River Falls journal. [volume] (River Falls, Pierce County, Wis.) 1872-2019, 1904-02-18
RIVER MUD HOLDS GOLD.
DredEes Used in California Streams
TO Drag Rich Minerals from
Their Beds.

/
Not all the gold OF the Pacific coast is
| found in mines. The waters of the bays
and rivers yield the precious metal in
| plentiful quantities, and dredging in
| these waters has of late become profit
| able industry. Such an enterprise is be-
| ing carried on in the Feather river
meadows, below the city of Oroville, in
| Butte county, Cal. 1t consists in re-
moving thousands of tons of gold-bear-
| ing mud and gravel from the bottom of
| Feather river, which in some places is
more than 20 feet in depth, says San
Francisco paper.
From Is to 20 great dredges are en-
| ployed in the Oroville district, each hav-
| ing a capacity of from 1000 to 5000 Gu
bic yards every "a hours Some OF the
great floating mines burrow down into
| the river bottom as far as IS feet so feet
| from the surface being the lowest depth
at which the big shovels operate.
For many years mining men in that
district in California, which was made
famous in the days of 40, have been try
| ing to devise scheme to get hold of the
gold which lay far beneath the surface
of the rivers. In 1898 Capt. Couch put
upon the Feather river the Pioneer, the
first dredger constructed after $50 900
had been expended in experiment. AT
the present time there are 81 dredgers in
the gold streams of California, each es-
pecially constructed to suit the locality
in which it is to be worked.
| The success of the dredgers has been
| phenomenal Last year the floating
mines produced almost 81 100000. This
| year the miners expect to double that
record The ground worked averages
about Is to rs cents and often more per
cubic yard, but the cost of operating the
dredgers, including an allowance for
wear and tear on machinery, is in many
of the dredgers only four cents per cubic
yard, and in none of them does it exceed
| Y cents.
1t is only from % to so feet to bedrock,
and as this is a sedimentary deposit Of
many years it is easily eXcavated. The
dredgers at work at the present time are
| taking out 25, 900 to 1000 cubic yards of
gravel daily 1t is strange sight to see
| these great dredgers nosing along the
river like some huge amphibian mon
sters, while often the river banks are
| bordered by orange orchards or waving
grain fields. A great deal of the low land
| bordering on Feather river has been
| purchased by miners, and the dredgerS
| rapidly eat the land away until the wa
| ters rushing in reduce it to a soft and
| easily worked mass.
Two classes of dredgings are used.
/ The more popular form consists OF an
| endless chain of buckets. These lift the
auriferous gravel on an inclined plane
! to the head of the sluices and concentrate
ing tables attached to the dredger The
machinery which operates the bucket
belt also pumps the water used in the
| concentration in separating the precious
| contents from the dross.
The principle in extracting the gold
flakes and minute nuggets is Identical
with that adopted by the old placer miner
| in the days of 40, when he washed the
gold in his cradle in some of the very
| localities where the dredgers are now
| operating.
The only type of dredgers is the scoop
| dredger, in which great shovel is di-
rected beneath the surface of the water
by a huge beam, which moves UP and
| down upon rotating axis. This shovel
works in much the same way that an or
binary shovel does in human hands.
! When the shovel is filled with gravel
| from beneath the river bed the bottom
of the scoop opens and the gold-bearing
detritus falls upon the concentration. At
tempts have been made to work" these
river beds with suction dredges, but
these have not been successful as the
| high specific gravity of the gold enables
| it to escape from the suction when the
cutter breaks down the pay dirt.
Placer-dredging is yielding excellent
profits One outfit with twoN dredges
averaged net profit of~S600 day for
three weeks. 1t is estimated that there
is now invested in California almost
SO 900, 900 in this branch of mining.
Cup OF Coffee $4,000.
A naval officer who has just returned