Yakutia Diamonds - Mirny, Mir, International, Aikhal, Jubileynaya, Udachny, Nyurba, Verkhne-Munskoye
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Major diamond deposits are exploited over the north-esatern section of the largely concealed Yakutia Archaean Craton, which is exposed through younger Siberian Platform cover as the Anabar and Aldan Shields to the north and south respectively, in eastern Siberia. There ar etwo groups of kimberlites, namely the diamondiferous varieties which are over Archaean-Proterozic basement and non-diamondiferous, younger, pipes on the margins of the platform. The diamondiferous pipes are found cutting platformal sequences overlying a crystalline basement which is at a depth of around 4 km, which decreases to the north.
A series of diamond mining divisions of Almazy Rossii-Sakha Joint Stock Co. Ltd. (ALROSA), exploit both kimberlite and alluvial deposits in the Yakutia region, in the Sakha Republic of Siberia, as follows:
Mirny Division in the Malaya - Botuobiya (or Mirny) Field, which comprises the mines on the now exhausted Mir pipe and the Internationalnaya (18 km WSW of Mir) pipe (#Location; Mir - 62° 31' 36"N, 113° 59' 35"E).
The grade at Mir varied from as high as 400 carats per hundred tonnes (cpht) to as low as 0.05 cpht, but averaged approximately 60 cpht of which around 25% were gem quality. Mir was the first of the main Siberian mines. The pipe was discovered in early 1955 and had a diameter of approximately 800 m and covered and area of some 7 ha, intruding Ordovician limestones. It had an oval shape at surface, and comprised a downward tapering conical shaped pipe that dipped at 75 to 90° to a depth of 300 m. The cross-sectional area of the pipe rapidly decreases below that to 900 m depth where it evolves into a dyke. The kimberlite formed as the result of three phases of intrusion, although the rocks of the different phases do not show significant variation in their physical and mechanical properties or diamond grade. However, there are a variety of kimberlite types characterised by different quantities of xenoliths of country rock, which decrease with depth. Crystalline schist and deep seated xenoliths are rare. Eclogites are subordinate to pyrope bearing ultramafics (lherzolites accompanied by websterites and harzburgites predominating). Petroleum, bitumen and gas occurrences are associated with highly porous layers within the intruded carbonate strata and, to a lesser degree in the kimberlite, resulting in a 'hazardous' categorisation for the mine.
The Internationalnaya (or International) pipe is small but very high grade. The pipe is funnel-shaped down to a depth of 125 m, below which it evolves into a near cylindrical body dipping steeply to the SE. It is composed of autolith kimberlite breccia and porphyritic kimberlite. Both lithologies are similar in terms of diamond grade, although the average grade is slightly higher in the porphyritic kimberlite. The average diamond grade decreases with depth.
The Solur-Vostochnaya placer deposit comprises two spatially separated buried deposits, the Solur and the Vostochnaya, located 25 km NW of Mirny, between the Irelyakh and Chuonalyr Rivers. The Vostochnaya deposit is proluvial in origin and is to be mined over a distance of 4.6 km. The economic layer varies from 0.1 to 1.9 m and averages 0.68 m in thickness. The Solur deposit is diluvial-proluvial with a thickness ranging from 0.5 to 5.1 m, averaging 2.35 m. The thickness of overburden above the Vostochnaya deposit varies from 12 to 58 m, with an average of 47.7 m, whilst the Solur deposit is overlain by 5 to 54 m, averaging 41.7 m.
Aikhal Division in the Alakit Field, which includes the Aikhal, Jubileynaya (13 km NW of Aikhal), Sytykanskaya (30 km to the NNE of Aikhal) and Komsomalskaya (14 km to the NE of Aikhal) kimberlite deposits (#Location; Aikhal - 65° 55' 34"N, 111° 29' 42"E).
This field is some 485 km north to NNW of Mirny. The Jubileynaya (or Jubilee) pipe is large by Siberian standards and is to be mined by open cut. It is close to a classical funnel-shaped pipe with a well-preserved conical mouth in the upper levels. The internal structure of the pipe is complex due to the multiphase intrusion of kimberlites. The pipe is composed of three ore shoots, the central, western and eastern.
The Aikhal pipe intrudes Lower Palaeozoic carbonate rocks, the main part of which is overlain by Upper Palaeozoic terrigenous formations encased within trap basaltic rocks. In occurs is an inclined dyke composed of three ore shoots, each having its own feeder.
