Mineral Components, Texture, and Forming Conditions of Hydrothermal Chimney on the East Pacific Rise at 9°–10°N
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Bornite
Marcasite
Chimney (locomotive)
Anhydrite
Covellite
Muscovite
Sulfide Minerals
The sulfide mineralization of die Camaqua Mines (Cu) and of the Santa Maria Deposit (Pb-Zn). State of Rio Grande do Sul, southern Brazil, is associated with red bed conglomerates and sandstones, deposited hi an alluvial fan environment at the end of the Brasiliano Event. The non opaque cement and ore mineral analysis allow to identify four main phases hi the mineralization process occurred after the sedimentation: the eodiagenetic and mesogenetic phases are represented by the formation of hematite I-rutile and pyrite I-marcasite, respectively; the late diagenetic to epigenetic phase has occurred at deep burial levels and it was superimposed to the least non opaque cements. It comprises the galena-sphalerite-chalcopyrite paragenesis in the Santa Maria Deposit and the pyrite Il-chalcocite I-bornite I-chalcopyrite paragenetic sucession in the Camaqua Mines; the paleo-oxidation/cementation phase took place after uplift and unroofing. It is well observed in the Camaqua Mines where the previous sulfide phases were altered and replaced by die hematite IT-bomite Il-chalcocite TI-covellite. In the Santa Maria Deposit occur the hematite n-stephanite-chalcocite II-covellite-native silver paragenesis; and the tectonic remobilization phase of the previous ore cements has occurred during bed tilting and leaded to the formation of pvrite-bomite-chalcopyrite-quartz and hematite-bornite-chalcocite-barite-calcite veins in the Camaqua Mines, and only of veinlets with galena-sphalerite in die Santa Maria Deposit. The deposition of die Guaritas Formation occurred when die mineralization process had finished, i.e. after the tilting of die Bom Jardim Group beds.
Chalcocite
Bornite
Covellite
Marcasite
Paragenesis
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A relatively simplified calculation method, presented on two and three dimensional diagrams of log a Cu – log a FeS2 - log f S2 for the Cu-Pe-S system (T = 298 K, p = 1 bar), includes the regions and fields of stability for chalcocite, digenite, bornite, chalcopyrite, covellite, and pyrite (marcasite). The utility of the aforementioned diagrams for the interpretation of sulphide mineralization in black shales is demonstrated with Fore-Sudetic copper resources as an example.
Bornite
Covellite
Chalcocite
Marcasite
Viséan
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Accurate quantification of secondary and primary sulfide minerals is fundamental for resource evaluation, ore processing, and long-term sustainability of mining operations. In addition to visual mapping and automated mineral quantification, chemical analysis can also be harnessed to characterize the mineralogy of ore deposits. By evaluating the conditions in which certain minerals can be selectively dissolved from others, a chemical evaluation could provide geochemical speciation data of low-abundance minerals, such as copper/iron sulfides present in low-grade copper ores. The selective dissolution of copper sulfide minerals is, however, understudied. Here, we evaluate the use of potential selective dissolution conditions to differentiate supergene copper sulfides from hypogene copper sulfides. By characterizing the dissolution kinetics of chalcocite, covellite, bornite, enargite, chalcopyrite, and pyrite concentrates, we found that alkaline cyanidation (and not hydrogen peroxide or acid leaching in the presence of oxidizing agents) selectively dissolves supergene copper sulfides, which can be applied in a sequential extraction scheme to estimate the sulfide mineralogy of tailings samples. Cyanide completely dissolved chalcocite and covellite within 5–15 min, whereas dissolution in acid oxidative media only partially dissolved copper sulfides. Pyrite, chalcopyrite, enargite, and bornite under 0.5% KCN leaching (1 mg/mL) for 10 min showed approximately 1, 10, 30, and 40% of copper recovery, respectively. Cyanide leaching applied in sequential extractions of porphyry copper tailings samples from the Piuquenes impoundment, La Andina, Chile, improved the selective dissolution of secondary sulfides compared to a previously proposed hydrogen peroxide dissolution method, thus allowing their differentiation from primary sulfide minerals. The selective leaching of supergene sulfides by cyanidation provides a cheap and efficient method to estimate the copper sulfide mineralogy in copper ores, facilitating the sustainability and resource evaluation of mining operations.
