Some views of the hoist equipment which is used now to take visitors at 10 MPH down to a half mile below the surface, 688 feet below sea level. Two cables are wound around the drum, one feeding off the top and one on the bottom so that one set of cars is coming up while the other set is going down. The large dials indicate the position of each car.
We're getting settled on the small train that will take us three quarters of a mile to the iron ore. It's Ken, Pat, Kevin, Pat and Charlie. At this location is something I'd really have liked to see. It's a brand new neutrino detector, built in the year 2000. Fermilab in Chicago will be sending a beam of neutrinos through the earth's crust to this detector as part of a physics research project.
Off we go, down the drift tunnel. The train is now run on batteries, but when the mine was active it ran on the 72 volt conductor that can be seen running below the insulator.
Here we are, at the 27th level. We're now 1-1/4 miles from the surface, given the ride down and the train ride to the ore vein. The ore is hematite, which ranges up to 68% pure iron oxide. It's so pure it can be welded. Surrounding the ore is jasper, which is why you won't see any supports. They simply aren't needed. This was one of the safest underground mines in existence.
On the left, a view of cut and fill mining in practice. The miners would blast the ceiling down, which is the ore in the vein, then dump the high grade ore down to a lower level where the train took it to the skip cars which haul it to the surface. Any fill and rubble is allowed to build up the floor so that the vein is worked in an upward direction until it comes close to the level above it. On the right is hematite and jasper. Which one do you send up to the boss?
Back up on the surface, free from the risk that the oceans of the world will fill the mine with salt water, we see that the elevator shaft runs at an angle so as best to follow the vein of ore as it runs down.
We celebrate with lunch at Tower, site of Minnesota's coldest recorded temperature, at -60 degrees Fahrenheit.