Rediscovering Schiek's Cave
-Freak
First, some history.
The history of Minneapolis's underground
begins long before human settlement, with the formation of alternating
sandstone and limestone layers close to the surface of the Minnesota prairies.
The existence of a relatively thick but loose sandstone layer topped by
a thin, hard limestone cap created the potential for large, stable, and
rapidly-formed cavities just below the surface. The indigenous inhabitants
found many natural caves along the banks of the Mississippi, some formed
by floods carving out sandstone banks, and some formed by springs leaching
down through the sandstone and washing away the soft material. White settlers
found this geology particularly useful for digging water raceways, sewer
tunnels, and storage caves, which soon honeycombed the more developed sections
of riverbank as the Twin Cities developed.
Until the turn of the century,
the city of Minneapolis relied on a number of private septic pits and a
few short riverfront pipes for its sewage needs. Mill tailraces often served
dual use as sewage and hydropower outfalls, but reached only limited areas.
Nearby St. Paul began carving an intricate labyrinth of sewer tunnels beneath
its streets in the late 1800s, but Minneapolis was burdened with a much
thicker limestone layer which made access to the deep sandstone more difficult.
The solution, designed by city engineer Andrew Rinker, was to construct
a very large, high-volume sewer interceptor tunnel beneath the heart of
downtown, and connect homes and businesses thorough a network of deep side
tunnels and shallow feeder pipes. While nowhere as extensive as St. Paul's
6'x3' sandstone and brick network, the North Minneapolis Tunnel, or NMT,
was a much larger and deeper tunnel, with an inside diameter of 9.5ft,
a vaulted brick and stone ceiling, and a flattened invert (floor). Feeder
tunnels stretched down several major downtown streets in a tree branch
pattern, with dropshafts from shallow pipes penetrating the limestone cap
to connect to the deep system. Excavation was done both by hand tools and
by hydraulic pressure, the sandstone could be carved out simply by blasting
it with water jets and allowing the sludge to ooze out into the Mississippi.
While constructing the NMT around
1900, work crews broke through into several natural cavities beneath downtown
and elsewhere. While most were relatively small voids, the one beneath
the then Farmer's and Mechanic's Bank was quite large, spanning half a
block, and reportedly contained many flowing streams, pools, and a waterfall
dubbed “Little Minehaha Falls” pouring from a ceiling fissure. The NMT
was continued through and just below the cave,
with an access shaft and door added. Reports from the period are quite
sensationalist while being vague on actual details, so the original condition
and early history of the cave are difficult to determine. At some point
prior to discovery, an artesian well pipe had been driven through the cave,
and leaks from this well were considered a possible explanation for the
cave's formation. Sometime before 1904, a shaft was bored to the surface
with a ladder and hexagonal sewer lid installed, and a sewer connection
from the F&M bank was passed through the cave and into a tunnel leading
to the NMT. In the mid 1920s, the city of Minneapolis quietly commissioned
work to shore up the cave's limestone ceiling and divert the natural water
flows. Two maps were produced by the sewer department, in 1904 and 1929,
showing a great deal of change in the cave's condition during that time.
The original NMT was designed
to funnel all of Minneapolis' waste directly into the Mississippi just
below the West Side milling district. In the 1930s there began to be greater
concern for public health and pollution, and the tunnel was extended south
and combined with other existing interceptors to form a tunnel leading
all the way to St. Paul. Pipes siphoned the flow beneath the river, and
the result of two cities' and numerous suburbs flushes eventually ended
up at the Pig's Eye treatment plant, still in use today. Under Minneapolis,
the NMT was diverted south at the intersection of 6th and Washington, and
a new tunnel was dug northwest up Washington Avenue from this point to
Hennepin avenue. This new tunnel served as a storm drain, carrying only
rainwater and occasional sewer overflows, and outfalling into the former
NMT discharge tunnel below the milling district. Branches reached up several
major streets downtown, sometimes following the sewer tunnels at a slightly
higher level, but only connected to the sewers at a few points.
Drain construction reportedly
revealed several other natural caves beneath downtown, but the location
and size of these cavities is quite vague, and any formal studies or exploration
remain lost in sewer department files. Various secondhand reports place
the next largest cavity somewhere to the southwest of Schiek's, and describe
it as being a 65ft by 22ft triangle. Evidence of cavities in the area can
be seen in one large and amorphously shaped drain chamber near this location,
which appears to be a natural void lined with spraycrete and incorporated
into the tunnel.
