Segui questo link per vedere altri tipi di pubblicazioni sul tema: Copper ores.
Tesi sul tema "Copper ores"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Vedi i top-50 saggi (tesi di laurea o di dottorato) per l'attività di ricerca sul tema "Copper ores".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Vedi le tesi di molte aree scientifiche e compila una bibliografia corretta.
1
Seifelnassr, A. A. S. "Bacterial aided percolation leaching of copper sulphide ores". Thesis, Bucks New University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234445.
Testo completo
2
Groenewald, Nico Albert. "Measuring the dielectric properties of crushed copper ore". Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5230.
Testo completoAbstract (sommario):
Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: Previous work has shown that microwave heating of mineral ores induces micro cracks within the ore structure, which can be attributed to the difference in the adsorption of microwaves amongst the different mineral phases. This reduces the energy required during subsequent grinding and enhances the liberation of valuable minerals. In order to design microwave applicators for this purpose, knowledge of the effective dielectric properties of the crushed ore is required. Of particular interest is the effective complex permittivity of the bulk crushed ore. The measurement of the effective permittivity of a large volume of crushed ore is most readily accomplished using the waveguide measurement technique. In this method a representative sample of the material is placed in a defined and fixed volume in a standard size rectangular section metallic waveguide. The magnitude and phase angle of the transmitted and reflected low power microwaves through and from the sample are measured. The complex permittivity can be extracted from these so-called scattering, or Sij parameters. In this study the effective complex permittivities for two porphyry copper ores and a copper carbonatite ore were determined as a function of particle size distribution (-26.5+2mm) using two sizes of waveguide (WR284 and WR340). The sample holders incorporate dielectric windows for the location of the material under test. The extraction of dielectric properties from Sij parameter measurements is problematic using standard algorithms in such cases. Accordingly a new Database Extraction (DBE) Algorithm has been developed. In this method, a database of scattering parameters is established through electromagnetic modelling of the measurement system. A search algorithm is used to determine the effective complex permittivity of the modelled load whose scattering parameters provide the best fit to the experimental data. The goodness of the experimental fit of the simulated to the measured Sij parameters is determined by a root mean squared deviation minimisation metric. Results show that the method can be used successfully to determine an effective complex permittivity for a bulk volume of the crushed material. It is concluded that the dielectric property extraction over the full operational frequency interval (2.3-3 GHz) is preferred as it has a larger degree of extraction confidence and hence reliability. Results show that with increasing particle size, the experimental fit between the simulated and measured Sij parameters becomes increasingly poor, as wall effect become more prominent. The effect is most prominent for the smaller WR284 waveguide size. It is shown that for a waveguide size of similar size to the particle size, the Sij parameter fitting is poorer compared to when a larger waveguide size is used. The extracted complex permittivity reproducibility between repeated dielectric property measurements is improved for the WR340 waveguide size, as the extractions in the WR284 waveguide is dominated by the combined particle size and wall-effects of the sample holder. Ore mineralogy is identified as a key parameter that influences the dielectric properties of the crushed ore. For ores with a dominant microwave absorbent mineral phase, the dielectric constant and loss factor is found to be larger, compared with ores with a more dominant microwave transparent gangue mineral phase.
AFRIKAANSE OPSOMMING: Navorsing toon dat die verhitting van mineraal erts, met mikrogolwe, mikroskaal frakture in die mineraalstruktuur teweeg bring weens die verskil in die adsorpsie van mikrogolwe in die verskillende mineraalfases. Gevolglik verminder die energievereiste vir die vergruising van die erts en verbeter die vrystelling van waardevolle minerale wat vasgevang is in die mineraalmatriks. Vir die ontwerp van mikrogolfapplikators vir dié doel, word die effektiewe diëlektriese eienskappe van die vergruisde erts benodig. Van spesifieke belang is die effektiewe komplekse permittiwiteit van die erts. Die effektiewe permittiwiteit van `n vergruisde materiaal monster word met behulp van die golfgeleier tegniek gemeet. Vir dié tegniek word `n verteenwoordigende monster van die materiaal in `n rigiede volume in `n standaard grootte reghoekige golfgeleier geplaas. Die grootte en fasehoek komponente van die deurgelate en weerkaatste mikrogolwe deur en van die oppervlak van die materiaal word gemeet. Die komplekse permittiwiteit van die vergruisde materiaal kan geëkstrakteer word vanaf hierdie sogenaamde verspreide, of Sij parameters. In hierdie studie word die effektiewe permitiwiteit van twee porforie koper ertse en `n koper karbonatiet erts bepaal as funksie van partikel grootte (-26.5+2 mm) deur gebruik te maak van twee standaard grootte golfgeleiers. Die monster houers inkorporeer diëlektriese vensters om die vergruisde materiaal monster in posisie te hou. In so `n geval is die ekstraksie van die diëlektriese eienskappe vanuit die Sij parameter metings problematies. Gevolglik is ‘n nuwe Databasis Ekstraksie Algoritme ontwikkel wat `n databasis van verspreide parameters opstel deur die elektromagnetiese simulasie van die metingsisteem. `n Soek-algoritme word gebruik om die effektiewe komplekse permitiwiteit van die gesimuleerde monster te bepaal wat die beste ooreenstem met dié van die gemete eksperimentele Sij parameter data. Die mate van ooreenstemming tussen die parameters, word bepaal aan die hand van die minimaliserings prosedure. Resultate toon dat dié metode geskik is vir die bepaling van die effektiewe komplekse permitiwiteit van die vergruisde monster. Dit word vasgestel dat die betroubaarheid van die geëkstraeerde Sij parameters, en gevolglik die diëlektriese eienskappe van die erts, toeneem indien die algoritme oor `n groter frekwensie band uitgevoer word. Resultate toon verder dat met toenemende partikel grootte, die mate waartoe die absolute grootte en fasehoek komponente van die gesimuleerde en gemete Sij parameters ooreenstem, versleg. Dit word toegeskryf aan wand-effekte. Hierdie verskynsel is veral opmerklik vir die kleiner grootte golfgeleier. Dit word getoon dat vir metings waar die golfgeleier dieselfde orde grootte geometriese afmetings het as die vergruisde erts self, die passing tussen die gesimuleerde en gemete Sij parameters swakker is, wanneer dit vergelyk word met metings waar dit nie die geval is nie. Die reproduseerbaarheid van die geëkstraeerde diëlektriese eienskap waardes verbeter vir lesings wat uitgevoer word in `n groter grootte golfgeleier. Laasgenoemde word toegeskryf aan die meer dominante wand-effekte wat kenmerklik is vir `n kleiner golfgeleier. Erts mineralogie word geïdentifiseer as `n sleutel parameter wat die diëlektriese eienskappe van die vergruisde materiaal beïnvloed. Beide die diëlektriese konstante en verliesfaktor is groter vir ertse met `n oorheersende mikrogolf absorberende mineraalfase.
3
Gendall, Ian Richard. "The porphyry copper system and the precious metal-gold potential". Thesis, Rhodes University, 1994. http://hdl.handle.net/10962/d1005604.
Testo completoAbstract (sommario):
It has been established that porphyry copper/copper-gold deposits have formed from I Ma to 2 Ga ago. Generally, they are related to the Mesozoic-Cenozoic interval with few reported occurrences from the Palaeozoic or Precambrian. A reason cited is the erosion of these deposits which are often related to convergent plate margins and orogenic belts. Observations of the alteration and mineralisation within and around porphyry copper/copper-gold systems have been included in numerous idealised models. These alteration and mineralisation patterns are dependent on the phases of intrusion, the tectonic setting and rock type, depth of emplacement and relationship to coeval volcanics, physiochemical conditions operative within and surrounding the intrusive and many other mechanical and geochemical conditions. Island arc and cratonic arc/margin deposits are generally considered to be richer in gold than their molybdenum-rich, intra-cratonic counterparts. Metal zonation may occur around these copper/copper-gold deposits, e.g. copper in the core moving out to silver, lead, zinc and gold. This zonation is not always present and gold may occur in the core, intermediate or distal zones. Examples of gold-rich porphyry deposits from British Columbia, Chile and the SW Pacific Island regions suggest gold is closely associated with the potassic-rich zones. Generally these gold-rich zones have greater than 2% magnetite and a high oxygen fugacity is considered to be an important control for gold deposition. High Cl contents within the magma are necessary for gold mobility within the host intrusive centres. Beyond this zone HS₂ becomes an important transporting ligand. Exploration for porphyry copper-gold deposits includes an integrated geological, geophysical and geochemical approach. Petrographic work through to Landsat imagery may be used to determine the chemical conditions of the system, ore association, favourable structural zones and alteration patterns, in order to focus exploration activities.
4
Sainath, Narayana Rangaiah 1968. "Dynamic behavior of flow during leaching of copper ores". Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/291737.
