Schieks Cave—aka Farmers & Mechanics Bank Cave—is the largest cave under downtown Minneapolis, Minnesota. The otherwise excellent chapter on the cave’s history in the 1980 NSS Guidebook does not specify exactly when, or by whom, the cave was discovered. That information, however, is contained in the following newspaper clipping, slightly abridged, from the Minneapolis Tribune, August 23, 1931. Schieks Cave was discovered by city sewer engineer Carl Illstrup in 1904.
As background, the reporter, Fitzsimmons, describes the “makeready” work that led to Minneapolis getting plugged into the giant interceptor sewer feeding the Pig’s Eye sewage treatment plant, which would become operational in 1938. Specifically, he deals with the construction of the Second Avenue tunnel and the Minnehaha trunk line. No longer would raw sanitary sewage be discharged directly to the Mississippi River.
Fitzsimmons is the most enthusiastic sewer reporter to deal with Minneapolis. He waxes poetical about “the beauties of the sewer system.” He describes Illstrup as “the ruler of this fantastic world.” The discovery of the cave in 1904 is presented as the highpoint of Illstrup’s life.
Illstrup’s physical description of the cave is of interest. Firstly, having visited this sandstone maze cave several years ago, I find it difficult to conceive of its shape as “an inverted bowl.” The “curtain of water 30 feet in width” sounds like the ceiling spring now known as “Little Minnehaha Falls.” The 20-foot deep sinkhole in the floor of the cave was evidently a piping channel draining to the Fourth Street tunnel, as it helped to “blow the flooring off the sewer.” The cave behaved hydrologically as it does today, in the sense that it fills with water (or sewage) when the adjacent tunnel is surcharged, then releases it back afterwards. In addition to sewer gas, the workers are said to have encountered gas pockets in the St Peter Sandstone itself.
But this clipping is also of interest as a document in the sociology of work. Rarely has sewer work been portrayed as such a romantic endeavor. Fitzsimmons points a stark contrast between adventure and toil, between beauty and death, in the sewers. For those interested in pursuing this subject further, Donald Reid’s 1991 book, Paris Sewers and Sewermen: Realities and Representations, is an excellent starting point.
This glamorization of sewer work, ironically, was made possible by mechanization. Although the method of tunnel advance is not made explicit, Fitzsimmons mentions drilling. (The hydraulic jetting method was not introduced locally until 1934, according to the engineer Charles Payne.) While the “miniature railroad tracks” laid through the tunnels during construction are nothing unusual, the “barge line” through the sewers—used to haul construction materials—seems unique. I have braved the Fourth Street tunnel myself—a chest-deep river of raw sewage—and I can tell you that the notion of poling up this gray, turbid stream like a Venetian gondolier, “loaded with materials,” seems far fetched. Perhaps there was a different flow regime back then!
Burrowing Workers Risk Lives for Public’s Health
Hidden Perils Braved Every Day by Crews in Tunnel Network
Men Who Build and Maintain Sewers Adventurers as Soon as They Go Below Surface to Their Work.
By Robert J. Fitzsimmons.
Far beneath the surface of Minneapolis, where the sunlight never reaches and the bustle of modern traffic goes unheard, there is a strange world astir. As worlds go it’s a pretty young one, since it started in 1872. But the laborious manner in which it has groped out from year to year, overcoming great difficulties, gives it a certain sort of antiquity. Just now it is invested with a fresh purpose and is striving with renewed impetus to get things done.
Its inhabitants are interesting creatures—plain, everyday men when they are at the surface, but adventurers when they have climbed below and accepted the hazards of their bold calling.
It is a world of tunnels, shafts, drills, narrow-gauge tracks, dinky cars, rip-rap, brickwork, strings of lights—and of men on the job. On a job that they don’t hope to have done before 1940, when they will take up another one.
It is a world also of hidden dangers, the lurking treacheries of caving dirt, or the menace of onrushing waters, or the lethal breath of deadly gases.
It is a world that calls for more than a passing measure of skill, devotion to duty, and susceptibility to a queer kind of romance.
Finally, it is a world so snugly tucked away that only a comparatively few persons know of its existence, or extent, or age.
This world comprises the system of tunnels that have been dug, that still are being dug, to give Minneapolis its sewer system.
That word sewage may have a commonplace sound. It may conjure up only distasteful and unpleasant thoughts. Yet that is because the work that is going on under ground isn’t generally understood.
Carl J. Illstrup, city sewer engineer, who may lay claim to being the ruler of this fantastic world, finds plenty to fire the imagination and to challenge the best efforts of himself and his workmen. At present, he explains, they have embarked on the “makeready” work for the construction of a joint system that will unite Minneapolis and St. Paul in a huge sewage disposal project. So well has the work of the past been done that the projected system ties into the old. The tunnels will connect up with a giant interceptor sewer which, in turn, will carry it to a huge plant for treatment.
A figure or two may show what already has been done.
Minneapolis…tunnels, which if laid end to end, would be the longest single tunnel in the world—685 miles…
Mr. Illstrup has been the guiding destiny of the sewer system since 1881 and in that time has come to be recognized as one of the outstanding authorities on sewer engineering in the nation. During that time also he has found his job the most fascinating in the world, rich in adventure and achievement.
He likes to think of his domain beneath the city streets as something more than its commonplace name implies, perhaps a hidden parkway at which future archeologists will marvel in discovery or as a setting for the exploits of a local Jean Valjean, whose adventures in the sewers of Paris immortalized them in the realm of literature.
