Authors: B.I. Benevolski, Doctor of Geological and Mineralogical Sciences, Head of De-partment at the Central Scientific-and-Research Geological Exploration Institute for Non-Ferrous and Noble Metals (Federal State Unitary Enterprise);
I.M. Vitkovski, Lead Research Fellow at the Central Scientific-and-Research Geological Exploration Institute for Non-Ferrous and Noble Metals (Federal State Unitary Enterprise).
Gold. The mineral resources base of gold in Russia laid in mainly during previous years is sufficient in its bulk to build up domestic gold mining in the longer term. It is composed of reserves harbored by genuine gold ore deposits (5 700 tons), complex deposits (2 600 tons) and alluvial de-posits (1 400 tons).
The greatest reserves of gold (59%) are concentrated in genuine gold ore deposits, 27% in complex deposits and 14% in alluvial deposits. The state register (as of 01.01.2007) accounts of 5 801 deposits, including: 248 gold ore deposits, 128 complex deposits and 5 425 alluvial deposits, of which 78, 49 and 1 430 accordingly are being mined. The distributed fund contains 76.2% of re-serves belonging to gold ore deposits, 53.0% of reserves belonging to alluvial deposits and 83% of reserves belonging complex deposits. There is a great part of reserves assigned to the undistributed fund of alluvial deposits (47%).
The major amount of gold (56.5%) is extracted from gold ore deposits, 12.5% from complex deposits and 31% from alluvial deposits. Starting from 2001, mining from gold ore deposits ex-ceeded alluvial mining and in 2006 reached 55.3%.
The total quantity of predicted resources (Р3+Р2+Р1) in gold ore deposits amounts to 83%, while in complex deposits it reaches 6% and in alluvial deposits 11%.
Thus, the existing raw material base and gold mining are mainly localized on the genuine gold ore deposits, which are promising for further development of the gold mining industry.
The inter-temporal changes in gold ore deposits in 1991-2007 are characterized by a 33.5% increase in the АВС1 categories, including 4.5% in the Siberian Federal District and 74.6% in the Far Eastern Federal District, mainly based on re-evaluating the Natalkinskoye Field and on explora-tion of the Blagodatny Field. The С2 category reserves went up 19.7%. The total reserves growth (АВС1С2) reached 28.4%. The overwhelming part of reserves is focused in the Siberian (43%) and Far Eastern (51.5%) Federal Districts. Taking into account the re-evaluated reserves of the Sukhoi Log Field, the share of the Siberian Federal District is rising to 51%.
75% of the total reserves (АВС1) are in the distributed fund, of which 30% belong to depos-its under development, 45% to deposits being prospected and prepared for development. The undis-tributed fund comprises 25% of the backup inventory. The Sukhoi Log Field accounts for over 70% of АВС1С2 reserves in the undistributed fund. If this field will be licensed, the undistributed fund will virtually be exhausted! Six out of 248 very large and large deposits take in 68% of all the stock. This situation indicates that today large and very large deposits determine the way of devel-oping and reproducing the mineral resources base of lode gold. At the same time, it is impossible to write off medium-size and small deposits, which serve the existence basis for companies providing additional jobs and solving a range of social problems.
In 1991-2006, the lode gold output went up from 28.5 tons to 119.9 tons. The output growth of 34.5% in 2006 was mainly due to the third extension of the strip mine put into operation in the Olimpiadninskoye Gold Field (5 million tons of ore per year). The major part of gold was mined in medium and small scale deposits, but after Sukhoi Log and Natalkinskoye as well as Blagodatnoye and Kupol will be put under development the share of large and very large deposits in gold mining will rise at least to 70%. Gold mining is mainly performed in the Siberian (58%) and Far Eastern (32%) Federal Districts.
The inter-temporal changes in reproducing gold ore reserves (АВС1) from 1991 are distin-guished by reducing accrued stock 48% along with the twice declined reproduction rate. In 2005-2007, the gold stock (АВС1С2) grew to 482 tons in 37 new sources, including Kupol and Blagodat-noye rated at 387.4 tons, and taking into account the re-evaluated fields of Sukhoi Log and Na-talkinskoye – to 2 071 tons. About 330 tons of gold was produced in the same period. The coeffi-cient of compensating gold mining by stock accrual was less than one starting from 1995, e.i. stock accrual was lagging behind mining; in 2005, the accrued stock was slightly ahead of mining, while in 2006, this coefficient reached the value of 10 (Natalkinskoye) and in 2007 it was even higher (Sukhoi Log).
