No description available.

Thesis (M.S.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains ix, 130 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 128-130).

[Truncated abstract] The influence of environmental conditions and properties of pyritic shale in the mining waste from Mt. Whaleback in Western Australia, in particular the inclusions and encapsulation of pyrite on the oxidation of pyritic shale and its subsequent acid mine drainage, was studied by employing an isothermal batch reactor system and QEMSCAN technique. The experimental technique was validated by comparing the experimental results obtained in this study with the literature data. It was found that the presence of water significantly accelerates the rate of shale oxidation. Weathering of the shale samples was found to influence the O2 consumption rate. It was also found that shale properties have a major effect on the oxidation rate and thereby affect the acid generation. Static test methods (Sobek and Lawrence) were employed to test the Neutralisation Potential (NP) of more than 100 actual and composite samples including pyritic shale samples, rock samples, mineral samples, various pyrite-mineral, pyrite-shale, and pseudo-shale blends. The influence of sample properties (bulk elemental composition, and mineralogy), test technique (Sobek and Lawrence) and associated variables (acid strength and volume) on the acid neutralisation potential of the samples was studied. It was found that the Sobek method produced consistently higher NP results under comparable acid conditions to those obtained with the Lawrence method. The theoretical NP values of individual minerals were calculated based on the mineral composition combined with the acid neutralising equations and ideal chemical formula. ... To experimentally model the major mineral phases, 11 minerals were used to produce pyrite-mineral blends and pseudo-shales, whose compositions mimic those of the actual shales studied. Mineral blends were employed to evaluate and contrast their individual acid generation or neutralisation behaviour with binary and higher order interactions. Blends of pyrite with some selected shales were also employed in this study. It was found that interactions can occur between the multiple mineral components which can enhance the rate of acid generation beyond that of the individual behaviour. It was found that the products from the pre-oxidation of shales, the properties and morphology of a sample such as the surface area, encapsulation, the mineralogy and pH all play a significant role in the acid generation and neutralisation rates. However, the absolute rate of acid generation appears to be most sensitive to the components such as Fe3+, which contribute to its reaction mechanisms. This investigation has provided a scientific insight into the acid generation and neutralisation behaviour of pyritic shale in relation to its mineralogy. It was found that the relative instantaneous rates of acid generation and consumption for individual minerals can be significantly different to that of their total potentials for acid generation and neutralisation. The significantly different behaviour of the actual and pseudo shales suggests that at low pH, there may be other mechanisms underlying the net capacity and rates of shales to generate or consume acid than bulk mineralogy. These findings have significant implications to the mining industry operating in reactive grounds.

Physicochemical factors, algal diversity, taxonomic composition and standing crop were investigated across a broad gradient of AMD stress in streams and rivers. 52 sites were surveyed in the vicinity of Greymouth, Reefton, Westport and Blackball, on the West Coast, South Island. Seven sites in the Reefton area were sampled from April 2006 - February 2007 to establish changes over time in benthic algal communities of AMD and reference streams. Longitudinal change and ecosystem recovery were also investigated by sampling eight sites down Devils Creek, Reefton, and two of its tributaries. AMD has negative impacts on algal diversity, generally increases the dominance of certain taxa and, where metal oxide deposition or hydraulic disturbance are not great, can lead to algal proliferations. These proliferations were chlorophyte dominated, predominantly by filamentous Klebsormidium acidophilum. From the general survey a total of 15 taxa were identified from the most severely impacted sites (pH <3.6), which included both acidophiles and acidotolerant algae. Multivariate analyses strongly suggest that pH was the dominant factor controlling taxonomic occurrence of diatoms, macroalgae and the structure of the total assemblage. Other factors such as conductivity, metal oxide deposition, temperature, depth, month, geographic location and altitude were also important. Algal communities changed over time and this became more marked as AMD impact decreased. This was presumably due to AMD stressors reducing diversity, and thus the available scope for assemblage change. Longitudinal differences in assemblage structure within Devils Creek appeared to be in response to dilution of AMD in upper reaches and to changes in natural physical features such as gradient in mid and lower reaches. After a distance of 7.2 km the physicochemical effects of AMD and suspended clay inputs were minimal. At this site and at several previous sites, the assemblage exhibited a degree of recovery towards that found at unimpacted sites. A range of algae found in the broad scale-survey are potentially useful 'sensitive' indicators. These included: Heteroleibleinia purpurascens; Achnanthes oblongella; Oedogonium sp. and Spirogyra sp. In contrast: Euglena mutabilis; Navicula cincta; K. acidophilum; Microspora quadrata and Microthamnion kuetzingianum may be useful 'tolerance' indicators. These data show that AMD has a range of negative impacts on algae, and algae may be a useful tool for monitoring these impacts in West Coast streams.

