The hydrogeology of the Tono basin, Japan, is strongly inuenced by the hydraulic properties of faults, especially the main Tsukiyoshi fault, which extends through the centre of the assessment area and has an E-W strike. According to the results of borehole investigations, the fault has N800W strike, 700 dip, 10 ô 30m width and approximately 30m vertical off-set. Hydraulic head discontinuities over the main fault in the basin are about 40 m as a result of the low permeability of the fault acting as a barrier to ow perpendicular to it. The fracture data from the Tono basin was analysed in order to establish a correlation between geologic/geometric attributes of a fracture and associated permeability of the interval that contains the fracture, if any. Pressure response transients to excavation of two shafts that are monitored at various boreholes within the study site show that proximity to a fault is a key attribute that determines the ability of the fracture to conduct water. The responses in boreholes that are close to the fault are vertically invariant, indicating a large vertical permeability. This is not the case in boreholes that are further from the main fault, where there is depth dependence in the pressure responses. Near the fault, the damage zone seems to be equilibrating the heads between otherwise unconnected aquifers. The Tsukiyoshi fault therefore acts as barrier to ow perpendicular to it but also acts as conduit to vertical ow and ow parallel to the fault. A three-dimensional model that simulates groundwater ow in the Tono basin is constructed in order to study the dynamic uid ow before and after it was disturbed by production and the excavation of the shafts. In the steady-state calculation, the model predicts that the hydraulic head at depth in boreholes near the fault is near the land surface. This condition indicates high vertical permeability in those boreholes. This thesis introduces a new approach of using pressure response data to do an inversion calculation for the effective porosity of the granite. Pressure response transients have been analysed using a numerical inversion procedure to estimate the specic storage of the granite. The specic storage was calculated using the pressure response data and ranged from 4:12 10ô7 to 8:93 10ô6mô1. These values of the specic storage were used to do a transport calculation in order to study the impact of the main fault on the transportation of hypothetical contaminants in the basin. Particle tracking was used to investigate and demonstrate the effects of the fault on path lines. The fault was found to have a strong inuence on the transportation of contaminants. The general trend of the transportation of the contaminants follows groundwater ow from the northern high elevations toward the southern low elevation. This shows that the contaminants are transported mainly by advection. However, this trend is interrupted by the Tsukiyoshi fault that blocks horizontal ow and sends water toward the surface. An interesting feature demonstrated by the model is that, within the fault core, no contaminants were found. The contaminants rise through the high-permeability damage zone and cross over the fault through the weathered granite. However, at depths where the water changes direction slowly because of the fault barrier to horizontal ow, the contaminants seem to be able to cross the fault. The explanation is that diffusion becomes the dominant mode of transport at the point where the water moves at slow velocities.

