The historical mines of Almadén, which were actively functioning for over two millennia, produced a third of the world’s mercury — a total of 7,500,000 flasks (Hernández, 1995). After mining and metallurgical production ceased in 2003, the mines were turned into a museum. Efforts are currently underway to have the mines declared a World Heritage Site

Kindelán Echevarria, Paz

Mazadiego Martínez, Luis Felipe

Orche García, Enrique

Puche Riart, Octavio

English

Servicio de Coordinación de Bibliotecas de la Universidad Politécnica de Madrid

metallurgy
Introduction
The historical mines of Almadén, which were actively
functioning for over two millennia, produced a third of the
world’s mercury — a total of 7,500,000 flasks (Hernández,
1995). After mining and metallurgical production ceased
in 2003, the mines were turned into a museum. Efforts are
currently underway to have the mines declared a World
Heritage Site.
Almadén is situated in the southwestern part of the
province of Ciudad Real in Spain. A Roman roadway
passed by the Alcudia Valley, to the south of Almadén,
between the cities of Emérita Augusta (now Mérida) and
Cástulo (now Linares). Another roadway, a bit further to
the west, started in the Alcudia Valley and went via
Cordova to the centre of the Iberian Peninsula, with a
branch going to Almadén. This exceptionally well-net-
worked geographical location contributed to the discovery,
exploitation and commercialization of the extensive
resources at Almadén. Although these historic Roman
roadways are no longer in use and have been replaced by
modern roads, along many stretches they remain quite
well-preserved.
In geological terms, Almadén is situated in the central
area of the Iberian Peninsula, a part of the Central Zone of
the Hercynian mountain range. It is part of the Vertical
Folders Domain. However, in northern Spain, this area
abuts the Recumbent Folders Domain. The succession of
compact quartzite and soft slate beds found in this setting,
together with the vertical position of the layers, results in
a characteristic and spectacular
Appalachian landscape. Unique
minerals such as massive
cinnabars (extraordinary pieces of
crystallized mercury sulphide)
and barites with cinnabar inclu-
sions are found in abundance in
this region. The epigenetic miner-
alization of cinnabar and other
minerals (barytes, dolomites, etc.)
is associated with Hercynian
orogeny. An exceptional universal
geochemical anomaly has gener-
ated the deposit. 
Historical heritage
The first known use of the
resource was in making the min-
eral pigments that were used in
numerous prehistoric paintings. The name Almadén comes
from the Arabic word for mine. The Almadén mine was
described by the Arab geographer Al Idrisi of Ceuta in the
12th century. At that time, more than a thousand men
worked at the mine, which had already been excavated to
a depth of 420 metres. Centuries earlier, the Romans had
begun extracting cinnabar in this area after vermillion had
been successfully commercialized throughout the
Mediterranean. Pliny the Elder (AD 23-79) had described
the distillation of native mercury from cinnabar in mar-
mites. Lead, silver and copper were also obtained at the
mines of Quinto del Hierro and El Mesto, east of Almadén.
Although there were many other mines in Spain, the one at
Almadén was the largest and most extensively developed.
In the Middle Ages, alchemists were preoccupied with
concocting the philosopher’s stone — a magical substance
that could purportedly transmute base metals into gold.
Mercury was thought to be one of the basic reagents of
philosopher’s stone. Mercury was also an important ingre-
dient in many medieval medicines. The Swiss chemist and
doctor Theophrastus Bombastus von Hohenheim (1493-
1541), who was better known as Paracelsus, rejected tradi-
tional medical orthodoxy and successfully identified the
main symptoms of various illnesses such as goitre and
syphilis. To treat them, he used sulphur and various mer-
cury-based compounds. 
The importance of Almadén is evident from its role in
one of the defining events of Western civilization —
Christopher Columbus’ voyage to the
Indies. In The History of the Indies
(Book 1, Chapter LXV and LXVI),
Father Bartholomew de las Casas
(1474-1566) reports that Columbus,
before embarking on his journey to the
New World, had asked the Catholic
Monarchs Ferdinand and Isabella to
furnish him with the services of gold
panners and miners from Almadén
(Prieto, 1968). Between 1525 and
1645, under the reign of Charles I,
Almadén was controlled by the Fugger
family. Later, from 1835 to 1911, con-
trol of the mines was vested with the
Rothschild family.
With the discovery of  mercury
mines in Huancavelica in 1563, colonial
South America’s needs of mercury were
The historical mines of Almadén
By O. Puche Riart, L. F. Mazadiego Martínez, P. Kindelán Echevarría, Universidad Politécnica de Madrid, Madrid, Spain; and 
E. Orche García, Universidad de Vigo, Vigo, Spain
