LLC «LIMS» (St. Petersburg, Russia):

Podolyan E. I., First Category Geologist, Master of Geology, pei.polya@gmail.com
Shelukhina Yu. S., Leading Researcher, Candidate of Geological & Mineralogical Sciences, shelukhina@gmail.com
Borozdin A. P., General Director, Master of Geology, a.p.borozdin@gmail.com

St. Petersburg University (St. Petersburg, Russia):

Kotova I. K., Associate Professor, Candidate of Geological & Mineralogical Sciences, Associate Professor, kotova_i@mail.ru

The study covers the ores of the three gold-silver type deposits, namely, Lichkvaz-Tei (Armenia), Nevenrekan and Perevalnoe (Russia). These differ in both geological structure and ore localization conditions. Detailed mineralogical studies of these ores were conducted to establish their natural types. The material composition for the ore types, their structural and textural features, the mineral balance of valuable components, and the grain-size composition of their constituent minerals may be used to predict the processing properties of ores at early exploration stages. Along with the traditional approaches, the method of sample pre-classification by factor analysis based on geochemical associations of ore-forming elements was tested. This enabled the development of an algorithm for identifying certain types in each sample and, consequently, the preparation of composite samples for further mineralogical studies. With due account of the geochemical associations, four ore-geochemical types of ores were identified for the Lichkvaz-Tei deposit based on the statistical analysis. These are the gold-arsenide, gold-copper-base metal, copper-zinc, and gold-silver arsenide-antimonide-sulfide types. For all the objects studied, a general ore-mineral parageneses formation sequence has been established: the early pyrite type is replaced by arsenopyrite-pyrite and chalcopyrite-sphalerite types, then by intermediate gold-chalcopyrite-galena-fahlite silver-bearing and late gold-silver-sulfosaline-fahlite and marcasite types. A wide range of natural types of ores have been established, such as: pyrite-arsenopyrite, gold-arsenopyrite, gold-galena-sphalerite, chalcopyritesphalerite types for the Lichkvaz-Tei deposit; gold-pyrite-sulfosaline and oxidized gold-pyrite types for the Nevenrekan mineral occurrence; silver-fahlite-chalcopyrite-galena-sphalerite type for the Perevalnoe deposit. This diversity is due to the different quantitative ratios of ore-mineral parageneses in the composition of the ores.

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