The Mines and its Wonders
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A few years ago the number of tin mines worked in Cornwall amounted to 139, and to 26 in Devonshire; and about 20,000 persons were employed in them.
Although the wages of the miners are much inferior to those of the pitmen in the northern coal-fields, yet they have advantages over their brethren, being exempted from many of the evils to which the northern miners are subjected. They have no fear of the fatal fire-damp or sudden explosions. Intellectually they are also superior, as they are mostly engaged in work requiring the exercise of mind. Their wages arise from contract, and depend greatly upon their skill and energy. They mostly have gardens, which they cultivate, and when near the coast they engage in the fisheries, thus increasing their incomes and varying their mode of life.
After leaving Redruth the travellers proceeded over the wildest and most desolate of moorlands, with blocks of stone scattered about, towards the wonderful Botallack Mine, on the Cornish coast. No mine in the world is so singularly placed. Descending to the shore below, on looking upwards, the view appeared fearfully grand. In one part was a powerful steam-engine, which had to be lowered almost 200 feet down the cliffs. Here tall chimneys, pouring out dense volumes of smoke, were seen perched on the ledges of a tremendous precipice. Here and there also were the huts of the miners, disputing the ground with the wild sea-birds, while ladders of great length scaled the rocks in all directions, enabling them to ascend and descend to their work. In some parts were paths up which sure-footed mules, with riders on their backs, were trotting briskly along, where few people unaccustomed to dizzy heights would have wished to venture even on foot.
As they had determined to visit the mine, they had to ascend to the top of the cliff and then once more to descend among the rugged rocks to a ledge about midway between the summit and the ocean, where a small building, occupied by the mining agent, marked the entrance. Hearing who they were, the agent at once undertook to guide them, and produced a couple of woollen mining dresses and two large felt hats.
Each person having fastened four or five candles to his button hole, while he carried another in his hand, they began to descend through a trap-like entrance, by a series of ladders, which although strong enough in reality had a very rickety feeling. On reaching the foot of one ladder, they were conducted to the top of another, on to which they had to step, and thus descending ladder after ladder and passing ledge after ledge, they at length reached the bottom of the pit, where the end of a pump was seen drawing up the water from all parts of the mine.
They then commenced their progress along one of the numberless galleries, which was so narrow that two persons could scarcely pass each other. Now having to step over rough stones and often close to the edges of fearful pits, now to bend low under masses of overhanging rock, and sometimes to find themselves crossing unknown abysses by shaky bridges of planks, while the damp air felt hot and sickly, making the candles burn dimly. Here miners were at work with pickaxes getting out the ore. Having thus gone over, through, and under all impediments, they were informed that they were 120 feet below the level of the sea vertically, and horizontally 480 feet below low-water mark. Boats might even then be passing over their heads. Human beings were working still lower down. On the roof, the strips of pure copper could be distinguished among the crevices of the rocks through which the salt water was seen percolating in an unpleasant abundance. In their eagerness to obtain the rich ore, the miners had worked upwards until they had got within five or six feet of the bottom of the ocean. There the metal was still clearly visible, but even the most hardy miners would scarcely have ventured on an attempt to win another grain from the rock overhead, lest the water should rush in and overwhelm them, and inundate the mine.
Passing into a gallery where no one was at work, the travellers listened in perfect silence, and could hear the low murmur of the ocean rolling above their heads.
“Oh, that is nothing now,” said their guide. “When a storm is raging, I have heard the sound of the pebbles, which some large wave has carried outwards, bounding and rolling over the rocky bottom. On standing beneath the base of the cliff, where not more than nine feet of rock intervened between the sea and my head, the heavy roll of the large boulders, the ceaseless grinding of the pebbles, the fierce thunder of the billows with the crackling and boiling as they rebounded, produced an uproar such as those who heard it can never forget.”
For many years a blind man worked in the Botallack Mine, and supported a large family by his labour. So complete was his recollection of every turning and winding, that he became a guide to his fellow-labourers, when by any accident their lights were extinguished. He being afterwards cruelly discharged, engaged himself as an attendant to some bricklayers. While thus employed, with a hod of mortar on his back, he fell from a platform and was killed.
