scholarly journals Incorporation of Geometallurgical Input into Gold Mining System Simulation to Control Cyanide Consumption

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1023
Author(s):  
Javier Órdenes ◽  
Ryan Wilson ◽  
Felipe Peña-Graf ◽  
Alessandro Navarra
Keyword(s):  
Volcanic Rocks ◽  
Precious Metals ◽  
Mining System ◽  
Process Simulations ◽  
Ore Minerals ◽  
Base Metal Sulphides ◽  
Cyanide Consumption ◽  
Process Elements ◽  
Operational Modes ◽  
Consumption Control

The Alhué deposit (Melipilla, Chile) is an example of a hydrothermal Au-Ag-Zn(-Pb) vein system hosted within the volcanic rocks of the Las Chilcas Formation. The dominant ore minerals observed are free electrum and native gold associated with silver sulfosalts, and with magnetite and base metal sulphides, including pyrite +/− sphalerite-galena-chalcopyrite. The alteration assemblage in the veins mainly consists of quartz epidote-chlorite-actinolite with lesser smectite, amphibole, and calcite-kaolinite-garnet. Mineralized veins also contain variable amounts of base metals, some of which (e.g., copper and iron) are considered harmful to the extraction of precious metals. Iron and especially copper minerals are known cyanide consumers; ore type classification schemes that do not consider the detrimental effects of such mineralogy or process elements can ultimately result in metal losses from ore feed restrictions, as well as spikes in cyanide consumption and higher operating costs. Mineralogical and geological variation can nonetheless be managed by applying alternating modes of operation as demonstrated in this paper; the decision to switch between modes is governed by current and forecasted stockpile levels feeding into the process. Simulations based on experiences at the Alhué deposit are provided that demonstrate the importance of standardized operational modes and their potential impact on cyanide consumption control.

The Witwatersrand pyrites and metamorphism

1983 ◽  
Vol 47 (345) ◽  
pp. 473-479 ◽  
Author(s):  
D. K. Hallbauer ◽  
K. von Gehlen
Keyword(s):  
Trace Element ◽  
Fluid Inclusions ◽  
Depositional Environment ◽  
Volcanic Rocks ◽  
Source Rocks ◽  
Fine Grained ◽  
Mineral Inclusions ◽  
Ore Minerals ◽  
Hand Specimen

AbstractEvidence obtained from morphological and extensive trace element studies, and from the examination of mineral and fluid inclusions in Witwatersrand pyrites, shows three major types of pyrite: (i) detrital pyrite (rounded pyrite crystals transported into the depositional environment); (ii) synsedimentary pyrite (round and rounded aggregates of fine-grained pyrite formed within the depositional environmen); and (iii) authigenic pyrite (newly crystallized and/or recrystallized pyrite formed after deposition). The detrital grains contain mineral inclusions such as biotite, feldspar, apatite, zircon, sphene, and various ore minerals, and fluid inclusions with daughter minerals. Most of the inclusions are incompatible with an origin by sulphidization. Recrystallized authigenic pyrite occurs in large quantities but only in horizons or localities which have been subjected to higher temperatures during the intrusion or extrusion of younger volcanic rocks. Important additional findings are the often substantial amounts of pyrite and small amounts of particles of gold found in Archaean granites (Hallbauer, 1982) as possible source rocks for the Witwatersrand detritus. Large differences in Ag and Hg content between homogeneous single gold grains within a hand specimen indicate a lack of metamorphic homogenization. The influence of metamorphism on the Witwatersrand pyrites can therefore be described as only slight and generally negligible.

