|
Kounrad, Qonyrat, Konyrat, East Kounrad |
|
|
Kazakhstan |
| Main commodities:
Cu Au
|
|
 |
|
|
 |
Super Porphyry Cu and Au
|
IOCG Deposits - 70 papers
|
All papers now Open Access.
Available as Full Text for direct download or on request. |
|
|
The Kounrad porphyry Cu-Au deposit (also known as Qonyrat or Konyrat) is located in the 'Balkhash-Ili' zone of the Upper Palaeozoic Kazakh-Mongol magmatic arc. It is 10 km north of the town of Balqash on the northern shore of Lake Balkhash, in Kazakhstan and 450 km NNW of Almaty (#Location: 46° 59' 29"N, 74° 59' 1"E).
The Kounrad East (also known as East Qonyrat or East Kounradskiy) porphyry molybdenum deposit is located ~11 km to the east of Kounrad.
Kounrad
Kounrad is the largest of a group of deposits, in the district, which also include Kaskyrkazgan and Ken'kuduk. Prior to mining, the Kounrad deposit is believed to have totalled more than 800 Mt of ore averaging 0.62% Cu, and locally up to 0.76 g/t Au. Much of the ore removed from the open pit up until 1996, when it covered an area of 2.2 x 1.8 km and was 330 m deep, was supergene enriched to depths of 54 to 450 m below the surface (generally 150 to 200 m thick), with grades of up to 1% Cu. The remaining reserves in 1996, primarily of hypogene mineralisation, were 220 Mt @ 0.35% Cu, 0.1 g/t Au, 0.005% Mo (Seltmann et al., 2004; Mutschler et al., 2000; Kudryavtsev, 1996; Zvezdov et al., 1993) .
Remaining resources published for Kounrad in the Competent Persons report by IMC Consultants to Kazakhmys plc, (2011) comprise:
Indicated+inferred resources - 169 Mt @ 0.32% Cu, 0.38, g/t Ag, 0.02 g/t Au, 0.01% Mo
Geology
The Kounrad ore deposit is related to the intrusion of Middle Carboniferous (~330 Ma) granitic bodies into a sequence of Late Devonian (Famennian) to Early Carboniferous (Tournaisian) sedimentary, volcano-sedimentary and volcanic units and coeval pre-orogenic granitic rocks, as well as early orogenic Middle Visean (Early Carboniferous) volcanics and associated intrusives. Late Carboniferous granites of the East Qonyrat pluton that are found to the northeast of the deposit are post ore and late orogenic. The upper contact of the East Qonyrat pluton dips to the southwest at around 50° to pass below the ore deposit (Kudryavtsev, 1996).
The volcano-sedimentary sequence commenced with a monotonous grey to greenish-grey polymict sandstone of Famennian age, which passes upwards into Lower Tournaisian greenish-grey tuffaceous sandstone and siliceous siltstone, with intercalated dacitic and andesitic volcanics and thin lenses of crinoidal limestone. Andesitic tuffs and lavas increase and predominate in the upper sections of the latter unit. In the western part of the district, the Tournaisian is more than 1000 m thick and is overlain by intensely altered felsic volcanics (massive rhyolitic tuff, flow banded, spherulitic and amygdaloidal rhyolitic lava flows and flow banded rhyolitic lava) which define a domal structure, the core of which is occupied by the mineralised porphyritic granodiorite.
The felsic sequence is composed of a lower massive rhyolitic tuff, overlain by flow banded, spherulitic and amygdaloidal rhyolitic lava flows, and finally by flow banded rhyolitic lava into which the mineralised granodiorite porphyry has been intruded. The upper two units are as much as 700 m in thickness (Kudryavtsev, 1996) and have been altered to quartz, quartz–alunite, quartz–sericite and diaspore–pyrophyllite, which are the result of syn- and post-volcanic
hydrothermal activity (Zvezdov et al., 1993). This alteration is typical of high-sulphidation epithermal systems.
