The Nespelem tribune. [volume] (Nespelem, Wash.) 1934-1936, 1935-01-23
Activities At Dam
Told By Writer
Cofferdams Will Be Completed
In April; Contractors Face
Difficult Job
BY MEL SON A. CHENEY

BY NELSON A. CHENEY
GRAND COULEE DAM SITE
December 20 saw the beginning of
the most difficult portion of the
work OF constructing the Grand
Coulee dam: the building of the
giant cofferdams which will provide
dry excavation space and divert the
water away from it's natural bed.
Sometime in April, the cofferdams
on each side of the river will be
completed, and two months later
concrete will start filling up the
forms, job which will last for the
remainder of the life of the pro-
ject.
| It is no easy task to prepare a
wall on each side of this great river
which will make possible the dig
ging out of all earth on top of the
granite bedrock. When all this ma
Jerial Is removed, the stream must
be diverted through one side Of the
cofferdam, while the bed of the
river is dredged to solid rock.
Use Steel Piling
Steel piling will be used to con-
struct the many -celled wall. The
first of this steel piling was driven
on January l, exactly on the prear-
ranged schedule of the MWAk. The.
first piling was driven at point
which will become one of the clos
ure" sections; that is, from these
sections, two on each side of the
river, will run additional walls
across the river, on each side Of the
axis Of the dam, in the shape of an
III" with double bar.
The west dam is much larger ana
| more complicated than the other
since it is through this side that tht
river will be diverted at a later date.
1t is approximately 600 feet long
over all. It starts at point inSho1e
from the normal water line, and
runs out at a tangent toward the
shore. A few feet past the edge Of
the river, it swings around. The
regulation sections are merely rec
tangular in shape, with rounded
corners, but the closure sections are
more detailed. They are shaped
somewhat like a four-leafed clover,
and are much larger.
Nonchalantly, over the rows of
wooden piling which will serve as
bases for working platforms, or
over the steel piling already in place,
clinging to the cable and hook on
the end of the "stiff -leg" booms, are
the men who place the piling. Seem
ingly reckless to watchers, they are
as surefooted as cats, knowing ex-
actly where the engineers OF the
machines will carry them.
Use Huge Machines
At present, there are three Of the
"stiff-leg" cranes at work at the
south (upstream) end of the Golfer
dam. These machines, with bOomS
as long as 100 feet, are mounted or
huge rock-filled cribs, about 20 feet
above the river, and can swing in q
27O- degree circle. They can be
used for either general derrick or
crane work, or for driving piliny.
Assisting them are two steam
powered "whirleys," which are
mere movable derricks, mounted on
wheels and turntable for working
at any possible angle. AS they
move, they pick up their track be-
hind them, and set it out in front
There are also a pair of shovels
converted into cranes by the substi
tuition of booms for shovel buckets
The whirleys are building trestles or
which the other equipment will
work.
The whirleys will later be sup
planted by electric ones, much larg-
er and capable Of handling much
more work. They are arriving, piece
by piece, now, and will be at work
before the month is up.
Work started January 4 on the
east shore conveyor belt, the same
day that dirt went over the rolls f
the permanent end units of the
west side conveyor. The latter
units are constructed of steel grid
erS in such a manner at to be made
longer or shorter as desired, and +.
dump at any point Of 180-hegree
arc. This movability prevents any
clcgging of the belt from the build
ing up of the dump below.
The east side belt will be only
four feet wide, instead of five, as .
| the west side line. There is less ex-
cavation on the east, and on the
| whole the conveyor will be simple
It must come up out of the excava-
ton pit, through a cut already made
for it, and stretch out over flat,
level plain several hundred yarcs
upstream. There is no canyon for
/ the dirt to empty into, and accord
ioU tn officials of the COMPANY It.