The native gold extracted in the Amur Region for 150 years

2021 ◽  
pp. 57-62
Author(s):  
ANTON MELNIKOV ◽  
VALENTINE MOISEENKO ◽  
VITALY STEPANOV
Keyword(s):  
Native Gold ◽  
Amur Region ◽  
Gold Production ◽  
Sample Distribution ◽  
Placer Gold ◽  
Porphyry Deposits ◽  
Percentage Points ◽  
Gold Silver ◽  
Production History ◽  
Gold Sulfide

Data on gold production history and typomorphic features of native gold from the Amur province are provided. It is shown that about 1,116 t of primarily placer gold was extracted for 150 years, with primary gold accounting for 23,8 %. Placer gold sample distribution is unimodal with a maximum ranging within 850–925 ‰. Mercury prevails in microimpurities, its content in some clusters reaches the first percentage points. In terms of composition impurities, placer gold corresponds to gold from fields and occurences of gold-quartz and gold-sulfide-quartz formations. Low-fineness gold, (799–700 ‰) less common in placers, resulted from destruction of gold-silver unit sources while that of average fineness (800–900 ‰) was a result of the same process related to gold-polymetallic and gold-sulfide units. Gold-copper-molybdenum porphyry deposits do not form placers. The prospects of primary and placer gold production in the Amur region are defined.

scholarly journals DISCOVERY AND STUDY HISTORY POKROVSKY GOLD ORE DEPOSIT IN THE AMUR REGION

2020 ◽  
pp. 63-72
Author(s):  
ANTON VLADIMIROVICH MELNIKOV ◽  
◽  
VITALY ALEKSEEVICH STEPANOV ◽  
DMITRIY VALERYEVICH YUSUPOV ◽  
◽  
...  
Keyword(s):  
Native Gold ◽  
Amur Region ◽  
Near Surface ◽  
Ore Deposit ◽  
Gold Ore ◽  
Gold Silver ◽  
History Of ◽  
Typical Composition ◽  
Gold Ore Deposit

A brief history of the discovery and study of the large Pokrovsky gold ore deposit of the Amur Region, from the ores of which about 63 tons of gold were extracted, is given. The role of scientific and production organizations and individual geologists in the discovery of the deposit is shown. According to the results of almost half a century of research, the deposit is classified as a near-surface gold-silver formation with a typical composition of ores, near-ore metasomatites and native gold for deposits of this type. The closest analogue of Pokrovka is the Kubak deposit of the Omolonsky gold-silver province.

scholarly journals The Lode Gold Occurrence in the «Territory» of Oleg Kuvaev (North of the Chukotka Upland)

2021 ◽  
Vol 20 (3) ◽  
pp. 250-266
Author(s):  
V.I. Silaev ◽  
◽  
A.V. Kokin ◽  
V.N. Filippov ◽  
A.F. Khazov ◽  
...  
Keyword(s):  
Quartz Vein ◽  
Native Gold ◽  
Gold Deposits ◽  
Lode Gold ◽  
Carbon Particles ◽  
The North ◽  
Aluminium Sulfate ◽  
Gold Silver ◽  
Lode Gold Deposits ◽  
Gold Sulfide

A sample of a gold-bearing quartz vein from the Upper-Ichuveem ore occurrence, discovered in the Triassic terrigenous complex in the north of the Chukotka Upland, the Oleg Kuvaev's “Territory”, had been comprehensively studied. The gross gold grade was estimated at 3–4 g / t. The vein includes quartz, native gold, sulfide-goldsilver solid solutions, alumoseladonite, aluminium-sulfate-phosphates Fe-Pb-Mg-Ca compound, apatite, pyrite, iron-titanium oxides, litharge, native phases composed of Fe (Ni), Ag-Pb-Bi, Fe-Al-PS-As, multicomponent ocher of hypergene origin. Native gold ranges from medium to fine. The vein contains particles of non-crystalline organic matter, which is close in composition of organic groups to polysaccharides. It is possible that the carbon particles found in the gold-quartz vein are of an abiogenic nature and can be compared with abiogenic condensed organelles in the products of modern volcanism. The data obtained make it possible to attribute the Upper- Ichuveem gold ore occurrence to a low-sulfide gold-quartz formation, but with additional signs of gold-silver and polymetallic formations, which can be regarded as a favorable prerequisite for prospecting and exploration in Oleg Kuvaev's «Territory» not only of gold-placer deposits, but also of lode gold deposits.

