The silver messenger. (Challis, Idaho) 1890-1912, 1900-04-24
ORE coNcENTRnT,on
''oS Phases of the Process c.r.,.u.
Considered.

in,nas, says that In his opinion 10
mpIoyeinent over existing metho6s
nployed In the district are needed
NOoAcehtrating," he says In the War
~ann,i 10 make a clean product re.
saruless of making a close SAVING 90
All lhe values that can he eosiIv
% ~ eneaply had by concentration and
y use or cyllde for the final treat
nient VIII in nearly all cases get from
nlpely-nYe to ninety-nine per cont ~
.ne values. Clean CONCENTRATES ara :
very desirable product for the smell.
all anu nave no doubt they win do
of nu can 10 encourage this system
an mllling, There is no excuse now for
& soOd and well located concentrat-
ny mil to stand idle. The addition Of
q cyanide plant fills the missing link
we nave made very extensive tests
On this line here in Boulder county
anu always with tirst-class results. Ii
- very safe to say that n method
mat VIII handle Boulder county ore
VIII answer for any other ores pro-
duced in this state. Our tests show
u a with a wellequipped concentraf-
ing mill and cyanide plant of fifty tons
per day capacity low-grade ore can be
-
converted into money at an expense
not exceeding $1.5c per ton. In the
TWO opera lions of concentrating and
cyanlding nearly full assay value is
saved. This $1.50 per ton will include
the expense of shipping and smelling
charges on the concentrates
In some ores the heavy sulphide ma
terial does not carry the highest value.
the gangue being richer than the con
centrates, but such instances are com
paratiyely rare. There are mines. too,
wherein are found both Hgh-grade and
low-grade sulphides, and unless these
can be distinguished and separated in
the mine the low-grade material will be
saved on the concentrators, together
with the high-grade, reducing the aver
age value. If the lower grade sulphide
contains sufficient value to pay for
treatment at the mine, or for treatment
at the smelters, it makes no difference,
but. not containing such value, the low
grade material should be separated. if
possible, from that containing the high
grade. Where there are two clearly
recognized classes of ore occurring in
a mine, each Of different character and
NAAAis anu AElG NaNu Gdn DE EASILY
mined separately. their treatment in
separate batteries would give better re
suits than if these ores of differing ma
terial or value were mixed and worked
together.
There are, however, few mines where
the ores, having sufficient value to pay
for the cost of mining and milling, and
containing sulphides as well, do not
justify concentration, and as, in the
greater number of such cases, the sui
phides contain higher value than an
equal weight of gangue, clean concen-
tration is desirable, f0 he reason that
an admiXture of the relatively worth
less sands reduces the grade of the con-
centrates, and transportation and re-
duction charges have to be paid on a
quantity of material containing no val
ne. or at least a value below the cost
of transportation and treatment.
1t is true, concentration may be car
ried mechanically beyond the limit OF
economy, and when the point is reach
ed where closer concentration does not
result in profit it should cease.
Sorting by hand is a rude concentra'
ton and should be regulated by the re
suit. If the silicious portion is suscep'
tible to profitable treatment at the
mine. it should not be sent to the smell
ter. where the cost of transportation
and treatment is higher. On the Other
hand. if the cost of more closely hanC
sorting this ore is greater than the cos
of transportation and smelling, theI
close hand sorting should be discontin
ned. 1t often occurs that the gangut
remaining in hand-sorted ore, which
might be treated at the mine at a proht
does not contain sufficient value to pa!
for shipment and treatment charges
which makes the situation sui worse
but the fact that such gangue doe
contain sufficient value to pay ines
charges and possibly leave a proht zoe
not Justify its shipment when II may U
~hand-sorted and treated at the min
with greater profit. /.
At most mines where hand sorting
nracticed the ore is broken down VIII
hammers by a number of cheap mel
who laboriously break and almost me
chanically separate the high-grade sul
hid from the gangue. Necessal
ilv this process, unless carried to a
oytreme and expensive point, leaves
Iorge amount of ore in the selected OF
sacked for shipment. 1t is cheaper
and will afford much more satisfactor
results. TO run the ore through a breaf
or and. if necessary, through a SET Q
rolls.
Orc in which the high values occur
launches or ribbons of sulphide mat'
rial in a gangue of quartz, calcl,'
harvta or other material may usuall
he cheaply hand-sorted. as suggesee
ohove when the ore is first DrougI
srom the mine it should be dumpe
onto a fiat grizzly made OF rallroa
tnon or heavy bars set half inch apar
The ore should be washed by a slreal
If wafer from a hose, the tine mateti'
nassing through the grizzly IN d W
- hin beneath. The large masses, no
Ha;ng clean. may be picked over :
ppond and often a quantity OF clea
n"inbide mineral obtained, whlle
eunph hreaking with a hammer WI
often result in the recovery u az
mora The remaining ore snoulu the
hO sboveled off the grizzly into a g
49, ond sent to the breaker, passin
uh;oh a stream is again turned on
nc ore cleaning it for further nan
sort;ng The solid pieces OF suipIlI
mineral may here be quickly pi pr =
ort the remainder going to the mn L
Uod,,ction and mechanical cohcentl
Ion A grizzly similar to the nrst m q
.o no nroyided at the breaker II