THE HOIST MECHANICS WERE IN THE PROCESS OF CHANGING OUT THE MAIN HOIST CABLE. THE CAGE WAS SECURED AND A DYNOLIFT WAS BEING USED TO PULL THE CABLE AS THE HOIST WHEELED. WHEN THE DRUM RELEASED, THE COUNTERWEIGHT FELL. THE COMPUTER RECOGNIZED THIS AND SET THE BRAKES. THE DYNOLIFT WAS PULLED 30 FEET INTO THE SHAFT AREA BEFORE THE BRAKES SET.