Evolutionary-genetic method for forecasting ore gold objects

The subject of the research is methods for predicting natural heterogeneities containing mineralized areas of the earth’s interior, accumulations of ore gold, which allow obtaining reliable knowledge about a mineral object, applying effective methods for its assessment, study and practical use. The topic of research is an evolutionary-genetic method for predicting ore gold objects, which was used to assess the prospects for gold content in Eastern Transbaikalia on a scale of 1: 500,000 at the beginning of this century. The purpose of the work is to present a new forecasting method, which boils down to identifying geological formations specialized for gold (geoblocks, strata, horizons, zones), and within them - areas of multiple gold concentration. The research methodology consists in identifying the main stages, geological processes leading to the concentration of gold in the process of long-term evolution of natural facies and formations, clarifying the sources of gold and gold-bearing objects in them. As a result of forecasting, it was found that at high initial gold contents in the initial substrate, one or two stages of its mobilization formation and redistribution are sufficient, at low gold contents, multiple redistribution and concentration are required. The likelihood of the industrial and larger-scale gold mineralization is directly correlated with the prospects of geological structures for the localization of endogenous mineralization, conditions that exclude the dispersion of matter in the final phase of ore formation, and the number of concentration stages. The method makes it possible to exclude from the perspective huge areas of the central parts of granite-gneiss domes and granite plutons and requires careful attention to mafic blocks that are not exposed according to geophysical data by erosion, as well as to xenoliths and remnants of potentially gold-bearing host rocks among granitoids

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Predictive geochemistry of ore gold in Eastern Transbaikalia

Transbaikal State University Journal ◽

10.21209/2227-9245-2020-26-10-6-14 ◽

2020 ◽

Vol 26 (10) ◽

pp. 6-14

Author(s):

Yu. Pavlenko ◽

Keyword(s):

Gold Mineralization ◽

Geological Mapping ◽

Earth’S Crust ◽

Natural Environments ◽

Gold Concentration ◽

Gold Ore ◽

Natural Concentration ◽

Eastern Transbaikalia ◽

Earth's Crust ◽

Gold Bearing

The subject of the research is the methods of forecasting the Eastern Transbaikalia - a large mining region of Russia, in which the main internal and external criteria for ore content are established by modern geological mapping at a scale of 1:1,000,000. The article considers endogenous geochemical criteria for gold concentration in the Earth’s crust of the region, which constitute a mandatory methodological method for predicting gold ore objects at any scale. The aim of the work is to clarify the achieved level of knowledge about the mineralogical and geochemical criteria for gold concentration in the course of the evolution of the Earth’s crust up to the formation of industrial deposits and the isolation of ore formations. The methodology of the study is to systematize a huge amount of factual material concerning the processes of natural concentration of gold, to analyze its representativeness, to assess the completeness and reliability of published and stock information used to clarify the mineralogical and geochemical criteria for predicting ore gold. Using the chemical properties of gold, the forms of finding gold, amount of it in the forming geological complexes and natural environments, their evolution, distribution in structural and tectonic zones, some causes of concentration and mineralogical and geochemical prediction criteria are considered. Special attention is paid to the need to study and account for nanoscale (dispersed) gold. As the main ore-formation units of gold mineralization, standardized ore formations are defined with a division into gold ore proper, complex gold-bearing and gold-bearing and geological and industrial types of deposits. There are 15 geological and industrial types, of which 13 are transbaikal deposits standards and two are attracted from other regions. These types of deposits differ in the number of objects related to them. Due to some similarity in the composition of ore matter, geological and industrial types differ in the most important classification characteristics for the forecast. Areas of distribution of direct and indirect mineralogical and geochemical features grouped into mineralogical and geochemical forecast criteria are promising for endogenous concentration of gold mineralization

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Re–Os Pyrite Geochronological Evidence of Three Mineralization Styles within the Jinchang Gold Deposit, Yanji–Dongning Metallogenic Belt, Northeast China

Minerals ◽

10.3390/min8100448 ◽

2018 ◽

Vol 8 (10) ◽

pp. 448 ◽

Cited By ~ 2

Author(s):

Shun-Da Li ◽

Zhi-Gao Wang ◽

Ke-Yong Wang ◽

Wen-Yan Cai ◽

Da-Wei Peng ◽

...

