EMPLOYEE WAS STANDING IN FRONT OF GYRO PIT, DIRECTING DUMP BERM REMOVAL. TOP LIP HAD BEEN BROKEN FREE AND AS FRONT END LOADER TILTED BUCKET UP TO MOVE IT OUT, IT SLID UP AND CLOCKWISE TOWARD THE EMPLOYEE. HE LEAPED BACK TO AVOID BEING HIT AND DROPPED 13 1/2 FEET DOWN INTO THE CLEARED PIT.