Dissertations / Theses on the topic 'Lead-zinc ore'

Automatic sensor-based sorting is a clean preconcentration technique that can be used to separate valuable ore rock from waste rock based on the difference of the detected physical properties. This research evaluated the amenabilities of a Mississippi Valley type lead-zinc ore sample from Pend Oreille Mine to X-ray Fluorescence Sorting, X-ray Transmission Sorting, Optical Sorting and Microwave-Infrared Sorting using laboratory-scale bench-top sensing systems. A methodology for laboratory-scale quick evaluation of the amenability of an ore sample to automatic sensor-based sorting using bench-top sensor systems was generated as reference for future study. The preliminary testwork results showed that the two X-ray methods exhibited the best sorting results. About 37.7%~52.8% of the feed mass could be rejected as waste while above 95% of the lead and zinc was recovered in the product. The sorting feed (-37.5+26.5 mm) could be upgraded by a factor of 1.5~2. The optical sorting method seemed not as effective as the X-ray methods. Only 18.8% of the sorting test feed (-37.5+26.5 mm) was rejected to maintain above 95% metal recovery in the product. The test feed was upgraded by a factor of 1.2. Microwave-Infrared sorting results demonstrated that carbonate gangue mineral does not heat when exposed to microwave heating, while lead-zinc bearing sulfide does. Factors such as particle size, heating time and quantity of particles being heated at a time would influence microwave heating of rocks. Sorting feed of -19+13.2 mm presented the best segregation results after 10s of microwave heating. Above 95% of lead and zinc was recovered in a mass yield of 70% to the product. The test feed was upgraded by a factor of 1.4. The preconcentrate of X-ray Fluorescence sorting had a bond work index 12% smaller than that of the feed ore. The overall metal (lead and zinc) recoveries and grades in the flotation products were also improved after XRF sorting. The costs of both the grinding and the flotation reagent could also be reduced due to the reduction of the feed mass by rejecting the dolomitic gangue minerals up to 50%.

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.

Etude dans le cadre de l'extraction de cu des minerais de type chalcopyrite. Lors de l'attaque des minerais de type chalcopyrite par des solutions de cu(ii) en milieu fortement chlorure, les metaux presents dans le minerai sous forme de sulfures passent en solution soit partiellement soit en totalite, et s elementaire precipite. Mise au point du dosage polarographique des ions cu, pb, zn et fe dissous. L'electrolyse de solutions a teneur elevee en cu(i) et contenant pb(ii), zn(ii) ou fe(ii) a mis en evidence un phenomene de codeposition de pb avec cu lorsqu'on opere a des densites de courant elevees, tandis que ni zn ni fe ne se codeposent avec cu

Thesis (Ph. D.)--University of Texas at Austin, 1998.
Vita. One folded ill. in pocket. Includes bibliographical references (leaves 222-235). Available also in a digital version from Dissertation Abstracts.

Mixed sulphide-oxide lead and zinc ores are most often found in the transition, and occasionally in the oxidised, zones of lead-zinc ore bodies. They are of great importance because there are numerous unexploited or abandoned reserves of these ores in the world. However, they present difficulties for conventional mineral processing due to complex mineralogy. In this thesis, the specific problems associated with these types of ores are described and methods for solving these problems, combining economic and technical considerations, are discussed. The results of experiments carried out at laboratory scale are presented, in which the dissolution of a mixed ore sample from the Angouran mine in Iran in sulphuric acid in the absence of oxidants and also the dissolution of the sulphide part of sample in ferric sulphate-sulphuric acid solutions in the absence and presence of other oxidants, i.e. oxygen, potassium permanganate, manganese dioxide and hydrogen peroxide. Fractional factorial experimental designs were used to determine which variables are significant and understand how these variables interact and drive the dissolution processes. Mathematical models are derived from the statistical analyses of the results. The kinetic studies indicate the rate controlling steps in non-oxidative and oxidative leaching are: diffusion of products back to the exterior surface of oxidised zinc minerals, and diffusion of ferric ions through the layer of elemental sulphur surrounding the sphalerite particles to the surface of the unreacted core of sphalerite particles, respectively. The dissolution of significant minerals in the ore sample, i.e. smithsonite, hemimorphite, sphalerite, cerussite, mimetite and kehoite during non-oxidative and oxidative leaching at optimal conditions were investigated by the XRD method. The results show the feasibility of zinc recovery from mixed sulphide-oxide lead and zinc ores, which underlines the potential of this approach. A conceptual flow diagram for the hydrometallurgical processing of these ores is proposed.