The granitoid rocks in the district are subdivided into the following, from oldest to youngest:
i). Early Carboniferous (Visean) coarse-grained biotite-hornblende plagiogranite which is found in the southern part of the district where it is part of the large Toqrau pluton.
ii). A late Lower Carboniferous (Serpukhovian/Namurian) complex composed of diorite, medium-grained granodiorite and the early porphyritic granodiorite (the main mineralising intrusive dated by the K-Ar method at approximately 335 Ma).
iii). Late, porphyritic granodiorite to tonalite (324 Ma) and associated dykes, which in order of emplacement are composed of granodiorite porphyry, quartz-diorite porphyry and dolerite of Middle Carboniferous age. All are intra-ore and are consequently both mineralised and altered. The dykes are a few, to a few tens of metres in thickness and may be up to 1 km in length. Shen et al. (2017) date the host intrusion at Kounrad at 331.7±2.2 Ma.
iv). Late Carboniferous, coarse-grained, post mineralisation granitic rocks of the 300 to 285 Ma East Qonyrat pluton (Kudryavtsev, 1996). This intrusion is related to the East Kounrad porphyry Mo deposit and has been dated by Shen et al. (2017) as 295.4±2.9 Ma.
The main structural elements of the district are northwest and northeast trending faults which control the direction of dykes and intrusive margins (Kudryavtsev, 1996). The main ore deposit is related to the northeast elongated, 1100 x 700 to 800 m northern stock of early porphyritic granodiorite, which intrudes Tournaisian volcano-sedimentary rocks on its eastern margin, and altered felsic volcanics on the remainder of its perimeter. The mineralised stock has undulose steep to vertical contacts and tapers slightly with depth. The contact has numerous dyke like apophyses of granodiorite porphyry extending up to 250 m outward from the main stock margin (Kudryavtsev, 1996).
Breccia pipes and pebble dykes of several stages are widespread, but are best developed in the eastern part of the deposit. The early hydrothermal breccias contain sub-rounded clasts of variably altered early porphyritic granodiorite, with lesser altered volcanics and quartz-andalusite rocks set in a matrix of quartz-sericite aggregate containing sulphides. The early breccias are cut by diorite porphyry dykes and by late breccias which are characterised by angular clasts of the same lithologies as in the early breccias, but in addition include fragments of the dykes that cut those breccias. The early granodiorite porphyry clasts are mineralised. The late breccias are cemented by a phyllic altered sand sized matrix with finely disseminated sulphides and veinlets of grey to white quartz containing barite and sulphides. These are in turn cut by pebble dykes that are widespread in the eastern part of the deposit and contain well rounded fragments cemented by a sandy to silty matrix and in addition to the lithologies of the mine area, contain exotic granite and granophyre clasts (Zvezdov et al., 1993; Kudryavtsev, 1996).
Mineralisation and Alteration
The Kounrad ore deposit is largely restricted to the early granodiorite porphyry body, with lesser mineralisation in the enclosing country rocks and virtually none in the silicified rhyolites. It has a generally northwest elongation, reflecting the orientation of the host intrusive, with dimensions of approximately 725 x 1050 m. Higher grade hypogene mineralisation (>0.8% Cu) is concentrated towards the outer margin approximating an annular shape with a lower grade (<0.8% Cu) core. This higher-grade annulus coincides with the more heavily fractured outer sections of the host granodiorite porphyry.
The bulk of the mineralisation is present as uniformly disseminated sulphide grains which vary from several µm to several mm, averaging 0.2 to 0.5 mm, and as ore bearing stockwork veinlets of grey, greyish-white and white quartz containing sulphides and ranging from several tenths of a mm to 100 mm in thickness. At deeper levels stockwork veins are reported to thicken, although their frequency diminishes. The ore stockwork takes the form of a 200 to 400 m thick, sub-horizontal layer with an undulose lower surface, and thicker cores of high grade related to downward protrusions of the base of the zone. This morphology has been interpreted to represent a series of overlapping downward tapering cones (Kudryavtsev, 1996).
