The Eureka sentinel. [volume] (Eureka, Nev.) 1902-current, 1920-05-08


many other mining districts has large
ate ores carrying varying amounts OF
silver and gold, that would be profit
able to work If some method OF ex-
tracing their metal contents could be
devised that would not neccessitate
smelling. There are hundreds Of
thousands OF tons of carbonate ore in
this district assaying from 10 to ~
dollars per ton, that to mine and
smelt on the ground leaves little or
no margin of profit. There is a large
tonnage of higher grade ore that
would yield much more proit than
Il now does IL q successful treatment
by leaching, concentration or volatili-
ration methods, or a combination of
these methods could be perfected.
Not only would a large profit be rea-
lized, with the reflection OF more ex-
tensive mine operations from these
profits, but the costs OF reducing the
ores mined of the district would
be expended here, and a marked in
crease In the general business OF the
camp result therefrom.
The discovery of successful
application or some Of the methods
now under investigation to eureka
ores is therefore OF great Importance
to the district. That some method
OF treating the low grade, oxidized,
lead ores, will soon be worked out Is
assured, and while every district has
certain local ore characteristics, re-
curing modification of ore treatment
methods successfully applied TO SINH
lar ore in some other district, a cap
able metallurgist will be able to plan
q method applicable to each produc-
ing mine. Not all ores. by any means.
are to be included as material sus-
ceptible to new metallurgical pro-
eesses, but the less complex ones OF
the Eureka district are especially ia
vorable for rehabilitation treatment.
Concentration of oxidized lead ores
always results in a large loss OF val
ues, and a good recovery would be 90
per cent OF the lead. silver, and gold
contents. 1t is apparent that con-
centration OF lead carbonate ores will
prove profitable only in exceptional
cases.
Flotation methods of concentra-
ton. however. are being developed
on some classes of oxidized ore with
marked success. AS fiotation depends
upon the floating OF particles OF sui
pnide ore when coated with q film of
OIL. 1t becomes necessary to artinciai-
ly surface the oxide ore particles
with a film or sulphide at the COM
mencement OF operations, following
this sulphidizing by regular notation
methods.
Many patents have been taken out
FOR the suiphidizing OF oxide miner
ais. Some of them propose the use
Oh gases. such as hydrogen sulpnide
and sulphur dioxide. These gases
are applied to the ore while IL is in a
dry state. the sulphur reacting with
the metals in the oxides to form
him OF sulphide. Other patents
are for the use OF solutions or water
and sodium or calcium suipnIdes,
the crushed ore being in contact with
the solution for a number OF hours.
In all cases. the sulphidizing is fol-
lowed by fotation treatment for the
separation OF gangue and mineral.
Probably the most successful In
stance OF profitable Notation OF lead
carbonate ores Is the method used by |
the Shattuck-Arizona Copper Com
pany at Bisbee, Arizona. At this
mine there are large bodies of lead
carbonate ore that are not associ- |
sled with the copper ores. In the
company's Investigations OF methods |
70 save the values of these lead ores |
Dy concentration, 1t was found that |
the ground ore when immersed in a |
solution OF sodium sulphide for a |
period OF about two hours was sui |
pnidized completely, and saving OF |
more than 80 per cent of the lead and |
snVer values could be made by fiota- |
uon. The strength of the solution |
used was from five to forty pounds |
ol sodium sulphide per ton of ore.
me tests proved so promising that a |
large mill for treating the lead ores
mas been erected, and the results OBJ |
Mned In its operation will be OF
great value to all interested in min |
'ns oxidized lead-silver ore.
The Shattuck ore contains a small |
percentage of iron. Ores with large |
percentages of iron, alumina, and
manganese, in various forms, have |
MOI yet been successfully treated by |
'nls method.
vast amount of experimenting |
sas peen done in testing different |
aeories of teaching lead and silver
1aes from ores by the use of brine.
ss,uined with sulphuric or hydro
.aioric acids; and also by roasting |
uo chioridizing the ore with salt or
"Me other chloridizing agent. and
Sacning the resulting material. The
sic theory of this treatment Is,
~. py converting the lead and silver
su'ents OF the ore into lead and sill
l enlorides, which are soluble in
lne solutions. the metals can be !
Sssspitated and collected from the
,su sauons. Good recovery of the lead ,
% -, oe made by these methods. but
v part OF the silver is saved.
s',sssnins processes offer a promising !,
~ ior some classes of ore. and are |
S,..s S,s thoroughly tested by several
-'a'ns companies.