THEREDA (Thermodynamic Reference Database) is a collaborative project, which has been addressed this challenge. The partners are Helmholtz-Zentrum Dresden-Rossendorf, Karlsruhe Institute of Technology (KIT-INE), Gesellschaft für Anlagen- und Reaktorsicherheit Braunschweig mbH (GRS), TU Bergakademie Freiberg (TUBAF) and AF-Consult Switzerland AG (Baden, Switzerland). The aim of the project is the establishment of a consistent and quality assured database for all safety relevant elements, temperature and pressure ranges, with its focus on saline systems. This implied the use of the Pitzer approach to compute activity coefficients suitable for such conditions. Data access is possible via commonly available internet browsers under the address http://www.thereda.de. One part of the project - the data collection and evaluation for uranium – was a task of the Helmholtz-Zentrum Dresden-Rossendorf. The aquatic chemistry and thermodynamics of U(VI) and U(IV) is of great importance for geochemical modelling in repository-relevant systems. The OECD/NEA Thermochemical Database (NEA TDB) compilation is the major source for thermodynamic data of the aqueous and solid uranium species, even though this data selection does not utilize the Pitzer model for the ionic strength effect correction. As a result of the very stringent quality demands, the NEA TDB is rather restrictive and therefore incomplete for extensive modelling calculations of real systems. Therefore, the THEREDA compilation includes additional thermodynamic data of solid secondary phases formed in the waste material, the backfill and the host rock, though falling into quality assessment (QA) categories of lower accuracy. The data review process prefers log K values from solubility experiments (if available) to those calculated from thermochemical data.

Thesis (doctoral)--Utrecht University, the Netherlands, 2005. / Includes bibliographical references (p. 175-183).

THEREDA (Thermodynamic Reference Database) is a collaborative project, which has been addressed this challenge. The partners are Helmholtz-Zentrum Dresden-Rossendorf, Karlsruhe Institute of Technology (KIT-INE), Gesellschaft für Anlagen- und Reaktorsicherheit Braunschweig mbH (GRS), TU Bergakademie Freiberg (TUBAF) and AF-Consult Switzerland AG (Baden, Switzerland). The aim of the project is the establishment of a consistent and quality assured database for all safety relevant elements, temperature and pressure ranges, with its focus on saline systems. This implied the use of the Pitzer approach to compute activity coefficients suitable for such conditions. Data access is possible via commonly available internet browsers under the address http://www.thereda.de. One part of the project - the data collection and evaluation for uranium – was a task of the Helmholtz-Zentrum Dresden-Rossendorf. The aquatic chemistry and thermodynamics of U(VI) and U(IV) is of great importance for geochemical modelling in repository-relevant systems. The OECD/NEA Thermochemical Database (NEA TDB) compilation is the major source for thermodynamic data of the aqueous and solid uranium species, even though this data selection does not utilize the Pitzer model for the ionic strength effect correction. As a result of the very stringent quality demands, the NEA TDB is rather restrictive and therefore incomplete for extensive modelling calculations of real systems. Therefore, the THEREDA compilation includes additional thermodynamic data of solid secondary phases formed in the waste material, the backfill and the host rock, though falling into quality assessment (QA) categories of lower accuracy. The data review process prefers log K values from solubility experiments (if available) to those calculated from thermochemical data.

Die geochemischen Verhältnisse der Böden des Erzgebirge und Vogtlandes werden auf der Grundlage der komplexen geochemischen Analyse von ausgewählten, flächenrepräsentativen Bodenprofilen auf Hauptgesteinen des Untersuchungegebietes charakterisiert. Die Wirkungsweisen vorhandener Einflussfaktoren (Gesteinschemismus, Bodengenese, Bodennutzung) werden untersucht und bewertet. Die Untersuchungen stellen eine Grundlage für die Ableitung von geologisch bedingten regionalen Hintergrundbelastungen dar. / A characterization of the soil geochemistry of the Erzgebirge and Vogtland Regions (Saxony) is provided on the basis of the investigation of characteristic soil profiles on major bedrock types of the area. Different factors of influence (rock geochemistry, soil formation, land utilization) are investigated and evaluated. The investigation provides essential information for the development of regional background concentrations.

