Dissertations / Theses on the topic 'Cassiterite'

Orientador: Washington Barbosa Leite Júnior
Resumo: O plúton Saubinha (1.316 ± 16 Ma.) compõe uma das intrusões graníticas do maciço São Lourenço que em conjunto com outros maciços (Caripunas, Abunã e São Simão) representam as áreas de exposição de rochas graníticas, com ou sem depósitos de estanho associados, pertencentes a Suíte Intrusiva São Lourenço-Caripunas (1.32 – 1.30 Ga.). O núcleo de ocorrência dos depósitos primários de estanho ocorre na forma de um stock granítico alongado NW – SE. Constitui-se por biotita-álcali feldspato granitos, cartografados em duas unidades mapeáveis, 1:10.000, e em contatos, aparentemente, transicionais entre si. A Unidade A (UA) que integra tipos heterogranulares a equigranulares de granulação média e, subordinamente porfiríticos de matriz fina; e a Unidade B (UB), restrita a borda leste do plúton, com tipos equigranulares a porfiríticos de matriz fina. Adiciona-se ainda uma lente delgada e não contínua de granito miarolítico a sudeste do plúton e diques de microgranito e aplito que seccionam preferencialmente as rochas da UB. Geoquimicamente são granitos ferrosos, pós-colisionais, tipo A (subtipo A2), de caráter metaluminoso que permeia entre os campos peralcalino e peraluminoso com alcalinidade álcali-cálcica a cálcio-alcalina. Apresentam características de magmas oriundos de anatexia de protólitos quartzo-feldspáticos, de mais alta temperatura (~827,0ºC), pouco hidratados e que se posicionaram em níveis crustais rasos. A variação dos elementos maiores e traços por SiO2 sugere um trend ev... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Saubinha pluton (1.316 ± 16 Ma.) composes one of granitic intrusions of São Lourenço massif, which together with other massifs (Caripunas, Abunã and São Simão) represent the areas of exposure granitic rocks, with or without associated tin deposits, belonging to the evolution of São Lourenço-Caripunas Intrusive Suite (1.32 – 1.30 Ga.). The core of occurrence of primary tin deposits occurs as an NW – SE elongated granitic stock. It consists of biotite-alkali feldspar granites, mapped in two mappable units, in scale 1:10.000, and in apparently transitional contacts. Unit A (UA) that integrates heterogranular to equigranular medium grain types and subordinately porphyritic of fine matrix; and Unit B (UB), restricted to the eastern edge of the pluton, with equigranular to porphyritic fine grain types. In addition, a thin non-continuous lens of miarolitic granite to the southeast of the pluton and dykes of microgranite and aplite that preferentially crosscut the rocks of UB. Geochemically, they are ferrous granites, post-collisional, A-type (subtype A2), of a metaluminous character that permeates between the peralkaline to peraluminous fields with alkali-calcic to calcic-alkali alkalinity. The granites have characteristics of magmas originated from anatexy of quartz-feldspar protoliths, of higher temperature (~827,0ºC), poorly hydrated and positioned in shallow crustal levels. Variation of major and traces elements by SiO2 suggests an evolutionary trend from porphyritic types (UB) ... (Complete abstract click electronic access below)
Mestre

Submitted by Marly Aparecida da Silva (marliy.silva@yahoo.com) on 2018-07-05T14:47:20Z No. of bitstreams: 1 Prospecção geofísica em ocorrência de estanho associada ao Granito São Sepé (RS).pdf: 3205470 bytes, checksum: b43cd08a47eb517586499b5756d7ac66 (MD5)
Approved for entry into archive by Ana Paula Santulo Custódio de Medeiros null (asantulo@rc.unesp.br) on 2018-07-05T16:47:13Z (GMT) No. of bitstreams: 1 silva_map_me_rcla.pdf: 3205477 bytes, checksum: e39798d0c3b2012293b8f8bad2c6cd4a (MD5)
Made available in DSpace on 2018-07-05T16:47:13Z (GMT). No. of bitstreams: 1 silva_map_me_rcla.pdf: 3205477 bytes, checksum: e39798d0c3b2012293b8f8bad2c6cd4a (MD5) Previous issue date: 2018-06-29
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Este trabalho apresenta e discute os resultados gerados através de levantamentos geofísicos terrestres de Eletrorresistividade e da Polarização Induzida (IP) utilizados na investigação de uma ocorrência de estanho (cassiterita) associada a hidrotermalito do tipo greisen, localizada na borda oeste do Granito São Sepé. A área de estudo está localizada na porção central do Escudo Sul-Riograndense, município de São Sepé (RS). A ocorrência mineral está associada a veios de quartzo inseridos nos quartzos xistos do Complexo Metamórfico Vacacaí. Foram realizadas 6 linhas de caminhamento elétrico dispostas paralelamente na direção N30W. Os dados foram processados para elaboração dos modelos de inversão 2D gerados para os parâmetros de resistividade e cargabilidade. Os modelos de inversão 2D indicaram áreas de alta cargabilidade interpretadas como as prováveis zonas de concentração da cassiterita. Os dados de resistividade não foram suficientes para a definição das zonas mineralizadas, uma vez que a encaixante (quartzo-xistos) e os veios mineralizados apresentam valores de resistividade parecidos. Desse modo, os dados de cargabilidade foram utilizados para gerar os modelos de visualização 3D, os quais permitiram determinar a morfologia e a continuidade da provável zona de ocorrência da cassiterita. Os resultados dos modelos de visualização 3D mostraram que na área investigada ocorrem dois conjuntos de veios de quartzo e que os sulfetos ocorrem disseminados, provavelmente, nos veios com direção N30W.
This work presents and discusses the results generated by terrestrial geophysical surveys of DC resitivity and Induced Polarization (IP) used to investigate an occurrence of tin (cassiterite) associated with greisen type hydrothermalite, located on the western border of São Sepé Granite. The study area is located in the central portion of the Shield Sul-Riograndense, municipality of São Sepé (RS). The mineral occurrence is associated with quartz veins inserted in the schist quartz of the Vacacaí Metamorphic Complex. Six electric path lines were arranged parallel in the N30W direction. The data were processed to elaborate the 2D inversion models generated for the resistivity and chargeability parameters. The 2D inversion models indicated areas of high chargeability interpreted as the probable zones of concentration of cassiterite. The resistivity data were not sufficient for the definition of the mineralized zones, since the nesting agent (quartz-schists) and the mineralized veins presented similar resistivity values. Thus, the chargeability data were used to generate the 3D visualization models, which allowed to determine the morphology and continuity of the probable cassiterite occurrence zone. The results of the 3D visualization models showed that in the investigated area two sets of quartz veins occur and that the sulphides occur probably in the veins with direction N30W.

The techniques of X-ray photoelectron spectroscopy (XPS), secondary ionization mass spectroscopy, chemical abstraction analysis and microelectrophoresis were used to confirm the existence of iron films on cassiterite grains recovered from the tin concentrator of Renison Limited (Australia). All analyses indicated the level of surface iron contamination to be far in excess of that characteristic of the bulk mineral lattice. No evidence was found in XPS analyses to support the contention that this iron represented lattice iron that had accumulated on the surface due to migration through the lattice, as has been suggested to be the case for certain sulphide minerals. Instead, all of the experimental data supported the hypothesis that the surface film was the result of previous adsorption of hydrous ferric oxide sols onto the cassiterite surface in the plant environment but which had undergone fundamental structural changes when the sample was dried. Specifically, the presence of the iron film did not change significantly the electrokinetic properties of cassiterite, as is known to be the case for other insoluble oxide minerals in the presence of freshly precipitated hydrolyzed metal ionic species. To reconcile these observations, it was shown independently that drying, both thermally and under vacuum, caused the charge reversal phenomena related to hydrolyzed metal ion adsorption either to diminish or disappear. In the presence of styryl phosphonic acid, the iron contaminated cassiterite exhibited a microflotation response that corresponded remarkably with the actual flotation observed in the plant from which it was taken. A critical examination of the literature revealed that this behaviour was indicative of that reported for other cassiterites in both batch and plant flotation of ores. Most notably the mineral floated strongly between pH 4.0 and 7.5. However, after acid leaching, the pH of maximum recovery moved to more acidic values around pH 2.0 and the mineral floated much less strongly in the slightly acidic to alkaline range. This latter behaviour correlated with a large body of published data for which it was known that the cassiterite used was either a high purity sample, not exposed to solutions containing dissolved metal ionic species, or had been acid cleaned prior to test work. Conversely, results from fundamental studies, where this was known not to be the case, exhibited remarkable consistency with the data obtained for the untreated cassiterite sample. The principal influence of the iron species adsorbed onto the surface of cassiterite was shown to be flotation activation in the pH range where the adsorbed species were not extensively solubilized. In the acidic range below pH 4.0, solubilization of the surface iron entities occurred which caused a severe flotation depressant effect. This solubilization was promoted in the presence of sodium fluoride, a known complexing agent for iron in acidic solutions, and the phosphonic acid. In the latter case, evidence was found for the formation of a soluble iron phosphonate complex. Independent confirmation was also sought and obtained from light scattering photometry to verify the strong affinity of phosphonic acids for hydrous ferric oxide species. Other ionic entities, such as those of magnesium and calcium were found to interact far less strongly. On the basis of this research, it has proven possible to provide a rational interpretation of all previously existing data pertaining to cassiterite flotation with phosphonic acids, for which reasonable sample description and preparation information exist. Such a reconciliation has not previously been provided, either through studies on the effects of cassiterite mineral lattice impurities or other work with dissolved metal ionic species. Furthermore, a significant link has been established between the results of fundamental analyses and industrial related observations. In particular, commercially successful practices, such as fluoride pretreatment of ore slurries prior to cassiterite flotation, now can be interpreted successfully in terms of fundamental ion solution chemistry. The evidence is that such processes involve the solubilization under acidic conditions of adsorbed iron hydroxy sols from the surface of minerals prior to cassiterite flotation. A bulk rejection of the complexed metal ionic species is then made in the water split of the desliming circuit that precedes flotation. The solution chemical evidence obtained supporting such a mechanism is considerable and no finding, in this work or elsewhere, refutes it.
Applied Science, Faculty of
Mining Engineering, Keevil Institute of
Graduate

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
Neste trabalho foi realizado o estudou da eletroflotação de finos de cassiterita e quartzo, utilizando o microrganismo Rhodococcus opacus como biorreagente. Os ensaios de eletroflotação foram realizados em tubo de Hallimond modificado, usando aço inox como cátodo e uma tela de Ti/RuO2 como ânodo. As características da superfície do microrganismo e os possíveis mecanismos de interação envolvidos na bioadesão foram avaliados com base em medições de potencial zeta, análises por espectrometria no infravermelho e análises de micrografias obtidas no microscópio eletrônico de varredura (MEV). Após a interação foi observado um caráter hidrofóbico nas partículas de ambos os minerais, e verificado pelas medidas de ângulo de contato. Através de ensaios de adesão foi observada uma maior afinidade do microrganismo pela cassiterita. Estes ensaios também indicaram o pH da solução como o parâmetro de maior influencia, sendo que, maiores quantidades de bactéria aderida foram obtida em valores de pH em torno de 3,0; com 5 min de interação. O tamanho médio da bolha Sauter, obtido pelo método de difração laser, foi de 26 micrometros, usando 50 mg/L de microrganismo e 51,4 mA/cm2 de densidade de corrente. A densidade de corrente e concentração de bactérias mostraram-se os parâmetros de maior influencia no tamanho das bolhas. Assim, bolhas de tamanho menor foram obtidas quando os valores destes parâmetros foram incrementados. A melhor flotabilidade para a cassiterita foi observada em pH 5,0, sendo 64.5 por cento com uma concentração de bactérias de 50 mg/L. Para o quartzo a porcentagem foi em torno de 30 por cento em toda a faixa de pH e concentração da bactéria. Os ensaios de microflotação mostraram que R. opacus contribuiu para uma elevada flotação da cassiterita e uma limitada flotação do quartzo. Ensaios de flotabilidade para uma mistura sintética de cassiterita-quartzo (1:1) foram também realizados, sendo obtidas recuperações médias de cassiterita de 67,8 por cento com um teor no concentrado de 64,4 por cento, partindo de um teor de alimentação igual a 42,9 por cento de SnO2.
In this work, the electroflotation of quartz and cassiterite fine was carried out using Rhodococcus opacus as bioreagent. The electroflotation cell was Hallimond tube modified, with stainless steel as cathode and Ti/RuO2 mesh as anode. The characteristics of the microorganism surface and the corresponding interaction mechanisms in the bioadhesion were evaluated based on the zeta potential, infrared spectroscopy, scanning electron microscopy and contact angle measurements. After the interaction the resulting particles exhibited hydrophobic character, as verified by the increase of the contact angle. The results, also, showed that the microorganism has a higher affinity for cassiterite particles. It was observed a strong influence of pH on adhesion. The higher adhesion values were obtained around pH 3 and the time required to reach equilibrium was 5 min for both minerals. Current density and bacterial concentration seem to be the main parameters affecting the mean diameter of bubbles. Fine bubbles were obtained when the values of these parameters increased. The mean bubble size obtained (Sauter) by the laser diffraction method was 26 micrometers with an organism concentration of 50 mg/L and current density of 51.4 mA/cm2. The best flotability of cassiterite (64.5 per cent) was observed at pH 5.0 with a R. opacus concentration of 50 mg/L. For quartz the maximum flotability achieved was 30 per cent throughout the all pH range and bacteria concentration tested. It is shown through microflotation tests that R. opacus is able to float cassiterite very well and quartz limitedly. Also, the flotability of cassiterite was evaluated in tests by using a synthetic mineral mixture. An average recovery of 67.8 per cent of cassiterite was obtained with a concentrated grade of 64.4 per cent, starting from 42,9 per cent in the feed grade (SnO2).

