Abstract: A hopper assembly has an upwardly facing mouth for receiving granular or powder materials, and structured and arranged for preventing or reducing the escape of material from the hopper. The assembly includes at least one resiliently flexible baffle extending obliquely downwards from a substantially fixed, generally horizontally extending top edge portion to a free edge portion. Another member may be provided having an edge portion in the vicinity of and extending substantially parallel to the free edge portion of the baffle. The baffle is arranged with respect to the other member such that if material to be received by the hopper assembly falls onto the baffle, the weight of the material tends to cause the baffle to deflect away from the other member, permitting the material to fall between the baffle and the other member. Being resilient, the baffle returns or tends to return to its original position.