Spelling suggestions: "subject:"zinc ore"" "subject:"inc ore""
41 |
Exploration status for oxide and sulphide zinc ores at Skorpion Zinc Mine, NamibiaSitoka, Stefanus January 2015 (has links)
The thesis is inspired by recent interests in oxide zinc ores caused by new developments in the technology of hydrometallurgy. The improved techniques turned the non-sulphide zinc ores in to attractive exploration targets due to a number of advantages such as low metal recovery costs and favorable environmental aspects such as the obvious absence of sulfur (Large, 2001). Historically extraction of zinc metal from oxide ores was not possible until recently. The metallurgical complexity resulted in a lack of interest and hence some economic oxide zinc ores might have been missed by conventional exploration techniques. The study presents a review of exploration status at Skorpion mine based on different exploration techniques and their application to sulphide and oxide zinc ore exploration. The challenge facing the mineral exploration industry today is the inability to detect mineral deposits under cover. Therefore a key to successful exploration program lies in the selection of the right exploration technique. Important parameters that should be highlighted in the exploration methodology are the geological situation of an area, equipment applicability and effectiveness, survey limitation, equipment mobilization and the safety aspects involved. The aim of this thesis is to provide a general guideline for sulphide and non-sulphide zinc ore exploration on the Skorpion area and other similar geological environments. Geochemical surveys appears to be more complimentary in exploration of non-sulphide zinc exploration. Although geochemical techniques are preferred, it is equally important to choose the right soil horizon. Furthermore, sample media may mean the difference between success and failure in geochemical exploration of non-sulphide zinc mineralization, due to high mobility of zinc in the surficial environment. On cost comparison, surface geochemical surveys programs are more cost effective except for litho-geochemical sampling which are commonly carried out through subsurface drilling. Geophysical techniques have limited application in exploration of non-sulphide zinc mineralization due to a lack of major physical properties (e.g., magnetic and electrical properties) in non-sulphides unlike their sulphide counterparts. However geophysical methods are commendable in delineating massive and disseminated sulphides mainly if they are associated with major Fe minerals (pyrrhotite or magnetite). In addition, geophysical techniques may be effective in mapping of subsurface primary and secondary structures such as basin faults which might have acted as pathways for metal-rich fluids. Terms non-sulphide and oxide zinc mineralization are used interchangeably throughout the thesis. Recommendations on regional and local target generation are presented in the thesis to give some basic guide lines on target generation strategies. The most important conclusion reached in this study is that, success in exploration for non-sulphide or sulphide zinc mineralization might be enhanced through the integrated exploration methodology.
|
42 |
Inorganic and organic geochemistry of the zinc ores of the Idol Mine, East TennesseeLu, Jun 16 June 2009 (has links)
The Idol Mine, operated by Clinch Valley Mining Company, is located at the southern end of the Copper Ridge District in Northeastern Tennessee. It is a relatively typical carbonatehosted zinc (Mississippi valley Type) deposit. The ores occur as interfragmental fillings within carbonate breccia bodies of the Lower Ordovician Kingsport and Mascot formations. The paragenesis study reveals that sphalerite, the only zinc mineral, precipitated at the earliest stage of ore formation accompanied by minor amounts of dolomite and marcasite. A major stage of coarse white dolomite precipitation took place after sphalerite. Minor amounts of other gangue minerals including pyrite, calcite, quartz, gypsum and fluorite all postdate ore formation. Field observations complemented by macro- and micro-scale examination of polished sections and doubly-polished thin sections reveal that five alternating light and dark growth bands are distinguishable within sphalerite and are correlatable throughout the mine. Electron microprobe analyses across the growth zones of the sphalerite reveal that the dark A, C, and E bands are characterized by relatively high Cd, Cu and Pb content and the light B and D bands by relatively high Fe content. It is also noted that there are two types of host breccias, one with bleached rims and the other without. Early bleach rimmed breccias are most likely the relics of karst-related breccias and later non-bleached breccias appears to be of tectonic origin. Representative sphalerite, gangue dolomite and host dolostone breccias have been sampled and tested by mass spectrometry to determine the presence and nature of hydrocarbons. The GC/MS analyses reveal that all the samples examined contain aliphatic hydrocarbons with minor amounts of aromatic compounds. The aliphatic hydrocarbons range from C₂₁H₄₄ to C₃₃H₆₈ and are most likely of terrestrial plant origin. On the basis of new observations combined with previous data, a model involving the mixing of two distintive fluids is proposed to account for the formation of the Idol zinc mine. / Master of Science
|
43 |
Geological and stable isotope studies of carbonate-hosted lead zinc deposits in Nanisivik, northern Baffin Island, N.W.T., Canada.Ghazban, Fereydoun. Ford, D.C. Schwarcz, H.P. Unknown Date (has links)
Thesis (Ph.D.)--McMaster University (Canada), 1988. / Source: Dissertation Abstracts International, Volume: 62-13, Section: A, page: 0000.