Prior to complete crystallization of leucogranitic magma at East Kemptville, tectonic fracturing induced a pressure drop, allowing a NaCl-HCl-HF-rich fluid phase to separate. This fluid caused pervasive sericitization and extracted the ore metals from the melt. It was then channeled into the fractures and caused greisenization in the apical part of the intrusion. During greisenization, the leucogranite was converted into quartz-sericite greisen through sequential replacement of K-feldspar and albite. Muscovite was replaced by topaz to form quartz-topaz greisen, host to sulphide and cassiterite mineralization. In this greisen, the OH$ sp-$ of muscovite is replaced by H$ sb2$O and O$ sp{2-},$ which leads to its dehydration during microprobe analyses. Close to veins, suphides and cassiterite were re-dissolved in quartz greisen. The altering fluid had a pH of 3.0 and contained 4.8m Cl, 3.7m Na, 0.53m Fe and minor F, K, S and Sn as determined from fluid inclusions and mineral equilibria. The temperature of greisenization was determined to be $480 pm 15 sp circ rm C$ using a F-OH exchange geothermometer between topaz and muscovite and oxygen isotopic data on cassiterite and quartz; the pressure was estimated to be 4.1 $ pm$ 1.0 kbars using fluid inclusion isochores. Alteration occurred though a process of compensated infiltration in which small aliquots of fluid were exchanged between the rock and the vein, while the bulk flow was parallel to the vein. This created a distribution of the components controlled by chemical potential gradients; Fe, Sn, S and F were transported away from the vein and Na towards it. Changes in physicochemical parameters of the fluid were quantified using computer simulation, which, in conjunction with fluid inclusion data, indicates that cassiterite precipitated in response to a pH increase. Changes in a$ sb{ rm Cl-}$ and $f rm O sb2$ were insufficient to account for cassiterite precipitation or acted against it. Modeling further showed that

Un sondage de 900 m de profondeur a travers le granite de beauvoir fait l'objet d'etudes mineralogiques sur la distribution de sn, nb, ta, be, zr dans les trois facies. D'une facon generale les variations chimiques des mineraux etudies sont liees d'une part a la composition globale du magma et d'autre part aux conditions physico-chimiques de cristallisation du magma. L'evolution des mineraux a metaux rares milite en faveur du cogenetisme des trois facies

Made available in DSpace on 2014-10-09T12:26:26Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T14:04:05Z (GMT). No. of bitstreams: 0
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2015-05-14T13:21:45Z (GMT). No. of bitstreams: 1 parte1.pdf: 2235233 bytes, checksum: 90091ce5e150c5df82bb72929b3cb2f0 (MD5) Previous issue date: 2008-08-01
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
SnO2 pigments, when doped with chromium, lead to violet or purple colors, depending on chromium oxidation state. There is a need to control the chromophore oxidation state, as Cr(VI) is toxic and carcinogenic, while Cr(III) leads to no risk to living beings. Cr(VI) formation may be avoided with the addition of counterions, that lead to a charge imbalance. In this work, SnO2:Cr pigments were synthesized by the polymeric precursor method, with the addition of molybdenum as counterion. The powder precursor decomposition was evaluated by thermogravimetry (TG) and differential thermal analysis (DTA). The influence of the counterion in the crystalline structure was evaluated by Xray diffraction. The materials were also characterized by infrared spectroscopy, colorimetry and UV-vis spectroscopy. All pigments are crystalline and single phase with cassiterite structure. Chromium formation with hexavalent state was observed in all samples, while Sn0.90Cr0.06Mo0.04O2 presented the lowest amount of this cation, comparing to the other pigments, being the less toxic one. Violet and rose colors were obtained for materials doped with chromium and chromium/molybdenum, respectively, being related to the formation of Cr(IV) in the material structure.
O SnO2 quando dopado com cromo forma pigmentos de coloração violeta e rósea, dependendo dos diferentes estados de oxidação do cromo. Contudo, há necessidade de um controle sobre o estado de oxidação do metal, já que o Cr(VI) é tóxico e cancerígeno, enquanto que o Cr(III) não oferece perigo aos seres vivos. Uma forma de evitar a formação de Cr(VI) é pela adição de contraíons, que levam a um balanço de cargas. Neste trabalho, pigmentos cerâmicos de SnO2:Cr na presença de contra-íon molibdênio foram sintetizados pelo método dos precursores poliméricos. A decomposição dos pós precursores foi estudada por termogravimetria (TG) e análise térmica diferencial (DTA). Foi realizado também o estudo da influência dos contra-íons na evolução da fase cristalina por meio de Difração de Raios-X (DRX). Os materiais foram caracterizados por infravermelho, colorimetria e espectroscopia de UV-vis. Os pigmentos mostraram-se cristalinos e monofásicos com a obtenção da fase cassiterita para todos os sistemas. A formação do cromo no seu estado hexavalente foi observada para todos os sistemas, contudo o pigmento Sn0,90Cr0,06Mo0,04O2 apresentou a menor quantidade formada desse cátion, quando comparado com os demais, tornando-se o menos tóxico dos pigmentos estudados. As cores violeta e rósea foram obtidas para os materiais dopado com cromo e cromo/molibdênio, respectivamente, que está associado à formação de Cr(IV) na estrutura do material.

O Granito Desemborque, um corpo de forma, aproximadamente, circular, situado no sul do Estado de São Paulo, tem área aflorante de 50 km2 e é representado por um biotita sienogranito. O caráter peraluminoso com teores significativos de K2O e Na2O, juntamente com o baixo conteúdo de CaO, altas razões Fe/Mg, elevados valores de SiO2 e de elementos traços como Zr, Nb e Y, atestam a afinidade alcalina do granito que pode ser classificado como do tipo A. Os teores de Y refletem a presença de fases acessórias como parisita de Ce, itrofluorita e monazita. Columbita, zircão rico em háfnio e cassiterita presentes na associação de minerais acessórios do Granito Desemborque foram analisados semiquantitativamente (teores em peso) por MEV-EDS. Com isso foi possível discriminar duas fases evolutivas para a geração de alguns dos minerais de metais raros associados ao corpo; uma francamente magmática (com subfases granítica e pegmatítica) e uma fase hidrotermal. A columbita (teor médio de Nb2O5 de 66,2% e 6,5% de Ta2O5) é nitidamente gerada na fase magmática sendo que na subfase granítica ela tem presença ubíqua e caráter disseminado. O zircão, por sua vez, ocorre nas duas subfases magmática, sendo que na subfase granítica ele teria um caráter mais tardio. O teor médio das análises foi de 9,3% de HfO2, classificando-o como um zircão rico em háfnio. Na fase hidrotermal, é que se desenrolariam os processos de enriquecimento em Hf desse mineral. A cassiterita, os minerais de REE e boa parte dos minerais radioativos têm a sua formação restrita a fase hidrotermal. Dentre as classificações propostas para granitos mineralizados, o Granito Desemborque se aproxima do tipo peralcalino mineralizado a metais raros com tendência a formar depósitos ou ocorrências de Nb e ETR. Os senões seriam o fato desse corpo não ser peralcalino (ele é peraluminosso) e dos potenciais minerais de Y e ETR só terem sido registrados como inclusões minerais hospedadas nos grãos de cassiterita (ítriocolumbita) e de zircão (xenotímio). A falta de concentrações minerais econômicas de Nb-Hf-Sn associadas ao Granito Desemborque pode ser imputada ao caráter anídrico do magma (tipo-A) e a falta ou limitação do fraturamento hidráulico. A ausência de concentrações minerais econômicas em virtude da remoção erosiva da zona de cúpula não se encontra de acordo com os resultados prospectivos encontrados, pois, a presença da cromita nas amostras de leito ativo coletadas nas drenagens estabelecidas bem no cerne do corpo granítico indica a preservação de restos de pendentes de teto da rocha encaixante (ortognaisses com boudins de rochas ultrabásicas).
The Desemborque Granite, a body almost of circular shape, placed in the southernmost part of São Paulo State, has an area of ca. 50 km2. and it is represented by a sienogranite biotite. Its peraluminous features with significant contents of K2O and Na2O, together with low CaO contents, high Fe/Mg ratios, elevated values of SiO2 and trace elements as Zr, Nb and Y, assure the granite alcaline affinity that can be classified as type A. The Y numbers reflect the presence of acessory phases as parasite de Ce, yttrofluorite and monazite. Columbite, zircon rich in hafnium and cassiterite presented in the association of accessory minerals of the Granite Desemborque were semiquantitatively analysed(values in weight) by MEV-EDS. Because of this it was possible to detail the two evolutional phases for the generation of some minerals of rare metals associated to the body; one fairly magmatic (with granitic sub-phases and pegmatitic) and an hidrotermal phase. Columbite (Nb2O5 mean value 66,2% and 6,5% Ta2O5) is clearly generated in magmatic phase and in the granitric sub-phase it has ubiquitous presence and disseminated character. Zircon, in its turn, occurs in the two magmatic sub-phases, and in the granitic sub-phase it would have a later character. The mean value of the analysis was of 9,3% for HfO2, classifying it as a zircon rich in hafnium. In the hidrotermal phase, the enrichment proccesses are developed in Hf of this mineral. Cassiterite, the REE minerals and a large number of radiactive mineral have their formation restricted to the hidrotermal phase. Amongst the proposed classification for the mineralized granites, the Granite Desemborque has an peralkalkine mineralized approach to rare metals with a wide tendency to create deposits or Nb and REE occurences. The opposition could be the fact that this body is not peralkaline (it is peraluminous) and the Y and REE mineral potentials only have been recorded in the hosted mineral inclusions in the cassiterite grains (yttrocolumbite) and of zircon (xenotímio). The lack of profitable Nb-Hf-Sn mineral concentrations associated to the Granite Desemborque can be magma anhydrous character (type-A) and the lack or limitation of the hydraulic fracturing. The absence of profitable mineral concentrations because of the erosive removal of the apical zone is not in agreement with the prospective results found, once the presence of chromite in the samples of the active stream bed collected at the draining which is established exactly in the basis of the granite body indicates the preservation of remaints roof pendant the wall rocks (ortognaisses with boudins of ultrabasic rocks).

L'oxyde d'etain, convenablement dope, possede d'interessantes proprietes de semi-conducteur. L'emploi de la technique sol-gel permet de preparer facilement, a partir de solutions aqueuses, des nanoparticules monodisperses d'oxyde stannique a structure cassiterite. Nous avons plus particulierement emprunte la voie de precipitation d'une solution homogene a partir de la decomposition d'un complexe metallique stabilise par un chelate organique (acide tartrique, acide malique, ou acide thiomalique). Nous avons employe le titane et l'antimoine comme dopant. Le but de cette these a ete d'etudier les relations existant entre les conditions de formation des particules, leurs caracteristiques et la conductivite du solide. L'analyse des spectres infrarouge a mis en evidence, dans les poudres sechees a 20c, la liaison entre les ligands acide-alcool et l'oxyhydroxyde d'etain. Il a aussi ete detecte une bande caracterisant une liaison entre un atome d'etain et un atome de titane par l'intermediaire d'un oxygene. La diffraction des rayons x a montre que deja a 20c, le solide possede un ordre a courte distance ; il cristallise dans le reseau de la cassiterite. La structure n'est pas modifiee par les dopants qui sont inseres statistiquement dans le reseau de la cassiterite. Nous avons observe en microscopie electronique des particules spheriques monodisperses de 2. 5 nm de diametre, d'autant mieux dispersees qu'elles sont chelatees et dopees. Nous avons montre que le ligand limite l'extension de la condensation des chaines de polymere stannique ainsi que les interactions entre particules elementaires. Les resultats des mesures de conductivite ont revele un comportement semi-metallique des poudres dopees au titane, avec une excellente conductivite a 200c

Étude de cinq couplages d'éléments en trace liant FE**(3+) (ion paramagnétique) à un autre défaut chimique dans les cassitérites. Les résultats obtenus par RPE sur monocristal permettent de localiser FE**(3+) en substitution de SN**(3+) en site octaedrique dans les cinq cas. Le traitement thermique de cassitérites naturelles provoque la diffusion sélective du FE**(3+) en fonction de son couplage et la formation de nouvelles microphases ferriques

La zone d'Echassières (Massif Central) concentre un grand nombre de minéralisations magmatiques (Sn, Li, Ta, Nb) et hydrothermales (W, Sn, Sb) en quantité économique ou sub-économique. Les nouvelles données minéralogiques et inclusions fluides des différentes paragenèses hydrothermales de la zone, les signatures chimiques en éléments traces de plusieurs minéraux stratégiques (principalement le quartz, mais aussi les micas et la topaze), traitées par un large panel d'analyses multivariées, et les nouvelles datations U-Pb sur rutile, zircon et monazite, ont permis de mettre en évidence trois évènements hydrothermaux minéralisateurs majeurs à trois époques de l'histoire varisque (anté-Tournaisien, Viséen et Westphalien). Ces minéralisations seraient reliées à trois évènements magmatiques distincts, présentant des signatures en métaux spécifiques, mais induisant tous trois la cristallisation de wolframite
The Echassières area in the French Massif Central hosts a large number of economic to sub-economic magmatic (Sn, Li, Ta, Nb) and hydrothermal (W, Sn, Sb) mineralizations. This thesis produced new mineralogical and fluid inclusion data from various of the W-Sn mineralized hydrothermal systems, studied the trace chemical signature of several strategic gangue minerals (mostly quartz, but also micas and topaz) and processed the data using a spectrum of multivariate statistical approaches, obtained new U-Pb dating on rutile, zircon and monazite. Integration of all results made it possible to recognize the occurrence of three major mineralizing hydrothermal events in this region, which took place during three distinct periods of the variscan orogenic cycle (pre-Tournaisian, Visean and Westphalian). These mineralizations could be related to the intrusion of three distinct magmatic bodies, each with a specific paragenesis, yet, all leading to wolframite and cassiterite crystallization

