Abstract: An apparatus is provided for the removal of oversized contaminants from particulate material the is particularly suitable for the removal of contaminants from low density, high surface area particulate materials. The removal of contaminants is accomplished during the transfer of the particulate material from its storage or transport container to a receiving container. The apparatus comprises an assembly having a weir, a trap disposed adjacent said weir, a screen o for separating particulate material from oversized contaminants, a baffle, and an opening through which particulate material will flow freely. The weir has a weir trap flange extending laterally from a weir wall. The trap is configured to capture contaminants if the container to which the assembly is secured is maneuvered to initiate the flow of the particulate material from the container to the receiving container. When so maneuvered, the lowermost portion of the trap in the proximity of the flow of the particulate materials subtends the weir.