Bisbee daily review., 1917-12-02

count, written by Courtenay DE kalb
is taken from the current issue of the
Mining and Scientific Press:
Large-scale teaching tests have beer
conducted for a period of nearly eight
months at the Copper Queen mines al
Bisbee, Arizona, following work fol
three years in precipitating copper
with scrap-iron, in preparation fol
handling the disseminated sulphide
ore recently developed in. Sacramento
hill The orebody, as tested by drill
ing, and further confirmed by under
ground exploration. has shown a large
tonnage, some of, which is of grade
suitable for smelling without previous
concentration. The larger volume
however, with tenor averaging about
1hGs copper, VIII be treated by flo
tation. In addition, large tonnages
that assay no higher than 0.9 to 1c,
copper will be available. This lower
grade ore will be .leached and it is
proposed to treat it in heaps, taking
advantage of the reactions that occur
through oxidation when the mass is
treated with the requisite amount OF
water. The principle, of course. is the
same as that long utilized at the Rio
Tinto mines in Spain, but the details
whereby the system is made adapta'
BILE to American conditions have been
evolved by Joseph Irving, who is in
charge of the operations at Bisbee
The novel features introduced into
the process are found chiefly in the
precipitation, which will be consid-
cred first AS now conducted, taking
into account the existing costs of sup
plies and labor. the entire process
has demonstrated recovery of soc,
of the copper in the ore, at a cost OF
zoe. per ton for transporting the ore
from the mine to the backyard, build
ing 0e the heap, and disposing of the
taiiings; zoe. for teaching; and Sec
for precipitation, including cost of iron
consumed, charging current rates for
the scrap-metal. The ore treated in
the experimental heaps has AVERAGED
1856 copper, yielding 20 pounds ce
ment-ccpper per ton of ore. The ce4
ment is obtained as an unusually high
grade product, assaying 608c copper
The cost of the whole operation, there
fore. is only sc. per pound of copper
recovered. To obtain the total cost
OF the copper there must be added
the cost of mining, shipping of the ce'
ment-ccpper TO the refinery, melting
polling and casting.
II will be seen that the precipita-
ton is the most expensive step in the
process. When applied on a larger
scale this cost will be reduced, OF
course. and improvements are even
now being made that will effect fur
Their economy. At the present time an
average of about 100000 gallons OF
solution is passed through the preci
pitation watts daily. Only 10000 gal
Ions OF this comes from the leach
yard; the remaining 100000 gallons
consists of water from the Gar shaft
which contains about 69 grains of cop
per per gallon. The experiments in
precipitation we're conducted on the
mine-water for a period of nearly three
years before "heapleaching" was tried
The possibility of economically reduc
ing the ferric 10 ferrous salts by the
use Of Mr.. lrving's pyrite filter was
thus proved. and this paved the way
for successfully treating the lowgrade
sulphides developed by drilling the dis
seminated granite porphyry ore on Sac
ramento mill. AS a preliminary to the
precipitation of the copper from the
mine-water it is essential to eliminate
the solids carried in suspension. The
larger portion of the solid matter is
removed by diverting the water
.bro,,,b shvp+ 70 pl,c ,.-bara tho oh
ing Of the current causes it to settle
Most OF what remains is then caught
in the pyTite filter.
The arrangement of the shunt-tank
is illustrated in the accompanying
sketch Gig. u. where F. is the flume
carrying the mine-water. the diver
sion-laUnder with a gate G, which may
he changed so as to close either the
flume F, or the diversion-launder S
T is the tank, 80 feet long, feet wide
and 6 feet deep. The tank is provided
with discharge-door. D. near the bot
tom, for flushing out the accumulated
sediment About 400 cubic feet OF
sludge is settled from the mine-water
in three months. and it assays from
O.3 to 1eS copper
Filtration and Reduction. After the
coarser material has been settled the
waters are conducted to the filtration
watts at the head OF the precipitating
plant As originally designed it was
intended to use six watts, in each oil
which would be placed approximately
80 to As tons OF pyrite ore to serve as
a filter The watts are round and are
made of Gin. redwood. As now con
structed, the solutions are caused tC
flow downward through vertical box
pipes at the side and then TO pass up
ward through the filter-bed. discharg
ing At the opposite edge OF the vat in
to a ? r. by 10-in daunder The filter
is composed OF pyritic ore, from y tC
/ in. diameter. with some fine mate
rial. assaying about 2rc copper. The
bed Is 21s to IT. deep. and is sup
ported upon a wooden grating resting
en- by Gin beams The solution
flows through each filtration vat al
the rate Of 100 gallons per minute. and
the filter retains 7514 of the solid mat
ter still an suspension. In addition, the
pyrite converts the ferric salts in the