Keyword(s):

Gold Deposit ◽

Northeast China ◽

Gold Mineralization ◽

Metallogenic Belt ◽

Isotopic Analyses ◽

Mantle Sources ◽

Stage 1 ◽

Geochronological Evidence ◽

Gold Bearing

The Jinchang gold deposit is located in the eastern Yanji–Dongning Metallogenic Belt in Northeast China. The orebodies of the deposit are hosted within granite, diorite, and granodiorite, and are associated with gold-mineralized breccia pipes, disseminated gold in ores, and fault-controlled gold-bearing veins. Three paragenetic stages were identified: (1) early quartz–pyrite–arsenopyrite (stage 1); (2) quartz–pyrite–chalcopyrite (stage 2); and (3) late quartz–pyrite–galena–sphalerite (stage 3). Gold is hosted predominantly within pyrite. Pyrite separated from quartz–pyrite–arsenopyrite cement within the breccia-hosted ores (Py1) yield a Re–Os isochron age of 102.9 ± 2.7 Ma (MSWD = 0.17). Pyrite crystals from the quartz–pyrite–chalcopyrite veinlets (Py2) yield a Re–Os isochron age of 102.0 ± 3.4 Ma (MSWD = 0.2). Pyrite separated from quartz–pyrite–galena–sphalerite veins (Py3) yield a Re–Os isochron age of 100.9 ± 3.1 Ma (MSWD = 0.019). Re–Os isotopic analyses of the three types of auriferous pyrite suggest that gold mineralization in the Jinchang Deposit occurred at 105.6–97.8 Ma (includes uncertainty). The initial 187Os/188Os values of the pyrites range between 0.04 and 0.60, suggesting that Os in the pyrite crystals was derived from both crust and mantle sources.

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Gravity-flotation gold-bearing ore concentration

Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy) ◽

10.17073/0021-3438-2021-1-4-15 ◽

2021 ◽

Vol 1 (1) ◽

pp. 4-15

Author(s):

P. K. Fedotov ◽

A. E. Senchenko ◽

K. V. Fedotov ◽

A. E. Burdonov

Keyword(s):

High Performance ◽

Gold Recovery ◽

Gold Content ◽

Flotation Concentrate ◽

Stage Scheme ◽

Study Results ◽

Ore Minerals ◽

Concentrate Yield ◽

Flotation Concentration ◽

Gold Bearing

The paper focuses on the study of the gold-bearing ore dressability. According to technological research, the average gold content is 11.88 g/t. The silver content is insignificant – 2.43 g/t. Main ore minerals in the sample are pyrite and pyrrhotite. According to mineralogical and X-ray structural analysis, the average content of these minerals in the ore is about 6 % (in total). Main rock-forming minerals of the original ore are: quartz (60.1 %), quartz-chlorite-mica aggregates (3.8 %), carbonates (7.1 %). According to the study results, it was found that the gold recovery in the GRG test was 72.75 % with a total concentrate yield of 1.34 % and a content of 664.78 g/t. At the same time, the gold content in tailings was 3.29 g/t. A stage test showed that it is advisable to use a two-stage scheme for ore processing by gravity technology only. The first stage is in the grinding cycle with the 60–70 % ore size, and the second stage is with the final classifier overflow size of 90 % –0.071 mm. Centrifugal separation has high performance as a free gold recovery operation in the grinding cycle. A concentrate with a gold content of 2426 g/t was obtained with a yield of 0.31 % and a recovery of 63.74 %. The beneficiation of first stage tailings ground to 90 % –0.071 mm at the KC-CVD concentrator (modeling) made it possible to extract gold into a total gravity concentrate (KC-MD + KC-CVD) of 87.25 % with a concentrate yield of 22.63 %. The gold content in tailings was 1.97 g/t. The results of gravity and flotation concentration of the original ore indicate the feasibility of using a combined gravity-flotation technological scheme. In a closed experiment of the initial ore beneficiation according to the gravity-flotation scheme at a natural pH of the pulp (without adding acid), the following products were obtained: gravity concentrate with a gold content of 2426 g/t at a yield of 0.31 % and recovery of 64.06 %; flotation concentrate (after the II cleaning) with a gold content of 122 g/t at a yield of 2.90 % and recovery of 33.01 %; the total gold recovery in the gravity-flotation concentrate was 94.07 % with a yield of 3.21 % and an Au content of 345.87 g/t, the gold content in the flotation tailings was 0.72 g/t.