La province stannifère de Goiás, dans la partie centrale du Brésil, comporte quatre zones (distinctions d'origine structurale, essentiellement), dénommées sous-provinces Tocantins, Paraná, Pirenopolis-Goianesia et Ipameri, et regroupent une vingtaine de massifs granitiques et plusieurs champs filoniens de pegmatites qui sont supposés les responsables d'importantes minéralisations stannifères (avec Nb, Ta, W, F et Be). Chacun de ces massifs a une identité géochimique bien spécifique et c'est donc davantage la convergence métallique (l'étain) plutôt qu'une réelle unité génétique qui caractérise la province stannifère de Goiás et ses massifs granitiques. Le massif granitique de Serra Branca est constitué d'un ensemble de faciès diversifiés, allant d'un granite à biotite, granite à deux micas, jusqu'à un granite à muscovite ; le faciès le plus évolué est représenté par un granite à topaze accessoire, rencontré dans la partie E du massif. L’intense différentiation du massif se fait de façon asymétrique en raison des processus d'altération tardi/post-magmatiques qui ont abouti à la formation d'une intense greisenisation de coupole qui atteint son sommet dans la partie orientale du massif, avec la formation de greisens massifs. L’importance relative des altérations tardi/post-magmatiques développées dans les différents faciès du massif, et d'ailleurs déjà bien présentes dans le granite è biotite, peut se traduire de façon chronologique par une albitisation, une greisenisation S. L. Et puis par une microclinisation. Les principaux minéraux d'intérêt économique liés à l'épisode de greisenisation: sont cassitérite, topaze et béryl. Les phases micacées des différents faciès granitiques et des greisens ont été également perturbées par l'action des phénomènes d'altération tardive. Les biotites, hétérogènes à l'intérieur d'un type granitique donné, sont néanmoins homogènes au niveau du cristal (pas de zonage cur-bordure) ; Al est en position octaédrique et sont donc alumineuses. Les micas blancs présentent un caractère phengitique marqué ; ils sont ferrifères, faiblement magnésiens et titanifères, moyennement fluorés et non lithinifères. Les alterations tardi/post-magmatiques subies par les termes granitiques du massif de Serra Branca ont modifié leur signature purement magmatique originelle. Les variations chimiques enregistrées sont davantage l'expression de ces modifications surimposées

Made available in DSpace on 2014-10-09T12:41:57Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T14:04:43Z (GMT). No. of bitstreams: 0
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-06-11T19:26:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-06-15Bitstream added on 2014-06-13T18:54:23Z : No. of bitstreams: 1 dias_cat_me_rcla.pdf: 1344683 bytes, checksum: 1acaaa814f2b0f234d70b3f93d51ba24 (MD5)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
A mina Bom Futuro é atualmente uma das maiores produtora de estanho do país, com uma produção média anual nos últimos 10 anos de cerca de 2400 toneladas de estanho. As atividades industriais de extração de cassiterita na mina se concentram no morro Bom Futuro e adjacências, em depósitos primários e secundários, respectivamente. No morro Bom Futuro são reconhecidos dois pipes brechados alojados em gnaisses e anfibolitos, que são cortados por diques radiais e anelares de pórfiros graníticos com topázio, os quais são incluídos na Suíte Intrusiva Granitos Últimos de Rondônia (998 a 974 Ma). Pelo menos duas fases distintas de mineralização primária de estanho são identificadas com idades 40Ar/39Ar em zinnwaldita de 994±3 Ma e 993±3 Ma e são representadas por lentes, veios e vênulas de pegmatito e de quartzo. O pegmatito estudado ocorre na porção nordeste do morro, onde aparece hospedado em brechas de pipe e dique de topázio riólito pórfiro e cortado por dique de topázio granito pórfiro. Trata-se de um dique com mais de 200 m de comprimento, espessura variando 3 a 12 metros e de atitude geral N20E/45°SE. Na seção estudada com detalhe, o pegmatito mostra um zoneamento interno bem distinto, dado por camadas ou leitos subconcordantes entre si e com as paredes do dique. Pelo menos três zonas foram reconhecidas com base na mineralogia dominante, são elas do muro ao teto: zona do quartzo e topázio, zona do feldspato potássico e mica, e zona granítica (quartzo e feldspato potássico). Uma provável quarta zona não foi observada, mas segundo os garimpeiros, um leito de até 10 cm de espessura de cassiterita maciça ocorre de modo descontínuo junto ao muro do corpo. A estrutura das zonas é maciça e a granulação varia de média a grossa na zona granítica para grossa a muito grossa ou gigante (?) nas outras...
The mine Bom Futuro is currently one of the largest tin producer in the country with an average annual production over the past 10 years around 2400 tonnes of tin. The extraction industrial activities of cassiterite concentrate on the hill Bom Futuro and surrounding areas in primary and secondary deposits, respectively. On the hill Bom Futuro two breccia pipes are recognized hosted in gneisses and amphibolites, which are cut by radial and ring dikes of granite porphyry with topaz, which are included in the Intrusive Suite Latest Granites of Rondônia (998-974 Ma). At least two distinct phases of primary tin mineralization are identified with zinnwaldita 40Ar/39Ar ages of 994 ± 3 Ma and 993 ± 3 Ma and is represented by lenses, veins and venules of quartz and pegmatite. The studied pegmatite occurs in the northeastern portion of the hill, where it appears hosted in breccias pipe and topaz rhyolite porphyry dike cut by topaz granite porphyry dike. It is a dike over 200 meters in length, thickness ranging 3-12 meters and general attitude N20E/45 ° SE. In the studied section in detail, the pegmatite shows a very distinct internal zoning, given by layers or beds sub concordant among themselves and with the walls of the dike. At least three zones were recognized based on the dominant mineralogy, they are from the wall to the ceiling: zone of quartz and topaz, zone of mica and feldspar, and granitic zone (quartz and feldspar).A possible fourth zone was not observed, but according to the miners, a bed with 10 cm thick of massive cassiterite occurs discontinuously along the wall of the body. The structure of the zones are massive and the granulation varies from medium to coarse in the granite zone and coarse to very coarse or giant (?) In the other two. The primary mineralogy is relatively simple: the quartz is gray to milky white, the... (Complete abstract click electronic access below)

Orientador: Washington Barbosa Leite Jr
Banca: Sebastião Gomes de Carvalho
Banca: César D'Abronzo Martinelli
Resumo: A mina Bom Futuro é atualmente uma das maiores produtora de estanho do país, com uma produção média anual nos últimos 10 anos de cerca de 2400 toneladas de estanho. As atividades industriais de extração de cassiterita na mina se concentram no morro Bom Futuro e adjacências, em depósitos primários e secundários, respectivamente. No morro Bom Futuro são reconhecidos dois pipes brechados alojados em gnaisses e anfibolitos, que são cortados por diques radiais e anelares de pórfiros graníticos com topázio, os quais são incluídos na Suíte Intrusiva Granitos Últimos de Rondônia (998 a 974 Ma). Pelo menos duas fases distintas de mineralização primária de estanho são identificadas com idades 40Ar/39Ar em zinnwaldita de 994±3 Ma e 993±3 Ma e são representadas por lentes, veios e vênulas de pegmatito e de quartzo. O pegmatito estudado ocorre na porção nordeste do morro, onde aparece hospedado em brechas de pipe e dique de topázio riólito pórfiro e cortado por dique de topázio granito pórfiro. Trata-se de um dique com mais de 200 m de comprimento, espessura variando 3 a 12 metros e de atitude geral N20E/45°SE. Na seção estudada com detalhe, o pegmatito mostra um zoneamento interno bem distinto, dado por camadas ou leitos subconcordantes entre si e com as paredes do dique. Pelo menos três zonas foram reconhecidas com base na mineralogia dominante, são elas do muro ao teto: zona do quartzo e topázio, zona do feldspato potássico e mica, e zona granítica (quartzo e feldspato potássico). Uma provável quarta zona não foi observada, mas segundo os garimpeiros, um leito de até 10 cm de espessura de cassiterita maciça ocorre de modo descontínuo junto ao muro do corpo. A estrutura das zonas é maciça e a granulação varia de média a grossa na zona granítica para grossa a muito grossa ou gigante (?) nas outras... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The mine Bom Futuro is currently one of the largest tin producer in the country with an average annual production over the past 10 years around 2400 tonnes of tin. The extraction industrial activities of cassiterite concentrate on the hill Bom Futuro and surrounding areas in primary and secondary deposits, respectively. On the hill Bom Futuro two breccia pipes are recognized hosted in gneisses and amphibolites, which are cut by radial and ring dikes of granite porphyry with topaz, which are included in the Intrusive Suite Latest Granites of Rondônia (998-974 Ma). At least two distinct phases of primary tin mineralization are identified with zinnwaldita 40Ar/39Ar ages of 994 ± 3 Ma and 993 ± 3 Ma and is represented by lenses, veins and venules of quartz and pegmatite. The studied pegmatite occurs in the northeastern portion of the hill, where it appears hosted in breccias pipe and topaz rhyolite porphyry dike cut by topaz granite porphyry dike. It is a dike over 200 meters in length, thickness ranging 3-12 meters and general attitude N20E/45 ° SE. In the studied section in detail, the pegmatite shows a very distinct internal zoning, given by layers or beds sub concordant among themselves and with the walls of the dike. At least three zones were recognized based on the dominant mineralogy, they are from the wall to the ceiling: zone of quartz and topaz, zone of mica and feldspar, and granitic zone (quartz and feldspar).A possible fourth zone was not observed, but according to the miners, a bed with 10 cm thick of massive cassiterite occurs discontinuously along the wall of the body. The structure of the zones are massive and the granulation varies from medium to coarse in the granite zone and coarse to very coarse or giant (?) In the other two. The primary mineralogy is relatively simple: the quartz is gray to milky white, the... (Complete abstract click electronic access below)
Mestre

Made available in DSpace on 2015-06-17T19:34:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-02-26. Added 1 bitstream(s) on 2015-06-18T12:48:32Z : No. of bitstreams: 1 000830287.pdf: 2281849 bytes, checksum: 2a1c2e1cfc149a29c91a9d8e2700c302 (MD5)
Uma das maiores riquezas naturais do Brasil é o seu potencial mineral. A região amazônica é conhecida pela abundância de recursos minerais, podendo destacar o topázio, petróleo, e principalmente a cassiterita. Como consequência da mineração, o ecossistema vem sofrendo um processo constante de degradação. Um importante artifício na exploração de recursos minerais é a reabilitação e/ ou recuperação das áreas degradadas, para isso, é necessário estabelecer indicadores de degradação, assim como de qualidade do solo associada a sua biota, levando em consideração que esse é um ambiente dinâmico, heterogêneo e complexo de características físicas, químicas e biológicas diversificadas. Desse modo, o objetivo deste trabalho foi estudar a associação entre variáveis da atividade biológica do solo e variáveis morfométricas dos agregados, visando estabelecer uma função de pedotransferência para identificar de maneira expedita os melhores indicadores de recuperação para as áreas experimentais localizadas em substrato piso de lavra na Floresta Nacional do Jamari-RO.Os resultados apresentaram grande variabilidade no conjunto das variáveis morfométricas e uma menor dispersão dos dados para as variáveis biológicas. A metodologia de análise da amplitude das diferenças entre os parâmetros nas áreas analisadas permitiu a comparação entre as áreas em recuperação facilitando a interpretação gráfica das diferenças. Foi possível por meio da correlação canônica, determinar combinações lineares entre o conjunto de variáveis da diversidade biológica do solo e do conjunto das variáveis dos parâmetros morfométricos dos agregados do solo Considerando que o modelo das combinações lineares não apresentou um ajuste satisfatório, a definição de um índice expedito ficou comprometida, pois haveria necessidade de se estudar os problemas de multicolinearidade e intercorrelação entre as equações ...
One of the biggest natural wealth of Brazil is its mineral potential. The Amazon region is known for the abundance of mineral resources, and can highlight the topaz, oil, and especially tin. As a result of mining, the ecosystem has undergone a constant process of degradation. An important tool in the exploration of mineral resources is the rehabilitation and / or restoration of degraded areas, for this it is necessary to establish degradation indicators, as well as soil quality associated with its biota, taking into account that this is a dynamic environment, heterogeneous and complex physical, chemical and biological diverse. Thus, the objective of this work was to study the association between variables of biological soil activity and morphometric variables of households, aiming at a Pedotransfer function to identify expeditiously the best indicators of recovery for the experimental areas located in mining floor substrate the National Forest of Jamari-RO.Os results showed great variability in all the morphometric variables and a lower dispersion of data for biological variables. The analysis method of the amplitude differences between the parameters analyzed in the areas allowed the comparison of the areas facilitating recovery graphical interpretation of differences. It was possible through the canonical correlation determine linear combinations of the set of variables of soil biodiversity and to all the variables of the morphometric parameters of soil aggregates whereas the linear combination model has not submitted a satisfactory adjustment, the definition of an index expeditious been compromised, as there is need to study the problems of multicollinearity and intercorrelation between the predictive equations of biological activity through morphometric variables.

