Thesis (doctoral)--Universität Lausanne.

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This dissertation examines two issues in the theory of banking: the role and efficiency of a monopoly bank in a spatial economy and, the design of a deposit insurance contract. Chapters 2 and 3 of the thesis present the development and analysis of a simple production economy with two types of agents. Lenders have an endowment of one unit of a good that may be consumed or invested in a firm. Firms have access to a project but lack the capital necessary to operate it and thus are forced to borrow: firms' projects are identically independently distributed crosssectionally. A simple information asymmetry prevents efficient contracting by lenders and firms and results in deadweight default costs being incurred. One way these deadweight costs could be avoided is to establish a "delegated monitor"—a bank—who collects deposits from the lenders and makes loans to firms. This may result in an efficiency gain since the firms' projects are Ltd. so, as the bank makes more loans, the probability that it defaults will be lower than the probability that an individual firm defaults. This diversification reduces the probability that the bank will fail and the probability that default costs are incurred. However, I assume that these costs are related to distance. This restricts the bank's ability to diversify and may induce costly strategic behavior on the part of the bank. The bank may also lend 'locally' in that it may attract deposits in a region yet not make loans to firms near those depositors. The social welfare implications of this bank are examined in Chapter 3. The results show that the socially optimal outcome is one that restricts the firms' ability to compete with the bank in the debt market and that credit rationing may also be efficient. Chapter 4 examines a model where a deposit insurance scheme is designed by a regulator whose objective is to maximize social welfare. There is a single bank in the economy which can be one of two types: the true type is unknown to the regulator. The results show that the regulator's efficacy is improved when regular insurance premia are combined with a premia that are refunded to solvent banks—akin to a deposit insurance fund.

“Exotic-type” Cu silicate-oxide deposits hosted by Miocene pediment gravels represent an unusual, but characteristic, by-product of the supergene enrichment of Cenozoic porphyry Cu deposits in northern Chile. Carbon stable isotopic analysis is employed herein to clarify the environment of exotic ore formation and to provide guidelines for the exploration for non-outcropping mineralisation. Two main sample suites were examined: chrysocolla-rich ores from the Huinquintipa and Mina Sur deposits; and soils overlying a paleochannel in the Huinquintipa area known to be mineralised. The samples were processed using four different analytical techniques to determine their 13C values: (1) Elemental Analysis Isotope Ratio Mass Spectrometry (EA/IRMS) of the whole sample; (2) crushing in vacuo followed by IRMS to analyse fluid inclusions; (3) thermal extraction at 100˚C, followed by IRMS to analyse weakly bound carbon dioxide; and (4) ethylenediaminetetraacetic acid (EDTA) extraction followed by IRMS. EDTA-partial extraction favours the dissolution of minerals with divalent cations, releasing as carbon dioxide the carbon trapped within the crystal structure. All four of these analytical techniques have been used before, but this is the first time that they have all been used together on exotic copper silicate and oxide mineralisation. Three major carbon sources are identified: (1) atmosphere-derived carbon dioxide with a 13C value of around 0 ‰; (2) plant-derived carbon dioxide with a 13C of about -25 ‰; and (3) microbe-derived carbon dioxide with a 13C of approximately -50 ‰. The bulk of the carbon liberated by EA/IRMS was plant-derived. The thermally- and crushing-released carbon dioxide has the highest proportion of atmosphere-derived carbon, whereas EDTA-extraction preferentially liberated the lightest of carbon. On the conclusion that EDTA preferentially dissolved Cu-rich silicate mineraloids, it is concluded that microbial consortia, including methanogenic microbes, were hosted specifically by the high-grade Cu assemblages and plausibly played a critical role in their precipitation. The same microbial-carbon signature was obtained through the EDTA-extraction of soil samples above the paleochannel. Carbon isotopic analysis of CO2 sequestered through EDTA-extraction could therefore be used as an exploration tool for buried exotic mineralisation. Future exploration should exploit the presence of microbes in niche-specific environments. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2007-12-19 15:43:17.198 / Anglo American plc

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The Morrison deposit, located at the Levack mine in the City of Greater Sudbury, is a footwall-type Cu-Ni-platinum-group-element (PGE) deposit hosted within a zone of Sudbury Breccia in the Archean Levack Gneiss Complex beneath the North Range of the Sudbury Igneous Complex. It consists of sharp-walled, sulfide-rich veins that are enriched in Cu-Pt-Pd-Au relative to contact-type mineralization and can be subdivided based on vein geochemistry, mineralogy, texture, and morphology into a pyrrhotite-rich upper domain, a chalcopyrite-rich lower domain, and a pyrrhotite equal to chalcopyrite middle domain. All domains contain steeply to vertically dipping first-order sulfide veins, irregular and discontinuous second-order sulfide veins, and disseminated sulfides in country rocks. First- and second-order veins can be further subdivided into inclusion-free veins typically within Sudbury breccia matrix or along clast-matrix boundaries, and very irregular and inclusion-rich veins associated with leucosomes in mafic gneiss clasts and granophyric-textured dikes. First-order veins consist of pyrrhotite > chalcopyrite = pentlandite > magnetite in the upper domain, pyrrhotite = chalcopyrite > pentlandite > cubanite > magnetite in the middle domain, and chalcopyrite >> pentlandite > pyrrhotite = cubanite > magnetite in the lower domain. Second-order veins consist of pyrrhotite = chalcopyrite > pentlandite > magnetite and chalcopyrite = millerite = pentlandite in the middle domain, and chalcopyrite >> millerite, millerite > chalcopyrite, bornite >> chalcopyrite, and millerite > bornite > chalcopyrite in the lower domain. Second order veins are adjacent to and in contact with epidote, amphibole, chlorite, carbonate, quartz, and magnetite alteration minerals. Sulfide mineralization in the Morrison deposit is similar to other footwall mineralization associated with the SIC. The veins appear to have been emplaced preferentially into zones of Sudbury Breccia that were within ~400m of the basal contact of the SIC, because that lithology is more permeable and because those zones are within the thermal aureole of the cooling SIC permitting penetration of sulfide melts. The mineralogical, textural, and geochemical zoning in the chalcopyrite-pentlandite-pyrrhotite-rich parts of the Morrison deposit are best explained by partial fractional and/or equilibrium crystallization of MSS and ISS. Bornite ± millerite-rich mineralization are interpreted to have formed by reaction of residual sulfide melts with wall rocks, consuming Fe and S to form actinolitemagnetite- epidote-chlorite-sulfide reaction zones and driving the sulfide melt across the thermal divide in that part of the Fe-Cu-Ni-S system to crystallize borniteSS ± milleriteSS. Gold-Pt-Pd appear to have been more mobile than other metals, forming localized zones of enrichment, although it is not clear yet whether they were mobile as Au-Pt-Pd-Bi-Te-Sb-rich melts or aqueous fluids.

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