The entrance of the twentieth century mining fever awakens in the province of Salamanca, with the g

The entrance of the twentieth century mining fever awakens in the province of Salamanca, with the granting of titles to mining iron in several towns in the province, including those granted in the term Navasfrías rational scc61 with names Aurea, Cecilia, Reality, Second, Sin Nombre. These mines, whose concessions had begun in other areas of the province, are awarded in Navasfrías in 1902. Holdings not held ever because even being arsenopyrite mineral present in these areas, it was of little importance to perform profitable work in the extraction of this mineral. In 1914 broke the first world war, which brings the increasing demand for minerals such as wolframite, scheelite, cassiterite and hydrocarbons such as paraffin etc., Being granted Navasfrías other titles in 1918, mine Dolores Cervantes, Violet, Santa Fe, The Independent, Metaldilla, My Child, Friendship, Whitey; rational scc61 but this time for the extraction of wolframite and cassiterite. Surveys on the Peninsula for finding wolframite, both in Spain and Portugal, has its beginnings in the late nineteenth century, carrying out small farms with minor amounts of ore, increasing the quantities obtained from 1903 holdings begin to have some importance especially rational scc61 in Portugal. In Navasfrías the first search, this time in the Sin Nombre start mine. The Spanish production in 1905 is 375 tonnes, rational scc61 1906-200, in 1912-150, in 1913-84, in 1914-511, 1915 -. 159 80% of this mineral is sold to England at low prices, because it is a poor tungstic acid content. Also tungsten obtained in the Portuguese mines in 1906 was 570 tons, en1912 - 1330, in 1913-800, in 1914-967, in 1915-1400, in 1916-1600, in 1917-1200, 60% of acid tungstic. The prices reaches this mineral during the First World War in a market controlled by the English, reaches not exceed 300 pounds per ton; making rational scc61 maximum prices of 7.82 pesetas Kg is shuffled, rational scc61 with a change in 1914 to 26.08 pesetas per pound. rational scc61 Tungsten, tungsten, or tungsten, symbol W, belong to the group 6 of the periodic table of elements, with atomic number 74. Its melting occurs from the 3410 C and the boiling when it reaches 5930 C, having the coefficient lower thermal expansion of any pure metal. For tungsten, the raw material is melted rational scc61 sodium carbonate, thereby obtaining sodium tungstate, sodium tungstate soluble, then extracted with hot water and treated with hydrochloric acid, thereby producing the tungstic acid. This compound once washed and dried form oxide WO3. The metal is obtained by reduction with hydrogen or carbon oxide at 1200 C. The resulting powder is pressed and sintered. The tungsten or tungsten, is mainly obtained from two elements, wolframite rational scc61 tungstate of iron and manganese, and scheelite, tungstate of calcium. In 1920, Navasfrías has 1693 inhabitants, 815 V and 844 F, more 111 missing, 72 V and 39 H, giving then also start operating the Salmantina mine, with interruptions in activity come about until 1975, taking place in its last stage leveraging dumps grinding and washing materials in mechanical tables also Rubiós materials next to river in which wolframite, tin and native gold are found washed. rational scc61 In 1930 he was granted the operation of the Teso of Slaughter. All operations rational scc61 remain open until after the middle of the 50s about the Salmantina except as discussed above, which together with Carrasquera Mine (The Filona), Mina Mina Deep and Bonita, would be the most productive. At this time Mina holdings Bilbao (Teso Pelao) and Mina Oria also take place.
Operations wolframite of Navasfrías Mining operations wolframite and cassiterite, together with minerals from Portugal upcoming holdings CELORICO, Guarda and Belmonte, attract more people to this town, opening a time, we could say, of plenty for Navasfrías citizens, with the highest population in the year 1950, with 2106 inhabitants, 1048 men and 1058 women, being the legal population 2159, and the census of missing 27 men and 26 women. Censuses until this time, since the beginning of the century, had been a steady increase, year inhabitants 1900-1459, 1910-1631, 1920-1698,1930-1694, and 1940-1880. Between 1920 and 1930, Navasfrías suffers stagnation rational scc61 in the population census, a decrease of 4 inhabitants due to the strong rational scc61 increase rational scc61 in the emission