Submitted by FELIPE HASHIMOTO FENGLER null (felipe_fengler@hotmail.com) on 2018-03-09T01:06:32Z No. of bitstreams: 1 Tese_felipe_fengler_final.pdf: 3248053 bytes, checksum: b3102f65c7b76975b1871f465ba33210 (MD5)
Approved for entry into archive by Bruna Bacalgini null (bruna@sorocaba.unesp.br) on 2018-03-13T14:29:56Z (GMT) No. of bitstreams: 1 fengler_fh_dr_soro.pdf: 3248053 bytes, checksum: b3102f65c7b76975b1871f465ba33210 (MD5)
Made available in DSpace on 2018-03-13T14:29:56Z (GMT). No. of bitstreams: 1 fengler_fh_dr_soro.pdf: 3248053 bytes, checksum: b3102f65c7b76975b1871f465ba33210 (MD5) Previous issue date: 2018-03-05
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
No contexto do desenvolvimento sustentável há um paradigma crítico, que retrata a relação entre o capital e a degradação ambiental. Conforme aumenta o cunho socioeconômico de determinada atividade, maior é a permissibilidade da sociedade aos seus efeitos ambientais negativos, sobretudo quando são apenas sentidos em nível local. Porém, após um passado de exemplos adversos, a meta por um estado de equilíbrio tem adquiro notoriedade em busca de uma nova perspectiva de desenvolvimento. Quando atividades de grande relevância, como a mineração, resultam em elevado grau de alteração do meio, há expectativa da sociedade quanto à mitigação ou compensação dos seus efeitos negativos, principalmente quando ecossistemas sensíveis são afetados. Porém, a complexidade ambiental dificulta a mensuração da extensão dos danos ambientais, bem como a efetividade de ações de recuperação. Nesse contexto se insere o presente estudo. Buscaram-se métricas e métodos compreensivos para a avaliação de florestas em recuperação em áreas minerarias na Amazônia brasileira. A técnica de modelagem com Análise Dimensional foi empregada de maneira a estabelecer índices adimensionais voltados à avaliação desses ambientes. Variáveis relacionadas ao desenvolvimento florestal, fauna, além das condições físicas, químicas e bioquímicas do solo foram empregadas, utilizando a priori o processo de conhecimento por descoberta em banco de dados em sua seleção. Dois estudos preliminares a Análise Dimensional foram realizados, fornecendo suporte para escolha das variáveis e entendimento da representatividade dos índices adimensionais obtidos. Como resultado uma proposta metodológica foi apresentada, para avaliação da condição fitossociológica de ambientes em recuperação em comparação ao ecossistema de referência. O grau de alteração do solo se mostrou como um dos fatores condicionantes, destacando a importância das ações iniciais de preparo, preliminarmente ao plantio. A análise dimensional se revelou como uma abordagem promissora, possibilitando sintetizar, representar e comparar as condições ambientais dos locais minerados e do ecossistema de referência. Porém, três índices assumiram um papel protagonista, com representação sistêmica do processo de recuperação ambiental, o primeiro expresso pela relação entre duas variáveis bioquímicas do solo, a respiração basal e atividade celulase (Pi2); o segundo (Pi8) obtido através de variáveis biológicas da fauna e da flora; e o terceiro (Pi10), integrando variáveis do solo, da fauna e da flora. Os resultados obtidos permitiram condensar avanços conceituais e metodológicos nesse documento, estruturando uma base para elaboração de propostas de avaliação de ecossistemas alterados e estabelecimentos de padrões de qualidade com base no ecossistema de referência Amazônico.
There is a critical paradigm that portrays the sustainable development, the relationship between the capital and the environmental degradation. As the socioeconomic importance of a given activity increases, the greater will be the permissibility of society to its negative impacts, especially when they are only sensed at the local level. However, after several adverse examples in history, the aim for a state of equilibrium has acquired notoriety for a new perspective of development. When an activity of great relevance, as mining, results in high environmental alteration, there is an expectation of mitigation, or compensation, on its negative effects, especially when vulnerable ecosystems were affected. However, the environmental complexity not always allows a full comprehension of environmental damage, as well as the effectiveness of recovery actions in their reversal. This study aimed to search for comprehensive metrics and methods to evaluate of mined forests of Brazilian Amazonia. Dimensional Analysis was employed in establishing dimensionless index related to the environmental quality of the mined forests. Variables of forest development, fauna, and physical, chemical and biochemical conditions of the soil were employed, based on knowledge discovery in databases in its selection. Two preliminary studies to Dimensional Analysis were carried out, supporting the choice of variables and the further understanding about obtained dimensionless index. As a result, a methodological proposal was presented to evaluate the phytosociological conditions of recovering environments compared to the reference ecosystem. The degree of soil alteration was shown as a conditioning factor, highlighting the importance of the initial soil preparing actions, preliminary to revegetation. The dimensional analysis proved to be a promising approach, allowing synthesizing, representing and comparing the environmental conditions of the mined sites with the reference ecosystem. However, three indices played a major role, with systemic representation of the environmental recovery process, the first one expressed by the relationship between soil basal respiration and cellulase activity (Pi2), the second (Pi8), obtained through biological variables of fauna and flora; and the third (Pi10), integrating soil, fauna and flora variables. The obtained results allowed to condense conceptual and methodological advances in this document, structuring a basis for elaborating evaluation proposals for altered ecosystems and to establish quality standards, based on the reference ecosystem.

Orientador: Admilson Írio Ribeiro
Banca: Gerson Araújo de Medeiros
Banca: Fátima Conceição Márquez Piña-Rodrigues
Resumo: Uma das maiores riquezas naturais do Brasil é o seu potencial mineral. A região amazônica é conhecida pela abundância de recursos minerais, podendo destacar o topázio, petróleo, e principalmente a cassiterita. Como consequência da mineração, o ecossistema vem sofrendo um processo constante de degradação. Um importante artifício na exploração de recursos minerais é a reabilitação e/ ou recuperação das áreas degradadas, para isso, é necessário estabelecer indicadores de degradação, assim como de qualidade do solo associada a sua biota, levando em consideração que esse é um ambiente dinâmico, heterogêneo e complexo de características físicas, químicas e biológicas diversificadas. Desse modo, o objetivo deste trabalho foi estudar a associação entre variáveis da atividade biológica do solo e variáveis morfométricas dos agregados, visando estabelecer uma função de pedotransferência para identificar de maneira expedita os melhores indicadores de recuperação para as áreas experimentais localizadas em substrato piso de lavra na Floresta Nacional do Jamari-RO.Os resultados apresentaram grande variabilidade no conjunto das variáveis morfométricas e uma menor dispersão dos dados para as variáveis biológicas. A metodologia de análise da amplitude das diferenças entre os parâmetros nas áreas analisadas permitiu a comparação entre as áreas em recuperação facilitando a interpretação gráfica das diferenças. Foi possível por meio da correlação canônica, determinar combinações lineares entre o conjunto de variáveis da diversidade biológica do solo e do conjunto das variáveis dos parâmetros morfométricos dos agregados do solo Considerando que o modelo das combinações lineares não apresentou um ajuste satisfatório, a definição de um índice expedito ficou comprometida, pois haveria necessidade de se estudar os problemas de multicolinearidade e intercorrelação entre as equações...
Abstract: One of the biggest natural wealth of Brazil is its mineral potential. The Amazon region is known for the abundance of mineral resources, and can highlight the topaz, oil, and especially tin. As a result of mining, the ecosystem has undergone a constant process of degradation. An important tool in the exploration of mineral resources is the rehabilitation and / or restoration of degraded areas, for this it is necessary to establish degradation indicators, as well as soil quality associated with its biota, taking into account that this is a dynamic environment, heterogeneous and complex physical, chemical and biological diverse. Thus, the objective of this work was to study the association between variables of biological soil activity and morphometric variables of households, aiming at a Pedotransfer function to identify expeditiously the best indicators of recovery for the experimental areas located in mining floor substrate the National Forest of Jamari-RO.Os results showed great variability in all the morphometric variables and a lower dispersion of data for biological variables. The analysis method of the amplitude differences between the parameters analyzed in the areas allowed the comparison of the areas facilitating recovery graphical interpretation of differences. It was possible through the canonical correlation determine linear combinations of the set of variables of soil biodiversity and to all the variables of the morphometric parameters of soil aggregates whereas the linear combination model has not submitted a satisfactory adjustment, the definition of an index expeditious been compromised, as there is need to study the problems of multicollinearity and intercorrelation between the predictive equations of biological activity through morphometric variables.
Mestre

Dissertação (mestrado)—Universidade de Brasília, Instituto de Geociências, Programa de Pós-Graduação, 2014.
Submitted by Marília Freitas (marilia@bce.unb.br) on 2015-10-29T13:02:43Z No. of bitstreams: 1 2014_AnaRitaFelixSiqueira.pdf: 6264175 bytes, checksum: 6bbe57656d5940a6644ef42c7dcfb16d (MD5)
Approved for entry into archive by Raquel Viana(raquelviana@bce.unb.br) on 2015-12-15T18:29:16Z (GMT) No. of bitstreams: 1 2014_AnaRitaFelixSiqueira.pdf: 6264175 bytes, checksum: 6bbe57656d5940a6644ef42c7dcfb16d (MD5)
Made available in DSpace on 2015-12-15T18:29:16Z (GMT). No. of bitstreams: 1 2014_AnaRitaFelixSiqueira.pdf: 6264175 bytes, checksum: 6bbe57656d5940a6644ef42c7dcfb16d (MD5)
Os albititos mineralizados em estanho localizados nos garimpos Pelotas e Boa Vista, pertencentes à Província Estanífera de Goiás (PEG), cortam monzogranitos e tonalitos pertencentes à Suíte Aurumina e xistos da Formação Ticunzal. Os albititos são constituídos por albita, quartzo, cassiterita, apatita, K-feldspato e muscovita primária. Texturalmente apresentam alinhamento de “ripas” de albita e textura snowball, interpretados como texturas típicas de albititos de origem magmática. Os tonalitos, monzogranitos e xistos foram divididos em fácies: biotita-muscovita tonalito, muscovita-biotita tonalito, biotita-muscovita monzogranito, muscovita-biotita monzogranito, granada-clorita-biotita-quartzo xisto e grafita-clorita xisto. Os albititos são metaluminosos a peraluminosos, enquanto os monzogranitos e tonalitos são fortemente peraluminosos. Os albititos são enriquecidos em Na2O, Al2O3 e P2O5, contêm teores moderados de CaO e são empobrecidos em K2O, TiO2, Fe2O3 e MgO. Com relação aos elementos-traço, são enriquecidos em Sn, Ta, Rb, Nb e Zr e empobrecidos em Sr, Ba e Th. São enriquecidos em elementos terras raras leves (ETRL) em relação aos elementos terras raras pesados (ETRP). As anomalias de Eu são ausentes ou muito discretas, levemente positivas. Os tonalitos e monzogranitos são enriquecidos em TiO2, Fe2O3, MgO, CaO e K2O e empobrecidos em Al2O3, Na2O, P2O5, SnO2, TaO2, Rb, Nb e Zr. Os padrões de ETRs para os granitos e tonalitos mostram que são enriquecidos em ETRL e empobrecidos em ETRP. As anomalias de Eu para os monzogranitos são muito discretas, podendo ser levemente positivas ou negativas. Os tonalitos apresentam pronunciada anomalia positiva de Eu. Análises em microssonda eletrônica permitiram classificar a biotita do muscovita-biotita tonalito e do muscovita-biotita monzogranito como siderofilita, com razão Fe/(Fe+Mg) entre 0,58 a 0,71 a.f.u. e conteúdo de AlIV entre 2,1 a 3,3 a.f.u.. Composicionalmente, classifica-se como biotita de granitos peraluminosos. A muscovita dos albititos é mais enriquecida em Na2O e SiO2 e empobrecida em MgO, Fe2O3, Al2O3 e TiO2, e a muscovita da fácies biotita-muscovita tonalito é enriquecida em MgO, Fe2O3, Al2O3 e TiO2 e empobrecida em Na2O e SiO2. Os valores de TiO2 da muscovita secundária é sempre inferior a 0,5%. Entretanto, a muscovita primária possui teores variáveis de TiO2, desde quase nulos a 1%. A cassiterita é euedral a subedral, maclada, zonada e com forte pleocroísmo, com composições muito puras, com o Sn substituído principalmente por Nb e Ta. O plagioclásio apresenta composição de albita-oligoclásio (Ab77-99An22-1Or1) nos monzogranitos e de albita (Ab90-99An10-0,6Or0,4) nos tonalitos e albititos. A apatita é classificada como fluorapatita e é interpretada como sendo ígnea. Dados de isótopos de oxigênio em pares de albita e cassiterita mostraram que os albititos foram cristalizados em temperatura que varia de 653 a 1016ºC. As composições isotópicas do fluido calculadas para os albititos, 9,17 a 9,35‰ para o albitito do garimpo Pelotas e 8,66 a 9,72‰ para o albitito do garimpo Boa Vista, sugerem fluido de origem magmática. Valores de 40Ar/39Ar em muscovita dos albititos do garimpo Boa Vista resultaram em idade-platô de 1996,55±12,96 Ma, interpretada como idade da cristalização da muscovita. Esses dados geocronológicos permitem propor que os albititos da área foram formados durante o Paleoproterozóico, sendo correlacionados às fases tardias do magmatismo da Suíte Aurumina (2,12-2,17 Ga – U-Pb em zircão). Os dados mineralógicos, geoquímicos, de química mineral e isotópicos obtidos permitiram classificar as mineralizações de Sn hospedadas em albititos dos garimpos Pelotas e Boa Vista como magmáticas, associadas a um sistema granítico peraluminosos rico em boro, do tipo LCT. Os dados aqui apresentados permitem concluir que os albititos estudados são de origem magmática, tendo sido formados por cristalização de um magma altamente sódico, sendo que esse magma muito evoluído passou por vários processos de cristalização fracionada. Os tonalitos e monzogranitos mostraram-se também relativamente ricos em Na2O, o que é evidenciado pela química do plagioclásio. Essa composição pode estar ligada ao baixo grau de fusão de rochas metassedimentares que deram origem a essas rochas. A ordem de cristalização sugerida para as rochas estudadas é monzogranito-tonalito-albitito. Os resultados obtidos no presente trabalho demonstram que, além de conter mineralização de estanho hidrotermal, hospedada em greisens e geneticamente associada ao magmatismo granítico intraplaca de aproximadamente 1,7 Ga, a Província Estanífera de Goiás possui concentrações econômicas de estanho magmáticas, hospedadas em albitito ígneo e formadas por cristalização fracionada de granitos peraluminosos da Suíte Aurumina, de aproximadamente 2,0Ga. Esses resultados, portanto, ampliam as possibilidades de fonte de estanho na Província Estanífera de Goiás e têm implicações para o potencial econômico da Província. Estudos experimentais ou petrológicos adicionais devem ser realizados para avaliar a existência de relação genética entre o magmatismo intraplaca e o magmatismo sincolisional e, por conseguinte, entre a concentração hidrotermal e a magmática de estanho na Província Estanífera de Goiás. Sugerem-se, ainda, estudos para verificar o papel dos xistos da Formação Ticunzal na gênese dos granitos peraluminosos e na fonte de estanho na Província Estanífera de Goiás. ______________________________________________________________________________________________ ABSTRACT
The tin-mineralized albitites from the Pelotas and Boa Vista artisanal mines, in the Goiás Tin Province (GTP), cut the granites and tonalities from the Aurumina Suite and schists from the Ticunzal Formation. The albitites consist of albite, quartz, cassiterite, apatite, K-feldspar and primary muscovite. Texturally they contain alignment of albite “laths” and snowball texture, interpreted as typical of albitites from magmatic origin. The tonalites, granites and schists were divided in facies: biotite-muscovite tonalite, muscovite-biotite tonalite, biotite-muscovite monzogranite, muscovite-biotite monzogranite, garnet-chlorite-biotite-quartz schist and graphite-chlorite schist. The albitites are metaluminous to peraluminous,while the granites and tonalites are strongly peraluminous. The albitites are enriched in Na2O, Al2O3 and P2O5, contain moderate levels of CaO and are depleted in K2O, TiO2, Fe2O3 and MgO. With respect to trace elements, they are enriched in Sn, Ta, Rb, Nb and Zr and depleted in Sr, Ba and Th. The albitites are enriched in light rare earth elements (LREE) in relation to heavy rare earth elements (HREE). Eu anomalies are absent or very smooth and slightly positive. The tonalites and monzogranites are enriched in Al2O3, TiO2, Fe2O3, MgO, CaO and K2O and depleted in Na2O, P2O5, SnO2, TaO2, Rb, Nb and Zr. The REE patterns for the granites and tonalite shows enrichment in LREE and depletion in HREE. Eu anomalies for the monzogranites are very discrete and can be slightly positive or negative. The tonalites have a pronounced positive Eu anomaly. Microprobe analyzes allowed classifying the biotite from the muscovite-biotite tonalite and biotite-muscovite monzogranite as siderophyllite, with Fe/(Fe + Mg) between 0.58 to 0.71 a.f.u. and AlIV content between 2.1 and 3.3 afu. It is compositionally classified as biotite from peraluminous granites. Muscovite from the albitites have high SiO2 and Na2O contents and low MgO, Fe2O3, Al2O3 and TiO2, while muscovite from the biotite-muscovite tonalite facies are enriched in MgO, Fe2O3, TiO2 and Al2O3 and depleted in Na2O and SiO2. The TiO2 values of secondary muscovite are always less than 0.5%. However, primary muscovite has variable amounts of TiO2, from almost zero to 1%. Cassiterite forms strongly pleochroic, twinned and zoned euhedral to subhedral crystals, and has very pure composition, with Sn being replaced mostly by Nb and Ta. Plagioclase has composition of albite-oligoclase (Ab77-99An22-1Or1) in monzogranites and of albite (Ab90-99An10-0,6Or0,4) in the tonalites and albitites. Apatite is classified as fluorapatite,and is interpreted as igneous. Oxygen isotope data in pairs of albite and cassiterite showed thatalbitites were crystallized in a temperature range of 653-1016°C. The isotopic compositions of the fluid calculated for the albitites, 9.17 to 9.35‰ for Pelotas mine and from 8.66 to 9.72‰ for the Boa Vista mine, suggest that the fluid is of magmatic origin. 40Ar/39Ar values obtained in muscovite from albitite of the Boa Vista mine resulted in plateau age of 1996.55 ± 12.96 Ma, interpreted as the crystallization age of the muscovite. This allows the proposition that albitites have been formed during the Paleoproterozoic, and can be correlated with the late stages of the Aurumina magmatic Suite (2.12 to 2.17 Ga - U-Pb zircon). The mineralogical, geochemical and isotopic data obtained in this research allow classify the tin mineralization hosted in the albitites of Pelotas and Boa Vista mines as magmatic, associated with a peraluminous granitic system rich in boron, of LCT type. The data presented here allow conclude that the studied albitites are of magmatic origin, formed by crystallization of a highly evolved and sodic magma, and which underwent various steps of fractional crystallization. Tonalites and monzogranites are also relatively rich in Na2O, which is evidenced by plagioclase chemistry. This composition may be related to low amount of fusion of the metasedimentary rocks that gave rise to these rocks. The crystallization order suggested for the studied rocks is monzogranite-tonalite-albitite. The results obtained in this study demonstrate that, besides containing hydrothermal tin mineralization, hosted in greisen and genetically associated with the granitic intraplate magmatism of approximately 1.7 Ga, the Goiás Tin Province has economic concentration of magmatic tin, hosted in igneous albitite formed by fractional crystallization of peraluminous granites from the Aurumina suite, of approximately 2.0 Ga. These results thus increase the possibilities of tin source in the Goiás Tin Province and have implications for the economic potential of the Province. Additional petrological or experimental studies are encouraged to evaluate the existence of genetic relationship between the intraplate and sin-colisional magmatism and, therefore, between hydrothermal and magmatic concentration of tin in the Goiás Tin Province. Further studies to verify the role of the Ticunzal Formation schists in the genesis of the peraluminous granites and tin in the Goiás Tin Province are also suggested.

