After purchasing our tickets online yesterday we headed this morning over to the state park just east of Tower, Minnesota for the Soudan Underground Mine Tour where we had the privilege of riding in a crowded cage down to Level 27, the deepest level worked before the mine closed in December 1962. We then took an electric train another half mile where we disembarked and climbed a 36 step spiral staircase up to the stoup, the area where the miners worked in near darkness lit only by candles, then carbide, and finally battery head lamps. The cut and fill process they used here involved blasting rock from the ceiling, removing the ore, and using the waste rock to raise the level of the floor. Although it produced 15.5 million tons of high quality iron ore over it’s eighty years, this “Cadillac of Mines” eventually fell victim to new technologies in which it was more cost effective to use lower quality ores obtained from open pit mines in the production of steel. Shortly after it closed the mine, US Steel sold the mine and surrounding property to the State of Minnesota and by 1965 the state park had opened with tours to share the history of this part of the Industrial Revolution with all of us who are interested. Another part of the history of the mine is that it is the site of a former University of Minnesota underground physics laboratory. We didn’t take the opportunity to tour the lab todaynbecause we always have to save something for the next time, but we did do some of the self-guided surface tour as well as go in search of a geocache that led us to some gorgeous banded iron formation rock on the surface.