|
44 |
The geology of the Tsumeb carbonate sequence and associated lead-zinc occurrences on the farm Olifantsfontein, Otavi Mountainland, NamibiaKing, Clive Howard Matthew 05 August 2014 (has links)
M.Sc. (Geology) / Please refer to full text to view abstract
|
45 |
The metallogeny of Cu-Ni and Zn-Cu-Pb deposits of the Frederickson Lake area, central Labrador Trough /Gebert, James, 1962- January 1988 (has links)
No description available.
|
46 |
Geology, geochemistry and genesis of Montauban lead-zinc depositsPrabhu, Mohan Keshav. January 1981 (has links)
Lithogeochemical investigations were carried out in and around the Montauban polymetallic deposits of the Grenville Province, Quebec. A number of chemical criteria used to distinguish sedimentary and igneous protoliths for the ore host rocks were tested and found to be weak in their discriminating capabilities. Critically evaluated chemical criteria show that the protoliths for quartzofeldspathic gneisses, quartz-rich rocks, and host rocks were mainly siliceous sediments and intercalated carbonate lenses. Hornblende gneisses of the Montauban area are orthogneisses. They and other orthoamphibolite rocks in the study area have a tholeitic affinity. Incompatible element chemistry suggests that they were formed in an island-arc (including back-arc) environment. / Alteration associated with the Montauban Pb-Zn deposits is weak and has a narrow lateral extension with erractic chemical halos close to the ore-bearing zones. A CaO-rich zone extends up to 140 m laterally to the east from the calc-silicate ore zone, and an anomalous MgO zone extends on both sides of the cordierite-anthophyllite ore zone into the quartzofeldspathic gneisses. The cordierite-anthophyllite gneiss host rock is more anomalous in Zn, Pb, Cu and Au than the calc-silicate host rock. Erractic high concentrations of Zn and Au occur within the quartzofeldspathic gneisses close to both ore-bearing zones. Copper and Au occur at slightly greater depths than Zn and Pb within the deposits. / The Montauban Pb-Zn deposits were formed in a mainly sedimentary environment, probably by exhalative processes, and were metamorphosed to the almandine-amphibolite facies with the enclosing sediments.