The Komsomolskaya kimberlite pipe is a dyke-shaped ore body with a north-easterly orientation. It is intruded by a dolerite dyke that separates two major blocks from the main ore body. The pipe is composed of autolith kimberlite breccia and porphyritic kimberlite differing in their textural and structural properties, material compositions and mineral grade. The central part of the diatreme (the central ore shoot) is a typical volcanic pipe decreasing in width with depth and comprised of autolith kimberlite breccia. The eastern and western flanks of the pipe (dyke-shaped parts of the body) are both composed of porphyritic kimberlite.
Udachny Division in the Daldyn Field which includes the Udachny operation and the Zarnista (12 km east of Udachny), Yakutskaya, Leningradskaya and Dalnaya pipes (#Location; Udachny - 66° 26' 4"N, 112° 19' 2"E).
This field is immediately to the north-east of, and overlaps with the Alakit Field. The kimberlites of the Alakit and Daldyn fields have been dated at 345 and 390 Ma (Devonian to lower Carboniferous). The Udachny (or Udachnaya) pipe was discovered in 1955 and can be traced as a consistent ore body to a depth of 250 m, below which it divides into two adjacent pipes, Udachnaya East and Udachnaya West, separated by a block of Upper Cambrian sedimentary rocks. The pipes are composed respectively of massive kimberlite with fresh olivine, and kimberlite breccia with more abundant xenoliths of mainly crystalline schists, including plagioclase bearing eclogite rich rocks. Both pipes contain xenoliths xenoliths of pseudo-porphyritic, pyrope peridotite. The country rock is lower Ordovician limestones. In 1999 Udachny and Zarnista accounted for around 80% of Russian diamond production.
Anabar Division which exploits alluvial/placer diamond deposits in the Ebelyakh River and the Gusiny Stream in an area some 300 to 400 km to the north to NNW of the Alakit Field and 115 km south of the local administrative centre of Saskylakh, Anabarsky National (Dolgano-Nenets) Ulus (District). Kimberlite pipes within the Anabar division have been dated at between 195 and 245 Ma (early Triassic to early Jurassic).
The Ebelyakh River placer deposit forms a large accumulation with a commercial envelope comprising river bed sediments, lower and upper plains, four terraces above the flood plains and re-deposited parts of the weathered surface layers. The length of the commercial portion of the placer is 82 km. The width varies between 50 and 345 m, with an average width of 78.6 m.
The Gusiny Stream placer is alluvial in origin. Within the valley, the economic diamond content is found in the Upper Quaternary and Neogenic to Lower Quaternary sediments and re-deposited weathered surface layers. The commercial part of the deposit extends over a distance of 8.7 km, with a width that varies from 41.7 to 261.8 m, averaging 128.1 m.
Nyurba Division which includes the new Nakynskoye ore field and the Nyurbinsk, Botuobinskaya (or Botubinsk) and Maiskoye pipes which are 300 km north-east of Mirny and 300 km south-east of Aikhal (#Location; Nyurba - 65° 1' 31"N, 117° 4' 56"E).
The Nyurbinskaya and Botuobinskaya pipes are hosted within a stratigraphic sequence that includes Upper Cambrian and Lower Ordovician rocks that host the kimberlite bodies, as well as overlying Triassic, Lower and Middle Jurassic sedimentary rocks.
The Nyurbinskaya pipe trends north-eastwards, and in plan view has an rounded-ellipsoidal shape. The cross-sectional area of the pipe decreases significantly with depth and, at 280 m to 320 m below surface, it separates into two ore bodies divided by a basite intrusion. Three kimberlite varieties have been detected within the pipe, namely, autolith kimberlite breccias, kimberlite breccias and porphyritic kimberlite. The main part of the pipe is composed of autolith kimberlite breccia and kimberlite breccia, whereas porphyritic kimberlites are traced at deeper levels. The Nyurbinskaya placer deposit is located close to the Nyurbinskaya kimberlite pipe which is the source of the diamond-bearing material.
The Botuobinskaya pipe is located ~3 km SW of the Nyurbinskaya pipe. It has an irregular, elongated shape and gradually tapers out at depth. The first phase of intrusion is represented by porphyritic kimberlite, whilst autolith kimberlite breccias, kimberlite breccias and kimberlite tuff-breccias represent the second phase. The Botuobinskaya placer deposit is closely associated with the kimberlite pipe and adjoins it on the south-western flank.
