The Birmingham age-herald. [volume], June 18, 1913, SECTION B, Page EIGHT, Image 38

About The Birmingham age-herald. [volume] (Birmingham, Ala.) 1902-1950

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MINING
COAL AND ITS PRODUCTS
AND METHODS OF MINING
Different Theories Advanced as to Origin of Coal—Some of the
Properties Which It Contains—Carbon the Principal
Element—How It Is Handled
1 -
BY DICK WELLS
4 Coal and Its prodticts comprise 4
4 the most Important features of 4
4 the Industrial life of Birmlng- 4
4 ham. In nearly every one ot' the •
4 great manufacturing plants of 4
i the district coal has some bear- 4
4 lng, either direct or Indirect, 4
4 on the finished product. Despite 4
4 the Important part which this 4
4 gift of nature takes In the pro- 4
4 ress and development of this sec- 4
4 tlon, there are comparatively 4
4 few persons not directly engaged 4
* In Industrial pursuits who know 4
i nnthlng at all concerning Its or- 4
4 Igtn, the process of mining and 4
4 Its products. 4
l-:
No suitable definition for the word
coal exists. To say that anything dug
out of the ground that will burn is coal,
Is too loose to b^e considered a val
uable definition; then again to give a
definition based on the chemical analy
sis is not accurate on account of the
varied forms of coal, none of the prop
erties being identically the same.
Generally speaking, coal Is believed
to represent the remains of plant life
which has long since been buried and
lias eventually taken this form. It is
found in seams or beds, separated by
• strata of shale or grit and limestone.
Since all forms of plant life depend
upon the energy received from the
sun which fixes the carbon or carbon
monoxide in a stable form, coal may
be defined as burled sunshine. This in
dicates the great heat and energy
given off by the coal fire.
Many theories have been advanced
as to the origin of coal, some being
that the beds are dried up petroleum
lakes; others that they are sea weed
long since buried, but none of these
can be reasonably accepted. The most
logical theory so far advanced is that
when the woody fiber of leaves and
stems of plants fall on the ground they
soon oxidize or decay and the oxygen,
hydrogen, carbon and nitrogen present
pass Into the soil or air as gases, the
oxygen and hydrogen chiefly as water,
the carbon as carbon dioxide, and the
nitrogen as ammonia.
This process goes on until finally only
the ash is left, which is composed of
silica, aluminum and iron oxide. It is
for this reason that the residue of
thousands of years may be represented
by only a few inches of vegetable mould
or humus.
A dump climate and a land where the
W'ater runs off very slowly favor the
formation of swamps, though in a cli
mate as damp as that of Ireland the
moss will climb the hillside and bring
the water up for great distance by
capillary action, thus making the peat
bogs climb the hills also. The loss of
water and of carbon, nitrogen, oxygen
and hydrogen causes a great loss of
bulk. The presence of the overlying
strata which warps and changes the
locks makes the mass even smaller.
From this it can be easily seen that a
coal seam one foot thick may have been
60 feet of peat in the ancient swamp,
and the assumption may bo made that
the average coal seam is not one-fifth
the thickness of the original peat bed.
Carbon Is the Basis
Since the chief heat producing- ele
ment In coal Is the carbon, a classi
fication In wide use Is one based on
the value of coal as fuel; that Is, on
the percentage of carbon present In
the coal and also the condition of Its
carbon.
Part of the carbon In the coal Is
fixed and cannot be driven oft by heat
. Ing In a retort and part Is combined
with the hydrogen as volatile hydro
carbon compounds which are easily
driven off. The percentage of fixed car
bons is greatest In anthracites. The
percentage of volatile hydrocarbon to
the fixed carbon In a coal Is called Its
fuel ratio. On this basis the coals are
usually classed as lignite, bituminous,
seml-bltuminous, anthracite and seml
antharclte. Cannel coal in which the
percentage of volatile hydrocarbons ts
very high, Is believed to be of dif
ferent origin from other coals.
Lignite, or brown coal, is brown to
black In color though the powder is
always brown. It often shows its vege
table origin, boring stems and other
plants, which look to be In an unde
composed state. The luster is change
able for the type, the specific gravity
being 5 to 1.5, some kinds even float
ing on water. Lignites burn easily with
a very dirty smoky flame, crumbles eas
ily and generally contain a high per
centage of water and slack or even
mud on long exposure.
