A conveyor assembly is provided for use with a mobile vehicle. The conveyor assembly includes a conveyor module. The conveyor module includes a first roller assembly. The first roller assembly includes a first rotatable roller body and a second rotatable roller body. The first and second roller bodies are interconnected to each other in such a manner as to share a first rotational axis yet be at least substantially rotationally independent of each other, such that each of the first and second roller bodies can rotate without causing or interfering with rotation of the other of the first and second roller bodies.