In bergmännisch geschaffenen Hohlräumen in Sulfiderzlagerstätten findet durch den Kontakt sauerstoffhaltiger Wässer mit den künstlich vergrößerten Reaktionsoberflächen resterzhaltigen Materials eine permanente, intensive Sulfidoxidation statt, die zu einer hohen Löslichkeit von Elementen führt. Beispielhaft wurde die polysulfidische Gangerz-Lagerstätte Freiberg untersucht. Geochemische Bedeutung besitzen hier die Elemente Cd, Cu, Fe, Mn, Ni, Pb, Zn, Al und As. An wichtigen primären Mineralen wurde die Elementfreisetzung untersucht. Die Auswirkung der Elementmobilisation auf die Grundwasserqualität wurde verfolgt. Dabei konnte auf Besonderheiten der Grubenwässer stillgelegter Abbaue, der Stollnwässer und des Flutungswassers eingegangen werden. Die Aufnahme der Stofffrachten führt ebenso wie ihre selektive, partielle Präzipitation zu typischen, sulfatischen Grubenwässern. Die Fällungssedimente wurden mineralogisch und geochemisch charakterisiert. Die stillgelegte Sulfiderzgrube wurde als Quelle und Senke für direkt oder indirekt umweltrelevante Elemente beschrieben, deren im Wasser transportierte Stofffrachten insbesondere für Cd, Pb und As ökotoxikologisch von Bedeutung sind.

In bergmännisch geschaffenen Hohlräumen in Sulfiderzlagerstätten findet durch den Kontakt sauerstoffhaltiger Wässer mit den künstlich vergrößerten Reaktionsoberflächen resterzhaltigen Materials eine permanente, intensive Sulfidoxidation statt, die zu einer hohen Löslichkeit von Elementen führt. Beispielhaft wurde die polysulfidische Gangerz-Lagerstätte Freiberg untersucht. Geochemische Bedeutung besitzen hier die Elemente Cd, Cu, Fe, Mn, Ni, Pb, Zn, Al und As. An wichtigen primären Mineralen wurde die Elementfreisetzung untersucht. Die Auswirkung der Elementmobilisation auf die Grundwasserqualität wurde verfolgt. Dabei konnte auf Besonderheiten der Grubenwässer stillgelegter Abbaue, der Stollnwässer und des Flutungswassers eingegangen werden. Die Aufnahme der Stofffrachten führt ebenso wie ihre selektive, partielle Präzipitation zu typischen, sulfatischen Grubenwässern. Die Fällungssedimente wurden mineralogisch und geochemisch charakterisiert. Die stillgelegte Sulfiderzgrube wurde als Quelle und Senke für direkt oder indirekt umweltrelevante Elemente beschrieben, deren im Wasser transportierte Stofffrachten insbesondere für Cd, Pb und As ökotoxikologisch von Bedeutung sind.

Tailings are the fine-grained residues produced by processing operations, and are commonly retain residual contents of valuable and critical metals. Re-mining of tailings storage facilities (TSF) could play a crucial role in alleviating environmental problems associated with mine wastes, while recovering residual value and decreasing the volumes of tailings to be stored. Resource modelling of TSFs is complicated by their heterogeneity, which results from the sedimentary-style deposition of tailings, as well as post-depositional processes like weathering. Tailings particles are sorted based on size and density (i.e., mineralogy), generating strong systematic trends in geochemistry across a TSF. As such, TSFs should not be treated the same way as primary deposits; different sampling, spatial modelling, and processing methods may be needed, as well as adaptions to resource and reserve reporting codes. This thesis provides recommendations for the resource and reserve estimation of TSFs. To achieve this, a series of methods were developed, from best-practise sampling of TSFs for resource estimation, through to geostatistical modelling of a TSF for grade/tonnage estimation with corresponding uncertainties, to geometallurgical modelling using particle-based data.

