Abstract: A mobile bulk container for particulate solid matter having at least one gas permeable internal floor element for the transmission of air therethrough within a container to fluidize particulate matter resting on the floor, the latter element sloping downwardly toward one side of the container, a bottom discharge pipe for discharging particulate matter from the container, conduits for supplying air upwardly through the floor element, an air conduit leading from adjacent the top of the space within the container to the discharge pipe for transmission of the air from the container to the pipe, and a screw conveyor mounted within and along the bottom of the container at the side thereof below the lower end of the floor element ending at the discharge pipe for conveying the particulate matter out of the container while effectively providing therewith an air seal between the container and the discharge pipe.