Testo completoAbstract (sommario):
The objective of this investigation was to experimentally determine the variation in the flow characteristics of tactite copper ores during the leaching process. The laboratory work involved estimation of porosity and permeability of cores before leaching, and after various intervals of leaching. The tests were carried out using specimens of diameter 1.5 and 4.0 inches, prepared from boulders obtained from the Cyprus Casa Grande mine. A solution containing about 25 grams of sulfuric acid per liter was used as the lixiviant. Porosity was determined using the water saturation method. The permeability was estimated using either helium or water with the specimens stressed triaxially to simulate in situ conditions. The rate of copper recovery from the specimen during the leaching process was also determined by estimating the copper content in the solution used for leaching. The results indicate that the permeability and porosity of the specimens increased with leaching, but both tend to remain constant after most of the soluble material in the core was dissolved. The rate of copper recovery was high initially but dropped as leaching progressed and the copper in the specimen was depleted.
5
Crane, Martin John, University of Western Sydney, of Science Technology and Environment College e of Science Food and Horticulture School. "Geochemical studies of selected base metal minerals from the supergene zone". THESIS_CSTE_SFH_Crane_M.xml, 2001. http://handle.uws.edu.au:8081/1959.7/232.
Testo completoAbstract (sommario):
Acid leaching of different natural chrysocolla samples under ambient conditions demonstrated that the chemical and chrystallographic inhomogenity significantly affects the rate and that it is virtually impossible to use the mineral as a model for the kinetics of hydrometallurgical processing of copper ores.Dissolution experiments, stability diagrams,and X-ray powder diffraction studies are undertaken and studied in this research and results are given.It is found that a complete solid solution series exists in Nature with most tungstenian wulfenites and molybdenum stolzites containing a range of compositions. The first occurrence of a molybdenum stolzite from Broken Hill, Australia, which also contains small amounts of chromium is noted.Raman microprobe spectroscopy has proven to be a very quick and effective non-destructive method for semi-quantitative analysis of the wulfenite-stolzite and powellite-scheelite solid-solution series and in detecting very small amounts of substituted chromate in wulfenite, stolzite and anglesiteDoctor of Philosophy (PhD)
6
Kamali, Mahtab. "Recovery of copper from low-grade ores by Aspergillus niger". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ64055.pdf.
Testo completo
7
Latorre, J. J. "Exploration for stratabound copper, lead and zinc deposits in the Damara-Katanga orogen, central-southern Africa". Thesis, Rhodes University, 1992. http://hdl.handle.net/10962/d1005558.
Testo completoAbstract (sommario):
The Damara-Katanga orogen in central-southern Africa represents an area of 1.73xl0⁶ sq. km. The region is considered one of the wealthiest metallogenic provinces in the world. Successful exploration for stratabound base-metal deposits has taken place at this particular area since the introduction of more organised methodology in the early 1920s. The genesis, location and distribution of the ore deposits are related to their tectonic settings. Geodynamic evolution of the orogen, which initially formed part of a complex Pan-African rift system, comprises the following stages rifting; downwarping, including spreading on the western portion; syn-orogeny and late-orogeny. Two major tectonic events in the history of the region have been identified: the Katangan (900-750 Ma) and the Damaran episodes (750-500 Ma). Timing of mineralisation of ore deposits has been related to the evolutionary stages of the orogen. Genetic models of the most productive deposits are briefly discussed in this dissertation. The sedimentological, geochemical, paleogeographic and structural features can be employed as geological guidelines for integrated exploration programmes. Discoveries of major deposits and prospects in the orogen are also summarised, focussing on the exploration methods employed. The cost-effective use of the exploration techniques includes the classical copper-lead-zinc soil sampling for residual soils such as those in the Copperbelt area. Airborne magnetics and electromagnetics and follow-up ground geophysics have proved successful in areas where the cover is transported in the search for shallow ore deposits such as the Matchless massive sulphides. Remote sensing, geochemical and geophysical techniques have been tried in covered areas of western Botswana. The lack of geological control makes this interpretation difficult. A detailed geological mapping and the use of geochemical and geophysical techniques has been used to delineate carbonate-hosted base-metal deposits at the Otavi Land. The more expensive traditional methods necessary for the delineation of orebodies, such as pitting, trenching and drilling, are also discussed. Using a sequential approach, a possible exploration strategy is suggested, outlining the cost-effective use of remote sensing, geochemical and geophysical techniques. Standardisation in basic geological information is required for future successful explorations in the Damara-Katanga orogen, as well as attractive mining policies. In the event of their implementation, exploration perspectives are promising, specifically in terms of ore potential.
8
Jiang, Mofen. "The Chemical and kinetic mechanism for leaching of chrysocolla by sulfuric acid". Thesis, The University of Arizona, 1992. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1992_610_sip1_w.pdf&type=application/pdf.
Testo completo
9
Légaré, Nathalie. "Les minéralisations de zinc-cuivre du secteur Frotet-Troilus, Chibougamau, Québec /". Thèse, Chicoutimi : Université du Québec à Chicoutimi, 2002. http://theses.uqac.ca.
Testo completo
10
Barriga, Vilca Abrahan. "Studies on the curing and leaching kinetics of mixed copper ores". Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44500.
Testo completoAbstract (sommario):
Heap leaching is a metal extraction process from low grade ores where crushed ore is stacked on an impermeable pad and irrigated from the top with a solution of chemical reagents. An enriched solution containing the targeted metal is collected at the bottom. This technique involves complex chemical/electrochemical reactions and transport processes. Among the main features of this method of extraction include low capital and operative cost, modularity, and relatively high inventory of solutions.
The need to optimize a heap operation has led to research studies in order to understand and interpret the chemistry and transport involved in a heap leach. These scientific investigations are focused on mathematical expressions of the reactions and transport phenomena of the minerals and reagents from the particle scale to the bulk scale. However, it was envisaged that pretreatment of these minerals are not accounted for in existing mathematical models of heap leaching. Sulfuric acid curing is a pretreatment to accelerate the extraction kinetics of copper ores and is widely used in copper operations. The curing process involves the addition of a highly concentrated sulfuric acid to the copper ore during agglomeration. Then, chemical reactions already begin prior to irrigation of the heap, transforming the initial copper species into new copper species which are easier to solubilize once the leach solution is provided to top of the heap.
The present study aims to provide a means for the systematic integration of the curing pretreatment and the subsequent leaching process. The numerical implementation of the model is done using the Matlab programming language. The focus of this curing and leaching model is to represent the leaching kinetics of each mineral species, which involves solution of a system of ordinary differential equations. The numerical parameters of the proposed curing and leaching kinetic model were found from a set of laboratory experiments. Additionally, novel methods for determining the optimum agglomeration moisture, the optimum sulfuric acid dose for acid curing, and the relevant solute transport parameters were employed. The resulting model can be applied for design, scale-up, and optimization of a new or existing commercial heap leach operation.
11
Hangone, Gregory. "The role of collectors in the flotation of partially oxidised copper ores". Thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/6730.
Testo completoAbstract (sommario):
The effects of xanthates, dithiophosphates, dithiocarbamates and mixtures of these collectors on the froth flotation performance of partially oxidised and oxidised copper sulphide ores were investigated in this study. More specifically, the role of the functional groups of the collectors, their dosages and the effect of collector mixtures and their dosages were investigated. Batch flotation tests were used to assess the performance in terms of mass-water recovery, sulphur grade-recovery, copper grade-recovery and acid soluble copper grade-recovery relationships and the Klimpel rate constant for copper recovery. Flotation characteristics of bornite rich Carolusberg copper sulphide ore from Okiep Copper Company (1.8% copper) and bornite and chalcopyrite rich ore from Palaborwa Mining Company (0.58% copper) were compared.
12
Zheng, Jialong. "An electrochemical study of the copper-gold-cyanide system with reference to the processing of copper-gold ores". Thesis, Zheng, Jialong (2000) An electrochemical study of the copper-gold-cyanide system with reference to the processing of copper-gold ores. PhD thesis, Murdoch University, 2000. https://researchrepository.murdoch.edu.au/id/eprint/52721/.
Testo completoAbstract (sommario):
Gold and copper often occur together in ores, an occurrence which creates processing difficulties since cyanide leach solutions are not selective for gold. Copper contamination can result in serious problems throughout the conventional carbon-inpulp process, often making the operation uneconomic.
This thesis describes electrochemical studies of two ways of dealing with copper contamination. One concerns the selective electrodeposition of gold from coppercontaining cyanide solutions; the second concerns the possibility of selectively leaching gold from copper-containing ores using an aerated ammoniacal cyanide solution.
In the electrowinning study, a rotating disc electrode technique was combined with a method of chemical analysis to investigate the codeposition behaviour of copper and gold. In these experiments, the variables were gold concentration, agitation, free cyanide concentration, pH and temperature. The experimental results obtained have provided an improved understanding of the electrolytic codeposition of copper with gold in cyanide solutions. The major factors influencing copper codeposition with gold are the free cyanide concentration, the operating temperature and the pH of the electrowinning solution. By controlling these variables in the electrowinning operation, it is possible to minimise the copper deposition.
Pulsed potential control was employed as an alternative to constant potential electrodeposition as a means of reducing copper codeposition in the gold electrowinning process. It was demonstrated in this work that by simply varying the parameters of the applied pulsed potential waveform, all other operating conditions being the same as for the constant potential case, copper contamination was greatly reduced. This improvement is due to the high instantaneous gold deposition rate during the cathodic potential pulse period and the copper redissolution during the anodic potential pulse period.
