Part 18

The composition of the mountain, being of volcanic creation, it is a crumbling conglomerate mass; and unless the galleries are substantially timbered, the chances of their falling in present an instant danger to the miners. The men who are employed in the work of clearing the ancient galleries and putting in new levels have had many narrow escapes from falling earth. The Spanish mining regulations impose a very high rate of compensation in the case of accidents which occur in the mines; and as a doctor, whose duty it is to report on all casualties to the Department of Mines at Madrid, is attached to every working property, mine owners are exceptionally careful for the safety of their employées. On one occasion, when the Spanish representative of the present proprietary was being conducted by the manager through some new workings, a huge piece of the country rock fell upon his guide. His head was very luckily protected by one of the hard pot hats which the underground hands always wear; and although this helmet was badly dented, it probably saved the wearer’s life. The visitor was naturally much concerned, but the manager accepted the mishap with smiling philosophy. “You see,” he remarked, “I am not meant to be an expense to the owners, just yet.”

The labour of fortifying all the drives, as the work advanced, rendered exploitation both slow and expensive, while not entirely eliminating the element of danger from the operations. It was at one time intended to cut the lode by driving an adit into the mountain at a level of 150 feet below the ancient workings; but as it was discovered that this adit would have had to be shored up and cemented like an electric railway tube, the proposal was abandoned as impracticable. Since then, the difficulty has been successfully overcome by the adoption of another policy.

The present leaseholders opened their negotiations for the purchase of the Huercal Mines on the strength of the mammoth dumps which from a number of assays made by different firms gave results varying from 5·71 per cent. to 10·40 per cent. of copper, 2·19 per cent. of nickel, and 3·13 per cent. of cobalt. It was argued that even if the mines were worked out, the dumps alone, if scientifically treated with modern machinery, would return a handsome profit. But very little exploration work was required to convince the Englishmen that so far from the property being exhausted of its mineral treasures, the bulk of the mineral had been little more than pecked at; and a more comprehensive system of development disclosed the fact that in _El Monte Minado_ they had acquired a copper-cobalt mine of extraordinary richness. The consistent and surprising richness of the dumps in carbonates and copper pyrites made it abundantly clear that if the Romans, with their primitive methods and appliances, had regarded this ore as unprofitable for treatment, they must have found still more valuable deposits to engage their attention. There could be no other excuse for regarding five per cent. copper ore as débris. For the first time since the Roman miners left their Bonanza, the old workings were now cleared and the mystery was solved. These ancient galleries, as will be seen from the illustrations, were not driven on any systematic plan, but simply followed the lodes blindly through all their twists and curves. The idea of going boldly through the mountain and sweeping all before them does not appear to have been considered practicable by the Romans; and, doubtless, the danger of excavating in the soft country rock on a large scale had also been taken into their calculations. As the workings were freed from the rubbish that choked every drive and level, further traces of cobalt and nickel were encountered, and copper in its many beautiful forms became more abundant, and of richer quality. In the Napoleon gallery the ore was assayed to yield from 17·17 per cent. to 78·69 per cent. of copper, and at the extreme end of it was found to be in the face of a three-foot lode, in which native copper was also discovered.

As I follow Señor José Perez, the mine manager, through the old Napoleon and Esperanza galleries, it is impossible to resist the contagious enthusiasm with which he describes and exhibits the property. Certainly there is excuse on every side for their eulogiums. The copper in the lodes is very plentiful, while in the hanging-wall of the lodes important veins of pink and black cobalt are frequently to be found, and at all points where work had been done abundance of ore has been exposed. I was shown a large caverture, the roof of which is supported by a single column of ore, which had been left for that purpose by the Roman excavators. The miners who were clearing the drives at first took this circular chamber to be a break in the lode; but it is really a cavern in the walls, and roof of which nearly every variety of copper ore is to be seen. The spectacle is strikingly beautiful, and to the geologist it presents a feature of unusual interest. I have examined many caverns in mines, but this particular example, which has been christened “The Cathedral,” far exceeds in natural beauty anything of the kind that I have ever seen.

