A dewatering conveyor system for dewatering chunks of petroleum coke or the like material which is mixed with large volumes of water, wherein the conveyor employs lateral drag bars, the top flight of which conveyor slides forwardly on a screening deck having dewatering screens, and the bottom flight of which conveyor slides rearwardly on a sluice deck underlying the screening deck, wherein a major portion of the conveyor rearward of its discharge end is contained by tail end wall means and side and bottom wall means which can contain large volumes of coke and water, wherein, for handling large volumes of water the discharge end of the conveyor is elevated, e.g., up to 20 ft. or more above the tail end of the conveyor such that water dropping thru the screens will run down toward the tail end of the conveyor and leave the discharge end above the water line, and wherein a drain port is located thru the bottom wall means at a tail end portion thereof.