The Indianapolis journal., 1902-01-19

pvV'vvv. II taps the chicago river some 0lS-
tance above it's mouth and causes its foul
waters. mixed with large quantity drawn
from the lake, 10 flow a short distance up
stream and then through the canal into the
Desplaines river, and thence TO the Gulf of
Mexico. The canal is cut 10 a depth OF
twenty-three feet below the water level
and for several miles through the prairie
Is nearly 800 feet wide on top, and required
the excavation Of over 2S0,OO0.OO0 cubic yards
OF earth which had TO be dug up, lifted
out and piled in great hills. often hundreds
Of feet away from the edge of the canal
bank.
CUTTING ILLINOIS RAVINE.
As the average price paid for excavating,
lifting and removing the earth was about
one cent a cubic foot, only a fraction of
what is usually paid for ordinary guam
titles of excavation, the contractors were
obliged TO invent cheap methods and the
great principle of success was found 10 be
in handling the earth in large quantities
and keeping it continuously moving. Most
Of il was dug by steam shovels working
in the bottom of the trench, which could
scoop up a wagon load at once; and do
it on an average of once minute or oft
ener all day long. In one place the steam
shovel worked back and forth across the
canal cutting a section ten feet wide and
fourteen feet deep a each trip. Each buck
etful of ton or more of hard, sticky clay
was dumped by the shovel into the hop
per of a grinding machine, which delivered
il on top of an endless winding rubber
belt extended across the bottom of the
canal. a second belt reached up TO the
top of the slope and in turn overlapped
the end of a third which was carried along
the floor of 2O0-fOot bridge elevated thirty
feet above the ground on rolling towers
at each end. Each of the three belts was
supported on rollers followed little in
the center, like dice boxes, which made it
sufficiently cOncave to retain the clay, like
a trough. They were driven al a speed of
about seven feet per second, and cease
lessly carried the clay away from the
shovel up the canal slope, on top of the
bridge and over it TO a variable point,
where a diagonal scraper was set across it,
and pushed the load off, to fall through the
bridge floor and pile up on the ground un-
derneath. When the steam shovel COM
pleted a cut across the canal, which per-
haps required two days, it's tracks, the
belts and the bridge were all moved ten
feet ahead and the process was kept up
continuously. Many of the chunks of clay
were as large as mans head, and it was
amusing to watch them ride quietly along
until they commenced the ascent of the
steep bank, and then begin to roll and
tumble ,and start down with an evident
I determination not to go up that slope un-
der any circumstances They would hurry
and scramble as fast as possible, but it
was not steep enough for them to fall
quite as fast the belt Travelled, and it
would keep picking them up again and
again, each time lifting them a little high
er before they would succeed in starting
down, until at last they were landed on
the level belt on top.
Blasting a tunnel through the solid rock
is usually considered an easy and a com
paratively safe task; excavating ii in solid
clay with a good depth of the same ma
terial overhead is sometimes still easier.
Even quicksand may be pierced at the ex-
pense of sufficient time and money, but
when t is necessary to tunnel through soft
mud and slit very near the river bottom
i'm deep water the task is one of the most
difficult, dangerous and costly that can be
attempted. Such a tunnel with an inside
7 diameter Of ten feet was recently built in a
very novel manner. A huge concrete tube,
/ 225 feet long, lined inside and covered out
side with steel plates. was built on shore
/ on regular inclined ways The ends being
/ closed, the 1,OOO-ton mass was launched like
a ship, towed thirty miles TO place, sunk
/ between rows of guide piles driven on both
sides of it, and one end connected by divers
/ to the shore tunnel previously built to join
it. The most remarkable feature of the
I work cfO 4
/ ened to injure the floating tunnel before it
was quite completed. Large valves were
/ hastily opened and it was allowed to fill
and sink to depth below the storm action.
| When it was calm again the water was
/ pumped out and the great pipe rose to the
/ surface, was completed and again sunk.
/ this time permanently seating itself on the
/ foundation piles cut of accurately by sub
merged steam saws at the required level.
far below the surface of the river.
! In sinking deep shafts through quicksand
it is often impossible to keep out the water
so men can work in the bottom. The sides
will cave in continuously. quicksand will
enter like water through the smallest crew
/ ice in the lining and tons of it will flow
/ from a long distance underground SO as to
/ cause depressions in the surface at remote
1 places. W OTSJ OF All, the SanQ ana water
/ will rise up in the bottom as fast as ii can
be pumped out. and this, added to the great
| pressure on the sides and the difficulty of
\ building a water-tght lining from the top
/ down, makes the work extremely slow and
/ difficult Recently the expedient of freezing
+ the quicksand far below the surface was
adopted. and after that was accomplished
the shaft could be excavated easily.
FREEZING QUICKSAND.
The freezing is accomplished by the use
Of the modern refrigerating machine. A
shaft about fifteen feet square and 100 feet
deep was sunk in this manner through
water and quicksand to solid rock at Iron
Mountain. Mich. few years ago. Twenty
seven ten-inch iron pipes were arranged
about three feet apart on the sides OF
rectangle iuclosing the shaft and sunk ver-
tically to rock by water jet and steam
hammer. An eight-inch pipe, closed at the
bottom. was lowered inside each ten-inch
pipe and the latter withdrawn. A one and
a half-inch pipe, open at the bottom. was
lowered inside each eight-inch pipe, reach
ing nearly to it's bottom and extending
through it's cap top. The tops of the
inner pipes were connected to a pressure
pipe. through which brine from the re-