Great Britain, but she is destined to become eventually the great
coal producer of the world. At the present time there is much anxiety
in England about the exhaustion in a few hundred years of the coal
fields in the British Isles. The United Kingdom contains nine thousand
square miles of coal fields; France, Belgium, Spain, Prussia, and
other German states, together, about two thousand seven hundred
square miles of coal fields; other countries, not including America,
contain about twenty-nine thousand, while North America, including
the British colonies, contains about one hundred and eighty thousand
square miles of coal fields. It will thus be seen that the area of
the North American coal fields is four times as great as all those
of the other countries of the globe. Of this immense extent of coal
deposits, a very small portion has yet been touched, and consequently
for thousands of years to come our country can supply the world.
[Sidenote: HOW COAL WAS FORMED.]
Coal was formed at a very remote geological period. Scientific men
differ as to the exact age of this substance. Their differences are
trivial, however, being only a few millions of years; but they all
agree that at the time coal was formed there were wide jungles and
swamps that covered a large portion of the earth’s surface. The
atmosphere was very moist, and probably contained a much larger
proportion of carbonic acid than at the present time. This gas is
one which especially promotes the growth of plants. It is, and was,
probably unfavorable to the existence of animal life; and it has been
suggested that the gradual withdrawal of the carbonic acid by the
growth of vegetation of that period slowly purified the atmosphere,
and brought it to the condition in which we now find it. The earth at
that time was not fitted for the habitation of man. If man had existed
at that period, he would have needed fins in the place of hands and
feet, and would have required lungs like those of fishes, instead of
those which he now possesses. There was an abundant population of
reptiles and of insects, and there was a liberal supply of fishes.
Many of these fishes, reptiles, and insects are unknown at the
present day. They performed their work, if work they had to do, and
disappeared. Their remains are found in the coal seams and in the
rocks which lie above or beneath the coal, and form an interesting
subject of study.
Some of the reptiles were enormously large. Remains have been found of
a lizard more than one hundred feet long, with an open countenance,
that could have taken in an ordinary man about as easily as a chicken
swallows a fly. The skeletons of these reptiles are found, and I think
that most people who examine these skeletons are inclined to give a
sigh of relief when they remember that such creatures are now extinct.
They would be very disagreeable travelling companions, and one might
be very much disinclined to meet them in a narrow lane on a dark night.
Some years ago I examined the skeleton of a reptile discovered in the
Mississippi Valley, and though the bones were cold and motionless,
I had the wish to keep at a respectful distance from them. He had a
mouth that reminded one of the extension top of a patent carriage;
and when his jaw was pushed back, it seemed to me that he could have
walked down his own throat without the slightest difficulty.
[Sidenote: CONVERSION OF PEAT TO COAL.]
The most plausible and reasonable theory of the formation of coal
seems to be that it is for the most part the remains of vegetable
matter which had become decomposed and changed to mineral on the spot
where it remained and is now found. The fibrous tissues of the aquatic
vegetation flourished like a thick carpet on the moist surface. It
became mingled and matted together, as we now find turf and peat in
peat bogs, and in swamps and marshes. On the borders of great lakes,
which in time were built up and became swamps, these plains extended,
and underwent slow depression. Layers of sand and other substances
were carried down below the level of the sea, which we now find among
and alternating with the coal seams in the shape of beds of shales
and sandstones. Then another system of lagoons formed above them, and
allowed new jungles to spring up and new marshes to be formed. These
were in turn depressed and covered by the waters. In this way, step by
step, the coal beds were built up. According to geologists, each coal
seam represents a depressed swamp, while the intervening strata of
sandstone, and shale, and clay, mark the various sediments which were
brought together by the action of the waters.
The coal beds contain many impressions of plants and portions of
plants, so that geologists have been able to determine the nature
of the vegetation of that period. There are a great many mosses
and ferns, some of the latter having thick, broad stems, and long
and heavy leaves. One geologist says there are one hundred and
seventy-seven specimens of plants found in single coal beds. He says
there are no palms, nor grasses, nor flowering plants; and for this
reason he considers that the coal beds were formed from plants of a
marshy growth.
