and it does not appear they were a direct conduit for electricity into the sealed area.”
ICG added that one of the lightning strikes the morning of the explosion was 300 feet away from a power pole that supplied power to the mine.
“It is possible that the electrical energy entered the mine through this mechanism, traveling perhaps along the conveyor belt structure,” the company said.
ICG repeatedly has refused to make any company officials available to answer questions about its investigation. During interviews with government investigators, ICG has declined to provide details of the company inquiry.
It is not clear what — if any — details of its investigation ICG will be asked to make public during the government hearings this week.
Under federal mine safety rules, all power lines and phone cables that lead into underground mines must be equipped with lightning arresters.
Lightning arresters are protective devices that limit surges of electricity from lightning strikes or equipment failures. They prevent damage to electrical equipment and, in the case of underground coal mines, help to prevent lightning from sparking fires or explosions.
Aboveground power poles, power transformers and various types of steel superstructures are commonly equipped with lightning arresters.
State and federal investigators quizzed Denver Wilfong, Sago’s maintenance foreman and chief electrician, about its lightning arresters during a two-day interview in mid-February.
Wilfong testified that the mine did not have arresters on parts of its carbon monoxide monitoring system, according to a transcript of his sworn statement.
Also, Wilfong testified that Sago had not installed arresters on its trolley cable, a line that typically is used to run power for underground equipment, but at Sago was used for a phone line.
“We failed to have them on the trolley,” Wilfong said during an interview Feb. 16 at the federal courthouse in Clarksburg. “They should have been on there.”
During a visit to the Sago Mine six weeks later, MSHA inspectors handed Wilfong three citations that alleged violations of the lightning arrester requirements.
One of the citations was not considered by MSHA to be serious. It concerned the lack of lightning arresters on a power cable to the mine’s fan house.
The other two citations were listed by MSHA as “significant and substantial” and “reasonably likely” to cause injuries. Each concerned the lack of lightning arresters on power conductors connected to the underground mine.
The three citations, issued by MSHA on March 31, were released by the agency last week.
They were among 117 citations issued that day as part of the agency’s ongoing examination of safety problems at the Upshur County mine. MSHA did not publicly announce the citations, but ICG issued a news release about them on April 7.
In its release, ICG said, “None of the citations are related to the accident.
“The vast majority were found to be unlikely to cause injury, and none of the conditions actually caused any injury,” the company said.
ICG said that all but one of the problems cited by MSHA had been corrected by the time the company’s release was issued. But as of Friday, MSHA still listed five of the violations as not having been abated.
“Safety remains our top priority, as evidenced by our prompt attention to MSHA’s concerns,” IGC President Ben Hatfield said in the company release. “As we have said before, we welcome the increased scrutiny we face from state and federal regulators and will continue to work with them to keep our mines safe.”
Staff writer Ken Ward Jr.’s continued reporting on the Sago Mine disaster and mine safety is being supported by a fellowship from the Alicia Patterson Foundation.
To contact Ward, use e-mail or call 348-1702.