scholarly journals Mineralogical features of gold of the Permian conglomerates of the Sololiy uplift of the Olenek high (Northeastern Siberian platform)

2021 ◽  
Vol 66 (3) ◽  
Author(s):  
Boris B. Gerasimov ◽  
◽  
Roman Yu. Zhelonkin ◽  
Makhmutyan G. Mukhamedyarov ◽  
◽  
...  
Keyword(s):  
Low Grade ◽  
Mosaic Block ◽  
Placer Gold ◽  
Hydrothermal Mineralization ◽  
Gold Silver ◽  
Ore Mineralization ◽  
Tectonic Zones ◽  
Gold Sulfide ◽  
Primary Medium ◽  
Gold Bearing

Typomorphic features of placer gold of conglomerates of the Ortokinskaya formation of the Early Permian age (P1or) of the Sololiy Uplift of the Olenek High and modern channel alluvium of the Ortoku Eekit river, which drains these deposits, are studied. It is found that extremely heterogeneous composition and complex inner structure are typical features of the vast majority of gold of the Permian conglomerates. There are several stages of different fineness (from 251‰ to 999‰) within a single gold particle, as a result, gold has a mosaic-block inner structure. It is proposed that such heterogeneity is formed due to epigenetic transformations of primary medium-grade gold in an intermediate reservoir of the Permian age, and also under influence of superposed hydrothermal mineralization with low-grade gold, related to the processes of the Mesozoic tectonomagmatic activation. The latter is indicated by the discovery of impregnated gold-sulfide mineralization in the Permian conglomerates. Ore mineralization is represented by gold, silver, pyrite, sphalerite, chalcopyrite, galena, argentite, native tin, and barite. Association mineralization to thin tectonic zones of conglomerate fragmentation, suggests that superposed gold-sulfide hydrothermal mineralization of impregnated type was formed as a result of manifestations of the Mesozoic tectonomagmatic activation, when gold-bearing hydrothermal solutions migrated in faults. It is determined that auriferous conglomerates of the Ortokinskaya formation of the Permian age were major sources of placer gold of modern alluvium in the studied part of the Ortoku Eekit.

scholarly journals The Internal Structure of Placer Gold of the North-East of the Siberian Platform as a Reliable Search Sign of Primary Sources

2021 ◽  
Vol 906 (1) ◽  
pp. 012082
Author(s):  
Boris Gerasimov
Keyword(s):  
Internal Structure ◽  
Siberian Platform ◽  
Native Gold ◽  
Primary Source ◽  
Primary Sources ◽  
Placer Gold ◽  
North East ◽  
The North ◽  
History Of ◽  
Gold Sulfide

Abstract Typomorphic features of placer gold are carriers of the most important information necessary for the reconstruction of the history of the formation of placer and ore occurrences of gold and can be used as mineralogical criteria in the search for primary sources of placers. The study of these features is relevant for placer areas with unidentified gold sources, which include the territory of the north-east of the Siberian Platform. The internal structure of native gold is one of the most informative typomorphic features is. We studied the internal gold structures of modern placers and conglomerates of the Early Permian age in the north-east of the Siberian Platform. The purpose of the work: to identify the features of the internal structure of placer gold, depending on the chemical composition and the degree of its transformations, as well as the possibility of their use as a prospecting indicator. Structural etching of native gold was performed using the reagent: HCl + HNO3 + FeCl3 × 6H2O + CrO3 + thiurea + water. As a result of the research, it was found that the well-rounded high-grade gold of modern placers has undergone repeated redeposition through intermediate sources. The discovery of slightly rounded gold with an internal structure without signs of exogenous transformation indicates that it entered the modern alluvium from a nearby primary source. This was a prerequisite for setting up ore gold exploration, resulting in identification of apocarbonate hydrothermal-metasomatic formations with disseminated gold-sulfide mineralization were identified. Thus, the features of the internal structures of placer gold in combination with other typomorphic features are additional indications of determining the sources of formation of gold-bearing placers.

