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Investigation of depleted uranium migration offsite from a military ordnance range : potential concentrations and radiological dosesRynders, David G. 10 January 1997 (has links)
Graduation date: 1997
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Migration and gamma ray assessment of uranium on a gold tailings disposal facility / Jaco KochKoch, Jaco January 2014 (has links)
This project aims to quantify natural gamma radiation in gold tailings disposal facilities (TDFs)
relative to uranium concentration data in order to use natural gamma detection methods as
alternative methods for uranium resource estimation modelling in gold tailings. Uranium
migration within the New Machavie TDF was also investigated as migration affects both the
grade of the TDF as a uranium resource and poses a threat to the environment. In order to
determine the most appropriate radiometric testing procedure, various methods were employed
for natural gamma detection, including surface natural gamma spectrometry, borehole natural
gamma spectrometry and scintillometry, as well as incremental sampling. These measurements
were then statistically compared to ICP-MS analyses to find the best method, and then
modelled to apply volumetric resource estimation procedures. The oxidation reduction potential
was also tested as uranium geochemistry is dependent on oxidation for mobilisation.
Furthermore, leaching tests were employed to relate specific anions as a mode of transportation
in solution. Results indicated that down-hole natural gamma spectrometry performed the best
and that 2376.87 kg of uranium is present in the TDF. Migration modelling indicated that
uranium is mobilised away from the oxidized top area of the TDF and that accumulation occurs
in the saturated zone of the TDF under a reducing environment. Sulphate anions as the result of
pyrite oxidation are primarily responsible for the mobilisation as radionuclides in New Machavie.
The results of this project can be applied to the resource estimation of all uranium bearing
tailings facilities prior to re-mining as a means to decrease exploration costs and to accurately
model the distribution of uranium. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014
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Migration and gamma ray assessment of uranium on a gold tailings disposal facility / Jaco KochKoch, Jaco January 2014 (has links)
This project aims to quantify natural gamma radiation in gold tailings disposal facilities (TDFs)
relative to uranium concentration data in order to use natural gamma detection methods as
alternative methods for uranium resource estimation modelling in gold tailings. Uranium
migration within the New Machavie TDF was also investigated as migration affects both the
grade of the TDF as a uranium resource and poses a threat to the environment. In order to
determine the most appropriate radiometric testing procedure, various methods were employed
for natural gamma detection, including surface natural gamma spectrometry, borehole natural
gamma spectrometry and scintillometry, as well as incremental sampling. These measurements
were then statistically compared to ICP-MS analyses to find the best method, and then
modelled to apply volumetric resource estimation procedures. The oxidation reduction potential
was also tested as uranium geochemistry is dependent on oxidation for mobilisation.
Furthermore, leaching tests were employed to relate specific anions as a mode of transportation
in solution. Results indicated that down-hole natural gamma spectrometry performed the best
and that 2376.87 kg of uranium is present in the TDF. Migration modelling indicated that
uranium is mobilised away from the oxidized top area of the TDF and that accumulation occurs
in the saturated zone of the TDF under a reducing environment. Sulphate anions as the result of
pyrite oxidation are primarily responsible for the mobilisation as radionuclides in New Machavie.
The results of this project can be applied to the resource estimation of all uranium bearing
tailings facilities prior to re-mining as a means to decrease exploration costs and to accurately
model the distribution of uranium. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014
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Influence of Humic Acids on the Migration Behavior of Radioactive and Non-Radioactive Substances Under Conditions Close to Nature -Synthesis, Radiometric Determination of Functional Groups, Complexation-: Influence of Humic Acids on the Migration Behavior of Radioactive and Non-Radioactive Substances Under Conditions Close to Nature -Synthesis, Radiometric Determination of Functional Groups, Complexation-Nitsche, Heino, Heise, Karl-Heinz, Bernhard, Gert, Schmeide, Katja, Pompe, Susanne, Bubner, Marianne January 2000 (has links)
The interaction behavior of humic acids with uranium(VI) and the influence of humic substances on the migration behavior of uranium was investigated. A main focus of this work was the synthesis of four different humic acid model substances and their characterization and comparison to the natural humic acid from Aldrich. A radiometric method for the determination of humic acid functional groups was applied in addition to conventional methods for the determination of the functionality of humic acids. The humic acid model substances show functional and structural properties comparable to natural humic acids. Modified humic acids with blocked phenolic OH were synthesized to determine the influence of phenolic OH groups on the complexation behavior of humic acids. A synthesis method for 14C-labeled humic acids with high specific activity was developed. The complexation behavior of synthetic and natural humic acids with uranium(VI) was investigated by X-ray absorption spectroscopy, laser-induced fluorescence spectroscopy and FTIR spectroscopy. The synthetic model substances show an interaction behavior with uranium(VI) that is comparable to natural humic acids. This points to the fact that the synthetic humic acids simulate the functionality of their natural analogues very well. For the first time the influence of phenolic OH groups on the complexation behavior of humic acids was investigated by applying a modified humic acid with blocked phenolic OH groups. The formation of a uranyl hydroxy humate complex was identified by laserspectroscopic investigations of the complexation of Aldrich humic acid with uranium(VI)at pH 7. The migration behavior of uranium in a sandy aquifer system rich in humic substances was investigated in column experiments. A part of uranium migrates non-retarded through the sediment, bound to humic colloids. The uranium migration behavior is strongly influenced by the kinetically controlled interaction processes of uranium with the humic colloids. The influence of humic acids on the sorption of uranium(VI) onto phyllite was investigated in batch experiments using two different humic acids. The uranium(VI) sorption onto the rock phyllite is influenced by the pH-dependent sorption behavior of the humic acids.
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