A rotating electrochemical quartz crystal microbalance (REQCM) technique was developed in this research work. It was demonstrated that this REQCM technique is capable of measuring the partial current of a metal deposition in the potential region where the hydrogen evolution reaction is involved.. Thus, obtaining information outside the electrochemical window of a solid electrode become possible. The REQCM was used to study the mechanism of copper and gold deposition from cyanide solution.
One of the findings from this work is that when using the chronopotentiometric method to study metal dissolution or cementation reactions, the effect of the inert substrate must be taken into account. It was found that the substrate has no influence on the rate if the reaction is diffusion controlled; however, it markedly affects the rate of chemically controlled reactions. The magnitude of the effect is related to the catalytic activity of the substrate.
The REQCM technique was also used to study the mechanism of selective leaching of gold from copper contaminated ores using ammoniacal cyanide. Experimental results show that in copper containing cyanide solutions, the copper-cyanide complex species takes part in the gold dissolution reaction. The addition of ammonia to solutions containing copper and cyanide greatly diminishes the rate of gold dissolution. However, when the cyanide to copper ratio is close to 2:1, the rate of gold dissolution increases on addition of ammonia. This may be due to the formation of some goldammonia complex or the involvement of the formation of Cu(II)- cyanide-ammonia complex which can act as an oxidant in the gold leaching process.
13
Chen, Wei, e 陈伟. "Origin and tectonic environment of the Lala Fe-Cu-(Mo, REE) deposit, Sichuan province, SW China". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/197093.
Testo completoAbstract (sommario):
The Hekou Group in the Kangdian region, SW Yangtze Block is a metavolcanic-metasedimentary succession hosting the giant Lala Fe-Cu-(Mo, REE) deposit. Mafic volcanic rocks of the Hekou Group and nearby gabbroic intrusions have identical zircon U-Pb ages of ~1700 Ma. The sedimentary and mafic rocks are suggested to have formed in an intra-continental rift, similar to those of the North Australian Craton. Such a similarity suggests that the Yangtze Block was likely linked with the North Australian Craton in the Columbia supercontinent during late Paleoproterozoic.
Overlying the Hekou Group is a thick sedimentary sequence of the Julin Group containing basaltic layers with zircon U-Pb ages of ~1050 Ma. The basalts and other coeval igneous rocks in the region have geochemical affinity of within-plate rocks, representing a ~1.05-1.1 Ga rifting event. Occurrence of the within-plate rocks does not support existence of a Grenvillian orogenic belt in the region, and thus agrues against previous hypothesis that proposed the Yangtze Block to be located in the interior of the Rodinia supercontinent on the basis of the so-called Grenvillian orogenic belt.
The Lala deposit contains 200 Mt of ores with an average grade of 13 wt.% Fe, 0.92 wt.% Cu, 0.018 wt.% Mo, 0.022 wt.% Co, 0.25 wt.% REE2O3 and 0.16 ppm Au, and is one of the largest IOCG deposits in the region. The ores are hosted mostly in meta-vocalnic rocks (albitite) and schists, and are characterized by abundant low-Ti magnetite with subordinate chalcopyrite, pyrite, molybdenite and REE minerals. The paragenetic sequence includes Stage I of Na-alteration, Stage II of Fe mineralization, Stage III of Cu-Mo-REE mineralization, Stage IV of chalcopyrite-pyrite-calcite veins and Stage V of hematite-calcite-quartz veins. Molybdenite of Stage III has a Re-Os isotopic age of 1086 ± 8 Ma, similar to U-Pb ages of the primary allanite as 1067 ± 41 Ma, suggesting that mineralization of the Lala deposit is coeval with the ~1.05-1.1 Ga within-plate magmatism in the region. The secondary allanite has U-Pb ages of 880-850 Ma, comparable to Ar-Ar and Pb-Pb ages of undeformed Stage IV and V veins, representing a younger hydrothermal event.
C-O-S isotopes suggest that the Fe and Cu mineralization stages (II and III) at Lala have formed from high temperature magmatic-hydrothermal fluids (385-430ºC). However, compositions of fluid inclusions and minerals demonstrate that the Fe and Cu mineralizing fluids have different compositions. Strontium isotopic compositions of apatite and calcite suggest that the Fe mineralizing fluid has formed from magmatic fluids interacted with late Paleoproterozoic host rocks, whereas the Cu mineralizing fluid with much higher 87Sr/86Sr ratios has possibly involved magmatic fluids that have interacted with older basement beneath. Close association of monazite-bearing apatite, Cu-sulfides and REE-minerals at Lala suggests that REE mobilization and mineralization is genetically related to the Cu mineralizing fluid. This study suggests that the Cu mineralizing fluid contains Cl-, K, CO2, F-, PO43- and CO32- with low Na activity, and is thus responsible for mobilization, transportation and deposition of LREEs in the Lala deposit.published_or_final_version
Earth Sciences
Doctoral
Doctor of Philosophy
14
Giovenazzo, Danielle. "Géologie et caractéristiques géochimiques des minéralisations Ni-Cu-EGP de la région de Delta, ceinture de Cape-Smith, Nouveau-Québec /". Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1991. http://theses.uqac.ca.
Testo completo
15
Zhao, Xinfu. "Paleoproterozoic crustal evolution and Fe-Cu metallogeny of the western Yangtze Block, SW China". Click to view the E-thesis via HKUTO, 2010. http://sunzi.lib.hku.hk/hkuto/record/B43572261.
Testo completo
16
Magnan, Martin. "La zone 87 du gisement d'or et de cuivre du lac Troilus : pétrographie et géochimie /". Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1993. http://theses.uqac.ca.
Testo completo
17
Tanda, Bennson Chemuta. "Glycine as a lixiviant for the leaching of low grade copper-gold ores". Thesis, Curtin University, 2017. http://hdl.handle.net/20.500.11937/56525.
Testo completoAbstract (sommario):
The continuous depletion of high grade gold ores has shifted research focus towards the processing of low grade, complex ores containing impurities such as copper which is detrimental to the traditional cyanidation process.
Alkaline glycine solution selectively leached copper and gold over impurity elements such as Fe, Ca, Mg and Si from copper – gold ores. Copper was recovered from solution by solvent extraction and gold could be recovered by carbon adsorption while glycine is recycled.
18
Mach, Craig J. "Tectonic controls, timing and geochemistry of supergene enrichment of the Tyrone porphyry copper deposit, Grant County, New Mexico /". abstract and full text PDF (UNR users only), 2009. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3342621.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of Nevada, Reno, 2008."December, 2008." Accompanying CD-ROM contains appendices C and D. Appendix C: AutoCAD files with drill hole log; Appendix D: excel spreadsheet with copper mass balance calculations. Includes bibliographical references (leaves 206-215). Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2009]. 1 microfilm reel ; 35 mm. Online version available on the World Wide Web.
19
Rusk, Brian Geoffrey. "Cathodoluminescent quartz textures and fluid inclusions in veins of the porphyry copper-molybdenum deposit in Butte, Montana : constraints on physical and chemical evolution of the hydrothermal system /". view abstract or download file of text, 2003. http://wwwlib.umi.com/cr/uoregon/fullcit?p3080595.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of Oregon, 2003.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 211-235). Also available for download via the World Wide Web; free to University of Oregon users.
20
Crane, Martin John. "Geochemical studies of selected base metal minerals from supergene zone /". View thesis, 2001. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030721.132607/index.html.
Testo completoAbstract (sommario):
Thesis (PhD) -- University of Western Sdyney, 2001."A thesis presented in accordance with the regulations governing the award of the degree of Doctor of Philosophy, University of Western Sydney" "November 2001" Bibliography: leaves 249 - 254.
21
Diaz, Acevedo Nelson Simon. "Exotic deposits derived from porphyry copper systems in Chile". Thesis, Rhodes University, 1996. http://hdl.handle.net/10962/d1011149.
