Copper production in Russia.
Currently, the copper industry of Russia and other countries of the C.I.S. comprises more than 25 mines, 18 concentrators and ten smelters and refineries. Most Russian copper operations are located in the Urals, the exception being the Urup enterprise in the Krasnodar region.
Four broad categories of ore are mined and processed. The Dzhezkazgan No 1 and No 2 plants, and the Kafan and Turjin concentrators, treat copper-only ores; the Almalic and Balkash concentrators process copper-molybdenum ores; the Nickolsk (Dzhezkazgan No 3) complex processes copper/lead/zinc ore; while ten plants - Akhtal, Bashkir, Buribai, Gai, Kirovgrad, Krasnouralsk, Madneuli, Sredneuraslsk, Urup, and Uchali - treat copper/zinc ores. Copper concentrates are also produced as a by-product at a number of plants treating ores mined primarily for lead/zinc, wolfram/molybdenum and tin.
During the period 1985-93 a number of new plants were put into operation, namely Nickolsk, and a section of the Almalic concentrator, while refurbishing and reconstruction were carried out at the Kranouralsk and Bashkir plants. However, most of the concentrators were built in the 1930s and because of this a number of them are in poor condition, with obsolete equipment. Because of their age, and also in some cases a lack of ore, a number of concentrators have been shut down, namely Karabash, Pyshma, Akhtal and one section of the Sredneuralsk plant.
In recent years the ore reserve base of the Russian copper industry has suffered great change. A number of deposits have been depleted and geological and mining conditions generally have become more complicated. The typical depths of underground workings have increased to between 600 m and 1,000 m, the incidence of rockbursts has increased, and water influxes have become a serious problem. Mining and trasportation equipment is old and showing signs of wear, and there is a lack of application of new high-efficiency techniques. Added to this, there has been a lack of capital investment in developing new mines and processing plants in order to maintain productive capacity.
Many of the Urals deposits are depleted. Such open-pit mines as Lavrovo-Nickolayev, Volkovsky, Sibali, Uchali, Molodyozhny and the Gai group of pits are on the verge of closure, as are the underground mines Degtyar, Krasnogvardeisk, Lomovsk and Novo-Yezhovsky. Overall, their capacity is now only 70% of their capacity in 1990.
In the Urals region, mining capacity has decreased, mainly as a result of delays in the commissioning of new mines, with the result that the commissioning of new capacity lags far behind the depletion of existing reserves. As examples, development of the Uzelgin underground mine is proceeding only slowly, while the construction of the Sibai and Uchali underground mines is well behind schedule. The fall in Russian ore output, coupled with the cessation of supplies of copper concentrates from Mongolia, has resulted in a mis-match between mining, concentrating and smelting capacities.
In other countries of the C.I.S. the situation is the same. In Kazakhstan, for example, there is a problem with the feed for the Balkhash copper concentrator, because the high-grade Sajak ores have been depleted, while at Kounrad, to maintain tonnage, the ore cut-off grade has already been lowered to 0.3% Cu. At the Kamyshin open-pit mine of the Vostochno-Kazakhstan Copper Chemical Combinat, production is coming to an end.
Similarly, in Uzbekistan, mining of the Sary-Cheku deposit, which feeds the Almalic concentrator, is also coming to an end.
Changes in the state structure of the former USSR in 1991 led to reconsideration of the industry's perspectives and development of new deposits. Thus, in Russia, great attention is being paid to new deposits in Siberia, especially the Udokan deposit, which is now scheduled for early development although it was not previously planned to be brought into operation before the year 2010.
Likewise, in other countries of the CIS some new deposits will be put into operation earlier than previously planned. In Kazakhstan, for example, intensive design work is being undertaken for the Boschekul copper concentrator, which will process material from a complex copper/molybdenum oxidised/mixed sulphide porphyry type ore. Also in Kazakhstan, the large Aktogai copper/molybdenum porphyry deposit is being prepared for production and an open pit is being developed by the Vostochno-Kazakhstan Copper Chemical Combinat at the Shemonaikhinsky deposit, which is expected to have an operating life of 18 to 20 years.
In Uzbekistan the tonnage of the ore reserve base for the Almalic concentrator is being expanded by lowering the cut-off grade to 0.2% Cu. This will make it possible to work the mine without the need to strip any overburden and prolong the mine life for several decades.
Copper metal production
Refined copper metal production in Russia and the other countries of the C.I.S. is based mainly on domestic concentrate feed. In Russia the main copper producer is the Norilsk copper plant, which accounts for 45% of C.I.S. production. In Kazakhstan copper is produced at the Dzhezkazgan and Balkhash plants, the former accounting for 20% of C.I.S. output. In Uzbekistan copper metal is produced at the Almalic plant. All the above-mentioned plants produce blister copper and copper cathode, and all of them have acid production facilities. Any increase in C.I.S. copper production will require, in addition to the construction and commissioning of new facilities, the modernisation of existing operations.
