Exploring Dock 4 was a very different experience, since it was almost all metal.
From the slip where grain boats would tie for loading and unloading, the unloader juts in a modernist-architectural way that is oddly visibly satisfying. Inside that white building is the retracted boat unloader, more or less a long and sturdy conveyor attached to a joint and crane motor. There used to be four loaders that looked like simple tubes with cranes and ropes attached hanging from this side of the elevator. All that remains of those is one fixture on the white building (not visible here) and the frame of one on the elevator proper, visible in the upper-middle of this image, to the right of the unloader apparatus.
Circa-1960s graffiti. Someone got their ass kicked.
Short-stack remains of mounts for rod and ball mills, if I was to bet. The concentrator separated junk rock (tails) from the copper and silver ore, to such a point it could be smelted.
What are we to do in an emergency?
The side stairs were worn smooth by use.
In front of a rust-welded Illinois rotary stoker is where the boiler-men made their mark. The last year I can make out is 1985.