scholarly journals Typomorphic Features of Placer Gold from the Billyakh Tectonic Melange Zone of the Anabar Shield and Its Potential Ore Sources (Northeastern Siberian Platform)

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 281
Author(s):  
Boris Gerasimov ◽  
Vasily Beryozkin ◽  
Alexander Kravchenko
Keyword(s):  
Native Gold ◽  
Gold Mineralization ◽  
Coarse Fraction ◽  
Gold Deposits ◽  
Primary Sources ◽  
The Arctic ◽  
Geochemical Data ◽  
Placer Gold ◽  
Anabar Shield ◽  
Tectonic Mélange

Precambrian shields and outcropped Precambrian rock complexes in the Arctic may serve as the most important sources of various types of mineral raw materials, including gold. The gold potential of the Anabar shield in the territory of Siberia has, thus far, been poorly studied. A number of primary and placer gold occurrences have been discovered there, but criteria for the prediction of and search for gold mineralization remain unclear. The main purpose of this paper was to study the typomorphic features of placer gold in the central part of the Billyakh tectonic mélange zone in the Anabar shield and to compare them to mineralization from primary sources. To achieve this, we utilized common methods for mineralogical, petrographic, and mineragraphic analyses. Additionally, geochemical data were used. As a result of this investigation, important prospecting guides were identified, and essential criteria for the prediction of and search for gold deposits were elucidated. The characteristics of the studied placer gold were specific for gold derived from a proximal provenance. These characteristics included the poor roundness of the native gold grains, a cloddy–angular and dendritic form, an uneven surface, and a high content of coarse-fraction native gold (0.5–2 mm), which was as high as 24% of the volume of analyzed native gold. In addition, we conducted a study on the mineralogical features of the gold-sulfide mineralization that was disseminated throughout a small exposure area of paleo-Proterozoic para- and orthogneisses in the Anabar shield basement. A comparison of mineral inclusions in the coarse-fraction native gold and mineral assemblages in the ore deposits showed that one of the possible primary sources for placer gold might be small bodies of metasomatically altered orthogneisses associated with large granitoid plutons.

scholarly journals Giant Placers of the Victorian Gold Province

SEG Discovery ◽  
2004 ◽  
pp. 1-18
Author(s):  
Martin J. Hughes ◽  
G. Neil Phillips ◽  
Stephen P. Carey
Keyword(s):  
Late Cretaceous ◽  
Quartz Vein ◽  
Late Eocene ◽  
Gold Deposits ◽  
Gold Production ◽  
Placer Gold ◽  
High Rainfall ◽  
Hydrothermal Quartz ◽  
Alluvial Gold ◽  
Primary Gold

ABSTRACT The Victorian gold province has yielded 2500 tonnes (t) Au, nearly 2 percent of cumulative world gold production, mostly mined between 1851 and 1910. Fifty-five percent (1375 t) was placer gold from modern and paleostream systems, and from eluvial deposits, and the remainder came from primary quartz vein-related deposits. Most of the alluvial gold placers are in unconsolidated or weakly cemented quartz pebble conglomerate and gravel, dominated by hydrothermal quartz, although a few paleoplacers are within duricrusted conglomerate that required crushing. Large and abundant gold nuggets were common. Placer gold deposits formed in three intervals following uplift in the Late Cretaceous, Late Eocene, and Pliocene. An important factor in the preservation of the paleoplacers has been their burial by younger sediments and basalt flows, with consequent protection from erosion and dispersal. Factors in the formation of the giant gold placers of Victoria include the following: (1) the existence of a major primary gold province with several multimillion-ounce gold deposits; (2) uplift and reactivation of older faults; and (3) high rainfall and deep Paleogene weathering.

scholarly journals The Alteration and Mineralization Characteristics of Miocene Porphyry Cu-Au Deposits of Chagai Magmatic Belt, District Chagai, Balochistan, Pakistan

