Qualla: Lake Vermilion-Soudan Underground Mine State Park

Lake Vermilion-Soudan Underground Mine State Park: Introduction

Thu, 05 Feb 2026 00:00:00 GMT

Photo credit ShakataGaNai, CC BY 3.0. Visitors step into a 1924 electric mine cage and drop nearly half a mile straight down. At level 27 -- 2,341 feet below the surface of northern Minnesota -- the air is cool and still, the rock walls are 2.69 billion years old, and cosmic rays barely penetrate. This is the Soudan Mine, the oldest and deepest iron mine in Minnesota, where prospectors once pulled hematite so pure it contained more than 65 percent iron, and where, decades after the last ore car rolled, University of Minnesota physicists built detectors to search for neutrinos and dark matter. The mine is now the centerpiece of Lake Vermilion-Soudan Underground Mine State Park, a National Historic Landmark on the south shore of Lake Vermilion in the Vermilion Range.

Image: ShakataGaNai | CC BY 3.0

Lake Vermilion-Soudan Underground Mine State Park: Gold Seekers, Iron Finders

Thu, 05 Feb 2026 00:00:00 GMT

Photo credit James St. John, CC BY 2.0. The prospectors who arrived in the late 19th century were looking for gold. What they found was far more valuable to an industrializing nation: extremely rich veins of hematite, the iron ore that would feed the blast furnaces of Pittsburgh and Chicago. An open pit mine began oper...

Image: James St. John | CC BY 2.0

Lake Vermilion-Soudan Underground Mine State Park: Deeper Than Daylight Reaches

Thu, 05 Feb 2026 00:00:00 GMT

Photo credit James St. John, CC BY 2.0. In the 1980s, the University of Minnesota recognized something valuable about the Soudan Mine beyond its ore: depth. At 2,341 feet underground, the cosmic ray rate drops to a whisper. That silence made the mine ideal for physics experiments that require extreme shielding from bac...

Image: James St. John | CC BY 2.0

Lake Vermilion-Soudan Underground Mine State Park: Fire in the Shaft

Thu, 05 Feb 2026 00:00:00 GMT

Photo credit James St. John, CC BY 2.0. On the night of March 17, 2011, fire broke out in the main shaft at the 25th level. Responders smothered it by pumping 70,000 gallons of firefighting foam into the lowest levels, filling the 27th level from floor to ceiling. The underground physics laboratory lost power but remai...

Image: James St. John | CC BY 2.0

Lake Vermilion-Soudan Underground Mine State Park: Two Parks Become One

Thu, 05 Feb 2026 00:00:00 GMT

Photo credit James St. John, CC BY 2.0. For years, Soudan Underground Mine State Park stood as its own entity. Then in 2010, the State of Minnesota purchased about 3,000 acres from U.S. Steel along the south shore of Lake Vermilion to create a separate Lake Vermilion State Park. The new parkland included the Stuntz Bay...

Image: James St. John | CC BY 2.0