• A little history

    Almadén’s history is tied to cinnabar. Vestiges of human occupation in the area date to the Bronze Age (3500-2500 B.C.), where pictorial representations made from cinnabar’s red dust have been found within the caves and openings of the nearby mountain range. + information about cinnabar.

    In Roman times, a mine was built in the Sisapo region, with remains of roman villas being found in what is now the district os Almadén.

    The exploitation of cinnabar is thought to have commenced around the 2nd Century B.C., where it was primarily used as a colorant.

    After Roman times, mining activities declined until the arrival of the Arabs, who employed cinnabar and quicksilver in alchemy, encouraging the construction of the first metallurgy ovens, called xabecas or jabecas.

    During the Spanish Reconquista, these lands would fall under the control of the Orden de Calatrava, as part of its domains.

    It is thought that the Arabs continued exploiting the mines until 1135 AD, the year when King Alfonso VII conquered these territories. He proceeded to hand them over to the Templar knights, who, after suffering constant skirmishes from the Arabs, yielded all the Calatrava territory, including the mines, to King Sancho III.

    Mining activities and the commercialization of mercury were initially handled by the Orden de Calatrava itself, but were soon leased to private individuals.

    In the early 16th Century, Almadén was a small mining settlement comprised of the cinnabar deposit, several small distillation ovens, a small castle and a few houses. Mercury production was scarce and there had hardly been any developments in the uses of mercury with respect to those developed by the Arabs.

    In 1525, the mines of Almadén were loaned to the Fugger German banking family, due to a contract that considered the domains of the ‘Órdenes de Santiago, Calatrava y Alcántara’ as collateral for the monetary advancements provided by the Fuggers to finance the imperial election and wars of King Carlos V. The family would go on to govern this estate from Almagro, sending a representative to Almadén from 1525 to 1645 to manage the estate, residing at the Casa de los Fúcares.

    The discovery of the Americas in 1492, gave rise to an expansion period, as a consequence of the utilization of mercury in the amalgamation of gold and silver in the American mines.

    The town would grow, linked to the increased demand for production of this mineral. On one hand, it served as a place of residence for workers and on the other, with the establishment of new installations that serviced the mines, such as the first prison or Cárcel de forzados, named ‘La Crujía’, which was already operative in 1525, with an existing infirmary. It was replaced by a larger prison in 1754.

    The increase in the workforce and in epidemics caused by overcrowding in the town’s dwellings, with up to 4 or 5 families residing in a single hose, motivated the construction of the San Rafael Mining Hospital in the 18th Century, servicing the mines’ workers and their families.

    To help finance and maintain the hospital, superintendent D. Francisco Javier De Villegas, promoted the construction of a bullring with 24 houses on its outer ring, where these houses’ rents were destined to finance the hospital’s construction.

    In 1777, under the reign of King Carlos III, the Mining Academy was built, allowing the training of future foremen that would go on to improve the systems used for the mines’ exploitation.

    Exclusive mercury commercialization was conceded to the Rothschild Bank in 1835, lasting until 1921, where it would return to the Spanish Estate, until the mine’s permanent closure in 2003.

    In 2012, it was included as one of the places declared World Heritage of Mercury by UNESCO, alongside the Slovenian city of Idrija.

  • Mercury World Heritage

    Almadén and Idrija are two localities with mining exploitations that have shaped their culture, influenced their environment and inhabitants in multiple ways and instilled in their citizens a motivation to fight against destiny.

    Despite many infamous, terrible events taking place throughout the history of these sites, a considerable sense of belonging, closely influenced by the mining trade, has been acquired and transmitted along the centuries, from one generation to the next.

    The property includes the mining sites of Almadén (Spain), where mercury or quicksilver has been extracted since ancient times, and Idrija (Slovenia), where mercury was first found in 1490. The Spanish domain includes buildings related to its mining history, such as the Castillo de Retamar, religious buildings and traditional housing. Standing out at the Idrija site are the mercury storage facilities and infrastructures, as well as the miners’ houses and the mining theatre.

  • Why are we Heritage?

    To be included in the World Heritage List, the sites must have Outstading Universal Value and meet at least one out of ten UNESCO selection criteria.

