Academic literature on the topic 'Gold mines and mining Environmental aspects Victoria'

Editor’s note: The aim of the Geology and Mining series is to introduce early career professionals and students to various aspects of mineral exploration, development, and mining in order to share the experiences and insight of each author on the myriad of topics involved with the mineral industry and the ways in which geoscientists contribute to each. Abstract Artisanal and small-scale mining (ASM) takes place in approximately 80 countries, and it is widespread in parts of Central and South America, Africa, Asia, and Oceania. Estimates range from 40 to 100 million ASM miners operating worldwide, and ASM generates a significant share of global production for commodities such as gold, tantalum, tin, gemstones, and diamonds. Geologists may encounter ASM activity when exploring new areas or when ASM miners move into existing exploration projects or the vicinity of large-scale mines. These interactions can be contentious, leading to conflicts that force project delays or abandonment. Alternatively, both groups can collaborate to generate mutual benefits, enabling mining companies to gain social license to operate and at the same time manage the environmental impacts of ASM, while the ASM miners maintain culturally and economically important livelihoods. Technical and social factors can help to predict the potential for coexistence or conflict with ASM operators, including the geology of the deposit type, the mining method, and the economic, legal, historical, and cultural context of a project. We present a series of case studies on ASM in Latin America, highlighting five coexistence models that have been previously implemented between mining companies and ASM operators. Our intent is to raise awareness of ASM, so that geologists can consciously consider its impacts on early exploration and subsequent decision-making. Secondly, we aim to encourage broader discussion of the role of ASM in mineral production and sustainable development.

Health and ecological risks associated with the use of mercury in gold mining are well known, with much recent attention focussed on contemporary small-scale artisanal mining. Legacy tailings from historical gold mining may also present ongoing risks, as the industry used large quantities of mercury with minimal environmental regulation to limit its discharge. This occurred in both alluvial (placer) mining and in processing auriferous ores. Analysis of historical data on mercury use in the mining industry in Victoria, Australia, indicates that at least 131 tonnes of elemental mercury were discharged into the environment as mine tailings between 1868–1888, with the total amount lost over the historic mining period likely to be much higher. The processing of pyritic ores also concentrated mercury losses in a small number of mining centres, including Bendigo, Ballarat, Castlemaine, Clunes, Maldon and Walhalla. This analysis provides a basis for further research needed to support improved management of legacy mine tailings.

Abstract Background Health issues are associated with artisanal mining in the DR Congo. The scenario is worst when artisanal mining is done informally or with limited material and technical resources. This paper argues that the adoption of healthy practices by artisanal miners might be limited given that it involves unrealistic socio-economic, and administrative aspects and access to health risk prevention means. Making a conceptual framework on the feasibility of revolutionizing artisanal mining practices linked to health risks in the DR Congo requires trans-disciplinary interventions and researches. This case study aims at co-analyzing with actors in the Luhihi artisanal gold mine, the epidemiology of health issues. It also aims at describing the dynamics of resources that mining actors mobilize or think they can mobilize in order to prevent health risks. Methods A “socio-anthropological” qualitative study with “transdisciplinary methods” was carried out the Luhihi artisanal mining. Data collection tools and methods included an exploratory survey, semi-structured interviews. Focus groups (FG) mixed with proportional piling were used to support the open-ended interview discussions. The actors interviewed were selected by “convenience sampling” and the saturation principle indicated the size of the sampling. In total, 67 persons were interviewed and 5 FG each consisting of 5 to 10 mining actors were organized. Data were triangulated among respondents to ensure their veracity and an “inductive thematic data analysis” was applied. Results Key findings are the role of actors involved the organization system at the Luhihi artisanal mining site; a description of a participative epidemiology and determinants of health issues; presentation of the importance of health risks as perceived by mining actors; the constraints in the common illenesses treatment; and opportunities of collective actions for gathering resources required for the organization of healthcare services. Conclusion The results are translated into a grid of powers and interests in relation to the mobilization of resources for the prevention and treatment of health issues. The dialogue for change regarding the ignorance of the actors to exposure to chemical risks such as to exposure mercury, silica, carbon monoxide, and cyanide also entailed the translation of the results. In addition, an analysis of the ability of artisanal mining actors to implement health risk prevention services was made.