Mineralogy and textural relationships of ores from the Whalesback Mine, northeastern Newfoundland

1968 ◽  
Vol 5 (6) ◽  
pp. 1387-1395 ◽  
Author(s):  
K. Kanehira ◽  
D. Bachinski
Keyword(s):  
Shear Zone ◽  
Volcanic Rocks ◽  
Sulfide Deposit ◽  
Ore Formation ◽  
Pillow Lavas ◽  
Bay Area ◽  
Internal Reaction ◽  
Sulfide Ore ◽  
Ore Minerals ◽  
Pressure Shadow

The Whalesback Mine is one of many copper deposits associated with Ordovician volcanic rocks in the Notre Dame Bay area, Newfoundland. The deposit consists of veins, pods, and disseminated sulfides localized within a highly chloritized shear zone cutting basaltic pillow lavas. Porphyritic dikes cut the shear zone, sulfide deposit, and the surrounding pillow lavas; all of the rocks, including the sulfide-rich rocks, have been regionally metamorphosed. Ore minerals, in decreasing order of abundance, include pyrite, chalcopyrite, pyrrhotite, sphalerite, mackinawite, pentlandite, magnetite, cubanite, galena, and ilmenite. Marcasite, covellite, and goethite are supergene minerals. Chlorite and quartz are the predominant gangue minerals. Muscovite, carbonates, sphene, albite, and epidote are minor constituents. Banding and streaking of sulfides in massive ores, crushed pyrite, and the local occurrence of pressure-shadow phenomena in the ore are indicative of shearing stress post-dating original sulfide ore formation. Present sulfide assemblages are compatible with relatively low temperatures and are the result of re-equilibration and internal reaction among the sulfides with decreasing temperature.

Characteristics of ore minerals associated with gold at the Prestea mine, Ghana

1997 ◽  
Vol 61 (409) ◽  
pp. 879-894 ◽  
Author(s):  
Napoleon Q. Hammond ◽  
Hirokazu Tabata
Keyword(s):  
Gold Mineralization ◽  
Stoichiometric Composition ◽  
Oscillatory Zoning ◽  
Main Stage ◽  
Type I ◽  
Two Phase ◽  
Ore Minerals ◽  
Ideal Stoichiometry ◽  
Base Metal Sulphides ◽  
The Ideal

AbstractGold in Early Proterozoic Birimian greenstone at Prestea in Ghana is associated with base metal sulphides and sulphosalts including arsenopyrite, pyrite, sphalerite, chalcopyrite, pyrrhotite, galena, tetrahedrite, bournonite, boulangerite and jamesonite. The occurrence of the gold is intimately associated with arsenopyrite and the sulphosalts, and to a lesser extent with the other sulphides. The tetrahedrites at Prestea constitute the major component of sulphosalts associated with gold and occurring in two distinct types. Type I show ideal stoichiometric composition. Type II tetrahedrites deviated from the ideal stoichiometry and are represented approximately by the average formula (Cu,Ag)9.61(Fe,Zn)2.39(Sb,As)4S13. The tetrahedrites co-precipitated with gold exhibit ideal characteristics indicating an equilibruim state of the mineralizing fluid during precipitation. Three types of pyrites were distinguished by electron-microprobe analyses based on their As, Co and Ni composition. The As content in type I vary from 0.15 to 0.37 wt%, and contain up to 2 wt.% Co.Type II pyrites are As-rich and form the most dominant with As content ranging from 0.2 to 2.69 wt.%. Ni content varies from below-detection to 1000 ppm. Type III pyrites are poor in the trace elements and consistent with the stoichiometric composition. The mineralization occurred in three paragenetic stages from at least a two-phase hydrothermal fluid, with stage II forming a prolonged and main stage of the ore and gold mineralization. Redox changes in ore fluid which were triggered by episodic pressure releases during fissuring and fracturing caused fluctuation of the activity of the As/Ni ratio and subsequent oscillatory zoning of Ni in As-rich ores.

scholarly journals Textural Characteristics of Noncrystalline Silica in Sinters and Quartz Veins: Implications for the Formation of Bonanza Veins in Low-Sulfidation Epithermal Deposits

Minerals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 331 ◽  
Author(s):  
Tadsuda Taksavasu ◽  
Thomas Monecke ◽  
T. Reynolds
Keyword(s):  
Power Plant ◽  
Precious Metal ◽  
Precious Metals ◽  
Fused Silica ◽  
Silica Microspheres ◽  
Textural Characteristics ◽  
Epithermal Deposits ◽  
Ore Minerals ◽  
Low Sulfidation ◽  
Ore Deposition

