Danie Vermeulen's research while affiliated with University of the Free State and other places

Publications (33)

Article
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Unconventional oil and gas (UOG) extraction can augment energy supplies in countries with viable gas resources, but it risks damaging water resources. Water supply problems for fracking can also limit UOG extraction, especially in water-stressed regions. Regulations are one of the main tools used to minimize UOG extraction impacts on water resource...
Article
Full-text available
The Phalaborwa (Palabora) Igneous Complex (PIC), South Africa, has been mined for the last six decades for copper and phosphate, among others commodities. As a result, more than 4500 Mt. of mining wastes have been deposited in waste rock dumps (WRDs) and tailing impoundments. This study aims to investigate the potential of the PIC wastes (WRDs and...
Article
A detailed characterization of alkaline tailing ponds and waste rock dumps from Phalaborwa Igneous Complex (PIC) South Africa, has been accomplished. The study goes beyond the environmental characterization of mining wastes, offering the first insight towards the recycling of the wastes as alkaline reagent to neutralize acid industrial wastewater....
Chapter
Full-text available
Four groundwater vulnerability assessment methods were evaluated, compared and applied to assess the aquifer risk of the Dahomey Basin shallow groundwater system in Nigeria. The methods include the DRASTIC, PI, RTt and AVI. These methods are grouped into the travel time, physically based approach (AVI and RTt method) and the index-based method (DRA...
Chapter
Four groundwater vulnerability assessment methods were evaluated, compared and applied to assess the aquifer risk of the Dahomey Basin shallow groundwater system in Nigeria. The methods include the DRASTIC, PI, RTt and AVI. These methods are grouped into the travel time, physically based approach (AVI and RTt method) and the index-based method (DRA...
Article
Unconventional oil and gas (UOG) extraction using fracking can damage groundwater resources, a crucial resource in many countries. Protecting groundwater will become more urgent as climate change and population growth increase pressure on water demand, especially in water‐scarce countries. But despite the strategic importance of groundwater, it is...
Article
Full-text available
Despite technical advances, traditional large diameter hand-dug wells remain very important in remote and rural communities as a method for gaining access to groundwater for drinking, domestic and agricultural activities. This paper explores and discusses large diameter hand-dug wells in South Africa, with regard to their utilisation, research and...
Article
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Underground coal gasification (UCG) is the conversion of coal in situ into a usable synthetic gas. One of the major environmental concerns with UCG is the possibility of groundwater from the coal seam aquifer contaminating the shallow aquifers via hydraulic connections. The coal seam aquifers are usually confined aquifers but can have hydraulic con...
Article
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Underground coal gasification (UCG) is a chemical process that converts coal in situ into a gaseous product at elevated pressures and temperatures. UGC creates an underground cavity that may be partially filled with gas, ash, unburned coal, and other hydrocarbons. A water stratification assessment can help assess the diffusion effects within the un...
Article
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Underground coal gasification (UCG) is an unconventional mining method that converts coal in situ into a fuel gas that can be used for electricity generation. Residue products from UCG have the potential to leach into surrounding groundwaters. The geochemistry and leaching dynamics of these products are explored in this study. The products include...
Conference Paper
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Remediation of acid mine and industrial drainages has high costs involved due to the infrastructure, consumables and disposal of the waste produced by current water treat-ments. is study provides the rst insight into a novel neutralization process using rare earth-bearing carbonatite from a waste rock dump that generates a marketable by-product, ca...
Article
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The shallow groundwater of the multi-layered sedimentary basin aquifer of southwestern Nigeria was assessed based on its intrinsic vulnerability property. The vulnerability evaluation involves determining the protective cover and infiltration condition of the unsaturated zone in the basin. This was achieved using the PI (P stands for protective cov...
Article
Tuli Karoo transboundary aquifer (TBA) is shared between Botswana, South Africa and Zimbabwe in the Southern African Development Community (SADC) region. The TBA provides groundwater resources for various economic activities. Irrespective of the value offered by this TBA, there is very little research that has been conducted to improve understandin...
Article
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A study was conducted to assess the performance of the flow-through bailer groundwater sampling method against the conventional purge method based on the analysis of inorganic chemistry and total coliform parameters. Sampling was performed at three sites for a total of 43 monitoring wells. Samples were first collected by a bailer from inferred grou...
Article
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Geochemical modeling of heavy metals released from the activities of artisanal mining for gold exploitation was investigated in this study. Samples of mine water and sediment discharges were collected before and after treatment. Untreated discharge shows pollutant of arsenic, lead, cadmium and iron in water and sediment above the acceptable standar...
