Abstract: A portable slag beneficiating plant comprises lengthwise adjacent first and second stage sizing devices with an intermediate magnetically operated separating unit arranged to deliver separated metallics to the second stage sizing device and to deliver the separated non-metallic slag to a conveyor for remote accumulation. The first and second stage sizing devices in the slag beneficiating plant and the magnetic separating unit which incorporates a feed conveyor belt and the disposal slag conveyor are individually operated by hydraulic motor subject to the control of individual valves and supplied from a common source of hydraulic fluid pressure enabling the individual sizing separating and conveying devices in the portable slag beneficiating plant to be operated at different speeds and capacities manually variable continuously to expedite rapid and efficient handling of large quantities of slag by the plant.