The Institute for Groundwater Studies (IGS) undertook a groundwater surface water interaction project under the funding of Water Research Commission starting July 2010. The Modder River was identified as an appropriate study area since it is located downstream of Krugersdrift Dam and has only been impacted by farming activities. This thesis aims at investigating the hydraulic parameters and flow characteristics of groundwater in the study area aquifer so as to have a preliminary picture of the groundwater systems of the site prior to the groundwater surface water interaction project takeoff. The field procedures were performed starting with site inspection, drilling, water level monitoring, pumping tests, tracer tests, and chemical sampling. Geological classification was performed during site inspection and drilling, while soil cover was analysed for texture analysis in the soil science laboratory. Water level monitoring was performed to study the groundwater fluctuations and flow directions with time. Constant rate tests were performed together with recovery tests to determine the transmissivity of the aquifer in the study area while point dilution tracer tests were done to determine the Darcy velocity of the section of maximum flow in the aquifer. In chemical analysis, micro and macro analysis were performed while tritium 3H, Deuterium 2H, and 18-Oxygen were analysed for in isotope analysis. Chemistry and isotope analysis were done to classify water in terms of its source, fate and age. From all boreholes, at the average depth of 8 meters, an alluvial material was obtained in between the top calcareous soil material and the bottom shale formation. The water level fluctuation trend was similar in all boreholes indicating possibilities of a common aquifer intercepted by all boreholes. Using water level time series, groundwater flow direction was determined to be towards the North-Eastern direction slightly in the direction of local topography while the river flow is westwards. The geometric mean of transmissivity values obtained from a Cooper-Jacob plot is 66 m2/d and the geometric mean for the recharge value from chloride method is 1.7 %. The geometric mean of the Darcy velocity value obtained from different boreholes in the aquifer is 6.9 m/d. These mean values are representative of the whole aquifer. In addition to flow direction being due to topography, it is hypothesized that the unusual flow direction behaviour is due to the seepage that acts like a natural borehole at the river bank such that a semi-cone of depression is formed towards the North East. In hydrochemistry, the most abundant cation is sodium followed by magnesium and the most abundant anion is T.Alk (carbonates). From a Piper diagram, groundwater was characterized to be calcium magnesium bicarbonate type of water. The SAR of groundwater is low and within the recommended value for irrigation agriculture while the EC is so high that the water is recommended strictly for crops that are not sensitive to brackish water. According to the isotope analysis, the water from the boreholes and seepage seem to have the same isotopic fingerprint. Needless to say that, the water that seeps on the banks is the same water as that from the aquifer that is intercepted by the boreholes. Groundwater plots closer to the global meteoric water line than river water which plots on the evaporation water line, needless to say that, river water is evaporation water rich in 18-oxygen while groundwater experiences less evaporation hence high 16-oxygen content. The hydrogeology of the area is therefore characterized by the presence of major flow in the gravel material at the average depth of 8 meters.

Fractures are mechanical ruptures in rocks, form by stress (lithostatic, tectonic, and thermal stresses and high fluid pressures) concentrations around flaws, heterogeneities, and physical discontinuities at a variety of scales. In groundwater reservoirs, mainly in those formed within relatively less permeable or hard rocks, connected fractures may form privileged conduits for fluid flow and solute through the rock, and therefore needs to be located and quantitatively (geometry, permeability, and ability to transport solute) appreciated for a better understanding of water flow and mass transport processes in the subsurface. Many techniques have been adapted from petroleum applications to address these issues and are reviewed in the present study with after an overview on geological and geo-mechanical features that evolve fracturing. Very few existing tools are cost-effective and easy to be performed on the field. The FEC (Fluid Electrical Conductivity) based techniques; mainly the single borehole based ones involve often, relatively cost effective equipments and are simple. The present study focus also on the applicability of âFlowing Fluid Electrical conductivity loggingâ (Tsang et al., 1990; Doughty et al., 2005) and the FEC based dilution test (well dilution) for fracture characterization in the Karoo aquifer. The FFEC is found to be a promising technique for local fracture characterization, mainly in contamination studies (investigation and scenario testing), like in mine environments; and is recommended to be experienced in South-Africa, particularly in the meta-sediments of the Karoo environment. The FEC based dilution test (well dilution) is gaining interest in fracture characterization in South Africa (Mohr Samuel and van Biljon Willem., 2009; Lasher Candice et al., 2009) and has been assessed on two experimental fields in the Karoo Aquifer. The technique is found to constitute a powerful tool for detection of flowing fractures and for qualitative interpretation. The Drost et al (1968) analytical solution suggested for the analysis of the test data (Cook et al., 2001a; Love et al., 2002) have been applied and yielded semi-quantitative values that can be used as first estimation of the groundwater velocity from flowing points into the studied boreholes. However, due to non ideal condition, refinements are still needed mainly for the field procedure and for the consideration of the mass circulation that may be associated with density gradient along the borehole.

