scholarly journals Comparison of the chemical-analytical and geological Data on gold-bearing intervals of boreholes in limits of the Zygyrkol zone of Tyrnyauz ore field

2019 ◽  
Author(s):  
С.Г. Парада ◽  
М.Ю. Маркин ◽  
В.В. Столяров ◽  
Х.О. Чотчаев
Keyword(s):  
Native Gold ◽  
Strong Positive Correlation ◽  
Gold Concentration ◽  
Mineralogical Analysis ◽  
Correlative Analysis ◽  
Gold Determination ◽  
Ore Minerals ◽  
Native Bismuth ◽  
Gold Bearing ◽  
Borehole Core

Проведен сопоставительный анализ документации керна буровых скважин и результатов химикоаналитических определений золота в керновых пробах из рудных интервалов золотоносных скарнов Зыгыркольской зоны. Показано, что содержания золота в рудных интервалах не зависят от типа, форм проявления, количества и состава рудных минералов. Отсутствие связи концентраций золота с сульфидами, магнетитом и гематитом подтвердилось и при исследовании пробпротолочек, составленных из хвостов 50 бороздовых проб, отобранных из рудных интервалов, в которых содержания золота по результатам химического анализа составили от 0,6 до 9,9 г/т. Результаты минералогического анализа шлихов показали крайнюю бедность их рудными минералами. В минералогических пробах руд с максимальными содержаниями золота установлены частицы самородного золота, при полном отсутствии в этих пробах сульфидов и других рудных минералов. Множественная корреляция, выполненная по массиву химикоаналитических данных, полученных по результатам кернового опробования золотоносных скарнов Зыгыркольской рудоносной зоны, показала, что золото достаточно сильно положительно коррелируется только с висмутом. Это соответствует минералогическим данным о наличии ассоциации самородного золота с самородным висмутом, установленной по результатам электронномикроскопических исследований. Установлено также отсутствие значимой корреляции золота и серебра, что может свидетельствовать о разных этапах золотой и серебряной минерализаций. Относительно сильная положительная корреляция серебра со свинцом, сурьмой, цинком, мышьяком, марганцем и оловом свидетельствует о связи этого элемента с проявлениями сульфидной минерализации, содержащими галенит, пираргирит и другие сульфоантимониты, сульфоарсениды и сульфостанаты, а также алабандин. Таким образом, установлено, что золотое оруденение в скарнах Зыгыркольской зоны является монометалльным (чисто золотым), образовавшимся раньше так называемых сопутствующих сульфидных и сульфидномагнетитовых минерализаций Тырныаузского рудного поля The correlative analysis of borehole core documentation and results of gold determination in core samples from ore intervals of gold bearing skarns of the Zygyrkol zone has been carried out. It was shown that gold contents in the ore fntervals does not depend on the type, forms of manifestation, number and composition of ore minerals. Absence of connection of gold concentration with sulphides, magnetite and hematite has been also confirmed at investigation of crush samples, composed of tails of 50 trench samples, taken from ore intervals, in which gold contents by results of chemical analysis made from 0.6 to 9,9 g/t. Results of mineralogical analysis of blacksands have shown their extreme poverty in ore minerals. In the mineralogic samples of ores with maximal gold contents there were established particles of native gold, at full absence of sulphides and other ore minerals in these samples. Plural correlation carried out on the array of chemicalanalytic data, obtained by results of core sampling of goldbearing skarns of the Zygyrkol ore bearing zone, has shown that the gold is sufficiently strong correlated only with bismuth. This corresponds to the mineralogical data about existence of association of native gold with native bismuth, established on results of electronmicroscopic research. There is established also absence of significant correlation of gold and silver, what can testify in favor of different stages of golden and silver mineralizations. Relatively strong positive correlation of silver with lead, antimonium, zinc, arsenic, maqnganese and tin, testify about link of this element with manifestations of sulphide mineralization, containing galenite, pyrargyrite and other sulphoantimonites, sulphoarsenides and sulphostannates, and also alabandite. So it has been stated that golden mineralization in skarns of the Zygyrkol zone is monometallic (pure golden), formed earlier than so called attendant sulphide and sulphidemagnetite mineralizations of the Tyrnyauz ore field

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

2008 ◽  
Vol 72 (4) ◽  
pp. 953-970 ◽  
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.