A considerable amount of useful development had been accomplished by clearings and surface cuttings on both sides of the mountain, and these have been of the greatest importance in the adoption of the latest scheme for working the mine. In one clearing the outcrop had been stripped over about 1,100 feet, and by this means the copper and cobalt lode had been exposed for a distance of 70 feet, and similar work had been done on the opposite side of the hill. As the result of much anxious consideration and many discussions it was decided to undertake the opening up of the mines on a scale which, it is safe to presume, the Romans never dreamed of, viz., by removing the top of the hill to a depth of thirty feet, as one scalps an egg. The ancient workings, situated at a depth of 180 feet from the summit, having been located, and their dimensions ascertained, the over-burden, which had been found to be only 30 feet in thickness, will be removed, and from that point down to 180 feet, where the ancient galleries are situated, is a mass of copper, cobalt, and nickel ores that will be worked by the open-cutting process. A trench has been cut from the “Bárris” clearing connecting with the “Marin” clearing on the other side of the mountain, and four lines of rails have been constructed to work the ores, which are loaded up into the trucks and conveyed to the sides of the hill. No timbering is necessary, shafts and drives are done away with, and all risks to life are eliminated. The soft nature of the country rock renders the work, which in quartz would be an impossibility without the aid of dynamite, a simple pick-and-shovel business, and by this means the mountain is being gutted at the price of labour and cartage.

THE RIO RIMAL COPPER MINES.

The Rio Rimal Mines, in the province of Gerona, are situated close to the quaint old-world village of San Lorenzo, which stands, surrounded by its mediæval fortifications, at the foot of a high mountain. Far above it an ancient watch-tower still looks out over the wide expanse of plain and valley. It is broken and weather-beaten, but is otherwise as it was left by the old Moorish warriors who built it. Within a mile or two, on the east and west, are the comparatively modern fortified places of Figueras and Rosas. In the municipality of San Lorenzo, at the beginning of the last century, was a huge Government Arsenal and Smelting Works, where the metals won from the neighbouring mountains were cast into cannon, and made into shot and shell. Among the hills are still to be seen the remains of busy mining camps where hundreds of men were once engaged in working the mineral deposits. Before Napoleon’s all-conquering marshals marched across the frontier the Spanish Government blew up the arsenal, destroyed the smelting works, and concealed the entrance to the more important workings. Nothing remains to-day but a few melancholy ruins to show the extent of the former operations.

The Government factories were never re-constructed. The proximity to the border, and the exposed nature of the country, combined with the experience of the then recent events, rendered the situation too insecure for the purpose, and the arsenals of San Lorenzo were re-built on more powerfully-protected spots at Ferrol and Carthagena.

Even the massive stone bridge over the river Muga, which was blown up to impede the passage of the French troops, has never been rebuilt. The interesting point about all this is the fact that somewhere, close at hand in the hills, must exist the mineral deposits which fed the factories before the Peninsula War. The tunnels and workings have been very effectually concealed--by no means a difficult matter. A few barrels of gunpowder would have brought down hundreds of tons of rock and débris over the mouth of the shafts and galleries, and left no trace of human handiwork. But that these mines are still there, and waiting only to be re-discovered, is an indisputable fact.

The operations of the Spanish owners on the Rio Rimal property commenced, as modern engineering science counselled, near the bottom of the hill, and they put in their galleries and levels to tap at lower depth the richest portion of the reserves of copper. But work had only been in progress for about years when the Carlist war broke out. For seven years operations had to be suspended, and during the whole of that period the mine was abandoned. When the owners again turned their attention to the property, it was to find that many parts of their galleries had caved in, and the mine had become flooded. After a considerable interval, the worst parts of the galleries were repaired. The water was pumped out, the level and inclined shaft were cleared, and work was resumed. The price of copper in 1874 at Swansea was very low, and the method of inclined shaft workings being very costly, all hope of continuing to work the property at a profit was extinguished. For thirty years nothing was done at the mine. In 1898 an endeavour was made by the present owners to obtain possession of the mines, but it was not until January, 1902, that work was resumed on the property.

It was then decided that the most profitable course to be adopted was to concentrate all labour upon the work of repairing and unwatering the second level, and of driving a further level some ninety or 100 feet lower down the mountain side. This work was at once put in hand, and the north-west gallery was driven a distance of 185 feet on the line of the lode, cutting entirely through the same for the whole distance. In many places the lode is mineralised for a width of fifteen inches, the ore assaying thirty-three per cent. copper. In driving this gallery some splendid copper was obtained. Work on the level has in the meantime been progressing steadily, although the workmen experienced great difficulty on account of the hardness of the rock. At the beginning of this drive a very hard conglomerate was encountered, which resisted all tools. For a time the formation defied dynamite, and small progress was made until the sandstone ground was reached. Thereafter work became easier, and consequently more rapid.

The Buena Presa property, which adjoins the Rio Rimal Mine on the north, was subsequently acquired, thus increasing the original area by 141 acres. The Rio Rimal lode traverses the adjoining concession for a distance of about 2,100 feet. It is a strongly-defined masterly lode, and has every appearance of producing large quantities of mineral when developed. Judging from the outcrops, it resembles the Rio Rimal lode in every respect; and although no systematic work has been done upon it, the probability is that it will be found to be of equal value.

