San Andreas independent., 1857-10-31
On the Use of Mercury in Gold Mining

Better forever to hold to the right!
On the Use of Mercury in Gold Mining.
Translated for the aAlta California" from conmuni
cation in the Echo du Pacifque," signed "B. Defs
NUMBERI. I.
1t is impossible to form a satisfactory idea
of the immense amount of gold lost in all mi
ming processes, in spite of all the precautions
and care taken to save it. The precautions
are almost innumerable. To the capital of
ideas already acquired every miner adds daily
the little sum of his knowledge, and the fruit
of his researches and experience. For if the
California miner is the most hospitable being
on the face of the globe, he is also the most
ingenious, at least in practical matters. In
deed his position requires him to be So
Treadng continually upon buried treasure,
often spurred by want, always excited by the
golden fever, he is occupied, day and night,
in studying and dreaming upon the most CT
fective means of increasing his chances of
success Therefore it is that the inventive
spirit of this zouave (of new species) knows
no other limits than those of the impossible.
| wish | could represent all the various
methods of employing mercury in mining so
as to be visible at one view but the subject
will not permit it. | shall, therefore, confine
myself to the method which / employ; and in
principle it includes all the other methods.
1t is necessary, in the beginning, to remark
that mercury does not attract gold as the mag
net does iron, but merely attaches itself to
the more precious metal when the two come
in contact 1t follows from this principle that
all gold mining, wherein mercury is used is
defective, if its purpose and result be not to
throw the two metals into contact. This brings
me naturally to the system used by myself,
The principal use of mercury is in sluice
mining. The sluice is a long trough, or series
of troughs, through which a stream of water
runs, washing the auriferous earth thrown in
with shovel. The clay, mould, and other
soluble matter are taken up by the water; !;
the gravel and stones are carried down by a
swift current, and the miners task is to keep
the gold from going with them. The sluice
or trough has a fat bottom, usually from
twelve to sixteen inches wide. About twenty
feet from the head of the suice, and thence
downwards, / nail on the bottom little wooden
strips or elects, an inch high and ten inches
long, so that they reach from one side about
two thirds across the sluice, their direction
being oblquely down stream, forming angles
of 1909 and 600, above and below, with the
side which they touch These elects are fixed
alternately first upon one side and then on
the other; the lower point of one being oppo-
site to the beginning of another. The whole
forms a zig-zag course through the lower part
of the sluice.
Gold weighs nineteen times more than wa
ter bulk for bulk, and therefore the particles
move slowly in the sluices, and usually on the
bottom, so that in my sluice they follow the
zig-zag course of the elects, while the dirt and
much of the gravel flies over them. At the
head of the sluice | have quicksilver in a little
vessel with hole in it, so that the liquid
metal escapes continually, drop by drop, into
the trough below. The merccry having spe-
ciic gravity fourteen times greater than that
of water. cannot jump over the elects, but
must follow their zigzag, coming directly into
the path of the gold. almost every particle of
which must be overtaken by the more rapidly
moving globules of the quicksilver and thus
amalgamation takes place, in many cases,
between the two metals before reaching the
reservoirs for mercury in the lower sluice
boxes, to which many miners entrust the entire
business of catching the gold.
Without pretending to criticise systems
which differ from mime, shall remark that
ono common error in the making of sluices
seems to be in the multitude of rifles (cleets
nailed at right angles across the sluice-box)
serving to imprisou the mercury, which is
thus deprived of its best means of action !:
.manyof the particles of gold being carried
over it by the current of the water.
The usual method of separating the mercury
from the gold, is to press the amalgam in a.
niece of linen cloth doubled, whereby most of
the quicksilver. which has entered into the
amalgam, escapes. The mass remaining in
tie cloth is put in a frying-pan and heated,
and the mercury passes off in vapor. A little
mercury is lost in this way, but the loss is SO
small asspot to be cared for now. but the time
win llscomc* when the miners will be moro eco-