Submitted by Teresa Cristina Rosenhayme (teresa.rosenhayme@cprm.gov.br) on 2017-01-31T14:51:30Z No. of bitstreams: 1 Tese Cassiano Costa Castro.pdf: 21940488 bytes, checksum: 9b9f8e4a221aa6064c382cac8c62eaeb (MD5)
Approved for entry into archive by Jéssica Gonçalves (jessica.goncalves@cprm.gov.br) on 2017-02-01T19:14:43Z (GMT) No. of bitstreams: 1 Tese Cassiano Costa Castro.pdf: 21940488 bytes, checksum: 9b9f8e4a221aa6064c382cac8c62eaeb (MD5)
Approved for entry into archive by Jéssica Gonçalves (jessica.goncalves@cprm.gov.br) on 2017-02-01T19:16:51Z (GMT) No. of bitstreams: 1 Tese Cassiano Costa Castro.pdf: 21940488 bytes, checksum: 9b9f8e4a221aa6064c382cac8c62eaeb (MD5)
Made available in DSpace on 2017-02-01T19:17:28Z (GMT). No. of bitstreams: 1 Tese Cassiano Costa Castro.pdf: 21940488 bytes, checksum: 9b9f8e4a221aa6064c382cac8c62eaeb (MD5) Previous issue date: 2016

Esta dissertação teve como objetivo a implantação do método de datação U-Pb em cassiterita no Centro de Pesquisas Geocronológicas da Universidade de São Paulo. Para tanto, utilizaram-se amostras da mineralização estanífera da Subprovincia do Rio Paranã, extremo nordeste do Estado de Goiás. A área compreende unidades de idade mínima transamazônica, representadas pelo Complexo Granito-Gnáissico e pela Formação Ticunzal, superpostas por metassedimentos predominantemente psamíticos do Grupo Araí, com idade aproximada de 1.770 Ma, e intrudidos por granitóides estaníferos paleo a mesoproterozóicos. Pegmatitos alojados nas duas primeiras unidades correspondem a outras manifestações da mineralização de estanho na subprovíncia. Datações pelo método K-Ar em muscovita situaram a idade da mineralização nos pegmatitos entre cerca de 2.000 Ma e 2.130 Ma. As análises por U-Pb na cassiterita confirmaram estes valores na maior parte dos casos. Quanto aos granitóides, uma idade U-Pb em cassiterita de 1.535\'+OU-\'57 Ma foi obtida. A metodologia U-Pb em cassiterita mostrou-se útil, desde que tomadas precauções como a análise de várias amostras distintas e a caracterização mineral prévia da fase, a fim de selecionar amostras isentas de inclusões de minerais portadores de Pb. Datações pelo método Pb-Pb resultaram incorretas na maior parte das vezes em função de excesso de Pb comum derivado de inclusões, especialmente de feldspato. A composição isotópica de Pb mais radiogênica foi verificada em cassiterita de rocha granitóide, analogamente ao reportado em Gulson & Jones (1992), sugerindo que o método pode ter melhor resposta se aplicado em mineralizações neste tipo de rocha. Caracterizou-se a ocorrência de pelo menos duas fácies distintas mineralizadas nos pegmatitos, com base na natureza de suas inclusões.
The purpose of this work was to set up the cassiterite U-Pb method of dating at Centro de Pesquisas Geocronologicas of Universidade de São Paulo. Samples of tin mineralization from the subprovíncia do Rio Paranã, Goiás State, were used to perform the experience. The area includes units of transamazonian minimum ages, represented by complexo Granito-Gnáissico and formação Ticunzal , overlayed by metamorphosed sandstones mainly, with ages close to 1.770 Ma, and intruded by paleo to mesoproterozoic tin granites. Pegmatites that cut the first and second units correspond to another manifestation of tin mineralization in the area. Muscovite K-Ar ages situated the pegmatites mineralization between 2,000 Ma and 2,130 Ma. The cassiterite U-Pb analyses confirmed these values in most cases. In relation to the granitoids, one single U-Pb age in cassiterite of 1,535 \'+ ou -\' 57 Ma was obtained. The cassiterite U-Pb methodology proved useful since caution is taken, as dating of many distinct samples and mineralogical characterization of the phase prior to dating in order to select samples without inclusions of pb-bearing minerals. The most radiogenic isotopic composition of Pb was verified in cassiterite from a granitoid rock, in analogy to what was reported by Gulson & Jones (1992). This suggests that the method can give better results if applied to mineralization in such rocks. The occurrence of at least two mineralized distinct facies was characterized in the pegmatites, based on its inclusions peculiarities.

A indústria produtora de estanho e chumbo metálicos localizada em Pirapora do Bom Jesus, estado de São Paulo é responsável pela produção anual de cerca de 7000 toneladas de estanho e 350 toneladas de chumbo. A matéria prima utilizada nesse processamento é a cassiterita a qual apresenta em sua composição concentrações de radionuclídeos naturais de urânio e tório de 660 kBq kg-1 e 450 kBq kg-1 respectivamente. O processamento metalúrgico de redução e refino permite que esses radioanuclídeos fiquem concentrados principalmente no material particulado gerado pelas chaminés e pela dispersão da escória gerada que é estocada a céu aberto. A quantidade dessa escória rejeito atualmente estocada é estimada em 600000 toneladas. Esse trabalho pretende estudar o impacto radiológico ambiental da operação desse processamento e estabelecer seu Programa de Monitoramento Radiológico Ambiental (PMRA). Visando à realização desse trabalho, os contaminantes radioativos foram determinados na matéria prima, produtos, subprodutos, resíduo, lagoas e sistemas de exaustão. Na matéria prima os radionuclídeos provenientes da série de decaimento do urânio e do tório, apresentam-se praticamente em equilíbrio; durante o processamento esse equilíbrio é quebrado e os radionuclídeos migram de acordo com suas propriedades químicas. Concentrações de 31 kBq kg-1 para 238U, 69 kBq kg-1 para 226Ra, 2.5 kBq kg-1 para 210Pb, 130 kBq kg-1 para 232Th e 120 kBq kg-1 para 228Ra foram obtidas para escória rejeito. O impacto radiológico ambiental foi estabelecido pelo monitoramento dos radionuclídeos nos compartimentos críticos os quais podem causar doses de exposições ao público. Se a pilha de escória rejeito for considerada, os caminhos críticos são a exposição interna devido à inalação da poeira e a ingestão de água, decorrentes da re-suspensão e dispersão da pilha e da contaminação do lençol freático, respectivamente. Exposições externas se devem à imersão na nuvem radioativa e aos solos contaminados. Para a emissão de efluentes gasosos e materiais particulados das chaminés, os caminhos críticos são a exposição interna oriunda da inalação do radônio e exposição externa devido à imersão na nuvem radioativa e ao solo contaminado. As matrizes ambientais críticas definidas foram: águas subterrâneas, solo e ar, e os radionuclídeos U, Th, 226Ra, 228Ra e 210Pb.
The tin and lead industry located in Pirapora do Bom Jesus in the state of São Paulo, Brazil, is responsible for the production of about 7000 ton year-1 of tin and 350 ton year-1 of lead. The raw material used in this facility is cassiterite, which presents in its composition concentrations of natural radionuclides from the uranium and thorium series up to 660 kBq kg-1 and 450 kBq kg-1, respectively. The smelting and refining processes may lead to concentrations of these radionuclides, mainly in the precipitated dust and in slag. In the operational process, intermediate refining and final slag are obtained and are stored in piles in open air. It is estimated that the amount of waste stored is about 600000 ton. This work aims to study the environmental radiological impact of the operation of this facility and to establish its Environmental Radiological Monitoring Program. In order to accomplish this task the content of radioactivity was determined in the raw material, products, byproducts, residue, deposition pond and exhausting systems. Although in the raw material the radionuclides from the uranium and thorium series are almost in equilibrium, during the processing this equilibrium is disrupted and the radionuclides migrate according to their chemical properties. Concentrations up to 31 kBq kg-1 for 238U, 69 kBq kg-1 for 226Ra, 2.5 kBq kg-1 for 210Pb, 130 kBq kg-1 for 232Th and 120 kBq kg-1 for 228Ra were obtained in the slag. The environmental radiological impact was established by measuring the radionuclides in the critical compartments that is the ones that may cause exposure to the public. If the residue pile is considered, the critical pathways are the internal exposition from the dust inhalation and the water ingestion, due to re suspension and dispersion of the pile dust and groundwater contamination, respectively; and external exposure due to immersion in the radioactive cloud and soil contamination. For the emission of gaseous and particulate effluents from the chimneys, the critical pathways are the internal exposition from the radon inhalation and external exposure due to immersion in the radioactive cloud and due to soil contamination. The environmental matrices defined as critical were: ground water, soil and air; and the critical radionuclides were U, Th, 226Ra, 228Ra and 210Pb.