L'etude petrogenetique des minerais de chessy-les-mines a permis de preciser la nature de la mineralisation et l'etude des deformations, de retracer l'evolution geologique complexe. Il est apparu que les metamorphismes ont amene une homogeneisation et une purification chimique des mineraux du minerai alors que leur recristallisation lors de la mise en place du granite a entraine un rajeunissement chimique. Cette approche petrogenetique et geochimique renforce la parente genetique entre chessy-les-mines et saint bel

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.

This research covers the fundamental aspects of the direct leaching of sphalerite by considering the dissolution of silver, lead, and copper contents and their effects on the process. The effects of independence variables such as sodium hydroxide, potassium permanganate, hydrogen peroxide, lead nitrate, sodium chloride, dissolved oxygen, temperature, glycine concentration, dissolution time, and particle size on the process were investigated. All the outputs have been modelled and optimised through the analysis of variance.

Une prospection geologique systematique de ces terrains a conduit a la reconnaissance de quatre principaux types de mineralisations dans le socle, le devonien inferieur et le cretace : 1 - une mineralisation stratiforme a zn-pb-ba-f de type sedimentaire - exhalatif omnipresente au sommet de la barre calcaire emsienne (devonien inferieur). 2 - de nombreux filons de types b. P. G. C. A gangue de siderite avec, pour certains, presence importante de barytine ou de fluorine ; ces filons correspondent a une phase de mineralisation tardi-hercynienne, probablement en liaison avec une phase tectonique compressive impliquant un contexte decrochant a composante cisaillante senestre, evoluant progressivement vers une distension nord-sud. 3 - des amas metasomatiques a mg-fe dans la barre calcaire emsienne, pouvant representer le sommet du systeme hydrothermal responsable des filons tardi-hercyniens du socle. 4 - la dissemination de galene dans les calcaires du santonien et de petits amas decimetriques de barytine secants sur la dolomie greseuse du cenomanien ; ces indices traduisent la remobilisation de filons tardi-hercyniens principalement d'apres l'identite des compositions isotopiques du plomb.

This thesis is written in four parts, the first three of which either have been, or are intended to be submitted to joumals for publication and hence have their own individual abstracts. Part A presents the results of work on the Mount Isa lead-zinc orebodies themselves. Part B addresses the formation of the major development of fme-grained pyrite bodies at Mount Isa, incorporating some of the evidence and argument from the HYC deposit at McArthur River. Part C combines investigations of similar aspects of the mineralisation at the HYC deposit, Hilton deposit, and the non-commercial Mount Novit prospect, and attempts to draw comparisons between these systems and Mount Isa. Part D presents geochemical data for Mount Isa and Hilton deposits and discusses some of the constraints on processes of ore formation. The central thesis is that the Mount Isa lead-zinc lodes have not formed by synsedimentary processes, as almost universally believed, but are the result of shear controlled replacement along bedding, following lithification, peak metamorphism, and the bulk of the ductile deformation. Fine-grained stratiform pyrite forms a major part of many sediment-hosted lead-zinc systems, and is universally regarded as forming in early diagenesis as a result of biogenic sulfate reduction. Stratiform pyrite at Mount Isa has characteristics suggesting it did not form early in diagenesis, but was deposited probably by abiogenic sulfate reduction, after development of both a bedding-parallel and a crosscutting cleavage. This proposed late origin of the Mount Isa fme-grained pyrite is consistent with reinterpretation of existing sulphur isotopic data that suggests that the two generations of fine-grained pyrite at HYC are hydrothermal rather than biogenic. Timing relationships for HYC, Hilton and Mount Novit are not as diagnostic as those at Mount Isa. However, Hilton and Mount Novit appear very similar to Mount Isa in terms of timing and ore controls. HYC sulphide relationships are significantly different in that the bulk of the sulphides appear to have replaced bituminous material, rather than metasomatic carbonates and silicates as at the other three deposits. Many features suggest that the HYC sulphides are post-compaction, are younger than ubiquitous microthrust structures, and form at some stage during a post-McArthur Group compressive deformation.

