Showing items 1 - 19 of 19

Your selections:

Modelling of abandoned mine flooding - water quality and treatment requirement over time

- Huberts, R

Bottom ash and fly ash wastes as alkalinising reagents for neutralising acid mine drainage

- Ekolu, Stephen O., Diop, Souleymane, Azene, Firehiwot

  • Authors: Ekolu, Stephen O. , Diop, Souleymane , Azene, Firehiwot
  • Date: 2012
  • Subjects: Acid mine drainage , Bottom ash , Fly ash , Coal ash
  • Type: Book chapter
  • Identifier: http://ujcontent.uj.ac.za8080/10210/370290 , uj:5024 , http://hdl.handle.net/10210/13461
  • Description: Preliminary investigation was conducted to evaluate the utilization of bottom ash and fly ash by-products on a study limited to their role as alkalizing reagents, with the ultimate objective of examining their potential use for insitu treatment of acid mine drainage (AMD) in South African mines. Bottom ash (BA) and fly ash (FA) obtained from a coal-powered electricity generation station were used in varied combined proportions of 100/0, 90/10, 70/30 BA:FA reagent mixtures and used to conduct neutralization tests done at mix proportions varied from 20:1 to 1:1 AMD to reagent mixtures. Three types of acid mine drainage water from an underground gold mine (AMD-Wz), gold tailings dam (AMD-Lc) and a coal mine (AMD-MpK) were used in the investigation. Water quality tests were carried out before and after the neutralisation treatment. It was found that both bottom ash and fly ash are effective alkalinising reagents for neutralising AMD. The materials were found to be most effective when mixed at a ratio no greater than 5:1 of mine water to reagent. Use of the coal ash wastes effectively removed up to 99% of iron from the AMD. The sulphate concentration was also reduced by the treatment but it remained fairly elevated. Manganese concentration reduced as the pH of the treated water increased, reaching a negliglible concentration of < 1.0 mg/l at pH ≥ 11. Further investigations are underway to examine leaching and weathering characteristics of the reagents.
  • Full Text:

Modeling approach - Flowchart for an in-situ Acid Mine Drainage neutralization

- Basika, Batshiku, Huberts, Robert

Disintegration of concrete construction induced by acid mine drainage attack

- Ekolu, S.O., Diop, S., Azene, F.

  • Authors: Ekolu, S.O. , Diop, S. , Azene, F.
  • Date: 2016
  • Subjects: Acid mine drainage , Gypsum , Acid attack
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/214013 , uj:21225 , Citation: Ekolu, S.O., Diop, S & Azene, F. 2016. Disintegration of concrete construction induced by acid mine drainage attack.
  • Description: Abstract: In this paper, microanalytical investigation was conducted on disintegrated field concrete that had been used to construct a weir within a coal mine in South Africa. The concrete was in contact with polluted mine water, commonly referred to as acid mine drainage (AMD). Accordingly, the concrete weir had been exposed to dynamic conditions associated with flowing AMD. Investigations were conducted by optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometry (EDX), and X-ray diffraction (XRD). The field concrete samples examined consisted of soft broken concrete chunks and whitish powdery substance that had crystallized and formed a surface coating on the widely cracked locations of the deteriorated concrete. No evidence of sulphate attack or pyrite oxidation was found in the investigation; acid attack mechanism was diagnosed.
  • Full Text:

The use of bioassays to assess the toxicity of sediment in an acid mine drainage impacted river in Gauteng (South Africa)

- Singh, P., Nel, A., Durand, J. F.