Cinnabar crystals, Mina Vieja de Almadén (Puche, 1989) 
September/October 2009 |  105
met by the Vice Royalty of
Peru. However, New Spain
(as Mexico was then called
by the Spanish), continued
to rely on the mercury 
supply from Almadén.
Quicksilver would be trans-
ported from Almadén to
Seville. Protected by war-
ships, a flotilla bearing mer-
cury and other goods
would leave from Seville
and sail to Veracruz,
Mexico. The cargo would
then head to Mexico City
and the rest of the territory
over the Royal Roadway. On the return trip, the ships
would carry silver ingots bearing the royal stamp.
Even in those early days, there was great cultural
exchange between South America and Europe. At the
beginning of the 16th century, a special type of mercury
furnace, called xabecas, was introduced to Almadén. 
In the xabecas furnaces, ceramics pots were filled 
with cinnabar, sealed with clay and heated from below.
These furnaces found their way to the Huancavelica mine
in 1598. 
Another such example was the use of gunpowder in
mining. First employed in 1626 in the town of Schemnitz
(now known as Banská S˘tiavnica in present-day Slovakia),
gunpowder reached Almadén in 1689; it was also used to
build the drainage gallery of the Our Lady of Bethlehem
adit at Huancavelica. Technology also flowed in the oppo-
site direction. Kilns invented in 1633 by the prospector
Lope Saavedra Barba in Peru were introduced at Almadén
in 1646 by Juan Alfonso de Bustamente.
For a very long time, the Spanish economy subsisted
on the mining of mercury and precious metals coming
from the Indies. To ensure its sustenance, the best
Spanish scientists were sent there to develop mining
activity. Examples of Spanish scientists who played
important roles as expatriates include Antonio Ulloa
(1716-1795), who mentioned the existence of platinum
in his work Historical Account of the Trip to Southern
America (1748); the Elhuyar brothers, Juan José (1754-
1796) and Fausto (1755-1833), who discovered tungsten
in 1783; and Andrés Manuel del Río (1764-1849), who
discovered vanadium  in 1801.
Another important Spanish scientist who travelled to
conduct research in America was Jerónimo Ayanz (1513-
1613), who in 1606 invented a steam pump for the extrac-
tion of water in  the Potosí mine. His invention was one
step ahead of the pumps that Thomas Savery invented in
1698 and Thomas Newcomen invented in 1712. All of
these pumps were the precursors of the steam engine that
Watt famously invented in 1768 (García Tapia, 1992). The
Watt pump itself was introduced in Almadén at the begin-
ning of the 19th century.
Almadén as a centre of teaching 
In the 18th century, Mexican silver mining was expand-
ing rapidly and there was a growing need for quicksilver to
extract silver through amalgamation. However, in 1755, a
major fire at the Almadén mines created serious supply
problems for the next two years. Several projects were
implemented in the area during that period to forestall the
labour migration. The Buitrones de Almadenejos enclosure
was raised, the San Rafael hospital for miners was built and
a hard labour prison camp was set up. Another venture
undertaken at that time was the search for new mineral
deposits. It resulted in the discovery of the Las Cuevas
(1774) and La Nueva Concepción (1779) deposits in the
Almadén region. The second half of the 18th century also
bore witness to the development most of Almadén’s mining
infrastructure and architectural heritage including the
hexagonal bullring (1752), the Mining Academy (c. 1785),
the door of King Carlos IV (1795) and the winch at San
Carlos, Almadenejos.
Also in the second half of the 18th century, German
miners were hired to restore Almadén’s mining works.
They introduced systematic mining using the compass, the
theodolite and other modern instruments. In addition,
they introduced the teaching of mining engineering, which
resulted in the founding of Almadén’s Mining Academy by
King Charles III in 1777, just a couple of years after the
foundation of a similar academy at Freiberg.
Between 1745 and 1747, there was an unsuccessful
attempt to create a School of Mines in Guatemala (López,
1983). In 1757, an Academy of Mines was created in Potosí
(Habashi, 2003), but it proved to be short-lived (Serrano,
1994). The Mining Academy of Almadén, being the first
Spanish school of mines, was significant enough to influ-
ence the reopening of the Mining Academy of Potosí in
1779) and the creation of the Royal Seminary of Mining in
Mexico  in 1792.
A fire at the Almadén
mines provided the impe-
tus for the introduction of
new methods of timbering
(in 1790) and extraction.
In the Larrañaga method
(c. 1804), large brick
arches were used instead of
wood to eliminate the pres-
ence of combustible mate-
rial. This technique would
be supplanted later on by
other methods such as cut-
and-fill (at Mina Vieja,
around 1914), open pit
mining (El Entredicho
metallurgy
106 |  CIM Magazine |  Vol. 4, No. 6
A drawing depicting the xabecas 