The layers of peat, after being covered by shales, sandstone, and
limestone, were compressed beneath the enormous weight of the
over-lying strata, and while undergoing this compression, there was a
sort of distillation and purifying process going on. In this way the
plants and peat, originally loosely matted together, became more and
more compressed, and by means of the heat and pressure were entirely
decomposed. Ultimately the substance was turned into what we now find
it, and the coal was stored up for future ages.
The ancients had curious theories in regard to the formation of coal.
They regarded it as streams of bitumen, which had become petrified,
or had impregnated certain very porous kinds of rock. Another theory
which they entertained was, that forests had been carbonized on the
spot where they grew, or had been transformed by streams of sulphurous
acid, which possesses the property of hardening and carbonizing wood.
It is easy to attribute the origin of coal to the agency of rivers of
bitumen, and oil of vitriol; but it is not easy to say where those
rivers came from.
[Sidenote: SACRED FIRE WELLS.]
The Chinese have a theory that coal is a species of plant of which
the seed was deposited in the earth ages and ages ago, and that it
grew and spread in different parts of the empire where it is now
found, in order that the Chinese of to-day might have a sufficient
supply of fuel. They attribute the streams of inflammable gas, which
they collect and utilize, to the breathings of an immense monster
below the surface of the earth, and in some localities they call him
the first cousin of the God of Fire. The God of Fire is one of the
Chinese deities. He occupies a prominent place in the temples, and is
worshipped with great solemnity. In other parts of the world these
streams of gas are worshipped, and in localities along the coast of
the Caspian Sea, streams of burning gas are constantly rising, and
their sources are known as sacred wells. They are visited by thousands
of devotees every year, and are regarded with the greatest reverence.
Wells of similar character exist in the United States, but they are
mostly of artificial origin. They are found in the vicinity of Oil
Creek, and that region of Western Pennsylvania which has been baptized
as Petrolia. Thousands of devotees have worshipped in the vicinity of
these wells, and many of them owe their fortunes to the modern God
of Fire; but it is doubtful if many of them worship the wells with
that religious devotion and reverence which are found among the fire
worshippers of the far east.
[Sidenote: A WIRE TRAMWAY.]
A novelty in the way of carrying coal may be seen at the Harewood
coal mine, at Nanaimo, British Columbia. The mines are situated at a
considerable elevation above the sea-level, and the intermediate
ground is covered with trees and rocks, while several deep ravines
intercept the grounds. Under such circumstances, the construction of
a railway would be costly and require much time, as several viaducts
would be required, and the road at some places would have to make
considerable curves. The proprietor of the mines therefore decided to
avoid all these difficulties, on putting up a wire tramway in a direct
line from the mine to the port, by means of which the ravines could
be spanned without expense, and the timber on the ground could be
converted into the necessary posts.
There are in all ninety-seven posts, put up to such a height that the
wire spanned over them forms a softly inclining plane. The distance
between them is from 150 to 250 feet. The wire rope is of the best
crucible steel, specially made for the purpose, and is 6-1/2 miles
in length; each post having a pair of groove-pulleys two feet in
diameter, over which the wire moves. The rope is driven at the lower
end by an engine of 20 horse-power, which is sufficient to drive the
line when carrying 12 tons per hour.
The driving machinery is fitted with drums 10 feet in diameter; at
the mine the rope simply passes round a 10-foot drum. Two hundred and
fifty iron buckets, each with a capacity of 2 cwt. of coal, are fitted
with a patent hanger and box-head, by means of which all jolting,
when passing over the supports, is avoided. This tramway has been
transporting, during eight months, about 120 tons of coal per day, and
no accident or stoppage has occurred.
[Illustration: WIRE RAILWAY AT THE HARWOOD COAL MINES, BRITISH
COLUMBIA.]
Many other tramways of the same nature have been recently put in
operation in various parts of the world, as, for instance, in
Mauritius, where they have been successfully applied to the carriage
of sugar-cane; also in New Zealand, where they are used for carrying
manganese ore.
[Sidenote: ESTIMATE OF COAL.]
