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The Ridder Sokol'noe, (or Ridder Sokolny) polymetallic VHMS deposit lies within the Rudny Altay Volcanic Arc, in the Leninogorsk/Ridder district of eastern Kazakhstan, and is located within the township of Ridder, 235 km east of Semey and 80 km NE of Oskemen (#Location: 50° 21' 18"N, 83° 32' 31"E).
The deposit was originally discovered in 1784 by F Ridder. Oxide ore was mined from 1789 to 1861. Production from sulphide ore commenced in 1885, continuing with minor breaks until 1916 when the increasing influx of water resulted in the cessation of operations. The mine was explored between 1926 and 1944, when large scale production commenced and has continued until the present (Smirnov, 1977).
The Leninogorsk ore field lies on the north-eastern margin of the NW-SE elongated Sinyushinsk volcanic uplift. It is set in a middle Palaeozoic sequence overlying a lower Palaeozoic basement, as follows, from top to base (Smirnov, 1977):
Middle Devonian (Eifelian), comprising:
Sokol'naya Group, >500 m thick - composed mainly of argillites and siltstones with thin members of acid and basic volcanics. Extensive, layered quartz-albitophyres, up to 500 m thick which are found within this group are believed to be intrusive.
Kryukovsk Group, 200 to 500 m thick - mainly silt-pelites, calcareous siltstone, quartzites, siliceous shales, and lavas and tuffs of albitised rhyolite porphyry. This unit is the main host to ore.
Leninogorsk Group, 400 to 600 m thick - acid lavas, lava-breccias and tuffs;
Ordovician - or older, basement
Khankharian Suite, >1000 m thick - sericite-chlorite schists, phyllites and chlorite-carbonate schists;
Ridder Sokol'noe lies within the Leninogorsk ore field which comprises a large graben, surrounded on all sides by major faults, and in part by large post ore thrusts. The sediments and volcanics of the graben have been weakly deformed and in the main have only a gentle southerly dip. Structural studies indicate the presence of two small, north-westerly trending anticlinal-horst blocks within the ore field, separated by a graben. The anticlinal-horsts have been complicated by a series of domal structures with cores of quartz-barite developed below siltstones of the Kryukovsk Group. The Ridder Sokol'noe deposit is located within one of the anticlinal-horsts, while its individual ore lenses are within the associated domes. Five faults are known in the ore field, defining the anticlinal-horsts. They are traceable for distances of 1 to 2 km and dip both to the east and west, with throws of several tens of metres. These structures are apparently syn-depositional, but have been subsequently re-activated on a number of occasions (Smirnov, 1977).
Ore is localised within the sediments of the Kryukovsk Group, mainly hosted by 'quartzites', 'micro-quartzites' and silt-pelites. There are a number of orebodies and groups of orebodies and these have complex forms. The main orebodies or groups of bodies include the 'Central', the '1st, 2nd and 3rd South-western' and the 'Bystrusha', as well as the 'Kryukovsk' deposit. Ore is distributed over a vertical range of 600 m within the host sequence. In the upper levels, the mineralisation is broadly concordant, although towards the base, contacts are uneven and discordant, complicated by downward extending apophyses (Smirnov, 1977).
Ore occurs as massive and "segregated" (semi-massive) sulphide bodies, which are transitional, and as stockwork veinlet types. The massive and segregated accumulations are lensoid and are concentrated in domal structures, associated with quartz-barite developments below the overlying siltstones. The ore textures are said to include, massive, banded, veinlet, secretion, cockade, segregated and streaky. Three ore types are defined, namely Pb-Zn, Cu-Zn and Au bearing. The former predominates. In the Pb-Zn ore the ratio of Pb:Zn:Cu is 1:2.2:0.2, and in the Cu-Zn ore it is 1:4.3:8.1. The principal minerals are sphalerite, pyrite, galena, chalcopyrite, quartz, calcite, hydro-mica, phengite, dolomite and barite. There is a well defined vertical zonation within the orebodies, from an upper barite-polymetallic association, to lead-zinc in the middle and copper-zinc at the base (Smirnov, 1977).
Widespread alteration in the form of silicification, sericitisation, carbonatisation, chloritisation and baritisation is recorded in the ore field, although there is an opinion that the siliceous hosts are not alteration products but primary sediments. Eruptive breccias are also found within the Leninogorsk ore field, occurring as concordant and discordant pipe like bodies, cutting the Leninogorsk, Kryukovsk and Il'ina Groups. They include unaltered fragments of rocks from the lower two units, as well as altered rocks, massive sulphides, vein quartz with sulphides and quartz-barite rocks. These breccias themselves are cut by quartz-carbonate-barite veins with galena (Smirnov, 1977), implying long lived mineralising processes.
Annual production in 1990 amounted to 2.99 Mt @ 1.41% Cu, 0.48% Zn, 0.3% Pb.
Between 1789 and 2008 the Ridder Sokol'noe mine has produced: 180 Mt @ 3 g/t Au, 1.7% Zn, 0.85% Pb, 0.35% Cu, 29.4 g/t Ag.
Remaining resources in 2009 were: 44.6 Mt @ 1 g/t Au, 1.51% Zn, 0.52% Pb, 0.53% Cu, 10 g/t Ag (Yakubchuk and Seltmann, 2012).
Remaining resources and reserves in 2012 (Halyk Finance report, Dec. 2012, sourced from Kazzinc reports) were:
Mineral resources - 104.76 Mt @ 0.5% Cu, 1.0% Zn, 0.4% Pb 10.9 g/t Ag, 1.4 g/t Au;
Ore reserves - 21.0 Mt @ 0.3% Cu, 0.7% Zn, 0.4% Pb 10.3 g/t Ag, 1.0 g/t Au.
The most recent source geological information used to prepare this summary was dated: 1994.
Record last updated: 15/5/2013
This description is a summary from published sources, the chief of which are listed below.
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