The Ely miner. [volume] (Ely, Minn.) 1895-1986, 1924-02-29

ate in such plants, metallnrgical
losses are likely to be high, and by
no means alb the ores that can be
jigged for high grade product can
be so handled at a profit. Each ore
presents its own peculiar problem
for individual solution and in some
mines there is such wide variation
in character of ore in the same ore
body that it is difficult to see how a
concentrating plant of any kind
could be supplied with anything like
uniform feed. / am inclined to be-
heve however that several such
plants will be installed and tried out
within five years. Some of them
can be made to succeed.
Magnetic Separation.
Magnetic separation is also an old
story in other parts of the world.
Most of US think first of the plants
in Norway and Sweden, but it may
be well to call attention to the fact
that there is one plant in the
United States which is producing
$500 tons of high grade sinter
daily, made from magnetic con-
centrates. This plant is at Leban-
on, Pennsylvania, belongs to Bethle-
hem Steel Company, and is a sue
cessful and highly profitable enter
prise. Other magnetic separating
plants have operated proftably in
New York and New Jersey for many
years. Mesabi Iron Company has
had the first unit of a large plant in
operation on the Eastern end of the
Mesabi Range for more than a
year, and is now doubling its
capacity.
This is perhaps good place to
call attention to the fact that even
though the reserves of low grade
raw material-magnetite, hematite
or any other variety-are so enor-
nous, their utilization in milling
plants cannot have any serious
effect on the market for direct
shipping ores, because such milling
plants cannot possibly be brought
into quick production. BY the time
any new plant could be completed,
capable of turning out half million
tons yearly of any high grade
product (Which is approximately
one per cent of the present average
output) the normal increase in de-
mand, which has already been stated
as 10 per cent per year in the past,
would have absorbed this and
twenty times as much lower e. ade
material. Still another way to look
at this is to assume that any such
new supplies of high grade product
will simply replace natural high
10 Cd
year by year and not replaced by
new discoveries.
Low Grade Iron Ore Reserves.
The reserves of low grade mag
netic ores m Minnesota are un-
questionably large, but the hematite
reserves are far larger. Magnetic
so. far has the one important feat
ure of yielding an exceptionally high
grade product, with at the same time
a good metallurgical recovery or ex-
traction. AS against this, the hema-
tites, being softer, may be more
cheaply handled. It is among the
possibilities that certain of the fine
grained hematites may profitably be
converted into magnetic and then
separated just as are the natural
magnetites. This has been tried
commercially several times without
success, but new times bring new
conditions and the high recovery
and high grade product may event
ually prove attractive enough to
carry such a method to success.
Drying of the high moisture ores
of the Mesabi range in order to
avoid paying freight on the water
and to make a more attractive fur
mace product has been tried, and
will be tried again. A most inter-
esting phase of the ore marketing
situation might be presented here,
showing the comparative effect of
water and other elements on fur
mace practice and ore prices, but
this is being studied thoroughly by
the U. S. Bureau of Mines and
others, and their conclusions should
be awaited with all the patience we
can command.
There remain in the preliminary
class only the several methods of
agglomeration of which briquetting
and sintering are the two best
known representatives. They also
eliminate moisture, and in some
cases sulphur, but their chief aim
Is the Improvement of the physical
structure of fine ores. About two
million tons of fue dust, probably
the worst blast furnace material
there is, are being Suffered annual
ly in this country. In many cases
fine ores and concentrates consti-
tute part of the sintering burden.
There is good reason to anticipate a
considerable extension of this prac-
tice. Whether the sintering can be
done more profitably at the mines
or at the furnaces remains to be
proven.
Methods to Displace Blast Furnace.
Turning now to those methods
which do not propose to give better
raw materials to the blast furnace,
but rather to displace the blast fur
mace itself, it is necessary to be
very careful in making statements.
Iron was first made in the Catalan
forge by direct reduction from rich
ore, but this was wrought iron.
Steel can be made, and was made,
and is made, from wrought iron
but it is inconceivable that without
the blast furnace and is cast iron,
which in reality is the raw material
from which the great tonnages of
our cheap steel come, our present
civilization could have existed. The
blast furnace is an expensive piece
of apparatus, but with high overall
efficiency. Those who aim TO dis
place it hope to make steel direct
from the ores instead of making
cast iron first, then converting the
cast iron to steel. The patent Office
shows hundreds of proposed methods