S.S. Naumov, A.V. Tarkhanov, G.I. Birka
S.C. “Geologorazvedka”, All-Russian Research Institute of Chemical Technology, Moscow, Russian Federation
Abstract. Priargunsk Mining-Chemical Production Enterprise (PPGHO) is the only active uranium producing centre in Russia. Its nominal annual capacity is 3500 t U. To increase annual uranium production in Russia, three new ISL production centres are planned to come into operation: Transural (Kurgan region), West Siberian (Kemerovo and Novosibirsk regions), Vitim (Republic Buryatiya). New exploration activities are focused on deposits of sandstone and unconformity type discovery.
The policy of Russia in uranium production is reviewed in the “Red Book 1997” and did not changed significantly since that time.
For the present moment there is only one enterprise in Russia that is engaged in uranium ores mining and processing - “Priargun mining - chemical manufacturing association”, that is located in Krasnokamensk, Chita region. The most part of ores is processed at hydrometallurgical plant, with the nominal capacity of about 3500 t/y. About 90 tonnes of uranium is mined by In Situ Leaching (ISL) method and about 500 tonnes - by heap leaching method. It is planning that the role of heap leaching method will be steadily growing.
In order to increase uranium production in Russia there have been planning to start 3 additional uranium production centres: Transurals (Kurgan region), West-Siberian (Kemerovo and Novosibirsk regions) and Vitimsky (Buryatiya). At these deposits uranium will be mined by in-situ leaching method through wells (Fig. 1).
One of the deposits (Dolmatovskoye) in Transurals region (Fig. 2) has been fully explored.
Preliminary prospecting jobs are carrying out at the second deposit - Dobrovolskoye. The third deposit - Khohlovskoye -is at the stage of estimation. The speculative resources of these three deposits is about 40 000 tonnes of uranium. There are quite positive capabilities for increasing the mineral potential of the region up to 80 000-100 000 tonnes.
The installation for ISL production has been completed. The starting annual production will be 100 m tU. The stand by processing plant has been restored and wellfield unit is prepared for leaching.
The production volume of Transurals region could be increased within the period of 5-7 years up to 700 tonnes of uranium. In Transurals region Dolmatovskoye deposit could be considered as the most prospected one.
The deposit is bedded mainly in the cut of West-Siberian platform in sedimentary cover paleovalley formed by Middle-Upper-Jurassic alluvial sediments. The uranium injection is controlled by the border of bed oxidizing zone in water-bearing sand-gravely sediments (Fig. 3).
Orebodies are located in paleovalley and its tributary. The total length of uranium injection is about 25 km at a width of 1.5 km. The ore deposit depth is 360-500 m (Fig. 4). In drawing the orebodies has stripe shapes, often telescoped vertically and divided by water packer. In the cross-section it is the set of ore lenses, sometimes multilevel, rarely it is common rolls with clearly distinguished sack part.
The ore mineralization is introduced by coffinite and pitchblende. Uranium average content is 0.039%. At high concentrations in ores there could be scandium, molybdenum, rhenium and REE.
1) Depleted centre; 2) Modern centre; 3) Future centres.
FIG. 1. Uranium production centres of Russia.
West Siberia ore regionis introduced by uranium deposits of infiltration genesis type, located in platform deposition of Late Jurassic-Early Cretaceous age (Fig. 2). Only at one of these deposits - Malinovskoye - there were carried out the prospecting and evaluation jobs. It is located in paleovalley (Fig. 5) cut into Paleozoic foundation rocks. The thickness of Mesozoic-Cenozoic depositions in paleovalley is about 300 in average. Bed type uranium orebodies are located in Bazhenovsky horizon (J3 - K1) with the thickness of about 70-120 in (Fig. 6). It is composed of sands with different grains size, gravel and boulder-pebble depositions of bed fractions that contain carbonoficated vegetable residuals even in the form of brown coal thin layers (0.1-0.5 m).
The bed type deposition is about of 50 m of thickness, its length is 2.5 km., width is 100 – 300 m, uranium content is about 0.013 – 0.139%. The basic uranium minerals are coffinite and pitchblende.
The experimental tests for ISL are carried out at the present time. The results will be the base for evaluation of the future production center capacity. The resources of Malinovskoye deposit are estimated as 20 000 tonnes of uranium while the total West Siberia resources make about 180 000 tonnes of uranium.
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1) West Siberian platform; 2) Uranium-bearing regions; 3) Boundary of Russia; 4) Uranium deposits:
1) Dolmatovskoye, 2) Dobrovolnoye, 3) Malinovskoye.