Made available in DSpace on 2014-06-11T19:23:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-07-22Bitstream added on 2014-06-13T20:50:10Z : No. of bitstreams: 1 yada_mm_me_jabo.pdf: 312702 bytes, checksum: 6f892253bdb3bc5c70ef4a35150b6ce5 (MD5)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Os recursos naturais fazem da região amazônica um importante pólo para a agricultura e a exploração mineral. Entretanto, a falta de moderação na exploração causa a diminuição da matéria orgânica do solo com perda de seu potencial produtivo ou de regeneração da mata nativa. A recuperação destas áreas é de fundamental importância até mesmo para a manutenção da atividade física, química e biológica do solo. O plano de recuperação das áreas degradadas iniciou em 1997, uma série de pesquisas com a finalidade de definir estratégias para recuperação da área degradada por mineração de cassiterita na Floresta Nacional do Jamari, em Rondônia. As áreas foram classificadas em diferentes níveis de recuperação. O presente trabalho teve por objetivo avaliar os atributos químicos e bioquímicos nos solos das áreas degradadas pela mineração de cassiterita submetidos aos processos de recuperação nas minas Serra da Onça e Santa Maria. As análises dos atributos químicos e bioquímicos do solo contribuem para a caracterização das áreas degradadas por mineração em processo de recuperação podendo identificar áreas que estão em estágio avançado de recuperação comparado com as áreas de mata e de capoeira
The situation and the environmental resources of Amazon Basin make it import for agriculture and mineral extraction, both causing the destruction of soil organic matter with the loss of the soil fertility, that it became improper to agriculture of is not able to support the restore of the native forest. The recuperation of these areas is important for the maintenance of the physical, chemical and biological activity of the soil and plant growth. The plan of recuperation of degraded areas started in 1997, in a research with the purpose to define strategies for a process of recuperation of the area degraded by mining of tin ore in the National Forest of Jamari, Rondônia state. Different areas had been classified in according to their level of recuperation. The objective of this work was to evaluate chemical and biochemical attributes in soils of degraded areas submitted to mining of tin ore in different stages of restoring process in Amazon Basin. The analyses of quantification of chemistry and biochemistry attributes in degraded soils submitted to recuperation program contribute for the characteristic of the different areas

Orientador: Wanderley José de Melo
Banca: Mara Cristina Pessoa da Cruz
Banca: Elcio Liborio Balota
Resumo: Os recursos naturais fazem da região amazônica um importante pólo para a agricultura e a exploração mineral. Entretanto, a falta de moderação na exploração causa a diminuição da matéria orgânica do solo com perda de seu potencial produtivo ou de regeneração da mata nativa. A recuperação destas áreas é de fundamental importância até mesmo para a manutenção da atividade física, química e biológica do solo. O plano de recuperação das áreas degradadas iniciou em 1997, uma série de pesquisas com a finalidade de definir estratégias para recuperação da área degradada por mineração de cassiterita na Floresta Nacional do Jamari, em Rondônia. As áreas foram classificadas em diferentes níveis de recuperação. O presente trabalho teve por objetivo avaliar os atributos químicos e bioquímicos nos solos das áreas degradadas pela mineração de cassiterita submetidos aos processos de recuperação nas minas Serra da Onça e Santa Maria. As análises dos atributos químicos e bioquímicos do solo contribuem para a caracterização das áreas degradadas por mineração em processo de recuperação podendo identificar áreas que estão em estágio avançado de recuperação comparado com as áreas de mata e de capoeira
Abstract: The situation and the environmental resources of Amazon Basin make it import for agriculture and mineral extraction, both causing the destruction of soil organic matter with the loss of the soil fertility, that it became improper to agriculture of is not able to support the restore of the native forest. The recuperation of these areas is important for the maintenance of the physical, chemical and biological activity of the soil and plant growth. The plan of recuperation of degraded areas started in 1997, in a research with the purpose to define strategies for a process of recuperation of the area degraded by mining of tin ore in the National Forest of Jamari, Rondônia state. Different areas had been classified in according to their level of recuperation. The objective of this work was to evaluate chemical and biochemical attributes in soils of degraded areas submitted to mining of tin ore in different stages of restoring process in Amazon Basin. The analyses of quantification of chemistry and biochemistry attributes in degraded soils submitted to recuperation program contribute for the characteristic of the different areas
Mestre

Este trabalho, complementado por documentação geológica da região do depósito e por uma revisão não só dos métodos clássicos de avaliação de reservas como também dos conceitos e técnicas de amostragem na pesquisa mineral, apresenta os resultados de um estudo comparativo de amostragem em furos de sondagem e em galerias para pesquisa de cassiterita no Pegmatito Xupé, em Monte Alegre de Goiás, GO. Os corpos pegmatíticos, por exibirem grande variabilidade natural dificultam os processos de amostragem e pesquisa, que, não obstante isso, são de vital importância, quando se pensa no aproveitamento industrial dessa fonte de vários metais raros. Os estudos mostram existir grande diferença de teores médios de estanho nos furos de sondagem e em galeria: basta, para isso, observar a redução constante da variância em face da relação fundamental da amostragem: volume x variância. Para corpos pegmatíticos constatou-se que a amostragem de grande massa é a mais indicada, e os resultados analíticos de furos de sondagem devem ser vistos apenas como valores indicativos, mas importantes, numa rápida visualização tridimensional do corpo mineral. Com os dados levantados no inventário da pesquisa mineral, a avaliação de reservas do Pegmatito Xupé, pelo método dos perfis padrão, é da ordem de 415000 m³ de minério com 1695 g de Sn/m³ e 53 g de \'Ta IND. 2\'\'O IND. 5\'/m³.
This paper presents the results of a comparative statistic study between drill hole sampling and drift\'s channel sampling results carried out during the underground exploration and ore reserve evaluation in the Xupé pegmatite - Monte Alegre de Goiás - State of Goiás. The complete geological documentation available in the area, a revision of classical methods for ore reserve estimation and a revision of concepts and techniques of sampling are also presented in this dissertation. The pegmatite ore bodies usually exhibit a large natural grade variability. In this way the sampling procedures are not easy to acomplish being of capital importance for the appropriate evaluation and industrial use as a source of rare metals. When both drill hole and drift Sn grade results are compared, large differences of the average grade are noticed. This is true because of the inverse correlation between variance and sample volume which keeps the fundamental relation of sampling: volume x variance = constant. It is concluded that bulk sampling is most indicated for Sn pegmatite ore bodies evaluation and the grade values obtnined from drill cores should be used to delineate the tridimensional geometry and ore limits. Measured and indicated reserves are of the order of 415000 m³, with 1695 g Sn/m³ and 53 g \'Ta IND. 2\'\'O IND. 5\'/m³.

Submitted by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-10-18T13:07:35Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação_Ceel_Daniel v. final.pdf: 755892 bytes, checksum: 8ca0050ccfda37667546ba899bfccdf0 (MD5)
Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-10-18T13:07:46Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação_Ceel_Daniel v. final.pdf: 755892 bytes, checksum: 8ca0050ccfda37667546ba899bfccdf0 (MD5)
Made available in DSpace on 2018-10-18T13:07:46Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação_Ceel_Daniel v. final.pdf: 755892 bytes, checksum: 8ca0050ccfda37667546ba899bfccdf0 (MD5) Previous issue date: 2018-08-30
The use of rare earth as raw material for industry has grown rapidly, with great technological applicability, especially in the areas of chemistry, electronics, metallurgy, materials and others. Due to the fact that technology industry, the demands on reliability and speed of chemical analysis have increased considerably. Among analytical techniques capable of analyzing rare earth concentration, wavelength dispersion X-ray fluorescence (WDXRF) provides qualitative and quantitative results quickly with high accuracy. However, the reliability of this technique depends on the correction of some factors, such as matrix effect. This work proposes a methodology for the chemical analysis of the rare earths elements La, Ce, Nd, Gd and Sm by WDXRF in the tailing of the cassiterite from the Pitinga mine (AM, Brazil). About 10 kg of the mining tailing sample was collected shortly after the ore processing in the mine's industrial plant. The quantification was based on the use of the mathematical method of matrix effect correction by empirical coefficients of influence. In addition, analyzes of the mineralogical phases of the sample were carried out by X-ray diffraction and chemical characterization of the major elements from tailings. The evaluation of the quality of the proposed methodology revealed high compliance with the expected values of the reference materials used. Finally, the existence of relevant quantities of rare earth present in the cassiterite tailings were identified in this work.
O uso de terras raras como matéria-prima para indústria cresceu aceleradamente, com grande aplicabilidade tecnológica, sobretudo nas áreas da química, eletrônica, metalúrgica, de materiais entre outras. Por se tratar de uma indústria de tecnologia, as exigências na confiabilidade e a rapidez das análises químicas aumentaram consideravelmente. Dentre as técnicas analíticas capazes de analisar a concentração de terras raras, a fluorescência de raios X por dispersão de comprimento de onda (WDXRF) oferece resultados quali-quantitativos de forma rápida, precisa e de elevada exatidão. Contudo, a confiabilidade dessa técnica depende da correção de alguns fatores, como o efeito de matriz. Este trabalho propõe uma metodologia de análises químicas dos elementos terras raras La, Ce, Nd, Gd e Sm por WDXRF em rejeito do beneficiamento da cassiterita proveniente da mina do Pitinga (AM, Brasil). Cerca de 10 kg da amostra foram coletados do rejeito logo após o processo de beneficiamento da cassiterita na planta industrial da mina. A quantificação foi baseada na utilização do método matemático de correção do efeito de matriz por coeficientes de influência empíricos. Adicionalmente, foram realizadas análises das fases mineralógicas da amostra por difração de raios X e de caracterização química dos elementos maiores do rejeito. A avaliação da qualidade da metodologia proposta revelou elevada conformidade com os valores esperados dos materiais referência utilizados. Finalmente, a existência de quantidades relevantes de terras raras presentes no rejeito da cassiterita foram identificadas neste trabalho.

Submitted by Cleide Dantas (cleidedantas@ufpa.br) on 2018-11-30T16:52:44Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_MorfologiaQuimicaMineral.pdf: 7472605 bytes, checksum: 48ddf3a46bbdad4f54448eeba39a1bb4 (MD5)
Approved for entry into archive by Cleide Dantas (cleidedantas@ufpa.br) on 2018-11-30T16:53:46Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_MorfologiaQuimicaMineral.pdf: 7472605 bytes, checksum: 48ddf3a46bbdad4f54448eeba39a1bb4 (MD5)
Made available in DSpace on 2018-11-30T16:53:46Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_MorfologiaQuimicaMineral.pdf: 7472605 bytes, checksum: 48ddf3a46bbdad4f54448eeba39a1bb4 (MD5) Previous issue date: 2018-07-23
Os conteúdos de elementos-traço em determinados minerais podem ajudar a revelar processos tectônicos, petrológicos, hidrotermais ou intempéricos aos quais foram submetidos. O zircão, além de ser um mineral acessório comum, química e fisicamente resistente a transporte sedimentar e a processos intempéricos, metamórficos de alta temperatura e de anatexia, apresenta certos elementos-traço em sua estrutura que tem permitido associá-lo ao seu tipo de rocha-fonte, seu ambiente de cristalização e a determinados depósitos minerais. Teores elevados de Hf e baixas razões Zr/Hf em zircões são características de granitos mineralizados em Sn e metais associados (Nb, Ta, ETR, etc.). Concentrações de Y e Nb, elementos pouco móveis em meio aquoso, em granitos tipo A são utilizados como bons indicadores da natureza crustal ou juvenil dos magmas a partir dos quais essas rochas cristalizaram. Cristais de zircão tendem a incorporar Y e Nb em sua estrutura e podem apresentar razões Y/Nb próximas a razão inicial do seu magma gerador. A partir da morfologia e composição de cristais detríticos de zircão é possível estimar a distância de transporte da amostra à sua fonte. As composições químicas de cassiteritas também podem ser utilizadas para indicar fontes e processos geradores. O presente trabalho é baseado em imagens de MEV e em análises semiquantitativas por EDS (Energy Dispersive Spectrometry) de cristais detríticos de zircão e cassiterita provenientes de concentrados de bateia da Província Estanífera de Rondônia (PER). O objetivo principal é caracterizar as fontes desses minerais, confirmar a localização de depósitos em exploração e indicar áreas potenciais para a prospecção de Sn e metais associados. A utilização de morfologia e química mineral de grãos detríticos em escala regional podem funcionar como uma ferramenta rápida e eficiente para a prospecção de determinados bens minerais. A área de trabalho, localizada na PER, porção centro-norte do Estado de Rondônia, está contida nas folhas Alto Jamari SC-20-Y-B e Ariquemes SC-20-V-D, ambas mapeadas pela CPRM na escala 1:250.000. As amostras de concentrados de bateia, oriundas desses projetos, foram coletadas em drenagens ativas, a partir de um volume de 20 litros de sedimentos retidos em peneiras de 5 e 0,5 mm. A partir desses concentrados foram separados minerais pesados por microbateamento com água, utilizando líquidos pesados (bromofórmio), realizada separação magnética através de ímã de Nd de mão, e separados cristais de zircão (cem grãos) e cassiterita (todos os grãos triados em 5g de amostra de concentrado) utilizando uma lupa binocular, além de critérios como cor, granulometria e morfologia representativas das populações desses minerais. Posteriormente, foram confeccionados mounts de zircão e cassiterita para análises por MEV-EDS. Os cristais de zircão com teores de Hf >3% foram interpretados como provenientes de rochas com elevado potencial a mineralizações em Sn e metais associados. Esses cristais foram utilizados no tratamento geoestatístico e comparados com o posicionamento geográfico de minas e garimpos de Sn, conhecidos na área de estudo, para aferir a veracidade do método. O tratamento geoestatístico utilizou o método de krigagem ordinária e, a partir dos resultados, foram geradas curvas de isoteores. Os mapas de isoteores, utilizando razões Zr/Hf em zircões detríticos de concentrados de bateia se mostraram eficientes, pois coincidiram com depósitos de cassiterita conhecidos na região. Na área selecionada para este estudo identificou-se uma variedade morfológica e composicional significativa dos grãos detríticos de zircão. Mesmo nos cristais mais enriquecidos em Hf (Hf>3%), esses teores e suas razões Zr/Hf variam consideravelmente. Os cristais mais alterados tendem a ser mais enriquecidos em Hf e a apresentar razões Zr/Hf mais baixas, são mais fraturados e frágeis ao transporte, indicando fontes proximais. Por outro lado, os grãos menos alterados possuem baixos teores de Hf, altas razões Zr/Hf e se mostram pouco a moderadamente arredondados, indicando fontes proximais a intermediárias. Enquanto Zr e Hf são variáveis dentro do mesmo grão, os teores de Y e Nb são praticamente constantes. No diagrama ternário Hf-Nb-Y, percebe-se que os zircões aqui estudados são enriquecidos em Nb e empobrecidas em Y, enquanto na Província Estanífera do Sul do Pará (PESP) e Pitinga apresentam comportamento inverso. Os altos valores de Nb nos zircões deste trabalho e os de Y na PESP são aqui interpretados como uma resposta da fonte magmática onde foram formados. Enquanto os zircões da PER são oriundos de rochas com valores de eNd(t) positivos a próximos de zero, os valores de eNd(t) da PESP são fortemente negativos. Assim, pode-se admitir que zircões com altas razões Y/Nb seriam provenientes de fontes dominantemente crustais, enquanto zircões com baixas razões Y/Nb teriam como origem fontes mistas (crustais e mantélicas). Os cristais de cassiterita deste estudo são prismáticos ou granulares, com terminações piramidais, bordas embaiadas sugerindo transporte sedimentar ausente a moderado. Possuem alto teor de pureza (Sn entre 73 e 79%), com concentrações de cátions substituintes do Sn em torno de 1,5%. Os altos teores relativos de Nb e Ta indicam fontes magmáticas e os tores subordinados de Ti e Fe mostram o estágio hidrotermal em que estes minerais foram gerados.
The contents of trace elements in certain minerals could help to revels tectonic, petrologic, hydrothermal or weathering processes which it was submitted. In addition to being a common accessory mineral, chemically and physically resistant to sedimentary transport and weather, high temperature metamorphic processes and anatexia, the abundance of certain trace elements in igneous zircons has allowed a connection with its type of rock source, its environment of crystallization and with certain mineral deposits. High levels of Hf and low Zr / Hf ratios in zircons are characteristic of mineralized granites in Sn and associated metals (Nb, Ta, ETR, etc.). Concentrations of Y and Nb, elements slightly mobile in aqueous environment, of granites type A can be used as good indicators of the crustal or juvenile nature of the magmas from which these rocks crystallized. Zircon crystals tend to incorporate Y and Nb in their structure and may present Y / Nb ratios close to the initial ratio of their generating magma. From the morphology and composition of zircon detrital crystals, it is possible to estimate the number of sedimentary rocks in the active river beds and their transport distance. The chemical compositions of cassiterites can also be used to indicate sources and generating processes. The present work is based on MEV images and semiquantitative analyzes by EDS (Energy Dispersive Spectrometry) of zircon and cassiterite detrital crystals from baton concentrate of the Rondônia Tin-Province (RTP). The main objective is to characterize the sources of these minerals, to confirm the location of deposits in exploration and to indicate potential areas for the prospection of Sn and associated metals. The use of morphology and mineral chemistry of detrital grains on a regional scale could be used as a fast and efficient tool for the prospecting of certain mineral goods. The work area, located in RTP, north-central portion of State Rondônia, is contained in the sheets Alto Jamari SC-20-Y-B and Ariquemes SC-20-V-D, both mapped by CPRM in the 1: 250,000 scale. Samples of baton concentrate from these projects were collected in active drainage from an initial volume of 20 liters of sediment retained between strainer of 5 and 0.5 mm. From these concentrates, light minerals were separated by micro-batting with water, heavy liquids (bromoform), magnetic by hand Nd magnet, and crystals of zircon (one hundred grains) and cassiterite (all grains screened in 5g of concentrate) using a binocular loupe, in addition of criteria such as color, granulometry and morphology representative of the populations of these minerals. Subsequently, zircon and cassiterite mounts were prepared for MEV / EDS analysis. The zircon crystals with contents of Hf>3% were interpreted as coming from rocks with high potential to mineralization in Sn and associated metals. These crystals were used in the geostatistical treatment and compared with the geographic positioning of mines and digging of Sn, known in the study area, to verify the veracity of the method. The geostatistical treatment used the ordinary kriging method and, from the results, isoteores curves were generated. The isothermal maps, using Zr / Hf ratios in detrital zircons of baton concentrate, were efficient because they coincided with known cassiterite deposits in the region. In the area selected for this study a significant compositional and morphological variety of zircon detrital grains were identified. Even in the most Hf enriched crystals (Hf>3%), these contents and their Zr / Hf ratios vary strongly. The most altered crystals tend to be more enriched in Hf and have lower Zr / Hf ratios, are more fractured and fragile to transport, indicating proximal sources. On the other hand, the less altered grains have low Hf contents, high Zr / Hf ratios and show little to moderately rounded, indicating proximal to intermediate sources. While Zr and Hf are variable within the same grain, the contents of Y and Nb are virtually constant. In the ternary diagram Hf-Nb-Y, the zircons of the RTP are enriched in Nb and impoverished in Y, while in the South of Pará Tin-Province (SPTP) and Pitinga they present Y enrichment and Nb impoverishment. The high values of Nb in the zircons of RTP and those of Y in the SPTP are interpreted here as a response of the magmatic source where they were formed. While the zircons of RTP are from rocks with positive εNd (t) values close to zero, the εNd (t) values of the SPTP are strongly negative. Thus, it can be assumed that zircons with high Y / Nb ratios would come from predominantly crustal sources, while zircons with low Y / Nb ratios would have mixed (crustal and mantle) sources. Cassiterite crystals of this study are prismatic or granular, with pyramidal terminations, bordered edges, suggesting absente to moderate sedimentary transport. They have high purity content (Sn between 73 and 79%) with concentrations of substitution cations of Sn around 1.5%. The high relative contents of Nb and Ta indicate magmatic sources and the subordinate Ti and Fe contents show the hydrothermal stage in which these minerals were generated.
CPRM - Companhia de Pesquisa de Recursos Minerais / Serviço Geológico do Brasil