Of the total number of gold ore deposits (248), 78 are under development, 74 belong to the state reserve, 33 are being prospected and 63 are being arranged for development. The АВС1С2 gold stock in gold fields under development accounts for 32% of the total gold stock in the Russian Fed-eration, including 18% of the stock distributed between 19 major enterprises (producing more than one ton of gold) or 54% of the stock belonging to all the deposits under development. The total gold output in 2006 yielded by 19 major enterprises reached 84.0 tons or 70.6% of the total lode gold output. The rest of the enterprises produced 29.4% of gold, and this was of no significant influence on the inter-temporal changes. The major non-ferrous enterprises engaged in developing primary gold deposits are mainly grouped in the Urals, Siberian and Far Eastern Federal Districts.
The duration of prospected reserves (АВС1) for major enterprises ranges from 2 to 13 years. If the subsoil stock being now mined will not be replenished and if the 2006 gold output level will be maintained, 14 (out of 19) currently operating major enterprises will exhaust their stock and the annual gold output taken as a whole will decrease to 90 tons.
Consequently, the raw material base of the currently pace-setting enterprises in the period of 2007-2025 does no allow maintaining the existing output level, to say nothing if its buildup. This task must be solved at the expense of deposits, which are being prospected and prepared for devel-opment or at the expense of backup deposits, as well as by means of discovering new fields in the course of prognostic and prospecting works.
The group of backup primary gold fields includes 170 deposits (among them state reserve deposits, deposits currently being prepared for development and deposits under prospecting). They account for 88% of the total reserves (АВС1С2) in Russia and are mainly concentrated in the Sibe-rian and Far Eastern Federal Districts (85%). The most significant of them are Sukhoi Log, Blago-datnoye, Maiskoye, and Kupol, whose aggregate stock of gold metal amounts to 85% of the total inventory in the group.
It is worthy of note that 79.0% of the stock fall on the two largest deposits – Sukhoi Log and Natalkinskoye.
All the above mentioned 16 backup fields are planned to be put under development in vari-ous years in the course of 2007-2025. Their estimated aggregate output is 169 tons per year and it may replenish the depleting output in this period (90 tons) as well as maintain the output growth rate.
The outlook for developing the mineral resources base of lode gold is also tied to availability of predicted resources (PR). The major of them, as well as the stock, are localized in the Far Eastern and Siberian Federal Districts. The PR fields, which are not turned under licensing and not included into the annual federal programs of geological and prospecting works, are in their bulk related to categories Р1-38.8% and Р2- 61.6% and earmarked as a reserve for increasing the stock. In the dis-tributed fund, there are 22.2% of resources belonging to category Р3, 25.2% to category Р2 and 61.2% to category Р1. In the total bulk of predicted resources, gold-sulphide-quartziferous fields of geologically industrial type account for 55.3%, those gold-quartziferous for 20.0%, those gold-argental for 16.6% and auriferous crusts of chemical weathering for 8.1%.
In the existing economic conditions, open-mine fields featuring low gold content and offer-ing possibilities to employ high-end techniques of gold extraction (heap leaching, direct cyanidation of process plant ore, etc.) possess the highest investment attractiveness.
Silver. The mineral resources base of silver in Russia rated as АВС1С2 (112 000 tons) is represented by two groups of deposits – genuine silver deposits and silver containing (complex) de-posits. The genuine silver deposits are the most advantageous, which meet the industrial needs in silver. However, 85 000 tons (76%) of silver stock are enclosed in the complex deposits (containing also copper, lead, zinc, gold, nickel, and other elements), leaving 27 000 tons (24%) to the genuine silver deposits, all of which are located in the Far Eastern Federal District.
Twelve major silver deposits out of 277 contain about 70% of the in-place silver stock rated as АВС1 and their silver output is also equal almost to 70%. The first place in terms of silver stock is occupied by the Siberian Federal District – 45.6%; the Far Eastern Federal District is in the sec-ond place – 31.7%; and the Privolzhsky Federal District – 16.1%. The first place (22.3%) among the constituent entities of the Russian Federation is occupied by the Magadan Region due to its genuine silver ore stock (the Dukatskoye, Lunnoye and other deposits); the second place (13.5%) is won by the Chita Region (the Udokan cupriferous sandstone deposit, the Bugdainski copper-molybdenum ore deposit, and others); the third place (10.2%) is kept by the Republic of Buryatia (the Ozernoye and Kholodninskoye complex ore deposits).
The distributed fund accounts for 73% of АВС1С2 silver stock. By their development grades, 161 deposits are rated as being under development and prepared for development, 11 as being pros-pected and 105 as assigned to the state reserve (undistributed fund).
Predicted silver resources in the genuine silver ore deposits account for 80% of the predicted resources of the Russian Federation, of which 90% belong to the Far Eastern Federal District. The predicted resources of the genuine silver deposits are involved in the licensing process to mere 19.0% committing the Dukatski and Western Verkhoyansk silver ore areas.
