Abstract: A conveyor apparatus for elevating loose bulk material from one level to another, as in self-unloading ships, and more particularly a dual belt conveyor-elevator having a relatively long horizontal feed section, and further including a belt take-up apparatus and system including a normal pressure mode for tensioning the outer belt of the dual belt conveyor-elevator under normal operating conditions, the belt take-up apparatus and system also including a high pressure mode which is connected in tensioning relation to the outer belt of the dual belt conveyor-elevator upon loss of motive driving power to the dual belt conveyor-elevator. The high pressure mode is capable of substantially immediately taking up slack which develops in the outer belt, particularly in the horizontal feed portion thereof, with consequent prevention of spillage of load material, when the driving power for the dual belt conveyor-elevator is interrupted.