There are several other mines similarly situated to that of the Botallack on the coast of Cornwall, where the works are carried far under the ocean. Among them are the Wheal Edward, the Levant, the Wheal Cock, and the Little Bounds. In the two latter, the miners have actually followed the ore upwards until the sea itself has been reached, but the openings formed were so small that they were able to exclude the water, by plugging them with wood and cement.
On returning from the mine, the travellers, having doffed their miners’ dresses, inspected the outward machinery employed in crushing the ore on the landing-place in the side of the cliff, and drawing it up the precipitous tram, which leads to the summit, where it is stamped and prepared for exportation. It is mostly carried to Swansea, which, in consequence of the abundance of fuel in the neighbourhood, owing to its nearness to the sea, to its canals and railroads, has, in the course of half-a-century, from a mere fishing village become a town containing fully 40,000 inhabitants.
The Cornish mines are not the only ones which run under the sea. On the Irish and some parts of the English coasts there are several coal mines which are worked beneath the ocean bed to a great distance.
Another remarkable mine, that of Huelwherry, existed for many years on the Cornish coast. A rocky spot at about 120 fathoms from the beach was left dry at low-water, on which small veins of tin ore were discovered crossing each other in every direction. Although the surface was covered for about ten months in the year, and had at spring-tides nineteen feet of water over it, while a heavy surf often broke on the shore, a poor miner, named Thomas Curtis, about a century ago determined to attempt winning the ore. The work could only be carried on during the short time the rock appeared above water. Three summers were spent in sinking the pump-shaft, which had every tide to be emptied of water.
A frame of boards, raised to a sufficient height above the spring-tides, and rendered water-tight by pitch and oakum, was placed above the mouth of the shaft. Its sides were supported by stout props in an inclined direction. At the top of this wooden construction, which was twenty feet in height, a platform of boards was secured, on which a windlass was placed. The water was now pumped out of the mine and the machinery set to work; but the sea penetrated through the fissures of the rock, and greatly added to the labour of the workmen, while during the winter months, on account of the swell, it was impossible to convey the tin ore to the beach. Notwithstanding all these difficulties, the persevering projector was rewarded by obtaining many thousand pounds worth of tin. At length, during a gale, an American vessel broke from her moorings, and demolished the machinery by striking against the stage, when the water rushing in filled the mine. An attempt has been made of late years to again work the mine with improved machinery, but the venture not proving profitable it has been abandoned.
The travellers also visited the curious Carclaze tin mine near the town of Saint Austell. It is a prodigious hollow or basin, nearly thirty fathoms in depth and a mile in circumference, and has the appearance of a natural crater rather than a hollow made by human hands.
The sides are almost perpendicular, and a few footpaths alone lead down amid the rocks to the bottom. In every direction are seen the hollows made by the miners of ancient days, the white colour of the granite veined with the darker metalliferous streaks, and the curious shape of the rocks formed by the streams flowing down its sides, give it a remarkably picturesque appearance.
The machinery used for crushing the rock is set in motion by these streams. On every side the men, women, and children employed on the works are seen moving about in all directions, like a busy colony of ants. The ore is obtained without much difficulty.
A tunnel has been formed at the bottom of the mine through which the waters flow after they have performed their task, which also carries away the crushed granite, while the heavier metalliferous substances are precipitated into the troughs. Neither engine-house nor chimneys such as are seen in other mines are visible, while every detail of the work is exposed to view – indeed, the huge basin has the appearance of a mine completely turned inside out.
There are two methods of smelting tin. By the most common, the ore, mixed with culm, is subjected to heat on the hearth of a reverberating furnace, when ordinary coal is employed. By the other method, the ore is fused in a blast furnace, when wood fuel or charcoal is used. The tin when smelted runs off from the furnace into an open receiver, from which it flows into a large vessel, where it is allowed to settle. After the scoriae have been skimmed off, the upper and purer portion of the mass is refined, and the lower part re-melted.
Chapter Five.
