The Butte inter mountain. [volume] (Butte, Mont.) 1901-1912, 1901-10-05
THE BOAT IDEA SUGGESTED BY
CHICAGO CANAL WORK,
VALUABLE COIN SCOOPED UP
A Cache Encountered on the Site of
Henry Plummer's Cabin-Ten One
Dollar Coins and Nine $3.50
Pieces Brought Up.

railroad car, between men who never
saw a placer mine i'll operation, that
Bannack and Beaverhead counties owe
the installation of dredse boats in the
| placer beds of this county. says the
/ Dillon Examiner. One of these men was
| interested in the company which now
! owns the Greater and Graves boats in
! Bannack. and on his return to Chicago.
he took the matter up with his friend.
| At that time the Chicago drainage canal
was being dug and the suggestion was
made that the dredge system which was
| so successfully in use in that work.
| could be likewise employed in the hand
| ling of the placer beds of Grasshoppe1
| creek.
| The proposition met with favor and
| an examination of the Rannack diggings
| was made. with the result that the pro-
| ject was deemed feasible and an option
was at once secured on q considerab bic
portion on the placer ground at and
near Bannack That gold existed in
paying quantities on bed rock was a
self-evident fact. for, upon every bar
mined in early days good pay was
found. In nearly every place the rim
rock was also worked and a great deal
of drifting was done as we'll. The bed
rock in the creek bed was too deep to be
worked by the old-tine sluce box or
ground sluicing methods and the best
of the gold was still on the bedrock be
meath 50 feet 70 gravel.
The Electric dredge or the F. L.
Graves. as it is named. was the first
boat ever built in the United States TO
be used for gold dredging purposes. Its
machinery was ordered in 1894, from the
Bucyrus company. of South Minneap-
oils, and the boat was launched in the
spring of 1895. Three weeks later its
machinery was in position and it be
gan work. Power was supplied from an
electric plant which is situated at the
lower part of Bannack, at which point
the boat was launched. In order that
the boat could be fioated dam was
built which raised the water about six
feet. Into this reservoir the boat was
launched and at once began digging it's
way to bedrock. The electric plant gen.
crates 100-horse power. and with thu.
water power available. fall of 367 feet
1s0-horse power can be generated. The
water is secured from a ditch which.
with all its branches. is 60 miles long
and the services of two men are re-
quired throughout the season to patrol
it and keep it in repair.
AT first the electric boat was fail
ure. 1t did not use the elevator buckets,
but the gravel was pumped up by sue.
ton. This system brought all of the
lightest materials to the surface, but
the heavier ones, including the gold
We're left snugly resting on the bedrock
One season was all this system was tried
and afterwards the elevator buckets
were substituted for the suction pump
Dol,
as master mechanic. and. under his Ii
rections, the boat was built in 1898, with
the elevator double-lift system in use.
From the time it was started, after re-
modelling, to the present time. its pay
roll has been continuous. Never at any
time has there been a permanent shut
down during the placer season.
The boat has a capacity of 1000 yards
of gravel per day. and it will on an aver
age dig 1900 yards of gravel daily
throughout the working season. It re-
qulres three men-a motorman, pilot and
deck hand-on each shift to operate the
boat. The bucket chain is equipped with
36 buckets, each having capacity OF
five cubic feet. The ladder upon which
they work is so arranged that three of
the buckets are always digging N
gravel, and the speed of digging is gem
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is dumped into rotary hopper which
screens out all of the coarsest gravel
and it then passes off into the pond at
the side of the boat. Everything that
will not pass through a screen 4x5 inches
in dimension is dumped into a submerged
hopper, from which it is pumped by p
inch centrifugal pump into the sluice
boxes, where the gravel is washed over
rifles similar to the means used in the
early days. The dump is at the rear Of
the boat and the platform upon which
the sluice boxes are supported rests on
scOws. A big rubber pipe. called rub
Der neck" joins the sluice boxes with
the boat. The water for washing the
gravel is pumped up with the grave
through the 12-inch pump into the sluice
boxes. The sluice boxes are made 81
pressed steel. The buckets are Of press I'd
steel with movable lip. which can be
replaced upon it's wearing out. Each
bucket and link weighs 1000 pounds, and
| the safe-breaking strain of the link is
| 100000 pounds.
AS a general rule the electric dredge
digs six months each season, and since
| it was launched it has worked a mile II
the creek bed. which has averaged sc
feet to bedrock. 1t is estimated that in
going this distance $500, 900 cubic yards
of gravel have been moved, or an aver
age Of 100000 yards each season. The
| boat has still three seasons work in
sight. and after that is worked it will
probably be dismantled and moved 70
some other placer field in the county.
On the A. F. Greater similar means
are used in handling the gravel, and the
boat has the same capacity as the other
| On account of steam being used as the
motive power. the season averages one
month and half longer than the other
| boat. Two 1O0-horse-power boilers fur
nish the power. 1t was first launched at
Marysville. little hamlet less than two
miles below Rannack, and 1t is now dig
ging in the lower part Of the old capital
During the time it has worked it has av-
eraged $4,000 yards Of gravel each
season. The boat has just completed dig
cling over an old tailings dump which
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