Allchar

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Allchar
General information about the mine
Information about the mining company
Start of operation 1880
End of operation 1908
Funded raw materials
Degradation of Thallium, antimony, arsenic
Geographical location
Coordinates 41 ° 8 '54 "  N , 21 ° 57' 13"  E Coordinates: 41 ° 8 '54 "  N , 21 ° 57' 13"  E
Allchar (North Macedonia)
Allchar
Location Allchar
local community Kavadarci
Country North Macedonia

Allchar (also written as Alsar, Alšar or Alshar) is a gold - arsenic - antimony - thallium deposit in the south of North Macedonia . It was formed under hydrothermal conditions at low temperatures. At times, the thallium- rich part of the Crven Dol mine was mined. It is estimated that the ore still contains around 500 tons of thallium. The mineral Lorándite from this ore deposit is used to study the solar neutrino flux .

geology

The deposit is a Carlin-type gold occurrence similar to that of the Carlin Discordance in the US state of Nevada . The ore is a finely divided Au-As-Sb-Tl-Hg mineralization, which is embedded in carbonate rocks from the Triassic and volcanic tuff and dolomite rocks .

Mining

The Crven Dol mine was constructed in the antimony-poor and arsenic and thallium-rich part of the deposit. Most of the ore consists of the minerals realgar , auripigment , arsenic pyrite and marcasite .

Minerals

Lorandite and auripigment from Allchar

The most important minerals of the ore are pyrite, stibnite , auripigment and realgar. The most important thallium mineral in the deposit is lorándite , a thallium arsenic sulfosalt with the composition TlAsS 2 . Allchar is also the site of numerous rare thallium minerals, a total of nine minerals were also discovered here for the first time. Type locality is Allchar for Bernhardite (Tl (As, Sb) 5 S 8 ), Dorallcharite ((Tl, K) Fe 3+ 3 (SO 4 ) 2 (OH) 6 ), Jankovićite (Tl 5 Sb 9 (As, Sb) 4 S 22 ), lorandite (TlAsS 2 ), parapierrotite (Tl (Sb, As) 5 S 8 ), picotpaulite (TlFe 2 S 3 ), raguinite (TlFeS 2 ), simonite (TlHgAs 3 S 6 ) and vrbaite (Tl 4 Hg 3 Sb 2 As 8 S 20 )

LOREX

The Lorandite experiment (LOREX) uses Lorandite from Allchar to detect the solar neutrino flux . This mineral contains large amounts of the isotope of thallium 205 Tl, which is capable of capturing neutrinos, producing the isotope of lead 205 Pb. This 205 Tl (ν e , e - ) 205 process has a relatively low limit energy of 52  keV and a relatively high efficiency. With an age of the deposit of 4.5 to 4.2 million years, the solar neutrino flux can be determined over the last four million years, if it is possible to determine the content of 205 Pb in a Lorandite sample. This reaction can not only be induced by neutrinos, but also by high-energy cosmic particles, which, however, have different penetration depths into the earth's crust. This made it possible to obtain reliable data through measurements at different depths of the deposit.

Individual evidence

  1. ↑ a b M. Pavicevic: Lorandite from Allchar - A low energy solar neutrino dosimeter. In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 271, 1988, pp. 287-296, doi : 10.1016 / 0168-9002 (88) 90171-4 .
  2. ↑ a b K.M. Subotic, MK Pavicevic: Status of the LOREX: Geochemical 205 Tl solar neutrino experiment. In: AIP Conf. Proc. 1998, 455, pp. 912-915, doi : 10.1063 / 1.57378 .
  3. ^ AV Volkov, T. Serafimovski, NT Kochneva, IN Tomson, G. Tasev: The Alshar epithermal Au-As-Sb-Tl deposit, southern Macedonia. In: Geology of Ore Deposits. 48, 2006, pp. 175-192, doi : 10.1134 / S1075701506030020 .
  4. ↑ a b Allchar at mindat.org
  5. ↑ a b Lj. Cvetković, VA Boronikhin, MK Pavićević, D. Krajnović, I. Gržetić, E. Libowitzky, G. Giester, E. Tillmanns: Jankovićite, Tl 5 Sb 9 (As, Sb) 4 S 22 , a new TI-sulfosalt from Allchar, Macedonia. In: Mineralogy and Petrology. 53, 1995, pp. 125-131, doi : 10.1007 / BF01171951 .
  6. ↑ M. Pavicevic, A. Elgoresy: Crven Dol Tl deposit in Allchar: investigation Mineralogical, chemical composition of Tl minerals and genetic implications. In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 271, 1988, pp. 297-300, doi : 10.1016 / 0168-9002 (88) 90172-6 .
  7. ^ S. Jankovic: The Allchar Tl-As-Sb Deposit, Yugoslavia and its specific metallogenic features. In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 271, 1988, pp. 286-286, doi : 10.1016 / 0168-9002 (88) 90170-2 .