The Metals found in Mines
The chief object of the travellers was to inquire into the mode in which mines in different countries are worked, the causes of accidents, and the best method of preventing them. Their knowledge was superior to that which most of our readers are likely to possess, and it will be necessary, in order to understand their proceedings, to glance at the mining districts of the world, and to describe some of the principal mines among them.
No country possesses, within the same area, so large an amount of varied mineral wealth as Great Britain. Besides the seventeen coal districts of Great Britain, we find in Scotland numerous lead mines in the clay slate mountains on the borders of Lanarkshire and Dumfriesshire. In the north of England, with Alston Moor as the centre, along the borders of Northumberland, Cumberland, Westmoreland, and Durham, are extensive veins of lead. Cumberland, the north of Wales, and the Isle of Anglesey produce copper ore, as also mines of lead and magnesia, with many other metals, – zinc, arsenic, cobalt, and bismuth. Iron in large quantities is found in South Wales, South Staffordshire, and in the Scottish coal-fields, where the ironstone appears in abundance alternating with layers of coal and other strata, and is generally won from the same pit as that from which the coal is extracted.
Besides coal, Ireland contains mines of copper and lead, found in the slate and limestone ranges, contiguous to the sea coast. Crossing from thence to Spain, we arrive in a country rich in mines, though, owing to its distracted state, for many years greatly neglected. Here lead is found in large quantities in the mountain chains.
Quicksilver is abundant from extensive veins of cinnabar in the province of Mancha. In Galicia tin has been produced from very early times. Iron ore is very abundant, and silver mines, for many centuries abandoned, are now again being reworked. Gold was at one period discovered in large quantities, but is supposed to be almost exhausted.
The most important coal-field of France is round Étienne, near Lyons. Mining operations are also carried on in Brittany and the Vosges. Although possessing less mineral wealth than England, the French were far in advance of us in regard to the management of their mines. Germany possessed the chief school for scientific mining. Its principal metalliferous sites are the Hartz Mountains, on the borders of Hanover and Prussia, and the Erzgebirge or Ore Mountains, which separate Saxony from Bohemia. They yield silver, copper, lead, iron, tin, and cobalt.
The most prolific sites of the precious metals in Europe are possessed by Austria. The Styrian Alps furnish a vast amount of iron. The province of Carniola supplies quicksilver. Hungary and Transylvania, copper, lead, antimony, and iron. The most extensive works are found in the neighbourhood of the town of Cremnitz and Schemnitz. The veins in this region obtain the enormous dimensions of from 20 to 200 feet in width. The extensive forests of oak, pine, and beech which clothe the hills supply fuel for the numerous smelting works, while water, carefully collected into reservoirs, moves the required machinery. The whole of the drainage of the mines is collected in a receptacle 600 feet below the surface, from whence it is conveyed under a lofty mountain ridge by a magnificent gallery twelve miles in length.
Norway and Sweden possess extensive mines of iron and copper, as also silver. The latter country furnishes the best iron in the world, and it is much used in England for the manufacture of steel.
Passing eastward to Russia, we find the rich mines of the Ural Mountains, which divide Europe from Asia, and then on to the Altai chain on the southern frontier of Siberia, we meet with rich mines of gold and silver, and other valuable metals. On the European side of the Ural there is a deposit of copper sand-ore, extending over a district of 480 miles in length, by 280 in breadth. The mineral wealth of Asiatic Russia is far greater. It consists of copper ores; iron cropping out at the surface, gold and platinum. The Altai Mountains especially produce silver, and some gold, with lead and copper ores. The silver mines of this region were worked at a very early period, as is proved by the discovery of an excavation a thousand feet in length, from which a stone sphinx was dug up, corroborating a statement of Herodotus that the Scythians possessed mines of gold and silver, which, according to his account, were guarded by monsters and griffins. Baron Humboldt supposes that he referred to the bones of elephants, and other gigantic animals, discovered at the present day in the steppes between the Ural and Altai chains.
Crossing the Atlantic to America, we find vast quantities of the precious metals in the mountains of the Brazils and along the whole range of the Andes. In the province of Minasgeraes, gold is obtained from subterranean excavations, as also by washing the surface soil, when diamonds are also found. Auriferous deposits exist in the deep valleys among the mountains of Chili, and in Peru and Bolivia are immense veins of silver ore. High up on the Andes are the mines of Pasco and Potosi; while in the same region, quicksilver, copper, lead, tin, and other metals have been discovered. The copper mines being nearest the sea, are generally worked, the ore being sent to Swansea.
