The Goldfield news and weekly tribune. [volume] (Goldfield, Nev.) 1911-1947, 1916-10-07
NEVADA DOUGLAS
PLANT ENLARGED
MORE EQUIPMENT PROVIDED TO
BRING ABOUT HIGHER
METAL RECOVERY

With the installation of additional
tanks for the handling of the oxi-
died ores, the teaching plant of the
Nevada-Douglas Copper company of
Ludwig, Nevada, will be completed
and in a position to handle 500
tons of ore a day, according to Su-
pe~rintendent Archie j. Orem. The
experimental work has all been
completed and working operations
have been thoroughly tested out, so
that costs and all the metallurgical
problems have been solved.
The work at the plant has &C
complished three things, the low
ering of the cost of power, the max
ing of the plant as near automatic
as possible, and the doing away with
making sulphuric acid with which
to do the teaching. Relative to the
latter it has been found that one
ton of Is per cen sulphur ore con
tains fumes sufficient to leach one
ton of sulphides and four tons of
oxides. The sulphide end of the
plant has been finished and the
tanks for the oxidized ores are
now being put in.
The fumes are created in a muf-
fled Wedge furnace and the present
plant has a capacity of creating 49,
600 cubic feet of gas a minute. This
is run through four tanks for the
sulphide ore and six tanks for the
oxidiZed ores. The sulphur tanks
have a hopper bottom and are fed
by a screw at the top. The feed is
mixed with an equal amount of wa
ter and is so arranged that if so
gallons of feed a minute are put in
circulation, the pumps from the bot
tom of the tank remove the solutions
to the top of the tank again at the
rate of 1000 gallons a minute.
The tank is filled with Stats to
delay the fall so that the solution
comes in contact with the fumes 20
times a minute. 1t has been found
that 40 minutes is all hat is nee
essary to leach the finely ground
calcines, although with the fouI
tanks that the solution is run
through, it car be extended to so
minutes.
At the bottom of each tank is a
suction pump for conveying the So
lutions from the bottom to the top.
At the top is a feed adjustment that
carries part of the feed to the next
tank. The feed of the gas is SO
adjusted that it permeates the en-
trio fnnk with an nXha1Cf in the
last tank.
The oXidized ore tanks receive
the gases from below while in the
top of the tank there is a spray OF
water and solution that falls over
the ore as the gases go through it,
In this part Of the plant there are
t. be a sG'.e. o. six tanks. El"l
tank has i ~capacity of $50 tons or
ar3roximately =AA0 tons for his
sections. The solutions after be; :"
drained through a sand filter in
the bottom, are again returned in
the spray until the copper liquor is
nf the required grade.
An experimental plant has shown
that SO per cen of the values car
be saved with ore ground to n and
a half inch mesh. 1t has been
shown by the experiments that have
been carried or that the total treat
ment cost of oxidized ores of a fou,
per cent copper grade is $1.46h a
ton. This also includes the precipi-
tation. which costs IL cents a
pound, and 26k cents a ton for
crushing and teaching. 1t also
shows that 1S days of contact witt
the fumes in teaching the oxides is
necessary. The tanks are also inter
changeable.
Although a large amount of eX-
perimental work has been necessary
on the mill, Mr.. Orem believes that
this stage is 10Y passed.
From the mine a car of 12R
per cen copper ore is being shipped
each day and at the same time two
tons of second-grade ore averaging
AZ per cent is being taken out anc
stored for each ton of h~igh-grade
mined. The mine is in shape sc
that this production can be main,
tanned for some time to ONE
unuNNVVNLND CNDE NOD