M. Sc.
The Pering Pb-Zn deposit is hosted in the stromatolitic dolomites of the Campbellrand Subgroup of the Ghaap Group, Transvaal Supergroup. The deposit is situated 20 km northeast of the town Reivilo in the semi-arid region of the Northwest Province, South Africa. It has been classified as a Mississippi Valley type deposit and is, together with the Bushy Park Pb-Zn deposit and F-Pb-Zn deposits near Zeerust, the only known MVT deposit of Paleoproterozoic age. The Pering open cast mine has been operational since 1986, yielding 18 Mt at an average ore grade of 3.6 wt.% Zn and 0.6 wt.% Pb. The aim of this study is to devise a metallogenetic model by integrating core logging, petrography, fluid inclusion and stable C-0-S isotope studies. The mineralogy includes sphalerite, galena and minor chalcopyrite as ore minerals, with diagenetic pyrite, hydrothermal dolomite, quartz and calcite as gangue minerals. Sphalerite predominates over galena. Mineralisation occurs as (a) disseminated stratabound replacements sheets restricted mainly to stromatolitic zones of the Steekdorings Member of the Reivilo Formation, and as (b) open space infill in breccia bodies that cross-cut the stratigraphy. Three events of hydrothermal brecciation, resultant of prolonged pulses of fluid infiltration, and mineralisation are recognised. The first brecciation event is marked by the cementation of the dolomite host rock by sparry dolomite, closely associated with finegrained disseminated sphalerite and galena. The second brecciation event is of minor importance, and is marked by the formation of small amounts of the second sphalerite generation, while the third, and final, brecciation event is marked by the formation of euhedral sphalerite, galena, quartz, sparry dolomite, and calcite as open space fill.

