Topicality of Retrospective Estimation of the Badran Mine

Abstract

Retrospection and evolution of ore-placer gold content of known Badran mine, located in Oymyakon region of the Eastern Yakutia are analyzed for a century. Placers with extraordinary heavy concentrated min- eral content were mined long before discovery of the deposit. Then, after several vain forecasts, Nadvigovaya zone with lenticular veins of mesothermal quartz was commercially evaluated. Revision provides a reason to believe that, high-grade ores of the deposit were regenerated due to overlay of Au-Ag mineralization. Speci- ficity and perspective of the eroded primary sources are identified according to detailed study of heavy concentrate sampling on water courses of the Badran ore-placer cluster. Mineral composition of alluvium consists of significant amount of brown ore (10-50%) and magnetite (up to 10%); scheelite, ilmenite, zircon, ru- tile, arsenopyrite, anatase, apatite, barite, garnet, hematite, leucoxene, muscovite, pyrite, sphene, tourmaline, chalcopyrite and spinel are represented by single grains. Besides, crystals and spheroids of electrum also occur, as well as fine native gold of higher fineness. It is noteworthy that barite and iron-containing minerals are present, representing consistent sequence of transformation and decomposition of pyrite during redox reactions. Processes of hypogene oxidation and decomposition of minerals by late epithermal solutions were repeated. Future of the Badran mine is seen in reassessment of structural-substantial features and construc- tion of geologic-genetic (positional) model of the deposit, considered as a standard of regenerated epithermal mineralization of Au and Ag.