Unloading boomThe two belts feed two stern cross conveyors to a single loop belt elevator system to a 261 foot (79.55m)
unloading boom that can swing 90 degrees to port or starboard and unload at a rate of up to 5,413 tons (5,500 mt) of iron ore or 3,937 tons (4,000 mt) of coal per hour.
http://www.cslint.com/pdf_specs/SU-AtlanticSuperior.pdf (http://www.cslint.com/pdf_specs/SU-AtlanticSuperior.pdf)
From this side i copy the text.
http://www.boatnerd.com/pictures/fleet/atlanticsuper.htm (http://www.boatnerd.com/pictures/fleet/atlanticsuper.htm)