One way to look at the Twin Cities as a setting for industry is from the perspective of the regional geology. Lake Superior and the Mississippi River allowed access to the state for early pioneers, and the presence of St. Anthony Falls at the head of navigation determined the locus of hydropower. Local mineral resources include limestone and sandstone bedrock, and sand and gravel deposited by glaciers.
The day begins in Minneapolis at the Mississippi River’s St Anthony Falls overlook in NSP Park, where abundant signage conveys the importance of the site. From here the tour proceeds west across the river to the heart of the former Minneapolis milling district at Mill Ruins Park (MRP) and Mill City Museum. After passing under James J. Hill’s famous Stone Arch Bridge (1883), you will see the tailraces of the First Street Canal, the City Water Company, and the North Star Woolen Company (the only local textile company). Water diverted from the river above the dam, having powered the turbines running the flour mills, rejoined the river here. Also visible are remnants of turbines from the former Midas Mill.
Mill Ruins Park, where flour-mill waterpower tailraces have been uncovered through archeological projects. Photo: National Park Service
After leaving MRP the tour proceeds downstream under the new I-35 Bridge, which replaced the one that collapsed in 2007, past the entrance to the Minnesota Library Access Center (MLAC—the University of Minnesota’s automated underground book storage facility), past the site of the Heinrich Brewery lagering caves, as well as WPA-era limestone quarries in the bluffs. We’ll stop at Lock & Dam No. 1 or the Ford Lock & Dam (an Ambursen concrete overflow structure).
Mississippi River Lock & Dam No. 1, aka Ford Dam. At center is the dam, with Lock No. 1 in the foreground. At the far end of the dam, across the river, is the Ford hydroelectric plant and, above that on the far side of the river, is the Ford Assembly Plant in the Highland Park neighborhood of St. Paul. The plant is now closed. Photo: Mulad for Wikimedia Commons.
At the east bank of the Mississippi, across the Ford dam, is the Ford Motor Company complex, including the Ford Twin Cities Assembly Plant, where Model T’s were assembled and, later, the Ford Ranger pickup truck. The plant closed in 2011 and is scheduled for demolition and reuse of the large site. Remaining, however, are two substantial power-generating facilities: the Ford hydroelectric plant and the Ford steam plant, both built to supply power to the auto assembly plant. We will tour the hydroelectric plant, which was constructed in 1924, preceding completion of the auto plant, and has remained virtually unaltered and operational since then. The plant houses four Westinghouse generators turned by four Francis-type vertical hydraulic turbines. (The nearby 1925 auxiliary steam plant, a Thursday tour site, is no longer in operation.)
The Metro Waste Water Treatment Plant in St. Paul. Photos: Bob Frame
We will proceed to the Metropolitan Waste Water Treatment Plant along the Mississippi at Pigs Eye Lake (hence the nickname, Pig’s Eye Plant) for a tour lasting 1.5 hours. Constructed as Minnesota’s largest Public Works Administration (PWA) project, and fully operational by 1938, it is supplied by the deep interceptor tunnels across the Twin Cities carved through the sandstone using hydraulic lances, as much as 200 feet below street level, serving both Minneapolis and St. Paul. Today it is among the nation’s largest treatment plants.
The Chicago, St. Paul, Minneapolis & Omaha RR swing bridge, viewed from the opposite side of the Mississippi in 1916, shortly after construction. Photo: Library of Congress
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Afterwards we will drive through Mushroom Valley, which for a century was the largest mushroom growing center west of Pennsylvania. Other related industries were beer lagering, blue-cheese ripening, and silica mining. The valley is today part of a park, where more than 50 sandstone cave entrances are visible through the vegetation. Finally we will drive by (Sorry no place for the bus to stop) the Omaha Road Railroad Mississippi River Crossing (Omaha Swing Bridge) before returning to the St. Paul Hotel.
Length of tour: 8 hours.
