The purpose of the study is to investigate the influence of flooding on underground coal mines. Two case studies were investigated the shallow underground Klibarchan coal mine and the deep underground Usutu mine. Kilbarchan colliery is located 10 km south of Newcastle in KwaZulu/Natal. It comprises two underground sections, called Roy Point and Kilbarchan. Usutu colliery is situated just 8 km outside the town of Ermelo in Mpumalanga, close to Camden power station on the N2 road to Piet Retief. The geology of both studies lies within the Karoo Group, Ecca subgroup in the Vryheid formation. Higher precipitation at Usutu and Kilbarchan occurs in the summer months, while Kilbarchan has a higher annual rainfall of 864 mm/a compared to Usutuâs 705 mm/a. The water levels at both mines yielded interesting findings. Usutu mine is compartmentalized with walls in the underground. These walls are so strong that they function as âlow pressureâ seals resulting in compartmentalized underground, withstanding the huge pressures created by the recharged groundwater. This causes water levels to differ in the underground. Water levels at Kilbarchan mine vary in depth, but when plotted in metres above mean sea level (mamsl) they plot in a straight line. Regional recharge at Usutu was calculated as 5.7 % and 11.3 % at Kilbarchan. Recharge is influenced by what type of mining activity was practised in that specific area. It was concluded that recharge on opencast is between 15 to 20%, the stooped area between 10-15% and in an underground shallow mine it could be as high as 10%. Mining activity ceased in 1992 at Kilbarchan. Pumping is a common practice at flooded underground mines, because the mine needs to be filled with water on an ongoing basis. This prevents sulphate generation and the water quality from deteriorating. Pumping at Usutu is well managed and flushing started to occur in the underground with the electric conductivity improving over time. Pumping at Kilbarchan is poorly managed and over pumped. The electric conductivity over time, is not improving indicating that oxygen infiltrates the system when too much pumping occurs. Bord-and-pillar mining followed by stooping has been the main mining method. At Usutu mining activity ceased in the late 1980 and then the mine was flooded. It is finally there is concluded that an underground should be flooded as quickly as possible and then managed well. Shallow underground mines have a higher potential of contamination, because of a shorter residence time. The depth of mining, topography, mining methods, water levels, exposure to oxygen, rainfall, recharge, residence time and pumping have an influence on the effects of a flooded coal mine.

South Africa has several coal mines of which promised economic wealth since the 1700, however the exploitation of this commodity has a negative effect to the environment. Mining operations are a source of Acid Mine Drainage (AMD) in South Africa therefore salt loading and acidic conditions are of concern. Although lab methods such as Acid-Base Accounting (ABA) are used to predict the impact and effects of AMD, it is still difficult to predict its rate. The importance of laboratory analysis is to give the best and worst case scenario of the area, provided that the samples are representative of the area investigated. This thesis is conducted to note the difference between South African and Australian Laboratory methods in determining the potential and existing acidity of the samples. Furthermore, AMD is predicted using ABA methods for the Middelburg area. South Africa uses similar ABA laboratory guidelines as USA and Europe while Australia uses its own guidelines that are modified from time to time. After the comparisons of the methods were evaluated, the Australiaâs versus the South African results showed a very good correlation. However the Ca percentage from the ICP results had a lower correlation compared to other cations in the Actual Acidity Method. The KCl and NaOH used in the Australian Actual Acidity Method either displays the Ca as double or half of the South African ICP results. However, both countriesâ Actual and Potential Acidity Methods are comparable. The Australiaâs Neutralising Potential Method is derived from lime analysis disciples and can be an overestimate of the Neutralising Capacity. Whether the methods and results of Neutralising Capacity can be compared or not, is inconclusive. Other ABA tests have to be done on the same samples to verify if personal, analytical or instrumental error was significant. To achieve another aim of this thesis, The IGS was approached by Middelburg mine services to update the 2006 groundwater model at Goedehoop, Hartebeesfontein, Bankfontein and Klipfontein Collieries. At a later stage, Acid-Base Accounting (ABA) methods were requested for AMD prediction. The aim of the project was to do groundwater assessment of the collieries and predict future impacts of AMD. The locality of the investigated area is in the Middelburg, which falls in the central Highveld of the Mpumalanga province in South Africa. Open-cast coal mining is in operation at Klipfontein, Hartebeesfontein and Goedehoop. Klipfontein is along south of the Vaalbankspruit while Hartebeesfontein and Goedehoop spreads north of the Spookspruit. The area is in the Karoo Supergroup which underlines two thirds of the Republic of South Africa with typical rocks like sandstone, mudstone and shale. About 4.7 % of the representative samples from the Middelburg Collieries showed a Net Neutralizing Potential in the Static test method whereas Kinetic tests results proved that only a handful of the samples had a low salt load and a limited buffering capacity. In conclusion, the representative samples showed the investigated Middelburg Collieries had high-medium risk of acid-generation upon oxidation. With the prediction of AMD done, control measures can be put in place. The primary objective of AMD treatment is to remove metals (i.e. sulphides, hydroxides and carbonates) and raise the pH to alkalinity. Passive or Active treatments could be used to remedy the area. The deteriorated water quality caused by the coal mining area could be remediated and released into the Upper Olifants river catchment.