Made available in DSpace on 2014-12-12T01:01:15Z (GMT). No. of bitstreams: 1 000463985-Texto+Completo-0.pdf: 1555769 bytes, checksum: b82a6402339c447066face4bc6b70629 (MD5) Previous issue date: 2014
This work is the result of at least ten years of research since the development of the project, to the first interview and first cataloged documents in Historical Documentation Center of the Court of Rondônia. It discusses the social and economic relations in the current City of Itapuã do Oeste and the Jamari National Forest area, in the period that includes the mid 50s until the late 90s of XX century. During this period cassiterite comes to occupy a prominent place in the local economy since the rubber loses its economic importance in the region and its value in the international market. The end of manual mining in 1971 attracted for the region national companies and multinational groups, which changed some aspects of mineral exploration and working relationships in order to make them more human than they were in the days of the rubber and later of the mines. With the emergence of Itapuã do Oeste in the late 70 the differences between Itapuã do Oeste and the Jacundá Mining are immense in terms of the basic structures of care for the population, such as sanitation, prevention of endemic diseases, public lighting, education, etc. But with the breakdown of cassiterite in 1989/1990 in the international market, the cassiterite mining underwent a process of adaptation to the new reality imposed by the market, so a significant part of the population of Jacundá Mining that has not been fired began to settle in the Itapuã do Oeste at a time when the district Itapuã do Oeste is elevated to municipality.
O presente trabalho é o fruto, de pelo menos, dez anos de pesquisa desde a elaboração do projeto, a primeira entrevista e os primeiros documentos catalogados no Centro de Documentação Histórica do Tribunal de Justiça de Rondônia. Trata sobre as relações sociais e econômicas na área do atual Município de Itapuã do Oeste e da Floresta Nacional do Jamari, no período que compreende meados dos anos 50 até o final da década de 90 do século XX. Nesse período a cassiterita passa a ocupar lugar de destaque na economia local, já que a borracha perde sua importância econômica na região e seu valor no mercado internacional. O fim do garimpo manual em 1971 atraiu para a região empresas nacionais e grupos multinacionais, que mudaram alguns aspectos da exploração mineral e as relações de trabalho, de modo a torná-las mais humanas do que eram nos tempos dos seringais e posteriormente dos garimpos. Com o surgimento do povoado de Itapuã do Oeste no final dos anos 70 as diferenças entre Itapuã do Oeste e a Mineração Jacundá são imensas do ponto de vista das estruturas básicas de atendimento à sua população, tais como: saneamento básico, prevenção às doenças endêmicas, iluminação pública, educação, etc. Porém, com a quebra da cassiterita entre 1989/1990, no mercado internacional, a mineração de cassiterita viveu um processo de adaptação à nova realidade imposta pelo mercado, assim uma parte significativa da população da Mineração Jacundá que não foi demitida passou a fixar residência no distrito de Itapuã do Oeste em um momento que o distrito é elevado à condição de Município.

Made available in DSpace on 2015-04-14T13:48:20Z (GMT). No. of bitstreams: 1 463985.pdf: 1555769 bytes, checksum: b82a6402339c447066face4bc6b70629 (MD5) Previous issue date: 2014-11-05
This work is the result of at least ten years of research since the development of the project, to the first interview and first cataloged documents in Historical Documentation Center of the Court of Rond?nia. It discusses the social and economic relations in the current City of Itapu? do Oeste and the Jamari National Forest area, in the period that includes the mid 50s until the late 90s of XX century. During this period cassiterite comes to occupy a prominent place in the local economy since the rubber loses its economic importance in the region and its value in the international market. The end of manual mining in 1971 attracted for the region national companies and multinational groups, which changed some aspects of mineral exploration and working relationships in order to make them more human than they were in the days of the rubber and later of the mines. With the emergence of Itapu? do Oeste in the late 70 the differences between Itapu? do Oeste and the Jacund? Mining are immense in terms of the basic structures of care for the population, such as sanitation, prevention of endemic diseases, public lighting, education, etc. But with the breakdown of cassiterite in 1989/1990 in the international market, the cassiterite mining underwent a process of adaptation to the new reality imposed by the market, so a significant part of the population of Jacund? Mining that has not been fired began to settle in the Itapu? do Oeste at a time when the district Itapu? do Oeste is elevated to municipality.
O presente trabalho ? o fruto, de pelo menos, dez anos de pesquisa desde a elabora??o do projeto, a primeira entrevista e os primeiros documentos catalogados no Centro de Documenta??o Hist?rica do Tribunal de Justi?a de Rond?nia. Trata sobre as rela??es sociais e econ?micas na ?rea do atual Munic?pio de Itapu? do Oeste e da Floresta Nacional do Jamari, no per?odo que compreende meados dos anos 50 at? o final da d?cada de 90 do s?culo XX. Nesse per?odo a cassiterita passa a ocupar lugar de destaque na economia local, j? que a borracha perde sua import?ncia econ?mica na regi?o e seu valor no mercado internacional. O fim do garimpo manual em 1971 atraiu para a regi?o empresas nacionais e grupos multinacionais, que mudaram alguns aspectos da explora??o mineral e as rela??es de trabalho, de modo a torn?-las mais humanas do que eram nos tempos dos seringais e posteriormente dos garimpos. Com o surgimento do povoado de Itapu? do Oeste no final dos anos 70 as diferen?as entre Itapu? do Oeste e a Minera??o Jacund? s?o imensas do ponto de vista das estruturas b?sicas de atendimento ? sua popula??o, tais como: saneamento b?sico, preven??o ?s doen?as end?micas, ilumina??o p?blica, educa??o, etc. Por?m, com a quebra da cassiterita entre 1989/1990, no mercado internacional, a minera??o de cassiterita viveu um processo de adapta??o ? nova realidade imposta pelo mercado, assim uma parte significativa da popula??o da Minera??o Jacund? que n?o foi demitida passou a fixar resid?ncia no distrito de Itapu? do Oeste em um momento que o distrito ? elevado ? condi??o de Munic?pio.

Aryl-substituted polycarboxylic acids and aryl-substituted phosphonocarboxylic acids (including polyphosphono/polycarboxylic acids) were synthesised using new and known techniques. These acids were prepared for evaluation as potential collectors and have been assessed by Aberfoyle Resources Pty. Ltd., for use in the flotation of cassiterite and other metal oxides. The acids represent a new structural group of collectors for use in this field. The structural chemical-physical features of the acids have been correlated with the flotation results obtained to optimise collector design. Synthesis of the aryl-substituted polycarboxylic acids was carried out via established methodology to obtain thirty seven such acids, containing from one to four carboxylic acid functionalities per molecule. Various para-substituents were included to investigate the effect of both the hydrophilic and hydrophobic entities within the compounds on collector efficiency based on grade and net recovery of cassiterite. Some of these acids, notably some of the 2-(4-substitutedphenyl) propane-1,1,3-tricarboxylic acids, had not been reported previously in the literature. The aryl-substituted phosphonocarboxylic acids prepared possessed similar structural characteristics to the acids above, with one or more of the carboxylic acid groups being replaced by phosphonic acid functionalities. Previously prepared acids of this class were, in general, poorly characterised prior to this work or not found in the literature. In this work particular use has been made of N.M.R. spectroscopy ( P31, C13, H 1) to elucidate and confirm the structure of the proposed collectors. The flotation results for the two classes of collectors have been compared and contrasted, and some structure-collector property relationships proposed. In general the new classes of collectors were found to be far superior to those collectors in current commercial use.

A heavy mineral provenance study of stanniferous placers in northeastern Tasmania reveals that the placers were formed during 'long' periods of geologic time by episodic recycling dating back at least to the Permian. With the aid of heavy mineral species demonstrably deriving from granitic and basaltic source rocks, it is possible to identify placer formation events. Deep leads such as Briseis and Pioneer were stratigraphically confined between the Middle Eocene (ca. 47 Ma) and Middle Miocene (ca. 16 Ma) episodes of basaltic volcanic activity. This is supported by both fission track dating and electron spin resonance (ESR) studies of alluvial zircons. The latter is a rapid semi—quantitative technique for the age estimation of the host rocks of zircon. In addition to deep leads comparatively shallow leads are also present filling bedrock channels or covering erosion surfaces cut across the rock basement. Because the erosion surfaces represent episodes of sufficient duration to cause heavy mineral enrichment, they are useful for the stratigraphic correlation of placer sequences. Quaternary placers are represented in the form of fluvial terrace deposits along the lower Ringarooma valley. Bedrock tin mineralization is widespread in northeastern Tasmania and it is unnecessary to explain the placers by invoking long transport distances for cassiterite. The presence of large cassiterite nuggets and composite grains in most alluvial workings is consistent with local derivation involving short transport distances. This is also supported by geochemically distinctive trace element patterns in Mount Cameron and Blue Tier cassiterites. The former are enriched in niobium, tantalum, and zirconium, but depleted in tungsten in comparison to the latter. The selective removal of light minerals by winnowing through episodic recycling is considered to have been mainly responsible for the genesis of the placers in northeastern Tasmania. Major geomorphological evolution events have been identified in the study area. During the Middle Miocene, basaltic flows along the middle Ringarooma valley caused drainage diversion. The northwesterly flowing streams of the Blue Tier which were formerly connected to a proto-Boobyalla River system were diverted eastwards by these basalts into the South Mount Cameron Basin. An outlet of this basin into the Great Mussel Roe River existed before downcutting and/or capture shifted the river course towards the Great Northern Plains to form the Ringarooma River course of today. At least from the Middle Eocene until the Middle Miocene, the catchment area of the proto-Boobyalla River extended well into the Blue Tier prior to diversion by the younger basaltic flows. A wide range of factors helps to determine the age of placer deposits. In the present study stratigraphic control of placers was achieved through an examination of heavy mineral provenance; volcanic and duricrust formation events, and sedimentologic, palaeo-oceanographic and palaeo-botanic evidence.

