CARRABASSETT VALLEY — Maine’s Sugarloaf ski area has completed the $800,000 upgrade of a chairlift that rolled backward last season, injuring seven skiers.

The updated King Pine lift reopened on Monday at Sugarloaf.

Resort officials say the quad lift features a redesigned gear box and the latest electronic, braking, and anti-rollback technology. The towers and chairs were from the previous lift.

Investigators determined the mechanical failure on the 27-year-old lift in March was caused by a broken drive shaft in a gearbox. A faulty switch prevented an anti-rollback system from locking the lift and an emergency braking system failed to activate automatically.