Rocks of the South Island of New Zealand are locally enriched in metalloids, namely arsenic (As), antimony (Sb) and boron (B). Elevated levels of As and Sb can be found in sulphide minerals mostly in association with mesothermal gold deposits, whereas B enrichment occurs in marine influenced coal deposits. The mobility of these metalloids is important because they can be toxic at relatively low levels (e.g. for humans >0.01 mg/L of As). Their mobilisation occurs naturally from background weathering of the bedrock. However, mining and processing of coal and gold deposits, New Zealand's most economically important commodities, can significantly increase metalloid mobility. In particular, historic mines and associated industrial sites are known to generate elevated metalloid levels because of the lack of site remediation upon closure. This work defines and quantifies geological, mining, post-mining and regional processes with respect to metalloid, especially As, mobility. At the studied historic gold mines, the Blackwater and Bullendale mines, Sb levels in mineralised rocks were generally negligible (<14 ppm) compared to As (up to 10,000 ppm). Thus, Sb concentrations in solids and in water were too low to yield any meaningful information on Sb mobility. In contrast, dissolved As concentrations downstream from mine sites were found to be very high (up to 59 mg/L) (background = 10⁻� mg/L). In addition, very high As concentrations were found in residues (up to 40 wt%) and site substrate (up to 30 wt%) at the Blackwater processing sites (background < 0.05 wt%). Here, roasting of the gold ore converted the orginal As mineral, arsenopyrite, into the mineral arsenolite (As[III] trioxide polymorph) and volatilised the sulphur. The resultant sulphur-defficient chemical system is driven by arsenolite dissolution and differs significantly from mine sites where arsenopyrite is the main As source. Arsenolite is significantly more soluble than arsenopyrite. In the surficial environment, arsenolite dissolution is limited by kinetics only, which are slow enough to preserve exposed arsenolite over decades in a temperate, wet climate. This process results in surface waters with up to ca. 50 mg/L dissolved As. In reducing conditions, dissolved As concentrations are also controlled by the solubility of arsenolite producing As concentrations up to 330 mg/L. Field based cathodic stripping voltammetry showed that the As[III]/As[V] redox couple, in particular the oxidation of As[III], has a major control on system pH and Eh. Site acidification is mainly caused by the oxidation of As[III], resulting in a close link between As[V] concentrations and pH. Similarly, a strong correlation between calculated (Nernstian) and measured (electrode) Eh was found in the surface environment, suggesting that the overall Eh of the system is, indeed, defined by the As[III]/As[V] redox couple. Once the metalloid is mobilised from its original source, its mobility is controlled by at least one of the following attenuation processes: (a) precipitation of secondary metalloid minerals, (b) co-precipitation with - or adsorption to - iron oxyhydroxide (HFO), or (c) dilution with background waters. The precipitation of secondary minerals is most favoured in the case of As due to the relatively low solubility of iron arsenates, especially at low pH (~0.1 mg/L). Observations suggest that scorodite can be the precursor phase to more stable iron arsenates, such as kankite, zykaite, bukovskyite or pharmacosiderite and their stability is mainly controlled by pH, sulphur concentrations and moisture prevalence. Empirical evidence indicates that the sulphur-containing minerals zykaite and bukovskyite have a similar pH dependence to scorodite with solubilities slightly lower than scorodite and kankite. If dissolved As concentrations decline, iron arsenates potentially become unstable. Their dissolution maintains a pH between 2.5 and 3.5. This acidification process is pivotal with respect to As mobility, especially in the absence of other acidification processes, because iron arsenates are several orders of magnitude more soluble in circum-neutral pH regimes (~100 mg/L). From this, it becomes apparent that external pH modifications, for example as part of a remediation scheme, can significantly increase iron arsenate solubility and resultant As mobility. In contrast to As, the precipitation of secondary Sb and B minerals is limited by their high solubilities, which are several orders of magnitude higher than for iron arsenates. Thus, secondary Sb and B minerals are restricted to evaporative waters, from which they can easily re-mobilised during rain events. Metalloid adsorption to HFO is mainly controlled or limited by the extent of HFO formation, which in turn is governed by the availability of Fe and prevailing Eh-pH conditions. Thus, mineralisation styles and associated geochemical gradients, in particular pyrite abundance, can control the amount of HFO and consequent metalloid attenuation, and these can vary even within the same goldfleld. Furthermore, it was found that there is a mineralogical gradation between ferrihydrite with varying amounts of adsorbed As, amorphous iron arsenates and crystalline iron arsenates, suggesting that the maturity of mine waste is an important factor in As mineralogy. Once dissolved metalloids enter the hydrosphere, dilution is the main control on metalloid attenuation, which is especially pronounced at the inflow of tributaries. Dilution is, therefore, closely related to the size and frequency of these tributaries, which in turn are controlled by the regional topography and climate. Dilution is a considerably less effective attenuation mechanism and anomalous metalloid concentrations from mining related sites can persist for over 10 km downstream. The complex and often inter-dependent controls on metalloid mobility mean that management decisions should carefully consider the specific site geochemistry to minimize economic, health and environmental risks that can not be afforded. On a regional scale, background metalloid flux determines the downstream impact of an anomalous metalloid source upstream. For example, the Bullendale mine is located in a mountainous region, where rapidly eroding slopes expose fresh rock and limit the extent of soil cover and chemical weathering. Consequently, the background As flux is relatively low and As point sources, such as the Bullendale mine, present a significant contribution to the downstream As flux. In contrast, the bedrock at the Blackwater mine has undergone deep chemical weathering, resulting in an increased background mobilisation of As. Thus, the Prohibition mill site discharge, for example, contributes only about 10% to the downstream As flux. This information is relevant to site management decisions because the amount of natural background metalloid mobilisation determines whether site remediation will influence downstream metalloid chemistry on a regional scale.

