Fergus County argus. [volume] (Lewistown, Mont.) 1886-1946, 1904-06-29
Mining in Fergus County.

year 1903. The Kendall Gold Mining
company and Barnes.King group, al
Kendall. and the Gold Reef Mining
company. at Gilt Edge. all continued
to produce during the year as prev
iously and have a visible supply OF
ore for a long time to come. An In
teresting feature at the last named
property Is the great body OF unox'
idized ore which after roasting is
amenable to the cyanide process. FOL
the following report which bears on
this. | am Indebted to the superin'
tendent of the property, Mr.. j. h.
Mccormick:
The property of the cold Reef Min
ing company is located on the east
slope of the Judith mountains, Warm
Springs mining district, about one
mile west of the town of Gilt Edge,
Montana, and consists of twenty-sev'
en- patented claims. The present com
pany came into possession OF the
property in October, 1902, by pur-
chase from the Great Northern Min
ing & Development company, who car
ried on the most extensive operation
in its history and built the present
cyanide plant.
The country in the vicinity is a
carboniferous limestone and the ore
body occurs at the lower contact OF
an intrusive sheet of porphyry and
the limestone, the general strike be-
ing north and south, and the dip 30
degrees northeast, the dip being in
conformity with that of the underly-
ing carboniferous limestone. At the
Storm King claim the everything por-
phyry is entirely eroded away so that
the ore has been mined by open cut
ting. Up to date the values have
been obtained principally from the
oxidized ore and in the upper and
older workings from the auriferous
porphyry. The oxidized limestone is
a typical cyaniding ore containing no
base metals or rebellious constitu-
ents. Silver and mercury are pres
ent, but not in sufficient quantities
to be determined by ordinary meth
DDS. The gold cannot he concentrate
ed by any known method and no mat
ter how high the grade, it will not
pan a color.
The present ore body of unoxidized
black ore underlies the previously
mined oxidized ore. The oxidized ore
requires a solution of less than n
per cent in cyanide and the consump-
ton of cyanide per ton of ore treated
is about .25 pounds.
The black ore will not yield up its
values directly to cyanide, but re-
uuires roasting. Personally | conduct
ed a series of tests on several hun
dred tons at the property during the
fall of 1902.
An experimental plant, consisting
of a hand rubble hearth furnace 5 X
20 feet was constructed and a leach
ing plant of three five-ton tanks six
feet eight inches deep 1.-THE same
depth as the tanks at the MILD, also
the necessary solution tanks and the
zinc boxes.
A number of preliminary tests
were made which demonstrated that
equally good results were obtained by
roasting the ore crushed to one-quar-
ter-inch mesh as when crushed inner,
so the most of the charges were
made of that mesh, and as that Is
the mesh used in crushing he oxidiz-
ed ore it was a favorable feature,
since it would allow using the same
crushing and screening plant through.
out for both oxidized and unoxidized
ore and as above mentioned the OK
idized ore overlies the black ore, they
can be mined at the same time and
sent to the mill separately and crush
ed ready for treatment much cheaper
than il separate sizing was neces-
sary. 49,
The oxidized ores are given a fair
rate of teaching, then roasted a very
high one as the two will be mixed In
going to the teaching plants, the mix
ture will give a very satisfactory rate
for teaching. 49,,
The ore does not require a high
heat and the ideal roast is obtained
by keeping it at an incipient red heat
for about two and one-half hours in
the presence of abundance of air,
which means frequent and thorough
agitating. The raw ore carries on an
average IL per cent sulphur and az
ter roasting rs per cent of which
.634 per cent is water soluble.
The ore can be roasted at from 500
to 900 degrees +. in a prolonged per-
iod. but more practical results are
obtained at from 1000 to 1900 de-
grees F.. the maximum being 1,4OO
degrees. at which time the lime in the
ore is changed to quick lime, which
Is prohibitive on accoun OF TIE Slack
ing and packing of the charge, inter-
fering with the teaching. VI.
The average weight of the ore at
a quarter mesh charged into the
tanks is oxidized ore IS lbs, black
ore 81 lbs. per cubic root.
The main ore body is reached by
a mill tunnel which nearly parallels
the ore above, being about 100 feet
lower at the mouth and intersectlng
II at its northern end. Ore Is run
TO the tunnel level by chutes or at
the north end by two gravity IN
clines. Ore has been found and is
being developed near the north END
by a 1876 foot Wine which appears 10
show q fault OF the ore body.
The Standby workings are about
1,SOO feet west of the mill tunnel and
are $50 feet higher, ore being run
by a line chute to a tunnel 1900 feet
long which branches from the mill
tunnel 600 feet from its mouth.
The surface plant in addition to
the 800 ton cyanide plant and the
Brown Straight Line Rooster (which
is now in operation), consists Of a
ten drill Rand Compressor. a large
Corliss engine and a battery of -four
boilers. An ample water supply is
now obtained by a 3 mile wooden pipe
line s inches in diameter from Whis
ky gulch.
An innovation in prospecting In this
district has been introduced In a dia
mond drill lately installed.
The Chicago-Montana Mining com