Exploring the systems.
The geological and cave resources of the Twin
Cities have been of interest to various groups off and on through recent
history. In the 1940s and 50s, a number of studies considered turning Schiek's
and other caves into bomb shelters, but concluded that artificial brewery
and mushroom caves were more suitable. Plans for a subway system in the
1980s produced a number of expertly researched but poorly depicted maps
of all known caves and tunnels beneath the cities. Developers have proposed
extending retail and commercial space downwards to maximize property use,
creating mined-space structures similar to Kansas City's limestone quarry
warehouses. So far the only practical application of these projects are
a few underground buildings on the University of Minnesota's campus. After
the brief 1970s oil crisis was over, energy-efficiency ceased being important
to city officials.
People have been illicitly exploring
the tunnels of major cities for as long as such tunnels existed, and Minneapolis
is probably no exception. Reports of unofficial visitors to the loop cave
date back to the 50s and 60s, and in the late 1970s a group of guerrilla
cavers made a late-night run to pop the hex lid and lower themselves into
the cave on a truck winch. In the late 90's, a website known as the Minneapolis
Drain Archive chronicled the adventures of a group dedicated to finding
their way into Schiek's cave from below. These explorers, led by Peter
Sand, discovered a number of interesting tunnels and features below Minneapolis.
They sailed up drains in canoes, swam into flooded tunnels, mapped out
the networks of tailraces and forgotten mill tunnels below the city, and
occasionally faced death or serious injury by drowning or high-velocity
liquid. Eventually they determined a route to Schiek's cave via the NMT
with the help of local caver Greg
Brick. Entering the interceptor sewer far upstream, Sand's group traveled
down to the cave access shaft and later emerged via the regulator at 6th
and Washington. This structure was referred to as the “Death Holes”due
to the frightening small apertures the sewage travels through before turning
south at the junction with the drains. Soon afterwards, Brick visited Schiek's
several times via breaks in the concrete tunnels, which offered a shorter
and less dangerous route until discovered and sealed by the city sewer
department. After the repairs were completed, it seemed that Schiek's cave
was again unaccessible to anyone unwilling to brave the full length of
the NMT or to face the wrath of police waiting at the top of a rope.
Another Visit
One day I found myself and a few other people
mysteriously transported by magical fairies to the heart of Schiek's Cave.
Well, the actual explanation is much more interesting than that, and in
fact much more interesting than the cave itself, but requires some secrecy.
Skipping directly to the cave found us in a series of low rooms and chambers.
We checked out a few famous sights like the NMT connection,
Little Minehaha Falls, the sewer to Schiek's nightclub
(not human sized), and the shaft to a hex lid set
in the street 75 feet above us. We contemplated exiting this way, but could
see cars running over the lid occasionally.
The general appearance of Schiek's is a low
(generally 5ft) wide space with muddy brown walls and floor, and a yellowish-brown
limestone ceiling. There are few if any natural features like stalactites
or soda straws, although the area around Little Minehaha Falls has some
interesting calcium deposits on the walls and floor.
Plastic straws, tampons, and other sewage-related artifacts
cover the floor near the strip club sewer connection. Cement pillars appear
frequently, installed to support the roof in case of collapse. Iron brackets
from previous surveys protrude from the ceiling in an effort to bash the
heads of explorers, and many other signs of human modification are everywhere.
The main passages form a series of loops, which have apparently been dug
out to enlarge the walking space, with some rubble dumped in other parts
of the cave making the ceiling clearance very low.
Earlier reports described the ceiling as being 8 or 10 feet high, so either
these were exaggerated or sediment and rubble from sewer floods has been
slowly filling the cave. Very low crawlways led off in several directionsbut
are mostly dead ends.
Seeing the way local city workers have pointlessly
destroyed other fine natural caves (such as Fountain's), I have little
faith in the future of Schieks. One of these days it will probably be pumped
full of concrete to balance a car park or use some surplus city budget.
When that day comes, or when circumstances change recarding the secretive
magical fairies, I'll post the full story and the rest of the photos here.