The lofty plateau of Mexico in North America has, from the first, been celebrated for its rich silver mines, of which there have altogether existed no less than three thousand, but the larger number of these have long been unworked. The gold mines of California and of Australia are too well known to require mention; but we must not forget the rock oil, concealed for ages in the North American continent. Both the United States and Canada now yield an abundant supply.
The number of metals discovered beneath the surface, including the metallic basis of the earth and alkalies, amounts to forty-two, but metals, commonly so-called, number only twenty-nine. These are platinum, gold, tungsten, mercury, lead, palladium, silver, bismuth, uranium, vanadium, copper, cadmium, cobalt, arsenic, nickel, iron, molybdenum, tin, zinc, antimony, tellurium, manganese, tatiaum, chromium, columbium, rhodium, iridium, osmium, cerium. Many of these, however, are so rare, that as yet they are of no practical use. Gold has been known from the earliest ages, and is found in scales, threads, grains, and rolled masses, or nuggets, which latter have been discovered in California and Australia weighing from twenty to thirty pounds, but the largest of all met with was in Asia, on the southern side of the Urals.
Large quantities of gold were discovered on a marshy plain which had been thoroughly turned over, when it was resolved to take down the buildings in which the gold was washed, and under the very corner of one of them a lump was found, weighing no less than ninety-six and a-half pounds troy, and valued at 4000 pounds. Gold has been found in Scotland, and in the county of Wicklow, Ireland, where about 10,000 pounds worth was picked up in the bed of a river by the inhabitants, before the Government became aware of its existence. Gold is so malleable that a single grain can be beaten out to form a gold leaf covering a surface of fifty-six square inches, and it is so ductile that the same quantity may be drawn into a wire 500 feet in length. Silver is found embedded in various rocks, where it occurs in veins, assuming arborescent or thread-like forms, and occasionally appearing in large masses. The largest mass found in Europe was brought from Kongsberg, in Norway, weighing upwards of 560 pounds, but another, won from the mines of Peru, was said to weigh 800 pounds. The celebrated mines of Potosi, 10,000 feet above the sea, were discovered in 1545 by an Indian who, when chasing a deer, laid hold of a shrub to assist in his ascent; it came up by the roots, to which he found attached a quantity of glittering particles, which he at once knew to be silver. Veins of silver have been discovered in England and Scotland, but generally mixed with lead.
Iron, the most useful of all metals, is found in large quantities in England, in many parts of Europe, and the United States. At one time Sussex was full of iron mines, the furnaces being fed with charcoal, until so extensive was the destruction of the woods and forests that the Government interfered, and placed restrictions on the consumption of the timber.
On the discovery of the present method of smelting with pit coal, the works, which at one time numbered 140 in Sussex alone, were abandoned, and hop-fields now cover the ground where furnaces once blazed.
Copper ranks next to iron in utility. In Cornwall there are upwards of 100 copper mines. It derives its name from the island of Cyprus, where it was first obtained by the Greeks. It is employed pure for numerous purposes, and is also mixed with other metals to form bell metal, speculum metal, for optical purposes, and German silver.
Lead occurs in veins most plentifully in mountain limestone districts, and usually contains some portion of silver. There are lead mines in various parts of England, as well as in Spain, Saxony, and in Bohemia, and some very rich lead mines have of late years been worked in the United States.
Tin is found in Cornwall in larger quantities than in any other part of the world. It is generally discovered in the alluvial soil of low grounds, where it is known as stream tin, because it has been washed by the agency of water from the rocks in which it was originally embedded mixed with sand and gravel. Tin is also found in the island of Banca, in the Indian Archipelago, in Bohemia and Saxony, Chili and Mexico.
