O conhecido histórico de contaminação por passivos da mineração de galena (PbS) da região do Vale do Ribeira (SP) faz com que seja de grande importância o estudo da adsorção de Pb com a finalidade de determinar a capacidade de sorção de materiais inconsolidados do município de Eldorado Paulista (SP) para serem empregados como barreira selante na contenção da lixiviação de metais por resíduos de mineração (com destaque para o Pb). O objetivo do presente trabalho foi avaliar a adsorção de Pb por meio de ensaios de equilíbrio em lote. Para realizar tal objetivo, foram coletadas 4 amostras de materiais inconsolidados (3 transportados e 1 residual) no município de Eldorado Paulista, anteriormente caracterizadas. Foram realizados ensaios de caracterização dos materiais (MO, \'delta\'pH, compactação e permeabilidade) visando determinar as principais características que influenciam na retenção de metais, assim como ensaios de equilíbrio em lote para avaliar a capacidade de adsorção de Pb. O ensaio BET foi realizado com amostras triplicatas dos 4 solos, empregando concentrações iniciais de Pb aproximadas de 30, 60, 90 e 120 mg L-1, massa de solo de 20 g, tempo de contato de 24 horas e razão massa/solução de 1/5. Com os resultados obtidos foram confeccionadas isotermas de sorção segundo os modelos Linear, de Freundlich e Langmuir I e II. Os resultados indicaram que os materiais inconsolidados transportados T2 e T3 são os mais adequados para o emprego em barreira selante para contenção de Pb, sendo suas capacidades de adsorção influenciadas, principalmente, pelo teor de óxidos de ferro e fração argila. As melhores sorções foram obtidas para os solos T2 e T3 para concentrações iniciais aproximadas entre 30 e 120 mg L-1. Desta forma, conclui-se que o ensaio BET foi adequado para determinação da adsorção por metais. / The known history of contamination by galena (PbS) mining liabilities from Ribeira Valley region (SP) provides importance to the Pb adsorption study in order to determine the sorption by unconsolidated materials from Eldorado Paulista city (SP) to be employed as liners to contain metals leaching derived from mining (with emphasis on Pb). The objective of the current work was assess the Pb adsorption by Batch Equilibrium Tests. To accomplish this objective, 4 unconsolidated materials samples were collected in Eldorado Paulista, previously characterized. Characterization tests were performed (MO, \'delta\'pH, compaction and permeability) to determine the main characteristics that influence the retention of metals, and Batch Equilibrium Tests to assess soils capacities of Pb adsorption. BET was performed with triplicate samples of the 4 materials, applying initial Pb concentrations around 30, 60, 90 and 120 mg L-1, mass of soil about 20 g, mass/solution rate of 1/5 and 24 hours of contact time. the results provide sorption isotherms modeled by Linear, Freundlich and Langmuir I and II equations. The results indicated that unconsolidated materials T2 and T3 are the best suited for use in liners to retain Pb, and their sorption capacities are mainly influenced by iron oxides content and clay content. Best sorption were obtained to soils T2 and T3 with initial concentrations about 30 to 120 mg L-1. Thus, it is concluded that BET is appropriated to determine metals adsorption.

[pt] Nas operações de testemunhagem o acunhamento é uma preocupação permanente. Denomina-se acunhamento quando a amostra de rocha não prossegue adentrando no barrilete de testemunhagem devido à fricção entre a rocha e superfície interna do barrilete. Em formações resistentes é indesejável por causar perda de tempo e prejuízo econômico, principalmente caso ocorra logo no início da corrida. Em formações inconsolidadas o prejuízo vai além, pois pode causar a perda da rocha a ser testemunhada, uma vez que a baixa resistência compressiva causa o colapso da rocha. Sendo em muitos casos não detectado na superfície, a operação não é interrompida e o trecho seguinte da rocha-reservatório passa a ser destruído. Uma previsão do comprimento a ser testemunhado até que esse evento ocorra pode ser uma maneira importante de minimizar a destruição de rocha, maximizando sua recuperação, sem o ônus de ser conservador demais. Este trabalho descreve os passos e resultados de se estabelecer um modelo para prever o acunhamento em formações inconsolidadas. Esses passos incluem: experimentos para determinar o coeficiente de fricção entre a areia e os tubos de alumínio, modelagem analítica e análise por elementos finitos para a avaliação dos resultados dos experimentos e para estabelecer o modelo de previsão. / [en] In coring operations core jamming is a permanent concern. It takes place when the core sample becomes stuck within the inner core barrel, preventing further acquisition. In hard formations it is undesirable because it stops bit penetration, and results in loss of time and money, especially if it occurs at the beginning of the core run. In unconsolidated formations the damage goes further, as the jam may become solidary to the coring bit and wash the formation away instead of acquiring it. This phenomenon is unnoticeable at surface and thus gives the operators no indicative of a premature pull out of hole need. The reservoir rock characterization will be permanently incomplete due to the unrecovered washed away material. Hence, a good prediction of a safe maximum coring length could be an important way to avoid washing the sample, maximizing recovery, without risking to be too conservative. This work describes the steps and results of establishing a model to predict jamming in unconsolidated formations. These steps includes: experiments to determine friction factor between sand and the aluminum tubes, analytical modeling, and FEM analysis to evaluate the experiment results and to establish the prediction model.