Testo completoAbstract (sommario):
The exotic orebodies related to cal-alkaline porphyry copper deposits. are sub-horizontal lenticular bodies of secondary copper minerals that impregnate Tertiary gravels and bedrock of different ages. They lie immediately downslope of the porphyry copper deposits, that is to say. they are related to the propylitic halo of the main deposits, and are considered to have originated with the deposition of copper minerals from solutions that overflowed during the secondary enrichment process. Supergene alteration took place between the late Oligocene and Miocene, by which time both orehodies (exotic and porphyry copper) were established. The paucity of tile denudation since the Miocene in the Andean segment from 21º to 26º latitude S. due to the dominance of a hyperarid climate explains the remarkable preservation of the shallow porphyry copper systems, supergene enriched blankets and associated deposits. This is reflected in the limonites, where the typical boxworks have been partially or totally destroyed on surface by the superleaching. As a result of the lateral migration of the copper-bearing solutions, the exotic deposits show a zonation. alteration and mineralization whose characteristics depend among other factors. on the reactivity of the bedrocks and the Cu/S ratio of the mother deposit. In these deposits three zones can be recognized: Proximal (0 to 2 km Intermediate (2 to 3) and Distal (3 to 8-14 km) with palaeodrainage control. The associations and mineralogical abundance are related to the climate (rain. temperature). In some deposits two important units are detected and they are the Cu-phosphates and Cu-lixiviable (to sulphuric acid) units. The size of tile Chilean exotic deposits varies between 100 and 3.500.000 tons of copper, with a total known resource of 8 M tons of copper. The large exotic deposits are comparable to the resources of a medium-sized porphyry copper- type deposit. The discovery of the exotic deposits is related to the exploration of porphyry copper deposits, where a mass balance of the leached column must be done. Moreover the lithology and alteration of the propylitic halo. permeability, structures, geophysics and geochemistry should be considered. The diorite model is not compatible with a supergene enrichment process, expressed by the absence of colour anomalies, exotic deposits and in the presence of secondary minerals like jarosite, which is coherent with the pyrite deficiency of the system. The projects are for exploitation of reserves by open pit methods. The projects plan to extract and to crush copper oxide ore which will he pre-treated with concentrated sulphuric acid prior to heap leaching, solvent extraction and electrowinning. The copper output varies between 10,000 and 50,000 ton per year of catilode copper. The total investment varies between 20 and 100 millions dollars. For project calculations, estimation of 65 % - 82 % copper recovery and 37 - 40 kg/ton net acid consumption can be used due to the nature of ore. The leaching time is estimated as 30 to 180 days for heaps of 4,5 to 30 metres high. As a result of this, the plant capacity is determined by an annual equivalent of 10,000 to 25,000 ton Cu per year. Pit planning has heen carried out using diverse software on the basis of 5 x 5 x 5 m and 10 x 10 x 10 m block models, evaluated using a kriging package built into the program, giving an overall waste/ore ratio (induding pre-stripping) of 0: I (in an outcrop) to 3: I. The location of the mine and plant sites are associated with the porphyry copper in production, for this the already installed facilities can be used. So there is no need to build a new mine camp or access. The environmental impact is summarized relating to the characterization of the physical, biological and socio-cuitural effects, using the framework of the Base Line study and the Impact evaluation derived from the construction and project operation phases. The conclusions and recommendations will diminish, mitigate and/or eliminate impact derived from the specific activities.
22
Sapiie, Benyamin. "Strike-slip faulting, breccia formation and porphyry Cu-Au mineralization in the Gunung Bijih (Ertsberg) mining district, Irian Jaya, Indonesia /". Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of Texas at Austin, 1998.Vita. Four folded plates in pocket. Includes bibliographical references (leaves 285-303). Available also in a digital version from Dissertation Abstracts.
23
Korkalo, T. (Tuomo). "Gold and copper deposits in Central Lapland, Northern Finland, with special reference to their exploration and exploitation". Doctoral thesis, University of Oulu, 2006. http://urn.fi/urn:isbn:951428108X.
Testo completoAbstract (sommario):
Abstract
At least 30 gold deposits verified by means of one or more notable diamond drill hole results have been discovered in Central Lapland in the last 20 years, and these can be divided spatially into groups, between which the metal composition varies. The deposits contain varying amounts of sulphides and sulpharsenides as well as gold. Pyrite is the most common sulphide mineral in the gold deposits associated with volcanic rocks, and usually pyrrhotite in those associated with sedimentary rocks. The principal sulphide minerals in those connected with banded iron formations are pyrite and arsenopyrite. A separate group of formations consists of the palaeoplacer gold deposits associated with the molasse-like quartzites and conglomerates of Central Lapland.
The iron oxide-copper-gold deposits of Central Lapland, which are a significant potential source of copper and gold, are mostly associated with skarn rocks at the eastern contact of the acidic intrusive rocks of Western Lapland and with skarn rocks occurring as interlayers in metavolcanic and metasedimentary rocks.
The gold deposits that have led to actual mining activities in Central Lapland are Saattopora in Kittilä and Pahtavaara in Sodankylä. Apart from the Laurinoja iron oxide-copper-gold ore body in Kolari, copper concentrate has been produced from the Saattopora gold ore deposit and the Pahtavuoma copper ore deposit. Only one gold ore in Central Lapland is being actively exploited at present, that of the Pahtavaara mine, which was worked in 1995–2000 and reopened in 2003.
The best starting point for successful gold ore exploration in Central Lapland can be achieved through a thorough knowledge of the deformation zones and their structures and alteration processes and the application of geochemical methods. Magnetic surveys can be of help in identifying and locating deformation zones of interest for exploration purposes and the majority of the associated shear zones and faults. Ore-critical zones usually feature graphite-bearing schists and iron sulphide-bearing sequences that can be traced by electrical methods and used as marker zones to verify the results of geological mapping. Geological, geophysical and geochemical techniques have been used in great diversity, and in particular till geochemistry and bedrock drilling have been methods by which the gold and copper deposits in Central Lapland have been discovered.
A total of 7.6 million tonnes of gold and copper ores, including the Laurinoja iron oxide-copper-gold ore, were extracted in Central Lapland over the period 1982–2000. The resulting production of gold during this period was 10 800 kg, together with 21 000 tonnes of copper in concentrates and 4500 kg of silver.
The gold and copper ores have been concentrated by gravity separation and/or flotation, since the ores so far taken into production has been of the free milling type. However, a substantial proportion of the deposits in the area contain copper, nickel, cobalt and arsenic as well, in the form of sulphides or sulpharsenides, so that the achievement of commercially saleable products calls for the use of different leaching processes. Deposits have also been found in Central Lapland that have consisted partly or entirely of refractory gold ore in which gold is lying in the crystal lattice of pyrite and/or arsenopyrite, the processing of which by the above-mentioned methods is not economic, as it requires pre-treatment by bio-oxidation or pressure oxidation in order to convert the gold to a cyanide-soluble form.
24
Shah, Kush. "The use of surfactants to aid and improve the leaching of low grade copper ores". Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/61802.
Testo completoAbstract (sommario):
Copper heap leach operations often suffer from reduced efficiency due to long leach times and variable recoveries. Surfactants have been considered as an option in increasing the leachability of ores. Improvements in overall copper extraction have been noted with their use, though testing has only been conducted on a limited scale. The molecular function of surfactants in heap leaching has not been extensively studied and is not well explored. The work in this thesis was aimed at better understanding and characterizing the function of the surfactants. Work was performed with surfactants developed by BASF specifically for heap leaching.
Initial experimentation consisted of using flooded vats to compare copper extraction from ores. Leach solution with and without surfactant was fed to the ores. The presence of surfactants was noted to increase the overall copper recovered by approximately 2-3%. Interfacial tension measurements were performed to determine the changes imparted onto the acidic leach solution by the surfactants. Hanging drops were used to determine the activity at the air-liquid boundary. It was found that at the surfactant concentrations used in heap leaching, the interfacial tension of the fluid changed very little, from about 71 mN/m to 69.5 mN/m.
The contact angle was determined to better understand the interaction between the acidic media and the ore. This was obtained using capillary wicking and Washburn’s equation. Ore was finely ground and packed into particle beds. Leach liquid with surfactant was introduced to these beds. The rate of permeating fluid flow was monitored against time. The affinity of the liquid for the solid surface dictated the rate of uptake. Washburn’s equation allowed for the contact angle to be calculated from these results. It was found that surfactants lowered the contact angle of liquid on solid by up to 3 degrees.
The combination of results indicated that the surfactants increases the affinity between the solid and liquid by reducing the contact angle. In a heap, this allows acid to ingress further into sub-surface regions of ore particles. As a result, leachability of the ore is increased as harder to reach minerals can be accessed.Applied Science, Faculty of
Materials Engineering, Department of
Graduate
25
Ackerman, Benjamin R. "Regolith geochemical exploration in the Girilambone District of New South Wales". Access electronically, 2005. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20051027.095334/index.html.
Testo completo
26
Ure, Alexander David. "Understanding the influence of mineralogy and microwave energy input on the microwave treatment of copper ores". Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/41513/.
Testo completoAbstract (sommario):
Ore comminution is an energy intensive and inefficient process in which new innovative technologies could potentially deliver great benefits. Over the past two decades, the high power microwave treatment of ores has shown the potential of being a novel step-changing comminution technology. The ability of microwaves to rapidly and selectively heat certain minerals within an ore, and generate and propagate intergranular fractures at grain boundaries, has been shown to be an innovative process for reducing ore strength and enhancing mineral liberation. A review of the literature has identified that, while the understanding of the process has developed significantly over recent years, fundamental knowledge of how mineralogical characteristics of different ores influences their amenability to microwave treatment is still limited. Previous work in this field has also been primarily concerned with assessing the downstream mineral processing benefits achievable, rather than directly measuring the impact of the treatment on ore fracturing. The aim of this experimental investigation has been to make an original and distinct contribution towards the current state of knowledge, through the application of innovative microwave treatment processes and conventional and novel analytical methods. Three copper ore samples, termed MZ, QZ and QX, were assessed following a series of microwave treatments at unprecedented conditions, for changes in Cu-sulphide mineral liberation using automated mineralogy, and changes in ore comminution using JK GeM Crushing Index and Bond Ball Mill Work Index testing methods. A novel fracture analysis and quantification method was also developed and applied for the first time to the assessment of microwave treated ores. MZ and QZ ores achieved similar improvements in Cu-sulphide mineral liberation and comminution performance following microwave treatment, as it has been shown from coarse ore characterisation that both ores possess characteristics that render them highly amenable to beneficial microwave treatment outcomes. This finding validates ore amenability characteristics proposed by previous researchers. Fracture analysis results have quantifiably shown for the first time that microwave treatments can induce additional beneficial fracturing in amenable ores. An additional original contribution to the field is that beneficial fracture outcomes were shown to correspond with benefits achieved in Cu-sulphide liberation, and ore comminution testing. Investigations were also conducted to determine the minimum microwave energy input threshold at which measurable benefits in ore comminution and mineral liberation are achievable. Following an additional series of unprecedentedly low dose microwave treatments of MZ ore, it was observed that benefits in Cu-sulphide mineral liberation can be achieved from microwave treatment with a power density of 2.0x106W/m3 and a total microwave energy input of 0.3kWh/t, at an applicator residence duration of ~0.25 seconds. Treatment conditions for total microwave energy input at which benefits have been shown to be achievable, are lower than conditions previously reported in the literature for any ore type. This outcome indicates that scale-up of the process to industrially relevant throughputs (i.e. >10,000 t/h) could potentially be achieved using existing microwave generator technology, eliminating the need for the development of higher power generators producing over 100kW of microwave power. Conclusions from this experimental investigation have provided an original contribution to the fundamental knowledge of the microwave treatment of copper ores, and have advanced the understanding of the application of the process to enhancing mineral liberation and ore comminution. Further investigations of a range of amenable copper ores, or ores of different commodities, at low microwave treatment doses of 0.3-0.7kWh/t would allow for an assessment of whether this newly determined minimum energy threshold at which mineral processing benefits have been shown, also applies to ores with different mineralogical and textural characteristics.