This means of conveyance is certainly a very practical and inexpensive
one; it does away with railroad material, engines, engineers, the
consumption of coal, etc., and may be applied over the deepest
ravines, where it would almost be an impossibility to build a
railroad, unless a bridge were built, at enormous expense and labor.
Let us conclude this article by giving the following estimate, in
round numbers, of the world’s present annual production of coal. It
is taken from various sources, and may be considered approximately
correct.
Tons. Per cent.
Great Britain, 127,016,747 46.4
United States, 50,512,000 18.4
Germany, 45,335,741 16.5
France, 17,400,000 6.4
Belgium, 17,000,000 6.2
Austria and Hungary, 11,000,000 4.0
Russia, 1,200,000 0.5
Spain, 570,000 0.2
Portugal, 18,000 ———
Nova Scotia, 1,051,567 0.4
Australia, 1,000,000 0.4
India, 500,000 0.2
Other countries, 1,000,000 0.4
————————— —————
273,704,055 100.0
III.
BORINGS AND SHAFTS.
HOW COAL MINES ARE DISCOVERED.—OUTCROPPINGS.—SCIENTIFIC
RESEARCHES.—HOW A MARBLE QUARRY WAS FOUND.—BORING A WELL, AND
WHAT CAME OF IT.—A LOCAL DEBATING SOCIETY.—INTIMATE RELATIONS
OF COAL MINES AND THE STEAM ENGINE.—STRIKING OIL.—“DAD’S STRUCK
ILE.”—THE UNHAPPY MAIDEN’S FATE.—COAL INSTEAD OF WATER.—THE
TOOLS TO BE USED.—A DEEP HOLE.—TERRIBLE ACCIDENT, AND A MINER’S
COOLNESS.—SINKING SHAFTS.—AN INGENIOUS APPARATUS.—ACCIDENTS IN
SHAFTS.—REQUIREMENTS OF THE LAW.
Until the beginning of the present century coal mines were discovered
more by accident than in any other way. The coal seams make their
appearance at the surface, that is, they “crop out,” or “come to
grass,” as the miners say. Coal on the surface is generally of a poor
character, for the reason that it has been for many hundreds of years
subject to the action of the elements; but on digging down a few feet,
or a few dozen feet, the quality is found to be greatly improved.
When coal is thus found at the surface, a preliminary examination
is conducted by cutting trenches, galleries, and pits, and if the
conditions are favorable, the actual working of the mine can begin.
Sometimes the mine is operated by a few cuttings, like the works of an
ordinary stone quarry.
[Sidenote: DISCOVERING COAL MINES.]
Most coal mines have been discovered and opened in this way; but when
the coal is concealed beneath the soil, and nothing is observed on the
surface, it is discovered by chance, or by geological indications. At
the present day many coal mines are discovered by means of railway
cuttings, or in sinking wells. Other mines are discovered in this way.
Some twenty years ago, while a railway was constructing in Vermont,
the workmen came upon a bed of marble, and it was found to be quite
extensive. Speculators bought the land in the vicinity, and thus the
Vermont marble quarry came into existence.
In 1813 a well was sunk at La Sarthe, in France. Amongst the rubbish
a black earth was noticed, which was sent to a provincial debating
society at Le Mans. An extraordinary meeting of the society was
called, and somebody suggested that this black earth might be coal. It
was immediately tried in the stove in the room where the meeting was
held, and it was found that the earth burned readily. An investigation
followed. Careful examinations were made, and valuable coal mines were
opened in the vicinity.
Some of the mines in the United States have been discovered in places
where burrowing animals had thrown up the earth. Decomposed coal
retains its original blackness; in several instances where it was
found in the earth thus thrown up, careful observations were made, and
work was immediately begun in search of coal. Some valuable mines have
been opened in this way.
Many of the coal mines in France and Belgium, and also in other
countries, have been found in consequence of the explorations of
geologists. In the year 1716 a very skilful coal miner in Belgium made
a series of explorations, and discovered very valuable mines. Under
his direction they were explored for several years, but the works were
at length abandoned, in consequence of the accumulation of water. In
all parts of the world miners have always found great difficulty in
proceeding in consequence of the interruptions caused by water, and
until the steam engine was invented there was an absence of sufficient
power for its removal.