Do oszacowania stopnia zagrożenia jakie stanowią metale ciężkie i inne szkodliwe dla środowiska pierwiastki, oprócz całkowitej zawartości danego pierwiastka, niezbędne jest ustalenie form w jakich ten pierwiastek występuje. Celem niniejszej rozprawy doktorskiej było rozpoznanie form w jakich występują Zn, Pb, As i Cd w środowiskach wietrzeniowych rozwiniętych na odpadach z wydobycia i przeróbki rud Zn i Pb w okolicy Olkusza. Badaniom poddane zostały próbki ze stawów osadowych ZGH "Bolesław" czynnych od 1986 r. oraz próbki z profili glebowych rozwiniętych na czterech hałdach po wydobyciu złóż utlenionych (galmanów) od końca XIX w. do roku 1985. Do realizacji założonych celów zastosowano zarówno metody mineralogiczne (mikroskopowe i dyfrakcyjne) jak i metody geochemiczne (np. metodę selektywnej ekstrakcji sekwencyjnej). W odpadach poflotacyjnych Zn i Pb występuje przede wszystkim w formie siarczków a rzadziej (Zn głównie w starszym odpadzie) w formie węglanowej. As dominuje jako domieszka w siarczkach Fe. Cd w młodszych odpadach poflotacyjnych stanowi głównie domieszkę w siarczkach Zn a w starszych częściowo przechodzi w formę węglanową a częściowo występuje jako jony wymienne. Próbki z hałd "galmanowych" zawierają Zn w formie smithsonitu lub hemimorfitu, glinokrzemianów z Zn (z grupy smektytu i kaolinitu) oraz Zn zabsorbowany na tlenkach Fe.Największe ilości Pb napotkano w tlenkach Mn a mniejsze w cerusycie, w tlenkach Fe i dolomicie.Asdominuje w formie jonów zabsorbowanych nagoethycie a Cd jako domieszka w węglanach, krzemianach i glinokrzemianach Zn oraz w formie wymiennej. Porówanie geochemicznych i mineralogicznych metod analizy specjacji pierwiastków pokazało, że jedynie kompleksowe spojrzenie na problem specjacji metali w zanieczyszczonych glebach i w odpadach może dawać wiarygodne wyniki a metoda selektywnej ekstrakcji sekwencyjnej nie może być stosowana bez porównania zbezpośrednimi metodami mineralogicznymi. Wykonane badania pokazują, że największe zagrożenie dla środowiska stanowi Cd, który występując w formie wymiennej jest potencjalnie łatwo dostępny dla organizmów żywych. Cd jest najbardziej mobilny w starych odpadach poflotacyjnych oraz w powierzchniowych poziomach gleb na hałdach "galmanowych". Zn i Pb mogą zostać łatwo uwolnione z minerałów w razie zmiany odczynu środowiska na bardziej kwaśny a As po zmianie warunków na redukcyjne.
To estimate the degree of thret posed by heavy metals and other environmentally harmful elements it is necessary to determine the form in which the element occurs, in addition to the total content of the element. The aim of this thesis was to identify the formsof compounds in which Zn, Pb, As and Cd occur in weathering environments developed on wastes from the mining and processing of Zn and Pb deposits near Olkusz (S Poland). The study involved samples from ZGH "Bolesław" flotation tailings ponds active since 1986 and samples of soil profiles developed on four dumps after mining of oxidized ores from the end of the XIX century until 1985. Two types of methodswere used:mineralogical methods (optical and electron microscopy with in situelemental analysis,X-ray diffraction) and geochemical methods (selective sequential extraction and bulk elemental analysis). In the flotation tailings, Zn and Pb occur mainly in the form of sulphides and rarely in the form of carbonates. As is present usuallyas the admixture in Fesulphides. Cd occur in younger tailings as the impurity in Zn sulfides but in older tailings mostly in carbonate and ion-exchangeable form. Samples from the dumps of oxidized ores contain Zn in the form of smithsonite or hemimorphite, Zn aluminosilicates (smectite and kaolinite groups) and absorbed on Fe-oxide.The largest amounts of Pb is encountered in Mn-oxides and less in cerusite, Fe-oxides and dolomite.As dominates as the ions absorbed on goethite and Cd as an impurity in carbonates, silicates and Zn aluminosilicates, and in the form of exchange ions. Simultaneous application of geochemical and mineralogical methods for analysis of speciation of elements has shown that only a comprehensive approach to the problem of speciation of metals in contaminated soils and waste can yield reliable results and that selective sequential extraction method can not be used without a comparison with direct mineralogical methods. The study has shown that Cd occuring in the form of exchangeable ions, potentially available to living organisms, pose the greatest threat to the environment. Cd is the most mobile in the old tailings and in surface horizons of the soils developed on the oxidized ores dumps. Zn and Pb can be easily released from their forms in the event of a change of pH of the environment to a more acidic and As in case of changing conditions to more reductive.

Thesis (M. Sc.)--University of Alberta, 2009.
Title from PDF file main screen (viewed on July 10, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science, Department of Earth and Atmospheric Sciences, University of Alberta." Includes bibliographical references.