None

This thesis aims at geohydrologically assess arsenic in the Jagersfontein area and hence proposing remediation option. The field procedure carried out involved hydrocensus and sampling where samples were collected and analysed for micro and macro parameters with emphasis on arsenic. Isotopic (18O, D (deuterium) and Tritium 3H) analysis was also carried out to characterise the water in terms of its origin, fate and age. A total of 20 boreholes were sampled. Historical data from Bloemwater was also incorporated in the study. According to the chemical analysis, the most abundant cation is magnesium followed by calcium, and the most abundant anion is sulphate. Three different water types were classified; sodium/potassium sulphate, magnesium sulphate and calcium/magnesium bicarbonate. Hence they are from different sources. Sample collected from the mineshaft showed highest arsenic concentration which is higher than the South African National Standards (SANS 241, 2006) guideline for acceptable arsenic concentration in drinking water while all other individual boreholes in the main town of Jagersfontein showed low arsenic concentration (<0.006 mg/l); hence concluding that arsenic contamination comes from the mine. Mine water that has been treated in package plant (JFinal) still shows high arsenic concentration. Water from Kalkfontein dam is being treated in a bigger treatment plant (went operational in July 2012) and mixed with treated mine water. This reduces the arsenic concentration of water to an acceptable level before it is finally supplied to the community. Spearmanâs correlation coefficient calculated show a weak correlation between arsenic and other chemical parameters and so it is concluded that arsenic and these elements are not of same source implying the source of arsenic is not geogenic. Isotopic analysis shows the water samples plot very close to the global meteoric water line (GMWL) implying the groundwater is meteoric and is derived from the atmosphere. Clustering of the samples around the GMWL hints they might be of the same age. However one sample (surface water sample) plotted away from GMWL and it is attributed to effects of evaporation. The hardness of the water samples is generally high. To solve this problem, individual owners of boreholes add water softeners (chlorine, crystals) to soften the water. There are several techniques available for removal of arsenic from water in large conventional treatment plants. The basic principles of these technologies are based on physical-chemical processes such as oxidation, coprecipitation and adsorption on coagulated flocs, adsorption onto sorptive media, ion exchange, and membrane filtration. Most treatment options need the oxidation of As(III) to As(V) for efficient removal of arsenic. For the case of Jagersfontein, coagulation and filtration technology (FeCl3 as coagulant) will be the best option because it is very efficient in removing arsenic (V) which happens to be the dominant specie in the water. It is the cheapest technique compared to the others and it is also less sophisticated. However what is currently done in Jagersfontein to reduce the concentration of arsenic in water is dilution/mixing. Mine water treated in a package is mixed with treated water from Kalkfontein dam. Water (not arsenic contaminated) from Kalkfontein dam is treated in a bigger treatment plant which went operational in July 2012.