Hypogene mineralisation has been overprinted by a pronounced supergene profile, comprising an oxidised cap of from 2 to 50 m in thickness, averaging 20 m, underlain by a preserved leached zone of 7 to 56 m, averaging 32 m in thickness. Below the leached zone, a supergene enriched chalcocite blanket extends to depths of 350 to 450 m in the western apart of the orebody, to 54 to 144 m below the surface in the eastern part (Kudryavtsev, 1996). The oxide cap contains hematite, jarosite and other limonites, cuprite, melaconite, native copper, brochantite and chrysocolla, while the zone of secondary enrichment is characterised by chalcocite and covellite (Zvezdov et al., 1993).
The primary sulphide assemblage within the disseminated and stockwork ore comprises: pyrite, chalcopyrite, molybdenite, enargite, tetrahedrite and hypogene chalcocite, with accessory sphalerite, galena, bornite and magnetite, and rare covellite, arsenopyrite, marcasite, pyrrhotite, idaite, colusite, native silver, native gold, tennantite, famatinite, luzonite, stibio-luzonite, ranerite, altaite, valleriite, cubanite, sternbergite, hematite. Although Cu is dominant Mo is present with a Cu:Mo ratio of close to 110 in the hypogene mineralisation. Within the breccia pipes described above, the quartz-sericite matrix of the early breccia contains pyrite, chalcopyrite, bornite, tetrahedrite and molybdenite. The late breccias carry barite, chalcopyrite, molybdenite and rarely sphalerite and galena in a phyllic altered matrix (Kudryavtsev, 1996).
Alteration and mineralisation has been subdivided into three stages, as follows:
i). Early syn- to post-volcanic alteration (quartz-sericite, quartz-sericite-diaspore assemblages) related to fumarolic-sulfataric activity during the final stages of volcanism, prior to the emplacement of the mineralised early porphyritic granodiorite and affects the rhyolites of the felsic volcanic suite. This phase produced a screen of non-reactive volcanics that were to subsequently partially surround the mineralised intrusive and focus the deposition of ore.
ii). A second stage related to the intrusion of the early porphyritic granodiorite. This phase modified the altered felsic volcanics adjacent to the intrusive contact to produce an assemblage of corundum-quartz, quartz-andalusite, quartz-sericite and propylitic minerals, with a late quartz-kaolinite argillic suite. Within the intrusive, alteration of the porphyritic granodiorite was characterised by quartz-sericite accompanying the main Cu-Mo mineralisation, with a propylitic pyritic outer zone. Argillic alteration, related to the final stages of mineralisation is superimposed on quartz-sericite rocks, being most intense in the transition from preceding quartz-sericite to propylitic zones. The early breccia pipes formed during this same interval. This stage of mineralisation and alteration originated at temperatures of from 400 to 240°C, with the early barren veinlet quartz at 400 to 380°C, pyrite at 330°C and tennantite at 240°C.
iii). The final stage related to the late porphyritic granodiorite to tonalite and associated dykes. This stage is also associated with ore development and is characterised by mica-quartz-tourmaline within the porphyritic granodiorite and associated felsic dykes, while albite, K feldspar and biotite were formed within the dolerite dykes. The muscovite-tourmaline assemblage of this stage was formed at 470 to 440°C, while the late milky-white quartz was precipitated when the system had cooled to around 210 to 160°C (Kudryavtsev, 1996; Zvezdov et al., 1993).
Zvezdov et al., (1993) point out that chalcopyrite ore is largely confined to the zones of phyllic and argillic alteration within the granodiorite porphyry, while molybdenite, enargite and pyrite are restricted to areas of argillic and phyllic alteration (with considerable accompanying chlorite) at the outer contact of the porphyritic granodiorite. Molybdenite increases with depth. They add that the galena-sphalerite association is a late feature and is controlled by northeast trending fractures across the Cu-Mo orebody.
