Although it has often been exaggerated in assessing, in Spain, the richness of the subsoil, its potential in useful minerals does not yet correspond to its exploitation qualitatively, or even quantitatively, adequate. If Spain has so far been one of the major European exporters of minerals, especially metals, this must be related not so much to its exuberant production, but to the scarce use made of it by the country’s processing industries. With all this, the number of production concessions, that of workers and the global value of the mining-metallurgical industries have been growing in the last thirty years (regardless, of course, from the general crisis that is now going through), although with frequent disharmonies that cannot be explained without recognizing how a satisfactory degree of equilibrium has not yet been reached in the economic-political equipment of the Spanish industry. One of the reasons – however, not the only, nor perhaps the main one – is in the sharp contrast between the abundance of metallic minerals and the relative deficiency of fuels, the former fully justify the fame of wealth attributed to the subsoil of Spain. For both lead and copper, this country has long enjoyed European leadership. The lead, which is extracted mainly from the southern slope of the Sierra Morena, in the provinces of Jaén (approximately half of the production comes from the mines of Linares and La Carolina), Cordova (Peñarroya) and Murcia (Cartagena), 300 thousand tons of mineral the year: the surface of the cultivated perimeters is however at least thirty times less than that which can be cultivated. Almost all Spanish copper is collected in the province of Huelva (Tharsis, Río Tinto) : its production, from 1913 to today, has remained slightly fluctuating around 3-3½ million tons. yearly. Of these, however, only 500-700 thousand tons. represent pure mineral; the rest is made up of cupro-iron pyrites which in recent times have also been treated to obtain sulfur. Various for the lands that enclose them (from crystalline to tertiary) and well distributed are the iron deposits. The richest region is Biscay, which provides more than half of the total extracted; followed by Asturias (Santander), the provinces of Almería, Teruel, Huelva and Murcia. The annual production presents significant differences in height: in recent times it has always kept below 5 million tons, while at the beginning of the century more than 7 were obtained from the Basque mines alone. Spain is also among the strongest mercury producers (now, however, surpassed by Italy): cinnabar (20-30 thousand tons per year) is extracted for 9/10 from the famous mines of Almadén (Ciudad Real), considered the richest in the world. Good quantities of zinc ore give the provinces of Santander, Murcia, Guipúzcoa and Cordova (150-100 thousand tons per year); and the quantities of manganese (45 thousand tons in 1925; 113 thousand in 1900; the mines are all located in the province of Oviedo) and of silver (from 75 to 90 tons in recent years) are anything but negligible, not to mention that the main among the many cultivated or ascertained metallic minerals (tin, cobalt, nickel, antimony, bismuth, etc.).
According to clothingexpress.org, there are also quite a variety of non-metallic minerals; among these, however, more than sulfur (75-100 thousand tons per year), which is obtained, in addition to pyrites, from the sulphate deposits of the provinces of Teruel, Albacete, Murcia and Almería (22 thousand tons of finished product in 1931), the potassium minerals found in various places in Catalonia and Navarre deserve special attention. The quantity extracted increased from 251,000 to approximately 700,000 tons between 1931 and 1933.
In contrast to this abundance of raw materials, as has been said, there is the relative deficiency of fuels. But not that they are missing. The hard coal reserves are calculated at 5.5 billion tons, and essentially distributed in two basins. The richest, which finds its place in the Paleozoic deposits of the Asturian mountains (Oviedo), and alone provides two thirds of the Spanish production, continues, beyond the Cantabrian mountain range, in the Leonese region. Even better is the quality of the coals in the other basin, the Andalusian one (Bélmez, province of Córdoba), which also supplies more than half of the Spanish anthracite. Both this and lignite are quite common (León and Palencia for the former; Teruel, Zaragoza, Guadalajara, Santander, Catalonia and the Balearics for the latter). The overall production, which at the beginning of the century was already around 3 million tons. per year, it rose to over 7 in 1918, but dropped to 4.7 in 1922, to return to 7 in recent times. With all this Spain is forced to procure again fromi to 2 million tons. of coal per year, thus fueling a considerable stream of English ore imports.
The united table helps to form an idea of the trend of Spanish mining production over the last twenty years:
By comparing this with the other table which summarizes the data relating to the transformation of the most important of the extracted materials, it is possible to grasp some of the characteristics of the Spanish industry.
Metallurgy and iron and steel have made great progress in Spain over the last thirty years, having taken a decisive boost from the world war. However, their production only uses up a small part of the raw material available (typically the case of iron and lead), which is exported raw or semi-finished. The development of this branch of activity has however allowed to gradually reduce the tax that the country owed abroad, and heavy industry, which was previously exclusive to the Basque region, has been spreading in Galicia, in the Levant. (Valencia) and in Andalusia (Malaga). Metallurgical production reaches for iron (crude, alloys and steel) over 1.5 million tons. per year, against an export of 3.5 million tons. of brute ore.