The waste products acid mine drainage formed during coal mining and fly ash from coal burning power generation, pose substantial environmental and economic problems for South Africa. Eskom has developed a remediation system employing alkaline fly ash to neutralize and precipitate heavy metals from toxic acidic acid mine drainage streams. The aim of this study was to assess the microbial diversity in and microbial impact on this remediation system.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. 2014. / Sugar cane bagasse and switch grass were used to investigate their potential in the remediation (decreasing metal ion concentration and increasing pH) of Acid Mine Drainage (AMD) and the possibility that the AMD residue sludge containing cellulose could be further hydrolysed using a commercial cellulase enzyme system to produce glucose for bioprocesses. In general both the feedstocks series appeared to increase pH and reduce dissolved iron concentration after being incubated with AMD for a period of 14 weeks at room temperature. The milled switch grass was shown to have a greater remediating effect on AMD, raising the pH from 2.11 to 5.46, and decreasing iron concentration from 500mg/l to 174mg/l, a decrease of 62%. The sugar cane bagasse was shown to have the least remedial effect, increasing pH from 2.11 to 2.38, and only reducing iron concentration by 30%. The 2‐5cm switch grass raised the pH from 2.11 to 3.86, and the iron concentration was reduced from 500mg/l to 283mg/l, a 42% reduction. The milled grass series was chosen for further enzymatic hydrolysis. The milling reduced the size of the switch grass and destroyed the cell structure making it more accessible to AMD treatment. This also allowed the enzyme in the hydrolysis to penetrate to the fibres and reach the sugar oligomers. The sludge of the AMD treated switch grass was incubated with cellulases enzymes for 24 hours at 50oC, producing glucose concentration of up to 4,86mg/ml.