Quantitative analysis with the aid of numerical and computational modelling has been used to address geological problems since the 1940s. The number of applications developed and used to solve geological problems has increased largely because of the advent of desktop microcomputers. However, despite the introduction of mathematical-computational methods, the observational, inductive approach of Hutton and Wegner remains deep in the geological science. Qualitative rather than quantitative geology has won in the past because of the naturalistic inclination of geologists - “rather than sit on their desk typing and modelling natural phenomena, they were more interested in exploring the world with the naked eye, spending their time conceptualising models and integrating the data collected in the field”. With globalisation geologists have broadened their objectives as larger and numerous databases are available. Therefore, rather than collecting their own data, they now have new technologies to retrieve and process large databases. The drawback of this advantage is the lack of data quality verification, which can be a substantial problem. However, a statistical treatment of datasets can be a partial solution to this. The author as a geologist felt the need of demonstrating that a quantitative-computer based description of a multivariate geological system could lead to a significant improvement of the understanding of such a system. A line can be drawn to subdivide computational approaches that use inference networks based on physical laws (e.g. Geodynamic modelling) to bound variables, or empirical laws (e.g. Bayesian Probability Analysis) that are not characterised by the nature of the data (such as measures of spatial association). Alternative methods (e.g. Fuzzy Sets, Dempster-Shafer, Neural Networks) have been suggested to treat multivariate data less empirically. A possible way to improve the quantitative analysis is the simulation of geological parameters (Chapter 4 – 5). The interaction between the geologist and the computer is iterative in this case – multiple simulation leads to a refinement of chosen approximation. Nevertheless, this methodology is often biased and arbitrary. The best approach perhaps remains the validation of computational models comparing them against the experimental results and observations. The objective of this thesis was then to apply quantitative/computational tools to different geological scenarios in the Lawn Hill Region, Mount Isa Inlier. Part of this study focused on one of the largest Pb-Zn mineral resources in Australia, the Century zinc deposit. The objective of the first section of this thesis was to discover possible new mineral resources similar to the Century orebody, and comprehend how the mineral deposit formed. Two case study applications to the Lawn Hill Region at regional and mineral deposit scale (Century deposit) are presented. The first study reflects the need of data integration in a multivariate system to obtain a statistical estimate of the likelihood of finding a mineral deposit. The concepts of Bayesian reasoning were reviewed and a computer program (coded in Visual Basic) was developed to perform Bayesian modelling. The results were then compared against an expert-driven model to obtain a predictive map for the Lawn Hill Region. The analysis suggested that most of the mineral deposits/prospects are located where knowledge driven models favour the occurrence of SEDEX mineralisation. The data driven model suggests that other Pb-Zn deposits more likely are proximal to the Termite Range fault. Integration of KD and DD models suggests prospectivity for SEDEX-style mineralisation north of the Edith cluster a vein style ore. The second study involved the quantitative 3D spatial analysis of the Century deposit. The 3D model of the mineral deposit was also combined with a 2D-3D coupled deformational and fluid flow simulation for the mineral deposit. The integration of these modelling tools allowed a better conceptualisation of the variables controlling the spatial distribution of base metals within the mineral deposit. In this case the research effort was directed toward the use of computational tools to solve the classical problem of understanding how the ore deposit formed. The results obtained support (re) mobilisation and a broad scale metal zoning similar to what is observed at Lady Loretta and HYC. Results also illustrated how basin compartmentalisation can control (re)mobilisation, fluid-flow and therefore how a mineral deposit evolves in time. A comparison between the different scale of zoning observed coupled with numerical 2D- 3D results outlined that more likely Century is an exhalative system that however experienced later epigenetic introduction of base metals. Modelling results have in general outlined that classification of geological patterns can be an effective way of discriminating the genesis of an ore deposit. For instance, the textural evolution of a mineral deposit which is derived from a combination of mechanical and chemical processes (the mechano-chemical coupling modelled by Ortoleva, 1994) may represent non-linear behaviour and lead to patterning of the geological system. In this context, the relationships observed and modelled between the evolution of permeability structure and the spatial distribution of mineral grades represent an example of how understanding the dynamics of complex system provides improved interpretations. The third study, focused on the post-mineralisation Lawn Hill Megabreccia, and explores the variety of patterning of sedimentary textures and deformational features, aimed at differentiating the timing and origin of this brecciation event. The research combined qualitative and quantitative analysis of structural, sedimentary and stable isotopic features at various scales. The results indicate a synsedimentary (Cambrian) origin for the brecciation. However, the study has emphasised that different causative processes (e.g. tectonic, meteorite impacts) may lead to similar patterning. To conclude, quantitative modelling of the presented geological examples suggests that we need to improve accuracy and numerical descriptions of the system to reveal the timing of formation and how a certain geological process occurred. In other words the loss of data induced by generalisation and oversimplification (often required in computational and quantitative modelling) can reduce the reliability of a predicted answer. Self-organisation and chaos theories (Synergetics) may be a new way to approach and describe the observed patterning of geological events and could be used to provide better mathematical models to understand ore genesis, discover a mineral deposit or ascertain the origin of a catastrophic event.