The Ely miner., 1921-09-09

ores. QudrTy metHOuS anu SCGdlH
shovel mining, transportation by
guage railroad equipment, coarse
crushing and screening, and the mag
netic separation of the resulting
coarse material, are but steps in a
simple process. Wet grinding in
ball mills, wet magnetic separation
of the finely ground material, fill
| tering and sintering, have all been
used for years. Almost every iron
and steel man can name plants where
some of these methods have been
used, and in working out the flow
sheet for the Mesaba Iron company
these methods were combined with
the principle of the success of the
so-called ''porphyry coppers," NAM
ely the continuous automatic hand
ling of large tonnages with very
heavy and expensive machinery per-
fectly adapted to the work.
Extent of Deposits
The Mesaba Iron company con-
trols most of the magnetic taconite
of this region between Mesaba and
Birch lake, comprising an area of
between twelve and fifteen square
miles, together with much non-min-
eral land for dumps, trackage and
other industrial purposes. The Min
nesota geological survey says: "A
rough calculation indicates that the
Mesaba range from Birch lake, to
Mesaba contains about 1,500, ,000,-
600 tons of this magnetic formation
within 100 feet of the present rock
surface, without any bed rock cover"
Only small portion of this has been
drilled and accurately sampled, but
that portion contains enough to as
sure the operation of a large plant
for many years.
At a point fifteen miles east of
Mesaba the Mesaba Iron company
has commenced the new town of
Babbitt, and there some fifty build
ings complete in every respect and
equipped with water, sewer and light
ing systems, and including admin
istration buildings, shops, stores, hos
pital, dormitories, clubhouse, COM
munity hall, residences, bunk houses
and central mess hall accommodating
600 men. The plant itself is located
about mile distant on an ideal mill
site, the ground falling away to the
northward one mile and half to
Birch lake.
The first unit of a large mill is
now well along in construction and
consists of 5000 k W. power plant,
shops and mill itself. This unit will
cost approximately $3,O0O,00O, and
will have a capacity of 1000 tons
of sinter, or cGncered ore, every
twenty-four hours 1t is but the be-
ginning of the ultimate plant, which
it is expected will deliver 10000 tons |
of sinter, or clinckered ore, every
In addition to the sinter the company
will produce very large tonnage
of ideal crushed rock, the waste pro-
duct of its dry cobbing plant, and
which has been pronounced to be
an ideal material for roadmaking and
concrete aggregate, together with a
perfectly clean sand from its wet con-
centration circuit.
Using Low Grade Ores
The iron and steel industry is ap-
parently following in the steps of
the others metals, copper, lead and
zinc. In the beginning there was
plenty of high grade ore, but as con-
sumption increased it became nee
essary to concentrate the lower grade
materials In such way as to furnish
suitable and economical furnace bur-
dens. This movement has always
been fastened by increases in labor
cost and particularly by increases
IN freight rates. Costs rise rapidly
in the blast furnace as iron content
falls and it is unlikely that natural
ores alone can maintain the present
shipping grade. 1t is certain that
they cannot maintain it for more
than very few years, but if the
lower grade natural ores are mixed
with wash ores and such material
as Mesaba sinter, in sufficient guam
Titles, the present average iron con-
tent of the furnace burden can to
at least some extent be maintained
and even raised considerably. This
OF course would also result in max
ing available for preent consump-
tion natural ores which in them
selves are not at this time held as
merchantable. Some of these ores
of the lower grades can be mined
very cheaply, and by proper mixing
with such high grade material as
Mesaba sinter, an entirely satisfac-
tory average ore cost might be
maintained. In like manner, high
phosphorus ores can be mixed with
this sinter which is uniformly low
IN phosphorus, with the result that
certain ores which might otherwise
be available only for the making of
high phosphorus irons, can also be
used in the manufacture of iron OF
lower phosphorus content.
The sinter produced can be made
IN almost any quality desired frorl
% per cent iron to 20. 1t has ac-
tually been made assaying II SO per
cent iron (pure magnetic assays 72..
40 per cent iron.) The 55 per cent
material is high IN both silica and
phosphorus, while the 20 per cent
material is correspondingly low in
these same elements
As made by the Mesaba Iron CON-
pany, sinter usually contains some
hematlte, produced during the burn
Ing But even when consisting of
nearly pure magnetic there are not
the objections as have been made
against lump magnetic This is due
to the fact that sinter, r,notwithstand
ing its firm structure, is at once celu-
lar and porous, so that like coke,
1t permits free and uniform distri-
button and passage of furnace gases
with consequent good reducibility
and freedoms from hangs and slips.
Returned from Trip.