THE CORUNA COPPER MINES.

The Coruna Copper Company’s property, which covers an area of 2,540 acres--a tract of country more than six times as large as Hyde Park--is situated in the mining district of Santiago, and is connected with the railway, which is about eight miles distant, by a first-class road. The country in which the concession is situated, consists of a series of low rolling hills, and the character of the ore, so far as it has yet been explored by the prospecting operations, is very similar to that produced by the Rio Tinto and Tharsis Mines. It is a low grade copper ore, carrying on the average twenty-three per cent. of sulphur, and from two to three per cent. of copper. No attempt was made by the late owners to determine by a systematic series of borings the extent over which the mineral actually exists, or the depth and character of the ore; but the prospecting work already carried out by the English company, and the natural outcrops found at many points on the concession, place it, in the estimation of some mining experts, quite beyond doubt that the mass of mineral is one of the largest known, extending in one direction for over two miles, apparently without a break. This preliminary work has clearly proved the whole of the north-west quarter of the concession; and taking the outcrops into account, one-half of the whole ground is assumed to contain mineral. Three shafts and nine trenches are being sunk, and numerous outcrops have also been located on the concession. The original estimate of the quantity of mineral was 50,000,000 cubic metres, equal in round figures to 250,000,000 tons. The most recent assays indicate a mean of three per cent. copper in the ore. The prospecting work has in every instance proved the accuracy of original estimates as to the value of the property, as well as the correctness of the opinion, that a very large output could be obtained with practically none of the unproductive development work required in most mining enterprises. It was recommended that mining operations should be chiefly “open-cut,” and of the simplest character, the exceptionally favourable conditions under which the ore exists rendering operations an extremely easy and inexpensive matter. The property is being opened up on these lines, and it is considered there will be no difficulty in supplying the concentrating works with 1,000, 2,000, or even 3,000 tons per day, all obtained from open cutting.

TIN.--THE MINES OF BEARIZ.

Fortunately for the present proprietary of the Beariz Mines, the late owners possessed considerable technical knowledge; and if the property was not worked extensively by them, the work was prosecuted on right lines. They overhauled the Roman shafts and put in new galleries; and at a time when the standard price of metallic tin was £153 a ton the mine returned the owners a handsome profit. Some years ago, when the mines were reopened and actively exploited, a large number of hands were engaged; and although the ore had to be carted by road to Vigo, large profits were made. Gradually the price of tin dropped, and the profits shrank until operations could only be conducted at a loss. Then work was suspended. Since 1878 the Beariz Mines have remained idle, save for the persistence of the “Tributors,” who have continued to make a livelihood by washing alluvials.

The three leases that comprise the Beariz group are entitled the “Esperanza,” the “Federico,” and the “Elena,” and together they have an area of 450 English acres of tin-bearing ground. Since the mines were closed down, the railway has been constructed from the port of Vigo to within twenty miles of the property, and the roads between Beariz and the railroad are well made and in excellent repair. Señor S. J. Bárris, who was requested to inspect the properties and report upon them by the intending purchasers, spent several weeks at Beariz ascertaining the dimension of the lodes, estimating the extent and value of the alluvial, and making assays. He traced four distinct lodes on the “Federico” property, three on the “Esperanza,” and two on the “Elena,” and his tests proved that the whole of these nine lodes carried rich oxide of tin (cassiterite), averaging thirty per cent. of the mineral. “I am well aware,” he wrote, in communicating the results of his examination, “that the average will appear to be very high, but I would point out that this is a very exceptional property; in fact, I have inspected almost all the known tin properties in Spain, and I can say with confidence that, taking into consideration the numerous lodes and the very rich alluvial deposits, these Beariz Tin Mines are one of the richest, if not the richest, mining properties I have ever seen.”

Worked as a quartz mine, as it was worked by the Ancients, the owners possess in Beariz an asset of proved value, but the property is rendered the more valuable by the fact that the lodes represent only one portion of its assets. For, in addition to the quartz lodes, the greater portion of the 450 acres is composed of tin-bearing ground, almost every yard of which will pay to work. On one side of the hill a large number of boulders are present in the alluvial, which reduces its value; but the major portion of the area is exceptionally free from unbeatable material, and consists entirely of tiniferous deposits. Tin is found in the decomposed granite, which is so soft that it can be worked by pick and shovels. The upper alluvial is about five feet in thickness; but the depth of the granitic formation, which is very rich in tin, has not yet been ascertained. It was for this reason that Señor Alfred Lasala, the leading mining engineer of Orense, reported that it is almost impossible to cubicate the quantity of tin ore in these concessions; but he added in his report that “in every shaft and every trench, cutting, or outcrop, from the highest point down to the bed of the river Beariz, which runs at a great depth below the workings, the tin ore is found in remarkable abundance.” Señor Lasala describes the formation of the Beariz tin deposit as tiniferous granite, concentrated in great masses of tin mineral, which is intersected by cross lodes of tiniferous, quartz veins, or stringers, containing the metal in great quantity. Two samples of earth, that had been washed to remove the mica, tourmaline, and other principal elements of crystalline formation that are present in the ore, assayed 62 per cent. and 81 per cent. of tin respectively; and Señor Bárris estimates that every ton of tin ore, after being properly concentrated, will assay from 62 to 65 per cent. black tin.

