Irkutsk National Research Technical University (Irkutsk, Russia):

Fedotov P. K., Associate Professor, Doctor of Engineering Sciences, Associate Professor, fedotov@istu.edu
Fedotov K. V., Head of Chair, Doctor of Engineering Sciences, Professor, fedotov@istu.edu
Burdonov A. E., Associate Professor, Candidate of Engineering Sciences, slimbul@inbox.ru

TOMS Institute LLC «Technologies of mineral separation» (Irkutsk, Russia):

Senchenko A. E., CEO, senchenko@tomsgroup.ru

Industrial studies of low-sulfide ores of a gold deposit located in Chukotka have been analyzed. The main ore minerals of the deposit are arsenic pyrite, pyrite, galena, chalcopyrite, pyrrhotite, ilmenite and sphalerite. Gold is found in the form of fine dust (0.001 to 0.01 mm) to large gold grains (4.0–4.5 mm), and also in the form of large (30 mm) aggregates in arsenic pyrite. The ore also contains silver (up to 5 g/t). A rational analysis of ore, crushed to 0.1 mm, has demonstrated the availability of 76–90 % of free gold, of 9.7–21 % of gold in aggregates,up to 1.2 % of gold coated in films confined to iron carbonates and hydroxides, as well as 0.4–0.8 % and 0.6–0.8 % of gold confined in sulfides and silicates, respectively. Industrial studies of the ore of the deposit have been previously carried out by the such institutes as VNII-1, Irgiredmet, Central Research Institute of Geological Prospecting for Base and Precious Metals (TsNIGRI) and TOMS. It is noted in respective reports that the ore grindability index for the deposit is 1.75–2.2 relative to the reference ore of the Natalka deposit. According to TOMS, the Bond index for the deposit ore is Wi = 18.44 kW·h/short ton. All studies recommend the use of gravity and gravity-flotation ore recovery methods with subsequent cyanidation of respective gravity tailings or flotation concentrates. Depending on the characteristics of gold and its content in the ore, the total recovery into gravity concentrates ranges from 42 to 96.4 %; additional recovery of gold by flotation from gravity tailings varies between 3.0 and 49.8 %. The gold recovery values are 93.8 % for the gravity concentration method and are 4.1–4.8 % higher (97.9 to 98.6 %) for the gravity-flotation method. The concentrates obtained by flotation of gravity tailings were found to contain free amalgamable gold (up to 70 %). This indicates a loss of fine free gold during concentration in jigging machines and concentration tables. A significant share of this loss is due to the gravity concentrate scavenging stage and to the separation of the gold gravity concentrate. Considering the availability of fine gold in the ore and its gravity tailings, it is deemed most rational to recover the gold using the centrifugal technologies. Cyanidation of industrial products ofgold gravity concentrate recovery and of the flotation concentrate has confirmed the efficiency of this process and the low sorption activity of the ore. The recovery into the cyanidation solution is 94.3–99 %.

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