The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1916-03-09

reuse of the metals. The savings of
lead and zinc which would accrue from
the substitution of efficient for waste
full and slack mining methods are
many and large, but need not be par
ticularized here.
Conservation in Concentration.
Improvement in dry concentration
machines has made possible the ex-
ploitation of some lead and zinc dis
tricts which otherwise could have been
but partly developed, as for instance
the Yellow Pine district of Nevada.
Electrostatic and roast magnetic
separation have rendered available
large deposits Of complex sulphide
ores of lead, zinc and iron, such as
those in the upper Mississippi valley
region, at Leadyille and other dis
tricts in Colorado, at Park City, Utah,
and in the Cerbat region OF Arizona. 1t
has been recently discovered that zinc
blende Is rendered more responsive to
electrostatic separation by treating 1t
with a dilute solution of copper sui
phate which coats the blende with a
thin film of copper sulphide.
A newly invented wet magnetic
table process makes a successful sep
aration Of zinc sulphide from pyrite
and barite. This process has made
available the extensive zinc suphide
ore body at Edwards, N. Y, and should
find a field of usefulness in treating
the blende- barte deposits of central
Missouri, the blende fluorspar depos-
it's Of western Kentucky, and similar
ores elsewhere.
BY far the most promising field for
the conservation of lead and zinc by
more efficient concentration lies In the
more general adoption of ore flotation'
This process was tried unsuccessfully
at many places in the west several
years ago, but not until its successful
application to the zinc ores at Butte,
Mont, did it begin to receive practi-
cal consideration 1t made progress
rapidly, however, and is now being
used in treating zinc ores in Tonnes
see and Montana, lead ores in Mis-
souri, and mixed lead and zinc ores in
colorado Utah, Idaho and elsewhere.
In southeastern Missouri practically
the whole of the lead production of
approximately 100000 tons in 1915 was
made in concentration plants with flo
tation equipment. From the imper-
feet data at hand it is estimated that
about 1900 tons Of this output is an
addition due to flotation alone, and 1t
is calculated that the average mill re
covery is now nearly SIS per cent, COM
pared with n per cent before flotation
was adopted. In flotation, as in most
other forms of concentration, the rich
er the feed the higher the percentage
of recovery. In southeastern Missouri
the higher mill recovery under flota-
ton has permitted lower grade ore to
be treated, and thus the increase in
average mill recovery as given above
does not furnish true indication of
the advantage derived from using this
process.
AT Butte, Mont, the Butte & Su-
perior Copper company has been OPP
Grating concentrating plant at the
Black Rock zinc mine since 1910, and
flotation equipment was added in
1912. The mill recovery of zinc be-
fore the adoption of the flotation pro-
cess was 55 per cent but since flota-
ton was installed the mill recovery
has greatly increased, being S6.4 per
cent in 1913, 91,3 per cent in 1914, and
over 92.1 per cent in 1915. The re-
covery during the last quarter of 1918
is reported to be about 95 per cent.
The recoverable zinc content of the
concentrates produced in 1915 at this
plant was about $4,000 tons. At SIS
per cent recovery without flotation,
the yield would have been about A.
600 tons. This indicates clear gain
Of 10000 tons of recoverable zinc
year at single plant, A minor part
OF this gain. however, is doubtless due
to improved efficiency in other sec
tions of the MILL AS practically all
the $4,000 tons of zinc produced in
Montana in 1915 was concentrated in
mills with flotation equipment, the |
gain due to flotation in Montana may
be estimated at nearly 10000 tons of
zinc.
Ore flotation is extensively employ
ed in treating the lead and lead-zinc
ores of the Occur d'Alene district in
Idaho, j. M. Callow has stated that
the flotation process is used at the
Gold Hunter, Morning, Hercules, Bun
ker Hill & Sullivan, Caledonia, Last
Chance, Hecla and Standard mines,
employing so flotation cells and treat
ing daily from 1900 to 1000 tons of
fines and shines. Other processes are |.
in operation at the Interstate Gala i
han, Green Hill Cleveland and other /
mills in the district. Figures as to
tonnage treated and mill recovery are
not available, but as almost all the
zinc and 81 per cent of the lead output
of Idaho came from this district, the
gain due to flotation may be estim-
ated on the basis of the gains else
where on similar ores, at $4,000 tons
Of lead and 10000 tons of zinc. !
Ore flntation is amnloyad in the