The Black Hills union. [volume] (Rapid City, Pennington County, Dakota [S.D.]) 1889-1904, 1895-10-18

den playing OUT of the ores in the
mine Que to more or less geological pea
cullarities for which our Creator alone
is rG@ponsible.-Mining Industry.
COLONIZATION OF GOLD ORES.
Sketch OF the Development of This Pro-
cess.
The extraction of gold from it's ores
by the use of chlorine was one OF the
greatest advances in the metallurgy of
this metal ever made. The first prac-
teal method for applying chlorination
was the Plattner process. and the first
place where it was applied in this
country on any considerable scale was
i'll Grass Valley, California, by the late
G. II. Deetken. The Plattner chlorina-
ton consists in putting the iine. roasted
ores in g wooden tank or lead-lined
wooden tank, to q depth OF several feet.
closing the tank aud allowing the chic
rims gas to penetrate the mass from the
bottom. Yle supply Of chlorine is
kept on for two or three days until the
whole mass Of moist ore has been thor
o1ghly chIorinated, when the gold, CON
verified into chlorine, is IeacheG out with
water. This; process involves the grind
lug and roasting Of the orc, and usually
it's concentration. and it requires fouI.
or five days FOR the charging, chlorina-
ton. washing and discharging OF the
charge. The charges amount to from
tive to twenty tons. rarely moro. and il
consequently requires a great many
tanks. The solution is drawn into set
ting tanks. and finally into p%recipitat-
lns tanks. where the gold is p%recipitat-
ed by ferrous %sIlphate and the clear
solution decanted OFF so that the whole
process requires n very extensive array
OF lead-lined tanks.
The next step in progress was to
shorten the time required for chlorina-
ton by the use OF the revolving, lead
lned barrel. These barrels were made
1T first to hold IL ton, then three tons,
row five and ten tons. They are cllarg-
Ell very quickly. The chlorine is GEN
Grated in The barrel by the use of cal
ciilm chloride and sulphuric acid. When
~ehloflnated the charge is, as formerly.
jumped on sand filters and washed,
out his washing was an extremely
tedlous operation, especially when the
sand litter became clogged with the
calcium sIlphate and fine iron oxide
from the charge. Various devices were
adopted, some with q great measure Of
success, to shorten the time of washing
on the litter, II to effect 4 more per-
fecS washing of tho charge. Even with
these it required a great number Of
filter tanks.
The next step was to wash in The
barrel. This was done first at Deloro.
Ontario. the Wasll-water being elnptied
out OF the ch%iorinating barrel with only
avery little of the charge mixed with it.
50 thai the most Of the charge remain
ed in the barrel until thoroughly wash
eu. when it YVES carried away By 4
stream of water to the waste pump.
The small amount that went out. with
the solution went into Il settling tank
ana then the solution went through fl
fers. This greatly lessened the use OF
hlters, but it required q good deal Of
time to wash the charge. Efforts were
then made at continuous washing Ey
pumping water through one trlilnion
and allowing it to flow out through the
g~oose-nock which connected with the
ether trunnion. but this was slov. on ac-
count OF the necessarily small size ec
the pipes that passed through the trllns.
lions.
Ilc next step was to dump the entire
enarge into q separate filter vessel and
% wash under pressure, but this has al
% some difficulties. among which may
mentioned the Irregular washing Of
eRe charge. The water will find free
passages and will follow them and not
mass through the remainder of the
charge. There are also other difficult
ties which it is; not necessary to men
ton now.
Mr.. John e. RothweI suggested, and
has since carried out practically on q
very large scale. the washing and fill
tering in the cl~llorinating barrel itself
and has found this a rapid and excel
lent method of doing the work. In
tlSs first experiments he used an asbes-
tos filter, but it was difficult to get SER
viccable asbestos cloth, the life of the
cloth being short and the cost high.
Mr.. RotllWell then built barrels with 81
sand filter in them and by the use of
pressure he is enabled to wash the
charge very rapidly. thoroughly and
economically Engineering and Mining
Journal.
The following dividends have been
l ,,psf7 J,x,AA II o., -, - - = 4 .Hx.. L,rAs 49,