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Geochemistry of Umm Rus gold - quartz veins, Central Eastern Desert Egypt. A new contribution

Bulletin of the Geological Society of Greece ◽

10.12681/bgsg.17174 ◽

2001 ◽

Vol 34 (3) ◽

pp. 1139

Author(s):

O. A. KAMEL ◽

M. M. EL MAHALLAWI ◽

H. M. HELMY

Keyword(s):

Hybrid Zone ◽

Eastern Desert ◽

Quartz Diorite ◽

Low Grade ◽

Gold Content ◽

Strongly Correlated ◽

Quartz Veins ◽

Central Eastern Desert ◽

Pan African ◽

Gold Bearing

Gold-bearing quartz veins of the Umm Rus area occur at the south-eastern contact of a Precambrian granodiorite cupola within younger gabbros of 573-615 Ma belonging to the Pan African orogenic belt. The rocks are intruded within low-grade metasediments. At such contact, a hybrid zone is developed characterized by the occurrence of quartz diorite which grades into diorite and meta-ferrogabro. A limited number of mineralized quartz veins cut the granodiorite-gabbro complex. Different alteration zones are developed in the vicinity of the quartz veins. The quartz veins have two main trends; NS and N30 E, the latter one is usaually gold-bearing. The mineralized parts of the veins commonly consist of highly sheared and banded smoky quartz, and the gold content depends on the relation with the dykes. The element is strongly correlated with As and Ag, but moderately with Cu. Near to intermediate and basic dykes, the contents of Au, Ag and As are noticably increased

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A NEW GOLD ORE REGION IN TANZANIA

Visnyk of Taras Shevchenko National University of Kyiv Geology ◽

10.17721/1728-2713.82.07 ◽

2018 ◽

pp. 55-59

Author(s):

V. Mykhailov ◽

А. Tots

Keyword(s):

Gold Deposit ◽

Shear Zone ◽

Gold Mineralization ◽

Lake Victoria ◽

Gold Deposits ◽

Mobile Belt ◽

Gold Content ◽

Gold Ore ◽

Metallogenic Zone ◽

The Republic

Tanzania is one of the leading gold mining countries in the world and the discovery of new gold resources on its territory is an actual task. Known gold deposits are concentrated mainly in the northwest of the country, in the metallogenic zone of Lake Victoria, where they are associated with the Archean greenstone belts, and to a lesser extent – in the southwest, in the ore regions of Lupa and Mpanda, confined to the Ubendian Paleoproterozoic mobile belt. With regard to the eastern regions of Tanzania, where the Proterozoic structures of the Uzagaran mobile belt are developed, until recently in this region any significant manifestations of gold mineralization were not known. As a result of our research in the northern part of the Morogoro province of the Republic of Tanzania, a new previously unknown gold deposit Mananila was discovered. It is represented by a large volume, up to 400–450 m long, up to 60–80 m thick, mineralized shear zone over intensely leached and schistosed migmatites, gneisses, amphibolites, penetrated by echelon systems of quartz veins and veinlet, steeply dipping bodies of quartz breccia up to 1.0–1.5 m thick. Gold contents range from 0.61 to 8.11 g/t, the average zone content is 2.5–3.0 g/t. Parallel to the main zone, similar structures are developed on the site, although they are of lower thickness. The forecast resources of the deposit are estimated at 20 tons of gold. 2.8 km to the east from the Mananila field, the recently discovered Mazizi gold deposit is located, and a number of small occurrences of gold are also known in the region. All these objects are located within a large shear zone of the northeastern strike, up to 4–5 km width, over 20 km in length. This serves as the basis for the identification of a new gold ore region in the northern part of the Morogoro province of the United Republic of Tanzania, within the Proterozoic mobile belt of Usagaran, the possible gold content of which has never been previously discussed in geological literature.