|
47 |
New geochemical constraints on the genesis of the Gamsberg zinc deposit, Namaqualand Metamorphic Province, South AfricaFoulkes, Susan Elizabeth January 2014 (has links)
The base metal massive sulfide deposits of the Aggeneys-Gamsberg (A-G) District are hosted within the Mesoproterozoic Bushmanland Group of the Namaqua-Natal Metamorphic Complex in the Northern Cape Province of South Africa. The district displays an apparent eastward trend in the economic concentration of base metals (+ barite) from relatively Cu-Pb-rich, Ba-poor mineralisation at Black Mountain to Zn- and Ba-rich ores at Gamsberg. Base metal sulfides at Gamsberg are restricted to the so called Gams (Iron) Formation which comprises a sulfidic mineralized unit (“B”) enveloped within a sequence of meta-sedimentary units (“A” and “C”). The aim of the study was to shed further light on the genesis and chemical evolution of the sulfide mineralisation at Gamsberg in the context of the entire A-G District, by interrogating further the apparent district-wide trend in base metal distribution. The Gams Iron Formation was sampled and studied from one key drill core intersection (“G1”) which intersects the largest part of it as described elsewhere; a small number of additional samples from a second drill core (“G2”) complemented the main sample suite. Minerals that make up the silicate assemblages across the studied section include quartz, garnet, pyroxene, pyroxenoid, phyllosilicates, carbonates, amphiboles, oxides (chiefly magnetite) and graphite. In a stratigraphic context, the mineralogical variations conform directly to those documented in the relevant literature from the Gamsberg locality. These are coupled, where possible, with mineral-chemical profiles of selected silicate species which replicate those of bulk-rock compositions, particularly with respect to Mn, Fe and Ca in the upper C Unit of the studied section. These signals collectively track the characteristic transition from a terrigenous, siliciclastic sediment-dominated footwall to an exhalative sediment-dominated hanging wall to the sulfide mineralisation as also seen in similar deposits elsewhere, particularly with respect to the characteristic Mn-rich signature increasingly observed in the hanging wall C Unit. The foregoing suggests that the examined section faithfully records the interpreted primary stratigraphy of the deposits, despite the complex structural and metamorphic overprint that characterises the region. This facilitates a stratigraphic analytical approach on the sulfidic Unit B, through a combination of mineral-chemical and stable isotope analyses. Dominant sulfides in Unit B are sphalerite and pyrite, with lesser pyrrhotite and minor galena. Sphalerite shows high and generally invariant contents of Fe (mean 12.18wt%, as FeS) whereas Zn anti-correlates with Mn (mean 5.58wt%, as MnS). Isotopic analyses for S, Fe and Zn in hand-picked sphalerite and pyrite separates were used with a view to providing new evidence for chemical and isotopic variation within the sulfide ore-body in a vertical (i.e. stratigraphic) sense, discuss the implications thereof, and ultimately interpret the new data in light of similar existing data from the A-G District and elsewhere. The δ³⁴S data for pyrite (plus a single pyrrhotite grain) and sphalerite from both cores G1 and G2 show comparable compositional ranges between 22.9 and 30.4‰ and between 27 and 30.1‰ respectively. The δ⁵⁶Fe data for pyrite show a range between -1.85 and 0.19‰, whereas seven sphalerite separates have a very narrow range of δ⁶⁶Zn from 0.06 to 0.20‰. The atypically high sulfur isotope data reported in this study are interpreted to reflect sedimentary deposition of primary sulfide ore at Gamsberg from an isotopically highly evolved seawater sulfate source through large-scale Rayleigh fractionation processes. Thermogenic sulfate reduction is proposed to have been the main reductive mechanism from seawater sulfate to sulfide, given the absence of very low δ³⁴S data for sulfides anywhere in the A-G District. By contrast, the δ⁶⁶Zn values for sphalerite are for all intents and purposes invariant and very close to 0‰, and therefore suggest little Zn isotope fractionation from an original exhalative fluid source. On this evidence alone, Zn isotopes therefore appear to hold little promise as a proxy of the chemical and isotopic evolution of SEDEX deposits in space and time, although this can only be verified through further application in the broader A-G District and similar deposits elsewhere. The apparent decoupling of Zn and S isotopes in the Gamsberg sulfide deposit, however, points towards diverse sources of these two components, i.e. ascending metalliferous brines versus seawater respectively. Finally, pyrite δ⁵⁶Fe data do show a stratigraphic trend of generally declining values up-section, which are interpreted to reflect the influence of broadly coeval precipitation of isotopically heavy Fe-oxides on a broader-scale – now preserved as abundant magnetite through metamorphism. Further work on the iron isotope composition of silicate-and oxide-hosted Fe on a local-to-district scale will assist in testing this interpretation.
|
48 |
The metallogeny of Cu-Ni and Zn-Cu-Pb deposits of the Frederickson Lake area, central Labrador Trough /Gebert, James, 1962- January 1988 (has links)
No description available.
|
49 |
Geology, geochemistry and genesis of Montauban lead-zinc depositsPrabhu, Mohan Keshav. January 1981 (has links)
No description available.