Das Ziel der vorliegenden Arbeit war die Erstellung eines dreidimensionalen Untergrundmodells der Region Göttingen basierend auf einer geotechnischen Klassifikation der unkosolidierten Sedimente. Die untersuchten Materialen reichen von Lockersedimenten bis hin zu Festgesteinen, werden jedoch in der vorliegenden Arbeit als Boden, Bodenklassen bzw. Bodenkategorien bezeichnet. Diese Studie evaluiert verschiedene Möglichkeiten durch geostatistische Methoden und Simulationen heterogene Untergründe zu erfassen. Derartige Modellierungen stellen ein fundamentales Hilfswerkzeug u.a. in der Geotechnik, im Bergbau, der Ölprospektion sowie in der Hydrogeologie dar. Eine detaillierte Modellierung der benötigten kontinuierlichen Parameter wie z. B. der Porosität, der Permeabilität oder hydraulischen Leitfähigkeit des Untergrundes setzt eine exakte Bestimmung der Grenzen von Fazies- und Bodenkategorien voraus. Der Fokus dieser Arbeit liegt auf der dreidimensionalen Modellierung von Lockergesteinen und deren Klassifikation basierend auf entsprechend geostatistisch ermittelten Kennwerten. Als Methoden wurden konventionelle, pixelbasierende sowie übergangswahrscheinlichkeitsbasierende Markov-Ketten Modelle verwendet. Nach einer generellen statistischen Auswertung der Parameter wird das Vorhandensein bzw. Fehlen einer Bodenkategorie entlang der Bohrlöcher durch Indikatorparameter beschrieben. Der Indikator einer Kategorie eines Probepunkts ist eins wenn die Kategorie vorhanden ist bzw. null wenn sie nicht vorhanden ist. Zwischenstadien können ebenfalls definiert werden. Beispielsweise wird ein Wert von 0.5 definiert falls zwei Kategorien vorhanden sind, der genauen Anteil jedoch nicht näher bekannt ist. Um die stationären Eigenschaften der Indikatorvariablen zu verbessern, werden die initialen Koordinaten in ein neues System, proportional zur Ober- bzw. Unterseite der entsprechenden Modellschicht, transformiert. Im neuen Koordinatenraum werden die entsprechenden Indikatorvariogramme für jede Kategorie für verschiedene Raumrichtungen berechnet. Semi-Variogramme werden in dieser Arbeit, zur besseren Übersicht, ebenfalls als Variogramme bezeichnet. IV Durch ein Indikatorkriging wird die Wahrscheinlichkeit jeder Kategorie an einem Modellknoten berechnet. Basierend auf den berechneten Wahrscheinlichkeiten für die Existenz einer Modellkategorie im vorherigen Schritt wird die wahrscheinlichste Kategorie dem Knoten zugeordnet. Die verwendeten Indikator-Variogramm Modelle und Indikatorkriging Parameter wurden validiert und optimiert. Die Reduktion der Modellknoten und die Auswirkung auf die Präzision des Modells wurden ebenfalls untersucht. Um kleinskalige Variationen der Kategorien auflösen zu können, wurden die entwickelten Methoden angewendet und verglichen. Als Simulationsmethoden wurden "Sequential Indicator Simulation" (SISIM) und der "Transition Probability Markov Chain" (TP/MC) verwendet. Die durchgeführten Studien zeigen, dass die TP/MC Methode generell gute Ergebnisse liefert, insbesondere im Vergleich zur SISIM Methode. Vergleichend werden alternative Methoden für ähnlichen Fragestellungen evaluiert und deren Ineffizienz aufgezeigt. Eine Verbesserung der TP/MC Methoden wird ebenfalls beschrieben und mit Ergebnissen belegt, sowie weitere Vorschläge zur Modifikation der Methoden gegeben. Basierend auf den Ergebnissen wird zur Anwendung der Methode für ähnliche Fragestellungen geraten. Hierfür werden Simulationsauswahl, Tests und Bewertungsysteme vorgeschlagen sowie weitere Studienschwerpunkte beleuchtet. Eine computergestützte Nutzung des Verfahrens, die alle Simulationsschritte umfasst, könnte zukünftig entwickelt werden um die Effizienz zu erhöhen. Die Ergebnisse dieser Studie und nachfolgende Untersuchungen könnten für eine Vielzahl von Fragestellungen im Bergbau, der Erdölindustrie, Geotechnik und Hydrogeologie von Bedeutung sein.