As an example, at the Sredneuralsk copper smelter, the construction of the first stage of a new metallurgical shop is underway incorporating a new fluid-bed smelting technology developed by Professor Vanukov. Subsequently a second stage expansion of the plant will be undertaken, doubling the plant capacity and giving it the capability of efficiently treating concentrates from Uchali, Gai, Urup and Bashkir, together with copper-bearing concentrates from other sources including imported feed.
At the Almalic copper plant, a technology using oxygen flame smelting has been successfully introduced, the average copper recovery to blister copper being 96.8%. The wide range of products at Almalic include blister copper, high-quality cathode, copper wirebars, wire rods, precious metal ingots, selenium and tellurium as dusts, powders and slimes, and sulphuric acid.
One of the problems at existing copper operations is the treatment of waste materials. During the years of operation, significant volumes of copper bearing waste products have accumulated in dumps at all sites. These range from:
* Overburden dumps
* Dumps of (payable) oxidised copper ores
* Dumps of unpayable sulphide copper ores
* Tailings dumps
* Reverberatory smelting slags
* Oxygen flame smelting slags
* Pyrite and pyrrhotite products
In the Urals alone there are enormous volumes of accumulated waste products, including about 700 million |m.sup.3~ of overburden, about 200 Mt of tailings from concentration processes, and more than 95 Mt of slag. Significant quantities of S|O.sub.2~ are generated. The tailings dumps alone contain more than 1 Mt of copper, and the slag dumps hold as much again.
To date, only about 4% of the overburden rocks have been utilised, generally for backfilling in the mines. Otherwise, the main use made of overburden is in the construction industry as a building material.
So far, the well-known and widely used technologies of heap and bacteria leaching have been used in practice only as pilot-scale operations, treating Kalmakir, Kounrad and Degtiar ores. However, great interest is being shown in these technologies, with the possibilities they offer for the treament of old overburden dumps. Thus, at the Almalic Mining and Metallurgical Comkplex the waste dumps contain 16 Mt of material grading 0.8% Cu and commercial grades of precious metals, plus more than 60 Mt of "unpayable" material which could be considered as payable copper ore if the cut-off grade were lowered to 0.2% Cu.
A number of alternative technologies have been tested at the Complex, namely sulphuric acid leaching, sorption and extraction, and autoclave roasting. Considerable interest is being paid to the possible recovery of precious metals. The Complex is interested in long-term co-operation with third parties in the treatment of this material.
At present only 2% of the annual production of tailings is being utilised. However, in the near future, at the Sredneuralsk concentrator, it is planned to treat 1 Mt/y of old tailings to produce more than 60,000 t of pyrite concentrate and 300,000 t of quartz product.
Over all, only 3% of the annual output of the metallurgical slag produced is being used, although at the Norilsk Complex some 23% of slag are utilised, some for construction material and some for backfilling mines.
The utilisation of tailings and slag is part of a low-waste production concept, but at present the volumes of these resources exceed their utilisation volumes many times over. The minimisation of waste and the introduction of low-waste operations is the subject of a new law being formulated by the Russian Federation. The law calls for the regulation of waste production, with the creation of well-defined systems directed towards the organisation of low-waste operations and the decrease of ecological damage through the use of scientific, technical, economic, legal and administrative measures. Technical improvements
The aim is to improve the metallurigical results achieved by the introduction of new methods and/or technologies. These include:
* The development and introduction of efficient methods of grade control at mines, using in particular methods based on nuclear physics for geologic and technological mapping, radiometric sorting and ore separation.
* The development and introduction of a new generation of crushing, grinding and classification equipment, characterised by high efficiency, a high degree of size reduction, low metal consumption and low energy requirements. Included in this programme are primary, secondary and tertiary cone crushers; fine crushers, cone inertia crushers, ball mills of up to 320 |m.sup.3~ volume, screens with areas of up to 29 |m.sup.2~, and cyclones of up to 1.4 m diameter.
* Large flotation cells of 40 |m.sup.3~ are being introduced at Norilsk, and others of 16 |m.sup.3~ at the Almalic, Gai and Uchali plants, while column cells are also being introduced at Uchali.
* At a number of concentrators, new effective reagent regimes have been introduced for the separation of bulk flotation concentrates, plant operation now incorporating full water recycling. Also in the flotation sections, new systems have been developed for the automatic regulation of pulp based on the creation of new physical/chemical models of reagent/mineral interactions, in addition to the used of selective-acting electrodes.
* In smelting, as has been mentioned, a new oxygen-flame smelting process and fluid-bath smelting for the production of blister copper have been introduced at a number of plants.
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|Article Type:||Industry Overview|
|Date:||Feb 1, 1994|
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