|
50 |
Petrology and mineral chemistry of sulphide ores and associated metalliferous rocks of the Gamsberg Zn-Pb deposit, South Africa : implications for ore genesis and mineral explorationStalder, Marcel 12 1900 (has links)
Thesis (PhD)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The Gamsberg Zn-Pb deposit is a metamorphosed and multiply deformed sediment-hosted base metal
deposit in the central Namaqua Province of South Africa. The deposit is hosted by the Bushmanland
Group, a late Palaeoproterozoic (2000-1600 Ma) supracrustal succession of quartzite, metapelitic schist
and interbedded metavolcanic rocks. Mineralisation occurs within the central part of the Gams Formation,
a heterogeneous sequence of metamorphosed metalliferous sediments and fine-grained organic-rich
shales. The ore horizon is subdivided into a lower unit of metapelite-hosted ore, an intermediate layer
of phosphorite-hosted ore, and an upper unit of banded garnet-apatite ore. The ore body is enveloped by
unmineralised silicate-, carbonate- and oxide-facies metalliferous rocks, which originally represented
mixtures of Fe-Mn-rich hydrothermal precipitates, authigenic carbonate, and variable concentrations of
detrital material. Based on mineralogical and geochemical characteristics, the metalliferous host rocks are
subdivided into iron formations, coticules, Fe-Mn silicates, impure marbles and barite/Ba-rich quartzite.
Minerals of the Gams Formation mostly represent solid solution between the Fe and Mn end-members
of garnet, pyroxene, pyroxenoid, amphibole, olivine, spinel and ilmenite. Calcium-rich rock types are a
typical feature and characterized by the occurrence of manganoan calcite, clinopyroxene, andradite-rich
garnet and titanite. A successive increase in the (Mn+Ca):Fe value of rocks and minerals is evident with
increasing distance from the ore horizon. Amphibole is restricted to Fe-rich ore-bearing assemblages,
whereas orthopyroxene, clinopyroxene, Fe-rich pyroxenoid and olivine are present in intermediate
assemblages, and Mn-rich rhodonite and pyroxmangite in the most manganiferous assemblages. These
variations are mimicked by an increase in the Mn:Fe value of coexisting garnet and ilmenite group
minerals with increasing distance from ore. LA-ICP-MS analyses have been used to constrain the REE
patterns of garnet and apatite. In the ore-body, these minerals display a positive Eu anomaly, which is
interpreted to reflect a distinct hydrothermal signature. In contrast, garnet and apatite in unmineralised
metalliferous rocks display nil or a negative Eu anomaly.
Primary features of the Gams Formation, such as REE patterns, the banded nature of garnet-apatite ore,
the presence of diagenetic apatite nodules, and the distribution of the redox-sensitive elements Ba and
Mn have been used to constrain palaeo-environmental conditions. The results indicate that metapelitehosted
ore has been deposited in a stratified ocean that was characterised by anoxic bottom waters and
precipitation of Fe and Zn sulphides into organic matter-rich shales. These rocks were superceded by
phosphorite-hosted ore, garnet-apatite ore and metalliferous host rocks that developed in a suboxic to
oxic environment. The large size of the deposit, the internal lamination of the ores and the predominance
of sphalerite and barite are consistent with a vent-distal setting and precipitation of the ore-forming
constituents from dense and reduced hydrothermal fluids, which originated due to reactivation of dormant
growth faults. Collectively, the geological evidence indicates that Gamsberg is bridging the gap betweenthe SEDEX and BHT classifications. The relationships demonstrate that differences between these two
classes of sediment-hosted Zn-Pb deposits are predominantly related to environmental conditions within
localised third order basins and not to fundamental differences in ore-forming processes. / AFRIKAANSE OPSOMMING: Die Gamsberg Zn-Pb afsetting is ‘n meerfasig vervormde en gemetamorfiseerde sedimentgesetelde onedel
metaal afsetting in die sentrale Namakwa Provinsie van Suid Afrika. Die afsetting word geherberg deur
die Boesmanland Groep, ‘n laat Paleoproterosoïse (2000 – 1600 Ma) bokors-opeenvolging van kwartsiet,
metapelitiese skis en tussengelaagde metavulkaniese gesteente. Mineralisasie word gevind in the sentrale
deel van die Gams Formasie. Die Gams Formasie is ‘n heterogene opeenvolging van gemetamorfiseerde
metaalhoudende sediment en fynkorrelrige organiese skalie. Die erts horison word onderverdeel in ‘n
onderste laag van metapeliet-gesetelde erts, n sentrale laag van fosforiet-gesetelde erts, en ‘n boonste
laag van gebande granaat-apatiet erts. Die erts-liggaam word omhuls deur ongemineraliseerde silikaat-,
karbonaat- en oksied-fasies metal-ryke rotse. Hierdie gesteentes word geinterpreteer as oorspronklike
mengsels van Fe-Mn-ryke hidrotermale partikels, outigeniese karbonaat, en verskeie hoeveelhede
detritale materiaal. Gebaseer op mineralogiese en geochemiese kenmerke word hierdie rotse onderverdeel
in ysterformasies, „coticules“, Fe-Mn silikate, onsuiwer marmer en barite/Ba-ryke kwartsiet.
