NEWBURY – Mount Sunapee said they were aware of a problem with the North Peak Triple chair minutes before its catastrophic failure Christmas Day.

They were in the process of off-loading and evacuating the lift when it stopped abruptly, bounced wildly and ejected one teen. A 13-year-old boy from New Jersey suffered a fractured elbow. Twenty-two were evacuated from the lift. The bull wheel that drives the lift rope at the top was broken from its housing, while the cables remained on the lift towers.

David Barrett, director of safety services for the New Hampshire Department of Safety, said yesterday the cause of the lift accident has been determined to be a bearings failure. The 1987 lift had its original bearings and it had begun to make noises, but state and resort officials thought they had time to fix it, were watching it and were planning to have the lift down for replacement of the bearings Dec. 26 and 27.

Barrett said officials at Mount Sunapee notified them of their concern. Don Martin, a tramway safety inspector for the state, came Dec. 23 to inspect the lift.

The parts for the lift were en route.

Martin allowed the lift to continue to operate. Three hours of operation later, the lift broke.

Sunapee had a mechanic listening for any change in the noise. When the bearing noise became constant, Barrett said, the decision was made to stop loading the lift and to shut it down once the last person on the chair was unloaded. But four and a half minutes into a seven-minute off-load, the chairlift stopped abruptly.

The boy, who was with his father on the lift, suffered a fractured elbow and dislocation and was treated at both Dartmouth-Hitchcock Medical Center and New London Hospital. Barrett said he fell a distance of less than 20 feet on to snow.

The lift remains closed while repairs are now under way.

Gamble said the bearings were making a small noise and "we were monitoring it," he said. "At the time there did not seem to be a reason to believe there would be a failure of the lift," he said.

Barrett said there are no records in the country of such a catastrophic failure involving bearings, and the resort did not have reason to believe that an accident of this magnitude was imminent.

The lift had no history of problems, and there are 11 others in the state with similarly clean records.

Other ski areas that have this lift have checked for problems and found none, Barrett said.

Gunstock General Manager Greg Goddard said the Tiger and the Pistol chairs at his mountain are similar in vintage and are from the same manufacturer, Doppelmayr. Those chairs had the bearings replaced in 2003 from their original.

The last lift in the nation to face a bull wheel break was in a 1984 Yan lift which broke at Keystone, ejecting 50 skiers and killing two. In that case, the cause was a faulty weld.

Gamble said this catastrophic failure has lift mechanics around the country stunned, because a failed bearing has never caused such a loss.