Masterpieces Hidden in Subterranean Galleries
The thrills of Les Miserables, if in more conservative and mortal measure lie beneath each city manhole, he maintains, and a challenge will produce a venture as exciting, outside the realm of fiction, as the uninitiated can withstand.
Perhaps it would seem exaggeration to exploit the beauties of the sewer system but nature’s brush has painted and her hands have sculptured many hidden masterpieces to be viewed only by those whose daily tasks take them to her subterranean galleries…
As evidence he cited the Second avenue tunnel, extending from Fourth to Eighth street, recently completed.
For months since last October dingy red shanties on the avenue, mobile offices of the foremen, marked the activity as a sewer project. They, for a time, excited comment and passing curiosity but only a very few of the curious ventured near to ask a question or to peer into the yawning depths of an apparently bottomless shaft.
Bore Through Sandstone 120 Feet Underground
It was just a sewer. Yet beneath it was a major mining project carried on without the slightest interruption of activities in a busy loop.
Boring through the sandstone, 120 feet below, was a crew of master workmen who daily pushed their task a few feet nearer to completion. For months they toiled, operating in that half world, a railroad, a barge line, an electric plant, pumps, fans and the various other paraphernalia necessary to the project, while the rest of the world walked by the hole at the surface and abstractedly wondered what was going on.
The Second avenue tunnel is only a tiny sample of the work that has been going on beneath the floor of the city for many years and not comparable in size or capacity to the Minnehaha trunk line, work on which is now nearing completion near France avenue. When the latter is finished it will stretch from France avenue across south Minneapolis along Minnehaha creek to its outlet at Fifty-second street and the river. It has been underway since 1923 and includes one mile and one-half of a tunnel 13 feet in height and 11 feet wide which is now in use.
Function to Serve as Relief Artery
But the Second avenue tunnel required as much if not more skill because it was carried on in the busiest part of a busy city…
…a crew of men poled a row boat loaded with materials through the Fourth street tunnel from the river…
Miniature Rail Tracks Are Laid
This latter crew bored and dug through 50 feet of glacial drift, blasted through 30 feet of limestone into the sandrock and finally drove the shaft to the 120-foot level where with mathematical accuracy a few weeks later a crude tunnel from Fourth street was broken through.
Miniature railroad tracks were laid along the tunnel, a lighting system was installed, blowers to keep the air unpolluted, and the work went on. Water seepage from the shaft and from the tunnel soon developed a fast-flowing stream which covered the tracks and cascaded into the Fourth street tunnel, a drop of some five feet.
Hip boots became the fad in footwear and the workmen were once again forced to take to the boats to carry materials to and fro. A barge line was improvised and the skippers poled their craft through the underground channel against a heavy current that threatened at all times to sweep them unceremoniously over the falls into the Fourth street tunnel…
As the shaft was cased with brick, however, much of the seepage disappeared and the railroad was pressed back into service. Forms were made to seal the walls of the tunnel with cement and the hand-propelled freight cars rumbled back and forth on a busy line. Cement was piped down the shaft at Seventh street and distributed to the workmen in tiny carload lots.
To properly appreciate the difficulties under which this crew worked it must be pointed out that the completed tunnel has only five and one-half feet in height and less than four feet wide, a horseshoe shaped passageway in which to stand erect was impossible.
Added to these conditions must be listed the peril of sudden storms—a constant hazard on all sewer projects and one that only last year cost the lives of two workmen who were trapped. A perfectly dry sewer is almost certain to become a raging torrent during a sudden rainfall and for this reason the department constantly keeps a lookout posted at the surface.
A pistol shot will bring the crew running to the shaft to begin the scramble to the top. Some straddle the rope pulley and bucket which serves as an elevator for materials and others scale the sheer ladder of the shaft, a climb guaranteed to tax the courage and strength of any but the workmen. To them it is a commonplace occurrence, a little sport that precedes and climaxes each day’s work.
Pockets of Gas Form Another Danger
There are other dangers, too, hidden in sudden pockets of gas opened during drilling and in underground lakes, usually small but frequently big enough to inundate the restricted area in which a crew must work.
These occasions, however, provide the real adventure of sewer engineering and frequently reveal the beauties which Mr. Illstrup maintains are the secrets of the earth.
One of his favorite anecdotes and incidentally an experience in which he nearly lost his life concerns the discovery of a cavern near the Second avenue tunnel. At the time it was both a cavern and a lake and its discovery in 1904 was brought about by an upheaval in the floor of the Fourth street trunk sewer and the discovery by workmen of gas pockets while they were building a connecting tunnel under the old Northwestern bank building.
Mr. Illstrup decided to investigate and by crawling through narrow fissures and crevices in the ground, at times nearly overcome by gas, he found the cave located under what is now the Hodgson building.
Cave Shaped Like an Inverted Bowl
It was shaped like an inverted bowl and filled with water. “Dripping from the ceiling at one place,” he recalls, “there was a regular curtain of water 30 feet in width. The water in the middle was 20 feet deep at one point and tapered down to inches at the shore line. It was a beautiful sight but we had to drain it to remedy the troubles in the Fourth street tunnel. They were caused by water pressures which would rise when the cave was full and the force escaping through the various fissures and crevices would blow the flooring off the sewer.”
The experience is the outstanding one of many that Mr. Illstrup has experienced and perhaps that and like experiences lend a certain air of romance and adventure to sewer work.
Regardless of what prompts the calling of the men who carve the city’s sewer pathways their present job is making ready for the construction of the joint disposal system. The Second avenue tunnel has been completed and within the next few weeks the last workman will climb out of the Minnehaha trunk line. The “makeready” work will have ended.
Minneapolis will be ready this fall to begin the job of building an interceptor and hooking in the outlets.