FIG. 2. Position of valley-type uranium deposits on West Siberian platform.
1-2) Folded complex (Pz) of basement: 1-liparites, tuffs, carbonaceous and siliceous shales;
2) Basalts, tuffs, limestones; 3) Platform complex (J(2-3)) filling up paleovalley; 4) Content of uranium
>0.01%; 5) Uranium orebodies (>0.08m%); A-B Line of cross-section.
FIG. 3. Dolmatvosky uranium-bearing area.
1) Clay; 2) Diatomite; 3) Opoka; 4) Opoka with clay lenses; 5) Chalky clay; 6) Quartz-glauconitic sand; 7) Quartz-feldspathic sand; 8) Drift Clay; 9) Coarse sand; 10) Boulder sand; 11) Basalt;
12) Limestone; 13) Shale; 14) Orebody.
FIG. 4. Geological cross-section of Dolmatvoskoye deposit.
Vitimsky region is located 140 km to the North of Chita in the borders of Amalatsky Plato, between Vitim river and its left tributary - Amalat. The uranium injection is timed to paleovalleys of side tributaries of two large paleorivers (Fig. 7). Paleovalley is made of alluvial-prolluvial depositions of Miocene, introduced by clay-sand rocks, clays, tuff, sands and sandstones. Sediments are enriched by organic substances and includes lignites interlayer.
The thickness of these depositions is about several dozens of meters. They are overlapped by Quarterly basalt of 250 m of thickness.
Uranium injections are located in lower layers of sediments at a depth of 150-200 m (Fig. 8).
Orebodies are of stripe shape. The length of the deposition is first kilometers, width is hundreds of meters, thickness is first dozens of meters. Uranium content is about 0.05%. All in all there have been found 11 deposits.
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1) Upper level platform complex; 2) Alluvial depositions of paleovalleys (J3-K1); 3) Lower level platform complex; 4) Granitoids; 5) Faults; 6) Malinovskoye deposit.
FIG. 5. Malinovsky uranium-bearing region.
1) Clays, sands (K2); 2) Clays (K1); 3) Alluvial depositions (K1-J3); 4) Rocks of basement;
5) Orebody.
FIG. 6. Geological cross-section of Malinovskoye deposit.
1) Alluvial depositions of paleovalleys (Miocene); 2) Rocks of basement; 3) Orebodies; 4) Faults.
FIG. 7. Vitimsky uranium-bearing region.
1) Basalts; 2-3) Alluvial depositions; 3) Lower level; 3) Upper level; 4) Rocks of basement;
5) Orebody.
FIG. 8. Geological cross-section of a typical deposit.
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content of about 0.05%. The speculative resources of the region make about 100 000 tonnes of uranium. It is possible to construct a new enterprise with the output more 1000 tonnes of uranium on the base of prospected deposits.
The experimental ISL working has been started at Khiagda deposit.
Basel channel (valley-type) sandstone type Sheglovskoye deposit with 8000 mt U EAR2 resources has been discovered in 1998. Its evaluation is in progress.
The Uranium Exploration in Russia is carried out in limited volume. It focused mainly on the discovery of deposits of two types:
— Sandstone-type, which are amenable for ISL,
— Unconformity type with high grade ores.
The geological prerequisites for unconformity type deposit are in the Karelia-Kola region of Baltic shield and in the south-eastern part of Aldan shield. This exploration will be developed further at the all territory of Russia. The most favorable areas are situated in the Voronezh massif, Aldan and Anabar shields and in Altai-Sayan fold belt.
BIBLIOGRAPHY
DOLGUSHIN, P.S. et. al, “Malinovsk deposit of uranium”, National Geology, No. 9, 1995.
KONDOATJUKIN, A.D., MODNIKOV, I.S. et. al, “Uranium deposit in regions of continental volcanism”, Prospecting and defending mineral resources, No. 5, 1992.
LAVEROV, N.P., “Uranium resources of the USSR”, IAEA Technical Committee Meeting, 22-23 August 1991.
LUCHININ, N.N. et al, “Uranium deposit in paleo-valleys of After-Urals and After-Baikal”, Prospecting and defending mineral resources, No. 5, 1992.
LUCHININ, N.N., et al, “Perspectives of uranium deposit finding in Ural region”, National Geology, No. 9, 1995.
Resources, Production and Demand. A joint report by the OECD/NEA and IAEA, (1993).
The prospected resources of Vitimsky region are estimated as 52 000 tonnes of uranium. The largest deposit, Khiagda, has about 15 500 tonnes of uranium resources at an average uranium