The Anaconda standard., 1898-01-10
Instructive and Interesting Pa
pers Read at the Banquet.
THE MISSOURI RIVER DAM
About Its Retiring Presi-
dent Goodaie's Address a Resume
of Work Performed and
Under Way.

unanimous NerdlCt that the banquet
was one of the most successful and
thoroughly enjoyable affairs of the kind
ever held in Butte There were nearly
100 guests. The menu was excellent and
well served, the wine plenty. the music
excellent and the toasts bright and
witty.
A paper of general interest read at
the meeting of the engineers was the
one by T. NJ. Ripley, engineer in charge
of the Missouri river dam. 1t was as
follows:
The practicability Of damming the
Missouri river near Helena for power
purposes has been considered more or
less favorably by engineers and busi-
ness men of that city for number OF
years. In fact, one party made prellm-
mary surveys at a point on the river
about six miles below the site of the
present work, but never got beyond the
preliminary stage. Moreover, the gov
ernment made an examination OF the
Missouri from Three Forks to Canyon
Ferry in 1892 and 1888 under the direc-
tion of Captain II. F. Hodges. and sur
veys and maps We're made by Il. l..
Vincent, assistant engineer, of five dam
sites between the two places mentioned,
the fifth one being at Black Rock Cam
yon, at the site of the present work.
THE maps above mentioned have
been of great value in prosecuting the
present work and tracing. The project
of the present work was promoted by
II. L. Cooper, who Interested Thomas
A NARROW and Samuel t.. Hauser in
the enterprise and through their influ-
ence together withathat of Barton Sew
ell Of Chicago the funds were obtained
for prosecuting the work and the COM
pany incorporated under the name of
the Helena Water and Electric Power
Company. Cooper was put in charge of
the work at it's commencement in July,
1885, and his resignation was accepted
March /, 1897 when w. p. Matthews Of
St. Paul was placed in charge of con-
stFuction All work has been done by
day labor, the only contracts let being
for machinery and material not procur-
able on the site.
Before the beginning of the work j.
T. Tanning of Minneapolis was retained
as consulting engineer and all plans fer
the dam, power house ana hydraullc
machinery have been made in his office.
Moreover the work has had his person
al supervision from time to time during
it's progress. The construction of the
dam is a timber crib filled with rock
with three aprons TO break the fall Of
the water and thereby reduce the scour
below the dam. The timber in cribs is
fastened together with 20 and 30-inch
drift bolts, and the end cribs rest
against pilasters In the abutments
which rise To a height of 12h feet above
the crest of the dam. The abutments
being built on the edge of the original
shore line the spillway or crest Is prae-
tieally the same length as the width of
the river at the site The aprons are
built of two courses of l0xl2 timbers
laid on the Pinch side, thus giving a
total thickness of 20 inches of solid TIM
ber. The risers are covered with two
thicknesses of three-inch plank lap
jointed and the back with two-inch
plank similarly laid, against which a
dirt fill is placed and rip-rapped below
drift.
Below the dam fer distance Of .
feet the river was filed with large rock
to the surface Of the water, the rock
being held in place by close row OF
round piles. The distance from plank
facing on back of dam TO said row Of
round piles is approximately IS feet.
The crest is % feet above mean low
water and length of same is 4So feet.
The cribbng rests on the bed OF the
river, which is a compact material COM
posed of gravel and granite sand and
practically impervious to water. Golfer
dams with the sheet piling forming
same being driven to depths of only
four and five feet had their enclosed
spaces exceptionally free from water
when working under head Of 10 feet
with the material eXcaVated as close 10
the piling as its natural slope would al
low without undermining the sheet
piles. Both above and below the crib
sheet piling built of 3x12-inch pine
plank stiffiy bolted together, driven 10 a
depth of l. feet below the bed of the
river or. when the material was too
hard. until the pile was in danger OF
splitting or would go no further under
the blows of a 2.250-p0und hammer fall-
ing on to an 1,l00-pound cast follower
placed on the head of the pile. All ma
sonry where possible had a similar row
of sheet piling driven around its foun.
dation as an extra precaution against {
current forming under the structure.
The flood line will extend up the val
ley a distance of about six miles ane
the lake thus formed viii cover an ap
pIoximate area of FIVE square miles. Thi
above area contained about 500 acres
of hay land besides unreelaimed islands
government, school and Northern Pacific
lands. The majority of the ranch prop
erty, which included the above men
toned 1000 acres, had TO be secured
through the courts as the company wal
able to settle with only two out of j
individual owners Government inves
legations at the site placed the flow o
the river at mean low water at $50
cubic feet per second. This amount
with a 29-foot fall. gives 5.S9i.25e foo
pounds per second or los.o hors
power.
ION the east bank of the river a fl
+ with a slope of y by ! on the dow
stream and to / on the up stream sid
was built with masonry case 10 IN
height of the abutment and extendei
back to the corresponding contour q
the hillside. This fill Is practically a
extension of the dam proper but ne
designed as weir. Adding the lengt
S.0f said fill 2s5 feet TO In
- length, ass feet. gives a To
agth from west abutment 10 cas-
170 feet. The west abutment resi-
native rock and the clin ras
NIhis point at an angle ~ Al dc
Out OF this cliff abOur !" 600 ca
ards of rock were taken 10 max
forebay and excavation for the pen
ks From the back of the abutmen
extending across the cxcayatio
mentioned is a heavy masonry wa
sich holds the penstock heads. Til
snstocks, five in number, extend fror
mis- wall 10 the power house 75 fee
II north. The penstocks were built on th
j