A research report submitted to the Faculty of Science, University of the Witwatersrand in partial fulfillment of the requirements for the degree of Masters (MSc. by Course work and Research Report) 30th September, 2015 / Acid Mine Drainage (AMD) refers to the seepage or runoff of acidic water from abandoned mines into the surrounding environment. Acid mine drainage is considered a serious long term environmental threat associated with mining. This study was conducted on the Varkenslaagte canal or stream which flows from north to south within the AngloGold Ashanti West Wits gold mining operation, 75 km west of Johannesburg, and receives AMD from tailings storage facilities (TSFs) located on both the northern aspect and the western aspect of the catchment. On the Varkenslaagte, 17 reed beds were planted between 1-12-2011 and 12-9-2012, in a series of shallow excavated depressions. This study was conducted in 2013 and 2014, and aimed to ascertain: (i) whether there is any temporal difference (autumn – end of the rainy season, versus winter – mid-dry season, for 2013 and 2014 combined) in selected fresh-water quality parameters and concentrations of AMD contaminants in the flowing waters in the engineered reed beds; - this was observed, as higher concentrations were recorded in winter than in autumn, for some of the selected water quality parameters, in both survey years; (ii) to determine if vertical changes exist in the elements down the sediment profile from the surface to a depth of approximately half a metre; - conspicuous vertical changes were not evident; and also; (iii) to provide a baseline for monitoring the post clean-up state of the upper Varkenslaagte, and conclude whether the reed bed system is retaining AMD contaminants (major ions, trace and major elements). Chemical variations in water and sediment samples were measured in situ in April/May 2013 and July 2014, and water samples and sediment cores collected for laboratory analyses. Water samples were collected from three points (inflow, middle and outflow) at each of 15 reed beds (RBs, numbered RB 1 -15) in receipt of AMD from two directions (downstream and laterally from TSFs on the northern and western aspects). Ion Chromatography was used to detect chloride (Cl-) and sulphate (SO42-), Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) were used to identify major and trace elements; iron (Fe), magnesium (Mg), manganese (Mn), potassium (K), cobalt (Co), nickel (Ni), lead (Pb), copper (Cu) and zinc (Zn) in the water samples whereas X-Ray Fluorescence (XRF) analysis for elements was conducted on surface sediments (0-2cm; additional analyses of sediment core samples at depths 2-5 cm, 5-10 cm, 10-20 cm and 20 -30 cm were analyzed but were not considered further). The water in the reed beds was moderately acidic to within the target range. It ranged from pH 5.17 to 6.51 in April, 2014 (approaching the end of the wet season) (P < 0.05) (P = 0.0001) to slightly higher values of pH 5.45 to 6.82 in July, 2014 (mid-dry season) (P = 0.0053). Marginal acidity is above pH 6. A pH of 6.5 – 7.5 is within the target water quality range (TWQR) on the Highveld. High electrical conductivity (EC) values were found, ranging from 3500 – 4600 μs/cm in April and 2600 – 5500 μs/cm in July, though EC values can be higher on much of the South African gold mining Highveld. Lateral influx of AMD from the western TSFs was visually observed into two of the southernmost Varkenslaagte stream reed beds (at RBs13 and 15) during both April and July sampling. In 2014, the Varkenslaagte was still flowing from reed bed to reed bed, although very slowly, similar to 2013. Chloride, sulphate and metal concentrations were high relative to target water quality ranges in most of the reed beds in during April and July, 2014. Although higher concentrations in the sediment suggest that the reed beds are effective in capturing and retaining contaminants in sediment and root mass, the concentrations in the water in reed beds 1-15 still exceeded the target water quality ranges for aquatic ecosystems in South Africa (DWAF, 1996) and the World Health Organization (WHO) guidelines for drinking water quality (WHO, 2004). However use of the water from the Varkenslaagte by humans and livestock is prohibited by the Department of Water and Environmental Affairs, and the National Nuclear Regulator. The bar charts comparing 2013 and 2014 selected water quality data showed that during winter/drier periods with no rains, the rate of evaporation exceeded dilution; this was observed by the slightly lower pH values recorded across the reed beds in July, 2013 and 2014, in comparison with the slight higher pH values recorded across the reed beds in May, 2013 and April, 2014. The bar charts also showed that the highest EC was recorded in the winter of 2014. It was also observed from the principal component analyses (PCAs) that EC, sulphate and pH, in combination with Mg and Fe, were responsible for most of the variation in the water quality data for the two survey years, 2013 and 2014. Following the findings from this study, it is recommended that monitoring of the site should also address whether the reed beds and other control measures that have been put in place (riparian woodlands and windmill pumps) will be adequate to control the lateral seepage from the Western TSFs at some of the southernmost reed beds.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science WITS University, Johannesburg, 2013 / Occurring parallel to the developments in imprinting technology are magnetic materials which are being applied increasingly in environmental remediation, medicine, biotechnology and many other fields. Combining the imprinting effects of the polymer and nano magnetic particles yields composite materials which are both selective to the template and magneto responsive for easy polymer removal from aqueous solutions. In this study, magnetic ion imprinted polymers with high recognition for uranyl ion (UO2 2+) in the presence of competing ions were synthesized by bulk and precipitation polymerizations. The uranyl template was removed from the magnetic polymer matric by 1M HCl and 1M NaHCO3 leachants to form cavities which were complimentary in shape and size to the template. Full characterization of the magnetite and magnetic polymers was achieved by use of the following characterization techniques: Raman spectroscopy (RS), Transmission electron microscopy (TEM), Energy dispersive spectrometry (EDS), Powder X-ray diffraction (PXRD) analysis, Brunauer, Emmett and Teller (BET) analysis, Ultraviolet visible (UV-vis) spectroscopy, Fourier-transform infrared (FTIR), Thermo-gravimetric analysis (TGA), Carbon, hydrogen, nitrogen and sulphur (CHNS) analysis, Diffuse reflectance spectroscopy (DRS) and Atomic force microscopy (AFM). Parameters which were optimized included sample pH, which gave an optimum value of 4. Magnetic IIP and NIP amounts which gave maximum adsorption capacities were found to be 50 mg for both of these adsorbents. The optimum contact time was found to be 45 minutes. The performance of all magnetic ion imprinted polymers (IIPs) was expectedly superior to that of the corresponding non imprinted polymers (NIPs) in all adsorption studies. The first rate constant (k1) and correlation coefficient (R2) values evaluated for the pseudo first order were found to be between 0.048-0.093 min-1 and 0.602-0.991 min-1, respectively. For the pseudo second order, second rate constant (k2) and correlation coefficient (R2) were found to be between 0.273- 0.678 and 0.9811-0.9992, respectively. The selectivity order observed was as follows: UO2 2+ > Fe3+ > Pb2+ > Ni2+ > Mg2+. The magnetic polymers selective to Cr(VI) were also synthesized and were leached with HCl to remove the template. The synthesized Cr(VI) magnetic polymers, the optimum pH obtained was 4 for both the magnetic IIP and the corresponding NIP. The amount of the adsorbent which gave the maximum adsorption was determined to be 20 and 65 mg for the magnetic IIP and NIP, respectively. A Cr(VI) concentration which was adsorbed maximally was from 5 mg L-1 which was therefore taken as the optimum. The maximum adsorption capacities for the magnetic polymers were 6.20 and 1.87 mg g-1 for the magnetic IIP and NIP, respectively. The optimum time for the adsorption of the Cr(VI) analyte was determined as 40 minutes. Investigation of the order of selectivity of anions followed the trend: Cr2O7 2- SO4 2- F- NO3- -.