[Illustration: ENTRANCE TO A COAL MINE.]
[Illustration: DOWN IN A COAL MINE.]
[Sidenote: INVENTING THE STEAM ENGINE.]
In the eighteenth century deep pits in the Newcastle coal fields were
filled with water, and it was necessary to drain these pits before the
coal could be taken out. The ordinary pump was not sufficient for the
purpose, and a more powerful engine became necessary. Inventions seem
to come at a time when they are most needed. When the necessity for
a powerful pump was greatest, the steam engine was invented. Savery,
Newcomen, and Watt succeeded each other. Captain Savery constructed
one of his “fire engines” to lift water from one of the Cornish mines;
but the power of the engine was not great, and the quantity of water
raised was exceedingly small.
Newcomen invented the atmospheric steam engine, in which the piston
was lifted by steam, and when this was condensed the piston was forced
to the bottom of the cylinder by the pressure of the atmosphere.
Afterwards Watt improved upon the engine, and overcame the difficulty
of removing the vast accumulations of water in the deep mines, about
the middle of the eighteenth century.
There is a curious relation between coal mines and the steam engine.
The latter was invented among the former, and without its application
to pumping purposes the invention would have been to a great extent
worthless, for by means of the very substance raised from the mines
the engine is kept in motion. The mines thus furnished the material
with which the engine is operated, and only with the aid of the engine
can the coal mines be properly worked.
In the petroleum regions of America the borings and pumpings are
frequently conducted by means of the gas which rises from the earth.
Very often a steam engine is run without any other fuel than a stream
of natural gas, conveyed beneath the boiler, and fed through a proper
distributing apparatus.
To the coal mine we are also indebted for that great boon of modern
civilization, the railway.
Coal is a heavy, bulky article, selling at a low price. Not only must
it be removed from the earth, but it must be carried at a cheap rate,
and often for long distances. Where there is no water communication
the roads are the only mode of conveyance. Originally common earth
roads were used, and the coal was carried in ordinary carts. These,
roads were improved, and, after a time, were in the condition of stone
causeways, or macadamized tracks. Afterwards wooden tracks were used,
over which the wheels would roll more easily than upon ordinary roads.
These wooden tracks were at first placed in the underground ways of
the mines, and afterwards extended to the ways above ground.
[Sidenote: INVENTION OF THE RAILWAY.]
But wood is not durable; it soon rots and wears away. The wooden
tracks were subsequently replaced by others of cast iron; originally
these were grooved, but subsequently they were furnished with a
lateral flange. Afterwards wrought iron was substituted for cast iron.
In the first instance strips of cast iron were placed upon wooden
rails, forming the old-fashioned strap rail. Afterwards was invented
the ordinary rail as we now find it. The flange was removed from the
rail, and placed upon the wheel, and thus, step by step, the modern
railway came into existence.
Something more was wanted. Cars were propelled by means of horse
or man power. It was necessary to apply the steam engine to the
work of transportation. Trefethick, a Cornish miner, constructed a
locomotive with a simple boiler, like that of a stationary engine; but
the heating surface and the motive power were too small. It was not
then supposed that the wheels would turn upon a smooth rail and move
forward, and so the driving wheel was toothed and worked in a rack.
The speed was less than that of a carriage drawn by horses. George
Stephenson, an old coal miner, completed the locomotive.
Seguin, in France, about the same time, invented the tubes which run
through the locomotive boiler, and afford a passage to the flames.
They greatly increased the evaporating surface, and consequently the
production of steam. Stephenson discharged into the chimney the steam
which had acted upon the piston, and thus gave a great draft to the
furnaces. The locomotive was then complete, and since that day it has
only been improved in its details.
We have wandered a little from the search for coal to speak of the
steam engine, the locomotive, and the railway.
[Sidenote: BORING FOR COAL.]
Many coal mines have been discovered by borings in search of artesian
springs. About thirty years ago, in one of the French provinces,
a well was being bored, and, quite unexpectedly, the boring tools
revealed the presence of coal. As soon as this became known, everybody
went to work searching, not for water, but for coal. In a region sixty
miles long by twelve or fifteen wide, the ground was perforated
like a sieve, by a series of borings which were laid down on a plan
that seemed to resemble a constellation of stars on a celestial map.
