The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1914-04-16

The preliminary runs at the Ma
tional mill at Mullan this week have
proven very satisfactory to the man
agement. While the entire mill is no,
in operation, and Will not be for sew
eral days, the demonstrations made
are enough to prove the success Of the
method used. Concentrates are now
being made from the Deister and Will
fley tables only, the new flotation pro-
cess not having yet been fully in
stalled. This part of the process will
however, be In working order within
a few days. The mill feed is ground
to 30-mesh for the tables and to CO.
mesh for the flotatlon process. The
flotation plant Is one of the new
methods being put out by the Callow
people, and Is one Of the first plants
Of Its kind to be installed in the
United States. There are ten ma
chimes In the group, 8 for the first and
2 for second concentration, all Of
which have been turned out by hand.
The machines have been thoroughly
tested, however before introducing
them into the National mill and the
inventors claim for them decided
success.
The mill building Is constructed of
solid concrete foundations from top to-
bottom, while the framework is of
timbers covered with corrugated zinc
sheeting, making the building as solid
and as nearly fireproof as possible.
The mill Is Of 800 tons capacity, and
Is so constructed that any number of
other units can be added on to it as
the capacity Of the mine may re-
quire.
The power for the mill is electric.
divided into units composed of indi-
vidual motors on each floor of the
building of the required power neces-
sary to drive the individual ma
chimes or line of shafting attached to
them.
Starting at the top Of the mill, the
ore travels from the bins over belt
conveyors to the crusher, huge Tray
lor machine, manufactured by the
Traylor Engineering and Manufacture
ing company Of Allentown, Pa. From
the big crusher, the ore passes to two
sets of Chalmers Williams rolls and
one Simons crusher for fines. The
motive power used for these two
crushers and two sets of rolls is
Westinghouse electric motor Of 200
horsepower, 1900 volts, so cycles, 8
phase
From this floor the feed passes into
huge bins to Hardinge Conical ball
mills, driven by 800 horsepower
General Electric company motor with
rope drive. With the conical ball mills |
the National company has developed /
. new principle in milling practice
that OF using their own ore for grind
ing material instead Of the expensive |
imported flint pebbles in use in other
Mills Of the district. The ore is in
Unity hard Revett quartzite, and this T
material. broken to the proper size,
3 fed to the ball mills in place of the
lint pebbles for the purpose of grind
ne the finer material from the rolls.
'he company estimates a saving of
t least two cents per ton by this
Method. eliminating both the cost of
he pebbles and the cost of picking
hem. The wearing away Of the
uartzite grinding pebbles is no waste
Material. as would be. the costly flint
ebbles, for the reason that 1t is the
ime kind Of ore that 1t Is assisting to {
rind.
From the ball mills the feed passes
yer sets Of travelling Callow screens t
the table floor where the first con- J
Of values is made. The {
achlnery on this floor is driven by |
80 horsepower Westinghouse cleo c
ic motor. Here the feed passes over e
NO. Deister Concentrating tables 1
anufactured 10y the Deister Concen- t
ating company Of Fort Wayne. Ind,
ia also ove, 10 Whitley No. tables, d
aplfacture by the Mine & Smelter g
ipply com pany of Denver Colo. The n
ncentrates from these tables is G
liked black copper glance and chal- c
'pyrite, which is delivered directly d
ON the tables to the loading bins II
low. +,
The tails from these tables are next W
used through ball mills and reduced Il
6O-mesh, from where they go to the 81
wv Callow flotation process They &c
e first delivered to two big agitation
IT'S, and from there into two acid Ell
citation tanks, where compressed air T
Finished by small single stage type ~
Z. SxS Tngersoll- Rand compressor p
applied. together with steam and &c
rpentine and oils used in the meth w
!. This part of the system is driven Sc
30 horsepower Westinghouse mo- be
r. From these tanks the feed passes al
the acid flotation machines, s in st
mber for the first part Of the pro- w
IS. These machines are built of tn
ANY iron, and form small tanks ar
out 4x12 feet and about feet deep an
the upper end. The bottom of each
nix forms steep incline from the
p to the waste discharge end, and
Is bottom is covered with a porous
lanket" made of some coarse heavy FRI
brio. The tank is divided by parti- Ca