  • Authors: Singh, P. , Nel, A. , Durand, J. F.
  • Date: 2017
  • Subjects: Acid mine drainage , Sediment toxicity , Bioassay
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/251795 , uj:26232 , Citation: Singh, P., Nel, A. & Durand, J. F. 2017. The use of bioassays to assess the toxicity of sediment in an acid mine drainage impacted river in Gauteng (South Africa).
  • Description: Abstract: Sediment contamination may occur from various anthropogenic activities, such as mining-, agricultural- and industrial practices. Many of the contaminants arising from these activities enter the aquatic system and precipitate from the surrounding water, becoming bound to sediment particles. These bound contaminants may reach concentrations higher than in the overlying water. Although water quality may be acceptable, an aquatic system may still be at risk if the contaminated sediment were to be disturbed through flooding, bioturbation or changes in the water chemistry. These contaminants may then desorb into the water column and prove detrimental to life forms in contact and dependent on that water source. Sediment quality monitoring has been a widespread international initiative and has led to the development of sediment toxicity assessment methods. This study focused on sediment bioassays, namely, Phytotoxkit, Ostracodtoxkit F and the Diptera bioassay, in assessing sediment quality of the Tweelopiespruit-Rietspruit-Bloubankspruit river system in Gauteng, South Africa. This river is known to have been impacted by acid mine drainage (AMD) since late August, 2002. Exposure of river sediment from 7 sampling sites to these bioassays provided an eco-toxicological estimation of the acute toxicity and chronic toxicity emanating from the contaminated sediments. Physico-chemical analyses revealed higher levels of sediment contamination closer to the mine. The bioassays displayed a similar trend with greater sensitivities to sediments closer to the mine and lower sensitivities to the less contaminated sites further downstream. AMD was therefore the main driver for sediment contamination. Whilst not all contaminants were bioavailable, statistical analysis showed that there were significant correlations between the elevated contaminant concentrations closer to the mine and bioassay responses.
  • Full Text:

Re-mining Johannesburg: urban redevelopment through the treatment of acid mine drainage

- Coetser, Dirk Andre

Chemical alterations in three clayey soils from percolation and interaction with acid mine drainage (AMD)

- Agbenyeku, Emem-Obong Emmanuel, Muzenda, Edison, Msibi, Mandla Innocent

  • Authors: Agbenyeku, Emem-Obong Emmanuel , Muzenda, Edison , Msibi, Mandla Innocent
  • Date: 2016
  • Subjects: Acid mine drainage , Subtropical clayey soils , Contaminant migration
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/212627 , uj:21000 , Citation: Agbenyeku, E., Muzenda, E & Msibi, M. 2016. Chemical alterations in three clayey soils from percolation and interaction with acid mine drainage (AMD).
  • Description: Abstract: The issues of acid mine drainage (AMD) from mining activities is not a new phenomenon to the present day developing South Africa as well as in most developed countries around the globe. However, the persistent rise in environmental contamination in South Africa is drastically attracting massive concerns. Vital concerns of AMD in South Africa still remain the threat to soil, surface, subsurface and ground water reserves among others, which consequentially impact human and environmental health. This insistent challenge has given rise to the need for investigating the buffering efficacy of clayey mineral soils for use as natural contaminant barriers to contaminant species from AMD. Therefore, the study presented herein, was channeled towards assessing the chemical alterations in three clayey soils from permeation and interaction with AMD via successive protracted percolation up to 18-25 pore volume passage of AMD through the respective soil medium. The final hydraulic conductivity measured, ranged between 1.3 × 10-11 m/s and 1.5 × 10-11 m/s. The obtained pH, electrical conductivity and solute breakthrough curves indicated the soils had low acid-buffering efficacies. Chemical species such as Na, Co and SO42- were highly dissolved due to attack on the soil grains by AMD. Chemical species were also released from the soils including the dissolution of metals and desorption of chemical species from AMD attack. As such, the study revealed that the buffering efficacies of the respective tested clayey soils to AMD chemical contaminants were generally ineffective.
  • Full Text:

The environmental impact of the Robinson Deep mine residue deposit, Johannesburg

- Collister, Grant

  • Authors: Collister, Grant
  • Date: 2008-05-26T06:29:19Z
  • Subjects: Environmental impact of gold mines and mining , Acid mine drainage , Environmental impact analysis , Johannesburg (South Africa)
  • Type: Thesis
  • Identifier: uj:2223 , http://hdl.handle.net/10210/462
  • Description: The environmental impact of the Robinson Deep mine residue deposit in Johannesburg was assessed by evaluating the water chemistry and surface precipitates, thereby identifying the processes responsible for forming the contamination footprint. Precipitates were compared to a documented paragenetic sequence of mineral formation associated with sulphide rich mine waste. PHREEQC, a geochemical modelling tool, was utilized to predict the formation of precipitates from evaporation ponds. The chemistry of the leachate was analysed and compared to water quality standards in order to determine the possible environmental impact. The chemistry of the water emanating from the mine residue deposit reveals that an Fe-SO4 dominant chemistry persists, this is consistent with acid mine drainage environments. The most toxic cations and anions contained in the water are Fe, Al, Mn, Ca, As, Mg, Cu, Zn, Pb and SO . It is predicted that the impact of toxic metals identified in the water decreases further from the mine residue deposit due to dilution and co-precipitation with different mineral phases such as goethite. Precipitates identified include jarosite group minerals, goethite, melanterite, copiapite, Mg-copiapite, halotrichite, pickeringite, gypsum and alunogen. These secondary minerals may be used as indicator minerals of acid mine drainage. Assessment and prediction of the stage of contamination and possible environmental impact, may, therefore be pursued when comparing the indicator minerals to predicted paragenetic sequences. For example, the precipitation of melanterite is consistent with an early stage of acid mine drainage development. The presence of melanterite thus suggests that oxidation of sulphides is an ongoing process on the Robinson Deep mine residue deposit. Evaporation of water in the evaporation ponds aids in increasing the concentration, hence allowing the predominant precipitation of jarosite group minerals. Alternatively, rainfall dilutes the water allowing dissolution of minerals located on the banks of the evaporation ponds to predominate. This mechanism of precipitation and dissolution is seasonal; formation of precipitates predominates during the dry season, while dissolution is most prominent during the wet season. The development of hardpans indicates that the main mechanism of formation of the associated phases is through capillary action at the sediment surface. Leaching of Fe2+-rich water from the mine residue deposit containment area is indicated by the presence of copiapite, while jarosite and goethite formation tend to form part of a hardpan layer. Goethite is an indication of a late stage mineral predominant at lower sulphate and higher pH conditions. Results of predicted formation of precipitates by PHREEQC are not in very good agreement with actual field observations. This is mainly due to the lack of thermodynamic data for many of the sulphate minerals observed. Hence, precipitates associated with acid mine drainage may be utilized as indicator minerals. Consequently, there identification may facilitate in environmental monitoring and risk assessment. , Prof. J. M. Huizenga Prof. J. Gutzmer
  • Full Text:

Effect of attapulgite calcination on heavymetal adsorption from acid mine drainage

- Falayi, T., Ntuli, F.

  • Authors: Falayi, T. , Ntuli, F.
  • Date: 2014-09-11
  • Subjects: Acid mine drainage , Attapulgite , Calcination , Heavy metal removal
  • Type: Article
  • Identifier: uj:5114 , ISSN 0256-1115 , http://hdl.handle.net/10210/13949
  • Description: Attapulgite calcined at 973.15K was characterized and utilized as an adsorbent for the removal of heavy metals and neutralization of acid mine drainage (AMD) from a gold mine. Batch adsorption experiments were carried out using a thermostatic shaker. Activated attapulgite showed that it can neutralize AMD as it raised the pH from 2.6 to 7.3 after a residence time of 2 h. Metal ion removal after 2 h was 100% for Cu (II), 99.46% for Fe (II), 96.20% for Co (II), 86.92% for Ni (II) and 71.52% for Mn (II) using a 2.5% w/v activated attapulgite loading. The adsorption best fit the Langmuir isotherm; however, Cu (II), Co (II), and Fe (II) data fit the Freundlich isotherm as well. Calcination at 973.15 K resulted in the reduction of the equilibrium residence time from 4 to 2 h, solid loading reduction from 10 to 2.5% m/v and an increase in maximum adsorption capacity compared with unactivated attapulgite.
  • Full Text:

Removal of sulphates from acid mine drainage using barium and organically modified clay