Silica sinters forming at the Wairakei geothermal power plant in New Zealand are composed of noncrystalline opal-A that deposited rapidly from cooling geothermal liquids flashed to atmosphere. The sinter is laminated with alternating layers of variably compacted silicified filamentous microbes encased by chains of fused silica microspheres. Microscopic inspection of bonanza quartz vein samples from the Buckskin National low-sulfidation epithermal precious metal deposit in Nevada showed that colloform bands in these veins exhibit relic microsphere textures similar to those observed in the silica sinters from the Wairakei power plant. The textural similarity suggests that the colloform bands were originally composed of noncrystalline opal-A that subsequently recrystallized to quartz. The colloform bands contain dendrites of electrum and naumannite that must have grown in a yielding matrix of silica microspheres deposited at the same time as the ore minerals, implying that the noncrystalline silica exhibited a gel-like behavior. Quartz bands having other textural characteristics in the crustiform veins lack ore minerals. This suggests that ore deposition and the formation of the colloform bands originally composed of compacted microspheres of noncrystalline silica are genetically linked and that ore deposition within the bonanza veins was only episodic. Supersaturation of silica and precious metals leading to the formation of the colloform bands may have occurred in response to transient flashing of the hydrothermal liquids. Flashing of geothermal liquids may thus represent a key mechanism in the formation of bonanza precious metal grades in low-sulfidation epithermal deposits.

scholarly journals Geochronology of the so-called South Bulgarian granitoids – a review (1836–2000)

2017 ◽  
Vol 46 (2) ◽  
pp. 40
Author(s):  
Vasil Arnaudov
Keyword(s):  
Quantitative Methods ◽  
Lead Isotope ◽  
Lead Isotopes ◽  
Volcanic Rocks ◽  
The South ◽  
Granitoid Magmatism ◽  
Basic Model ◽  
Ore Minerals ◽  
Geochemical Studies ◽  
Metamorphic Complexes

This review treats the concepts concerning the age of granitoid magmatism in southern Bulgaria and considers the age assessments of the large granite intrusions in the metamorphic complexes known as “South Bulgarian granites”. In terms of the available contributions, this analysis encloses a long period, from 1836, the time of Ami Boué, the first geologist who visited Bulgarian land, to 2000. The review discusses both ideas and geochronological data on a large time-span, from the Archean to the “Tertiary”. The emphasis is on the progress of Bulgarian researchers’ views that had been made prior to the first pioneering attempts at radiological determinations (i.e., using He and Pb quantitative methods), and especially after the advent of modern equipment for radioisotope dating, based on various isotope systems (e.g., K-Ar, U-Th-Pb, Rb-Sr) and mathematical models of lead isotopes (Pb-Pb) following the basic model of “plumbotectonics” and the fission track method. The bulk of radioisotope data (more than 300 dates on feldspar and 500 dates on galena and other ore minerals) have been made by using the Pb-Pb method, which was introduced by Blagoy Amov and improved by the same worker via his “dynamic model of a continuous lead-isotope evolution” in the Earth’s crust. From 1969, when pegmatites that are genetically linked to granite intrusions of southern Bulgaria were dated as “Tertiary”, until 2000, all of the above-mentioned methods were tested. These methods confirmed the “Tertiary” ages of the granitoids of the Rhodope Massif and their difference in age from the Hercynian granitoids of the Srednogorie Zone. Owing to this, two groups of granitoids of dissimilar ages, previously referred to as “South Bulgarian granites”, were determined. This distinction was corroborated by varieties of mineralogical, petrological and geochemical studies, which were carried out by collaborators from the Department of Geochemistry of the Geological Institute. The “magical boundary”, defined by Acad. Strashimir Dimitrov and followed by the majority of Bulgarian geologists, that “the South Bulgarian granites are pre-Mesozoic in age, since fragments of them are present in the Permian–Triassic conglomerates of the Lozen Mountain” has been overcome, mainly due to the results of geochemical studies. Also, the absence of Archean and Proterozoic metamorphism in the Rhodope Massif has been revealed by U-Th-Pb and Pb/Pb radiogeochronological investigations. The analysis of available mineralogical, geochemical and radiogeochronological data, supported by the ages of the migmatites from Ardino area (63–32 Ma), allowed to assume that both migmatized gneisses and the South Bulgarian granites of the Rila and Rhodope Mountains, as well as the volcanic rocks and associated intrusions and ore mineralizations, were a product of a single and prolonged stage of the Alpine activation of the Rhodope crystalline complex that started during the Cretaceous.