The upper alluvials contain a smaller percentage of tin than is found in the lower strata, a fact which is explained by the laws of specific gravity, and by the attention that has been devoted to the surface ground in times past. The granitic formation, which is practically virgin ground, is computed to be hundreds of feet in depth, and there is enough of it on the Beariz property to employ all the energies of the company for fifty years to come. The whole of this formation is traversed by innumerable veins of quartz, containing from 15 to 20 per cent. of tin, which will add enormously to the value of the output.

THE SPANISH TIN CORPORATION’S MINES.

The Spanish Tin Corporation, which was formed towards the end of 1901, became the purchasers of 1,361 acres of tin-bearing land in the Arnoya district of the province of Orense. The Government’s annual publication of Spanish mining statistics for the year 1900 gives the production of tin ore for the entire province at 240 tons, and adds, “So far, only one mine has been producing tin in the province, the ‘Roberto,’ which in nine month produced 240 tons.” The extent of the concessions, the richness of the immense tin-bearing alluvial deposits, and the exceptionally favourable conditions under which they can be worked, makes the property exceedingly valuable. The whole surface of the concessions is more or less covered with alluvial soil, with an average thickness of fully 3¼ feet of tin-bearing ground; and if one-half be deducted for boulders, surface soil and waste ground, the amount of block tin is computed at 30,368,365 lbs., and the value at nearly one million pounds sterling. Practically, it is said, the whole of this vast quantity of tin can be recovered by simple hydraulic working. In addition to the alluvial tin-bearing ground there has also to be taken into consideration the tin contained in the masses of decomposed granite lodes which traverse the property, and is estimated to contain 60,936,730 lbs. of black tin, of a value of nearly two million pounds.

THE PONTEVEDRA TIN MINES.

The revival of the mining industry has spread even to the province of Salamanca, where, according to the Government report, not a single mine had been worked during the year 1900. A reference is made, however, to visits of mining experts to the districts of Valsalabroso, but nothing is reported as to the result of their inspections. One result, however, was the acquisition of three properties known as San Antonio, Adela and San Pablo, having a total area of 437 acres of tin-bearing ground, on behalf of English capitalists. Three well-defined lodes have been discovered, and the leases have been specially pegged out to contain these lodes for a length of 2,500 metres, or about 2,700 yards. Apart from these lodes, it is stated that the whole of the ground is sufficiently rich to allow of the alluvial being profitably worked. Various tests have been made which endorse this view by giving a return of nineteen pounds of alluvial tin per cubic yard. The company, which has been formed in London to work the property, has decided to exploit the alluvial, while development work is being prosecuted on the lodes. Special tin-washing machines have been sent to the Pontevedra Mines, and they are now at work and producing tin. Labour is cheap and plentiful, and transport facilities are very favourable to economic working, while another important feature is supplied in the close proximity of a stream, which gives an abundant supply of water for all mining purposes.

THE PARAMO GOLD MINES.

I visited at Paramo, in the province of Léon, an alluvial gold-mining property, which appeared to possess all the natural advantages for economical and highly profitable working. This concession consists of an immense bank of alluvial, over 300 feet in height, and a great plateau, which has been proved to carry gold wherever tested. The richness of this plain was evidently fully appreciated in ancient times, and the remains of gigantic operations can be clearly traced. Water had been brought in from a great distance by canals; and at the western extremity of the plain, where it ends suddenly in steep bluffs, two

great valleys have been sluiced away. The water channels employed for this purpose are still visible, and are now used as country roads. Millions of tons of earth must have been washed here, and with satisfactory results, even with the imperfect appliances then in use, or otherwise work on such a gigantic scale would never have been carried out. On the lower ground, very extensive sluicing operations had also been carried on in ancient times, and a water-race has been brought from some three miles away. This water-race could be repaired at little cost, and sluicing be begun here on a large scale with a very small expenditure compared with what is usually necessary in such operations. Along the river, on both sides, are level stretches of alluvial, formed by the eating away of the higher ground by winter floods, and these deposits carry gold from the grass-roots down.

THE KINGSTON GOLD MINES.