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.â€â€”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.
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 inthe 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.
ENTRANCE TO A COAL MINE.
ENTRANCE TO A COAL MINE.
DOWN IN A COAL MINE.
DOWN IN A COAL MINE.
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. CaptainSavery 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.
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.
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 longby 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 isbroken 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.
“DAD’S STRUCK ILE.â€
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.â€
“Why?†asked the young man, eagerly.
“Well,†said the girl, “Ican’tmarry you; dad has struck ile.â€
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.
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.
The bore-hole was less than an inch in diameter, and was made by means of a steel chisel fastened into wooden rods, which were screwed together. The boring tool one day became broken at the bottom of the hole. All kinds of grappling implements were lowered to take hold of it, but none of them succeeded. The chisel seemed to be firmly lodged at the bottom, and resisted every attempt to withdraw it. After six months of effort the work was abandoned. One of the parties interested offered to subscribe half a million francs to be given to any one who would invent an instrument that could withdraw the chisel.
Several days after the abandonment of the enterprise, the foreman of the work mounted the staging and made another effort to raise the broken tool. The whole power of the steam engine was exerted in pulling the ends of the rods, when suddenly the rope gave way. The man’s hand was caught and crushed between the rod and one of the planks through which it passed. He stood there and shouted to the man to saw off the rod in order to release him. Then holding the remains of the ruined hand in the uninjured one, he walked to Creuzot, three miles away, and without uttering a word of complaint, underwent amputation at the wrist.
TUBBING A SHAFT.
After the coal is discovered, whether through surface indications or by borings, the preliminary working begins bymeans of a shaft and levels. Generally the first step is to sink a shaft or pit. When the ground is soft, the pit must be walled with brick, stone, or timber, as fast as the descent is made. When the pit is sunk through limestone and sandstone, the progress is slow, but the walls sustain themselves, and do not require either masonry or timbering. A great inconvenience in sinking a shaft arises from springs and small streams of water. In many places where this inconvenience occurs, the shaft is fitted with a wooden lining, or tubbing, as it is called, which is made of thick staves somewhat resembling those of casks, the joints being carefully fitted, in order to keep out all water, and to withstand great pressure. Sometimes this tubbing is made of iron, wrought or cast. Where the ground is loose, or composed of sand and water, the tubbing is forced down from the top, or sinks by its own weight. When this tubbing consists of masonry, it is built in a circle at the surface, and as fast as the earth is removed the masonry sinks. A fresh circle is added at the surface, and thus the work goes on. It was in this way that Brunel constructed the shafts which formed the descent into the Thames Tunnel. Sometimes shafts are sunk under water, and in such case they are lowered in a perpendicular position until the ends strike the bottom, and then the water is pumped out. An ingenious apparatus raises the mud from the bottom, and a pump is kept at work to remove the water.
Sometimes, in sinking a shaft through quicksand, the water runs in faster than any ordinary mode of drainage will remove it. M. Triger, an ingenious Frenchman, invented a machine by which the water could be pumped out. The cylinders of iron were five or six feet in diameter, and he divided them into three compartments, as nearly air-tight as possible. He forced compressed air into the lower one, and enclosed the workman inside. The man was thus in a sort of diving-bell. The compressed air, being forced against the bottom of the shaft, prevented the great mass of water from filtering through the sand. The small quantity which filtered in was, by the force of the compressed air, driven through the sand pipecommunicating with the surface. “Imagine an army of mice,†the inventor graphically said to M. Simonin, “and a cat suddenly to make her appearance, and you would have the picture of water reaching the bottom of our shafts through a thousand holes in the ground, if the presence of the air is lowered, and returning suddenly to the surface as soon as the air recovers its tension.â€
The rubbish and running sands are removed in buckets by hand, or by means of a rope passing through a pulley. Trapdoors communicate from one stage to the other, by means of which the buckets are removed without any serious loss of the compressed air. Shafts may be sunk through quicksands in this way to a depth of eighty or one hundred feet without difficulty. The laborers who pass their time in the compressed air work as easily as in the open atmosphere. Some of them, however, cannot remain there long, especially if they have the drum of the ear very delicate, or are in the habit of drinking to excess. The pressure of air in the chambers rarely exceeds three or four atmospheres.
AN INGENIOUS APPARATUS.
This apparatus is frequently used for laying the foundation of bridges in the beds of rivers, where there are deep quicksands. The famous bridge of Kehl, near Strasbourg, was constructed in this way, and the engineers say that without some such apparatus the construction of the bridge would have been impossible.
If a shaft has been sunk and properly supported,—that is to say, timbered or walled,—it is generally divided into compartments. The shafts are generally from fifteen to twenty feet in diameter, and consequently there is plenty of space for dividing them. One of the compartments will serve for the tubs, cages, or buckets, in which the coal is raised. Another is for pumps to draw off the water, and sometimes where the miners go up and down by ladders a compartment is made especially for them.
LEGAL NECESSITIES.
In all cases one compartment in the shaft serves as an air-way or chimney, whether the draft is free or not. In some countries the law requires that there shall be more than oneshaft, or opening, to every mine, while in other countries no such law exists. Many of the owners of mines are abandoning the single shaft system, and gradually supplying their mines with more than one entrance. Many terrible accidents, accompanied by a great loss of life, might have been avoided had the mines been constructed with more than one entrance or shaft. A striking example of this is in the terrible calamity at Avondale, a few years ago. The most approved arrangement of shafts for a large mine where there is explosive gas, and where water is to be pumped, is to sink one shaft for the pumps, another for raising coals, and a third for ventilation. At the bottom of the third one a large furnace is always kept burning.
In some of the mines there may be half a dozen shafts. Those through which the coal is drawn are called the winding pits, those where the pumps are fitted are called pumping pits, those where the men go up and down, are called labor shafts, and those for the passage of air are known as air shafts.
In many mining regions there is a class of pits that have been abandoned in consequence of the coal beneath being worked out. Sometimes these pits are made use of for purposes of ventilation. Proper care is not always taken of these abandoned holes, and they form dangerous precipices, through which a careless person may easily fall and be killed. Strangers strolling in the vicinity of mines occasionally step into these shafts and disappear, to be seen no more alive.