- Moreroa, Mabatho

  • Authors: Moreroa, Mabatho
  • Date: 2015
  • Subjects: Acid mine drainage , Acid mine drainage - Purification , Sulfates - Absorption and adsorption , Water - Purification - Organic compounds removal
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/212962 , uj:21060
  • Description: Abstract: Attapulgite and Mozambican bentonite (MB) were modified by using barium chloride and ammonium cations such as hexadecyltrimethylammonium bromide (HDTMA) and trimethyldecylammonium bromide (TDTMA) to enhance the removal capacity of sulphates from acid mine drainage (AMD). Through the modification process the surface properties of the clays was rendered organophilic. Batch adsorption experiments of the modified clays were done in a thermostatic shaker at different temperatures, mass loading of adsorbent, and cation exchange capacity (CEC) percentages to investigate the sorption behaviour of sulphates from AMD. Characterization of the modified clay that gave the highest removal of sulphates was done using XRF, XRD, FTIR and SEM to investigate the chemical composition of the clay, removal mechanism and structural change of the clay as a result of sorption of sulphates. Attapulgite showed higher removal of sulphates (70.8%) when modified with BaCl2 than the other two surfactants. This maximum removal was achieved at 25oC and 10% w/v clay to AMD. The reaction fitted the Temkin adsorption isotherm and the second order kinetic model. Adsorption of sulphates on attapulgite was not dependent on temperature as the difference in recovery was not statistically significant when temperature was varied. The value of activation energy (23.7kJ/mol) showed that chemisorption was the dominant mechanism of sulphate removal. MB showed higher removal of sulphates (74.0%) when modified with TDTMA. The reaction was endothermic and fitted the Temkin isotherm model and the second order kinetic model. More sulphates were adsorbed at higher temperatures, suggesting that this was an endothermic reaction, which was supported by the positive value of enthalpy. The activation energy for this reaction (-124.8 kJ/mol) showed that physisorption was the dominant mechanism of sulphate removal. Characterization of both clays showed that the sulphates were removed by adsorption and that the modifiers were only adsorbed on the surface of the clay during the cation exchange process without destroying the crystalline structure of the clay. At high solid loading, more sulphates were adsorbed from the AMD sample by both clays. This implied that at higher solid loadings, there are more sites of adsorption and thus, the higher sulphate removal... , M.Tech. (Chemical Engineering)
  • Full Text:

A multi walled carbon nanotube screen printed electrode modified with recombinant protein PbrR for detection of lead

- Molatji, Thulaganyo

The remediation of heavy metal contaminated water in the Wonderfonteinspruit catchment area using algae and natural zeolite

- Diale, Palesa Promise

  • Authors: Diale, Palesa Promise
  • Date: 2012-06-05
  • Subjects: Acid mine drainage , Groundwater contamination , Natural zeolite
  • Type: Thesis
  • Identifier: uj:2449 , http://hdl.handle.net/10210/4907
  • Description: M. Tech. , Gold (Au) mining in South Africa resulted in vast volumes of hazardous waste being generated. Poor management of most of the tailings dams has resulted in the release of acid mine drainage, which caused stream water and soil contamination with their run-offs. The consequence of mine closure has not only been observed in large-scale land degradation, but also in widespread pollution of surface water and groundwater in the Wonderfonteinspruit Catchment Area (WCA). Thus, clean-up methods must be developed in order to remove heavy metals from contaminated water bodies in this area. The efficacy of algae, zeolite and zeolite functionalized with humic acid in reducing the concentration of the heavy metals iron (Fe3+), zinc (Zn2+), manganese (Mn2+) and nickel (Ni2+) to acceptable levels in WCA was investigated in this study. It is also envisaged that the heavy metals to be removed from contaminated water can be useful in various industries. A sampling exercise was undertaken with the aim of identifying the heavy metals that contaminate the water in the catchment, as well as identify the priority heavy metals for laboratory sorption tests. Batch experiments were conducted to study the adsorption behavior of natural zeolite clinoptilolite and algae Desmodesmus sp. with respect to Fe3+, Mn2+, Ni2+, and Zn2+. The data was analysed using the Langmuir and Freundlich isotherms. Two kinetic models namely, pseudo-first order and pseudo second order were also tested to fit the data. It was found that the concentration of Fe3+, Mn2+, Ni2+ and Zn2+ was 115 mg/L, 121 mg/L, 26.5 mg/L and 6.9 mg/L from the sampled water bodies in the WCA, respectively. The Langmuir isotherm was found to correlate the adsorption of Fe3+, Mn2+, Ni2+, and Zn2+ better, with the adsorption capacity of 11.9 mg/g, 1.2 mg/g, 1.3 mg/g, and 14.7 mg/g, for the functionalized zeolite (FZ), respectively. The algae system gave adsorption capacities of 1.523 mg/g, 144 mg/g and 71.94 mg/g for Fe3+, Mn2+ and Ni2+; respectively. Pseudo second-order equation was found to be the best fit for the adsorption of heavy metals by unfunctionalized zeolite (UFZ) and the algae system. Zeolite functionalization with humic acid increased its uptake ability. The best results for kinetic study was obtained in concentration 120 ppm for Fe3+ and Mn2+, whilst for Ni2+ was at 20 mg/L , which is about the same concentrations found in contaminated water in the WCA (Fe3+ 115 mg/L, Mn2+121 mg/L and Ni2+ 26.5 mg/L).
  • Full Text:

A long-term acid mine drainage water management strategy for South Witbank Colliery, Mpumalanga

- Janse van Rensburg, Renee

  • Authors: Janse van Rensburg, Renee
  • Date: 2009-02-05T07:07:54Z
  • Subjects: Acid mine drainage , Witbank (South Africa)
  • Type: Thesis
  • Identifier: uj:14873 , http://hdl.handle.net/10210/1993
  • Description: M.Sc. , Water is essential to life on our planet (Miller, 1999) because no living organism can survive without it (Kupchella & Hyland, 1993). Thus there is a demand for clean, unpolluted water to be in substantial supply. There is growing awareness worldwide of the environmental legacy of coal mining activities that have been undertaken with little concern for the environment (EMCBC, 2001). Coal mining by its nature consumes, diverts and can seriously pollute water resources (Miller, 1999). Acid mine drainage is a major problem on coalmines throughout the world (Kupchella & Hyland, 1993), and South Witbank Colliery, the main focus of this study, is no exception. Various studies that have been undertaken at South Witbank Colliery have shown that the water decanting from the mine is highly acidic (pH 2 – pH 4), and as such cannot be released into the natural watercourse (streams). Some form of water treatment to nullify or neutralise the acid levels of the mine water is necessary. Currently a temporary liming plant is being utilised to treat the water and to reduce its acidity levels to between pH 5.0 – pH 9.5, however, this plant is seen as a limited treatment option as it does not guarantee that the acidic nature of the water will be sufficiently nullified. This study endeavours to identify and analyse a variety of permanent, long-term water treatment methods relevant to acid mine water mitigation at South Witbank Colliery. Four long-term water treatment methods, namely artificial wetlands, anoxic limestone drains, transfer of water to a water treatment plant, and construction of a permanent liming facility at South Witbank Colliery, were identified and discussed. Artificial wetland technology has not been proven for treatment on such variable pollutant loads as present in the South Witbank Colliery mine water decant. A constraint to this technology also lies in its necessity for large surface area requirements, which is restricted due to site subsidence and sinkhole formation (as a result of shallow mining). This technology is also known to increase water evaporation rates, which may result in additional water removal from an already stressed resource. The anoxic limestone drain water treatment technology is considered unsuitable for the study area, ultimately due to it having more a pre-treatment functionality than a total treatment one. It is also limited due to its ability to address only certain water quality variables. If considered for use in a partnership with other acid mine drainage water treatment technologies, its use might be more viable than when considered as a stand-alone treatment technology. Transferring of the acid mine drainage water decant from South Witbank Colliery to a water treatment plant is a feasible option. The Brugspruit Water Pollution Control Works, operated by the Department of Water Affairs and Forestry, is the most likely option. The water treatment would become the responsibility of DWAF, thereby ensuring that the treated water is compliant with specified water quality standards and requirements. The attractiveness of this option is that it minimizes the short and long term water management requirements for South Witbank Colliery, but is ultimately dependant on a formal contract being negotiated between the relevant parties. Construction of a permanent liming facility at South Witbank Colliery is possible and, in comparison to the current temporary liming plant, is likely to treat the water adequately so as to comply with specified water quality standards and requirements. A permanent facility would allow for more water to be treated than is currently possible at the temporary liming plant. Due to this option being based on proven technology increases its feasibility in terms of use at South Witbank Colliery. Given that water is a scarce resource in South Africa, the implementation of these water treatment options is dependent on the acceptability of each option by the Department of Water Affairs and Forestry. Of the four treatment options identified the latter two, namely transfer of water to a water treatment facility and construction of a permanent liming plant, are considered to be the most suitable solutions for the treatment of acid mine drainage at South Witbank Colliery.
  • Full Text:

Treatment of acid mine drainage using un-activated bentonite and limestone

- Nkonyane, Thembelihle, Ntuli, Freeman, Muzenda, Edison

Use of desilicated fly ash as an adsorbent for heavy metals in acid mine drainage

- Falayi, T., Ngobeni, V., Ntuli, F.

  • Authors: Falayi, T. , Ngobeni, V. , Ntuli, F.
  • Date: 2015-04-19
  • Subjects: Desilicated fly ash , Adsorption , Acid mine drainage
  • Type: Thesis
  • Identifier: uj:5108 , ISBN 978-988-19988-9-7 , http://hdl.handle.net/10210/13932
  • Description: Desilicated fly ash (DFA), the residue from leaching of silica from fly ash, was used as an adsorbent for metals from acid mine drainage (AMD). DFA was found to be an impure phillipsite K zeolite. Batch adsorption experiments were carried out using a thermoshaker. A 0.6% m/v solid loading of DFA removed over 95% of Mn, Al and Cu from AMD. The adsorption process followed the Langmuir adsorption isotherm model and pseudo second order kinetics. The maximum adsorption capacities for Mn, Al and Cu were 14.3, 7.1 and 7.6 mg/g respectively at 25°C. The adsorption of Mn, Al and Cu onto DFA was found to be endothermic and with a positive entropy energy. The Gibbs free energy for the adsorption was found to be -1.7, -7.0 and -11.2 kJ/mol for Mn, Al and Cu. The preference for adsorption was found to be Cu>Al>Mn.
  • Full Text: false

To study the mobility of the naturally occurring radioactive materials (NORMs) in the sediments as a function of changing environmental conditions

- Shongwe, Nkosinathi Sipho

Quality of water recovered by treating acid mine drainage using pervious concrete adsorbent

- Shabalala, A. N., Ekolu, S. O.

  • Authors: Shabalala, A. N. , Ekolu, S. O.
  • Date: 2019
  • Subjects: Pervious concrete , Zero - valent iron , Acid mine drainage
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/404909 , uj:33978 , Citation: Shabalala, A.N., Ekolu, S.O. 2019 : Quality of water recovered by treating acid mine drainage using pervious concrete adsorbent.
  • Description: Abstract : In this paper, a batch experiment was conducted to evaluate the water quality obtained from using pervious concrete (PERVC) technology to treat acid mine drainage (AMD). The study proposes an innovative application of PERVC as a permeable reactive barrier liner in evaporation ponds. The effectiveness of PERVC adsorbent in removing heavy metals was compared with that of zero-valent iron (ZVI) of particles sizes 1.0 to 1.8 mm. The AMD used in the study was obtained from abandoned gold and coal mines. PERVC mixtures consisted of granite aggregate and ordinary portland cement CEM I 52.5R (CEM I) or CEM I containing Class F 30% fly ash (30%FA) as a cement replacement material. ZVI was prepared from a mixture of silica sand and iron grit of specific sizes. PERVC and ZVI media were used to conduct batch reactor tests with AMD, for a period of 43 days at a ratio of one litre of reactive material to three litres of AMD. The quality of treated AMD was compared against effluent discharge standards. The contaminants Al, Fe and Zn were effectively removed by both PERVC and ZVI. Also, both adsorbents reduced Ni, Co and Cu to levels below those measured in raw AMD. However, PERVC was more effective in removing Mn and Mg while ZVI was ineffective. Although PERVC removed more heavy metals and with greater efficiency than ZVI, the PERVC – treated water showed high pH levels and exhibited elevated Cr6+ concentrations, owing to leaching from the cement and fly ash materials used in PERVC mixtures.
  • Full Text:

Assessment of the suitability of mine water treated with pervious concrete for irrigation use

- Shabalala, Ayanda N., Ekolu, Stephen O.