Mineralogická charakteristika hydrotermální mineralizace ze starých těžebních pozůstatků v oblasti Mladoňov - Nový Malín (silezikum)

2020 ◽  
Vol 28 (2) ◽  
pp. 261-275
Author(s):  
Zdeněk Dolníček ◽  
Miroslav Nepejchal ◽  
Vlastimil Flášar ◽  
Jana Ulmanová
Keyword(s):  
Electron Microprobe ◽  
Bohemian Massif ◽  
Native Gold ◽  
Native Copper ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Area North ◽  
Native Bismuth

In the area north of Mladoňov, which is built by phyllites and quartzites of the Vrbno Group and granite-derived phyllonites of the Desná Group (Silesicum, northern part of the Bohemian Massif), there were found two types of hydrothermal ore mineralization in vein material sampled from remnants of old mining/prospection. The Cu(-Bi-Au) mineralization hosted by quartz gangue was found at the locality Husarčina šachta. A main ore mineral is chalcopyrite, which contains inclusions of pyrite, native bismuth, bismuthinite, a phase close to bismite, and native gold with fineness of 717 - 818. Baryte, recorded in part of collected samples, probably represents a significantly younger hypogene mineralization. Supergene minerals include malachite, azurite, a phase close to chrysocolla, bornite, Cu-sulphides, tenorite, native copper, limonite and probably also cuprite. A quartz-pyrite-pyrrhotite mineralization with accessory arsenopyrite and xenotime-(Y) and supergene limonite and baryte was recorded at localities Husarčina šachta and Kopka. Sporadically, Fe-sulphides contain elevated contents of Au (measurable by means of an electron microprobe), probably due to submicroscopic inclusions of native gold. Gold could be leached from wall rocks by ore fluids and/or remobilized from older mineralization to the younger one. The presence of traces of Cr, Co and Ni in some ore minerals implies for wider circulation of parent fluids involving probably also basic or ultrabasic rocks.

New data on the reduced intrusion-related Au mineralization of Central Kolyma gold region: age, formation conditions, composition, orecontrolling factors

2021 ◽  
pp. 68-89
Author(s):  
Nikolay Pachersky ◽  
Sergei Kryazhev ◽  
Eugene Naumov ◽  
Darya Desyatova ◽  
Svetlana Dvurechenskaya ◽  
...  
Keyword(s):  
Late Jurassic ◽  
Native Gold ◽  
Rare Metal ◽  
Ore Deposits ◽  
Ore Deposit ◽  
Fracture Systems ◽  
Formation Conditions ◽  
Native Bismuth ◽  
Gold Bearing

New data are presented on the formation conditions and ages of the reduced intrusion-related Au mineralization of the Vetrenskaya area in the Central Kolyma region. The mineralization is predominantly confined to intersections of Late Jurassic minor intrusive bodies and NE-trending fracture systems and is represented by zones of thin quartz veinlets with sericite-quartz halos. The major ore mineral is gold-bearing arsenopyrite (up to 10%), while minor minerals are represented by lellingite, pyrite, chalcopyrite, and pyrrhotite. Microscopic native gold of a low fineness is paragenetically associated with bismuth minerals (bismuthine, native bismuth, andtellurides of Bi and Au), forming microinclusions (1–10 μ) in the arsenopyrite. Isochronous Re-Os age of the goldbearing arsenopyrite is 137–117 Ma, which suggests the mineralization was formed significantly later than the hosting granitoids (147–153 Ma). The reduced intrusionrelated Au ore deposit was formed at shallower depths in comparison with orogenic Au deposits, and at lower temperatures in comparison with rare metal (W, Mo) ore deposits.

scholarly journals SEM studies of ore minerals in skarns from Garby Izerskie, Karkonosze-Izera block, south-western Poland

2013 ◽  
Vol 2 (1) ◽  
pp. 61-66
Author(s):  
Maciej Rybicki ◽  
Łukasz Karwowski ◽  
Kamila Banasik
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Native Gold ◽  
Reflected Light ◽  
Sem Study ◽  
Microscopical Method ◽  
Ore Minerals ◽  
Native Silver ◽  
Native Bismuth ◽  
Scanning Electron

Abstract In “Stanisław” quarry, that is located on Garby Izerskie, ore minerals-bearing calcsilicate skarns were found in 2009. The samples were studied using microscopical method of reflected light and scanning electron microscopy (SEM). Based on SEM study, the predominant ore minerals in investigated samples are chalcopyrite, pyrrhotite, bismuth telluride and native bismuth. Moreover, acanthite, native gold and native silver were also identified. Our studies are the first report of above mentioned minerals from the Garby Izerskie area.