    Cultural heritage refers to the monuments, building complexes, and places with a historic, aesthetic, archaeological, scientific, ethnological or anthropological value.

    Almadén and Idrija are clear examples of cultural, industrial, and geological heritage, with their cultures rooted in the respect of their history. Both sites are characterized by a high degree of integrity and authenticity, partly because of their communities’ awareness of their importance, strong roots and sense of belonging, backed by a strong cultural commitment.

    The geological anomalies that gave way to the largest mercury deposits and its later use in silver production, make the mines of Almadén and Idrija exceptional representations of human interaction with the environment.

    Almadén and Idrija differ in the type of mercury that is present in their respective deposits, with each of them being the most important type in its class. In Almadén’s case, it is overall, the largest deposit, while also featuring massive cinnabar. In Idrija’s case, one can find the largest share of native mercury (found in liquid form).

    The above-mentioned explains why both cities, having full awareness of the importance of their heritage, decided to prepare a joint nomination to the UNESCO World Heritage List.

    There are many similarities between the two mining complexes: the way in which the population responded to the difficult living conditions in the production of mercury and the technical and scientific response to the challenges faced.

    From the standpoint of mining engineering, both mining sites have set the standard of mercury mines throughout history thanks to the methods and techniques used within, making them distinct historical representations of this industry.

    Almadén and Idrija, including their mines and installations, are more than capable of demonstrating the scientific and technical evolution in the geological, mineralogical and metallurgical fields, as well as in civil and mechanical engineering for mining applications.

    Technological development is demonstrated not only in the mines, but also in the work carried out by miners, mining engineers and architects who contributed to shape the urban appearance of the towns, with emblematic and singular buildings, demonstrating the complete technical training possessed by the professionals at that time and their skilful use of materials, spaces and forms of application.

    Both mines complemented one another in the delivery of mercury around the world, which gave path to outstanding economic, social and cultural changes between Europe and America and driving the development of science and technology, as witnessed in the constant exchanges of know-how and equipment.

    In some cases, the intangible culture and craftwork (Idrija and Almadén lace, music, choir-singing and artistic manifestations) were largely the direct product of the work of the miners’ family members or tributes to their daily heroism and therefore, symbols.

  • History of the appellation

    Almadén has applied for the UNESCO World Heritage List on three occasions.

    The first time, it was presented under «The Mercury and Silver Binomial on the Intercontinental Camino Real» candidacy, alongside two other sites, the mines at San Luis Potosí (Mexico) and Idrija (Slovenia).
    The presentation took place in Seville in 2009, lying one point away from admission.

    The second application took place in Brasilia (Brazil) in 2010, once again falling short, due to several failures in small details of the San Luis Potosí (Mexico) project.

    Almadén and Idrija would once again apply for candidacy in Paris, in 2012, this time without San Luis de Potosí, after their express waiver. This candidacy would be presented with the name «Heritage of Mercury. Almadén and Idrija».

    On the 30th June 2012, in Saint Petersburg, UNESCO recognized its historical importance, making Almadén the third city in Castilla La Mancha to hold this distinction.

    The Committee recognized its value as the largest mercury mine in the world and a unique example of the exploitation of this metal throughout the centuries.

  • Mercury and its uses

    Mercury is extracted from cinnabar, a sulphide mineral, with a composition of 85% mercury and 15% sulphur. It is a very heavy, resilient and opaque material found in an earthy form and is one of the main sources of mercury.

    It can be found in low temperature hydrothermal vein deposits and impregnation deposits surrounding porous rocks, as present in Almadén, which has been mentioned in the past, by Estrabón (1st Century B.C.) and by Plinio el Viejo (1st Century A.D.), as one of the main sources of this mineral and the only location where it has been mined continuously for over two thousand years.

    Cinnabar ore goes through a roasting and distillation process inside specially designed furnaces to produce liquid mercury.

    Mercury is a rare and unique metal. It is found in a liquid state at room temperature and has an extremely high density, with one litre weighing 13.6 kg. It has a metallic glow and becomes uniformly dilated when heated. It conducts both heat and electricity and is able to alloy with most minerals at room temperature.