Conference Paper
Full-text available
The study investigates the petrology, weatherability status, geochemical characteristics as well as metals distribution within in situ chemical weathering derives soils located on the Basement Complex rocks of Southwestern Nigeria. The study involves detailed description and sampling of 2 lithological profiles each from the granite (P1), gneiss (P2...
Conference Paper
Full-text available
The environmental impact of industrial drainages on South Africa affects surface- and groundwater in a country already stricken by the extreme scarcity of water resources. Ba-Phalaborwa municipality of Limpopo province is a clear example of this environmental impact. There is an industrial area, with two mines and a fertilizer industry, allocated b...
Article
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This paper presents the theory and application of rainfall and travel time (RTt) vulnerability method. The method is applied on a shallow aquifer in the Dahomey Basin of south-western Nigeria with the results being compared to other established vulnerability assessment methods. The method follows the source pathway receptor concept of aquifer vulne...
Article
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This study presents the outcome of mapping the shallow aquifers of the eastern Dahomey Basin of southwestern Nigeria vulnerability studies. The basin is a coastal transboundary aquifer extending from eastern Ghana to southwestern Nigeria. The study aimed to examine the most suitable method for mapping the basin shallow aquifers by comparing the res...
Conference Paper
Full-text available
The Dahomey Basin is a transboundary sedimentary basin with its eastern half in south western Nigeria. The vulnerability assessment of the basin was carried out to ascertain the degree of the shallow unconfined aquifers sensitive to groundwater contamination through the investigations of the intrinsic properties of lithology over the unconfined aqu...
Article
An investigation was conducted to statistically compare the influence of non-purging and purging groundwater sampling methods on analysed inorganic chemistry parameters and calculated saturation indices. Groundwater samples were collected from 15 monitoring wells drilled in Karoo aquifers before and after purging for the comparative study. For the...
Article
Hydrogeochemical processes have an important influence on evolution of the groundwater chemistry and its quality. An investigation was conducted to assess the hydrogeochemical processes in a flooded underground coal mine located in a typical Karoo Basin of Southern Africa. The study utilises scatter plots, PHREEQC hydrogeochemical model and the exp...
Article
The study aims to identify and describe the dominant hydrogeochemical processes and their contribution to the overall groundwater quality of an aquifer situated in the vicinity of a mine process water dam. The study site is located in a typical Karoo Basin of Southern Africa. Groundwater samples were collected from a network of boreholes designed t...
Conference Paper
Site characterisation aims to obtain fundamental information needed to describe the subsurface flow pathways and distribution of contaminants in the aquifer. The study describes the application of various hydrogeological techniques as complimentary tools to characterise a fractured-rock aquifer contaminated with light non-aqueous phase liquids (LNA...
Article
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The semi-arid and arid regions occupy almost two-thirds of South Africa and fall in the winter and summer rainfall zones of the sub-continent. The annual rainfall patterns can be regarded as intermittent with a significant spatial variability due to the unique winter/summer synoptic systems manifesting over Southern Africa. Summer rainfall events i...
Article
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Rainfall events in semi-arid regions of South Africa are characteristically erratic in terms of depths and recurrence rates. Chemical assessment of cyclic rainwater has recognised 3 intervals, spaced over the hydrological cycle, reporting diverse hydrochemical compositions of rainwater in winter and summer rainfall regions. Winter rainwater is gene...
Article
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Hydrological responses of hillslopes have been observed in a number of small research catchments (1-2sq.km) throughout South Africa. Hydrometric observations, geophysical techniques and isotope sampling have been combined to define and quantify a range of hillslope responses in these catchments. These hillslope responses have been grouped into typi...
Article
Full-text available
It is predicted that vast volumes of impacted mine water will be produced by mining activities in the Mpumalanga coalfields of South Africa. Irrigation provides for a novel approach to the utilisation and disposal of mine water, under the correct conditions. The significance of these findings lies in the versatility of this irrigation. Communities...
Article
It is predicted that vast volumes of affected mine water will be produced by mining activities in the Mpumalanga coalfields of South Africa. The potential environmental impact of this excess water is of great concern in a water-scarce country like South Africa. Research over a period of more than 10 years has shown that this water can be used succe...
Chapter
It is predicted that vast volumes of impacted mine water will be produced by mining activities in the Mpumalanga coalfields of South Africa. The potential environmental impact of this excess water is of great concern in a water-scarce country like South Africa. Research over a period of more than 10 years has shown that this water can be used succe...
