Sierra County advocate. [volume] (Kingston, N.M.) 1884-1960, 1895-08-30


the form Of scales. Second, the
atoms of gold are so small IN many
cases that il Is not practical TO pull
veiize material hne enough to free
them, and should they be freed in
many cases the atoms are SO small
they would float in the water. In
this way atoms Of gold are lost.
after beng freed Ivy pulverization
rs well as those hte ms that are
floattd tnd lost Iii mechanical c, m
binaiion with particles Of gangue.
where they have not been freed by
fine lulHerzation.
Sulphureis usually contaia the
values in gold and silver ores, and
If high percentage OF the sulphur
cts are saved by mechanical con-
centration, it Is All that can oe
expected But mechanical concen-
tration falls far short OF this, there.
fore the vast expenditure that has
been made for the purpose ot
performing impossibilities. A fiat
particle OF ore may be lost, while a
cubical particle of rock may be
saved Of the same solid contents.
the specific gravity of the ore being
several times greater than that OF
the rock. For an illustration, i
will take n fiat particle of ham
mered gold one -huudredlh part Of
an inch square and one-thousand
eth part of an inch thick, and the
probabilities are . that such
shaped particle of gold will float in
water, The water being in motion,
which it has To he or it would not
bring about u separation. In any :
case, if we make the particle one
tenth of an inch square and one
thousandeth OF au inch thick it
will yet float, having The same solid
contents that cubieal particle OF
gangne has, the sides of which are
ont- -Aundredeth part Of an inch the
gold being five OF six times heavier
than the rock. Still, the rock
sinks IN water and is saved by
concentration, while the gold IL
lost and passes off with the tall-
ings, and can only be recovered by
a chemical process. So that IN any
case of concentration happy
medium shonld be sought-that
is, save portion OF the gangue
and lose a portion of the ore, in
such proportions as will make the
greatest profit.
1t is my opinion that where the
values are contained in the sui
phurets and free gold contained
them, that If a good system OF
concentration Is used amalgama'
tion in connection with concentra-
ton is worse than useless, besides
adding greatly to the expense. The
gold that is saved by amalgama-
ton would be saved by concentra-
ton il it was left in the ore, and
the smelters would give little
better rates on rich ore than on
low grade ore. Not only that, but
tho fine pulverization that is used
for amalgamation causes a greater
loss in the shines than is gained
by amalgamation, even if amalga-
nation should save small guam
tity that might be lost in concen-
tration. Ore can be concentrated
for 81 per ton where the facilities
are good covering wear OF machin-
erv and interest on cost of same.
/ will state another point on
concentration h is better TO lose
some Of the value by not crushing
fine enough, than to crush too tne
and lose ihe value in the shines.
And still another point where the
happy medium sh0ala Se seana -
besides coarse crushing is cheaper.
Rools are The best for preparing
the ore for concentration, and
when the ore has passed through
them it should be screened through
such sized screen as it is deter-
mined to reduce the fineness Ut the
ore to, and the coarse to be re-
turned automatically until it all
passes the desired mesh screen. In
the above manner ore is sllmed
less than in any other way. A
rock breaker of some kind is usu-
ally used in connection with roofs.
Yours truly,
Wsr TR-pwewn-
y -afh