Verkhne-Munskoye - (#Location; 68° 34' 21"N, 112° 24' 2"E) the Verkhne-Munskoye operation is located near Olenyok, ~225 km north of Udachny, and is one of the largest diamond mines in Russia. It consists of four kimberlite pipes, Zapolyarnaya, Deimos, Novinka and Komsomolskaya-Magnitnaya, and has 64.082 Mt of commercial ore reserves, comprising 38 million carats of diamonds @ 0.6 carats per tonne (ALROSA, 2012), and an annual production capacity of 1.8 million carats. The diamonds from these pipes are distinct by their very high quality.
There are over 1000 known kimberlite pipes and dykes on the Siberian Platform in 20 fields, with at least 150 containing diamonds, although only those listed above have been, or are planed to be mined in the four kimberlite fields and one alluvial district.
Production, Reserves and Resources
The annual production capacity is 12 million carats. The actual company's production was valued at USD1.623 billion in 2000. Russian production in 1999 (almost 100% ALROSA) amounted to around 11.5 million carats of each of gem and industrial diamonds.
JORC compliant remaining resources at ALROSA diamond mines as of 1 July 2013 were (Independent experts report to ALROSA by Micon International, 2013):
Indicated resource - 29.211 Mt @ 3.55 c/t, for 103 782 Kct,
Inferred resource - 10.913 Mt @ 3.11 c/t, for 33 940 Kct,
Indicated resource - 4.208 Mt @ 8.73 c/t, for 36 739 Kct,
Inferred resource - 1.542 Mt @ 7.98 c/t, for 12 304 Kct,
Indicated resource - 7.527 Mt @ 0.78 c/t, for 5903 Kct,
Inferred resource - 1.198 Mt @ 0.72 c/t, for 865 Kct,
Indicated resource - 129.017 Mt @ 0.84 c/t, for 108 166 Kct,
Inferred resource - 65.977 Mt @ 0.62 c/t, for 40 594 Kct,
Potential additional resource - 8.431 Mt @ 0.32 c/t, for 2734 Kct,
Indicated resource - 7.729 Mt @ 4.68 c/t, for 36 159 Kct,
Inferred resource - 8.269 Mt @ 3.87 c/t, for 31 967 Kct,
Indicated resource - 4.812 Mt @ 0.38 c/t, for 1808 Kct,
Udachnaya Pipe ore stockpile Measured resource
Measured resource - 4820 Mt @ 1.52 c/t, for 7329 Kct,
Udachnaya Pipe (underground)
Indicated resource - 75.265 Mt @ 1.50 c/t, for 112 782 Kct,
Inferred resource - 78.305 Mt @ 1.25 c/t, for 98 157 Kct,
Udachnaya Pipe (open pit)
Indicated resource - 3.785 Mt @ 1.19 c/t, for 4501 Kct,
Udachnaya Pipe (open pit)
Indicated resource - 3.785 Mt @ 1.19 c/t, for 4501 Kct,
Udachnaya Remnants (underground remnants above -280 m)
Indicated resource - 3.247 Mt @ 1.54 c/t, for 4995 Kct,
Indicated resource - 58.554 Mt @ 0.21 c/t, for 12 007 Kct,
Indicated resource - 12.264 Mt @ 4.13 c/t, for 50 661 Kct,
Inferred resource - 1.192 Mt @ 5.42 c/t, for 6465 Kct,
Indicated resource - 13.679 Mt @ 5.19 c/t, for 71 044 Kct,
Inferred resource - 2.685 Mt @ 5.14 c/t, for 13 790 Kct,
Maiskoye Kimberlite Body
Inferred resource - 3.841 Mt @ 2.86 c/t, for 10 996 Kct,
Indicated resource - 6.176 Mt @ 1.91 c/t, for 11 814 Kct,
Inferred resource - 6.407 Mt @ 1.66 c/t, for 10 638 Kct,
Inferred resource - 1.085 Mt @ 0.49 c/t, for 537 Kct,
Ebelyakh and Gusiny Stream Placers
Probable reserve - 36.319 Mt @ 0.74 c/t, for 26 749 Kct.
This summary is drawn from references listed below and from "Bartlett, S., Lattanzi, C., Spooner, J., Dodds-Smith, M., Khoudine, M., Pilcher, B.E., Turner, J., Forét, B. and Mahé S., 2013 - Independent expert report on reserves and resources of the diamond assets of the ALROSA Group of companies; Prepared by Micon International Co Limited for the ALROASA Group, 25p."