Covellite
Chalcocite
Bornite
Sulfide Minerals
Supergene (geology)
Copper extraction techniques
Copper sulfide
Cuprite
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The Manus back arc basin is well known for hosting submarine hydrothermal deposits of Vienna Wood, Pacmanus, Onsen site and Solwara 1-12. The Vienna Wood located in the Central Manus basin is a typical Cu-Zn type of mineralization hosted by mid-oceanic ridge basalt and consists predominantly of sphalerite, wurtzite, chalcopyrite and gangue minerals of anhydrite, gypsum and silica. In contrast, the Pacmanus hydrothermal deposit in the eastern part of the Manus basin is hosted by rocks ranging from basalt to dacite and rhyodacite. The mineralization is of the polymetallic Zn-Cu-Pb-Au type consists of ore minerals of sphalerite, chalcopyrite, bornite, wurtzite, pyrite, marcasite, enargite, tennantite, galena, Pb-As-Sulphosalt, gold, covellite, digenite, chalcocite and gangue minerals of barite, amorphous silica, anhydrite and gypsum. The chemical composition of sphalerite, galena, gold and tennantite-tetrahedrite indicate high concentrations of Lead, Arsenic, Silver, Iron, Copper and Antimony compared to their stoichiometric composition. The Onsen site in the Eastern Manus Basin is the first deep sea acid sulfate type of mineralisation and consist of enargite, covellite, chalcopyrite, pyrite, marcasite and gangue minerals of pyrophyllite, alunite, quartz, cristoballite, amorphous silica and native sulfur. The PNG Government has granted exploration and mining licenses to Nautilus Mineral for commercial exploitation of these deposits and Solwara 1 deposit in the Eastern Manus Basin. Nautilus minerals has done extensive exploration and reports indicated and inferred a mineral resource of 1030 kt and 1540 kt respectively for their Solwara 1 project east of Pacmanus site at a 2.6% Cu equivalent cut off grade. Whether this mineral resource is sufficient to deliver PNG first deep sea mining or not will depend on the success of the trial mining method that is currently being developed. Studies done on nearby Pacmanus and Onsen submarine hydrothermal deposits indicate that the deposits contain a much higher proposition of deleterious elements such As, Pb and Sb. Nautilus did not disclose the full mineralogy and assay results of the Solwara 1 and 2 projects to the public domain apart from Cu, Au, Ag and Zn. Nautilus did not suggest how it will address toxic and heavy metals that are associated with the ore concentrate in its Environmental Impact Studies.
Bornite
Marcasite
Covellite
Hypogene
Chalcocite
Tetrahedrite
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Abstract This study aims to determine the characteristics of hydrothermal alteration and the mineralization of sulfide deposits in the Sasak area. The method used is field research which includes observations of lithology, geomorphology, and geological structures and subsurface data collection with geomagnetic and polarization induction (IP), laboratory analysis methods in the form of petrographic, mineragraphy, AAS, and Fire Assay. The alteration characteristics start from strong intense potassic, argillic, and intense silicification to strong intense prophylitic. The mineralization is sulfide consisting of galena (PbS), sphalerite (ZnS), chalcopyrite (CuFeS2), and covellite (CuS) as well as a small amount of chalcocite (CuS2). Limonite, magnetite, and quartz are the dominant accompanying minerals, while gold-silver (Au-Ag) tends to be associated with limonite or quartz. Covellite tends to exist on the surface of chalcopyrite. Galena, sphalerite, chalcopyrite, and covellite are complexly bound to pyrite minerals or between the three minerals in fine sizes, there is even superfine galena as inclusions in pyrite. Based on the characteristics of alteration and mineralization indicates a porphyry-type deposit.
Covellite
Chalcocite
Bornite
Sulfide Minerals
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Bornite
Marcasite
Chimney (locomotive)
Anhydrite
Covellite
Muscovite
Sulfide Minerals
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