Gravity-flotation gold-bearing ore concentration

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.

Predictive geochemistry of ore gold in Eastern Transbaikalia

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

scholarly journals Minerály kontaminovaných granitových pegmatitů z lomu Pohled u Havlíčkova Brodu (moldanubikum), část II: prvky a sulfidy

2021 ◽  
Vol 29 (1) ◽  
pp. 90-107
Author(s):  
Zdeněk Dolníček ◽  
Jana Ulmanová ◽  
Karel Malý ◽  
Jaroslav Havlíček ◽  
Jiří Sejkora
Keyword(s):  
Raman Spectrum ◽  
Metamorphic Rocks ◽  
Mineral Association ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Mineralogical Study ◽  
Native Bismuth ◽  
Polymetallic Ore ◽  
Hydrothermal Veins ◽  
Cobalt And Nickel

In the Pohled quarry near Havlíčkův Brod town (central part of Czech Republic), texturally and mineralogically simple contaminated anatectic pegmatites form dikes or irregular bodies cementing breccia of host metamorphic rocks (paragneisses, amphibolites) belonging to the Monotonous (Ostrong) Group of the Moldanubicum of the Bohemian Massif. They exhibit signs of intense hydrothermal overprint and also the presence of abundant disseminations, nests and veinlets of ore minerals. A detailed mineralogical study revealed the presence of an extraordinary rich ore assemblage (20 species in total, including one unnamed phase). The oldest minerals are sphalerite (rich in Fe), löllingite, Fe-Co-Ni sulphoarsenides (cobaltite, glaucodot, arsenopyrite, gersdorffite), pyrrhotite, galena and chalcopyrite, in later portion accompanied by inclusions of Bi-minerals (native bismuth, bismuthinite, joséite-A, joséite-B, ikunolite and a Pb-Bi sulphosalt). The composition of the Pb-Bi sulphosalt is equal to Ag,Fe-substituted eclarite; its identity was confirmed also by Raman spectrum. Pyrite is very abundant phase, present probably in several generations. The Fe-Co-Ni thiospinels disseminated in younger chlorite, and represented by siegenite, violarite, grimmite and an unnamed NiFe2S4 phase, are the youngest ore minerals. The mineral association as well as chemical composition of most ore minerals are well comparable to those of local polymetallic ore veins and Alpine-type veins, which give evidence for identical origin of all these ore mineralizations. The formation of pegmatite-hosted ore assemblage was long-lasting multiphase process, which took place at temperatures between ca. 350 and <120 °C during changing fugacities of sulphur, tellurium and oxygen. A distinct enrichment in cobalt and nickel of ore mineralization hosted by pegmatites (in comparison with hydrothermal veins) is explained in terms of pronounced interactions of fluids with amphibolites and serpentinites.

Geology of the Liese Zone, Pogo Property, East-Central Alaska

SEG Discovery ◽  
1999 ◽  
pp. 1-21
Author(s):  
MOIRA SMITH ◽  
JOHN F.H. THOMPSON ◽  
JASON BRESSLER ◽  
PAUL LAYER ◽  
JAMES K. MORTENSEN ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Gold Mineralization ◽  
Geochemical Data ◽  
East Central ◽  
Gold Silver ◽  
Ore Minerals ◽  
Middle Paleozoic ◽  
Deposit Type ◽  
Alteration Minerals ◽  
Native Bismuth