    Owing to its physical and chemical properties, mercury has become an essential metal for science, technology, industry, medicine, culture and ordinary life from prehistoric to current times. Its importance has been ever-changing for centuries. It has gone from being considered a mystical and mysterious substance to an important raw material essential for rapid technological development.

    Dating to ancient times, mercury and mercury compounds have been used to prevent and to treat various cutaneous and venereal diseases, among others. It was also helpful in vaccine preservation and as an antiseptic for cuts and rashes.

    As a high density liquid, mercury was, for various centuries, essential to measure the pressure of gases and fluids. Due to its uniform thermal expansion it was suitable for thermometer production. The first photographs captured on glass plates were also made with mercury.

    Mercury is able to amalgamate with most metals. Amalgams in dental fillings are widely known, while tin-mercury amalgam enabled the development of large mirrors.

    Beginning in the 16th century, the process of amalgamation was discovered and large quantities of mercury were used to facilitate the extraction of gold and silver from American ores, contributing decisively to the world economy.

    A similar circumstance took place in the second half of the 20th century, where it began to be employed extensively in the chemical industry (plastic manufacturing), the war industry (explosive manufacturing), the electrical industry (lighting and batteries) and agriculture (aerosol manufacturing).

    It has also been used as a spaceship propeller.

    Due to its shine and capacity to reflect light, mercury was also used in special telescopes designed for space exploration.

  • Importance of mercury in the world economy

    In the mid-16th century, Spanish conquerors discovered rich deposits of silver and gold in South America. With the help of mercury, they extracted these precious metals from crushed ore.

    The amalgamation process was introduced by Bartolomé de Medina in 1555. The treatment of ores with mercury enabled the extraction of gold and silver in a simple and low-cost procedure.

    The following centuries saw enormous quantities of silver arriving to the European market, converted into minted coins, which enhanced trade and an industrial revolution, consequently helping the economy, culture and science to flourish. Mercury from Spain and Idrija also contributed to this progress. Over a third of the worldwide production of mercury was used in amalgamation to extract gold and silver. This subsequently led to an increase in demand for mercury, which accelerated mining activities and the spread of mercury mines throughout Europe.

    Mercury compounds also co-created technological progress and changed the image of the world. However, because of their toxicity, durability, explosivity and other characteristics, they have also drawn attention to the hazards caused by their uncontrolled use.

  • The mercury cycle in the environment

    Mercury is naturally present in the environment and is part of nature’s cycle. It reaches the earth’s atmosphere by means of volcanic eruptions, industrial emissions and other human activities and then falls to the surface through rainfall, where it can accumulate or travel along surface water until it reaches the ocean. It is built up inside living organisms, thus entering the food chain. Elemental mercury is primarily inhaled into the human body. Organic mercury compounds are especially hazardous to human health, as any contact with them can cause severe diseases. Long term exposure to mercury and its compounds, even at low concentrations, has a detrimental effect on the central nervous system.

    Due to its toxicity and extensive use, mercury has become dangerous for human health and the environment. In the 1950s, widespread methylmercury poisonings occurred in Minamata Bay (Japan), caused by the release of industrial wastewater from a chemical plant. The realisation of mercury’s excessive burden on the environment and its harmful consequences led to its abandonment and prohibition of its use inside the European Union.

    In 2005 the European Commission adopted the “Community Strategy concerning Mercury”, which aims at addressing mercury pollution. In this Strategy, the Commission presented several actions for reducing European and global mercury emissions and use, including a proposal to ban mercury exports from the EU by 2011. On the basis of this Strategy, the European Parliament and the Council of the European Union adopted in 2008 a Regulation that bans exports of metallic mercury and certain mercury compounds and mixtures and the safe storage of metallic mercury. In 2017 this Regulation was amended, stipulating measures and conditions regarding the use, storage and trade of mercury, mercury compounds and mixtures, the production, use and trade of products with added mercury and the handling of wastes containing mercury, in order to guarantee a high standard of protection of human health and the environment against anthropogenic emissions and emissions of mercury and its compounds.

    On October 10th 2013, the United Nations Environment Program (UNEP) adopted, at a conference in the Japanese city of Kumamoto, the Minamata Convention on Mercury, which prohibits mercury use, production and trade.