On genesis of massive sulfide polymetallic ore deposits of Rudny Altai

2021 ◽  
pp. 3-16
Author(s):  
B. DIYACHKOV ◽  
M. MIZERNAYA ◽  
A. PYATKOVA ◽  
A. BISATOVA ◽  
A. MIROSHNIKOVA ◽  
...  
Keyword(s):  
Precious Metals ◽  
Massive Sulfide ◽  
Ore Deposits ◽  
Vertical Range ◽  
Long Duration ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
High Concentrations ◽  
Individual Grains ◽  
Polymetallic Ore

Many geologists assign most of large- and medium-sized massive sulfide polymetallic ore deposits of Eastern Kazakhstan to the VMS type. These ore deposits formed in the Devonian, under conditions of rifting and active basalt-andesite-rhyolite volcanism. Ore bodies of these deposits are noted to be clearly confined to formations of several geochronologic levels (D1e to D3fm). Hydrothermal-sedimentary syngenetic and hydrothermal-metasomatic ores are distinguished. High concentrations of base metals in the ores (above 10 % sum metals) and their rather simple mineral composition (chalcopyrite, pyrite, galena, and sphalerite) are a characteristic feature of all the massive sulfide polymetallic ore deposits of Rudny Altai. The ores are noted to be multicomponental, with elevated contents of the admixtures of precious metals and rare elements (Cd, Se, Bi, Te, Ta, W, etc.). Mineralogical investigations of the ores have demonstrated an intricate relationships of the major ore minerals (chalcopyrite, pyrite, sphalerite, galena) that exhibit several generations and different geochemical specialization. Minerals of Au, Ag, Te, Bi, and other elements are encountered as individual grains or microscopic inclusions and stringers in minerals of Cu, Pb, and Zn. A significant vertical range of the ore mineralization (more than 100 m), the complexity and long duration of the ore-forming processes, the clearly defined confinement of the ore mineralization to certain geochronologic levels, – all these allow us to suppose a possibility of discovery of new ore lodes or individual ore deposits within the already known ore fields of the Kazakhstan segment of Rudny Altai

Material Composition of Technogenic Ores in Tails of Zhezkazgan Enrichment Factory (Central Kazakhstan)

2016 ◽  
Vol 858 ◽  
pp. 366-370
Author(s):  
Adilkhan Baibatsha ◽  
Kulyash Dyussembayeva ◽  
Alma Bekbotayeva
Keyword(s):  
Grain Size ◽  
Raw Materials ◽  
Precious Metals ◽  
Microscopic Description ◽  
Reliable Source ◽  
Ore Minerals ◽  
Lead Zinc ◽  
And Storage ◽  
Extraction Of Metals ◽  
Copper Lead

Total reserves in tails in enrichment factories account for about 1.0 billion tons, and they contain copper, lead, zinc and precious metals. Therefore such tailings can be considered a major technological company and a reliable source of raw materials to build of processing company. We have studied the conditions of distribution and storage of tailings from enrichment plants. Microscopic description of the tailings material gave the following data. Chalcopyrite prevalent among the copper minerals covellite is most common in the second place, rare chalcocite, bornite, sphalerite, pyrite, arsenopyrite. The grain size of the sulfides is generally 0.01-0.03 mm. The sulfides are mainly quartz or fused to it. Rarely observed aggregates are covellite-bornite, chalcopyrite-covellite and chalcopyrite-bornite. However, not all sulphides ore sufficiently disclosed, most of them are located within grains the surrounding rocks. If disclosed ore minerals associated with grains of rocks less than 100 microns, they can be readily available for leaching. To increase the fullness of extraction of metals from sulfide located inside rock grains larger than 150-200 microns, additional measures for their opening.