The most recent source geological information used to prepare this summary was dated: 2013.
Record last updated: 7/2/2016
This description is a summary from published sources, the chief of which are listed below.
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Anand M, Taylor L A, Misra K C, Carlson W D and Sobolev N V 2004 - Nature of diamonds in Yakutian eclogites: views from eclogite tomography and mineral inclusions in diamonds: in Lithos v77 pp 333-348|
Gunther M and Jagoutz E 1997 - The meaning of Sm/Nd apparent ages from kimberlite-derived, coarse grained low temperature garnet peridotites from Yakutia: in Proc. 6th International Kimberlite Conference, Volume 1 - Kimberlites, related rocks and mantle xenoliths Russian Geology and Geophysics, Spec. Issue, Alberton Press, New York v38, no. 1 pp 229-239|
Kinny P D, Griffin B J, Heaman L M, Brakhfogel F F and Spetsius Z V 1997 - Shrimp U-Pb ages of perovskite from Yakutian kimberlites: in Proc. 6th International Kimberlite Conference, Volume 1 - Kimberlites, related rocks and mantle xenoliths Russian Geology and Geophysics, Spec. Issue, Alberton Press, New York v38, no. 1 pp 97-105|
Maas R, Kamenetsky M B, Sobolev A V, Kamenetsky V S and Sobolev N V, 2005 - Sr, Nd, and Pb isotope evidence for a mantle origin of alkali chlorides and carbonates in the Udachnaya kimberlite, Siberia: in Geology v33 pp 549–552|
Moralev V M and Glukhovsky M Z, 2000 - Diamond-bearing kimberlite fields of the Siberian Craton and the Early Precambrian geodynamics : in Ore Geology Reviews v17 pp 141-153|
Roden M F, Patino-Douce A E, Jagoutz E and Lazko E E. 2006 - High pressure petrogenesis of Mg-rich garnet pyroxenites from Mir kimberlite, Russia: in Lithos v90 pp 77-91|
Seltmann, R., Soloviev, R., Shatov, V., Pirajno, F., Naumov, E. and Cherkasov, S., 2010 - Metallogeny of Siberia: tectonic, geologic and metallogenic settings of selected significant deposits: in Australian J. of Earth Sciences v.57, pp. 655-706.|
Shimizu N, Pokhilenko N P, Boyd F R and Pearson D G 1997 - Geochemical characteristics of mantle xenoliths from the Udachnaya kimberlite pipe: in Proc. 6th International Kimberlite Conference, Volume 1 - Kimberlites, related rocks and mantle xenoliths Russian Geology and Geophysics, Spec. Issue, Alberton Press, New York v38, no. 1 pp 205-217|
Sobolev N V, Logvinova A M, Zedgenizov D A, Seryotkin Y V, Yefimova E S, Floss C and Taylor L A 2004 - Mineral inclusions in microdiamonds and macrodiamonds from kimberlites of Yakutia: a comparative study: in Lithos v77 pp 225-242|
Sobolev V N, Taylor L A, Snyder G A, Sobolev N V, Pokhilenko N P and Kharkiv A D 1997 - A unique metsomatized peridotite xenolith from the Mir kimberlite, Siberian Platform: in Proc. 6th International Kimberlite Conference, Volume 1 - Kimberlites, related rocks and mantle xenoliths Russian Geology and Geophysics, Spec. Issue, Alberton Press, New York v38, no. 1 pp 218-228|
Solovjeva L V, Egorov K N, Markova M E, Kharkiv A D, Popolitov K E and Barankevich V G 1997 - Mantle metasomatism and melting in mantle-derived xenoliths from the Udachnaya kimberlite; Their possible relationship with diamond and kimberlite formation: in Proc. 6th International Kimberlite Conference, Volume 1 - Kimberlites, related rocks and mantle xenoliths Russian Geology and Geophysics, Spec. Issue, Alberton Press, New York v38, no. 1 pp 182-204|
Spetsius Z V and Griffin W L 1997 - Trace elements in minerals from eclogites from the Udachnaya kimberlite pipe: in Proc. 6th International Kimberlite Conference, Volume 1 - Kimberlites, related rocks and mantle xenoliths Russian Geology and Geophysics, Spec. Issue, Alberton Press, New York v38, no. 1 pp 240-246|
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