Elk City mining news. (Elk City, Idaho) 1903-1913, 1905-06-17

plant would be a 1OO-ton plant. Ii the
plant discharged tank only every other
day, it would be only 5O-ton mill.
Teaching tanks, as well as all other
tanks used around the plant should set
up off the ground so that every part OF
them can be readily examines for leaks.
If properly set up on substantial foun-
dations it is not likely that any leaks
will occur; but it is best to be on the
safe side and not take any chances. 1t
is a good idea to give the tanks couple
of coats of P. & B., or If this is not
done, to soak them for few days with
strong alkaline solution, preferably
one containing caustic soda.
A filter bottom is of very simple con-
struction. A grating is laid and either
nailed or screwed to the bottom OF the
tank to prevent it from floating. On
top of. this is laid either burlap or cocoa
mating, and canvas on top of this.
The under filter is put in simply as
support. To hold the canvas down on
the sides rope is driven down on top
of it between the sides of the tank and
the outer ring which encircles the graf
ing.
If the ore is to be sluiced out, one or
more discharge gates are put in. Be-
meath the filter is placed the various
pipes with the necessary connections for
either admitting or drawing off the
solution.
The gold tanks are placed below the
teaching tanks so that the solution can
run into them by gravity. Sometimes
for want of elevation they are dispensed
with, but this will necessitate increas-
ing the size of the sumps. Whenever
possible they should be installed. These
tanks need not be very large. The
height is usually or feet. Two tanks
are always used-one for weak and one
for strong solution. These and all other
tanks should be constructed with vertis
cal sides. They make a stronger and
tighter tank than those constructed with
batter, and are much easier to set up.
This is an important point in their favor,
for in the remote mining districts to
which these are shipped skilled labor is
usually scarce and costly.
Insome plants where the rate of perco-
lation is very slow, montejus or vacuum
tanks are used. These are large steel,
air-tight drums connected by pipes to
the bottom of the teaching tanks. A
pump exhausts the air in the vacuum
tank and the extra pressure created on
the solution in the teaching tank brings
on a more rapid percolation. Their ac-
ton is intermittent. AS soon as the
vacuum tank is filled it must be emptied,
and then the pump has to be started
up again and the operation repeated
Guages are attached to show the pres
sure within, and the amount of solution
The capacity of montejus varies from
two to four tons of solution. They are
not often used, but when they are in
stalled are of great assistance. They
are placed above the gold tanks. By
using two montejus in series the perco
lation may be made continuously, one
montejus being emptied while the othe.
r is filling.
Below the gold tank comes the pre-
, cipitating department. A great man.
different opinions exist regarding tn
construction of the precipitating boxes
/ The ordinary type is long, narrow boz
, divided into a series of compartment
and with battle boards arranged to fore
the solution up through the zinc shaw
7 ings. The dimensions of the compart
: ments vary. The general opinion
} that they should be narrow and dee
rather than broad and shallow. Mos
7 cyanide operators prefer to have tn
5 solution flow up through the zinc rattle
2 than down. The former arrangement
D causes a maximum precipitation at tn
4 bottom of the compartment which tend
2 to stop up the space under the scree
: with the precipitate and short Zinc
2 With down flow this is not so apt
= occur. Another point in favor of tn
q down flow is that there is less tendenc
f for the zinc to rise when there is an e1
h cessive evolution of gas or during whs
is known as foaming, when the solutio
e becomes excessively alkaline. With
: box arranged for a downward flow tn
progress of the precipitation can b
e studied better, since it takes place prat
e tically at the surface.