2021 ◽  
Vol 12 (1) ◽  
pp. 1-8
Author(s):  
Fida Murad ◽  
Abdul Ghaffar ◽  
Innayat Ullah ◽  
Abdul Shakoor Mastoi ◽  
Muhammad Tariq Zaman
Keyword(s):  
Hydrothermal Alteration ◽  
Porphyry Copper ◽  
Proximal Part ◽  
Wall Rock ◽  
Mountain Range ◽  
Porphyry Deposits ◽  
Magmatic Arc ◽  
Metallogenic Belt ◽  
Gold Silver ◽  
Ore Mineralization

Subduction related Miocene porphyry type deposits are found in the east-west trending Chagai magmatic belt (CMB) in Pakistan's western margin, Balochistan. This arc exists on the west segment of the Tethyan metallogenic belt in the south-west of Pakistan. Tethyan metallogenic belt is widely spread over 12,000 km from east to west direction from Indochina, Tibet, Pakistan, Iran, Turkey and Alpine mountain range in Europe. During the last thirty to forty years several porphyry deposits have been reported in the Chagai magmatic arc, including the very large Reko Diq H14-H15, large Saindak, Tanjeel, H35, H8 and medium Dasht-e-Kain porphyry deposits and many small porphyry copper deposits. These porphyry deposits were developed within the phase of calc-alkaline type magmatism in the Chagai arc. Tonalite, quartz diorite, and monzonite host the porphyry deposits within the adjacent sedimentary wall rock units of Sinjrani Volcanic Group, Juzzak, Saindak, and Amalaf Formations. The concentric zonal pattern of hydrothermal alteration in these porphyry deposits of the Chagai magmatic arc follows the world's major porphyry deposits' alteration pattern. Zones of hydrothermal alteration from distal to proximal part includesa potassic alteration, sericitic-clay-chlorite alteration, sericitic alteration, argillic alteration and propylitic alteration. Major ore mineralization in these deposits is of copper, gold, silver, molybdenum, and minor constituents of other base metals that have been reported to occur within hydrothermal alteration zones in the Miocene porphyry Chagai magmatic arc

scholarly journals Native gold in the weathering crust of the Nizhneselemdzhinsky gold-bearing node (Amur region)

LITOSFERA ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 239-255
Author(s):  
I. V. Kuznetsova ◽  
P. P. Safronov
Keyword(s):  
River Basin ◽  
Noble Metal ◽  
Native Gold ◽  
Gold Deposits ◽  
Amur Region ◽  
Weathering Crust ◽  
Resource Base ◽  
Long Acting ◽  
Host Rocks ◽  
Gold Bearing

Research subject. The weathering crust of Proterozoic slates in the Neklya River basin and Paleozoic granites in the Nizh- neselemdzhinsky gold-bearing node (NGBN) in the Tatarka River basin.Methods. The research was carried out using the methods of atomic absorption, X-ray fluorescent and mineralogical analysis of rocks and minerals. The method of raster electron microscopy was used to study the element structure, morphological and microstructural features of minerals.Results. Specific features of native gold from the weathering crust of NGBK were defined. It was established that the NGBN weathering crust contains both hypogene gold, partially changed in the course of hypergenesis, and neogenic gold. A considerable share of gold is of high purity (1000%o). Occasionally, gold in the form of complex accretions from grains of different morphology and structure is present. A specific feature of weathering crust gold is its interpenetrations within the rock matrix of a varying mineral structure. Gold-bearing carbonaceous structures in the form of films and outgrowths on gold grains were revealed; the presence of carbon in rock components associating with the noble metal was defined. In the crust, the participation of carbon in physicochemical processes was established, as a result of which the release of Au, encapsulated in minerals-concentrators, and its redeposition on geochemical barriers occur. Gold nanoparticles can be long-acting growth centres in the host rocks, first coalescing with each other to yield nanoformations, then microforms, etc. In the weathering crust of gold deposits, both the transformation of the hypogenic noble metal and the formation of its new forms occur.Conclusion. This work contributes to the expansion of the mineral resource base of gold in the Amur Region, including through such unconventional sources as the NGBN weathering crust.

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