Abstract: A materials handling system is disclosed which includes a pneumatic conveyor which feeds material onto a series of belt conveyors. The pneumatic conveyor includes a vertically movable nozzle for sucking up the material to be conveyed. Power is supplied to one of the belt conveyors from a power source and through that conveyor to the conveyors upstream of it. The pneumatic conveyor is connected to the first of the belt conveyors of the series so that it receives a signal indicating whether the first belt conveyor is powered. In the event that the signal received by the pneumatic conveyor indicates that the first belt conveyor is not powered, and the pneumatic conveyor is set for automatic operation, the nozzle is automatically lifted. Lifting continues for a predetermined period so that the nozzle is lifted clear of the material. Only when power is restored to the first belt conveyor, and this is signalled to the pneumatic conveyor, can the nozzle be lowered again.