The study describes the application complimentary geohydrologic tools to investigate the geohydrological properties of an alluvial channel aquifer and its interaction with the river surface water resources. Primary field investigations were designed to determine the geologic, hydraulic, hydrogeochemical and solute transport properties of the alluvial channel aquifer as an important component of the groundwaterâsurface water (GWâSW) interaction system. The secondary investigations were then aimed at assessing groundwater discharge and recharge mechanisms of the alluvial channel aquifer at a local scale (< 1000 m). A water balance model was developed for the groundwaterâsurface system as a tertiary level of investigation. Geological characterisation results show the spatial variation in the physical properties of unconsolidated aquifer materials between boreholes and at different depth. The drawdown derivative diagnostic analysis shows that the alluvial channel aquifer system response during pumping can be described by the following major groundwater flow characteristics; Typical Theis response; transition period from initial Theis response to radial acting flow (RAF); radial acting flow in the gravelâsand layer and river single impermeable boundary effects. Detailed studies of the hydrogeochemical processes in the alluvial aquifer system have shown that dissolution of silicate weathering, dolomite and calcite minerals, and ion exchanges are the dominant hydrogeochemical processes that controls groundwater quality. Quantitative and qualitative investigations indicate that the alluvial channel aquifer is being recharged through preferential infiltration recharge as facilitated by cavities and holes created by the burrowing animals and dense tree rooting system. Tracer tests under natural gradient were successfully conducted in an alluvial channel aquifer, thus providing some advice on how to conduct tracer breakthrough tests under natural gradients in a typical alluvial channel aquifer. The findings of the study also highlights the value of developing a water balance model as a preliminary requirement before detailed GWâSW interaction investigations can be conducted. Based on the theoretical conceptualizations and field evidence it is suggested that studies be conducted to determine if alluvial channel aquifers can be further classified based on the nature of the hosting river channel. The classification would split the alluvial channel aquifer into alluvial cover and fracturedâbedrock, or a combination of the two. The applications of the PhD thesis findings are not only limited to the case study site, but have important implications for GWâSW interaction studies, groundwater resource development and protection in areas where groundwater occurs in alluvial channel deposits.

Over the last 15 years the Windows Interpretation System for the Hydrogeologist (WISH) was developed by the author of this thesis. The program is used by numerous mines and consultants all over South Africa and abroad. WISH does not discriminate between mining types as it is just as capable of handling all water issues in the gold mines, platinum mines, iron mines or as the title of this thesis implies coal mines. Many other water related software packages are available. Most of them are developed for a single purpose. (Borehole logs, pumping tests, chemistry graphs or mapping) WISH is different because it can do it all. WISH was developed with the Hydrogeologist in mind. When a graph is requested WISH will create one first and subsequently allow the user to modify the graph. The volume calculations for opencast and underground mines are a breeze and no other existing software can do this with so much ease. Many collieries in South Africa are using WISH, not only for the chemistry and time data capabilities, but also for the management of large volumes of water. Many collieries trust WISH to calculate water capacity and water volumes in the mines. Decisions are taken to build 200 million rand water treatment plants. This thesis discusses the development and existence of WISH. A comparison with all other (ground) water related software available worldwide followed by a more in detail description of WISH and a quick starter guide on how to create a WISH document. A chapter is dedicated to recharge and decant followed by a discussion on how to use WISH in a real life project.