Australasian, European, Canadian and American geo-environmental specialists have long been involved with pit lake studies in the physical processes and dynamics as well as the geochemical aspects of these mitigation methods and events. The use of pit flooding as an environmental post-closure option has however been studied and used to a limited extent in Southern Africa and Africa to a whole, with some recorded cases mostly being by accident rather than a planned mitigation. This document is a written paper on a hydrogeochemical investigation on the feasibility of flooding an open pit platinum mine in the Bushveld Igneous Complex as a post-closure mitigation option. Various data sets and sources were compiled and processed and served as input data into a hydrogeochemical model of the expected impacts on the conceptual meromictic pit lake environment. Weathering and speciation models allowed the evaluation of the current system with thermodynamic and chemical reaction processes leading to the hydrochemical composition of the groundwater as we observe it in the field. Furthermore transient mixing simulations between groundwater, surface water and rain water was allowed to occur under various reducing and evaporative conditions. The modelled lake chemistry was then evaluated against recreational, agricultural and domestic water use standards to investigate the feasibility of the lake to be used post-closure. Final recommendations and mitigation methods were proposed with the flooding of the open pit as a post-closure option declared feasible. A final deliverable of the study was a system thinking and modelling template for hydrogeochemical modelling in various scenarios to guide other scientist through the process of modelling fluid-rock, fluid-waste and fluid-fluid interaction.

The remediation of sites contaminated by dense non-aqueous phase liquids (DNAPLs) continues to present a significant environmental challenge globally. Contributing to this challenge is the difficulty in locating source zones due to local heterogeneities in the sub-surface. Heterogeneities are significant in fracture rock environments, such as those found in South Africa, which together with the fluid properties determine the fate and transport of DNAPLs. This research is based on evaluating the effectiveness of combining traditional and novel source zone characterisation methodologies in order to delineate chlorinated hydrocarbon DNAPLs in a fractured rock environment. The research documents and evaluates the characterisation process followed in the application of various methodologies to an Investigation Site in South Africa. A site-specific conceptual site model is presented indicating the delineation of the multiple chlorinated hydrocarbon DNAPL source zones at the site. Additionally, a DNAPL source characterisation approach is proposed for application in fractured rock environments. This approach allows for the convergence of traditional approaches (such as drilling within a fixed grid) with more novel approaches (such as high resolution sampling and analysis). The pioneering use of ribbon NAPL samplers (FLUTeTM activated carbon technology membranes) in South Africa is documented in this research. In situ source zone characterisation using this technology in a fractured rock environment is shown to be successful in determining depth discrete fracture transmissivities and residual DNAPL zones that would have gone unobserved through methods such as direct observation and testing rock cores with hydrophobic dyes. The efficiency of this technology renders it ideal for future continued use in South Africa.

Winter (1999) succinctly, made a profound statement to the effect that understanding the basic principles of the interaction between surface water and groundwater is needed for effective management of water resources. Hence, the research investigation was aimed at identifying appropriate methodologies for assessment of surface water â groundwater interaction, thus enhancing the understanding thereof. The methodology used entailed a review of national and international literature on related previous and current models, systems and methods used in assessment and quantification of water exchange between groundwater and surface water. This was then followed by relevant case study analyses where distinct areas where chosen based on availability of relevant data and information by previous investigators. The findings were that various methods and classification systems are widely available but the applicability thereof under the South African conditions depends on the conceptual understanding of the area or system under investigation, availability of data and the basic assumptions associated with the particular model or method. The surface water â groundwater interaction cannot easily be quantified with confidence without requisite data available. The other finding is that use of multiple techniques to reduce uncertainties and to confirm or verify the existence or nonâexistence of the interaction is essential. Preferably, at least one method should be utilised to trace flow or qualitatively establish the water exchange while the alternative method is used for quantitative estimation of the interaction between surface water and groundwater. Some of the products emerging from this research investigation include decision tables for choosing applicable analytical method, applicable numerical method and the framework for guiding the selection of appropriate methodologies for assessing or quantifying the interaction between surface water and groundwater. Knowledge generated is applicable to water resource management, resource protection, water allocation and monitoring.