Different Kinds of Coal
Bituminous or soft coal is black: the
powder is black, and the luster is resin
ous or dull. Its specific gravity is 1.25
to 1.4. It has less water than lignite
and is much harder. For that reason
it can stand shipment much better than
the soft lignite. Bituminous coals are
subdivided according to their properties
or uses into coking, free burning,
smokeless, gas coal and so forth. Cok
ing coals partly fuse or melt together.
If they are low in ash and sulphur
they are used as forging coals, and for
making coke and gas. Cannel coal is
black or brownish and has a dull lus
ter; it does not soil the hand, and does
not show traces of vegetable origin.
It burns with an easy flame, is easily
ignited and is often used in the grate
I and for household purposes. But its
greatest use is enriching gas made
from other coals. It is mined in the
United States at Cannelburgf, Ind., and |
in the Jellico district of Kentucky.
Anthracite is also a black coal with j
a black powder which does not soil the I
lingers. The specific gravity is 1.3 to!
1.75. It is hard to kindle but it is
very valuable nevertheless owing to
the high percentage of fixed carbon it
contains. It burns with hardly any
smoke and with one of the most in
tense heats mado by any of the classes
of coal. It was formerly much used
In the country for the smelting of iron
but its chief use now is for household
purposes and in the grates. The less
water, ash and sulphur a coal contains
the better the coal and good coal should
not contain over 6 to 7 per cent of ash
und 7 per cent of sulphur.
Location ol' Coal Fields
North America, Asia and Burope con
tain tho great coal fields of the world.
In southern Africa, in Australia and in
New Zealand are deposits of import
ance. Only small and disconnected areas
are known in South America, and the
only mines worked on a large scale are
in Chili. As to Asia, the coal fields of
China are vast and of great import
ance, but they are practically undevel
oped. Coal is abundant In Borneo and
Burma and the output Is increasing,
sspecially from Bengal.
The United States, Great Britain and
Germany together produce about 80 per
cent of the total amount of coal mined
in tlie world.
The mining consists in getting out
as little dust as possible. The princi
pal gases found In a mine aro carbon
dioxide, heavier than air, suffocating
but not inflammable, called choke damp
by the miners; carbonmonoxlde. pois
onous and Inflammable which Is the
dreaded white damp of the mines; C.
H. 4, which is known as marsh gas,
this gas being light, non-polsonous but
inflammable, Its chief constituent being
firedamp; also but less Important, sulph
uretted hydrogen, which is poisonous
and Inflammable but easily detected by
its odor. Of all these gases the marsh
gas often given off in large quantities
Is the cause of the worst mine disas
ters. A mixture of marsh gas and atr
explodes violently when they come to
gether in the proper quantities and if
brought into contact with a flame. Coal
dust In the air makes a very much
smaller proportion of marsh gas.
Safety Device Used
To be able to work In the mines
when these explosive gases are present
HOW TO MAKE A CUP
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Illinois recently passed a law forbidding all public drinking cups and the
Chicago board of health ha^ issued instructions on how to make a 1
good drinking cup out of onlinary White paper.
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ENTRANCE TO LARGE MINING PROPERTY
(and there is no way to get them out)
a safety lamp Is used by the miners
which keeps the flame from contact
with the gases. The first one of these
lamps was made by Sir Humphrey Davy
in 1815. This lamp consists of a flame
inside of a wire gauze which makes it
safe so long as the wire gauze does not
get to the combustion point of the
gas.
Many other lamps have been Invent
ed since then, some of the latest type.'
being the wolf lamp. This lamp indi
cates the presence of dangerous gases
by tite lengthening of the flame. Car
bon dioxide and carbon monoxide are
known as ‘g'ob.M These gases are what
is known as the afterdamp, caused by
an explosion of dust or firedamp, and
are often the cause of the great loss
of life after an explosion; the victim
not knowing the danger until he has
succumbed to the gas. From this it can
be seen that to operate sucessfully
the mine must be well ventilated. This
ventilation is sometimes obtained by
a furnace at the top of the mine which
affords a strong up current sufficient
to keep the mine well ventilated. Others
are fitted with fans which draw the air
out or force the air down in making
an up-current. Various types of ven
tilators are used but the majority in
use at the largest and best mines are
modifications of the Guibal type.