East Kounrad
The East Kounrad porphyry Mo–W deposit was mined as an underground operation during World War II. It has/had reserves of >300 Mt @ 0.15% Mo (Sinclair, 1995) with accompanying W, Sn and Be. The deposit has been described as being associated with an early Permain syenogranite stock (Abdulin et al., 1998; Burmistrov et al., 1990; Sinclair, 1995) intruding andesite, dacite and rhyolite and their volcanoclastic equivalents (Abdulin et al., 1998). The syenogranite occurs as a large, 110 km2, intrusion, located in the centre of
the district, is composed of medium-grained and irregular fine-grained granites. The medium-grained granite contains main perthite, quartz, plagioclase and minor biotite. In contrast, the fine-grained granite comprises feldspar, quartz, plagioclase and rare biotite (Li et al., 2016; Shen et al., 2017). The ore-forming rocks at East Kounrad deposit belong to a series of highly fractionated high-K calc-alkaline, metaluminous to slightly peraluminous I-type granites (Heinhorst et al., 2000; Li et al., 2016; Shen et al., 2017). In addition, Carboniferous quartz diorite, granodiorite, granophyres as well as several dolerite dykes are widespread within the district (Kröner et al., 2008; Li et al., 2016). Accessory minerals within the granite are dominated by magnetite, ilmenite, apatite, titanite, zircon and monazite (Cao et al., 2018, Li et al., 2016).
Shen et al., 2017 described the host rocks as medium-grained (2 to 3 mm) K feldspar, plagioclase, quartz and minor biotite granite and fine-grained (1 to 2 mm) K feldspar, plagioclase, quartz and rare biotite leucogranite. Both have an equigranular hypidiomorphic texture and were emplaced during the early Permian at 295.4±2.9Ma. These host intrusives have undergone potassic and silicic alteration (K feldspar-biotite-quartz) in the core of the granite and leucogranite, surrounded by phyllic alteration (quartz-illite-muscovite-carbonate). Chloritic propylitic alteration extends for hundreds of metres beyond the phyllic and potassic zones. Irregular overprinting argillic alteration (kaolinite) is also evident (Sinclair, 1995).
A NE-trending, pre-mineral, fault divides the large intrusion into two almost equal parts, with East Kounrad being located in the eastern half. Numerous steep fractures with a range of strikes host the Mo-W mineralisation of East Kounrad deposit. Mineralised zones at East Kounrad mainly trend at 275 to 285° and 330 to 340° with lengths of 8 km and 4 km, respectively. A zonation of mineralisation has been described. The 'ore-shoot' zone is exposed at surface occurring as quartz veins and quartz-mica greisen containing intense molybdenum mineralisation (Bol'shakov, 1965; Chen et al., 2015). The 'below-oreshoot' zone outcrops on the eastern side of the deposit and is characterised by quartz-albite greisen, in which quartz veins contain very weak molybdenum mineralisation, while in the 'above-oreshoot' zone to the west, greisen accompanies thin quartz veins enriched in mica with mionor wolframite (Bol'shakov, 1965; Chen et al., 2015). The W-Mo mineralisation is dominated by quartz veins and veinlets, which mainly occur in the endo- and exo-contact zones of medium- and fine-grained granites, with minor in greisens surrounding quartz veins (Burmistrov et al., 1990; Chen et al., 2015). The mineralised quartz veins average 13 mm in thickness, and are regarded as being typical of veins from porphyry deposits (Li et al., 2016). They are uniformly steeply dipping and are predominantly composed of quartz–K feldspar ± molybdenite, quartz-molybdenite veins and fissures with smears of molybdenite. Molybdenite and wolframite are the main minerals of economic significance at East Kounrad (Chen et al., 2010; Shen et al., 2013). Additional common metallic minerals include pyrite, chalcopyrite, magnetite, hematite, rutile, scheelite, sphalerite, bismuthinite, powellite (Bol'shakov, 1965; Chen et al., 2015; Li et al., 2016).
