Background: Tailings dam workers are exposed to tailings dust that has a potential health risk due to the element contents in the dust. The extent of exposure of tailings dam workers is unknown. Consequently, the elements, level of exposure, the potential adverse effects to health, compliance to legislative requirements and the efficiency of the current control measures were investigated. Design and Method: During the trials, 69 personal dust samples were collected during three full production shifts from tailings dam workers in three different tailings dam environments. The field filters were weighed to calculate the total dust concentrations. Bulk samples and field filters were analysed using the 32-element and particle size distribution scans. The between-dam, between-days and between-group variances were determined to assess the changes in exposure levels. Results: The tailings dam workers were not overexposed to tailings dust. Mean exposures were below the OEL for PNOC, measuring 0,124 mg/m3 (TD 1) 0,366 mg/m3 (TD 2) and 2,956 mg/m3 (TD 3). Three outliers in the data were present in TD 3 and exceeded the action level for PNOC. A major part of the particle size distribution consisted of inhalable sizes (>I0 μm). Cyclone tailings dams have smaller particle sizes than spigot tailings dams, though 85% of the particles in all tailings dams were larger than 10 μm. Some elements identified in the dust have potential respiratory health effects. No significant differences existed between the three tailings dams regarding tailings dust concentrations (p=0,527 on 5% significant level and p=0,292 on 10% significant level). There was, however, a significant difference on a 5% significant level between the days (p=0,003 and p=0,006). The workers on the cyclone tailings dams had smaller exposures than workers on the spigot tailings dams, and the pipeline labourers were more exposed than the mudguards. The tailings dams did comply with legislative control measures. However, washing facilities for the cleaning of overalls due to elements in the dust, such as nickel, chromium and manganese need to be considered. Workers need to be educated in work practices and procedures, personal hygiene and symptoms that can be experienced after exposure. Engineering control measures such as water sprayers covering the entire tailings dam, the use of fixed or temporary windscreens in the area where work is done and covering of the roads on the tailings dam with gravel or water spray can be considered as dust suppressant controls. Conclusion: The study met the issues set out in chapter 1, hypotheses were rejected and accepted and future studies were suggested. / Thesis (M.Sc. (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2007.

Historically, irresponsible mining companies have escaped their duty to rehabilitate. The Mineral Petroleum Resources Development Act does not oblige mining companies to rehabilitate if their operations ceased before the Minerals Act came into force. In the court case De Beers Consolidated Mines v Ataqua Mining (Pty) Ltd and others 2006 1 SA 432 (T), the court held that the Mineral Petroleum Resources Development Act is not applicable to tailings dumps that were created through mining that had been conducted under the Minerals Act. This ruling leaves unanswered the question about who would be liable to rehabilitate old order tailings dumps once such tailings dumps are re-mined or not mined at all. The aim of this dissertation is to determine whether companies that ceased mining operations before the Mineral Petroleum Resources Development Act came into effect could be held liable for rehabilitation by introducing the scenario that applied in the De Beers court case. / Thesis (LL.M. (Environmental Law))--North-West University, Potchefstroom Campus, 2010

Historically, irresponsible mining companies have escaped their duty to rehabilitate. The Mineral Petroleum Resources Development Act does not oblige mining companies to rehabilitate if their operations ceased before the Minerals Act came into force. In the court case De Beers Consolidated Mines v Ataqua Mining (Pty) Ltd and others 2006 1 SA 432 (T), the court held that the Mineral Petroleum Resources Development Act is not applicable to tailings dumps that were created through mining that had been conducted under the Minerals Act. This ruling leaves unanswered the question about who would be liable to rehabilitate old order tailings dumps once such tailings dumps are re-mined or not mined at all. The aim of this dissertation is to determine whether companies that ceased mining operations before the Mineral Petroleum Resources Development Act came into effect could be held liable for rehabilitation by introducing the scenario that applied in the De Beers court case. / Thesis (LL.M. (Environmental Law))--North-West University, Potchefstroom Campus, 2010

