The Salt Lake tribune. [volume] (Salt Lake City, Utah) 1890-current, 1906-07-23
Plant Is Interest ting Because
System Requires Use of
Little Water.
SHERMAN METHOD is
HERE DEVELOPED
Eastern Journal Describes in
Detail Plant of Great
Utah Company.

terestin6 because 1t is here that L. W.
Sherman developed his system of mill
ing, one feature of which is the small
amount OF water used, says tho Engi-
neering and Mining Journal Another
principle Is never to reject tailings un-
til they have been retreated at least
once. Jigs arc good coarse concentra-
tors, but ho does not roJect talhngs
from jips. Mr.. Sherman has also In
vented a system of classifying tanks,
with which he effects close classlhca-
tion Of pulp and treats each size on
separate table or sinner. The middling5
from the tables are re-concentrated on
other tables or else sent back to the
classifying system. because middlings
from the tables Of this mll-treating
classified pulp-are due not 30 much to
attached fragments of lighter minerals
as to the fact that the small grains of
the heavier minerals wash under the
coarscr particles of the lighter, pro-
ducing q middling band which can be
separated by re-treatment, without in
termedinte crushing.
The mill discharges no more water
than is absolutely necessary to wash
away tailings. 1t treats 400 tons of ore
a day and discharges only 40 gallons
Of water per minute with tailings, al
though about $50 gallons per minute
are flowing through the system. The
overflow wnter from the classifiers Is
used as wash water on the tables, for
Jig water, and also in regrinding the
dewatered Jig tailings. By this meth
cd Mr.. Sherman effects saving Of
over 95 per cent Pb [by wet assay,
1880 per cent Ag, and about so per
cent In upon an ore which averages
4.5 per cent Pb, lib ounces Ag, and
90 per cent I'm. Much Of the lost silver
silver chloride which occurs In the up
per levels. To make a high saving Of
zinc is not attempted at present, but
another mill for saving the zinc values
is already planned and its erection is
contemplated as soon as the Ontario
drain tunnel is reopened.
The mill contains number of novel
devices, OF Mr.. Sherman invention,
which appear to be quite good. The
springs that hold the rolls up to their
work are kept under tension by nut
screwed up tightly against series of
nine rubber discs, one inch thick, sep
arated by sheet-iron plates. These are
compressed so that the rolls are rigid
while crushing ore, but, if a piece of
iron gets between them they will open
about ~ or 2 inches. The old type
Of Huntington mill has been improved
mechanically and by the addition of
new principles. The stem to the muller
rotates in an oil bath entirely pro-
tected from grit and dirt. These stems
now extend above the yokes and are
connected with turnbuckles and tension
springs, whereby the mullers are held
lightly against the die ring. No at
tempt is made to increase tho capacity,
but only to cause the mullers to work
smoothly against the ring, for then
they wear round instead Of rough, as
they do in the old style Huntington
mill. Then, too, in case Of any tenn
-porary overlooking, the tension in the
rods prevents choking.
The Sherman classiier is an outside
cylindrical tank with conical bottom,
inside Of which is q steel cylinder
whose section area IS just half that
of the annular space. The inside cylin-
rim 6 inches higher than the outside
cylinder. The inside cylinder does not
extend down to the bottom Of the out
side one. The pulp is admitted to the
center cylinder and passes down
through screen (put there to keep
out sticks, etc., then up through the
annular space and overfows to cir
cular launder around the outside of the
outer cylinder. This discharges to a
similar tank which has twice the area
OF the tank preceding it,
The Sherman table is an improve
ment on the old Hooper sinner 1t
consists of twentyfour trays, each l
I 2ao =
by side to form an endless belt which
travels over sprocket wheels at each
end Tho first four of the trays are
given bump and jar which tends to
throw the material toward the head Of
the tray and also has the effect of
stratifying the material as In an old
Cornish dolly tub. Tho surface of the
first trays being tho most elevated, the
end of the last tray the most de-
pressed, while the middle tray is level
The other seven trays of the top deck
are given yannmg motion which
washes off the top of the bed, strait
fed by the jarring motion of the first
four trays. The device which gives
the reciprocating motion operates in
an oil bath and is placed above the ia
BILE out of the way of any splash The
trays have piece of hnoleum at their
head ends, whore the feed pulp comes
on, but the Ded OF the trays ls lined
with canvas.
There are two troughs under the dis.
charge ends of the trays, one for the
middlings and the other for tho tails,
Middlings come off the first two trays
before stratifcation has been effected,
and also off the last few trays when the
top LAYERS of the bed are being washed
off, The point where to cut out the
middlings is determined by panning
the tailings coming of the different
trays. The heads are washed off the
trays by a Jet of water coming from a
perforated pipe placed under the end
of the table. The method of keeping
assay results at the Daily West mill is
unusual. Fire assays are made from
daily samples of the ore. A proper.
tion of each daily sample is kept for
making up a weekly sample which is
assayed by the wet method
This sample is made up by weighing
out from each daily sample the pro,
portion represented by that day in the
weekly run. The weekly samples are
saved and combined In similar way to