The suitability of different electrodes arrays used during electrical resistivity tomography surveys for geohydrological studies in the Karoo rocks is evaluated through theoretical considerations, numerical modelling and field surveys. The theoretical considerations predict that the Wenner array is sensitive to vertical changes in resistivity in the subsurface, while the Dipole-Dipole array is sensitive to horizontal changes in resistivity and the Schlumberger array is sensitive to both vertical and horizontal changes in resistivity. The theoretical considerations also show that the arrays with the strongest signal strength, the greatest depth of investigation and the broadest horizontal data coverage are the Wenner, the Dipole-Dipole and the Pole-Pole arrays, respectively. Twenty synthetic geological models, simulating dolerite dyke and sill intrusions, weathered zones, faults zones or bedding plane fractures and different types of geological boundaries, are used to evaluate the sensitivity, depth of investigation, signal strength, as well as horizontal data coverage of the Wenner, Schlumberger, Dipole-Dipole and Pole-Pole arrays. Responses of these numerical models to the L1-norm, L2-norm and to random noise are also investigated. Numerical modelling results indicate that the Wenner array is sensitive to vertical changes in the Earthâs subsurface resistivity, has the strongest signal strength, yet the shallowest depth of investigation and the narrowest horizontal data coverage. The Schlumberger array, sensitive to both vertical and horizontal resistivity changes in the subsurface, has high signal-to-noise ratio and better depth coverage compared to the Wenner array. The Dipole-Dipole array is seen to be sensitive to horizontal resistivity changes in the subsurface, has great depth penetration, but a low signal-to-noise ratio. Although the Pole-Pole array has the broadest horizontal data coverage and the greatest depth of investigation this array is the most vulnerable to noise contamination. The robust constraint inversion (L1-norm) should be selected for inverse modelling if the goal of the surveys concerns groundwater exploration since this algorithm produces models with sharp boundaries between different geological bodies. Conversely, the smoothness-constrained least-squares inversion (L2-norm) is appropriate when studying groundwater migration and contaminant transport because the diffusion boundary of a contaminant plume in the subsurface geology is likely to be associated with a smoother variation in the resistivities. The L2-norm inversion method gives optimal results under such conditions where gradual changes in the subsurface resistivities are expected. Two-dimensional electrical resistivity tomography surveys were carried out at three different sites near the city of Bloemfontein where dolerite dyke and sill intrusions occur. Results showed that the Wenner array is the most suitable electrode array to use for field surveys conducted across sill intrusions, while the Schlumberger array is the most appropriate for field surveys over dyke intrusions or sills intruded by dykes. The Dipole-Dipole array presented significant limitations for the field investigations due to its low signal-to-noise ratio. Results from the field studies conducted around Bloemfontein are in agreement with theoretical considerations as well as numerical modelling except the minor limitation of the Dipole-Dipole array (array recommended in theory by some authors). Results demonstrate that the two-dimensional electrical resistivity tomography surveys employing either the Wenner or Schlumberger arrays, in conjunction with the appropriate inversion technique, would be of great benefit to geohydrological studies in Karoo rocks, particularly for boreholes siting and during contaminant transport studies.