Large voids created by underground mining are backfilled to provide regional ground support. This thesis examines using conventional oedometer techniques and electromagnetic (EM) techniques to characterize consolidation and binder hydration in mine backfill so that EM monitoring can be used in the field to provide real-time feedback to operators to optimize the backfilling process. New techniques are given for interpreting the full range of deformation (initial compression, primary and secondary consolidation). Deformation due to initial compression is non-trivial and may have to be accounted for in numerical back-analyses of field case studies. EM parameters are sensitive to binder content, progress of hydration and loss of water caused by consolidation and binder hydration. The integrated interpretation of consolidation and EM behaviours has significant potential impact on real-time monitoring of mine backfill operations, and recommendations are made to advance the technique for this purpose.

Petroleum coke-derived activated carbons were prepared and used for the adsorptive removal of a single-ring naphthenic acid (NA) from synthetic oil sands tailings pond water (TPW). The overall adsorption process was found to be intra-particle diffusion-controlled. The Weber-Morris intra-particle diffusion rate constants decreased from 7.43 to 1.23 mg/g min0.5 after activated carbon was post-oxidized with oxygen, suggesting a hindering effect of oxygen surface groups. The Freundlich model fit of the equilibrium adsorption isotherms and the small negative ΔHo pointed to a physisorption-dominated process and the importance of specific surface area. It was estimated that about 2.7 g/L of basic CO2-activated carbon is needed to reduce NA concentration from 120 mg/L to 2.5 mg/L (~98% removal) in synthetic TPW. However, equilibrium adsorption capacity was found to vary significantly after oxygen or nitrogen groups were introduced onto the surface. Therefore, there is a potential for enhanced adsorption by chemical functionalization of carbon.

Large voids created by underground mining are backfilled to provide regional ground support. This thesis examines using conventional oedometer techniques and electromagnetic (EM) techniques to characterize consolidation and binder hydration in mine backfill so that EM monitoring can be used in the field to provide real-time feedback to operators to optimize the backfilling process. New techniques are given for interpreting the full range of deformation (initial compression, primary and secondary consolidation). Deformation due to initial compression is non-trivial and may have to be accounted for in numerical back-analyses of field case studies. EM parameters are sensitive to binder content, progress of hydration and loss of water caused by consolidation and binder hydration. The integrated interpretation of consolidation and EM behaviours has significant potential impact on real-time monitoring of mine backfill operations, and recommendations are made to advance the technique for this purpose.

Petroleum coke-derived activated carbons were prepared and used for the adsorptive removal of a single-ring naphthenic acid (NA) from synthetic oil sands tailings pond water (TPW). The overall adsorption process was found to be intra-particle diffusion-controlled. The Weber-Morris intra-particle diffusion rate constants decreased from 7.43 to 1.23 mg/g min0.5 after activated carbon was post-oxidized with oxygen, suggesting a hindering effect of oxygen surface groups. The Freundlich model fit of the equilibrium adsorption isotherms and the small negative ΔHo pointed to a physisorption-dominated process and the importance of specific surface area. It was estimated that about 2.7 g/L of basic CO2-activated carbon is needed to reduce NA concentration from 120 mg/L to 2.5 mg/L (~98% removal) in synthetic TPW. However, equilibrium adsorption capacity was found to vary significantly after oxygen or nitrogen groups were introduced onto the surface. Therefore, there is a potential for enhanced adsorption by chemical functionalization of carbon.

Thesis (Ph. D.)--McMaster University (Canada), 1990. / Source: Dissertation Abstracts International, Volume: 52-10, Section: B, page: 5258. Supervisor: O.E. Hileman, Jr.

Thesis (M.Sc.) - Carleton University, 2006. / Includes bibliographical references (p. 142-146). Also available in electronic format on the Internet.

Thesis (M. Eng.(Geotechnical Engineering))--University of Pretoria, 2003. / Includes bibliographical references.