The BiCoNi Formation is a hydrothermal lode formation, in which

bismuth Bismuth is a chemical element; it has symbol Bi and atomic number 83. It is a post-transition metal and one of the pnictogens, with chemical properties resembling its lighter group 15 siblings arsenic and antimony. Elemental bismuth occurs nat ...

cobalt Cobalt is a chemical element; it has Symbol (chemistry), symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. ...

nickel Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slo ...

and

uranium Uranium is a chemical element; it has chemical symbol, symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Ura ...

ores have coalesced. It occurs mainly in the

Ore Mountains The Ore Mountains (, or ; ) lie along the Czech–German border, separating the historical regions of Bohemia in the Czech Republic and Saxony in Germany. The highest peaks are the Klínovec in the Czech Republic (German: ''Keilberg'') at ab ...

and is the youngest formation in the hydrothermal sequence (polymetalliferous (kb) formation, iron-barite (eba) formation, precious brownspar (eb) formation, fluorite-barite (fba) formation, BiCoNi formation). Due to its combination with uranium, it is occasionally also called the bismuth-cobalt-nickel-uranium formation.

Genesis

The BiCoNi Formation emerged during the contact metamorphic restructuring of sedimentary

slate Slate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade, regional metamorphism. It is the finest-grained foliated metamorphic ro ...

in the course of Variscan granite intrusions during the Subhercynian-Austrian (''Austrisch'') cycle about 100–80 million years ago. It is the product of an intracrustal, epithermal paragenesis. It runs in quartz

lode In geology, a lode is a deposit of metalliferous ore that fills or is embedded in a fracture (or crack) in a rock formation or a vein of ore that is deposited or embedded between layers of rock. The current meaning (ore vein) dates from th ...

types as the primary ores or cobalt and nickel, which usually occur together with

arsenide In chemistry, an arsenide is a compound of arsenic with a less electronegative element or elements. Many metals form binary compounds containing arsenic, and these are called arsenides. They exist with many Stoichiometry, stoichiometries, and in t ...

s, native bismuth and

pitchblende Uraninite, also known as pitchblende, is a radioactive, uranium-rich mineral and ore with a chemical composition that is largely UO2 but because of oxidation typically contains variable proportions of U3O8. Radioactive decay of the urani ...

Use

The BiCoNi Formation has been intensively mined since the

Late Middle Ages The late Middle Ages or late medieval period was the Periodization, period of History of Europe, European history lasting from 1300 to 1500 AD. The late Middle Ages followed the High Middle Ages and preceded the onset of the early modern period ( ...

for bismuth, later cobalt and nickel, and, since the late 19th century, also for uranium. In the second half of the 20th century it was intensively mined by SDAG Wismut.

References

Literature

* * * *

External links

* * {{cite web, title=Die Arsenproblematik in Betrieben der ehemaligen SAG/SDAG Wismut, periodical=Kompass 5/6 2005, url=http://www.igf-bbg.de/adobe/1210.pdf, format=PDF, 174kB, accessdate=2014-02-26, last=H.-D. Bauer, G. Stoyke, date=2005, language=German