Abstract: A portable storage tank apparatus includes a tank shell mounted on wheels to be towed to a work site and adapted to be supported at the work site store granular material. An outlet opening has a gate to discharge stored material from the shell. A front loading conduit has an interior end at a top portion of an interior of the tank shell, and an exterior end located near the front end of the tank shell, and a rear loading conduit has an interior end at a top portion of the interior of the tank shell, and an exterior end located near the rear end of the tank shell. The exterior ends of the loading conduits are adapted for connection to a discharge pipe of a pneumatic conveyor to receive an air stream carrying granular material. Multiple tank compartments and a pneumatic conveyor unloading circuit can be provided as well.