a side wall and cover system for conveyor assemblies for containing particulates during conveyor operation . the invention utilizes rollers that are centrally positioned on corresponding support members which support a pair of angled wings the roller sides . these angled wings support impact bars that are aligned in the direction of conveyor movement and support a troughed conveyor belt . side walls are secured to the angled wings and include an upper surface to which a cover is releasably secured . seals and gaskets are positioned between confronting surfaces of these components to prevent dust particulates from emanating between the surfaces . the side walls permit additional conveying volume at the sides of the conveyor and a roller hanger is also provided to facilitate the servicing of such rollers without the need to lift the conveyor belt . plural side wall / cover systems can be releasably secured together using side wall - projecting flanges and interlocking tabs .