Mechanical failure in a gearbox is thought to have caused the ski lift accident in Maine that injured seven guests over the weekend.

The accident at Sugarloaf occurred Saturday and prompted the evacuation of the King Pine lift. Now, the ski resort is saying preliminary findings point to a “major mechanical failure in one of the two gearboxes connecting the lift’s electric motor to its drive bullwheel.”

The bullwheel, according to the resort, is a large metal wheel around which the lift cable is tensioned. The lift cable supports the lift chairs.

A failure of the gearbox, which was inspected the day before the accident, de-coupled the bullwheel from the lift’s primary brake as well as an anti-reverse brake, prompting a lift attendant to pull an emergency brake to stop the lift from rolling back even farther than it already had.

"Our first concern remains with those who were injured, and those who went through a truly frightening experience," said Ethan Austin, who is the resort’s director of marketing. "Based on what we know now, we're grateful that this situation wasn't any worse. It's too soon to say what, if any, changes to operational protocols will be made, and part of that determination will hinge upon what's revealed by the next stages of the investigation."

Austin said the lift will remain closed pending further investigation.