27
Thériault, Robert. "Influence de l'assimilation de roches sédimentaires encaissantes sur l'origine des gisements de Cu-Ni-EGP de l'intrusion de Partridge River, complexe de Duluth, Minnesota /". Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1999. http://theses.uqac.ca.
Testo completo
28
Scott, Grant. "Microwave pretreatment of a low grade copper ore to enhance milling performance and liberation". Thesis, Link to the online version, 2006. http://hdl.handle.net/10019/123.
Testo completo
29
Amos, Idzi Ambo. "Chemical investigation of leaching and electrochemical behaviour of sensor-based pre-concentrated copper ores with alkaline lixiviant". Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/20849.
Testo completoAbstract (sommario):
While the production of copper metal from primary ores is still increasing, the gradual depletion of high-grade ores implies that the recovery of the metal from low-grade ores is presenting a challenge. A major problem associated with processing of low-grade copper ores can be their high calcite content and concentration of other metals such as Fe, Mn, Co, As, Pb, and Ni. These other metals make the processing of such ores expensive due to the high cost of the leaching chemicals. Therefore, in this study a novel, integrated copper processing method is developed to enhance the economic extraction of copper from such ores. This research investigated the chemical leaching behaviour of porphyry copper ore samples from Chile, South America. Ores were pre-concentrated and classified with near infrared sensing into product, middling and waste fractions. Mineralogical analysis of the ore was conducted using QEMSCAN®, XRD and NIR. The elemental investigation of the ore was carried out using PXRF, ICP-MS and SEM. Analyses revealed that the major copper-bearing mineral is chrysocolla and that the ore is composed mainly of silicate, oxide and carbonate gangue. Calcite in the ore is considered problematic due to acid consumption. In terms of abundance of gangue in the classified ore the order is waste > middling and product. A systematic comparison of the complexometric behaviour of the ore was investigated with Na2EDTA reagent while the leaching behaviour of the classified ore was investigated in NH4Cl and H2C2O4 lixiviants. The influence of process variables such as lixiviant concentrations, particle sizes, solid-to-liquid ratio, temperature, time and stirring speed on the behaviour of the classified ore were investigated. The rate of Cu dissolution and formation of Cu-EDTA complex in Na2EDTA was higher in the product than the middling while that of the waste was found to be insignificant at 0.01 M, even when the concentration of the complexing agent was increased from 0.01 M to 0.05 M. The rate of Cu-EDTA complex formation was found to increase with decreasing particle sizes and solid-to-liquid ratio across the ore categories. Ammonium chloride leaching of the product and middling revealed contrasting behaviour. The rate of Cu extraction was found to increase significantly from 21.5 % to 75.0 % and 27.3 % to 89.0 % when the temperature was increased from 40 ˚C to 90 ˚C, respectively. On increasing the concentration of NH4Cl from 0.5 M to 5 M, the extraction of Cu was found to increase from 20.0 % to 65.0 % and 26.5% to 83.3 %, respectively. It was found that the leaching yield of Cu increased substantially when the particle size was decreased from –125+90 μm to –90+63 μm and –63+45 μm and with decreasing solid-to-liquid ratio (middling and product), respectively. A steady decrease in Cu extraction was obtained when the stirring speed was increased from 300 rpm to 800 rpm. Similarly, the effectiveness of the leaching process was investigated over an extended time period from 2 h to 4 h with an NH4Cl concentration range of 0.55 M to 1.65 M, a temperature of 70 ˚C to 90 ˚C, and at a constant stirring speed of 300 rpm, particle size fraction of -64+45 μm and a solid to liquid volume of 6 g/ 250 mL. It was found that Cu extraction was enhanced by about 90 % during the experiment. The estimated activation energy of the leaching process was characterized using the shrinking core model under the experimental conditions. It was found to range between 45 and 71 KJ/mol in the first and second batch experiments, which is indicative of a chemically controlled leach process. XRD and ICP-MS characterization of mineralogical and chemical composition of residues suggested that the NH4Cl lixiviant leaching is selective for Cu. Examination of leachate with ICP-MS for co-extraction of Mn, Co, Ni and Zn indicated insignificant solubilisation of the metals during leaching. Comparison of Cu extraction in NH4Cl and H2C2O4 under the same experimental conditions revealed that NH4Cl is a better extractant than H2C2O4. Furthermore, the electrodeposition of Cu metal was studied with ore leachate containing Cu(NH3)42+ complexes and with Cu(NH3)4SO4 synthetic electrolyte. Cyclic voltammetric measurements were conducted across a range of cathodic potentials from 0.8 V to – 1.0 V for selected scan rates of 20, 30, 50, 100 and 200 mV/s. Chemical reduction and electrodeposition of Cu from the complexes was found to proceed via two reversible electrochemical processes, each involving the transfer of a single electron. Cu(NH3)42+ complexes are first reduced to Cu(NH3)2+, which is in turn reduced to metallic Cu. The result is compared with the behaviour of synthetic Cu(NH3)4SO4 electrolyte. It was observed that the reduction of Cu(NH3)4SO4 to metallic Cu proceeds as two sequential, single electron transfer processes. The Cu/Cu(NH3)42+ redox reaction was observed to be fast compared to Cu/Cu2+ redox reaction in the Cu(NH3)4SO4 solution. Investigation of the electrochemical kinetics shows that the cathodic peak current varied linearly with the square root of the scan rate, which is indicative of the Cu(NH3)2+ and Cu(NH3)4SO4 reduction to Cu proceeding through a diffusion-controlled process. Assessment of the effect of calcite for leaching of copper from classified ore fractions indicated the potential of NH4Cl lixiviant for the leaching application. Three processing routes to handle the ore fractions on the basis of variation in calcite, gangue and copper content are proposed.
30
Cartwright, John Alexander. "Study of the leaching of polymetallic sulphide ores using ion selective membranes". Thesis, Queensland University of Technology, 1998.
Cerca il testo completo
31
Rickard, Jason H. "Petrological and mineralogical study of Cu-Ni-PGE-bearing ores within the 100 orebody, Copper Cliff North mine, Sudbury, Ontario". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0012/MQ52404.pdf.
Testo completo
32
Rickard, Jason H. Carleton University Dissertation Earth Sciences. "Petrological and mineralogical study of Cu-Ni-PGE-bearing ores within the 100 orebody, Copper Cliff North mine, Sudbury, Ontario". Ottawa, 2000.
Cerca il testo completo
33
Tremblay, Christian. "Les éléments du groupe du Platine dans le dyke de Méquillon ceinture de Cape-Smith, Nouveau-Québec /". Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1990. http://theses.uqac.ca.
Testo completo
34
Greentree, Matthew Richard. "Tectonostratigraphic analysis of the Proterozoic Kangdian iron oxide - copper province, South-West China". University of Western Australia. Tectonics Special Research Centre, 2007. http://theses.library.uwa.edu.au/adt-WU2009.0054.