Article
Full-text available
Advances in hillslope hydrology have been numerous in the past four decades. However many of these advances have been highly site specific in nature, counterintuitive to a unifying theory linking processes across different spatial scales. Meaningful Prediction in Ungauged Basins (PUB) requires the understanding and observation of processes across a...
Article
From local and international experience, it is known that coal mining has a pronounced impact on surface and groundwater quality and quantity. The influx of water may be as low as 1% of rainfall for deep border and pillar mines with no subsidence, to as much as 20% for some opencast mines (Hodgson et al. 2007). Such differences have significant imp...

Citations

... A CI platform is a technological system that uses public and institutional data to address environmental management problems such as the regulation of UOG extraction and is an ideal tool to serve as an interface between science, society and policy. Since South Africa is highly dependent on groundwater, our study focused on the development of a CI platform to properly enforce fracking regulations to protect groundwater resources [22]. ...
... Secondary sources of REEs include their recovery from waste, including electronic or electrical waste, mine tailings, contaminated residuals from mine drainage treatment, red mud, and phosphogypsum [10,[18][19][20][21][22][23]. Phosphogypsum (PG), originating from the digestion of phosphate rocks, contains up to 0.40% REEs. ...
... AMD formation is typical in tailings wherein the acid generation potentials, i.e., the sulfide contents (primarily pyrite), exceed the acid neutralizing capacities, i.e., the carbonate contents (e.g., calcite and dolomite). Neutral drainage is generally observed at sites where the acid neutralizing capacity associated with the carbonate mineral content is greater than the acid generation potential associated with the sulfide content [Gaskova and Bortnikova, 2007;Gomez-Arias et al., 2021;Nordstrom et al., 2015]. The mobilities and concentrations of metals in neutral solutions (pH 6-9) are significantly lower [Conesa et al., 2008;Da Pelo et al., 2009] while metalloids such as As, Sb, and Se remain mobile in neutral, subalkaline, and alkaline conditions [Ashley et al., 2003;Das et al., 2015;Hiller et al., 2012]. ...
... The AVI (Aquifer Vulnerability Index) method [14] was developed a few years after DRASTIC, utilizes the potential offered by GIS systems, and has also been widely used because it has the advantage of using only two physical parameters. Comparisons between these two methods [10,[15][16][17][18][19][20] demonstrate that both AVI and DRASTIC are suitable for predicting the pollution potential for porous aquifers. The AVI method tends towards higher vulnerability outcomes than DRASTIC, especially in shallow aquifers [21]. ...
... Many states in the US and Canada, where UOG resources have been extracted the longest, have extensive regulations to protect water resources. These regulations are however often a patchwork-with some being specific and prescriptive, and others vague and general 11,12 . It is, therefore, crucial to develop and enforce suitable regulations to protect water resources. ...
... Hand-dug wells are the most common traditional methods of obtaining groundwater in many developing countries. In rural communities, where the local hydrogeological conditions are favourable, many household water needed for drinking, cooking and irrigation are supplied by hand-dug wells (Aina and Oshunrinade 2016;Bruni and Spuhler 2018;Gomo et al. 2019;Schram and Wampler 2018;Mace 1994;Pickford 1990;WaterAid 2008). ...
... Where N is the normality, V (mL) is the volume, W (g) is the sample weight, and NP (kg) is the amount of calcium carbonate required or sulfuric acid produced per ton of mine tailings. The net neutralization potential (NNP) was then calculated by subtracting the acid potential (AP) from the neutralization potential (NP) according to Eq. (3) [30,32,33]. ...
... Physical changes in rock condition after thermal load are very visible from the change in color to darker burning until it becomes brighter and rock structures that become cracks [16,25]. Based on its resistance to heat, sandstone is a rock that is more resistant to heat compared to siltstone and claystone, this is not only caused by the condition of mass density, the porosity of the rock, the size of the grains is also caused by the presence of chemical composition content which is generally in the form of quartz minerals, siderite, anorthite, montmorillonite, kaolinite, illite. ...
... Here, using Illumina sequencing of the 16S rRNA genes and chemical analyses, we investigated the concomitant effects of different pollutants (i.e., phosphorus and heavy metals) on bacterial and archaeal communities in river water and sediment samples. To this end, we used a section of the Olifants River network (South Africa) affected by the activities of the Phalaborwa industrial complex (PIC), which includes two mines and a fertilizer industry (Gomez-Arias et al. 2016;Heath et al. 2010;Marr et al. 2017). The mines extract metals and phosphate from alkaline rocks, whereas the fertilizer industry produces phosphoric acid attacking the phosphate with sulphuric acid. ...