In 2006, silver mining covered 103 deposits and produced 1 443 tons of silver. Complex de-posits are prevailing in mining works – 822.5 tons (57%). By 2005, the silver output increased 1.6 times, including an almost tripled growth in the genuine silver fields and a 1.2 times growth in the complex silver fields. The Far Eastern Federal District is leading in silver output (64.7%); the sec-ond is the Privolzhski Federal District (12.6%) and the third is the Siberian Federal District (11.5%). Among the constituent entities of the Russian Federation the first place (47.7%) is kept by the Magadan Region, where genuine silver mining amounts to 42.4%. It is followed by the Kha-barovsk Territory (12.3%) with its Khakandzhinski Silver Field. The third is the Taimyr Autono-mous District featuring complex ore deposits of the Norilsk group. It should be noted that all the companies developing silver fields are involved in “predatory mining” of exclusively rich silver ore compared with its medium quality in the stock. Thus, ZAO Serebryanaya Compania engaged in de-veloping the Tidid Field with an average silver content of 692.3 g/t is mining ore with a silver con-tent of 1300 — 2333 g/t, while ZAO Serebro Magadana developing the unique Dukatskoye Field with an average silver content of 643.7 g/t is mining ore with a silver content from 901 g/t to 1378 g/t.
The duration of prospected reserves for companies developing silver fields is from 10 to 24 years. By 2025, the output of genuine silver ore deposits will decrease by 121 tons due to their de-pletion. The duration of complex deposits will depend on the basic metal content and taking into account the depletion of stock reserved for copper, lead and gold mining enterprises by 2025 the silver output will drop by 400 tons. The aggregate decrease in output will exceed 500 tons.
Reserve silver fields are represented by deposits being prepared for development (68) and by deposits listed in the undistributed fund of the state reserve.
However, if the deposits being prepared for further development and those assigned to the state reserve of silver deposits will be put into industrial operation and taking into consideration the remaining capacity of the silver deposits currently under development, the annual silver output by 2025 may reach 1 000 tons. The annual output based on complex ores by 2025 may also be in-creased up to 1 100 – 1 200 tons on condition the scheduled deposits being prepared for further de-velopment as well as reserve copper, lead, zinc, nickel and gold fields will be put into operation and also taking into account the remaining capacity of the deposits currently under development.
Platinum group metals. The mineral resources base of the platinum group metals (PGM) in Russia is also an important component of the world mineral resources sector being in the second place in terms of PGM stock and output and in the first place in terms of palladium stock and out-put. The in-place PGM stock of Russia is registered in 98 deposits and accounts for 13 300 tons. There are two groups of deposits delineated in the pattern of the mineral resources base: these are primary and alluvial deposits, which in their turn are divided into genuine and complex deposits, where PGM are registered as associated components.
The core of the PGM mineral resources base is composed of primary deposits rich in pre-vailing palladium (up to 74%). It is noteworthy, that proper platinum-palladium deposits assigned to PGM (the so called low-sulphide type) have no substantial role played in the mineral resources base of Russia (as distinct from South Africa, the world’s major PGM producer) and until recently were represented by resources only. In 2006, the stock of the two deposits associated with the Fedorovo-Panskoye stratified mass on the Kola Peninsula was taken up for current accounting. The leading position is occupied by the copper-nickel deposits of the Norilsk Region containing 97% of the in-place PGM stock. Platinum-bearing ores of the Norilsk deposits are divided into three industrial types: solid, impregnated and “cupriferous” ores. Of profound importance are solid and “cuprifer-ous” ores featuring high contents of PGM (9-12 g/t), nickel (1-4%) and copper (up to 5%), but the stock of these deposits is dominated by impregnated ores.
The PGM stock in deposits located in the Russian Federation are wholly characterized by a high degree of prospecting and industrial development: the А+В category accounts for 39.2% of the prospected deposits rated as А+В+С1, while the А+В+С1 and С2 categories – 67.4% and 32.6% of the total amount accordingly. More than 87% of the in-place PGM stock is handed over to subsoil users. Out of 98 deposits, 25 are under development, 20 are being prepared for further development and 5 are being prospected. The undistributed fund contains an insignificant part of in-place re-serves belonging to primary complex deposits.
Virtually all the mining of primary PGM is based on copper-nickel ores of the Norilsk de-posits (99.5%). In 2006, there were produced 154.4 tons of PGM, including 149.3 tons in the com-plex fields and 7.1 tons in the alluvial fields. Starting from 1992, the raw material base of primary PGM is noted for a stable trend to depletion, which is the consequence of a negative balance be-tween mining and reserves accrual. The duration of total prospected stock in primary deposits for mining purposes (at the actual mining rate of 2006) is estimated as 59 years, including 16 years for solid ores, 26 years for “cupriferous” ores and 260 years for impregnated ores.