Minerale van die Gams Formasie form meestal soliede oplossingsreekse tussen die Fe en Mn endlede
van granaat, pirokseen, piroksenoid, amfibool, olivien, spinel en ilmeniet. Kalsium-ryke rots tipes is ‘n
tipiese kenmerk van die Gams Formasie en word gekenmerk deur mangaan-ryke kalsiet, klinopirokseen,
andradiet-ryke granaat en sfeen. Daar word ‘n stapsgewyse vergroting van die (Mn+Ca):Fe verhouding
in gesteentes en minerale gevind met toeneemende afstand van die erts horison. Amfibool is beperk
tot Fe-ryke ertsdraende gesteentes, ortopirokseen, klinopirokseen, Fe-ryke piroksenoid en olivien tot
intermediêre gesteentes, en Mn-ryke rodoniet en piroksmangiet tot Mn-ryke gesteentes. Hierdie variasies
gaan gepaard met vergroting van die Mn:Fe verhouding in granaat en ilmeniet-groep minerale met
toeneemende afstand van die erts. LA-ICP-MS analises was gebruik om die skaars-aarde element patrone
van granaat en apatiet te bepaal. In die erts-liggaam wys hierdie minerale ‘n positiewe Eu anomalie, wat
geinterpreteerd word as ‘n hidrotermale kenmerk. In ongemineraliseerde gasheer gesteentes wys granaat
en apatiet geen of ‘n negatiewe Eu anomalie.
Primêre kenmerke van die Gams Formasie, soos skaars-aarde patrone, the gebande voorkoms van
granaat-apatiet erts, die teenwoordigheid van diagenetiese apatiet knolle, en die verspreiding van die
redox-sensitiewe elemente Ba en Mn, was gebruik om afleidings oor die paleo-omgewing te maak.
Die resultate het gewys dat metapeliet-gesetelde erts afgeset was onder anoksiese bodem water deur
presipitasie van Fe en Zn sulfiedes in organiese skalie. Hierdie erts gaan oor in fosforiet-gesetelde erts,
granaat-apatiet erts en metaal-ryke gasheer gesteente wat in ‘n suboksiese tot oksiese omgewing ontstaan
het. Die grootte van die afsetting, die interne gelaagdheid van die erts, asook die teenwoordigheid van
sfaleriet en bariet dui op ‘n distale omgewing relatief tot die hidrotermale bron en presipitasie van die ertsuit digte en gereduseerde hidrotermale vloeistowwe, wat ontstaan het deur die heraktiveering van rustende
groeiverskuiwings. Gesaamentlik bewys die geologiese kenmerke van Gamsberg dat gemetamorfiseerde
SEDEX en Broken Hill-tipe mineralisasie binne die perke van ‘n enkele afsetting kan voorkom. Die
geologiese verhoudings dui aan dat verskille tussen hierdie twee tipes van sedimentgesetelde afsettings
meestal veroorsaak word deur omgewings-toestande binne in gelokaliseerde derde orde komme en nie
deur fundamentele verskille in ertsvormende prosesse nie.
|
Page generated in 0.0596 seconds