[No abstract submitted] / Science, Faculty of / Chemistry, Department of / Graduate

Lead isotope compositions of galena from the Fox Creek Fault at Manitouwadge, Ontario form an anomalous linear array of values on a standard ²⁰⁷Pb/²⁰⁴Pb vs. ²⁰⁶Pb/²⁰⁴Pb plot and a ²⁰⁸Pb/²⁰⁴Pb vs. ²⁰⁶Pb/²⁰⁴Pb plot. The last geologically reasonable time for galena mineralization along the Fox Creek Fault is during the Keweenawan age, 1100 million years ago. Using the slope of the anomalous lead line and this time of 1100 million years as the time of final galena mineralization along the fault gives an age of 2000 million years as the maximum time of emplacement of uranium parent of the anomalous leads into the crust. The corresponding Th/U ratio for the source of the anomalous leads is 5.3. Lead isotope compositions of galena from the main ore zone at Manitouwadge are extremely homogeneous and do not show a lineation, other than along a ²⁰⁴Pb error line, which would indicate them as anomalous leads. It is improbable for the ore zone deposits to be as young as 2700 million years as required by Tilton and Steiger (1969). In order to relate ore zone leads to Fox Creek Fault leads at least a three stage lead growth model is required. Possibly no genetic relation exists between ore zone and Fox Creek Fault galenas analysed to date. Single galena crystal lead isotope variations should be studied in detail within the Fox Creek Fault itself. Sulphur isotope studies may help to determine the relation between ore zone and fault zone galena at Manitouwadge. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Thesis (PhD) -- University of South Australia, 1999

Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1912. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed March 17, 2009) Includes bibliographical references.

Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1909. / Paging in original text incorrect. Numbering jumps from leaf 9 to leaf 11. Year the degrees were granted determined from "1874-1999 MSM-UMR Alumni Directory." The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed Apr. 22, 2009).

Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1910. / Degrees of Bachelor of Science in Mining Engineering determined from "1874-1999 MSM-UMR Alumni Directory". The entire thesis text is included in file. Typescript. Illustrated by authors. Title from title screen of thesis/dissertation PDF file (viewed March 13, 2009) Includes bibliographical references.

Thesis--Institut scientifique chérifien, Rabat, Morocco. / Bibliography: p. 101-102.

To complement the data, on the aqueous oxidation of sulphide minerals, that is, treatment of sulphides in aqueous solution at elevated temperatures under oxygen pressure, a study was undertaken of the aqueous oxidation of galena in sodium hydroxide solution. It was hoped by the study of the kinetics of the reaction to learn something of the mechanism involved. The reaction was followed by means of a cathoderay polarograph. A crystal of galena was mounted in a small autoclave equipped with suitable electrodes, and during the course of the reaction photographs were taken at intervals of the current-voltage curves. From the height of the lead wave relative concentrations could be recorded, and after a suitable time the run was stopped and the solution assayed to give absolute values to the wave heights. The variables of oxygen partial pressure agitation, sodium hydroxide concentration, temperature, silicate-ion, and electrical potential were investigated. It was found that the polarograph under these conditions gave reproducible results. On the basis of the experimental results three alternative mechanisms for the reaction were proposed. One of these was too indefinite to treat quantitatively, but the other two were examined by calculations using the theory of absolute reaction rates. One was found to give agreement in rate with experiment, a model in which desorption accompanied by hydration and ionization was the rate controlling step. The experimental results were reviewed in the light of this mechanism and appeared to show no serious contradictions, so this model is put forward as a postulate of the reaction of galena with oxygen in sodium hydroxide solution. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate

In the course of the experimental work conducted it was found that when galena was treated with chromate salts or dichromate salts in an aqueous solution, lead chromate identified by infrared spectroscopy was the main species adsorbed on the galena surface. The formation of chromium hydroxide or chromium oxide was not observed. Thermodynamic considerations of the Pb-Cr-S-H₂0 bulk system indicate the very stable character of lead chromate as shown in the potential-pH diagram constructed in this study. It is also seen that no stable domain of lead dichromate exists. The adsorption rate as well as adsorption amount of dichromate at the pseudo-equilibrium condition increases with the decrease in pH value. This phenomenon supports the fact experienced in galena flotation that a dichromate salt is a much more efficient depressant than is an equivalent chromate salt. The desorption of xanthate from galena surfaces covered with more than a monolayer thickness of xanthate was found to be possible by adding chromate salt to the system, whereas chromate desorption from galena surfaces due to xanthate addition was not observed. It was found that under comparable conditions xanthate adsorbed on lead chromate surfaces oxidized to dixanthogen much more readily than xanthate adsorbed on galena surfaces. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate

Thesis (PhDApSc(MineralsandMaterials))--University of South Australia, 2002