Ph.D. (Geography) / The focus of Aeolian research has mainly been on wind-blown dust from desert and arid areas. Numerous dust emission schemes have been developed over the years aimed at accurately estimating dust emission rates from various soil types and land use surfaces. Limited research has been done on wind-blown dust from smaller area sources – such as mine tailings and ash storage facilities. Lately, the concern about the environmental and health impacts, caused by dust from mine tailings storage facilities and ash disposal sites, has become more prominent, calling for better methods in determining dust emissions and their related impacts. This thesis established a practical approach for wind-blown dust emissions estimation and dispersion modelling from mine waste and ash storage facilities for the purpose of legal compliance assessment. Extensive research on the physics of wind erosion has been done over the past decade, compelling the re-evaluation of previously applied techniques. The latest and most widely applied dust emission schemes are evaluated to determine, through systematic testing of parameterisation and validation, using empirical mine waste and coal ash data, a best-practice prescription for quantifying wind-blown dust emissions and determining effects on a local scale using commercially available dispersion models. The applicability of two dust-flux schemes, (one developed by Marticorena and Bergametti (1995) and the simplified Shao 2004 scheme, as reported in 2011) for the quantification of wind-blown dust emissions, were tested using site specific particle size distribution data, bulk density and moisture content from six gold- and one platinum- tailings storage facilities and from two ash storage facilities. The availability of the required input parameters and the uncertainty associated with these parameters, were tested. The dependency of the Shao et al. (2011) model on plastic pressure (P) and the coefficient cy, both of which are not easily determined, added to the uncertainty of the emission rates. In this study, P and cy were both interpolated using the range limits provided by Shao (2004) for natural soils. By calculating P, using the salt and calcium carbonate content, similar values were obtained. The minimally disturbed dust fraction, as required by the Shao et al. (2011) scheme were derived from particle size distribution analysis but found to be more representative of the fully disturbed particle size faction (𝜂fi) and therefore needed to be corrected to represent the minimally disturbed particle size faction (𝜂mi) through the application of a correction factor, CF𝜂mi. Specific attention was given to the quantification of the threshold friction velocity (u*t) and the threshold velocities (u*), and how these two parameters relate to each under variable wind speed and time durations. This was tested using sub-hourly averaged meteorological data, one set reflected 5-minute intervals and the other 10-minute intervals. Dependent on the frequency and strength of the sub-hourly wind gusts, the resulting dust-flux rates were found to vary significantly when based on hourly averaged wind data in comparison with 5- and 10-minute wind data. Dispersion models are useful tools in air quality management. Whereas ambient monitoring provides actual ambient concentrations for specific pollutants at set locations, atmospheric dispersion models can be used to simulate any number of pollutants and determine the impacts at any location within the modelling domain. These dust-flux schemes of Marticorena and Bergametti (1995) and Shao et al. (2011) have been coupled with the US EPA regulatory Gaussian plume AERMOD dispersion model for the simulation of ground level concentrations resulting from wind-blown dust from mine tailings facilities. For this study, two Case Studies were evaluated; one included two of the gold mine tailings and the second focused on the platinum tailings. Simulated ambient near surface concentrations were validated with ambient monitored data for the same period as used in the model. For the Marticorena and Bergametti (1995) dust-flux scheme, only z0 had to be adjusted to provide a good fit with measured data – whereas the Shao et al. (2011) scheme resulted in significantly higher concentrations, resulting in an over-prediction of the measured data. By applying the correction factor, CF𝜂mi, to the minimally disturbed dust fraction, the predicted concentrations improved considerably. The coupling of the dust-flux schemes with a regulatory Gaussian plume model provided simulated ground level PM10 concentrations in good agreement with measured data. The best correlation was found under conditions of high wind speeds when the prevailing wind was from the direction of the tailings storage facility. This thesis demonstrates that simulated impacts from complex source groups can be performed, within an acceptable range of certainty, using widely applied dust-flux schemes. These dust-flux schemes, developed primarily for large-scale desert and arid areas, have been demonstrated to be applicable also to small-scale sources, of the order of 1 km2, and can be coupled to regularly available dispersion models for impact evaluations of wind-blown dust. The value of this improved approach to the mining and mineral processing industries are substantial, allowing for more accurate health risks and adverse environmental assessments from wind-blown dust from large material storage piles, a source category that has hitherto been difficult to quantify.