Testo completoAbstract (sommario):
The Cenozoic Ailaoshan Red River shear zone marks the present day western margin of the South China Block. Along this margin are well preserved late Paleoproterozoic to early Neoproterozoic sedimentary and volcanic successions. This work examines the ages and tectonic environments for the formation of the successions, as well as significance of the regional tectono-magmatic events on the formation of widespread iron oxide-copper deposits. The oldest succession is the Paleoproterozoic Dahongshan Group. A new SHRIMP UPb age of 1675 ± 8 Ma for a tuffaceous schist unit confirms its Paleoproterozoic age. Detrital zircon ages of the Dahongshan Group range between Archean to Paleoproterozoic (ca. 2780 1860 Ma). They include a population of ca. 2400 2100 Ma grains, which have no known source region on the exposed Yangtze Block. Previous geochemical studies of metavolcanic rocks from the Dahongshan Group have suggested that these rocks were erupted in an oceanic setting. However, this study shows that the metavolcanics are extremely altered and cannot be used for reliable tectonic discrimination. Based on the characteristics of sedimentary rocks in the Dahongshan Group, it is suggested that these rocks were deposited in a continental setting. Overlying the Dahongshan Group is a thick sedimentary sequence which has been variably termed the Kunyang, Dongchuan, Huili or Xide Groups. In the past, these rocks have been considered as a Mesoproterozoic rift succession. However, no precise age constraints were available for the succession. In this study, this sequence is found to contain at least two separate tectonostratigraphic units. The oldest (ca.1140 Ma) is comprised of alkaline basalt with a geochemical and isotopic character similar to that of modern intracontinental rift basalts. The presence of Cathaysia-derived sediments in this unit indicates sedimentary transportation from the southerly Cathaysia Block to the northerly Yangtze Block (in present coordinates) in South China at that time, which suggests an impactogen scenario. The thick sedimentary sequence of what has traditionally been defined as the Kunyang Group has been found to have significantly younger depositional age of ca.1000 960 Ma. The composition of sedimentary rocks and the provenance of detrital zircons from the Kunyang Group are consistent with a foreland basin setting. The depositional age of this sequence coincides with the timing of Sibao Orogeny as determined elsewhere in the South China Block. Summary Page ii Numerous iron oxide - copper (gold) deposits occur within the rocks of the Dahongshan and Kunyang Groups. Previous studies have classified these deposits into two deposit styles: the Dahongshan-type Paleoproterozoic VMS mineralisation hosted within the Dahongshan Group, and the Dongchuan-type diagenetic carbonate and shale-hosted deposits hosted within the Kunyang Group. However, both deposit types share similarities with the iron oxide copper (gold) deposit class, such as stratabound disseminated and massive copper ores, abundance of iron oxide occurring mostly as low Ti - magnetite and haematite, and variable enrichments in Au, Ag, Co, F, Mo, P and REE. 40Ar/39Ar data from both deposit types indicate mineralisation ages of ca. 850 830 Ma and 780 740 Ma.
35
Rojas, Ricardo Vicente 1951. "ORE-WASTE SELECTION UTILIZING GEOSTATISTICS (ARIZONA)". Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/291255.
Testo completo
36
Gebert, James 1962. "The metallogeny of Cu-Ni and Zn-Cu-Pb deposits of the Frederickson Lake area, central Labrador Trough /". Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63942.
Testo completo
37
Zhao, Xinfu, e 赵新福. "Paleoproterozoic crustal evolution and Fe-Cu metallogeny of the western Yangtze Block, SW China". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B43572261.
Testo completo
38
Mhangara, Paidamwoyo. "Testing the ability of ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) to map hydrothermal alteration zones : a case study of the Haib Porphyry Copper-Molybdenum Deposit, Namibia". Thesis, Stellenbosch : Stellenbosch University, 2005. http://hdl.handle.net/10019.1/50462.
Testo completoAbstract (sommario):
Thesis (MSc)--Stellenbosch University, 2005.ENGLISH ABSTRACT: The availability of multispectral data from the satellite-borne ASTER (Advanced Space borne Thermal Emission Reflection Radiometer) sensor with 14 spectral bands, launched on 18 December 1999, ushers in a new dimension in large-scale mineral exploration. The ASTER bands are strategically positioned to map distinctive absorptive features for mapping alteration mineralogy, which has increased the potential to map hydrothermal alteration zones as compared to the conventional Landsat TM satellite and aerial photographs. This research tests the ability of ASTER to map hydrothermal alteration zones by applying various image enhancement techniques and comparing them. The study area is the Haib copper prospect in Namibia. The Crosta technique, standard colour composites, spectral band ratioing, the software defoliant technique, log residuals and spectral linear unmixing were applied and compared against results from the previous detailed geophysical and geochemical exploration. The results from all the techniques corresponded with published geological maps from previous work and indicated ASTER's ability to detect alteration zonations. Comparison of the methods applied showed that choice of technique is usually dependent of the level of detail which one seeks to achieve. Standard colour composite and log residuals are more useful for a generalized overview of the alteration mineralogy, whilst uniquely defining mineral end members is achieved by application of the Crosta technique, ratioing and spectral linear unmixing. Application of the software defoliant techniques involved ratioing results, which are affected by spectral interferences from other minerals. The presence of a highly fractured system has been established by application of Sobel filtering. A spatial association of the extracted fracture system with alteration areas suggest mineralization at the Haib is fracture controlled. The results support the presence of argillicphyllic and prophylitic alteration zones on a regional scale, a scenario which can be equated to the Lowell-Guilbert model. The potassic-phyllic zone boundary could not be spectrally detected which also supports previous studies which suggest the potassic zone is nondefinitive and is over-printed by the phyllic zone. The results demonstrate that ASTER is an effective tool to map hydrothermal alteration systems in arid areas.
AFRIKAANSE OPSOMMING: Multispektrale data van die ASTER (' Advanced Space Borne Thermal Emmission Reflection Radiometer') sensors bestaande uit 14 spektrale bande, afkomstig van 'n satelliet gelanseer op 18 Desember 1999 lui 'n nuwe era in vir grootskaalse minerale eksplorasie. Die ASTER bande is strategies sodanig op die spektrum geposisioneer om onderskeidende absorberende verskynsels van veranderde mineralisasie te identifiseer. Hierdie data het die potensiaal verhoog om hidrotermale veranderingstelsels meer suksesvol te karteer as met konvensionele Landsat TM beelde en lugfotos. Hierdie navorsing toets die vermoeëns van ASTER om hidrotermale veranderingstelsels te karteer deur 'n wye reeks beeldverrykings tegnieke toe te pas en te vergelyk. Die studiegebied IS die Haib koperafsetting in Namibië. Die Crosta tegniek, standaard kleursamestellings ('colour composites'), ratio-tegnieke, plantegroeistroping ('software defoiliant'), log residuele ('log residual '), en spektrale lineêre ontmenging ('spectral linear unmixing') is toegepas en die resultate met vorige gedetailleerde geofisiese en geo-chemiese veldopnames te vergelyk. Die verkreë resultate van al die verskillende tegnieke het grootliks met gepubliseerde geologiese kaarte van die gebied ooreengestem en bevestig dat ASTER data geskik is om sulke mineralogies veranderde gebiede te karteer. Vergelykings tussen die tegnieke het getoon dat die keuse van tegniek bepaal word deur die vlak en tipe detail wat verlang word. Standaard kleursamestellings en die log residuele tegnieke lewer goeie resultate om veralgemeende oorsigte van mineralogies veranderde sones te verskaf, terwyl die Crosta-, ratio- en spektrale lineêre ontmengingstegnieke meer suksesvol is om spesifieke minerale te identifiseer. Die plantegroei stropingtegniek is nodig in gevalle waar spektrale ratios deur plantegroeiresponse geaffekeer word. Die aanwesigheid van 'n intensief gefraktuurde sisteem is bepaal deur 'n Sobel filter toe te pas. Ruimtelike assosiasies tussen die voorkoms van die gefraktuurde sone met en die minealogies gewysigde sones dui aan dat mineralogiese wysiging in die Haib gebied deur frakturering beheer is. Die resultate steun die aanwesigheid van argillities-fillitiese enpropolities gewysigde sones op 'n streekskaal, 'n scenario wat deur die Lowell-Guilbertmodel voorgehou word. Die grense van die kalium-fillitiese sone kon nie spektraal waargeneem word nie. Dit steun ook vorige studies wat suggereer dat die kaliumsone nieafbakenbaar is en waarskynlik deur die fillitiese sone oorlê word. Die resultate bevestig onomwonde dat ASTER data benut kan word om hidrotermaal veranderde sones in semiariede gebiede effektief te karteer.
39
Barra-Pantoja, Luis Fernando. "A Re-Os Study of Sulfides from the Bagdad Porphyry Cu-Mo Deposit, Northern Arizona, USA". Thesis, The University of Arizona, 2001. http://hdl.handle.net/10150/249252.
Testo completoAbstract (sommario):
Use of Re-Os systematics in sulfides from the Bagdad porphyry Cu-Mo deposit provide information on the timing of mineralization and the source of the ore -forming elements. Analyzed samples of pyrite, chalcopyrite and molybdenite mainly from the quartz monzonite and porphyritic quartz monzonite units are characterized by a moderate to strong potassic alteration (secondary biotite and K- feldspar). Rhenium concentrations in molybdenite are between 330 and 730 ppm. Two molybdenite samples from the quartz monzonite and porphyritic quartz monzonite provide a Re-Os isotope age of 71.7 ± 0.3 Ma. A third sample from a molybdenite vein in Precambrian rocks yields an age of 75.8 ± 0.4 Ma. These molybdenite ages support previous suggestions of two mineralization episodes in the Bagdad deposit. An early event at 76 Ma and a later episode at 72 Ma. Pyrite Os and Re concentrations range between 0.008-0.016 and 3.9-6.8 ppb, respectively. Chalcopyrite contains a wide range of Os (6 to 91 ppt) and Re (1.7 to 69 ppb) concentrations and variable ¹⁸⁷Os/¹⁸⁸Os ratios that range between 0.13 to 22.27. This variability in the chalcopyrite data may be attributed to different copper sources, one of them the Proterozoic volcanic massive sulfides in the district, or to alteration and remobilization of Re and Os. Analyses from two pyrite samples yield an eight point isochron with an age of 77 ± 15 Ma and an initial ¹⁸⁷Os/¹⁸⁸Os ratio of 2.12. This pyrite Re-Os isochron age is in good agreement with the molybdenite ages. We interpret the highly radiogenic initial 1870s/188Os as an indication that the source of Os and, by inference, the ore-forming elements for the Bagdad deposit, was mainly the crust. This conclusion agrees with previous Pb and Nd isotope studies and supports the notion that a significant part of the metals and magmas have a crustal source.
