Tunnel Mill, 1871 Engineering Marvel Near Spring Valley

SPRING VALLEY – From the 1850s through the 1870s, Fillmore County had the highest quality and greatest number of grain mills ever built in Minnesota. Yet one, Tunnel Mill north of Spring Valley, stood out from the abundance of area mills due to a unique system to power its operation created by an engineering marvel that was accomplished without the aid of modern instruments.

Fillmore County’s geological advantages of rolling agricultural lands and quickly cascading creeks and rivers led to the great concentration of mills, particularly in the southeastern edge of the county where more than 150 mills were constructed between 1855 and 1900 and in the northwestern corner where more than 50 mills were built during the same period.

However, Tunnel Mill owner Johnson Stout wanted to improve upon those unique geological advantages so the industrious owner blasted a tunnel through a bluff to create a more rapid flow of water to power his mill in 1871, an effort some called “Stout’s folly” because they didn’t believe it could be done.

This was the only known mill in the state to be powered in such a manner and represented a unique and rather ingenious engineering solution to an age-old problem, according to state historian Thomas Lutz.

A group of men stand on top of the Tunnel Mill intake in this undated photo. (Photo provided by Spring Valley Community Historical Society) The mill prospered for decades. Although not in use today, the site is on the National Register of Historic Places and is currently a craft smithing center.

Grist mills once common, especially in Fillmore County

North America was once dotted with grist mills in the 1840s through the end of the 19th century. These water-powered mills were situated next to a swift river where the current from that river turned the water wheel, which turned the heavy stones, which ground the corn into cornmeal or the wheat into flour for baking and cooking.

Most towns in southeastern Minnesota had active grist mills in the 1850s. Eventually, small-town grist mills struggled to stay afloat due to increasing competition from Minneapolis mills and diversification away from wheat by southeastern Minnesota’s farms, according to a historic marker for the Forestville Grist Mill on the south bank of the Root River near the picnic shelter at Forestville/Mystery Cave State Park.

Before the development of the modern roller milling technology in the 1880s and 1890s, Fillmore County superseded in quantity and quality even the world-renowned mills of St. Anthony Falls at Minneapolis, according to a 1975 National Register form submitted by Lutz, who was with Historic Sites Survey and Planning of the Minnesota Historical Society.

The reason Tunnel Mill was added to the National Register is because it is the last surviving mill in the important “western concentration” of grist mills in Fillmore County, Lutz noted.

A satellite view shows the winding Bear Creek along County Hwy 1, north of Spring Valley. The Tunnel Mill was built in the vicinity of where Tunnel Mill Crafts exists today. (Satellite imagery by Airbus, courtesy of Google maps, ©2026) Engineering success despite lack of tools

Stout was 24 when he came to Fillmore County in 1854 from Michigan in search of good locations for grist and saw mills. He built a sawmill on Bear Creek in 1856 and then a stone grist mill in 1866. A few years later, he started on his most noted project, Tunnel Mill.

The mill was a large two-story frame structure set upon a basement of solid masonry. Stout ran the mill in the conventional way for the first few years, but he decided to improve upon the leisurely water flow of Bear Creek to create a swifter, sustained current to keep the water wheel spinning as fast as a windmill.

At a point 600 feet west of where the mill stands, Bear Creek in its eastward course strikes a high rocky bluff, causing it to run south, then east, and then northwest a distance of over a mile and a half, in an oxbow shape, to accomplish a distance of just 700 feet, according to an 1873 newspaper article in Spring Valley’s Western Progress. The bluff between these two points is 90 feet above the water level, heavily wooded and composed of solid limestone rock.

The industrious businessman came up with an idea to improve his operation by capitalizing on the natural advantage of the site. Stout decided to tunnel through the bluff, creating a 27-foot drop in the creek bed that would provide enough velocity to turn his water wheel while also remaining free of frost.

Stout had his detractors, according to an Austin Daily Herald article written by Harold Severson in 1950. The numerous skeptics in the area openly ridiculed the project as it was a momentous undertaking.

Two unidentified men stand near the head of Tunnel Mill. (Photo provided by Spring Valley Community Historical Society) Stout’s plans called for creating a 4-foot wide by 6-foot high tunnel with a length of more than 600 feet through the bluff. He hired four men during what local old-timers describe as “one long, cold, hard winter” to construct a tunnel shortcutting the creek and supplying the water power, according to Lutz’s form. Local histories claim the tunnel took the better part of a year to build using three tons of powder to blast through the limestone bedrock.

John Halbkat, one of Spring Valley’s early historians, related that his father was one of four men hired by Stout. He got up at 4:00 a.m., hitched up his team of oxen, and drove to the mill site. He worked until dark, then drove back home — all for the princely sum of 45 cents a day, which included use of his oxen, according to a 2015 history written by Mary Jo Dathe-Oss, a Spring Valley historian.

