About the Bridge
The bridge is part of US Highway 53, a 403-mile thoroughfare between La Crosse, Wisconsin and International Falls, Minnesota. The bridge spans 1,100 feet across the Rouchleau Iron Mine, named after prospector Louis Rouchleau. The mine began underground operations in 1893 and converted to open pit mining in the 1930s. By the time it closed in 1977, the Rouchleau Mine had produced 300 million gross tons of iron ore.
The mine pit below the bridge is roughly 3 miles (4.8 km) long and .5 miles (0.80 km) wide; its deepest point is 450 feet (140 m) below its surface, making it one of the deepest mines on the Mesabi Iron Range.
About the Bridge
To build the original Highway 53 the Minnesota Department of Transportation (MnDOT) in 1960 acquired an easement that allowed construction to take place on land that has significant mineral resources. As part of the lease agreement, MnDOT agreed to move the roadway if mining interests needed to access the land under the road. In May 2010, the landowner gave notice that the part of the land the highway was on would be mined at a near-future date. MnDOT negotiated a date of May 2017 to terminate the lease, and began studying alternative routes for Hwy 53. An environmental impact statement followed. By 2015, all necessary design and permitting had taken place, and construction began in November of that year.
Construction took place over two years, involved more than 100 construction workers and 165,000 hours, and cost $156 million. More than 10 million pounds of US-made steel beam and 800,000 pounds of rebar were used to build it. Impressively, construction was completed ahead of schedule, and the bridge was dedicated on September 15, 2017.
At 200 feet above ground, the bridge is among the tallest in the state. The Mesabi Trail, a cycling route, as well as motorized trails, cross the bridge. The City of Virginia’s water main also spans the mine pit in one of the longest high-density polyethylene pipes to cross a bridge.
Challenges in the design and construction of the bridge included extremely hard substrate that had to be blasted to create the eastern approach as well as the pilings for the supports. The project also included new or reconstructed interchanges at Minnesota Highway 135 and Second Avenue in Virginia.
In addition to MnDOT, project partners included the cities of Virginia, Eveleth, Gilbert and Mountain Iron, as well as St. Louis County. Kiewit International served as construction manager/general contractors, with major contracts awarded to Ulland Brothers, KGM Contractors, Danny’s Construction Company, Veit, Parsons Electric and Hoover Construction.