Everywhere coal was found, and altogether one hundred thousand acres
of coal fields were added to the wealth of France. Nearly thirty
companies were organized to work the new mines. Since the discovery
about fifty pits have been sunk, some of them to a depth of five
hundred yards. In 1851 the mines produced five thousand tons of coal.
At the present day their product is not far from twenty millions of
tons. All this originated in a search for water.
The process of boring for coal is very much like, in fact almost
identical with, boring for petroleum. The boring rods are of wood, or
iron, and are screwed together as the work proceeds. The primitive
instrument is a steel chisel, or bit, which strikes the rock and wears
it away, precisely as an ordinary drill makes a hole in a stone ledge.
Boring machinery may be operated by steam power or by hand. In the
primitive way, a triangle, or pair of shears, supports the rods, and
has an ordinary windlass, by which they may be raised or lowered.
One of the inconveniences attending the ordinary process of boring
is, that the rock is pulverized, and nothing but little fragments of
dust and mud are brought to the surface. Sometimes it is difficult
to determine whether the stones through which the borer has passed
are the proper ones to indicate the existence of coal, or whether the
black matter comes from coal or shales. All these disadvantages have
been overcome by means of a new instrument, which is in general use.
A gouge in the form of a hollow cylinder is employed, furnished at
the base with a row of teeth, or with several cutting blades of cast
steel, and sometimes with a row of diamonds. It is worked like an
ordinary borer or auger, and cuts a solid column or cylinder out of
the rock as regular in shape as if it had been turned in a lathe.
When this cylinder has been cut to a sufficient length, it is broken
off by means of the gouge bit, or grapnel, which seizes it and brings
it to the surface. The boring tool will cut a hole eight inches
in diameter, leaving a pillar of rock in the centre which can be
broken off at any desired length and brought to daylight. By means
of this rock, the fossils in the stone may be studied, together with
the structure of the strata, and all its peculiarities. Beautiful
specimens of rock are frequently obtained in this way from great
depths. Some borings have been made to a depth of nearly two thousand
feet, with a diameter varying from eight to twenty inches.
As the boring tool reaches the depth at which the workmen expect to
find coal, the operations are conducted with the greatest interest.
Every motion of the rod is carefully watched, and when the fragments
of rock or earth are brought to the surface, they are examined with
great care. When the coal is discovered there is much rejoicing, as
it is then certain that the prize has been gained. It is the same
in boring for coal as for oil. When a man in Western Pennsylvania
has “struck oil,” and, according to the local expression, “struck it
rich,” he feels that his fortune is made. More than one man has thus
raised himself above his fellows when his search for coal was rewarded
with success. An old story, which has been told many times, and will
bear telling a good many times more, is not inapplicable here.
[Sidenote: “DAD’S STRUCK ILE.”]
During the period of the first oil excitement in Pennsylvania, a
young man, whom the story represents to have been poor but honest,
was paying his attentions to a maiden of his neighborhood. The maiden
received his addresses, and the pair were engaged to be married. The
father of the damsel was an oil seeker, and one day his search for oil
was successful. That evening the young man visited his lady love. She
received him coldly. He asked the meaning of the coolness, and she
curtly replied, “I can’t marry you.”
“Why?” asked the young man, eagerly.
“Well,” said the girl, “I _can’t_ marry you; dad has struck ile.”
The young man went away sorrowing, for he had not great possessions.
As the story goes, the damsel, who had been thus suddenly lifted
from poverty to wealth in consequence of her father’s oil discovery,
remained unmarried for several months, but finally gave her hand to an
engaging stranger from New York, who dissipated the family fortune as
rapidly as it had been obtained.
[Sidenote: ACCIDENT AT CREUZOT.]
In 1853 some wealthy gentlemen sought for coal near Creuzot, in
France. The spot was carefully selected, and for four years the work
went on. The tools penetrated to a depth of more than three thousand
feet. This is probably one of the deepest borings ever made. An
unforeseen accident stopped the work at that point.