The economic importance of placer deposits has prompted both field and experimental research into the processes controlling their formation. Flume studies have advanced the understanding of placer formation but most have failed to adequately replicate the natural conditions under which most form. A uniform sand-sized bed has been commonly used to investigate the transport behaviour of heavy minerals with densities less than 5.2 g/cm3. Fluvial placers, however, generally occur in gravel-bed steams and it is unresolved whether the transport behaviour of low density heavy minerals approximates higher density minerals such as cassiterite (p ~ 7.0 g/cm3) or gold (p ~ 17.0 g/cm3). This study addressed these limitations by using a gravelsand bed mixture with cassiterite and magnetite (p ~ 4.9 g/cm3) as the heavy fraction to simulate conditions characteristic of Harris Creek, a placer-bearing gravel-bed stream in the interior of British Columbia. Field observations at this site showed that pavement break-up during spring flooding was necessary to mobilize gold and magnetite deposited within the sandier substrate. Li this study, a coarse surface pavement was developed over four days and then broken up by a highenergy flood for fifteen to sixty minutes. Six experimental runs were conducted under slightly different hydraulic and sedimentological conditions. During pavement development flow competence was insufficient to mobilize cassiterite. Selective entrainment of the lighter sand-sized fractions led to the concentration of cassiterite in the immediate subsurface as a lag deposit. A 6.0 cm board placed beneath the flume tailgate reduced downstream erosion rates and subsequent cassiterite concentrations were lower downstream. Magnetite, due to its lower density, was transported during pavement development but its transport rates were disproportionately less than its presence in the bed. Subsurface enrichment of magnetite occurred only in the lower reach. Frequent entrapment of mobilized magnetite grains in close contact with the bed and low downstream erosion rates were responsible for this pattern of enrichment. High-energy flooding broke up the developed pavement and mobilized the heavy fractions. Cassiterite, however, was at no time transported out of the flume and transport distances were apparently small based on results in Run 5. This was a result of its high density and fine grain size relative to the bed which created numerous opportunities for entrapment. The mobility of magnetite did not increase significantly during flooding with transport rates remaining disproportionately less than its presence in the bed. Low density fractions finer than 0.354 mm were also transported at disproportionately lower rates. These results are consistent with a process of vertical fractionation which concentrates fine sediment at the base of the mobile bed and makes the grains more prone to entrapment. This study demonstrates the importance of density, grain size, and bed roughness as factors controlling the transport behaviour and deposition of heavy minerals in gravel-bed streams.

Three models have been proposed for cassiterite (SnO2) mineralisation in magmatic–hydrothermal environments: (1) magmatic crystallisation from a granitic melt, (2) late-stage magmatic partition of Sn into a fluid or vapour phase and subsequent cassiterite deposition, and (3) hydrothermal leaching of Sn from granite and/or country rocks and subsequent deposition. The complex chemistry of the ‘tin’ granites, and the large and pervasive hydrothermal systems which can overprint and destroy primary features make understanding the processes responsible for Sn enrichment difficult. Two new analytical methods were developed. Firstly, a method for the determination of Rb–Sr and Sm–Nd isotopic compositions of magmatic and hydrothermal tourmalines, which can record the compositional evolution of magmas and their hydrothermal fluids. Secondly, cassiterite U–Pb geochronology to constrain the absolute age and duration of magmatic–hydrothermal Sn systems. These data, together with major and trace element compositions of tourmaline, whole-rock geochemistry, quartz δ18O values and zircon U–Pb geochronology are applied to two Sn deposits associated with the Ardlethan and Mole granites of eastern Australia. The geochemical and isotope data of tourmaline show large compositional changes across the magmatic–hydrothermal transition. In the Ardlethan Granite, tourmaline 87Rb–86Sr isotope compositions, which provide robust estimates of 87Sr/86Sr(i) because of their low 87Rb/86Sr, are used to model the assimilation and fractional crystallisation processes that lead to a 30-times enrichment of Sn in residual melts relative to the source rocks. However, caution must be taken with interpreting 87Sr/86Sr(i) tourmaline data as high 87Rb/86Sr of parental melts and fluids can lead to significant in-situ decay of 87Rb prior to tourmaline precipitation. This phenomon is hypothesised for the parental melts of the Mole Granite which due toextreme fractional crystallisation have extreme 87Rb/86Sr of ~900. Subsequently 87Sr/86Sr(i) tourmaline compositions are more evolved the the whole rock composition. The Sn concentration of tourmaline increases from magmatic to hydrothermal settings within the Ardlethan and Mole granites, recording the exsolution of a fluid from a silicate melt. The enrichment of Sn during fluid fractionation, recorded by tourmaline, agrees with experimentally determined melt–fluid partitioning coefficients. Fluid fractionation is the dominant enrichment process for greisen deposits of the Ardlethan Granite, and all deposits of the Mole Granite. Fluid leaching of host rocks is evidenced by convergence of Fe/(Fe+Mg), Sr, 87Sr/86Sr(i) and εNd(i) in hydrothermal tourmaline from the original source rock composition to the host rock composition. At Ardlethan, the host rock of mineralised breccia pipes is enriched in Sn (~50 ppm) and fluid leaching results in an increase of Sn in the mineralising fluids. Although fluid leaching occurs around the Mole Granite, the low Sn concentrations in the host rocks limits Sn enrichment. Melt/fluid-mineral partitioning is a major uncertainty in the interpretation of tourmaline trace element geochemistry. Natural studies performed here provide some constraints, however, more targeted experimental work is required. A new method for U–Pb characterisation of cassiterite by ID-TIMS has provided a matrix-matched reference material for in-situ techniques. However, common-Pb corrections of in-situ techniques remain a large uncertainty in cassiterite geochronology. At Ardlethan, the common-Pb compositions are appropriately estimated by terrestrial Earth models and are more precise than isochron ages. Conversely, the common-Pb associated with the Mole Granite appears variable between a terrestrial Earth composition and a highly evolved composition. Cassiterite U–Pb geochronology of both the Ardlethan and Mole granite mineralisation systems indicate precipitation synchronous with emplacement. The method does not have sufficient precision (~4 % absolute) to distinguish the age of cassiterite precipitation from that of zircon, however, the magmatic–hydrothermal systems of the Ardlethan and Mole granites persisted for a maximum of 4.2 Ma.

The Ardlethan Tin Field is located near the western edge of the Lachlan Fold Belt in New South Wales, Australia. The oldest rocks in the Ardlethan Tin Field are metasedimentary rocks of Ordovician age. They were intruded during late Silurian-early Devonian times by the Mine Granite and the Ardlethan Granite dated at 417+2.5 and 410+2.5 Ma respectively. The latter is strongly fractionated and has three daughter phases: the Garnet-Bearing Quartz Feldspar Porphyry (GQFP), the microgranite and the Mine Porphyry. The GQFP represents a marginal phase, the microgranite a moderately fractionated phase and the Mine Porphyry a late stage strongly fractionated phase. Four breccia pipes, the Mine Granite, Carpathia-Blackreef, Stackpool-Godfrey and the White Crystal Breccia Pipes were formed sequentially in three brecciation events. They are hosted by the Mine Granite. Each brecciation event was followed by hydrothermal alteration, and cassiterite and sulphide mineralization. Fluid exsolution during crystallization of the most fractionated sediment and mafic dykes in the breccia pipes indicates a complex evolutionary history during their formation. The materials in the Mine Granite, Carpathia-Blackreef and the Stackpool-Godfrey Breccia Pipes have moved upward significantly. The White Crystal Breccia Pipe is the only one which has collapsed. The mineralization in the breccia pipes was strongly controlled by permeability. The Mine Granite Breccia Pipe has an impermeable central zone of rock flour-supported breccia and a marginal zone of fragment supported breccia. Mineralization of economic grades only occurs in the marginal zone. A similar situation occurs in the upper levels of the Carpathia-Blackreef and Stackpool-Cioclfrey Breccia Pipes. The White Crystal Breccia Pipe contains no rock flour-supported breccia so that mineralization occurs mainly in the central zone. Cassiterite and sulphide mineralization in the breccia pipes is associated with hydrothermal biotite, sericite, tourmaline, quartz, topaz and chlorite. A common paragenetic sequence observed in all the breccia pipes is early cassiterite deposition with sericite, tourmaline and milky quartz, followed by sulphide deposition with clear quartz, toothy quartz, fluorite and cookeite vug infill and chlorite alteration. An independent event of cosalite mineralization, associated with native bismuth and bismuthinite, occurs in fractures and veins postdating the cassiterite and sulphide mineralization in the Blackreef-Godfrey area. The compositions of biotite, tourmaline, muscovite and chlorite in the Ardlethan Granite are enriched in FeO and depleted in MgO compared to biotite, tourmaline, muscovite and chlorite in fresh Mine Granite. Those in the alteration zones formed during rock-fluid reactions are generally of intermediate compositions. Fluid inclusion microthermometric data indicate that cassiterite and milky quartz deposition in the Ardlethan Tin Field occurred at temperatures between 360 and 31 0°C; sulphide and clear quartz between 270 and 220°C; and toothy quartz, fluorite and cookeite between 200 and 150°C. Coexistence of C02-rich and H20-rich fluid inclusions allowed a minimum pressure estimate of about 450 bars during mineralization. Temperatures calculated from the compositions of the hydrothermal biotite, muscovite and chlorite suggest that biotite alteration occurred between 420 and 360oc, sericite alteration between 330 and 290oc and chlorite alteration mainly between 290 and 1 05oC. These results are in good agreement with the fluid inclusion microthermometry and the paragenesis. The oxygen isotope compositions of milky quartz, clear quartz and toothy quartz are mostly between 11.5 and 13.5 per mil regardless of the wide temperature range of their formation. This suggests a complex evolution in the fluid during mineralization probably due to continued rock-fluid equilibria. The sulphur isotope compositions of the sulphides formed during the main stage mineralization are very close to 0 per mil and the carbon isotope values mostly 4.3+ 1.0 per mil. They either support of milky quartz, clear quartz and toothy quartz are mostly between 11.5 and 13.5 per mil regardless of the wide temperature range of their formation. This suggests a complex evolution in the fluid during mineralization probably due to continued rock-fluid equilibria. The sulphur isotope compositions of the sulphides formed during the main stage mineralization are very close to 0 per mil and the carbon isotope values mostly 4.3+ 1.0 per mil. They either support or permit a interpretation that the fluid responsible for the cassiterite and sulphide mineralization was derived from the Ardlethan Granite and continuously equilibrated with the Mine Granite. The sulphur isotope compositions of the sulphides in association with the cosalite mineralization are > 10.0 per mil and indicate that the cosalite mineralization was an independent event. Thermodynamic study of mineral-fluid equilibria suggests that there were continual changes in temperature, pH and redox conditions as the fluid flowed upwards in the breccia pipes. These changes caused various styles of hydrothcnrwl alteration and cassiterite and sulphide depositions. The brecciation and breccia pipe-hosted cassiterite and sulphide mineralization may be interpreted in terms of a dynamic process involving magma fractionation in the Ardlethan Granite, episodic brecciation, fluid flow, rock -fluid reactions, fluid boiling, alteration and mineral deposition. The process started with the fractionation in the Ardlethan Granite. Accumulated volatiles build up an over-pressure which caused brecciation and formation of the Mine Granite Breccia Pipe. At this stage the Ardlethan Granite was only partially crystallized and the brecciation was followed by the intrusion of a differentiated magma, represented by the Mine Porphyry, which moved the materials in the Mine Granite Breccia Pipe upwards. The continual crystallization in the Ardlethan Granite kept a steady supply of fluid which was channelled into the most permeable marginal zones of the breccia pipe. As the fluid flowed upwards, it cooled, reacted with minerals in the brecciated rocks and boiled. The resultant physico-chemical gradients along the fluid paths caused biotite alteration; cassiterite and milky quartz deposition with sericite and tourmaline alteration: sulphide and clear quartz deposition; toothy quartz, fluorite and ite deposition and chlorite alteration sequentially in zones from depth ro surface. Mineral deposition gradually reduced the permeability of the Mine Granite Breccia Pipe and the fluid flux, caused a slow retreat of t vertical zonations. When the Mine Granite was completely sealed by mineral deposition, fluid accumulation started again at depth and resulted in the brecciation of the Carpathia-Blackreef and the Stackpool frey Breccia Pipes. Similar processes occurred. The White Crystal Breccia Pipe represents the third brecciation event in the Ardlethan Tin Field. Its collapse reflects the depletion of volatiles and completion of crystallization of the Ardlethan Granite.

Studies of the tectonic evolution and associated ore genesis through time are fundamental to understanding Earth’s crustal growth, evolution, and related enrichment in metal deposits. The present PhD research work has focused on the tin (Sn) ore genesis and tectonic evolution of the Karagwe–Ankole Belt (KAB), with a case study area of Rwanda, east-central Africa. This work addresses the controversial geodynamic evolution of the KAB and puts mineralisation in a tectonic context which has been debatable. This thesis work has discovered Archean crust in the Rusizian terrane of the Western Domain of KAB, SW Rwanda, where the basement was previously thought to be Paleoproterozoic. The discovery of the reported Neoarchean basement provides new insight into the tectonic setting of the KAB by defining the reworked north-western margin of the Tanzania Craton. This thesis also presents evidence for high-pressure granulite facies metamorphism in the Western Domain of the KAB, providing new insight into the tectonic evolution of the orogenic belt during the amalgamation of Rodinia. The present thesis provides constraints from petrology, geochemistry and geochronology on the granitic rocks from Rwanda, further indicating a collisional or convergent setting for the Mesoproterozoic evolution of the KAB. In the present work, detailed ore geology and micro-textural characterisation of cassiterite, representing major mineralisation in the KAB, have been carried out to understand the mechanism of tin ore formation and cassiterite chemistry. With simple modifications, the sensitivity of the SIMS U-Pb technique was improved, and a meaningful precision was achieved in the dating of hydrothermal cassiterite with sub-ppm U contents. This thesis reports the first SHRIMP direct U-Pb dating of cassiterite mineralisation in the KAB, Rwanda, and through the zircon and monazite dating of igneous rocks that are potentially linked to the mineralisation, places the several styles and episodes of mineralisation in a tectonic context. It also shows the value of monazite in dating felsic/fractionated igneous rocks in which the zircon has suffered major radiation damage. The links demonstrated between mineralisation, magmatism, geological setting and tectonism not only help to clarify the mineralisation process, but also will assist in targeting exploration for further tin deposits in both Rwanda and neighbouring countries. Furthermore, this thesis newly addresses xanthan gum-based investigations into the surface chemistry of cassiterite and beneficiation of cassiterite tailings, contributing to a new development for the recovery of a good grade of the cassiterite lost in gravity tailings from the world class tin deposits of the KAB, Rwanda