A new opencast coal mining operation is proposed in the Belfast region in Mpumalanga, South Africa. This proposed operation is the study site that was investigated in this thesis. The Belfast opencast operation is expected to be operational for 29 years and coal from mainly the number 2 and 3 seams will be mined. The inflow rate of the groundwater was determined by using both analytical and numerical groundwater methods. The rate at which groundwater flows into the mine voids are important to estimate before mining commence since this will determine at what rate groundwater needs to be pumped from the mining pits to ensure dry and safe working conditions. In order to obtain site specific data for the study area, several field investigations have been conducted. These investigations include a geophysical survey, drilling of monitoring boreholes and pump testing of the monitoring boreholes. These investigations are done to obtain a better overview of the aquifer conditions in the study area. For the study area a numerical groundwater flow model was constructed and the groundwater inflow was determined by making use of a water budget function. The analytical approach to determining the inflow included four different methods. A sensitivity analysis was done on the recharge with the numerical and analytical methods. The results from the numerical and analytical approaches were compared to determine whether the analytical approach is in fact a good way of obtaining values that relates with the numerically obtained results. If there is a good correspondence between the analytical and numerical results, the analytical approach can be regarded as a save and representative way to obtain groundwater related values. Especially during the early stages of mine planning analytical methods would be supportive to quickly determine mine related issues as this will assist in decision making and related cost estimates. From the results obtained in this thesis it can be concluded that the analytical approaches used during this study, although giving close to numerical answers, cannot be used in an effective manner in determining groundwater inflows during the early planning of mining. The fact that the analytical approaches did not reveal representative values for the groundwater inflows and also do not correlate with the numerical model results, does not mean that this will be the case at another site with different geohydrological characteristics. It is important to note that assumptions are always made in analytical methods. It is suggested that further research be conducted in relation with analytical and numerical modelling of opencast mines. Research should be performed at several mines to determine whether the relation between the numerical and analytical approaches display similar trends than was found during this study. These mines should preferably be on similar geological areas to compare with each other. The only way to determine whether the analytical methods can in fact be used to get a representative result is by repetition on several mining sites and also comparing these values with the numerical model results and also the actual inflow rates from the mine once mining has started.

A key challenge for chromium related activities, such as in ferrochromium industries, is the disposal of waste containing chromium slag or dust with hexavalent chromium (Cr(VI)). Various investigations have shown that hexavalent chromium is a serious concern to both environment and human health because of its mobility and carcinogenicity (Fendorf et al.; 2003). This study evaluates the impact of chromium on groundwater in the unsaturated and saturated zone by human related activities. A South African ferrochromium industry sector based in the Mpumalanga Province, (Middelburg) was selected as a case study to assess a waste dump of ferrochromium slag. The challenges regarding the dumping of slag are the oxidation of trivalent chromium (Cr(III)) to hexavalent chromium, as well as fine dust from the open arc furnaces which contain hexavalent chromium. At the case study site, the historic dump site (HDS), which is not lined, was previously used to dump various waste materials (since 1964), including but not limited to: ï· Ferrochromium slag ï· Phenols ï· Fine dust from open arc furnaces (with hexavalent chromium) ï· Filter cake (with hexavalent chromium) Literature studies indicate that trivalent chromium can be oxidised to hexavalent chromium Cr(VI) through presence of moisture, dissolved oxygen and manganese dioxide (MnO4) (EPA, 1994). The literature also indicates that concentration of hexavalent chromium Cr(VI) greater than 1 mg/l imparts a yellow colour (US EPA (1994) which was used as a visual indicator during field assessments at the HDS. The presence of hexavalent chromium was observed at the toe of the dumps and in low lying areas surrounding the dumps with elevated moisture contents. The presence of hexavalent chromium was also confirmed by monitoring results for both surface and groundwater. The mitigation that has taken place on site, involved the removal of hazardous waste such as fine dust and filter cake with hexavalent chromium from the HDS, and dumping it at a hazardous waste site (Holfontein). Other on-going mitigation at the dump is the usage of ferrous sulphate at the capturing point (infiltration gallery) to reduce hexavalent chromium to trivalent chromium through oxidation-reduction (redox) reaction process. This study has indicated that although some remedial approaches have been performed, the contamination still exists at the site. The findings of the study assessment have indicated the following: ï· Boreholes near the process plant indicated contamination by both trivalent chromium and hexavalent chromium. ï· Dam 4A and 4B have the highest concentration of hexavalent chromium as well as other constituents, such as sulphate (SO4). ï· Boreholes down-gradient of the HDS indicated pollution by hexavalent chromium, sulphate (SO4) and other parameters. ï· The western boreholes showed a trend of increasing pollution by sulphate (SO4), though not by trivalent or hexavalent chromium. Background boreholes did not show any pollution. ï· Contamination to the unsaturated zone is high but also differed when compared to contamination in saturated zones. ï· Contamination by hexavalent chromium is caused mainly by the fluctuating water table during water spraying (cooling) of hot slag, and due to precipitation in the rainy season.

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.

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