This is quite a place! This is a huge and strange mine. The sound of underground rivers far below, 4 ft boreholes going hundreds of feet through the mountain into the unknown, elevators, hoists, slushers, rusty ladders, pipes, stalactites, underground offices, workrooms, explosive lockers, and strange experimental testing equipment, all spread across nine levels and miles and miles of drifts. A full day of exploring is just getting started in this place. We have visited this mine a few times and have still not seen all of it.
One of the more unusual things we came across here are some offices of the Dept of Defense ICBM Deep Basing program and experimental test equipment. The ICBM Deep Basing program was a project to test the feasibility of locating Peacekeeper (MX) Missiles deep underground to give them the ability to survive a nuclear attack and launch a counter-strike. The test equipment appears to be a series of steel pipes where pressurized freon 113 was injected into the rock and the temperature transfer was checked by thermal sensors drilled into the rock nearby. What exactly they were doing is unknown, but I am guessing they were testing the character of the rock here for a possible deep basing missile site.