Since the coal veins are only a few
$feet thick and lie flat or dip at low
angles in this country the mines can
be opened much easier than in some of
the other countries where the beds are
more irregular. The coal is taken out as
the mining proceeds, leaving air pass
ages and roadways protected by posts
or walls.
How Coal Is Sorted
Coal is broken from the face of the
seam by the miner, who undercuts it
with Ills pick and then puts in a blast
| strong enough to bring down the coal.
| Tn this country black powder usually is
I used but In some of the other countries
where there la danger of an explosion
the miner uses explosives of less flame
or even hydraulic wedges. In some
mines, mainly those in Illinois, the coal
Is blasted from the vein as oro Is mined
but this Is not as good a method ss
fine coal la not as valuable as lump
coal.
The coal when broken down Is rough
ly sorted by the miner and his helper
and then is loaded into cars which are
hauled to the main shaft by mules.
Here the cars are made up into trains
and are thus sent along tracks to the
bottom of the shaft, hence to be trans
formed to the tracks on the surface.
Occasionally coal is found so near to
the surface*hat It may be had by the
process known as stripping. Then coal
is sometimes found in pockets along
side a hill and this is known as pocket
mining.
In the shafts the chambers are dug
out to the side 30 H>r 40 feet in length
and the supports of timbers are put
under the roofs and around the walls.
After all the coal is taken out of these
veins tho timbers are taken out and the
chambers are allowed to collapse.
The coal when brought to the sur
face is screened out at many mines and
is then sold as lump and slack; but :n
others where there are many different
grades sold the coal is broken and
washed and a break is employed so as
to get exactly tlie 'size of coal desired.
Coal mining dates back to about tho
end of the twelfth century. Coal as an
Inflammable substance seems to have
been known to the ancients and to
tho Britons before the Romans in
vaded their Isle. But it was not in use
then because the forests were- so ex
tensive as to afford a supply of fuel
much more easy of access.
The uses of coal were not very great
until about the eighteenth century when
| the steam engine was brought forward
in 1705 and was applied to coal in New
castle about 1715.
Coke a Valued Product
The most useful of tlie products of
coal is the coke obtained when the
coal is heated in an oven. It may be
dellned as the cellular mass left after
the expulsion of the volatile products
of coal. In general the operation of
coke making varies little from that of
charcoal making, the only difference be
ing that the carbon molecules are
broken up more completely In the coke,
requiring a higher heat, in coking the
organic* compounds are destroyed and
the decomposition form new products
at the higher temperature. Gas begins
to come off when the charge reaches
the temperature of 100C, tho highest
temperature of the charge being 14t)0
degree (\ The time required fur cok
ing is from 18 to 72 hours, varrying
with the coal and the typo of oven.
The products beside coke are illumin
ating gas, ammonia liquor, tar and
asphaltum.
There are various types of ovens
used. Tlie oven most used for tho mak
ing is from 18 to 72 hours, varying
mice use is the beehive although it is
predicted that in (lie near future tho
byproduct oven will have completely
taken its place.
The advantage of the byproduct oven
over the beehive is the utilisation of
the byproducts of the coal besides coke.
The coke as used in the blast fur
nace is to reduce tlie ores by combin
ing with the oxygen in theirs.
The, objects of coking are to got a
fuel rich in carbons by expelling vol
atile constituents; to get a fuel giving
no gas or smoke which would Interfere
with the metalurgical operations; to
get an inf usable fuel which will not
swell or soften in heating in the fur
nace, and to reduce tho sulphur present
in coal in organic compounds combined
with iron.
High Grade Cahaba Domestic and Washed Steam Coal
MARVEL
COAL
RED ASH
Mined and Sold
Exclusively
by
ON BOTH
Louisville and Nashville
and
i
Southern Railways
Capacity,
1,500 TONS DAILY
RODEN COAL COMPANY
Marvel, Alabama
Alabama Fuel and Iron
Company
742-749 Brown-Marx Building
Miners and Shippers of
Acton=Margar et= Acmar
- High Grade Steam and Domestic
i ' •
I
GENERAL OFFICES
BIRMINGHAM, ALABAMA.
_ i.