Both the primary magma and hydrothermal fluids of the East Kounrad deposit are characterised by high fluorine and high oxygen fugacity, which Cao et al. (2018) regard as important for the formation of large, high-grade Mo deposits. Four stages of mineralisation have been identified by Cao et al. (2018), as follows:
• Stage I quartz–wolframite ±molybdenite ±fluorite veins, associated with intensively greisen alteration,formed from fluids with high temperature (340 to 460°C), high pressure (250 to 400 bars), high/low salinity (54.5 wt.% and 3.4 to 10.2 wt.%, respectively), and high oxygen fugacity with a fluid system of H2O-NaCl-CO2.
•Stage II quartz-molybdenite ±pyrite veins, which were accompanied by K feldspars-muscovite-fluorite alteration, formed from fluids with medium-high temperature (260 to 400°C), medium pressure (100 to 250 bars), high/low salinity (39.1 to 58.4 wt.% and 2.4 to 11.7 wt.%, respectively), and relatively low oxygen fugacity. Following this main stage of W and Mo mineralisation,
• Stage III quartz-pyrite ±molybdenite veins, with associated quartz–sericite alteration, were formed from fluids at a medium to low temperature (160 to 340°C), low pressure (<100 bars), a variety of salinities (4.5 to 46.2 wt.%) and high oxygen fugacity.
• Stage IV quartz–polymetallic sulphide veins related to argillic alteration, were formed under temperature of 120 to 220°C and salinity of 1.7 to 8.1 wt.%.
Fluid boiling is regarded as the most important factor in the precipitation mechanism of molybdenite and wolframite, as well as the decreasing oxygen fugacity and temperature which also played a vital role in triggering deposition of molybdenite.
The most recent source geological information used to prepare this decription was dated: 2018.
Record last updated: 16/9/2021
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.
Konyrat
|
|
|
|
Cao, C., Shen, P., Pan, H., Li, C. and Seitmuratova, E., 2018 - Fluid evolution and mineralization mechanism of the East Kounrad porphyry Mo-W deposit in the Balkhash metallogenic belt, Central Kazakhstan: in J. of Asian Earth Sciences v.165, pp. 175-191.
|
Chen X H, Qu W J, Han S Q, Seitmuratova E, Yang N, Chen Z L, Zeng F G, Du A D and Wang Z H, 2010 - Re-Os geochronology of Cu and W-Mo deposits in the Balkhash metallogenic belt, Kazakhstan and its geological significance: in Geoscience Frontiers v.1 pp. 115-124
|
Chen, X., Wang, Z., Chen, Z., Seitmuratova, E., Han, S., Zhou, Q. and Ye, B., 2015 - SHRIMP U-Pb, Ar-Ar and fission-track geochronology of W-Mo deposits in the Balkhash Metallogenic Belt (Kazakhstan), Central Asia, and the geological implications: in J. of Asian Earth Sciences v.110, pp. 19-32.
|
Gao, J., Klemd, R., Zhu, M., Wang, X., Li, J., Wan, B., Xiao, W., Zeng, Q., Shen, PO., Sun J., Qin, K. and Campos, E., 2017 - Large-scale porphyry-type mineralization in the Central Asian metallogenic domain: A review: in J. of Asian Earth Sciences Available on-line from October 18, 2017, 30p.
|
Kudryavtsev Yu K 1996 - The Cu-Mo deposits of Central Kazakhstan: in Shatov, Seltmann, Kremenetsky, Lehmann, Popov and Ermolov (Eds.) Granite-Related Ore Deposits of Central Kazakhstan and Adjacent Areas INTAS-93-1783 Project, St. Petersburg, 1996 pp 119-145
|
Li, C., Shen, P., Pan, H. and Seitmuratova, E., 2019 - Control on the size of porphyry copper reserves in the North Balkhash-West Junggar Metallogenic Belt: in Lithos v.328-329, pp. 244-261.
