Sierra County advocate. [volume] (Kingston, N.M.) 1884-1960, 1895-03-08
ORES OF IRON PYRITES.

y
or chlorination methods now in
use, have heretofore been found
for obtaining a fair percentage oil
the gold from auriferous sulphur.
cts OF iron (iron pyrites), aud
very few ores of this character
are of sufficiently high grade to
bear the smeiting charges even
when the mines are located near re-
duction works ana transportation
charges are light, while their sue
cessful chlorination depends upon
proper roasting-a condition
which Ia rarely attained, and only
at high cost, by the present meth
ods, and in some ores, at the ex
pense OF considerable loss by vol
atiIization.
Every practical mining man is
therefore painfully aware Of the
need of process that will treat
base metal sulphides chesply and
economically, one that can com
pate with the Gree milling" pro-
cess now in use, as to cost Of OPP
Grating, and that can save from
them a higher percentage of the
precious metals than is now done,
Whiie there hos been no lack OF
inventions claiming to accomplish
this object, (and in theory some
have good grousd for their claime)
in practice they have all failed, in
greater or less degree, to sub
stsntirte these claims.
Rich frds of free milling gold
or silver ores are now of exceeding
" rare occurrence. but ores con
taiaipg from $5 30 $50 per ton,
which cannot be prolitahly worked
by stamps and copper plates, are
found iu almost infinite number
aud variety; and it is for these
that We want designed a flexible
and comprehensive system of met
allurgy, by means of which the
correct theory of working any one
of them can be practically and
economically applied.
In all countries where operations
for the extraction OF gold quartz
VEINS have been carried OF. the OK.
idized or free milling ores, So
called, are generally comprised in
that portion of a mineral vein
which lies above the water level
proper. They are IN that portion
of the vein from which the refrac-
tory Clements have been oxidlzed,
leached ouC, or eliminated by in
fuences which have been acting
through centuries.
Below the water level these
gold bearing VEINS generally as
sumo the form of gold carried in
sulphurets or other combinations,
IN which form they are but in q
slight degree amalgamable.
1t is known that rusty" gold
ia the result of the decomposition
of aurlferous sulpburets Of iron,
and that most of the gold found Is
or has heen associated with base
metal sulphides. The oxidation
of the pyrItes by slow, natural
processes sometimes leaves the
particles Of gold in amalgsmable
form, but often a coating of iron
oxide is thereby formed upon them,
aud this latter condition obtains
10 high degree when sulphurets
are ariifieiaIly roas'ed by any Of
the present methods; and az this
rusty" gold will not readily unite
with mercury it is not susceptible.
to copper plate amaigamation'
therefore pans are commonly used
on these ores, in which The ore
mercury aud chemicals are ground
together; bat though pans are
more efficient on these ores than
stamps and plates the grinding III
them tends to produce float" gold
aud hoored mercury, and the
method is slow and costly. snd the
rDsuIting bnllion Of low grade.
The most effective method nov
ia -Rss ~Ee.s.saFas3sDg gold ORES, III
part free milling aud in part pyrlt-
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