Lightning involved’ at Sago, expert says
State investigators have concluded that lightning caused the Sago Mine disaster, but a report to be released Monday will still not explain exactly how the electrical strike ignited methane deep inside a sealed area of the Upshur County mine.
An expert hired by the state Office of Miners’ Health, Safety and Training agrees with the lightning theory originally promoted by mine owner International Coal Group.
“I’m certainly convinced that lightning was involved,” said E. Philip Krider, a University of Arizona physicist who has studied lightning extensively.
But Krider said the state is still waiting on test data on the electromagnetic fields in and around the mine, and is working to schedule more tests to try to pinpoint the lightning’s path into the mine.
“We’ve identified a number of possible mechanisms and we’re planning further tests and perhaps even measurements during a lightning storm in that area to try to pin down the exact mechanism,” Krider said.
In an interview Wednesday afternoon, Krider said he was busy helping to edit the state agency’s report on the Sago disaster. State officials plan to provide the report to Sago families Monday morning, and then make it public during a state Board of Coal Mine Health and Safety meeting that afternoon in Buckhannon.
The 6:30 a.m. explosion on Jan. 2 at the Sago Mine killed one miner outright. Twelve other workers became trapped underground, and 11 of them died from carbon monoxide poisoning before rescuers reached them 40 hours later.
Krider pointed to two lightning strikes that straddled the mine to the northwest and southeast at about the time of the explosion.
Both were powerful strikes, but the one about a mile northwest of the mine portal was especially strong, about three times as powerful as a typical strike, Krider said. Near that spot, investigators found a tree that appeared to have been seriously damaged by lightning, he noted.
In his report on the Sago disaster, special investigator Davitt McAteer said that lightning could have followed a path from the surface, through the ground and into the mine, possibly using a submerged pump or pump cable, or wire roof mesh to jump into the sealed area.
Or, McAteer said in his report, the lightning could have somehow made it to the mine portal, and then traveled back to the sealed area along phone wires, a conveyor belt structure or wire roof mesh.
Krider said state investigators have not been able to rule out any of these scenarios.
Krider said it is also possible that there was another lightning strike closer to the sealed area that was not picked up by the nation’s lightning detection systems.
“We need to understand better both the possibility of a direct current into the mine and an indirect current,” Krider said. “There are a lot of hypotheses, but we don’t have all of the answers yet.”
In his report, McAteer also questioned whether ICG took all required steps to try to protect the mine against lightning strikes.
“It is clear that ICG failed to properly ground the mine’s electrical power infrastructure in its entirety, and failed to install lightning arrestors at some key locations as required by federal regulations,” McAteer said. “Pending further investigation, the question of whether these failures directly contributed to the explosion and subsequent loss of life remains to be resolved, but there is no question that they represent serious failures of mine management.”
To contact staff writer Ken Ward Jr., use e-mail or call 348-1702.