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Belinsk, Vostochno-Ayatskoye, Ayatskoye |
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Kazakhstan |
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Al
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Super Porphyry Cu and Au
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IOCG Deposits - 70 papers
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All papers now Open Access.
Available as Full Text for direct download or on request. |
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The Belinsk bauxite deposit, is located in the west Turgay bauxite region of north-western Kazakhstan, 200 km south of the Turgay iron ore province, ~270 km SE of Magnitogorsk (#Location: 52° 21' 39"N, 62° 35' 27"E).
The underlying sequence is Palaeozoic in age and comprises, from the base (Smirnov, 1977):
Lower Carboniferous, including - a). limestone, b). andesite and andesitic-basalt, porphyry, tuffs, tuffaceous sediments, tuff-breccias and tuffaceous sandstone, c). Lower Carboniferous diorite, quartz-diorite and dioritic porphyry. These volcanics and intrusives belong the Valerianovsk Magmatic Belt.
Middle & Upper Carboniferous - red bed polymict conglomerate, sandstone, siltstone and argillite.
Triassic - basalt and basaltic porphyry.
The Mesozoic and Cenozoic bauxite bearing sequence which unconformably overlies the Palaeozoic, comprises:
Late Cretaceous (Cenomanian to Turonian) - bauxite bearing sediments, mottled bauxitic and proluvial-eluvial clays, bauxitic rocks and bauxite.
Palaeocene and Quaternary - clays and sand cover.
In the centre of the deposit, the Carboniferous basement has been broken up into a series of fault blocks, resulting in alternating fault bounded belts of limestone and volcano-sedimentary rocks. A weathering crust of kaolinite and hydromica-montmorillonite clays is everywhere developed over the Palaeozoic basement. The maximum thickness of weathering is up to 60 m, developed in the zones of faulting separating rocks of different composition. Fault bounded depressions/basins filled with bauxite-bearing sediments, are developed over carbonate rocks adjacent to zones of stratigraphic and faulted contact between the carbonate and mafic pyroclastic rocks (i.e., adjacent to zones of maximum weathered bedrock). The bauxitic sediments are overlain by late Eocene clays, Oligocene sandy and argillaceous sediments, and Quaternary loams. The total overburden is from 6 to 55 m (Smirnov, 1977).
The bauxite bearing sediments comprise interlayered mottled kaolinitic and bauxitic clay, allite (a leached rock from which silica has been removed, leaving a high Al and Fe content), carbonaceous clay, and stony, argillaceous and friable bauxite. The total thickness of bauxite bearing sediments is 170 m, although the bauxite is concentrated in the upper section, with argillaceous sediments in the lower parts. Although the bauxitic sequence is Cenomanian to Turonian (lower late Cretaceous), the major bauxite formation was in the Turonian (Smirnov, 1977).
Some 26 ore enclosing basins have been outlined, varying in shape and size from karst funnels 50 to 60 m across, to larger, almost circular depressions 1500 m long and 300 to 700 m wide. In each basin there is a single development of bauxite consisting of two or three lens like main, and several subsidiary, orebodies. In all, 230 bodies of mineralisation have been outlined, 128 of which are regarded as being commercial. Of the three bauxite types, 30% is friable, 30% stony and 36% is argillaceous. Towards the edge of the basins, the bauxite is replaced by bauxitic and mottled clay. In general the stony bauxites form the upper portions of the deposit, while the argillaceous varieties are near the base, in depressions (Smirnov, 1977).
The bauxites are composed of 50 to 70% gibbsite, 2 to 20% kaolinite and 10 to 23% hematite and hyrohematite. There is also 1 to 5% corundum, up to 3% quartz, up to 1.5% calcite, up to 10% siderite and 1.7 to 2.9% rutile. The composition of the bauxite is: 40 to 47% Al2O3, 5.7 to 9.6% SiO2, 12.8 to 23.9% Fe2O3, 1.8 to 2.3% TiO2, 0.3 to 1.6% CaO. The ores are hydrochemical, amenable to the Bayer method, or Bayer-sintering, with only minor 'metallurgical' ore (Smirnov, 1977).
Production in 1993 amounted to 1.18 Mt @ 42.5% Al2O3.
Remaining ore reserves and mineral resources at December 31, 2012 (ENRC Annual Report, 2012), were:
Proved + probable reserves - 6.7 Mt @ 42.3% Al2O3;
Measured + indicated + inferred resources - 7.1 Mt @ 42.5% Al2O3.
The Vostochno-Ayatskoye and Ayatskoye deposits are located 50 km to the NNE of Belinsk (#Location: 52° 45' 43"N, 62° 47' 02"E).
These deposits are essentially the same as those at Belinsk, occurring as bauxitic sediments developed over a Palaeozoic basement of Lower Carboniferous carbonate and Devonian terriginous sediments. At Ayatskoye, the average mineable bauxite layer is 2.9 m thick, with 40 to 60 m of overburden.
Remaining ore reserves and mineral resources at December 31, 2012 (ENRC Annual Report, 2012), were:
Ayatskoye - proved + probable reserves - 6.0 Mt @ 44.8% Al2O3;
Ayatskoye - measured + indicated + inferred resources - 6.3 Mt @ 45.1% Al2O3.
Vostochno-Ayatskoye - proved + probable reserves - 38.0 Mt @ 44.1% Al2O3;
Vostochno-Ayatskoye - measured + indicated + inferred resources - 42.2 Mt @ 40.3% Al2O3.
The most recent source geological information used to prepare this decription was dated: 1977.
Record last updated: 10/9/2013
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd. Unauthorised copying, reproduction, storage or dissemination prohibited.
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