Blackfoot news. (Blackfoot, Idaho) 1891-1902, 1899-06-17

HUM titue W tiIut pDIthDlc HPphI MUS
for determining gold In minerals, which
were supposed to enable the prospector
to decide whether the ore contained
any gold or not by the simple opera
ton OF dissolving the ore In acids and
adding stannous chloride to the solu
ton obtained II was assumed that
the formation OF purple OF Cassius
would give In all cases sufficient con-
firmation Of the presence OF gold.
Those who tried this process have
discovered. however, that the forma-
ton Of the purple could not be ascer-
tanned with satisfaction in solutions OF
gold ores containing but little OF the
precious metal, and have declared the
method to be unsatisfactory in such
cases.
At the present status of gold recoy-
cry, when ore containing So gold to the
ton is treated with profit. the knowl-
edge of reliable and simple method
for the determination OF the presence
OF gold Is OF vital Importance. The APP
paratus required, II at all acceptable TO
the prospector, should involve but lit
tie expense, occupy but little space and
do away with the application OF heat
as produced by spirit lamp, candle or
oil stove. In fact. any cumbersome
apparatus or complicated operation is
out Of the question for obvious rea-
sons.
The following methods, which allow
of the detection OF OOPS or. OF gold TO
the ton with certainty. offer all the adj
vantages pointed out above and leave
nothing toTbe desired as to practicable
ity or efficiency:
| ]. About OF. OF the finely pulyerized
ore is placed In bottle. an equal vol
nme of tincture of iodine is added and
| the mixture agitated.- The contents OF
the bottle are kept in contact for an
hour at most. With occasional agita-
ton. and finally allowed TO settle. A
strip OF Swedish filter paper is then
| introduced into the clear solution and
/ dried, these two operations being re-
peated six times, so as TO saturate the
paper thoroughly. The strip is then
4 burnt. when the ash. in case gold is
| present, will show a purple coloration,
which, on pouring bromine water over
II, Will quickly disappear-a sure in
dication OF the presence of gold. This
operation is best performed on plate.
2. The test for gold described above
may be altered In the following man
ner: About or. OF the finely divided
ore is covered with an equal volume OF
bromine water In the same manner as
above. After standing and agItaiine
for an hour, the solution is filtered and
tin chloride solution added TO the fill.
trate TO produce the purple of Cassius,
the appearance of which will indicate
the presence of gold.
The methods given are especial.
adapted for the separation of gold from
sulphides. 1t is necessary, however. in
this case 10 roast the sulphides before
the application of the process: an OPP
Grafton which can be readily accom-
plished In can or pan, over the camp
/ fire. When roasting pyrites for this
purpose the temperature toward the
end should be raised To a full red heat
SO as TO induce complete decomposition
and render the product porous and
readily permeahle for the iodine OF
hromine solutions. If the ores TO bt
treated contain an excess of carbonate
of lime, the roasted mineral should he
gently reignited with ammonium car
Donate, so as TO prevent the entry OF
much lime into the iodine or bromine
preparations.
To execute the tests described above
there would be required a few empty
bottles, n bottle of iodine tincture. an
other of bromine water, one containing
solution of stannous chloride. a cou
pie OF glass tunnels. some filter pa
per and some ammonium carbonate
surely list that cannot be surpassed
In simplicity, cheapness and adapted
ness.-Dr. ]. Ably. in Engineering ant
Mining Journal.