COPPER MINES.
Copper (from cuprum, a corruption of cuprium, from the island of Cyprus, whence it was formerly brought) was known at a very remote period; and in the early ages of the world, before iron was extensively in use, was the chief ingredient in domestic utensils and instruments of war. It is abundant; and is found both native and in many ores, the most important of which are the varieties of pyrites, which are sulphurets of copper and iron. The genus copper includes some thirteen species, and each of these contains several varieties.
The purest copper obtained in Europe, is the produce of the mines of the Swedish province of Dalecarlia. The following is a brief description of the principal of these immense and gloomy caverns, all of which boast a high antiquity.
The traveler’s curiosity is first attracted by the hydraulic machines which convey the water to the different quarters, and the power of which is such, that one of the wheels has a diameter of not less than forty-four feet. Another wheel, of proportionate magnitude, is employed to raise the ore from the mine to the surface of the earth, and is admirably constructed. Regular circles are placed on each side, and round these the chain rises, taking a larger or smaller circumference, in proportion to the necessary circle to be made, so as to counterbalance the weight, and consequently the increased motion of the bucket.
Exteriorly, a vast chasm of a tremendous depth presents itself to the view. This being the part of the mine which was first opened, either through the ignorance or neglect of those who had then the management of the works, the excavations so weakened the foundations of the hill, that the whole fell in, leaving a most chaotic scene of precipitated rocks, and a gaping gulf resembling the mouth of a volcano. Great care has been since taken that no such disaster should again occur. Plans and sections are drawn of all the galleries, &c.; and where the prosecution of the works in the same direction might be dangerous, orders are issued for the miners to stop, and an iron crown is fixed on the spot, as a prohibition ever to proceed further. The workmen then explore in a different direction, while every subterraneous excavation is nicely watched.
The traveler passes into the great chasm by a range of wooden steps, which cross, in a variety of directions, the rough masses of fallen rocks, of gravel, and of the ancient machinery. Ere he reaches the entrance of the cavern, he has to descend nearly two hundred feet, and this being accomplished, proceeds horizontally to a considerable distance within. He now loses the pure air of day, and gradually breathes an oppressive vapor, which rolls toward him, in volumes, from the mouths of a hundred caves leading into the main passage. He now feels as if he were inhaling the atmosphere of Tartarus. The Swedish iron mines which have been described, are mere purgatories when compared with this satanic dwelling. The descent is performed entirely by steps laid in the winding rock; and, in following the subterraneous declivity, the traveler reaches the tremendous depths of these truly Stygian dominions.
The pestilential vapors which environ him with increasing clouds, and the style of the entrance, remind him of Virgil’s description of the descent of Eneas to the infernal regions. Here are to be seen the same caverned portico, the rocky, rough descent, and the steaming sulphur, with all the deadly stenches of Avernus. The wretched inmates of this gloomy cavern, appear to him like so many specters, as poetic fiction has described them: and he is induced by the length of the way, joined to the excessive heat and its suffocating quality, to fancy that he will be made to pay dearly for his curiosity. In one part the steam is so excessively hot, as to scorch at the distance of twelve paces, at the same time that the sulphureous smell is intolerable. Near this spot a volcanic fire broke out some years ago, in consequence of which strong walls were constructed, as barriers to its power, and several contiguous passages, which, had it spread, would have proved dangerous to the mine, closed up.
The visitor has now to traverse many long and winding galleries, as well as large vaulted caverns, where the workmen are dispersed on all sides, employed in hewing vast masses of the rock, and preparing other parts for explosion. Others wheel the brazen ore toward the black abyss, where the suspended buckets hang ready to draw it upward. From the effect of such violent exercise, combined with the heat, they are obliged to work almost naked. Their groups, occupations, and primitive appearance, scantily lighted by the trembling rays of torches, form a curious and interesting scene.
The depth of the mine being at least twelve hundred feet, a full hour is required to reach to the bottom. The mass of copper lies in the form of an inverted cone. Five hundred men are employed daily; but females are not admitted, on account of the deleterious quality of the vapors. This mine was anciently a state prison, in which criminals, slaves and prisoners of war toiled out their wretched existence. Near the bottom is a rocky saloon, furnished with benches. It is called the Hall of the Senate, on account of its having been the resting-place of several Swedish kings, who came, attended by the senators, to examine the works, and here took refreshments. It was in this mine that the immortal Gustavus Vasa, disguised as a peasant, labored for his bread, during a long concealment, after having been robbed by his guide; and his first adherents in the struggle which placed him on the throne, were from the miners and peasants of Dalecarlia.
In the year 1751, a very rich copper mine was wrought in the county of Wicklow, Ireland. From this mine ran a stream of blue-colored water, of so deleterious a nature as to destroy all the fish in the river Arklow, into which it flowed. One of the workmen, having left an iron shovel in this stream, found it some days after incrusted with copper. This led one of the proprietors of the mine to institute a set of experiments, from which he concluded that the blue water contained an acid holding copper in solution; that iron had a stronger affinity for the acid than copper; and that the consequence of this affinity was the precipitation of the copper, and the solution of the iron, when pieces of that metal were thrown into the blue water. These ideas induced the miners to dig several pits for the reception of this water, and to put bars of iron into them. The result was, that they obtained an abundance of copper, much purer and more valuable than that which they had procured from the ore itself by smelting.