ABSTRACT The Liese zone is a recently discovered high-grade gold deposit on the Pogo claims, approximately 90 miles (145 km) southeast of Fairbanks. A conservative geologic resource for the Liese zone is 9.98 million tons at an average grade of 0.52 oz/t, for a total of 5.2 million contained ounces. The region is underlain by highly deformed, amphibolite-grade paragneiss and minor orthogneiss of the Late Proterozoic(?) to middle Paleozoic Yukon-Tanana terrane, which has been intruded by Cretaceous felsic granitoid bodies thought to be related to gold mineralization in the Fairbanks area and elsewhere along the Tintina gold belt. The Liese zone is hosted primarily in gneiss, and lies approximately 1.5 km south of the southern margin of the Late Cretaceous Goodpaster batholith. Mineralization occurs in three or more tabular, gently dipping quartz bodies, designated L1 (uppermost), L2, and L3 (lowermost). The thickness of the quartz bodies ranges from 1 to 20 m, averaging approximately 7 m. The quartz contains approximately 3 percent ore minerals, including pyrite, pyrrhotite, loellingite, arsenopyrite, chalcopyrite, bismuthinite, various Ag-Pb-Bi ± S minerals, maldonite, native bismuth, and native gold. Early biotite and later quartz-sericite-stockwork and sericite-dolomite alteration are spatially associated with the Liese zone, which shows characteristics of both vein and replacement styles of mineralization. Geochemical data indicate a strong correlation between gold and bismuth, and weaker correlations between gold, silver, and arsenic. Based on U-Pb dating of intrusive rocks, the Liese zone was formed between 107 and 94.5 m.y. ago, although 40Ar/39Ar cooling ages on alteration minerals return younger ages of 91 Ma, suggesting a protracted or multiphase thermal history. The Liese zone may represent a deep-seated manifestation of the "intrusion-related" gold deposit type.

scholarly journals STRUCTURAL AND MORPHOLOGICAL FEATURES OF VERBA MOLYBDENUM ORE MINERALIZATION

2018 ◽  
pp. 15-19
Author(s):  
M. M. Kostenko ◽  
P. A. Kondratenko
Keyword(s):  
Internal Structure ◽  
Complex Structure ◽  
Morphological Features ◽  
Ukrainian Shield ◽  
Granite Massif ◽  
South Eastern ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Mineralized Zone ◽  
Native Bismuth

The article shows the Verba ore mineralization of molybdenum (Volyn Block of the Ukrainian Shield) is associated with small granite intrusions. They are located in the south-eastern exocontact zone of the Ustynivka granite massif of the Paleoproterozoic Chisinau complex. The Verba minera­lization is a linear-coarse mineralized zone of the complex structure. This is confirmed by the development in its rocks of frequent, non-orientated veins of quartz, fluorite-quartz and carbonate-quartz compositions and numerous cracks. They have molybdenite and concomitant mineralization, as well as the wide spreading of molybdenite inclusions directly in the granites. A number of differently oriented faults and of small fracturing local zones, cataclasite, millonitized and breccias represents the internal structure of the mineralized zone. The characteristic of molybdenite the leading ore minerals is shown. It is morphologically represented by a closely connected scattered inclusions, rarely veined inclusions, and associated ore minerals: cassiterite, bismuth, native bismuth, emlectocytes, galena, sphalerite, chalcopyrite, pyrite, ilmenite, magnetite and titanomagnetite.

scholarly journals The first find of silver nuggets in gold placers of Subpolar Urals

2019 ◽  
Vol 486 (6) ◽  
pp. 714-717
Author(s):  
T. P. Mayorova ◽  
S. K. Kuznetsov ◽  
V. N. Filippov
Keyword(s):  
Primary Sources ◽  
Small Particles ◽  
Research Results ◽  
Subpolar Urals ◽  
Mineral Phases ◽  
Gold Silver ◽  
Native Bismuth ◽  
First Time ◽  
Gold Bearing

For the first time, silver nuggets were found in the gold-bearing placers of the Subpolar Urals. Galena, cassiterite, wolframite, cosalite, tetradymite, ferberite, cobaltine, joseite-B, native bismuth associate with silver and gold. Silver is mainly represented by poorly rounded and non-round gray lumpy, slightly flattened, elongated particles of 2-2.5 cm size. As part of silver, Au and Hg sometimes contain impurities. Inclusions are represented by small particles of gold, bismuth and tellurium mineral phases. Research results indicate a fairly widespread development of Au-Ag-Bi-Te mineralization, the primary manifestations of which are not yet known in the region. Relatively weak roundness of silver nuggets, presence of major and poorly rounded gold indicates the proximity of the primary sources to gold-bearing placers.

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