Sweat threatened to break beneath my yellow hard hat as I stood in an open-air shelter, the only shade on a sunny hilltop outside the entry to Minnesota's first iron ore mine. Just in time, a door swung open and brought nature's air conditioning with it. That blast of cool air, transported here from a half-mile beneath the Earth's surface, fanned out of a 90-year-old metal-walled cage, trading places with the 10 humans who went in. We were on our way down, 27 stories underground, in the footsteps of the miners who took this cage to work every day, at what is now Soudan Underground Mine State Park.
"It's gonna be fast," our guide said as the doors clanged shut. Then, we dropped.
On the surface, Minnesota is dotted with lakes and furred by forests. In the cities, skyscrapers and cathedrals soar, suburban tracts meander. But if you look past the visible natural and man-made wonders of our state — look beneath them, actually — you'll find a whole other Minnesota underground.
In northern Minnesota, the Iron Range is still home to an active mining industry that has transformed both the cultural and topographical landscape of the region since the late 19th century. In southeastern Minnesota, cave systems that began forming hundreds of millions of years ago are untouched windows into our planet's past.
The two areas couldn't be more different, geologically: The ore deposits Up North are valued for their strength, while the limestone in the south is so soft that flowing water dissolved it into caverns. But both subterranean worlds are road maps to the history of the planet, evidence that the Earth is far greater than anything man can make out of it.
Mines of the Iron Range
The northern landscape is punctured by open pits, some still active, some filled with crystalline water. The lakes are bracketed by red hills of "overburden," leftover dirt denuded of its deposits and reclaimed by greenery. These craters are so plentiful in this region, it feels like you're always at the top of something, like standing at the edge of the Grand Canyon. Visitors curious about mining have a number of options, including tours of a working mine or one that closed in 1978, as well as overlooks of massive man-made canyons.
The Soudan mine, about 20 miles southwest of Ely, supplied some 15.5 million tons of ore to U.S. steel production in its life span of 80 years. Its working conditions were relatively safe, dry and a comfortable 51 degrees year-round, earning it the nickname "The Cadillac of Mines" among workers. Shuttered in 1962, it lives on as the only underground mine in Minnesota to offer tours below the surface.