The Pimpama estuarine plain in subtropical southeast Queensland is comprised of Quaternary sediments infilling older bedrock. These multilayered unconsolidated sediments have various depositional origins, and are highly heterogeneous. The plain is low-lying and the surface drainage is controlled by flood mitigation measures including tidal gates and channelised streams. The control of surface drainage potentially affects the shallow water table. This modification of hydrology has implications for future viability of agriculture and also the environmental health of waterways. Increased landscape modification and water management is likely in the coming years. The combination of sediment heterogeneity, low hydraulic gradients, and artificial drainage modification result in the plain being hydrogeologically complex. In order to understand hydrologic processes in this setting, a multi-disciplinary research programme was conducted which included a drilling program, overland electromagnetic induction and other geophysical surveys (downhole gamma log, electromagnetic induction and magnetic susceptibility) to initially establish the geologic framework. These surveys were followed by hydrogeochemical testing which includes for major and minor ions and also stable isotopes, and mineralogical analysis of drillhole material. Underlying basement rock occurs at up to 60 m depth. Unconsolidated gravel and sand deposits occur within incised paleo-valleys and are overlain by predominantly low-permeability fluvial sandy clays and estuarine and lagoonal muds. Fine-grained delta sands occur in the top 15 m of the sub-surface. Within the unconsolidated sediments, hydrodynamic trends clearly discriminated between upper unconfined and lower semi-confined aquifer systems. A comparison of surface water and shallow groundwater levels indicate limited interaction of groundwater and surface water. Hydrogeochemical analysis effectively distinguished between groundwater bodies, and also distinguished saline groundwater from seawater. Trends in major ion chemistry in the semi-confined system (particularly Na/Cl and Ca/Cl ratios) showed ion exchange accompanying saline intrusion. However, due to factors such as mineral dissolution, major ion chemistry does not clearly identify solute flux trends in the shallow aquifer system. Water stable isotope analysis (δ18O and δ2H) indicated the provenance of fresh and saline groundwater and also the relative importance of the principal hydrologic processes, i.e. evaporation and water uptake by plants. Groundwater exhibited a wide range in salinity, from very fresh to hypersaline. The formation of hypersaline groundwater was attributed largely to uptake of water by mangrove forests. Since mangrove forests were more extensive at the time of the Holocene maximum sea level (approximately 6,000 years ago) than at present, some of this groundwater may represent relict salinity from this earlier time. The relationship of relict salinity to low permeability sediments, particularly at intermediate depths, and their depositional history was examined. Vertical salinity gradients and hydrogeochemistry within these sediments varied according to position within the plain, suggesting deposition under various hydrological and sea level regimes. A preliminary investigation using analysis of stable sulfate isotopes (δ34S and δ18OSO4) was made. This study shows substantial potential for the application of this technique for quantification of solute flux and sulfur chemical transformations within settings such as this coastal plain. To establish shallow groundwater flow processes, a MODFLOW-based numerical model was used to inversely estimate aquifer parameters under various recharge scenarios. The model was designed to examine the relative importance of evapotranspiration and discharge to surface waters. However, largely due to the complexity of the drainage network and non-uniform surface water flows, the quantification of surface water- groundwater interaction by consideration of hydrodynamics is problematic. Therefore, the chemistry of groundwater and surface water was compared. While the estimated contribution of rainfall to groundwater level fluctuations was significant (46%), high evapotranspiration rates reduced net recharge and it was concluded that baseflow to drains and creeks during dry periods was insignificant, and groundwater velocities in the shallow aquifer are low. The study illustrates the value of both hydrodynamic and hydrogeochemical analyses in estuarine settings where relict salinity and groundwater-aquifer interactions impact significantly on water quality. Saline groundwater is chemically distinct from theoretical mixtures of seawater and freshwater. The study also demonstrates the value of particular chemical parameters, e.g. Na/Cl and SO4/Cl ratios and stable water isotopes, for identifying hydrologic processes in this setting.