Daily camera., 1897-02-16
MINING METHODS.
a New Way of: Extracting Gold
from Quartz.
Chemical Processes by Which Every
Particle of the Precious Metal
Is Saved - Recent Expert
ments.

There are two general methods of sep
arating gold from The rock with which
it is associated IN a vein. In beth the
ore is crushed TO d ceI,atr degree of
hneness, greater or less, according to
circumstances. The stuff is then
washed with water over ia layer of mer-
curry, with which tt gold amalgamates,
or else (perhaps after! preliminary
roasting) mixed win a!chemical soIu-
ton which diss-,lvns t.heLrrecious metal
Subsequently, the gold il covered from
the aMaIgam 'or the solui IN by further
treatment. In the sy&tCIi ia which
quicksilver is employed there is always
a certain loss of the precious metal.
lnasmuch as the rock is exceedingly
hard, usually quartz, it is subjected to
heavy hammering in the final stage
of pulverization, and in consequence
some OF the particles of gold are fiat
tened into tiny plates or saucers, and
toat away with the wash water Then.
too, the mechanical separation is not
quite perfect, and a little of the gold
still remains imbedded in the minute
bits of rock which go off as refuse, or
''tailings" As il is usan. = rather high
grade ore which is handled in this way,
the loss is apt 10 be disregarded. But
there has been a great tendency to-
wards more. economical methods of
late years. and some of the chemical
processes now III vogue are well adapted
TO the treatment both of ''tailings'' and
lOw-grade ores.
Attention has recently been directed,
in England and Australia, to still an
other plan of insuring the recovery of
i very large percentage of the gold
originally existing in the ore The main
idea involved, that of breaking up the
quartz by alternately heating and cool
ing it, is Old; but some of the details
of tht process are new, and tits claimed
for the so-called "ore-atomic" system
that it is more successful than any pre-
vious attempt in the same direction.
In the preliminary crushing the rock
is brought down only to small Jumps
of convenient size, and not to actual
powder. The material is then incIosed |
in chamber from which the outside |
air is carefully excluded, and the cham
ber is. placed ina furnace, in which, |
beside the fuel, there are pieces of red
hot iron. a jet of steam is thrown upon |
both the coal Tor coke) and iron, and |
the result is the development of water
gas and hydrogen. These gases have
access to the chamber, and prevent the .
oxidation of the metal. Indeed, j f. there
be any oxide in the ore it is reduced
by the hydrogen. Any sulphur which
may be present is also eliminated, pass
ing off in the form of sulphuretted hy-
lrogen. After the ore has remained
in the heated chamber for a time whose
length varies. according to the cOmpo-
sition of the rock, it is suddenly
''quenched" by the injection of cold
water Inasmuch as the fragments to
which this first chill breaks up the
luartz are not as small as could be
desired, the water is drained off and
he series of operations is repeated sew
eral times. Finally the contents of the
,hamber are dumped into a tank. When
Sooi
.ween the fingers, it crumbles into pow
Ter easily. No heavy stamps are re-
luircd to pulverize the substance now.
t is alleged that there is absolutely no
oss in the form of float gold" and no
oxidation, and therefore that all the
precious metal originally in the ore
nay be recovered.
In some experiments recently made
With the ore-atomic system in London,
samples of Cripple Creek and West Aus
ralian ores We're treated. An English
weekly publication, Invention, declares
hat disinterested experts were pres
mt and assisted in the tests. 1t adds:
In every respect the results were most
and unquestionably dem
,nstrated the correctness of the prin-
iple involved" 1t is announced that
he West Australian Gold District cor
,oration has bought the right to use
he ore-atomic system.-N. Y. Tribune.
SPEAKING TO THE DEAF.