The predicted resources (PR) of primary PGM (3 600 tons) re-calculated into the conven-tional С2 category account merely for about 8% of the in-place reserves. Their major part, as in the re-serves, is composed of predicted resources associated with complex copper-nickel ores (2 500 tons). The predicted resources of platinum-palladium deposits (1 140 tons) are virtually all localized in the North-Western Federal District on the territories of Karelia (20.5%) and the Murmansk Region (79.5%).
Replenishment of predicted PGM resources with primary deposits of the undistributed fund is lim-ited by the high degree of geological exploration maturity of traditional nickeliferous areas and by the ab-sence of new potentially yielding areas promising of platinum-palladium deposits in the Russian territory (with regard to the current level of geological exploration maturity).
The state, usage and reproduction of material resources base (MRB) for alluvial platinum in Rus-sia is determined by the appropriate MRB indicators of the Far Eastern Federal District. The platinum stock in the Urals Federal District, although it is in the first place in this respect, is spread between 77 small alluvial deposits, the greater part of which is assigned to the undistributed subsoil fund, while small-scale deposits with low platinum content are not attractive from the point of view of investments.
The duration of total prospected stock in alluvial deposits for mining purposes (at the actual 2006 mining rate of 7.1 tons) is estimated as 3.5 years; this indicator for the Far Eastern Federal District is 1.7 years, including 2.5 years for the Khabarovsk Territory, and less than one year for the Koryak Autonomous District.
A key tack in solving the MRB problems of noble metals is associated with setting up large-scale diversified centers of the mining and processing industries (clusters) in the most promising areas – in the south of Siberia, in the Far East, in the south region of Russia and in some other areas. Implementation of such large-scale projects based on private and government partnership will permit to lay the groundwork for alternative MRB making possible long-term economic development, protection of geopolitical inter-ests on the outskirt territories, and solution of social and economic problems in depressive and high-tension regions.
For efficient solution of the MRB reproduction problem in relation to primary gold, it is important to fulfill a complex of foreground prognostic-and-prospecting tasks in the first place in the following areas: on the southern margins of the Siberian Platform – in the Altai-Sayanski District, in Eastern Sayan, and the Northern Baikal Region; in the Far East – in the Yano-Kolymski and Chukotski Districts, in the Polar-Urals and Northern Caucasus promising regions, where it necessary to localize a resources base (belong-ing mainly to the P1 category) providing for reproduction of reserves; to stabilize the MRB of alluvial gold – in traditional alluvial mining areas at the expense of exploration and development works in the vicinity of established deposits, evaluation of non-traditional types of alluvial deposits in new promising areas, re-vision and re-evaluation of discovered reserves and updated large alluvial deposits (Ryveyem and others) in old areas, and evaluation and implementation of technogenic alluvial deposits.
The problem of increasing the output of primary gold and reproducing the MRB may be solved by way of large-scale deposits with low gold content and establishing world-level gold and silver mining in-dustrial centers – the Yano-Kolymski (estimated at 5 000 tons of gold), Altai-Sayanski, Chukotski centers and others.
Despite the sufficiently stable state of domestic silver reserves in silver and complex argentiferous deposits, the domestic silver output in the recent decade of the 20th century decreased approximately two times. 94% of stock related to genuine silver deposits and more than one half of stock related to argen-tiferous deposits are in the distributed fund. After launching the Dukatskoye Field in the Magadan Region and the Khakandzhinskoye Field in the Khabarovsk Territory, the silver output in this country exceeded one thousand tons.
Federal interests in reproducing the silver MRB are chiefly connected with the opportunities of discovering deposits in the promising structures of the Okhotsko-Chukotski volcanogenic belt, as well as with the evaluation of the new large-scale silver ore province in Western Verkhoyanye (the Republic of Sakha), where there may be established an alternative silver ore base evaluated at 60 000 tons of silver.
The domestic output of PGM after the recession of 1990-1996 reached the 1990 level. The alluvial deposits of Koryakia and the Khabarovsk territory made a significant contribution to this growth. Virtually all the mineral resources base of PGM is currently in the distributed fund and its development rate is wholly dependent on OAO GMK Norilski Nickel, the monopolistic company not only on the national level, but across the globe.
Federal interests in developing the PGM material resources base are determined by the necessity of establishing alternative MRBs to preclude national-level losses in case of decreased PGM production in the Norilsk area. Promising territories in the Murmansk Region, Karelia, peripheral areas of the trappean fields in the Siberian Platform along with nickeliferous and platiniferous structures of the Eastern Sayan Mountains happen to be priority areas for geological exploration works, where there are manifestations of PGM and associated geological environment. Implementation of a large-scale Eastern Sayan project will permit to set up an alternative raw material base related to nickel, copper and PGM with contingent re-sources of 445 000 tons of nickel, 165 000 tons of copper and 26 tons of platinum respectively.