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Gold Deposits in Chile

Andean geology ◽

10.5027/andgeov48n1-3294 ◽

2021 ◽

Vol 48 (1) ◽

pp. 1

Author(s):

José Cabello

Keyword(s):

Porphyry Copper ◽

Gold Deposits ◽

Ore Deposits ◽

Gold Content ◽

Base Metals ◽

Porphyry Copper Deposits ◽

Copper Deposits ◽

Mineralization Age ◽

Low Sulfidation ◽

Gold Bearing

A review of gold and gold bearing base metals deposits in Chile, indicate the existence of at least six different type of ore deposits, most largely formed during the Cenozoic with predominance in the Miocene. Mesozoic deposits are common but less relevant regarding their size and gold content. These hydrothermal ore deposits are genetically associated with subduction related Andean arc magmatism. Due to its relationship with episodic magmatism migrating eastward, there is a tendency for the deposits to be in distinct, north-south trending, belts with a progressive west to east decrease in mineralization age. After analysing 82 cases in total, main gold concentration can be assigned to high-sulfidation epithermal and porphyry type deposits. Low-sulfidation epithermal, IOCG and mesothermal type appears as less relevant. Gold bearing copper deposits constitute an important part of Chile’s total gold production. Both IOCG type but especially porphyry copper deposits are and will remain as a substantial source to supplement the future output of the gold in the country. The 82 deposits with their tonnage and grade studied, represent a total gold content of 11,662 t equivalent to 375 Moz, excluding past production for those exploited. A number of probable gold bearing base metals high tonnage deposits (IOCG and porphyry copper) do not include their gold content in public format, hence the number delivered could be estimated conservative. Methodical geochronological, ore types and zonation studies are required to better appreciate this metallogenic setting widening current understanding and future exploration results.

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Gold-bismuth-telluride-sulphide assemblages at the Viceroy Mine, Harare-Bindura-Shamva greenstone belt, Zimbabwe

Mineralogical Magazine ◽

10.1180/minmag.2008.072.4.953 ◽

2008 ◽

Vol 72 (4) ◽

pp. 953-970 ◽

Cited By ~ 26

Author(s):

T. Oberthür ◽

T. W. Weiser

Keyword(s):