furnaces at Huancavelica, Peru
The door of Carlos IV (1795)
mine, 1978) and vertical crater retreat (Mina Vieja, 1981;
Las Cuevas mine, 1986).
Modern installations, machinery and technologies
deployed at Almadén contributed greatly to the develop-
ment of mines and mining in general. Idria furnaces
(1806), mine shaft extractions machines (about 1870),
Cermak Spirek furnaces (1905), compressed air (1914),
electrification (1918), workshops and compressor rooms
(1924), mercury stores (1941), San Joaquin’s shaft (1952),
Pacific-Herrshof furnaces (1954), and the structural
reform of San Theodor’s shaft (1962) were some of the
more influential developments at Almadén. Many of these
still exist and have shaped the cultural and technical land-
scape of the mining industry in this territory.
Other patrimonial values
In addition to its natural, archaeological, historical and
architectonic heritage, nonmaterial cultural heritage has
also been significant. The religiousness of  Almadén’s min-
ers remains an important spiritual force among the people.
The miners entrust their lives to the protection of the
Virgin Mary in the form of various local Madonnas like the
Virgin of Linarejos, the Virgin of the Caridad del Cobre,
the Virgin of Candelaria, etc. The most important
patroness of miners, the Virgin of Estrella de la Mina (or
Virgin of the Star of the Mine), continues to be present at
all opencast mines. Similarly, because of the association of
her legend with lightning,  Saint Barbara became the
patron saint of artillerymen, military engineers, miners
and others who work with explosives. Interestingly, the
patron saints of mineral extraction shafts were the
Germanic saints of Freiberg — Saint Joachim, Saint
Theodore and Saint Aquilinus. They were introduced by
German technicians who worked at Almadén during the
second half of the 18th century.
Almadén today
Until recently, neither the archaeological and industrial
heritage of Almadén nor its monumental architectonic pat-
rimony had received any recognition from Spain’s central
government or the region’s local authorities. In fact, impor-
tant parts of the Almadén heritage were destroyed in the
20th century, especially during the early years of Spanish
democracy. The hard labour prison camp was demolished
at the end of the 1960s to make room for the new School
of Mines. The winch at Vadeazogues mine was pulled
down to facilitate the opening of the El Entredicho mine.
Finally, at the beginning of the 1990s, the large gate of El
Pozo mine was destroyed to accommodate the widening of
the road from Cordova to Almadén.
Fortunately, by the 1980s, attempts to safeguard the
site’s mining heritage were underway. A mining historical
museum was founded in 1985. The Spanish Society for the
Defence of the Geological and Mining Heritage was consti-
tuted a decade later. The Society issued a comprehensive
list of monuments that it considered essential to conserve.
In 1999, the Fundación Almadén was established to com-
mence several restoration projects. Among its first tasks
was the restoration of the San Raphael mining hospital.
Using funds put up by the Spanish ministry of science and
education, the Foundation assembled a team of architects
in 2002 to guide the restoration work. CIM
metallurgy
Suggested Readings
García Tapía. N. (1992). Del dios del fuego a la máquina de vapor: la introducción de la
técnica industrial en Hispanoamérica. Valladolid : Ámbito, Instituto de Ingenieros Técnicos
de Espagña.
Habashi, F. (2003). School of Mines: The beginnings of mining and metallurgical educa-
tion. Quebec City: Métallurgie Extractive Québec.
Hernández, S. A. (1995). Las minas de Almadén. Madrid: Minas de Almadén y Arrayanes,
S.A (MAYASA).
López A. J. M. (1983). Los hermanos Elhuyar, descubridores del wolframio. 1782-1783.
Madrid: Fundación Gómez-Pardo.
Maffei, E. and Rúa de Figueroa, R. (1871). Apuntes para una biblioteca española de libros,
folletos y artículos impresos relativos al conocimiento y la explotación de las riquezas
minerales y à las ciencias auxiliares. Madrid: J. M. Lapuente
Nemitz, R. (1997) Santa Bárbara a través de los tiempos. Madrid: Encuentro Ediciones.
Prieto, C. (1968). La Minería en el Nuevo Mundo. Madrid: Revista de Occidente.
Puche Riart, O. (1989). Mecanismos estructurales del volcanismo paleozoico en la región
alcudiense. Unpublished doctoral dissertation, Universidad Politécnica de Madrid, Spain.
Serrano, C. (1994). Transferencia de tecnología y relaciones de intercambio. Caso de
estudio: la amalgamación y las escuelas de minería de la colonia. In S. Figueiroa & M.
Lopes (Eds.), Geological Sciences in Latin America — Scientific relations and exchanges
(pp 201-233). Campinas Brazil: Universidade Estadual de Campinas, Instituto de
Geociencias. 
September/October 2009 |  107
Originally published in CIM Magazine, September / October, 2009
Reprinted with the permission of CIM
www.cim.org


The historical mines of Almadén

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