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Charcas, San Luis Potosi, Mexico

It is amazing to think that thousands of years ago, in prehistoric times, enormous animals such as mammoths and mastodons, roamed the municipality of Charcas. Proof of this however is the discovery of fossil remains that are exhibited in the Casa de Cultura (House of Culture) in San Luis Potosí. Since these ancient times, geological and volcanic elements have been forming what is today an important mining locality.

Charcas, located in the state of San Luis Potosí, possesses certain geological characteristics that make it an area rich in minerals and oil. On one side of the southeast part of the state is La Llanura Costera, the Coastal Plain, characterized by elastic sedimentary rocks of marine origin. On the other side is the Sierra Madre Oriental whose rocks are much older, made up with shale, from the Upper Cretacious Period. In the flat plains of the region, perforated in the tertiary rocks of the region, are the oldest oil wells of the Mexican Republic. One such oil field, el Limon (Lemon) is located in the municipality of Ebáno. In the occidental region of San Luis Potosí, between the east and west ranges of the Sierra Madre are numerous volcanic systems and igneous rocks where there are many different mineral deposits. The area has bodies of minerals of both RELLENO DE FISURAS and REEMPLAZAMIENTOS, mainly sulphides of silver, lead, copper and zinc. The most important of these deposits is found in the mining area of Charcas.

The principal mine was given the name San Cristobal, in memory of Oñate’s father, Don Cristobal de Oñate. It was totally devastated by fierce natives and had to be re built in 1582 by the conquerors and missionaries.
The first operations began in 1583 in the Leones and the Santa Isabel mines. The rises and falls in the economy of Charcas was closely related to the conflicts which occurred in the area, some periods being very successful and others very troubled. In 1838, several unsuccessful attempts were made to modernize the mining of the region. It was not until 1862 with the aid of aviator companies, that work was re-established in the mines of San Joaquin El Alto, Santa Rosa and La Vascongada. It is worthy of mention that an aerolite weighing 870 kilograms, known vulgarly as the Rock of Iron, was located in the local cemetery of the parish of Francisco de Charcas. No one knew when or how this celestial body appeared in the area, if it had actually fallen there from the sky or if it had been taken there from another site. It was considered to be the best specimen of its kind in all of Mexico, but during the French Intervention it was taken back to France, and so Mexico was robbed of this treasure.

In 1911, the National Metallurgical Company and the American Smelting and Refining Company acquired the mining rights of the company Minera Tiro General, which had been founded some years before. Then, in 1924 it changed hands once again to become the Conpañia Minera Asarco S.A., which built a concentrator that started operating in 1925. The town benefited greatly with the arrival of the telephone and electricity, the installation of which was paid for by the mining companies. Between 1965 and 1975, The American Smelting and Refining Company changed its name to the Grupo Industrial Minera Mexico S.A. de C.V. By 1985, the work of the mines increased with the construction of a grinding mill with a daily capacity of 2400 tons.
Since a long time ago this location has been famous for its beautiful specimens of danburite, with perfectly formed, milky coloured crystals of almost 30 centimetres in length. In level 14 of the mine Aurora some completely transparent crystals have been found which could be classified as gem quality. Datolite, which is rarely found as a separate mineral is abundant in the Charcas area, its green crystalline mantle covering vast expanses of rock. Also many spectacular specimens of quartz with extraordinary characteristics have been found, and are highly prized by collectors.

Charcas, SLP


DamburitaLuis Lyons photo