The Seattle post-intelligencer. [volume] (Seattle, Wash. Terr. [Wash.]) 1888-1914, 1896-10-13

81 The EngiehasdR b-omine gold exsracssoa
| process IL nov In opsratson X Ia fIA
90 orado. ana the fcsloxfng description ..
/ ~ Ores Ana .hesr treatment - condensed
from ne Enxfnesriny and Mining Jour-
uai:
ssTne pr4ncfpns ore bodies - fnr uncov-
ore0 occur n d.erste. ana Judging RON
the geosogscAi formation Of the La Flals
monnsaAns We believe that III the uanS
now msnerzsixsd with gcl3 VIII be confirm
Gus with increasing depth. The amount
OF sElvsr bssnx 80 ;sm.reA In most Of tho
Ores ne arc treating At the present nsn~
that ~ recovery can be omitted 10 another
posnf which We had fully considered when
seiectanx the shove process IA preference
- any other.
"Ax The beginning CT this seascn We
treated the mos. refractory ores from dif-
ferenk mines and had x1nl ~ opportunity %
confirm our calculation ~ 20 the size ana
value OF ore bottles ard. furthermore. our
belief that We had selected the mcst suit
able method OF treatment The works or
szfnally intended for the trea Of GUS
torn ores have FOR the last two months
been running Continuously on ore from
one Of our own mines. and we have GEM
onstrafe6 that the character Of the ore has
nat changed. The development work On
This property consists az . shaft u feet
deep with 40s feet Of drifts. At this depth
the gold and silver valsas correspond with
cAoss OF o,e ores mined close to the sur
face. We made exactly the same obscrva-
tons on al those veins OF the La PlatA
mountains where the nsrseral.zed eraptive
portions consist OF diorite. Sometimes tho
chemical analysis shows = slight variation
as 10 the percentage OF silica and iron
t7s tp IS per cent?. but the whole compost
ton OF the ore we arc treating now is
quite uniform. The analysis OF an aver
are sample. taken from 100 tons Of ore
gave the following results; Silica, Sos
per cent: iron sesqui-oxide. leo per cent;
ilme, loH pof cent: rnagnesia none: alum
Ina. 81 per cent: sulphur. $50 per cent:
totaa. ss.eS per cent The remainder OF lss
per cent. 10 covered by small quantities OF
copper. arsenic. chromium. t,tanfund snd
teanrHim. which are found and easily DE-
tected In solutions after treatment. The
vafnes IN silver ard gold Of different shin
= sn's were fonnd to be from LIS or to
OK IN gold and from a5 OF. to or IN
AVER Per ton As stated, 4 small nor
.soh OF the rod - found Il, be in n metal
nc state. though the largest portion "a
eomUned With telfurum and prohab,v -.
suipnlde Of gold In areenicl iron pyr,se.
ae any other chemical process This
oHe process requires careful a,ten-
ZION. ana the service OF n man ~h. %
familiar with the principles az che,,,..rv
snonsd De produced for its Management
WIN TINS knowledge and some exner,snea
IN milling no difficulty win be enca,ntersa
IN introducing nhis process with suocess
Athoush our roasting facilities are not
y. tne iasest pattern I've are using the
6rackHer fnruaee), we succeed In es.,;rs
. perfect dead roast IN eight non-. ,ns
Guiding time for charging and dl.chsrs,nr
me furnace. The roasted ore Is elevated
from the cooling door and cha rred into
= ieaa-uned revolving barrel, with water
eno tho necessary amount OF c.ham.cals
Ihe strength OF solution employed il on
"a s'ersse % per cent. but We found that
10 per cent solution. equal to az Mounds
OF oromins per ton Of ore. can \. ussd
70 aovantAge. The extraction Of the wo,a
axes Place In two 10 three hours. Gener-
aiiy one to enc and onA-haN hours Il sur
ncent tinc TO obtain . hish extrac.Ion
oH owing to the presence or free ro,d IN
caI ores we prefer to have the bromine
soptfons long enough IN centac. with this
more or less coarse gold. Ths leach,,y
rom the barrel takes place In thlrty-five
- torty-nve minutes. even on si,nav
cnargsa containing for instance. larre
quantities OF dus-duss. TIE solutions he
ing free OF slimes and perfectly clear 90
nor require any settling. We may state
mere tha: this Ii In our opinion q n imnort
ant advantage over the u,e OF barr,
chlcrfna;ion. where the shines OF sulpha,a
OF bme produced by chloride of lime ana
snlphuric acid require from twelve 10 TWEEN.
fy-iour nours settling. IL Is evident that
IN consequence much time can be saved
ana tbs capacity Of the works materially
increased
THE small amount Of brom,ne which
10 stsii present in the gold soiutsons-hirt
90 small that It's recovery can be a~psns-
cd willis easily eliminated by sulphorous
acid This gas is produced in a generator
by burning sulphur and introduced into
lie tanks with the aid OF compressed air.
which a the same time supports the burn
ING OF the sulphur. The gold (bromids OF
goid) Is then precsp.tatcd BY means OF suI-
paursstod hydrogen. a. xulphide OF gold.
This sas IL Introduced in the same manner
a. sasphurous acid. ac.ng produced In a
lsad-lined generator from iron matte ara
sGspharic ACID TIE elimination OF the
free oromine and precipitation o: the gold
taxes from asfsen TO twenty-five minutes
per eank holding !. .1e gallons ~ eold soI,-
ton. The precipstafes ars allowed to sat-
To In the tanks for about two 20 three
hours. and the supernatsnt n,ucr drawn
OF. running through = Johnston filter
presa The main bulk Of the gold precl,,-
ts,es Is left sccumuiatinx IN the bottom
or the tanks until q cleanup % made ana
chen run through the press. from which II
- taken 90 the rsrnlns process. This De-
'ng the sane operation a. ueed for the pro-
duct OF barrel chiorsaatson. It IL net neces-
sary 10 20 Into details. The average ex-
traction az gold on crss puiver;zea TO ls-
mesh varied from - to - per cent: In
was saved. all depending upon character
% ore and occurrence OF xoi3."
rWn FEET M s0Irn an