Mercury is a rare metal. The richest mines are at Almaden, a small town of La Mancha, in Spain. It is also found in Austria, China, and Peru, and a few other places. It is sometimes found in globules, but it is generally procured from one of its ores, cinnabar, a sulphate of the metal, of a red colour, and indeed identical with the richly prepared paint vermilion. A thousand workmen are employed in the Spanish mines, above or under ground. It freezes at an exceedingly low temperature, and was found solid during midwinter by the traveller Pallas. Of the other metals, some used as medicines, or pigments, or to form alloys, we have not time now to speak.
Chapter Six.
Salt and Quicksilver Mines
The object of the travellers was not only to inspect coal mines, but to view the wonders of the subterranean world. It is impossible to do more than give a very brief account of the places they visited. They had found their way to the Carpathian Mountains, in order to visit the salt mines of Wieliczka, a small town to the south of Cracow. The valley in which the mine is situated is fruitful and picturesque. Descending by a staircase of thirty feet or so, through a bed of clay, they arrived at the commencement of the level galleries, which branch off in all directions. Overhead was a ceiling of solid salt, under foot a floor of salt, and on either side grey walls of salt, sparkling here and there with minute crystals. The guide led them on through a bewildering maze of galleries. Now they entered a grand hall, now descended by staircases to another series of vaulted chambers. On every side was solid salt, except where stout piers of hewn timber had been built up to support the roof, or wooden bridges had been thrown over some vast chasm. As they descended, the air became dry and agreeable, and the saline walls more pure and brilliant. One hall, 108 feet in length, resembled a Grecian theatre, the places where the blocks had been taken out in regular layers representing seats for the spectators. Here and there were gangs of workmen, some labouring at the solid floor, others trundling wheel-barrows full of cubes of salt.
Soon after entering, they reached the chapel of Saint Anthony, excavated in the times of the Byzantines, supported by columns, with altar, crucifix, and life-size statues of saints. They appeared, from being coated with smoke, to be of black marble, but Mark, putting his tongue to the nose of one of the saints, discovered it to be of salt. Many of the saints, however, were disappearing before the damp, which enters in that higher region from the upper world. The heads of some, and the limbs of others had already fallen.
The guide had come provided with some Bengal lights, one of which he kindled on the altar, bringing into light this strange temple; then, as the flame burnt out, the whole vanished as if by magic. Passing across a wooden bridge, resting on piers of salt, they entered a vast irregular vault in which were two obelisks of salt, to commemorate the visit of Francis the First and his empress. As they reached the floor, a boy ran along the bridge above with a burning Bengal light, which threw flashes of blue lustre on the obelisks, the scarred walls, the vast arches, the entrance to the deeper halls, and the lofty roof, fretted with the picks of the workmen. Another hall was entered, with cavernous tunnels at the farther end, passing through one of which, they embarked upon a lake in a heavy, square boat, and entered a gloomy passage, over the entrance to which was inscribed, in salt letters, “Good luck to you.” Midway in the tunnel the halls at either end were suddenly illuminated, and a crash, as of a hundred cannon bellowing through the vaults, shook the air in such a way that the boat had not ceased to tremble when they landed in the farther hall. The noise was produced by a single gun.
A tablet, on which was inscribed, “A hearty welcome,” greeted them on landing. At a depth of 450 feet their journey ceased, although they were but half-way to the bottom. About 1500 men are employed in the mines, who labour only six hours at a time, and live in the upper world. The blocks are first marked out on the surface by a series of grooves. One side is then deepened to the required thickness, and wedges being inserted under the block it is soon split off. This salt bed occupies a space of 9000 feet in length and 4000 in width, and consists of five successive stages, separated from each other by intervening strata of from 100 to 150 feet in thickness, and reaching to the depth of 1500 feet.
More than ten years ago a serious accident, which threatened the destruction of the mine, occurred. While boring, to obtain some potash salts, through an aquiferous stratum, a spring was tapped, which poured an immense quantity of water into the lower galleries. The inhabitants feared not only the ruin of the mine, but the falling in of their houses from the melting of the salt pillars; but fortunately the inundation was confined to the lower galleries, and a powerful steam-engine being set to work, the water was again pumped out, and the spring blocked up. However, so vast are the excavations that it would have taken many years to fill them.