|
Li, G.-M., Cao, M.-J., Qin, K.-Z., Evans, N.J., Hollings, P. and Seitmuratova, E.Y., 2016 - Geochronology, petrogenesis and tectonic settings of pre- and syn-ore granites from the W-Mo deposits (East Kounrad, Zhanet and Akshatau), Central Kazakhstan: in Lithos vols.252-253, pp. 16-31.
|
Li, G.-M., Cao, M.-J., Qin, K.-Z., Hollings, P., Evans N.J. and Seitmuratova, E.Y., 2016 - Petrogenesis of ore-forming and pre/post-ore granitoids from the Kounrad, Borly and Sayak porphyry/skarn Cu deposits, Central Kazakhstan: in Gondwana Research v.37, pp. 408-425.
|
Seltmann R and Porter T M, 2005 - The Porphyry Cu-Au/Mo Deposits of Central Eurasia: 1. Tectonic, Geologic & Metallogenic Setting and Significant Deposits: in Porter, T.M. (Ed), 2005 Super Porphyry Copper & Gold Deposits - A Global Perspective, PGC Publishing, Adelaide, v.2 pp. 467-512
|
Seltmann, R., Dolgopolova, A. and CERCAMS team, 2012 - Porphyry Cu-Au/Mo Deposits of Central Eurasia: Geodynamics and Metallogeny: in Existing Resources, New Horizons, KazGeo 2012, Almaty, Kazakhstan, 29-31 October 2012, Conference Proceedings, 4p.
|
Seltmann, R., Porter, T.M. and Pirajno, F., 2014 - Geodynamics and metallogeny of the central Eurasian porphyry and related epithermal mineral systems: A review: in J. of Asian Earth Sciences, v.79, pp. 810-841.
|
Shen, P., Pan, H., Hattori, K., Cooke, D.R. and Seitmuratova, E., 2018 - Large Paleozoic and Mesozoic porphyry deposits in the Central Asian Orogenic Belt: Geodynamic settings, magmatic sources, and genetic models: in Gondwana Research v.58, pp. 161-194.
|
Shen, P., Pan, H.D. and Seitmuratova, E., 2017 - Petrogenesis of the mineralized granitoids from the Kounrad and Borly porphyry Cu deposits and the East Kounrad porphyry Mo deposit in Kazakhstan: Implication for tectonic evolution and mineralization of western part of Central Asian Orogenic Belt: in Lithos v.286-287 pp. 53-74.
|
Yakubchuk, A., Degtyarev, K., Maslennikov, V., Wurst, A., Stekhin, A. and Lobanov, K., 2012 - Tectonomagmatic Settings, Architecture, and Metallogeny of the Central Asian Copper Province: in Hedenquist J W, Harris M and Camus F, 2012 Geology and Genesis of Major Copper Deposits and Districts of the World - A tribute to Richard H Sillitoe, Society of Economic Geologists Special Publication 16, pp. 403-432
|
Zvezdov V S, Migachev I F and Girfanov M M 1993 - Porphyry copper deposits of the CIS and the models of their formation: in Ore Geology Reviews v7 pp 511-549
|
|
Porter GeoConsultancy Pty Ltd (PorterGeo) provides access to this database at no charge. It is largely based on scientific papers and reports in the public domain, and was current when the sources consulted were published. While PorterGeo endeavour to ensure the information was accurate at the time of compilation and subsequent updating, PorterGeo, its employees and servants: i). do not warrant, or make any representation regarding the use, or results of the use of the information contained herein as to its correctness, accuracy, currency, or otherwise; and ii). expressly disclaim all liability or responsibility to any person using the information or conclusions contained herein.
|
Top | Search Again | PGC Home | Terms & Conditions
|
|