Die hyperspektrale Bildgebung stellt eine Schlüsseltechnologie in der nicht-invasiven Mineralanalyse dar, sei es im Labormaßstab oder als fernerkundliche Methode. Rasante Entwicklungen im Sensordesign und in der Computertechnik hinsichtlich Miniaturisierung, Bildauflösung und Datenqualität ermöglichen neue Einsatzgebiete in der Erkundung mineralischer Rohstoffe, wie die drohnen-gestützte Datenaufnahme oder digitale Aufschluss- und Bohrkernkartierung. Allgemeingültige Datenverarbeitungsroutinen fehlen jedoch meist und erschweren die Etablierung dieser vielversprechenden Ansätze. Besondere Herausforderungen bestehen hinsichtlich notwendiger radiometrischer und geometrischer Datenkorrekturen, der räumlichen Georeferenzierung sowie der Integration mit anderen Datenquellen. Die vorliegende Arbeit beschreibt innovative Arbeitsabläufe zur Lösung dieser Problemstellungen und demonstriert die Wichtigkeit der einzelnen Schritte. Sie zeigt das Potenzial entsprechend prozessierter spektraler Bilddaten für komplexe Aufgaben in Mineralexploration und Geowissenschaften. / Hyperspectral imaging (HSI) is one of the key technologies in current non-invasive material analysis. Recent developments in sensor design and computer technology allow the acquisition and processing of high spectral and spatial resolution datasets. In contrast to active spectroscopic approaches such as X-ray fluorescence or laser-induced breakdown spectroscopy, passive hyperspectral reflectance measurements in the visible and infrared parts of the electromagnetic spectrum are considered rapid, non-destructive, and safe. Compared to true color or multi-spectral imagery, a much larger range and even small compositional changes of substances can be differentiated and analyzed. Applications of hyperspectral reflectance imaging can be found in a wide range of scientific and industrial fields, especially when physically inaccessible or sensitive samples and processes need to be analyzed. In geosciences, this method offers a possibility to obtain spatially continuous compositional information of samples, outcrops, or regions that might be otherwise inaccessible or too large, dangerous, or environmentally valuable for a traditional exploration at reasonable expenditure. Depending on the spectral range and resolution of the deployed sensor, HSI can provide information about the distribution of rock-forming and alteration minerals, specific chemical compounds and ions. Traditional operational applications comprise space-, airborne, and lab-scale measurements with a usually (near-)nadir viewing angle. The diversity of available sensors, in particular the ongoing miniaturization, enables their usage from a wide range of distances and viewing angles on a large variety of platforms. Many recent approaches focus on the application of hyperspectral sensors in an intermediate to close sensor-target distance (one to several hundred meters) between airborne and lab-scale, usually implying exceptional acquisition parameters. These comprise unusual viewing angles as for the imaging of vertical targets, specific geometric and radiometric distortions associated with the deployment of small moving platforms such as unmanned aerial systems (UAS), or extreme size and complexity of data created by large imaging campaigns. Accurate geometric and radiometric data corrections using established methods is often not possible. Another important challenge results from the overall variety of spatial scales, sensors, and viewing angles, which often impedes a combined interpretation of datasets, such as in a 2D geographic information system (GIS). Recent studies mostly referred to work with at least partly uncorrected data that is not able to set the results in a meaningful spatial context. These major unsolved challenges of hyperspectral imaging in mineral exploration initiated the motivation for this work. The core aim is the development of tools that bridge data acquisition and interpretation, by providing full image processing workflows from the acquisition of raw data in the field or lab, to fully corrected, validated and spatially registered at-target reflectance datasets, which are valuable for subsequent spectral analysis, image classification, or fusion in different operational environments at multiple scales. I focus on promising emerging HSI approaches, i.e.: (1) the use of lightweight UAS platforms, (2) mapping of inaccessible vertical outcrops, sometimes at up to several kilometers distance, (3) multi-sensor integration for versatile sample analysis in the near-field or lab-scale, and (4) the combination of reflectance HSI with other spectroscopic methods such as photoluminescence (PL) spectroscopy for the characterization of valuable elements in low-grade ores. In each topic, the state of the art is analyzed, tailored workflows are developed to meet key challenges and the potential of the resulting dataset is showcased on prominent mineral exploration related examples. Combined in a Python toolbox, the developed workflows aim to be versatile in regard to utilized sensors and desired applications.

Die geochemischen Verhältnisse der Böden des Erzgebirge und Vogtlandes werden auf der Grundlage der komplexen geochemischen Analyse von ausgewählten, flächenrepräsentativen Bodenprofilen auf Hauptgesteinen des Untersuchungegebietes charakterisiert. Die Wirkungsweisen vorhandener Einflussfaktoren (Gesteinschemismus, Bodengenese, Bodennutzung) werden untersucht und bewertet. Die Untersuchungen stellen eine Grundlage für die Ableitung von geologisch bedingten regionalen Hintergrundbelastungen dar. / A characterization of the soil geochemistry of the Erzgebirge and Vogtland Regions (Saxony) is provided on the basis of the investigation of characteristic soil profiles on major bedrock types of the area. Different factors of influence (rock geochemistry, soil formation, land utilization) are investigated and evaluated. The investigation provides essential information for the development of regional background concentrations.

The general temperature range for THEREDA is currently limited to 0 to about 110°C. For the important electrolyte NaCl there are thermodynamic data available to 200°C and above. To cover this larger temperature range for the Pitzer coefficients, a refit of the temperature functions of Greenberg, J. P. and Møller, N. (Geochim. Cosmochim. Acta 53 (1989) 2503-2518) is presented. A corresponding function for the solubility constant of NaCl is deduced from IUPAC recommended data. The data set for NaCl, thus extended in its range of validity up to 200°C, is implemented in THEREDA.