Within hours of the Jan. 2 explosion at the Sago Mine that trapped and killed 12 men, some already believed lightning was the likely cause.

Powerful bolts had peppered nearby Buckhannon that morning, some striking close to the underground coal mine where two 13-man crews were just starting the day shift.

Two-and-a-half months later, the mine's owner said Tuesday it has evidence to prove the theory. Although it cannot fully explain how, International Coal Group Inc. officials said they believe electricity from above found some conduit into the earth, sparking methane gas that had accumulated in a worked-out, sealed-off chamber.

It was "unpredictable and highly unusual" and ordinarily hard to prove, said CEO Ben Hatfield.

ICG's investigation of the blast found what Hatfield believes is compelling evidence from three different clocks in three different locations.

At 6:26 a.m., professional weather watchers confirmed an unusually large lightning strike near the mine, he said. Some 70 miles away in Morgantown, a U.S. Geological Survey station confirmed a seismic event at Sago. And deep inside the mine, atmospheric alarms sounded, signaling the carbon monoxide that comes with fires and explosions.

One crew escaped the blast, but another was trapped some 260 feet underground for more than 41 hours. By the time rescue teams reached them, all but one had perished in the poisoned air. Survivor Randal L. McCloy Jr. is still recovering from brain damage, but was well enough Tuesday to leave his Morgantown rehabilitation hospital for a trip to his home in Simpson, where he spent three hours visiting with family.

Hatfield said ICG's investigation is not the final word on the explosion, but that he is confident a joint federal-state investigation also being undertaken will reach a similar conclusion.

Gov. Joe Manchin, a constant presence during the disaster, did not immediately weigh in on the company's findings and a spokeswoman said it would be premature to discuss them until the state-federal probe is finished.

Tony Oppegard, a former MSHA official, said he also wants to see the final ruling from federal investigators.

"If, in fact, that is the cause, that doesn't end the inquiry in terms of the company's liability," said Oppegard, now a Kentucky lawyer who represents coal miners in injury cases. "It's a frequent refrain when there's an accident to call it an act of God."

Hatfield said ICG does not claim to have all the answers yet.

He said his investigators found no power source in the sealed area and no track or conveyor belt from the active parts of the mine extended into it. Steel mesh that had once lined the roof of the worked-out section had been removed, and there was no energized electrical equipment in the area.

One of the confirmed lightning strikes that morning was 300 feet from a utility pole that supplied power to the mine. ICG said it is possible an electrical charge entered the mine that way, perhaps traveling along a conveyor belt frame.

LuluBelle Jones, whose son Jesse died at Sago, said she is not surprised to hear lightning was the likely cause. "It's what we thought," she said.

Although the Mine Safety and Health Administration had cited the mine for 208 violations in the months leading up to the accident, Hatfield said the company's findings show that none of those violations was related to the blast.

The explosion took place behind 40-inch-thick seals designed to withstand 20 pounds per square inch of pressure. The seals were pulverized by forces the company believes were at least three times that.

Hatfield told The Associated Press late Tuesday that ICG will no longer install seals at Sago and will ventilate existing sealed areas with boreholes to the surface. In time, the company hopes to adopt a technology used in some other mining countries - pumping nitrogen into the abandoned areas to make the gases inert.

"We will not be constructing seals until we can be absolutely certain that an explosive environment is not being created," he said.

ICG bought the Sago Mine near Buckhannon from bankrupt Anker West Virginia Mining Co. last March. The operation has been producing coal since September 1999 and had 145 employees at the time of the accident.