Native Gold ◽

Gold Mineralization ◽

Close Association ◽

Shear Zones ◽

Gold Deposits ◽

Orogenic Gold ◽

Main Stage ◽

Melting Temperatures ◽

Native Bismuth ◽

Gold Bearing

AbstractGold mineralization at the Viceroy Mine is hosted in extensional veins in steep shear zones that transect metabasalts of the Archaean Arcturus Formation. The gold mineralization is generally made up of banded or massive quartz carrying abundant coarse arsenopyrite. However, most striking is a distinct suite of Au-Bi-Te-S minerals, namely joseite-A (Bi4TeS2), joseite-B (Bi4Te2S), hedleyite (Bi7Te3), ikunolite (Bi4S3), ‘protojoseite’ (Bi3TeS), an unnamed mineral (Bi6Te2S), bismuthinite (Bi2S3), native Bi, native gold, maldonite (Au2Bi), and jonassonite (AuBi5S4). The majority of the Bi-Te-S phases is characterized by Bi/(Se+Te) ratios of >1. Accordingly, this assemblage formed at reduced conditions at relatively low fS2 and fTe2. Fluid-inclusion thermometry indicates depositional temperatures of the main stage of mineralization of up to 342°C, in the normal range of mesothermal, orogenic gold deposits worldwide. However, melting temperatures of Au-Bi-Te phases down to at least 235°C (assemblage (Au2Bi + Bi + Bi7Te3)) imply that the Au-Bi-Te phases have been present as liquids or melt droplets. Furthermore, the close association of native gold, native bismuth and other Bi-Te-S phases suggests that gold was scavenged from the hydrothermal fluids by Bi-Te-S liquids or melts. It is concluded that a liquid/melt-collecting mechanism was probably active at Viceroy Mine, where the distinct Au-Bi-Te-S assemblage either formed late as part of the main, arsenopyrite-dominated mineralization, or it represents a different mineralization event, related to rejuvenation of the shear system. In either case, some of the gold may have been extracted from pre-existing, gold-bearing arsenopyrite by Bi-Te-S melts, thus leading to an upgrade of the gold ores at Viceroy. The Au-Bi-Te-S assemblage represents an epithermal-style mineralization overprinted on an otherwise mesothermal (orogenic) gold mineralization.

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STALE GOLD-BEARING TAILINGS OF THE BALEIZOLOTO PLANT AND THE PROBLEM OF THEIR DISPOSAL

Transbaikal State University Journal ◽

10.21209/2227-9245-2021-27-4-45-54 ◽

2021 ◽

Vol 27 (4) ◽

pp. 45-54

Author(s):

G. Yurgenson ◽

◽

L. Shumilova ◽

А. Khatkova ◽

◽

...

Keyword(s):

Negative Impact ◽

Chemical Elements ◽

Raw Materials ◽

Precious Metals ◽

Gold Content ◽

Residential Areas ◽

Extraction Technology ◽

Useful Components ◽

Technogenic Raw Materials ◽

Gold Bearing

The relevance of the research is the need to recultivate the waste from the enrichment of gold-bearing ores that lie in the immediate vicinity of the residential areas of Baley city, which have a negative impact on the environmental situation in it, as well as to develop a technological approach to the extraction of gold and silver. The purpose of the study is to study the material composition and develop a technology for extracting precious metals. The object of the study is the stale tailings of the ZIF-1 plant “Baleizoloto”. The subject of the study is mineral composition of stale tailings, content of useful components and their extraction technology, the method and methodology presented by mineralogical and chemical analyses of enrichment tailings. Results. The analysis of the tailings dumps’ state of the gold recovery factories of the Baleizoloto plant was carried out. The contents of gold and other chemical elements, among which arsenic, zinc, copper, antimony, and lead predominate, were determined. The gold content prevails in the stale tailings of the ZIF-1 factory, which processed the ores of the Baley deposit, and is in the range of 1.09-1.37 g / t, on average – 1.17 g/t. This determines the prospects for their primary processing. The gold in the clay-sand fraction of the stale tailings is mainly found in thin accretions with quartz, carbonates, pyrite, arsenopyrite, sulfosols, and tellurides. The field of application is processing of technogenic raw materials. Conclusions. It was determined that the sizes of gold inclusions are in the range of 0.7-0.03 mm, the gold penetration varies from 63 to 91.15, and on average is 82.13; the main impurity in gold is silver with a content of 8.85-37%; the average silver content in the tailings of the ZIF-1 factory is 1.85 g/t; the recommended technological scheme for processing stale tailings of ZIF-1 of the Baleizoloto plant has been developed, including the following operations: photoelectron-activation preparation, pelletizing with active solution, heap leaching, two-stage sorption with bubbling with ozone

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