I found a historical photo of this room showing 10-foot high machines with wires hanging by the mile from looms and schematic charts.
Windows provided the 250-some workers with fresh air and light, and helped to keep flour dust from building up in the air, helping to prevent explosions. Today, machines control air flow better without windows, so they were bricked.
Here, the concentrated gold (and silver, and zinc, I would guess) would be loaded into trucks bound for the smelter.
A look down the 1950s foundry building, moments after sunset.
The newer tunnels were fitted with these fluorescent lights, although some skylights (block glass embedded in skywalks) let in some natural light during the day.
This drying house was full of ventilation ducts, broken scales, and insulated carts to haul powder around the line.
This volume gauge could be read from 30 feet away, which is useful when the control panels and valves are that far away.
Scrappers infamously gutted the factory, but this one green conduit going from the sintering floor all the way to ground level seems to have been spared.
This used to be the main entrance of The Orpheum, before Orpheum Garage on Superior Street was converted into a new entrance.