The Idaho Republican. [volume] (Blackfoot, Idaho) 1904-1932, 1923-01-04

west. A year or TWO ago some
workmen found within the cliff!
under Shoshone falls one of the big
gest mortar pestals of the world.
A mortar postal is a stone bow
and the accompanying rock fol
doing to grain what a grist mil
does. 1t was the primitive grist mill
of all people, and at the time of the
coming of the white man in America
it was still doing duty among the
Indians. The river course where il
crosses a bed of lava, hollows out a
good many of them, and does it by
rolling cobblestones around in any
hollow in the rock where the cur
rent furnishes the power to keep the
rock rolling in circular motion
long enough to wear it into the per-
feet form for milling. Some of
these bowls are not larger than a
hens egg, and some of them are
large enough for hens nests or
larger. The one in the cliffs under
Shoshone Falls was fifty feet in
diameter, and was discovered in a
peculiar way.
During the hot months of the ir-
rigating season, very little if any of
the flow of Snake river is allowed to
pass the Millner dam, and then it is
only by accident. If water is being
released from Jackson Lake $50
miles up stream, sufficient for all
the needs of irrigatOrs and there
happens to come rain or cool wave
to stop irrigation or make less
evaporation in the river, then there
may be surplus of water for a day
or two that gets over the dam and
is lost.
1t was during such period that
the Idaho Power company was
developing it's generating plant at
Shoshone Falls to utilize the spring
water coming into the channel be-
tween the Millner dam and the falls,
and they sought to turn all of the
stream thru the penstOck. In order
to do this they had to build a wing
dam across the channels forming
the north wing of the cataract. At
one place a great crevice drew a tor
rent down thru the cliff and let it
out on the face of the cliff in a good
many places. In order to stop this
leak they had to build a cofferdam
fifty feet high to hold the water
away from that part of the channel,
and even then it leaked some. The |
structure was about eighty feet |
long, and was made of 5000 sacks of |
sand, thirty-one willow mats six feet |
square and a fot thick, thirty-one |
wagon loads of straw and 1851
cubic yards of earth.
When they stopped the flow as
oh
loot wall of water eighty feet wide
little upstream from the
crevice they wanted to close and
seal, the pressure of the water on
The dam was 5000 pounds per
square foot at the deepest and every
yimlet hole spirited it's stream of
water 1t was grave question
whether the dam would hold for
my length of time, and even at best
t leaked enough to keep workmen
rom doing anything at cleaning out
md sealing the crevice unless a
Jump was operated to take care of
he leakage.
The engineer in charge of con-
truction had anticipated all this
nd had an eight-inch centrifugal
Jump installed and by keeping it
umming they could keep the Gre (.
ice in condition for work. If the !,
saks increased in volume, some .
hing else would have to be done to
latch it. A trestle had been built +,
nd concrete mixer installed with
mall cars to rush materials out to
for filling the crevice when 1t was
sady for filling.
Explorations in the depths of the t
revice revealed an oval bowl fifty t
,et in its greatest diameter, worn n
Y gravel rushing around under t
alter pressure, and by the side of b
another hole like we'll, three o
,pth. They cleaned it out for ten c
et down and then decided to fill q
lie side Sits of the big bowl with I
'ncrete in sacks and build on top r
the mass of matter that lay in the p
,ttoms of both the bow and the Il
ell. This was at a point sixty feet Is
Glow the surface, and it was diff II
cult to get up and down because lc
e crevice was irregular and a man d.
uld not climb the slick sides as 81
, does in well, because it was of p
lch varying sizes. If the Golfer
m should break while a man was fC
the crevice, no human aid could re
ach him, and the dam would be d,
rely to break if water spilled over b.
g Miner dam twenty-eight miles ra
stream. til
The situation was getting critical; pt
ards watched every change of m
lor in the water as it came from m
e leaks, and the pump was kept at si
full capacity heaving water out pl
the basin sixty feet below the id
rface. Somebody had to go down dr.
% the depths to place the sacks of ST
ncrete as they were lowered, and M
would have to work fast and re
ig, when once it was started, of
yer quitting the job till it was M
ished liz
Jack Hurley was the foreman in lei
arge of construction and he was I'M
ted for always protecting his men
any cost. They would go to any in
It he sent them, and feel assured a
It he had made every provision los
their safety, but here was a thu
ce he would send no man while the
present strain was on the Golfer sta