It's weird seeing something that you have been through being seen from someone elses' perspective... the basement of the flotation is awesome... I can't believe you found the chemistry lab. i thought that was just a legend... we need to get together on this. (My damn schedule!!!)

Samurai

It's deceptively easy to find! It's right in the first floor of the building, almost directly across from the break room. One or two broken stairs. the ice was kind of hard to navigate. Many of the hillside portions of the mill are hard to navigate, as even with fresh batteries in my two d mag, it was like the light was sucked away.
Funny story; At one point on the machine shop floor, we noticed a stairwell that went into darkness. We just said "screw that" and went back downstairs. Ironically towards the back of the lab is said stairway. There is even a "hatch near the xray room which opens out "underneath" the building which is creepy. The back rooms of the building are the darkest and the ilmenite dust is in piles!
The top floor of the plant is great. I had my 35 mm with me with the wide angle lens, so hopefully got some shot from above. The cold wasn't a friend to this 16 year old camera as every other exposure the shutter decided to stay open indefinetly.
All my pics with the digital were crap, as the max exposure is 1/2 second. With flash you see nothing but darkness.
I'm convinced the garages are worth at least checking out, the fire station listed a "cafeteria" on the property. So those garages hold some secrets.
Bring a good light for the lab.. I wish it was super exciting. It's cool but everything is black, the autofocus on my camera hardly worked, I needed a Coleman lantern or something.
By the way given the cold we made a beeline straight for this building given the interest level.
Still Don't see how to get upstairs in the thin flotation plant.. that's best left for the summer.. camping!

There are a series of interior laddars to get from floor to floor in there, but not much to see.