40
Escanilla, Artigas Nicolau. "Recursos minerales de cobre y su explotación prehistórica en el sudeste peninsular. El valle del Guadalentín (Murcia)". Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/399293.
Testo completoAbstract (sommario):
En este trabajo se presenta el estudio de la minería y metalurgia del III milenio cal ANE en el valle del Guadalentín (Murcia). Es el milenio que separa las primeras manifestaciones metalúrgicas de la consolidación de El Argar como estado. El estudio parte de dos ejes diferenciados: Los recursos naturales y los principales poblados con evidencias de reducción de minerales.
Se ha realizado una prospección extensiva de los depósitos minerales de cobre de todo el valle del Guadalentín cubriendo un área de 110 kilómetros en dirección SW-NE y 50 Km en dirección N-S. Durante estas prospecciones se han identificado depósitos de cobre con evidencias de minería prehistórica, Cerro Minado (Huércal-Overa, Almería), Filón Consuelo (Cartagena, Murcia) y Balsicas (Mazarrón, Murcia). El estudio de su registro arqueológico y la comparación con el registro arqueometalúrgico del valle del Guadalentín durante la prehistoria reciente nos permiten proponer una cronología calcolítica para todas ellas.
Paralelamente, también se han prospectado y estudiado los principales asentamientos calcolíticos y del inicio de la Edad del Bronce. Gracias a ello hemos podido obtener un amplio conjunto de materiales vinculados a la reducción de minerales que permiten una aproximación, hasta ahora inédita, a la minería y metalurgia de la prehistoria reciente.
Un primer acercamiento analítico se ha realizado con el estudio químico de 160 minerales, tanto de minas de cobre como de poblados. Se ha utilizado preferentemente la pFRX sobre muestras molidas para tener tanto la composición del mineral de cobre como de la ganga que le acompaña. Gracias a estos análisis hemos podido caracterizar geoquímicamente los recursos del valle del Guadalentín. Con ello, se ha realizado una propuesta de las estrategias de aprovisionamiento de mineral durante el Calcolítico. También nos ha permitido diferenciar aquellas minas con un potencial aprovechamiento prehistórico de aquellas que serían probablemente descartadas.
El estudio arqueometalúrgico de los residuos ha tenido por objetivo caracterizar de qué manera los minerales eran utilizados durante la reducción. Se ha trabajado analíticamente sobre 40 residuos mediante análisis con PIXE, DRX y microscopía óptica y electrónica.
Los resultados obtenidos permiten un definir una situación compleja y altamente transformativa que tuvo como principal referencia la obtención intencional de cobre arsenical. La metalurgia del cobre arsenical, ya desde los primeros siglos de su desarrollo, denota un conocimiento avanzado de las propiedades de los minerales y su distribución en el territorio. La explotación de mineral y la producción de cobre se fue transformando conforme se transformaban las relaciones productivas entre hombres y mujeres durante el III milenio cal ANE. Así, la entrada del fenómeno Campaniforme supondrá una primera transformación importante de las estrategias mineras y metalúrgicas. El punto culminante de todo este proceso fue la implantación de El Argar como entidad política en todo el Sudeste al inicio del II milenio cal ANE. Con él se estatalizó la obtención de cobre, desapareciendo la minería y metalurgia extractiva del valle del Guadalentín.This work introduces a study of mining and metallurgy in the Guadalentín River valley (Murcia) in the 3rd-millennium cal BCE. This is the millennium that separates the first metallurgical manifestations in the region from the establishment of El Argar as a State. The study takes two separate contexts as a starting point: the natural resources and the main settlements with evidence of ore smelting. An extensive survey has been undertaken which focused on the copper ore deposits of the whole of the Guadalentín valley, in an area of 110 km in a SW-NE axis and 50 km in a N-S axis. In the course of these surveys three mines with evidence of prehistoric mining have been identified: Cerro Minado (Huércal-Overa, Almería), Filón Consuelo (Cartagena, Murcia) and Balsicas (Mazarrón, Murcia). The analysis of their archaeological evidence and the respective comparison with the Late Prehistoric archaeometallurgical record of the Guadalentín valley allows us to propose dating all of them to the Copper Age. In parallel, the main settlements of the Copper Age and beginnings of the Bronze Age have also been examined. Thanks to this, we have been able to obtain a wide range of materials tied to the smelting of ores that allow for a hitherto unseen approach to Late Prehistoric mining and metallurgy. A first scientific probing was performed through the chemical study of 160 ores, both from copper mines and settlements. It has been a preference for the use of pFRX and on ground samples in order to learn the composition of both the copper ore and the associated gangue. Thanks to this method we have been able to characterise the resources of the Guadalentín valley geo-chemically. As a result, we have put forward a proposal concerning the Copper Age supply strategies. It has also made possible differentiating the mines with potential prehistoric use from those likely to have been dismissed. The study of the metallurgical debris had the goal of defining how ores were used during smelting. Analytical work was performed on 40 copper smelting and melting debris –slags, slagged ceramics and crucibles - through PIXE, DRX, optical microscopic and SEM analysis. The results have led me to define a complex and highly shifting situation whose main pivot was the intentional production of arsenical copper. From the very first centuries of its development, this arsenical copper metallurgy reveals an advanced knowledge of the properties of the ores and their distribution in the territory. The exploitation of ores and the production of copper shifted progressively along with the productive relations between men and women during the 3rd millennium cal BCE. Thus, the advent of the Bell Beaker phenomenon meant a first major transformation of the mining and metallurgical strategies. The climax of the larger process was the establishing of El Argar as a political entity in the whole of south-eastern Iberia at the beginning of the 2nd millennium BCE. This made the procurement of copper a State prerogative, resulting in the disappearance of mining and extractive metallurgy from the Guadalentín valley.
41
Jacobs, Tamzon Talisa. "Process mineralogical characterisation of the Kansanshi copper ore, NW Zambia". Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/20490.
Testo completoAbstract (sommario):
Kansanshi mine is the largest copper producer in Africa. The deposit is mineralogically and texturally complex due to supergene enrichment resulting in the presence of a variety of primary and secondary copper minerals. This necessitates the processing of ore through three separate circuits: sulphide flotation, mixed flotation and oxide leach, followed by solvent extraction and electro-winning. This study revisits the process mineralogy of the ore using modern mineralogy tools, which for such a large and complex deposit cannot but deliver significant value. Specific focus is given to copper mineralisation and the flotation of the sulphide ores in compliment to another MSc study from the Centre for Minerals Research focusing on mixed ore flotation (Kalichini, 2015). A series of hand samples and grab samples representing the variation in mineralogy and texture of the Kansanshi ore, as well as two run of mine sulphide ore flotation feed samples were used for this investigation. Process mineralogical characterisation entailed optical microscopy, XRF, QXRD, QEMSCAN and EPMA investigations, alongside a series of laboratory scale batch flotation tests of two sulphide ores at two grinds (80% passing 150 μm, 80% passing 212 μm). Copper mineralisation at Kansanshi occurs as both vein-hosted mineralisation, and to a lesser extent sediment-hosted mineralisation. Later breccia-hosted and supergene mineralisation have overprinted all previous mineralisation styles. Chalcopyrite is the main ore mineral for both vein-hosted and sediment-hosted mineralisation styles.
42
Parisot, Jean-Claude. "L'altération latéritique de protores cuprifères au Brésil". Poitiers, 1989. http://www.theses.fr/1989POIT2267.
Testo completoAbstract (sommario):
L'alteration supergene de trois indices de cuivre du bresil, localises entre 5**(o) et 24**(o) de latitude sud est etudiee. On determine les differentes phases d'alteration (smectitique et lateritique) correspondant a une grande mobilite geochimique. La plus grande partie du cuivre est lisciviee et le cuivre restant est associe a la goethite. Une application de cette etude a la prospection geochimique et a la mineralurgie est proposee
43
Thorette, Jacques. "Contribution à l'étude de l'hydrothermalisme océanique : exemple du district minéralisé de York-Harbour (massif ophiolitique de Blow-Me-Down, Bay-of-Islands, Terre-Neuve)". Brest, 1986. http://www.theses.fr/1986BRES2002.
Testo completoAbstract (sommario):
Les mineralisations a cu-fe-zn de york-harbour sont encaissees dans l'unite volcanique situee au sommet de l'ophiolite cambrienne de blow-me-down. Celle-ci s'est formee a l'axe d'une dorsale oceanique a proximite d'une faille transformante. L'organisation en synclinal du secteur mineralise resulte du rejet des failles synvolcaniques en direction nord 135 et nord 45
44
Calvert, M. "Computer modelling of comminution and classification plant". Thesis, University of Leeds, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375346.
