Chañarcillo is a town and mine in the Atacama Desert of

Copiapó Province Copiapó Province ( es, Provincia de Copiapó) is one of three provinces of the northern Chilean region of Atacama (III). Its capital is the city of Copiapó. Geography and demography According to the 2012 census by the National Statistics Instit ...

, Atacama Region,

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

, located near

Vallenar Vallenar is a city and commune in Atacama Region, Chile. It is the capital of the Huasco Province and is located in the valley of the Huasco River. Vallenar has 52,000 inhabitants. Its main activities are farming and mining. It was founded as San ...

and 60 km from

Copiapó Copiapó () is a city and commune in northern Chile, located about 65 kilometers east of the coastal town of Caldera. Founded on December 8, 1744, it is the capital of Copiapó Province and Atacama Region. Copiapó lies about 800 km north ...

. It is noted for its

silver mining Silver mining is the extraction of silver from minerals, starting with mining. Because silver is often found in intimate combination with other metals, its extraction requires elaborate technologies. In 2008, ca.25,900 metric tons were consumed ...

. The town grew up after the Chañarcillo silver mine was discovered on May 16, 1832, by

Juan Godoy Juan Godoy (1800 – 1842) was a Chilean farmer and miner who in 1832 discovered an outcrop (''reventón'') of silver south of Copiapó in Chañarcillo sparking the Chilean silver rush. Villalobos, Sergio; Silva, Osvaldo; Silva Fernando and Est ...

. This event sparkled the

Chilean silver rush Between 1830 and 1850 Chilean silver mining grew at an unprecedented pace which transformed mining into one of the country's principal sources of wealth. The rush caused rapid demographic, infrastructural, and economic expansion in the semi-arid ...

. Villalobos, Sergio; Silva, Osvaldo; Silva Fernando and Estelle, Patricio. Historia de Chile.

Editorial Universitaria Editorial Universitaria is Chilean university press based in Santiago. It was established in 1947 with funds from private people and from the University of Chile. During its existence, it has published the works of generations influential Chilean sc ...

1995. First Edition: 1974. p. 469-472. It grew in prominence in the second half of the nineteenth century and became important in the Atacama mining industry and one of the most important mines to the Chilean economy. It was connected by railway before 1862. Today the settlement is largely in ruins. The Chanarcillo District produced at least $100 million in silver before abandonment. This production from up to 20 mines was limited to a third of a square mile. From 1860 until 1885, 2,500,000 kg of silver was produced. Most production occurred before 1930 and since then until 1960, only minor amounts of silver was produced by removing pillars in mines or from the dump material. In 1870, 1570 miners worked in the Chañarcillo mines; however the mines were exhausted by 1874 and mining largely ended in 1888 after the mines were accidentally flooded.Cortés 2017, p. 23. Despite this, Chañarcillo was the most productive mining district in 19th century Chile.

Geology

Chanarcillo is on the south flank of a

dome A dome () is an architectural element similar to the hollow upper half of a sphere. There is significant overlap with the term cupola, which may also refer to a dome or a structure on top of a dome. The precise definition of a dome has been a m ...

, the Sierra de Chanarcillo, characterized by radial

fractures Fracture is the separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displa ...

and northwest

striking Strike may refer to: People *Strike (surname) Physical confrontation or removal *Strike (attack), attack with an inanimate object or a part of the human body intended to cause harm *Airstrike, military strike by air forces on either a suspected ...

faults. Silver

ore Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 April 2 ...

occurs in nearly vertical

veins Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated b ...

within these fractures and faults within interbedded

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

s and

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock cont ...

s. This ore zone is an oxidized and

supergene_(geology) In ore deposit geology, supergene processes or enrichment are those that occur relatively near the surface as opposed to deep hypogene processes. Supergene processes include the predominance of meteoric water circulation (i.e. water derived from pr ...

sulfide Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to chemical compounds lar ...

enriched rock. Oxidized ores occur above the

water table The water table is the upper surface of the zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water. It can also be simply explained as the depth below which the ground is saturated. T ...

and supergene sulfide enrichment below. In the oxidized zone, ore minerals include native silver and

argentite In mineralogy, argentite (from the Latin ''argentum'', silver) is cubic silver sulfide (Ag2S), which can only exist at temperatures above 173 °C, 177 °C or 179 °C. When it cools to ordinary temperatures it turns into its monocl ...

have been replaced by

cerargyrite Chlorargyrite is the mineral form of silver chloride (AgCl). Chlorargyrite occurs as a secondary mineral phase in the oxidation of silver mineral deposits. It crystallizes in the isometric - hexoctahedral crystal class. Typically massive to colum ...

, iodobromite, bromyrite, embolite,

iodyrite Iodyrite or iodargyrite is a natural mineral form of silver iodide. Related minerals are chlorargyrite and bromargyrite Bromyrite or bromargyrite is a natural mineral form of silver bromide found mainly in Mexico and Chile. Hardness is 1.5 to ...

. In the supergene sulfide enriched zone, ore minerals include pearceite,

proustite Proustite is a sulfosalt mineral consisting of silver sulfarsenide, Ag3 As S3, known also as light red silver or ruby silver ore, and an important source of the metal. It is closely allied to the corresponding sulfantimonide, pyrargyrite, from whi ...

tetrahedrite Tetrahedrite is a copper antimony sulfosalt mineral with formula: . It is the antimony endmember of the continuous solid solution series with arsenic-bearing tennantite. Pure endmembers of the series are seldom if ever seen in nature. Of the two, ...

polybasite Polybasite is a sulfosalt mineral of silver, copper, antimony and arsenic. Its chemical formula is . It forms black monoclinic crystals (thin, tabular, with six corners) which can show dark red internal reflections. It has a Mohs hardness of 2.5 ...

, and pyrargyrite. Magnificent groups of large crystals have been found at Chañarcillo, including

stephanite Stephanite is a silver antimony sulfosalt mineral with formula: Ag5 Sb S4. It is composed of 68.8% silver, and sometimes is of importance as an ore of this metal. History Under the name Schwarzerz it was mentioned by Georgius Agricola in 1546, an ...

chlorargyrite Chlorargyrite is the mineral form of silver chloride (AgCl). Chlorargyrite occurs as a secondary mineral phase in the oxidation of silver mineral deposits. It crystallizes in the isometric - hexoctahedral crystal class. Typically massive to colum ...

and

adamite Adamite is a zinc arsenate hydroxide mineral, Zn2 As O4O H. It is a mineral that typically occurs in the oxidized or weathered zone above zinc ore occurrences. Pure adamite is colorless, but usually it possess yellow color due to Fe compounds a ...

References

;Bibliography * Silver mines in Chile Populated places in Copiapó Province Mines in Atacama Region Underground mines in Chile Former mines in Chile {{Atacama-geo-stub

Geology

See also

References