A dissertation is submitted as MSc research project in partial fulfilment of the requirements for the degree of Master of Science in the School of Geography, Archaeology and Environmental Studies. July 2016. / A major cause of environmental problems, in the vicinity of mine tailings in and around Johannesburg, is Acid Mine Drainage (AMD). In most research, engineered wetlands are used to ameliorate AMD with the use of vegetation to remove or extract heavy metals from the soil (i.e. phytoremediation). Phytoremediation has been defined as a technology that uses plants to extract or immobilize contaminants in soils and waters (Torresdey, 2007). The aim of this study was to assess and quantify the mass pool size of contaminants (macronutrients, micronutrients, non-essential trace elements) within and between a subset of paddocks from various compartments including sediments, aboveground biomass (shoots –stems and leaves), and belowground biomass (roots and rhizomes) of the two wetland plant species present (P. australis and S. corymbosus ). Analyses were done on the wetland paddocks in situ and ex situ applying different methods, water sample metal cations were analysed by ICP-MS and the major anion analysis by chromatography and Ion Chromatography (IC). The sediment and plant samples were subject to X-Ray fluorescence (XRF) analyses of major elements and trace elements. Although analysis was undertaken for numerous trace and metal elements, only a few macronutrients, micronutrients, and non-essential elements with significant importance to the West Wits Mining Operation were selected for this study. The stream water test strips yielded poor results for this extremely contaminated plume receiving environment this suggests that in this system they are not a useful substitute for conventional laboratory analyses. Of the elements tested, only S showed significant differences in concentrations in plants between paddocks, with the highest concentrations and mass in the downstream paddocks ww6 and ww7. These paddocks also had the greatest masses of S in sediments, and water concentrations were also highest in paddocks ww4, ww6 and ww7. P. australis accumulated highest elemental mass than S. corymbosus, with the highest Zn mass of 93%. P. australis accumulated double the mass of U, Cu, Cl, Ca. In both plants, the roots consistently had highest elemental concentration with sequence often as follows roots> shoots> rhizomes. Sediment element mass accumulation of most tested elements significantly increased with depth, except for Zn and U, which decreased with depth. There are few significant differences in the mass distribution of the elements analysed between paddocks, which is assumed to reflect either the heterogeneity in the underlying sediments following construction of the wetlands, or lateral inputs into the system as seepage from other TSFs. Key words: AMD, Wetland, Varkenslaagte Canal, West Wits Mining Operation, metals, sediment, S. corymbosus, P. australis, ICP-MS, XRF. / LG2017

Acid rock drainage (ARD) is recognised as one of the most serious environmental issues currently facing the mining industry. ARD management strategies rely heavily on the ability to measure the ARD potential of waste materials to ensure strategies are appropriate to the ARD risks. It is apparent that improvements to the understanding of ARD test methods and development of methods to better represent the ARD potential of samples will contribute significantly to the value and reliability of ARD assessment. The research described in this thesis focused on critical assessment and improvement of: ARD test methodology; approach to testing; and interpretation of results for coal mine wastes. Kaltim Prima Coal Mine (KPC) in Kalimantan, Indonesia was selected as a case study site to help focus the research, with the understanding that the broad similarities of coal sequences in general would allow broader application of the findings. / Thesis (PhDApSc(MineralsandMaterials))--University of South Australia, 2005