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.
PARAMO.