Anzob mining-beneficiation combined enterprise

ANZOB MINING-BENEFICIATION COMBINED ENTERPRISE is the mining enterprise for the extraction and beneficiation of the complex mercury-antimony ores of the Dzhizhikrut deposit. It is situated within the Leninabad province of the Tajik SSR, within the arduous mountainous region. The deposit has been discovered in 1940; it was explored in 1945-59; the industrial operation is performed since 1954; the reconstruction and expansion of the enterprise is performed since 1966. Anzob mining-beneficiation combined enterprise comprises the underground mine, beneficiation factory, and auxiliary workshops. The major industrial centre is the Zarafshan settlement of the urban type (since 1952).

Dzhizhikrut deposit is situated within the limits of the ore field of the same name, which is part of the Zeravshan-Hissar mercury-antimony belt; it is formed with carbonatic and terrigenous formations of the middle and upper Paleozoic, and is confined to the junction of the large ruptured faults, namely, the Sharnirnyi dip-slip fault and Regionalnyi dip-slip-thrust fault. The mineralization is localized within the stratum of the breccias (from 10-20 to 200 metres and more), which have formed themselves on the account of the crushing of the carbonatic rocks of the Upper Silurian - Lower Devonian, and has the multi-tiered character; the entire stratum is considered potentially ore-bearing. The geological structure of the deposit is complicated by the large quantity of the disjunctive faults of the various orders. There are allocated 5 industrial sites, namely, Osnovnoy, Nizhniy, Tsentralnyi, Levoberezhnyi, and Rudnyi Vykhod # 4; the largest part of all the industrial reserves is concentrated within the Tsentralnyi site.

The main ore minerals are antimonite and cinnabar; less often there may be found metacinnabarite. There are widely available pyrite, marcasite; less often there may be found realgar, orpiment, sphalerite, hematite. The oxidized forms of antimony are represented by valentinite, kermezite, stibiconite, cervantite. The degree of oxidation of antimony ores ranges from 5 to 70%, it is 20-25% on average, and is controlled by the manifestation of the youngest after-ore tectonics. The major components of the ores are antimony and mercury (100:1); thallium represents the greatest interest among the trace elements; there has been determined the existence of selenium and tellurium; the harmful admixture is arsenic. The non-metallic minerals are represented mainly by the quartz, calcite, and dolomite, which amount to the major part of the various types of the ore-bearing breccias.

There is used the level-chamber system of development with the breaking-out of the ore with the help of the deep boreholes and with preservation of the interchamber pillars (width is 8-12 metres). There are worked out during the first turn the chamber reserves, and during the second turn the reserves of the pillars. The extraction of the ore is up to 85% (should be 83% according to design). The total dilution is from 30 to 50%. There are scheduled the commissioning of the ore down-passes to the lower horizon, of the blind shaft with the length of 500 metres (for people and loads), of the conveyor delivery of the ore onto the surface to the factory. The beneficiation of the ores is by the flotation method, with the activation of the antimony minerals by the lead nitrate, and with the subsequent collective flotation of antimony and mercury. The scheme of the beneficiation includes two major and two control operations, and also three repeated cleaning of the coarse concentrate. The final product is the collective mercury-antimony concentrate. The combined enterprise has been awarded with the "Order of the Badge of Honour" (1970).