Textural Characteristics of Barren and Mineralized Colloform Quartz Bands at the Low-Sulfidation Epithermal Deposits of the Omu Camp in Hokkaido, Japan: Implications for Processes Resulting in Bonanza-Grade Precious Metal Enrichment

2020 ◽  
Author(s):  
Lauren R. Zeeck ◽  
Thomas Monecke ◽  
T. James Reynolds ◽  
Erik R. Tharalson ◽  
Katharina Pfaff ◽  
...  
Keyword(s):  
Precious Metal ◽  
Precious Metals ◽  
High Grade ◽  
Metal Enrichment ◽  
Near Surface ◽  
Epithermal Deposits ◽  
Fine Grained ◽  
Precursor Phase ◽  
Ore Minerals ◽  
Low Sulfidation

Abstract The Miocene low-sulfidation epithermal deposits of the Omu camp in northeastern Hokkaido, Japan, are small past-producers of precious metals and represent significant exploration targets for high-grade Au and Ag ores. The quartz textures of ore samples and the distribution of ore minerals within quartz veins were studied to identify the processes that resulted in the bonanza-grade precious metal enrichment in these deposits. In the high-grade vein samples, which are crustiform or brecciated in hand specimen, ore minerals exclusively occur within colloform quartz bands. High-magnification microscopy reveals that ore-bearing colloform bands consist of fine-grained quartz exhibiting relic microsphere textures and quartz having a mosaic texture that formed through recrystallization of the microspheres. The presence of relic microspheres is evidence that the microcrystalline quartz hosting the ore minerals formed through recrystallization of a noncrystalline silica precursor phase. The ore-hosting colloform bands composed of agglomerated microspheres alternate with barren colloform quartz bands that are composed of fibrous chalcedonic quartz and mosaic quartz formed through recrystallization of the chalcedony. The findings of this study are consistent with previous models linking bonanza-grade precious metal enrichment and the formation of bands of noncrystalline silica in low-sulfidation epithermal veins to episodic vigorous boiling or flashing of the hydrothermal system in the near-surface environment.

Iron sulphides at the epithermal gold-copper deposit of Palai-Islica (Almería, SE Spain)

2003 ◽  
Vol 67 (5) ◽  
pp. 1059-1080 ◽  
Author(s):  
F. J. Carrillo Rosúa ◽  
S. Morales Ruano ◽  
P. Fenoll Hach-Alí
Keyword(s):  
Trace Elements ◽  
Volcanic Rocks ◽  
Copper Deposit ◽  
Metastable Solid Solution ◽  
Se Spain ◽  
Quartz Veins ◽  
Type Iv ◽  
Different Types ◽  
Iron Sulphides ◽  
Ore Minerals

AbstractAu-Cu mineralization at Palai-Islica occurs as disseminations in massive silicified volcanic rocks and, more abundantly, in sulphide-bearing quartz veins. The major ore minerals in the deposit are pyrite ± chalcopyrite, sphalerite and galena and there is a great variety of accessory minerals, including Au-Ag alloys and native gold. Pyrite, the most abundant sulphide, is closely associated with gold. Seven different types of pyrite have been distinguished with a variable concentration of different trace elements. Among these, the only one free of trace elements (type IV) is related to Au-Ag alloys. Pyrite associated with these Au-Ag alloys has cubic and pentagonal dodecahedral habits, whereas pyrite with pentagonal dodecahedral habit only is from barren zones. In addition, there is no significant invisible gold in the pyrite, but there is a relatively large amount of Ag in collomorphic pyrite (up to 0.20 wt.%) or type III pyrite (up to 1.47 wt.%). Arsenic is the most abundant trace element in pyrite (up to 6.11 wt.%), present as a metastable solid solution or as a non-stoichiometric element. A variety of marcasite related to the gold levels also has a considerable amount of trace elements (As up to 1.15 wt.%, Sb up to 0.40 wt.%).

Sign in / Sign up

Export Citation Format

Share Document