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Geochemical and mineralogical characterization of gold mine tailings for the potential of acid mine drainage in the Sabie - Pilgrims's Rest GoldfieldsLusunzi, Rudzani 21 September 2018 (has links)
MESMEG / Department of Mining and Environmental Geology / This study entails geochemical and mineralogical characterization of gold tailings of Nestor Mine and Glynn’s Lydenberg Mine of the Sabie-Pilgrim’s Rest goldfields. A total of 35 samples were collected and were analysed for chemical composition (XRF and ICP-MS), mineralogical composition (XRD). In addition, acid-base accounting (ABA) techniques had been conducted to predict the potential for acid mine drainage. Seepage from Nestor tailings dump and water samples from the adjacent Sabie River were also collected and analysed by means of inductively coupled plasma mass spectrometry (ICP-MS) and immediate constituent (IC) -analytical techniques. The study revealed that Sabie-pilgrim’s rest goldfield is characterized by both acid generating and non-acid producing tailings, and this is attributed to variations in the mineralogy of source rocks. Gold occurred within the Black Reef Quartzite Formation in the Nestor Mine and within the Malmani Dolomite in the case of Glynn’s Lydenburg Mine. Mineralogy and bulk geochemical analyses performed in this study showed a clear variation in the chemistry of Nestor Mine and Glynn’s Lydenburg Mine tailings. Predominant oxides in Nestor mine tailings samples are SiO2 (ranging from 66.7-91.25 wt. %; followed by Fe2O3 and Al2O3 (in range of 0.82-15.63 wt. %; 3.21-12.50 wt. % respectively); TiO2 (0.18-10.18 wt. %) and CaO (0.005-3.2 wt. %). Also occurring in small amounts is CaO (0.005-3.2 wt. %), K2O (0.51-2.27 wt. %), MgO (0.005-1.46 wt. %), P2O5 (0.029-0.248), Cr2O3 (0.013-0.042 wt. %) and Na2O (0.005-0.05 wt. %). The samples also contain significant concentrations of As (137-1599 ppm), Cu (34-571 ppm), Cr (43-273 ppm), Pb (12-276 ppm), Ni (16-157 ppm), V (29-255 ppm), and Zn 7-485 ppm). In the Glynn’s Lydenburg Mine tailings SiO2 is also the most dominant oxide ranging between 47.95 and 65.89 w%; followed by Al2O3 (4.31 to 16.19 wt. %), Fe2O3 (8.48 to 11.70 wt %), CaO (2.18 to 7.10 wt. %), MgO (2.74 to 4.7 wt. %). Occurring in small amounts is K2O (1.12-1.70 wt. %), MnO (0.089-0.175 wt. %), P2O5 (0.058-0.144 wt. %) and Cr2O3 (0.015-0.027 wt. %). Arsenic (As), is also occurring in significant amounts (807-2502 ppm), followed by Cr (117-238 ppm), Cu (10-104 ppm), V (56-235 ppm), Ni (45-132 ppm), Pb (13-63 ppm) and Zn (90-240 ppm). Nestor Mine tailings associated with Black Reef Formation mineralization have net neutralizing potential (NPR) <2, hence more likely to generate acid; and their acid potential (AP) ranges 1.56 to 140.31 CaCO3/ton and neutralizing potential (NP) range from -57.75 to -0.3 CaCO3/ton. Glynn’s Lydenburg Mine tailings dump which is
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associated with dolomite mineralization, however, was not leaching acid. Based on acid-base accounting results, these tailings have more neutralizing potential (ranging between 57.6 and 207.88 CaCO3/ton) than acid potential (ranging between 7.5 and 72.1 CaCO3/ton); and their NPR>2, hence unlikely to produce acid. This is confirmed by paste pH which was in the ranges between 7.35 and 8.17. Tailings eroded from Nestor Mine tailings dump were also found to be characterized by high content of metals and oxides, namely, As, Cu, Ni, Pb, V, and Zn with SiO2, Fe2O3 and TiO2. The tailings were observed eroded into the Sabie River where AMD related precipitate (yellow boy) was also observed, indicating further oxidation downstream. Field observations, onsite analyses of water samples and laboratory results revealed that Nestor Mine tailings storage facility discharges acid mine drainage with considerable amounts of Al, As, Cu, Fe, Mn, Zn and SO4 and very low pH exceeding the limit as per South African water quality standards. High concentrations of these metals have toxicity potential on plants, animals and humans. Upon exposure to oxygen and water, tailings from Nestor Mine are more likely to generate acid mine drainage that can cause detrimental effect to the environment and the surrounding communities. Potential pollutants are Fe, Mn, Al, As, Cr, Cu, Ni and Pb. Tailings from Glynn’s Lydenberg showed no potential for acid mine drainage formation. / NRF
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Green synthesis of geopolymeric materials using Musina Copper Mine Tailings: a case of beneficial management of mine tailingsMatidza, Murendeni 17 September 2019 (has links)
MENVSC / Department of Ecology and Resource Management / Mine tailings (MT) have been a global problem due to the environmental impacts the
waste generates such as air, soil and water pollution. The detrimental impacts include
a global problem such as acid mine drainage (AMD) which has been difficult to cleanup. Several studies have been conducted to find alternative measures in reducing or
mitigating impacts such as AMD and air pollution. Several studies have revealed how
alumino-silicate mineral waste can be used as raw material to produce construction
materials. This study aimed at evaluating the potential of synthesizing a geopolymer
material from Musina copper mine tailings. Tailings were characterized for their
physicochemical and mineralogical compositions using standard laboratory techniques
in order to evaluate suitability in geopolymerization.
