The hydraulic press., 1859-06-25
MINING WITH QUICKSILVER.

1t has always been desideratum with our
miners who employ quicksilver in their op-
erations, to contrive some plan by which
continuous surface Of the amalgamator could
be presented, and over which all the dirt
washed would surely pass and come in con-
tact. By the old processes this was not ac-
complished. The subtle metal would retire
to crevices, lay against rifles or in water
worn hollows, and thus eiude contact with
the finer particles of gold; amalgamating
with such particles only as found it by their
own gravity and would, perhaps, have been
saved without its aid. Hence, the object
sought to be accomplished by the use of
quicksilver was not attained, and the great
waste of the precious metal only slightly, if
at all decreased. Even in this vicinity, where
mining is more Systematically and intelli-
gently pursued than at any other locality of
equal extent within our knowledge, there
has ever been large loss of gold, in spite of
hundreds of feet of sluice boxes and the use
of enormous quantities ofquicksilver. Some
claims extend sluices for ten or twelve hun
dred feet, and have in these as much as three
or four hundred pounds Of quicksilver, which
loses at the rate of about seventy-fve pounds
amonth. Beyond these main siuices others are
laid for much greater distance, for the pur-
pose Of catching and re-washing the earth
asst goes down to the river. The sluices of one
company On San Juan Hill reach the enor-
nous length Of nearly,or quite, six thousand
feet. Yet beyond all these, the washed dirt
is found to contain gold, and men are pre-
parng to work the river bed to obtain it,
Some of our miners believe they lose fully
one-fourth, if not one-half, of all the gold
their claims contain. 1t is now known that
much of it is in the form of an impalpable
powder, which is visible only when gathered
in quantities. Doubtless the most of this
auriferous dust, literally speaking has not
heretofore been saved. Suspended in the
dissolved earth, without sufficient gravity to
precipitate and come in saving contact with
the quicksilver, it fioated away and was lost
There is reason now to hope that some of
the loss described above may hereafter be
prevented, and the productyness of our deep
diggings much increased. Some weeks ago
we described the valuable invention of Mr..
S. Briggs, of Michigan Bluff, Placer county,
whereby wooden blocks, such as miners Law
in the bottoms of their sluices, are charged
with quicksilver and made to present con-
tinuous surface Of that metal, sufficiently
thick 10 amalgamate readily and retard the
gold. This valuable invention may be brief
ly described as round iron cup, OF bowl,
made of any desired size, the sharp rim of
which is struck into the block. The quick
silver is then placed within it and by means
of lever and valves atmospheric pressure
is brought to bear upon the metal until it is
forced into the pores of the wood the re-
quired depth-say two, four or six inches,
the block being completely silyered About
three of these blocks are placed in the sluice
at intervals of twelve or fifteen feet, aud the
friction of dirt and water wears them suffi-
ciently to keep always exposed a surface of
quicksilver. As the gold catches on this it
is urged along more slowly, until it is partly
amalgamated and drops into the creEices be-
tween the blocks, CT at their sides. Within
the last week these charged blocks have been
introduced into the San Juan diggings by
Messrs. Moore 4 Readshaw, who have very
high opinion of them, and expect to save by
their use both gold and quicksilver. Mr..
Readshaw has purchased from the patentee
the right to the invention on this hill, and,
we believe, is ready to charge blocks to or
der, at reasonable price. If the quicksi1-
vered blocks accomplish all that is predicted
and expected of them, they will not only
enrich their originator but save to the mi
ming community of our State many millions
Of money.