  • Authors: Shabalala, Ayanda N. , Ekolu, Stephen O.
  • Date: 2019
  • Subjects: Acid mine drainage , Irrigation , Pervious concrete
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/404921 , uj:33979 , Citation: Shabalala, A.N., Ekolu, S.O. 2019 : Assessment of the suitability of mine water treated with pervious concrete for irrigation use.
  • Description: Abstract : In water scarce countries, the treatment and re-use of polluted mine water can be a solution to the water shortage problem. In this study, the possible use of pervious concrete to treat Acid Mine Drainage (AMD) for irrigation of agricultural crops, was investigated. Pervious concrete mixtures consisting of 6.7 mm granite aggregate and plain portland cement CEM I 52.5R (CEM I) with or without 30% fly ash (30%FA) were prepared and used to conduct column studies on AMD. The AMD types used in the study were obtained from abandoned coal (TDB) and gold (WZ) mines. Physico-chemical parameters of water including the pH, electrical conductivity (EC), Total Dissolved Solids (TDS), along with element concentrations were analysed. Also the Sodium Adsorption Ratio (SAR), Soluble Sodium Percentage (SSP), and Kelly’s ratio (KR) of the treated AMD were calculated and compared against the water quality criteria for irrigation use. Results showed that heavy metal concentrations in the treated TDB or WZ were generally reduced to satisfactory levels for crop irrigation. The treatment of AMD using pervious concrete had no significant influence on TDS, EC, SSP and KR values. Use of CEM I pervious concrete increased the Cr6+ concentrations to levels above the limits acceptable for irrigation water but use of 30% FA in the concrete reduced the Cr6+ levels to permissible limits. Pervious concrete was found to be more suited for treating AMD sources of low alkali concentrations such WZ, to produce treated water quality for irrigation use.
  • Full Text:

Effect of regional geology and mining activity on water quality : studies in the eMalahleni (Witbank) and South Rand coalfields

- Mgoqi, Aviwe

  • Authors: Mgoqi, Aviwe
  • Date: 2019
  • Subjects: Acid mine drainage , Mining geology , Acid mine drainage - Environmental aspects - South Africa , Mine water - Environmental aspects - South Africa , Mines and mineral resources - Environmental aspects
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/401340 , uj:33536
  • Description: Abstract : Acidic drainage generated in mining environments has been a major concern for many years, especially since the acidic drainage leads to the deterioration of quality in water resources. South Africa is a waterscarce country, and solutions to try and counteract the spread of acidic drainage in mining environments are of major importance. Prediction of the potential for constituents to generate or neutralise acidity produced has become an integral part of the treatment and mitigation process employed in numerous industries. The use of modern methods in the determination of acid generation and neutralisation potential in earth moving environments is critical in the improvement of mitigation and treatment methods. Methods are frequently generated in order to improve on existing methods, assist existing methods, or change the way existing methods operate. In the process of creating new methods, complications are often encountered, leading to an extended time period in the creation process. The current method focuses on the analyses of acid-generating and acid-neutralising elements with the use of Inductively-Coupled Plasma Optical Emissions Spectrometry (ICP-OES). The method aims to assist in the prediction of acid generation/neutralisation potential of samples and improve the efficiency by reducing the period it takes for successful prediction to be carried out and analysing an array of minerals considered to be involved in acid generation and neutralisation reactions. Samples were subjected to nitric and hydrochloric acid as a means of leaching out sulphate and sulphide sulphur species, respectively. Subjecting the samples to acid also releases readily-dissolving elements (likely to be involved in acid-neutralising reactions) and compounds into the leachate. The content of elements that are constituents of acid-producing minerals (Fe, S) are compared to elements that constitute acid-neutralising minerals (Ca, Mg, Na, K). A balance between the respective minerals allows for the determination of the acid-generating and acid-neutralising potential as part of Acid Base Accounting (ABA) procedures... , M.Sc. (Geology)
  • Full Text:
  • 1
  • Disclaimer
  • Privacy
  • Copyright
  • Contact