Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1896-12-29
souloEas GROUND 10 POWDER.
And the Iron Particles Separated BY Huge
magnets.

Of buildings. great and small A fright
full roar comes from some of them.
From a wooden chute which JutS out
bles a grain elevator more than anything
else there drop thousands OF little black
Objects They were of the size and shape
of butter cakes. They were little cakes
of Bessemer. baked hard as flint. and
| rolling into cars ready for transportation
little black cakes mark the greatest
achievement in the career of Thomas A.
| Edison.
After years of incessant labor in study
| ing out the problem. he has now Il plant
which covers II acres. and is the biggest
mill in the world. 1t has cost him in
round figures S2,o0o.ooo He has a stretch
of mountains SO miles long as a base of
| supplies and in that has more ore than
all the rest of the United States put to-
gether.
the biggest travelling cranes ever heard
| Of His mills are SO large and powerful
that they take solid boulder. weighing
| five tons. and chew it up faster than Il
healthy small boy could eat a peanut.
He employs over 700 immense magnets to
separate the ore from the rock. The
whole process of getting out the ore is
done automatically. at the rate of 5000
tons day. and the finished product is
put into the cars, ready to be shipped. at
a cost of IS cents a ton 1t costs almost
| So a ton to get the richer ore in Penn
| sylvania.
Mr. Edison's system pays net profit of
| Il per cent. on the capital Invested NO
| bonds have been issued, there Is no mort
| gage on the property, and everything has
| been paid for.
| Mr. Edison first conceived the idea of a
magnetic ore separator about 10 years
ago. Al odd moments, he constructed Il
small model. which satisfied him that the
plan was feasible, aud was laughed at by
everybody whose opinion. was considered
of value in such matters. So confident
| was Mr. Edison that the idea could uiti-
mately be worked out that he began to
look about for the ore. He started out,
| armed with magnetic needles. to find a
rock that contained the iron crystals.
He visited all the mines in the New
Jersey mountains, and after being out SIX
| weeks noticed rock which looked like the
| gneiSs. common in the state OF New YORK.
They followed up that rock. ana got
quite a detection of the magnetic needle;
| Continuing they found lots OF rock OF
the same character, and that landed them
| in the neighborhood which is now known
as Edison. He found there stretches of
the gneiss Az miles long and 1000 feet
wide. 1t stood up vertically aud extended
down into the earth two miles or more.
| Right at the mill there is now one piece
| Il mile long and 400 feet wide and an
other that is two miles long and POO feet
| wide. Each of these bodies OF gneiss con
| tains Is per cent, of oxide OF iron. ~,
Mr.. Edison has leased and bought all
those stretches OF rock. so that his base
of supplies is 50 miles long. Right on the
mountain on which the mill is located
there is available 2oo, 600 tons of oxide OF
tically unlimited. it doesn't take long to
| get an idea of the value of the ore-pro-
ducing mills. The gneiss is got out of an
| open quarry 5000 tons at clip.
When the rock has been blasted a tray
cling crane 900 feet long and worked by
electricity on the trolley system rolls
down over the loose rock. There are big
claws attached to it. and by means of
these the chunks of rock. no matter how
large are hoisted on flat iron buckets,
| called "skips" which hold four tons each.
H.. rpllnrc of rha mill a chilled
iron six feet in diameter. and the surface
runs at the rate of mile minute. They
weigh 1904 pounds each The mills are
run at such high velocity and have such
power stored up behind them that the
biggest chunks of rock check them only
five per cent; They are driven by fric-
ton. and strike terrific blow.
There are five mills in all. The first
one grinds the rock into particles Is
inches in diameter; the second. TO eight
inches: the third. to three and half
inches; the fourth. TO two inches and the
fifth. to one-half inch smaller. It runs
from one mill into the other and when
| a rock is first dropped in. those who are
not familiar with the process imagine
that the whole mill is going to burst TO
pieces at once.
| square tower. where it strikes one hot
plate after another in descending. and is
dried at the rate of five tons minute,
From the drier it passes into stock
house. where it is kept until used. This
| stock house holds l5,000 tons.
There is a series of openings in the bot
tom of the stock house, which open into
"A conveyor. The conNeyOr Is simply a
series of pans about the size of an or'li-
nary sink. drawn by an endless chain
running on little tracks. The conVeyoi
takes the ground material to another
mill where it is ground to pin-head size.
| Leaving that mill it runs through chutes
and through screens at the top OF the
high building in which the magnetic
Separa tors are located.
There are three sets of the ma SnetS-
a in the first set. 800 in the second, and
$40 more in the third set The magnets
are about four feet long, and the ore. on
its journeyings. has 10 pass mile OF
faces of magnets. Right here is pre-
ksented what to the layman is most re-
4 markable feature of the process. The
magnets are arranged in tiers. five in a
tier. The top one is weak. but they in
crease in strength as they go down, until
the bottom one is very powerful
The ground rock passes through the
screen and starts downward in front OF
the magnets. Magnets jerk the par
ticles of iron oxide from the mass as they
descend; but the iron does not adhere 10
the magnets. And right here is a most
surprising sight. The ore. in passing the
first magnet inclineS toward it, As il
rushes down. the ore swings in more to-
ward the magnets. until. as it reaches
the last one. it curves inward and under
ii in a half circle, without amy particle
of ore adhering to the magnet.
In its first passage past the magnets
small quantities of stone stick to the ore.
The ore is carried upward and started
down before the second lot of magnets
after passing through a mill which srinds
off the particles of stone The first set of
magnets extract 81 per cent of oxide of
iron. When the mass has passed the
second set of magnets there is i'll it o
per cent. of oxide of iron. Then it is
ground again and passes the third and
most powerful set of magnets, which
takes the phosphates out and makes
Bessemer of it. The percentage OF iron
oxide is then from 50 to 81.
From there it passes to Il second stock
house which holds % 600 tons. The Besse-
mer is drawn out as wanted. 1t has
passed through all the processes auto
maticaly. Men are employed. but only
to watch the machinery.
4 The little black cakes are called
briquettes. and are made in separate
plant. There are a number of machines
which make them. and the process is Just
as interesting as any other part of the
work.