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Verninskoye |
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Siberia, Russia |
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Au Ag
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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 Verninskoye gold deposit is located 6 km NE of the settlement of Kropotkin, ~130 km NE of the town of Bodaybo, and 1030 km NE of Irkutsk in Siberia, Russia (#Location: 58° 32' 19"N, 115° 21' 57"E).
The Verninskoye deposit is situated near the centre of the Lena Gold Province, at the boundary between the Siberian Platform and the Baykal-Patomsk fold belt. The Lena Gold Province has produced >2000 t of gold from rich gold placer deposits operated since the middle of the 19th century, but also includes the Sukhoi Log and other hard rock gold deposit such as Vysochaishee and Chertovo Koryto in the Bodaybo area.
Two main types of hard rock gold mineralisation are found in the Lena Gold Province, i). quartz veins and ii). quartz-sulphide vein and disseminated deposits, both of which are structurally controlled. These deposits are localised within the Bodaybinskiy Synclinorium which folds greenschist facies Neoproterozoic metasedimentary rocks that are deformed into a series of tight synclines and anticlines. Verninskoye is localised within the Marakano-Tungusskaya Syncline, a high order structure within the broader synclinorium. The Central part on this syncline is composed of sedimentary rocks of the Neoproterozoic Patomskaya Series, the oldest black shale unit of the Baikal-Patom region. It consists of thick layers of black shale, siltstone and limestone, interbedded in varying proportions. These rocks have been folded into a moderately inclined, tight antiform with asymmetric south vergence. The axial planes of folding trends ~WNW and dips at 30 to 40°NNE. A slaty and axial planar cleavage has been developed in less competent and altered rocks, and faults and breccias have offset stratigraphy.
The Verninskoye mineralisation is controlled by a series of shear zones related to a combination of north and NNE dipping fold and fault structures. It occurs at the contact between the black shale and siltstone-limestone units on the limbs and crest of a moderately inclined, tightly folded, asymmetric antiform. More widespread stockwork mineralisation occurs within the mixed sedimentary units. Gold is found in quartz-sulphide veins and in association with disseminated pyrite and arsenopyrite with minor pyrrhotite, chalcopyrite, sphalerite and galena. Sheeted and stockwork quartz-carbonate vein and disseminated mineralisation are found both sub-parallel to, and crosscutting bedding, with the local siliceous and sericite alteration apparently overprinting primary sedimentary structures.
Most gold at Verninskoye occurs as <100µm free particles with minor courser gold. The amount of sulphide within the black shale increases towards the limestone contact, comprising as much as 10 to 15% of the rock by volume, where it forms the highest grade mineralised zones. Some course visible gold occurs in quartz veins associated with pyrite and arsenopyrite. Gold mineralisation is best developed within the pit where it occurs in the upward facing limb of the fold, occurring adjacent to the upper contact of the limestone, but is also more weakly developed at the same contact on the downward facing limb of the tight anticlinal fold. Mineralisation, as defined by the limits of low grade stockworking, and is found over an area of 1500 m along, and 1100 m across strike, and persists to a depth of at least 740 m. The complex nature of the mineralisation and the gradational contacts of mineralised zones, results in their interpreted thickness varying widely from metres to tens of metres. Oxidation is restricted to the top 5 to 10 m below the surface.
Remaining JORC compliant Ore Reserves and Mineral Resources at 31 December 2017 were (Polyus Ore Reserves and Mineral Resources Update 20 March, 2018):
Proved + Probable Ore Reserves - 94 Mt @ 1.7 g/t Au for 160 t of contained gold;
Measured Mineral Resources - 12 Mt @ 1.3 g/t Au;
Indicateded Mineral Resources - 209 Mt @ 1.6 g/t Au;
Inferred Mineral Resources - 14 Mt @ 2.0 g/t Au;
TOTAL Mineral Resources - 235 Mt @ 1.6 g/t Au for 376 t of contained gold;
Production in 2016 amounted to 12.9 Mt of waste, 3.4 Mt of ore and 7.47 t of gold.
Details in this summary are drawn from the Competant Person's Report - Mineral Assets PJSC Polyus, prepared by AMC Consultants Pty Ltd, Perth, Western Australia, dated 5 June 2017.
The most recent source geological information used to prepare this decription was dated: 2017.
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.
Verninskoye
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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.
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