The Anaconda standard. [volume] (Anaconda, Mont.) 1889-1970, 1897-12-09
GOLD DREDGING IN MONTANA
Eugene B. Braden Gives Interesting Account of Its
Progress in the State-FIoating and Traction Dredges

The following interesting article oil
gold dredging in Montana was writer
for the Engineering and Mining Jour
nal by Eugene B. Braden:
Coincident with Marshalls discovery
of gold in lS4S placer mining in the
United States bet an important IN
dustry and the pan. roeNcr. hunrcr
long tom. siuice and hydraulic followed
each other as succCssl>a improvements
The decentralization u ths SILVER mining
industry and the financial unrest Of the
present have directed the attention .
miner and investor faNai i the iar--
deposits of hitherto unavoidable placer.
The energy ana Thought that hav" been
given to this subject seem to have be-
come lately centure upon a drcdge Of
some description as adapted to present
requirements. In the light Of the fore
going conditions ! shall attempt to set
forth the results of such dredging eX
periments as have been accomplished
in the state of Montana at the present
thine.
1t is now generally recognized by
those engaged in such investigations
that placer mining embraces two dis
Hinct branches, one Of which is confined
10 the mining of gravel lying under
water. while the other applies to dry
or land mining. To meet the conditions
of the first a style of floating dredse
has been designed, and for the second
"a SO-Galfed traction ulGuSe mas Detn
brought forward. These machines diff
der widely in the style of construction,
but more particularly in the methods
employed for the excavation ana sub
sequent delivery of the gravel to
suice box. where the pulp is finally dis
posed of in both cases and the gold OBJ
dained. River dredges, or dredges con-
structed for working in water, are sue
reSSfully operating on Grasshopper
creek, in Beaverhead county. Traction
dredges or land mining machines are
working satisfactorily at Washington
Eulch, Deer Lodge county, and in Alder
gulch, near Virginia City.
The Floating Dredge.
In the first dredging operations under
water the raising of auriferous gravel
by suction was generally attempted
but without material success. This was
Followed by investigation into the dig
ging of gravel, which has resulted more
satisfactorily. Some three years ago
b dredge that had been designed by
III. ]. Reiling of Chicago. after the style
of those working in New Zealand. was
built by the Bucyrus company of South
milwaukee, Wis, and put to work on
Grasshopper creek. Operations for the
first season We're very unsatisfactory,
but with the knowledge that had been
gained this dredge was rebuilt. The
results of the second season We're more
encouraging, but the following winter
saw a second rebuilding Of the dredge
This has been followed by satisfactory
results. The suction dredge that had
been built in that place by the Chicago
Mining and Development company was
then remodeled by the Bucyrus COM
pany, which has installed two new
plants there during the past season.
The "A. T.. Gaeter' was launched for
the Bannack Dredging company last
June, and plant for the Bon Accord
Mines limited, is about completed. AS
this is the last boat built which has
been in operation a sketch of it follows:
1t is 102 feet in length. Sc feet wide and
draws about feet Of water. The
framework is of heavy timbers closely
braced and, together with the engines.
boilers and other machinery carried, the
total weight is nearly 100000 pounds.
Preparatory to the launching of such
dredge dam is built across the gulch
so that sufficient water is impounded
When operations commence the gravel
when washed is deposited behind the
dredge, which moves up the gulch into
the excavation thus made
Steam is generated by two tubular
steel boilers of the locomotive type, with
CRATES arranger to use pine and fir
wood for fuel. These boilers are of 125
horsepower capacity each Immediate
3y back of the boilers is placed a set of
engines which drive the buckets. raise
and lower the bucket-ladder or frame
and run guy lines which are attached
at the front of the dredge and anchor
ed outside, so that the dredge can be
swung in circle for digging purposes
on the .spud" at the rear end of the
boat, which acts as an anchored pivot.
This set of engines is under the control
of an engineer stationed in a pilot
house above the upper deck. From
Hhis post he has observation of all oio-
erations and handles the machinery ac-
cordingly by means of a set of levers !
connecting with the engines.
i Directly in front of and below the
engineer is the ladder on which an end
less chain of Sc buckets for digging is !
worked. These traverse this ladder. the
lower end of which is vertically adjust
"A BILE as to depth by means of suspen- /
sorry cables passed over a frame above I
and wound upon drum at the en-
CINE and under control Of the engineer I
5n the pilot house. This ladder is
swung at the upper end upon a perma-
nent 4 3-S inch horizontal shaft. and
permits the buckets TO exeaNate gravel
10 a depth of 30 feet This shaft is
driven by a sprocket and chain con-
nection with a ~ horsepower engine.
Between the bearings this shaft is IT.
sed with pulley having five faces ur
wearing plates to fit the links of the
chain carrying the buckets. Through
this the motive power Sc communicated
10 the chain and buckets for digging
in the gravel. This chain is swung
loose on the under side so that each
bucket has a horizontal drag of feet
through the gravel ana its loading ac-
"omplished as il passes over the pulley
above. The lower one. however Is
provided with six faces to fit the links.
and IS Hanged to prevent lateral mo-
zion or slipping off Of the chain while
working. The loaded buckets pass up
the laddef-way, which * fitted with
steel rollers al short Intervals for car
1ying the load. and ~-npty themselves