This thesis is the first study in South Africa to explore the concept of logistics cities in peripheral areas with in the context of local economic development. Although the term logistics city is used freely to denote cities in which logistics forms an important part of their economic base â as is the case in Dubai, Shangai and Zaragoza â the body of academic literature on the topic is extremely limited. The logistics city concept was formulated in Australia as an academic concept from approximately 2006 onwards. In South Africa, there is seemingly a tendency among decision makers to regard the mere existence of an airport, especially its potential transformation into an air-freight hub, as a possible local economic development initiative. The aim of this study was to evaluate Upington (as a peripheral area within the South African economy) and its ability to utilise the Upington International Airport as a local economic development initiative, specifically from the perspective of a logistics city. The study analysed the latest theoretical developments in location theory, specifically the new economic geography (NEG) and cluster theory as a basis of the logistics city. The NEG, which was developed in the 1990s in response to the changes brought about by globalisation and the strides made in technology, argues that â theoretically at least â peripheral regions could grow through the development of logistic clusters at the location of an airport. In addition, given the current capacity problems at OR Tambo International Airport, the NEG should pave the way for the development of a logistics facility at the UIA, the more so from the perspective of the logistics city concept. The study confirmed that, in spite of the theoretical opportunities presented by the NEG, the logistics city concept and the incorporation of an air-freight hub in provincial policy and strategy documents, air-freight hub development is still fundamentally dependent on market conditions and that the existence of well-developed airport infrastructure alone is not sufficient reason for transforming a regional airport in a peripheral area into a logistics facility. The study further showed that despite the increasing range of local economic development (LED) research in South Africa, academic literature focusing on the relationship between air-freight transport, logistics and LED is virtually non-existent. Moreover, the study showed that LED efforts are seriously hampered by a number of issues, such as the lack of assimilation of the logistics and air-freight industries into local economic development policy and plans, a lack of capacity at the institutional level, the lack of integrated planning between the spheres of government, the LED stakeholders, parastatals, agencies and the private sector and also the lack of clear policies on the developmental role of regional airports in South Africa. The dominance of ACSA, and the companyâs own lack of a strategic focus on regional airports, has also been shown to be problematic. The study further demonstrated efficient logistics to be an important determinant of a countryâs competitiveness and that South Africa may lose competiveness because both of high logistics costs and low logistics performance levels. The study also showed that there is generally a lack of accurate information and data on logistics and air freight in South Africa, particularly at the regional and the local level, which makes effective and integrated planning even more difficult.

Although naturally occurring in groundwater, nitrate presence is generally attributed and regarded as a contaminant. Elevated nitrate levels pose a threat once converted to nitrite, causing methaemoglobinaemia. This investigation serves to establish the origin, quantify the extent, distribution, and elucidate possible amelioration methods of nitrate in ground and surface waters of a chrome mine in Kroondal, South Africa. Already existing surface water and borehole (groundwater) points were sampled and monitored from 2011 to 2012. An independant sample collection was conducted twice during the year of 2012. ICP and isotope (hydrogen, oxygen and nitrogen) analysis were employed to see nitrate level behaviour. In 2011 and 2012, nitrate level elevations varied from acceptable to unacceptable, with maximums of up to 81.51 mg/l in both ground and surface waters (well above the Department of Water Affairs and Forestry domestic requirements of 10 mg/l). Hydrofacies plots attribute water chemistry to: calcium/magnesium bicarbonate, opencast mine, low sodium high salt and unpolluted waters. Domination in Mg cations occurs as would be expected within Bushveld Igneous Complex aquifers. This is a result of the abundance within mafic and ultramafic igneous rocks. Increased Nitrate concentrations in surface waters are suspected to be primarily a result of runoff from waste rock dumps, high in nitrate explosive residues. In groundwater, increased concentrations are suspected to be primarily a result of high nitrate concentrations in explosive residues from underground blasting, highly mobilised once in contact with water. A secondary cause is seepage from the tailings dam, waste rock, as well as from surface water, high in nitrate concentrations. Possible remediation strategies identified include Reverse Osmosis, Eco-Dosing and Biological De-Nitrification.