G. W. Perry, a stone mason and cooper barrel maker, was also on the crew. His grandson, F. J. Perry of Rochester, told Severson in 1968 when he was with the Post-Bulletin that two teams working from opposite ends “dug with hand labor and black gunpowder, aided only by a compass, carpenter’s level and a string for alignment.”

A natural seam in the rock was used on the western side of the work. The very narrow seam varied from a direct line when near the center of the bluff, so another excavation was commenced from the eastern extremity to intercept it.

When the workmen on opposite sides neared each other, they could readily hear their opposite companions at work, and many skeptics said they would pass without meeting, noted the Western Progress article. However, when the parties met, the measurements were so accurate that when each drilled a small hole in the center, they came within six inches of each other.

No scientific appliances were used further than to get the level, the work being conducted entirely by the eye and by careful measurement, according to the Western Progress.

Severson noted in his Herald story, “For unskilled tunnel diggers, it was a monumental achievement of engineering skills as Stout and his men lacked surveying instruments.”

Tunnel Mill a busy place for decades

The Western Progress story noted that the mill had two waterwheels, an 18-inch Leffel and a 15-inch Beloit. The Beloit was used for custom work, grinding 200 bushels every 24 hours, while the larger wheel, used mostly for feed, was grinding about 300 bushels in the same time. Back of this mill, a tail race had been tunneled 100 feet in length, making the entire tunnel 700 feet long.

A dam was created near Tunnel Mill to create a pond as shown in this hand-colored photograph by E. M. Lloyd. (Photo provided by Spring Valley Community Historical Society) The shafting and gearing of the mill were manufactured and put in by W.H. Lloyd of the Spring Valley Foundry. “The workmanship of the part of the mill is so fine as to excite the comment and admiration of all who visit the mill,” stated the Western Progress article. “So true and perfect and so quiet does the machinery run, that when everything is in full motion and the mill grinding at its fullest capacity, common conversation can be carried on in any part of the mill without effort or extra raising of the voice.”

The Progress article estimated the value of the mill at about $10,000, of which $4,000 was expended in digging. The firm of Stout, Hammer & Co., which consisted of Johnson Stout, L.C. Stout, and T.J. Hammer, owned the mill.

For many years, Tunnel Mill ground feed and flour for neighboring farmers, acting as somewhat of a community center for people to gather and exchange stories while their grain was ground. As was the case with many neighboring operations, Stout added a shed addition in 1881 as a sorghum mill, which produced 2,000 gallons of molasses in its first year of production.

F.A. Leonard purchased the mill in 1892. Frank Boland took it over in 1913, and in 1921, he did repairs on the tunnel and added machinery, according to an ad in the Spring Valley Tribune. It continued operations into the 1930s after Boland’s son, Donald, took it over.

Mill gets renovation in recent years

John and Carol Adams of Rochester purchased the site in 1982 from Lawrence Maus, a self-described “history nut,” who had bought it from Stafford Hansen in 1972 with the intention of restoring it to its former glory.

The late John Adams, with beard, observes one of the demonstrations at Tunnel Mill. His wife, Carol, still holds gatherings and classes at the site. (Photo provided by Spring Valley Community Historical Society) The Adamses had a major project on their hands: the collapsed roof was replaced; new flooring was installed on both the main and upper levels and they undertook dozens of other refurbishing projects to make the structure livable. Maus, who originally intended to make it his home, had previously tuck-pointed the foundation, insulated the structure and finished upgrades throughout.

Dathe-Oss wrote in 2015 that the wonderfully restored mill has space for eight sleepers upstairs and more overnighters in two handsome gypsy wagons on the grounds. The mill’s main floor boasts a pot-bellied stove, ample wood box, a lovely old cook stove, an eight-foot sturdy table and benches for dining as well as quilt and craft projects, hand-made cupboards to house dishes and appliances, and the big glass-topped counter under which one can see below the original flume.

Outside is a buried but visible grindstone, a shelter for several forges for blacksmithing, a new barn for special events, a smelter and incredibly intricate metal gates.

Once the renovation was completed, the two started holding workshops at the site for blacksmithing, metallurgy, quilting and other skills throughout the summers. John died in 2018, but Carol still schedules events at the site.

Experience ‘Tunnel Mill’

Upcoming events, hosted by Tunnel Mill Crafts, include the annual Fall Mill Gathering Oct. 9-11 with people on hand to demonstrate blacksmithing, make candles, paint a barn quilt block, make a wind chime and create other items.

Classes in October include ones on relief wood carving, blacksmithing, candle-making and painting a barn quilt block.

Check out all their events, find preregistration forms and sign up online on the Tunnel Mill Crafts calendar page.

Contributor David Phillips lives in Spring Valley. He is a writer, photographer and editor who worked with various newspapers for 45 years until retiring as publisher of the Bluff Country Newspaper Group in southeastern Minnesota in 2020.

Tunnel Mill, 1871 Engineering Marvel Near Spring Valley

Comments