First section of the results presented physicochemical and mineralogical
characterization of the Musina copper tailings together with the bioavailability of the
chemical species. It was observed that the tailings are mainly composed of SiO2 and
Al2O3 as the major oxides indicating that they are aluminosilicate material.
Mineralogical analysis revealed dominance of quartz, epidote and chlorite as the major
minerals. The bioavailability assessment showed that largely Cu and Ca are
bioavailable and highly soluble in an aqueous solution while Al, Mg, Ni, Co, Cr and Fe
have a high proportion in non-labile phase.
Second section presented the preliminary results wherein the potential application of
Musina copper tailings in geopolymerization was evaluated. The results showed that
Musina copper tailings can be used to synthesize a geopolymer material. However, it
was recommended that several parameters influencing geopolymerization need to be
evaluated. The third section presented the evaluation of optimum parameters that
influence the geopolymerization process, which include type of alkali activators, alkali
activator concentration, curing temperature, liquid-solid (L/S) ratio and curing regime.
It was observed that a mixture of NaOH:Na2SiO3.5H20 at a ratio of 70:30 yields a better
geopolymer material. The concentration of 10 M NaOH:Na2SiO3.5H20 at a ratio of 70:30
was observed to be the best that yielded the UCS that is acceptable according to SANS1215 standards. When evaluating curing regime, it was found that the material cured
using greenhouse has lower UCS as compared to the material cured using oven. The
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effect of temperature showed that the UCS decreases with increasing curing
temperature. An admixture of river sand and cement was introduced which resulted in
a high UCS of 21.16 MPa when using an admixture of cement. The mineralogical
composition of the geopolymer bricks showed formation of secondary minerals such as
phlogopite, fluorapatite, diopside and actinolite. Batch leaching conducted on the
geopolymer bricks detected high leaching of Na from the bricks.
Based on the findings of the study of the raw MT potential to produce geopolymer
bricks, it was concluded that the material can be used to produce bricks that are within
the SANS 1215 requirements. The study further recommended that the study a focus
on using cylindrical moulds, other alkali activators and a mechanical mixer. It was also
recommended that the greenhouse be restructured to contain heat within the greenhouse
during the evening so as to allow constant temperature within / NRF
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Interaction of gold mine taillings leachates with soil and geochemical partitioning of toxic metal speciesNgoetjane, Pitsi Christopher 02 February 2016 (has links)
Department of Ecology and Resource Management / MENVSC
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Impacts of cage aquaculture on the farm dam ecosystem and its use as a multipurpose resource : implications for irrigationDu Plessis, D. 12 1900 (has links)
Thesis (MScAgric (Conservation Ecology and Entomology)--University of Stellenbosch, 2007. / Small farm dams (< 20 ha) in the Western Cape Province provide adequate water conditions for
intensive cage production of rainbow trout (Oncorhynchus mykiss). A major environmental concern of
cage aquaculture, however, is the high inputs of nutrients via commercial diets and the subsequent
eutrophication of the water source. Eutrophication can result in the degradation of the general water
quality (increasing pH levels, oxygen depletion, increased hydrogen sulphide and free ammonia) and
shifts in the phytoplankton structure (increased biomass, single species dominance). Deterioration of
water quality will affect the success of the fish farming enterprise as well as the performance of
irrigation equipment by increasing the risk of clogging and corrosion. Water quality, phytoplankton and
zooplankton compositions were monitored at four sites from June 2005 to November 2006 to
determine the effects of cage culture on the farm dam environment, its associated biota as well as
irrigation water quality. The distribution of nutrients, nitrogen and phosphorus, was mainly influenced
by the stratification and mixing regime of the water bodies. Nutrient concentrations increased during
the winter mixing period while in the summer months, they seem to settle to the lower part of the water
column. Nutrient concentrations of production sites and reference sites were comparable except for
the ammonia levels that were significantly higher at the production sites. Phytoplankton corresponded
with nutrient availability resulting in high biomass during winter. In terms of biomass, phytoplankton
was approximately two times more abundant in production sites compared to reference sites.
Assemblage dominance by cyanophytes (Anabaena circinalis, Microcystis spp.) was found more often
in production sites, while reference sites were dominated by dinophytes (Ceratium hirundinella,
Peridinium spp.). Zooplankton biomass concurred with high phytoplankton biomass in winter.
Zooplankton assemblages in production sites sustained much higher biomass. Effects of cage culture
on irrigation water quality are evident from increased algal biomass and shifts in species composition.
These results indicated that at its present production level, cage culture had impacts on the farm dam
environment and irrigation water quality. The most significant evidence was given by increased
plankton biomass and single species dominance in production sites. However, these findings can not
solely be ascribed to the introduction of aquaculture as various other factors may also contribute to the
water quality of these ecosystems.
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