On the island of Anglesea, near Dulas bay, on the north coast, is Parys mountain, which contains the most considerable quantity of copper ore perhaps ever known. The external aspect of the hill is extremely rude, and it is surrounded by enormous rocks of coarse white quartz. The ore is lodged in a basin, or hollow, and has on one side a small lake, over the waves of which, as over those of Avernus, fatal to the feathered tribe, it is said that birds are never known to pass. The effect of the mineral operations has been, that the whole of this tract has assumed a wild and savage appearance. Suffocating fumes of the burning heaps of copper arise in all parts, and extend their baneful influence for miles around. That the ore was worked in a very remote period, appears by vestiges of the ancient operations, which were carried on by trenching, and by heating the rocks intensely, when water was suddenly poured on them, so as to cause them to crack or scale. In the year 1768, after a long search, which was so little profitable that it was on the eve of being abandoned, a large body of copper ore was found; and this has ever since been worked to great advantage, still promising a vast supply. The water lodged in the bottom of the bed of ore, being strongly impregnated with the metal, is drawn up and distributed in pits, where the same process is employed as in the Wicklow mine. The copper thus procured differs little from native copper, and is very highly prized.
In the Parys mine, eight tuns of gunpowder are annually expended in blasting the rock. Nature has here been profuse in bestowing her mineral favors; for, above the copper ore, and not more than two feet beneath the soil, is a bed of yellowish greasy clay, from three to twelve feet in thickness, containing lead ore, from a tun of which metal, upward of fifty ounces of silver are generally obtained.
COPPER MINE IN CORNWALL.
The copper mines of Cornwall, a view of one of which is given in the cut, are very numerous, and several of them large and very rich in ore. It is remarkable that in various parts of this country the earth has produced such an exuberance of this metal, as to afford it in large massy lumps of malleable copper, several pieces of which are shown in very curious vegetable forms. The particular ore named mundic, found in the tin mines, was for many ages considered of no other use but to nourish that metal while in the mine. In the reign of Queen Elizabeth, a laudable curiosity tempted several private individuals to examine into its nature; but the design miscarried, and the mundic was thrown, as useless, into the old pits in which the rubbish was collected. However, about a century ago, this purpose was effected by degrees; and the copper extracted from the ore now produces, on an average, upward of twelve thousand tuns, valued at between four and five millions of dollars, annually, equaling in goodness the best Swedish copper, while the ore itself yields a proportionate quantity of lapis calaminaris, for the making of brass.
At Ecton hill, near the river Dove, in Derbyshire, a valuable copper mine was discovered some years ago, and has since been worked to great advantage. In its position, situation and inclination, it differs from any mine yet discovered in Europe, Asia, Africa or America; the wonderful mass of copper ore not running in regular veins or courses, but sinking perpendicularly down, widening and swelling out at the bottom in the form of a bell. The works are four hundred and fifty feet beneath the river Dove, it being the deepest mine in Great Britain. On the opposite side of Ecton hill is a valuable lead mine, the veins of which approach very nearly to the copper mine.
Copper is converted into brass by the agency of calamine, an oxyd of zinc. It occurs frequently in beds, and in some places exists in great abundance. The Mendip hills, in Somersetshire, were once celebrated for their mines of calamine, which are now in a great measure exhausted. It is dug out of the earth, and being broken into small pieces, is exposed to the action of a current of water, which washes away the light earthy matter, and leaves the calamine. The whole is then thrown into deep wooden vessels filled with water, and agitated for a considerable time. The galena sinks to the bottom, the calamine is deposited in the center, and the earthy matter lies on the surface. The calamine, thus separated from its impurities, is ground to powder, and becomes fit for use.
Hungary abounds in valuable ores and minerals, and is most celebrated for its vast copper works, at a town called Herrengrund, built on the summit of a mountain, and exclusively inhabited by miners. Here the process, noticed above, of apparently converting iron into copper, is pursued with great success, several hundred weight of iron being thus transmuted every year. The vitriol, with which the blue water is strongly impregnated, can not be strictly said to convert the iron into copper, but insinuates into it the copper particles with which it is saturated; and this seeming transmutation requires a fortnight or three weeks only: but if the iron be suffered to lie too long in this vitriolic solution, it becomes at length reduced to powder.
In Japan, copper is the most common of all the metals, and is considered as the finest and most malleable anywhere to be found. Much of this copper is not only of the purest quality, but is blended with a considerable proportion of gold, which the Japanese separate and refine. The whole is brought to Saccin, one of the five principal cities of Japan; and it is there purified, and cast into small cylinders, about a span and a half in length, and a finger’s breadth in thickness. Brass is there very scarce, and much dearer than copper, the calamine employed in making it being imported from Tonquin in flat cakes, and sold at a very high price.
In addition to the copper mines thus described, copper has, within a few years, been found in the richest abundance in the vicinity of Lake Superior. The existence of copper there, was, indeed, known as early as 1636; and the trace of these early discoveries was never entirely lost. But the first scientific researches were made in 1842, by Dr. Douglas Houghton, who was acting as geological surveyor for the state of Michigan. According to his report, native copper exists in two or three different deposits about Lake Superior, where it is found in the richest abundance, both in veins and in large masses in the native state. Dr. Jackson also states, that he has seen one of these masses, twenty feet long, nine feet wide, and from four to six inches in thickness, and weighing about twenty tuns. He adds, that in a single year, thirty-three men, of whom only twenty were properly miners, had taken out forty-three tuns of ore, yielding thirty tuns of pure copper. Among the masses of copper obtained from these mines as early as 1848, were four, the weights of which, respectively, were seven thousand and eighteen, seven thousand four hundred and eighty-four, seven thousand six hundred and seventy-eight, and fourteen thousand pounds. Since that date new openings have been made; new mining companies formed, and the products of the mines very greatly increased: and it may yet be, that these mines will prove some of the richest and most valuable of the world.