Allchar deposit
Allchar (also Alsar Alsar Alshar or written ) is a gold - arsenic - antimony - thallium deposit in southern Macedonia. It was created under hydrothermal conditions at low temperatures. At times, the thallium- rich part of the deposit in the mine Crven Dol was dismantled. It is estimated that the ore still containing about 500 tons of thallium. The mineral Lorandite from this ore is used to study the solar neutrino flux.
Geology
The deposit is a gold deposits of the Carlin - type, similar to that of Carlin unconformity in the U.S. state of Nevada. The ore is a finely divided Au -As- Sb -Tl -Hg mineralization, which are embedded in carbonate rocks from the Triassic and volcanic tuff and dolomite rocks.
Mining
The mine Crven Dol was created in antimony- poor and arsenic and thallium- rich part of the deposit. Most of the ore consists of the minerals realgar, orpiment, arsenic-rich pyrite and marcasite.
Minerals
The main minerals of the ore are pyrite, stibnite, orpiment and realgar. The most important thallium mineral of the deposit is Lorandite, a thallium -arsenic sulfosalt with the composition TlAsS2. In addition, is Allchar locality numerous rare thallium minerals, nine minerals were discovered here also the first time. Type locality is Allchar for Bernhardit (Tl (As, Sb) 5S8 ), Dorallcharit ( (Tl, K) Fe3 3 (SO4 ) 2 ( OH ) 6), Jankovićit ( Tl5Sb9 (As, Sb) 4S22 ), Lorandite ( TlAsS2 ), Parapierrotit (Tl (Sb, As) 5S8 ), Picotpaulit ( TlFe2S3 ) Raguinit ( TlFeS2 ) Simonit ( TlHgAs3S6 ) and Vrbait ( Tl4Hg3Sb2As8S20 )
LOREX
The Lorandite Experiment ( LOREX ) used Lorandite from Allchar to detect the solar neutrino flux. This mineral contains large quantities of thallium isotope 205Tl, which is able to Neutrinoeinfang, producing the lead isotope 205Pb. This 205Tl ( νe, e-) 205 process has a relatively low threshold energy of 52 keV and a relatively high efficiency. With an age of the deposit from 4.5 to 4.2 million years of the solar neutrino flux can be determined over the last four million years, if it is possible to determine the content of 205Pb in a Lorandite sample. This reaction can be induced not only by neutrinos, but also by high-energy cosmic particles, but which have different penetration depths in the earth's crust. This made it possible to obtain reliable data by measurements at various depths of the deposit.