A graphical system was developed to represent airborne air quality monitoring data. The representations developed included three—dimensional spatial mapping, percentage and frequency distributions, and altitude—based scatter diagrams. Elementary statistical analyses and correlations of the measured parameters were also performed. Data gathered in eight flights to the Shenandoah National Park during the summer months of 1981 were analyzed. Sulfur dioxide levels were found to be in the 5 - 15 ppb range, nitrogen oxides were in the 4 — 10 ppb range, nitrous oxide was in the 2 - 5 ppb range, nitrogen dioxide was in the 2 - 5 ppb range, ozone was in the 35 - 70 ppb range and visual range was in the 5 — 90 mile range. The data representation system proved to be an easier and more useful method of displaying the data than the previously existing system. / Master of Science

No description available.

Previously, issues concerning the use and conservation of the natural resources were restricted to certain groups of individuals, normally those considered to be scientific experts. However with the emergence of sustainable development and the adoption of its principles therein, there has been increased community concern over environmental quality issues resulting in pressure for transparency in environmental decision-making processes. The result has been a dramatic expansion in the number of organisations at the local, national and global scales committed to environmental improvement. This in turn has let to dramatic changes in the role of the public in decisions relating to natural resource management. Participatory development is now acknowledged as critical in achieving sound environmental management. The initiation of community-based environmental decision-making has led to the formation of new and interesting partnerships. Environmentalists, communities, policy makers and business people have begun to work together in an attempt to find consensus concernIng environmental problems and related socio-economic inequalities. This has resulted in the development of new ways of integrating local and scientific knowledge systems. This thesis illustrates community-based environmental decision-making in the management of the use of the south coast of Durban. It outlines a partnership, through the formation of the Permit Advisory Panel (PAP), comprising industry (Sappi Saiccor), government, through its Department of Water Affairs and Forestry, environmental organisations, and the local people in the monitoring of the impacts of effluent produced by the industry and disposed of into the sea. The aim of this thesis is to develop an alternative methodology that will be acceptable to all stakeholders, for the collection and analysis of data in the monitoring of the Sappi Saiccor effluent. This was achieved through the following objectives: to develop a methodology for the collection and analysis of data, to assess the performance of the new pipeline in terms of reduced aesthetic impacts of the effluent, to assess the role of local knowledge in the monitoring process, and finally to assess the role of this study in the functioning of the PAP. This thesis attempts to integrate qualitative and quantitative methodologies. The subjective local data collected by the divers is analysed using statistical methods to assess the impacts of the effluent on marine water quality and the effect the new pipeline has had in reducing these impacts. Qualitative surveys such as questionnaires and interviews were administered to assess the role of local knowledge in the monitoring process and also to assess the role this study has had in the functioning of the PAP. The statistical analysis did not reveal any major improvement in underwater visibility since the pipeline was extended. There is a 6% and 4% improvement in the number of effluent days and visibility respectively. This however is due to some limitations inherent in the data collection process, and as a result the improvement brought about by the pipeline extension has been toned down. An effluent and visibility index is therefore recommended as an alternative method of data collection and analysis to reduce the level of inaccuracy. The role of local knowledge is perceived by many of the PAP members as vital in the monitoring process. This study was therefore thought of as an important step in validating this local knowledge such that it can be a reliable data source to be used in the monitoring process. It also played an important role in resolving the conflict between the PAP members. It is therefore recommended that the divers data should be continually used in the monitoring process, though the divers have to be more actively involved. The PAP is therefore tasked with liasing with the community members, especially the divers such that they can assume a more active and responsible role within the PAP. They should be involved in the development of the methods of data collection and analysis. / Thesis (M.A.)-University of Natal, Durban, 2002.