Lyon County times. [volume] (Silver City, Nev.) 1874-1907, 1893-12-09
THE CARSON RIVER DREDGE.

1SbtcIo vi fiiI oiAy SVACOA hih6 oAN
enterprise of the Carson River
Dredging Company, we have taken
pains to obtain definite and anthem
tic information regarding it, which
information we impart to our read
ers, even at the risk of republishing
some facts with which many OF
them are familiar.
The plan Of operation determined
upon last June, after the completion
and test Of the dredge, which proved
satisfactory in every respect, in
cluded the use of the large Bennett
Amalgamator. Those who were
acquainted with the work of this
and similar amalgamators believed
that under proper conditions this
machine would readily save GER
tain amount Of free, or amalgama-
BILE, metals, found in all these river
deposits, to the estimated value of
from one to two dollars for every
ton of material taken from the river.
The tailings of the amalgamator
were to be thoroughly screened, and
the finer sands submitted to the pro-
cess of concentration for the pur-
pose of saving the valuable sulphu-
rets. This process, contemplating
also certain supplementary appli-
ances, looked to the saving OF a
high percentage of values; and the
preparatory mechanical arrange
ments were all directed to this end.
Had the expectation regarding
the amalgamator been realized, the
output from this machine alone
would have afforded a fine profit,
as it was capable of treating the
sand of one thousand tons Il day of
average material; and, as this out
put could Immediately have been
turned into bullion, it would have
served the purposes of ready cash
in the development and completion
of the plant.
But by series of careful exper-
iments it was ascertained that the
amalgamator could not be made to
do the work which had been ex-
pected of it. Under the most fav-
orable mechanical conditions that
could be secured-those which
would have been sufficient for saw
ing all free fine gold in virgin placer
mines-it was found to be impossi-
BILE to retain the amalgam on the
plates after a small accumulation
had taken place. This was due to
the fact that most of the free metal
in the river is already in the condi-
ton of soft, semi-fuid amalgam,
and Toured quicksilver, lacking the
adhesiveness requisite to its reten-
ton on the plates under the attrition
of sand and water incident to the
treatment. The amalgamator was
therefore discarded, and the COM
pany was obliged to fall back upon
concentration, and certain auxiliary
appliances, for the saving OF the
precions metals.
This change was not considered
in the light of a misfortune, though
it deprived the company of the ben
eft of an immediate saving of the
free metals; for the use of the ANAL
gamator involved large expense and
not a little inconvenience, and the
conclusion was reached that the
ultimate recovery of values would
not be much increased thereby. 1t,
however, compelled futher delay and
necessitated the raising of money
for further work.
In September two Woodbury. con-
centrators were put in on trial, and
were found to work satisfactorily,
though the conditions under which
the trial was made were unfavora-
BILE to rapid and perfect work. A
homemade concentration has also
been tried, and the result exceeded
expectations. 1t can be used to
good advantage in connection with
the more costly machines, consid-
erably reducing the first expense of
complete plant.
The results of the test work done
by the two Woodbury. concentrators
showed that basis of large profit
can easily be reached. The work
work was done on the lowest grade
material (by necessity, low water
preventing change of location ex-
cept by continuous digging), and
the conditions were unfavorable to
high grade work. Nevertheless, on
the basis of the output in sulphu-
rets alone, only ten Woodbury. ma
chihes would be required to yield a
good profit. A value equal to that
of the sulphurets consisting in free
metal was lost because of the lack
of facilities which in a full plant
would be provided. This, too, was