Testo completo
45
Kalichini, Monica Shamvuse. "A study of the flotation characteristics of a complex copper ore". Master's thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/16196.
Testo completoAbstract (sommario):
Kansanshi copper mine is situated in the north western province of Zambia. Weathering has given rise to a vertically zoned profile comprising leached, refractory, oxide, mixed and hypogene sulphide mineralisation. As a result of the mineral variations, the processing plant treats three distinct ore types; oxide, sulphide and mixed. The objective of this study was to investigate the floatability of a complex Kansanshi mixed copper ore comprising sulphide and oxide minerals with a view to achieving an optimal flotation performance in the treatment of the Kansanshi ore body. This required an in-depth analysis of the mineralogy of the feed as well as tailings samples after different flotation processes involving a range of reagent types and dosage procedures. The ore samples studied represented a high quality (HQ) ore dominated by sulphide minerals and low quality (LQ) ore dominated by oxide minerals. The quality of an ore at Kansanshi is defined by the acid soluble copper (ASCu) content of the ore, which is used as a proxy for oxide mineral content. An important finding in this study was that sulphide minerals are also prone to digestion during this analysis. Chalcopyrite was the major copper mineral in the HQ ore, constituting 3.9 %, but only 1.0 % of the LQ ore. LQ ore was dominated by chrysocolla, which constituted 3.8 % of the ore. The treatment of HQ ore with 30 g/t SIBX has shown that up to 90 % of the copper can be recovered from HQ ore. On the other hand, while 30 g/t SIBX was sufficient for chalcopyrite recovery in LQ ore, the tailings mineralogy after flotation with SIBX indicated that 78.8 % of the unrecovered copper in LQ ore was present as chrysocolla, 1.3 % as malachite and 5.8 % as chalcopyrite and therefore LQ ore required alternative flotation methods for the recovery of the oxide minerals. Comparison of slug sulphidisation and controlled potential sulphidisation (CPS) of LQ ore have shown that CPS performs better than slug sulphidisation only when the correct potential range and SIBX dosage after sulphdisation are used. Tailings mineralogy of LQ ore after sulphidisation showed a copper deportment of 0.1 % cuprite, 0.6 % malachite, 0.8 % chalcopyrite and 84.8 % chrysocolla, suggesting that all oxide copper minerals present in the LQ ore, except chrysocolla, are amenable to flotation using SIBX after sulphidisation. This observation was further verified through sulphidisation in a microflotation cell, which showed malachite recovery of 18.2 % compared to only 0.5 % of the chrysocolla. A techno-economic analysis comparing slug sulphidisation and CPS has indicated that CPS using a potential range of -300 to -400 mV performs better than slug sulphidisation from an economic stand point. At this potential, a NaHS:SIBX ratio of 7:1 was required, further highlighting the importance of using the correct collector dosage after sulphidisation.
46
Del, Rio Salas Rafael Eduardo. "METALLOGENESIS FOR THE BOLÉO AND CANANEA COPPER MINING DISTRICTS: A CONTRIBUTION TO THE UNDERSTANDING OF COPPER ORE DEPOSITS IN NORTHWESTERN MÉXICO". Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/145742.
Testo completoAbstract (sommario):
Northwestern Mexico is characterized by different metallogenic provinces that are included along the Basin and Range, the Sierra Madre Occidental, and the Baja California geological provinces. With the purpose of contribute to the current understanding of the mineralizing processes, the present study focused on two important copper metallogenic provinces: the Cananea Porphyry District in Sonora, and the Sediment-hosted Stratiform Copper- and Mn-deposits in Baja California Sur. The U-Pb zircon ages from the mineralizing porphyries from Cananea district suggest a continued magmatic activity period of ~6 Ma. Also suggests a period of ~20 Ma for the entire magmatic activity in the district. The Re-Os molybdenite ages demonstrate five well-constrained mineralization events in the district; the main mineralization is constrained over a short period of time (~4 Ma). The new molybdenite age from the Pilar deposit documents the oldest mineralizing pulse, suggesting possibly the initiation of the Laramide mineralization in northern Sonora. A detailed study of Mariquita porphyry Cu and Lucy Cu-Mo deposits in the Cananea district was performed. Four hydrothermal stages were defined in Mariquita, whereas a single hydrothermal pulse characterizes Lucy. Emplacement depths between 1-1.2 km, and temperatures between 430-380ºC characterized the mineralization from Mariquita, whereas deeper emplacement depths and higher mineralization temperatures characterized Lucy. The stable isotope systematic and fluid inclusion data determined that the mineralizing fluids in Mariquita deposit are essentially magmatic during the earlier hydrothermal stages, whereas the last stage is the mixing between magmatic and winter meteoric-waters. The mineralizing fluids from Lucy deposit are magmatic in origin. A comprehensive study was performed in the Cu-Co-Zn-Mn ineralization of the Boléo District, and Mn-oxide mineralization along the eastern coast Baja California Sur. The REE and trace element in the Mn-oxides demonstrated the exhalative nature of the mineralizing hydrothermal fluids, and exclude the hydrogenous nature. The stable isotope systematic in ore and gangue minerals, along with the Cu-isotope data helped to decipher the nature of mineralizing and non-mineralizing fluids. The application of Pb, Sr and Re-Os isotope systems was applied to constrain the nature of the fluids involved during the mineralization processes and that the metal sources.
47
Lai, Yueh (Yves). "Thiosulfate leaching of natural Acanthite ore in copper-ammonia-ammonium sulfate medium". Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/61358.
Testo completoAbstract (sommario):
Silver is commonly present in acanthite in nature. Reagents like cyanide are used to extract silver from acanthite ores. However, cyanide can potentially damage human health and environment. The use of cyanide is tightly regulated, thus forcing the industry to seek for alternatives. Thiosulfate is currently the most promising alternative. The leaching chemistry of silver with thiosulfate is complex and maybe supplemented with additives such as ammonia, copper and even ethylenediaminetetraacetic acid. The efficiency of silver leaching is improved with the use of these additives.
The use of cyanide for silver leaching in Navidad project in Argentina is not permitted, so the use of thiosulfate leaching as an alternative was investigated. The application of thiosulfate leaching to Navidad ores containing acanthite was the focus of this thesis. This thesis provides experimental evidence that supports the use of thiosulfate with additives as a promising alternative to conventional cyanidation method for the Navidad deposits and for similar deposits, wherever found.
Thiosulfate leaching of silver is known for two pathways: silver in acanthite is substituted by cupric or by cuprous ion. The cupric pathway is thermodynamically more favourable, but various factors may affect extraction. Batch leaching tests showed that Navidad ore samples may be leached using thiosulfate, with silver extraction affected by variables including thiosulfate concentration, ammonia concentration, initial copper addition, pH, temperature, EDTA addition and the presence or absence of air sparging. The most significant variables were thiosulfate concentration, ammonia concentration, copper addition and pH. Cyanidation yielded 91.2% extraction of silver from a sample of Loma de la Plata, and thiosulfate leaching with 0.2 M of thiosulfate and 1.0 M of ammonia yielded comparable extractions: 92.1% and 87.0%, respectively. Initial copper addition increases extraction rate from 66.2% to 72.3% after 72 hours, and air sparging increases extraction rate to 84.8% after 72 hours. Other samples from the Navidad Project were also tested and found to be amenable to thiosulfate leaching. LDLPMC and Connector Zone (CZMC) sample were found to have potential for thiosulfate leaching to achieve a high silver extraction.Applied Science, Faculty of
Materials Engineering, Department of
Graduate
48
Tatiya, Ratan Raj. "Ore estimation and selection of underground mining methods for some copper deposits". Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/46738.
Testo completo
49
de, Sousa Eudes Alves 1959. "Impact of geology on ore grade estimation of a porphyry copper deposit". Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/277264.
Testo completoAbstract (sommario):
Accurate ore estimation processes are of crucial importance in the mining scenario. Over the last 20 years, one practical approach to improve ore grade estimation has encouraged the need to incorporate the geology of the ore deposit being estimated in the estimation process. The objective of this study is to investigate the impact of the geology on the kriging estimation of the ore grade of a portion of a porphyry copper deposit. Preliminary data analysis demonstrates the need to perform a subsequent variogram modeling and kriging estimation of the ore grade by rock type separation. Global and local estimations were done to assess the influence of the geology on the ore grade estimation at a global and local scales. The results obtained in this study demonstrated that for the portion of the deposit studied the incorporation of the geology does not produce substantial improvement on the ore grade estimation.
50
Creach, Monique. "Accumulation supergène de cuivre en milieu latéritique : étude pétrologique, cristallochimique et géochimique de l'altération du skarn de Santa Blandina (Itapeva, Bresil)". Poitiers, 1988. http://www.theses.fr/1988POIT2344.
Testo completoAbstract (sommario):
On etudie l'indice cuprifere de santa blandina (bresil) provenant de l'alteration d'un skarn porteur d'une mineralisation sulfuree a chalcopyrite et bornite. Les produits argilomorphes provoquent l'epigenie des mineraux du skarn et des solutions percolantes provoquent l'evolution mineralogique de ces produits. Les analyses mineralogiques et cristallochimiques determinent la nature exacte de ces phases argilomorphes et montrent la difficulte de l'incorporation du cuivre dans un reseau regulier d'argile