Thesis (MPhil)--Stellenbosch University, 2011.
ENGLISH ABSTRACT: Gold mining in South Africa is an industry that is more than a century old. The impact of gold mines on communities and the environment are enormous. This thesis is a case study based in one of the major gold producers in South Africa that has been in operation for more than 50 years and has more than 30 years of life still left. Exploring the impact mining has had on communities and the environment, this thesis is a call for leadership action towards sustainable futures. This call is made through a suggested sustainable development leadership framework. Georgius Agricola gave a warning regarding the devastating environmental impacts of mining as early as 1556, however mining still has the same negative impacts to the environment and people. The argument in this thesis is that, it is only through genuine leadership that the impacts of mining can be mitigated. However leadership is looked at not from the position of the leader or the leadership style but from the belief system of the leader when it comes to environmental management and community development. The motivation for the study was based in observing how leadership at our Gold mine rallied behind prevention of mine closure when the mine was faced with electricity crisis in 2008. The electricity crisis demonstrated that it is through genuine and committed leadership that all challenges can be overcome including sustainable development crisis. The call for leadership at our mine is to demonstrate the same leadership commitment in addressing environmental and community development challenges. The literature review begins by highlighting sustainable development global challenges and initiatives to address them. This is followed by impacts of gold mining on society and the environment around the various regions of the world. Leadership belief systems are then discussed, highlighting, how belief systems influence the way a leader responds to environmental issues. In developing the sustainable development leadership framework findings from observations, conversations, interviews and focus group discussion that were conducted throughout the mine are presented. The aim of the research was to determine the understanding of employees on the impact of our company on communities, environment and themselves and also the employees’ opinions of leadership. The findings were that the majority of employees believe that leadership is not genuine in addressing community, employee safety and health, and environmental issues at our company and through interviews with leadership, the findings are that, environment and community issues are done for compliance and reputation purposes with no genuine belief that they should be done. To address this understanding a call to leadership is made through a suggested sustainable development leadership framework that takes into consideration the findings from the case study. The thesis ends by proposing that this suggested framework should be tested further within our company.
AFRIKAANSE OPSOMMING: Goud mynbou in Suid-Afrika is 'n bedryf wat meer as 'n eeu oud is. Die impak van goudmyne op gemeenskappe en die omgewing is enorm. Hierdie proefskrif is 'n gevallestudie wat gebaseer is op een van die groot goudprodusente in Suid-Afrika wat al vir meer as 50 jaar reeds in werking is en wat 'n veredere lewensverwagting van meer as 30 jaar het. Hierdie tesis is 'n ondersoek na die impak wat mynbou op die omliggende gemeenskappe en omgewing het asook 'n beroep om leieskap optrede vir volhoubare ontwikkeling. Hierdie beroep vir volhoubare ontwikkeling word gemaak deur middel van 'n volhoubare ontwikkeling leierskap raamwerk. Georgius Agricola het alreeds in 1556 gewaarsku teen die impak wat mynbou op die omgewing en mense sou hê. Vandag het mynbou het egter nog steeds dieselfde negatiewe impak op die omgewing en die mense. Die argument in hierdie tesis is dat dit slegs deur ware leierskap is dat die impak van mynbou versag kan word. Leierskap word egter nie bekyk uit die posisie van die leier of die leierskap-styl nie, maar eerder uit die gewetens oortuiging oogpunt van die leier wanneer dit kom by omgewingsbestuur en ontwikkeling van die gemeenskap. Die motivering vir hierdie studie is gebaseer op die waarneming van hoe leierskap by ons goudmyn mynsluiting voorkom het gedurende die 2008 elektrisiteitskrisis. Die elektrisiteitskrisis het getoon dat uitdagings sowel as volhoubare ontwikkelings krisisse wel deur ware en toegewyde leierskap oorkom kan word. Die versoek is nou vir ons myn om dieselfde leierskap toewyding toe te pas waar omgewing en gemeenskap ontwikkelings uitdagings aangepak word. Die literatuur oorsig begin deur die globale uitdagings op volhoubare ontwikkeling onder die vergrootglas te plaas en wys hoe om die uitdagings te addresseer. Dan volg die impak wat die goudmynbedryf het op die omgewing en samelewing van verskeie streke in die wêreld. Leierskap geloof oortuiging word dan bespreek met die klem op hoe geloofsoortuiging 'n invloed het op die manier wat 'n leier reageer op omgewings kwessies. Die ontwikkeling van die volhoubare ontwikkelings raamwerk is gebasser op obserwasies, gesprekke, onderhoude en fokusgroepsbesprekings van regoor die myn. Die doel van die navorsing was om die begrip van die werknemers te bepaal aangaande die impak wat ons maatskappy het op die gemeenskap, omgewing en hulself en ook om die werknemers se opinies van leierskap te bepaal. Die bevindinge was dat die meerderheid van die werknemers van mening is dat leierskap by ons maatskappy nie opreg is wanneer dit kom by aanspreek van gemeenskap kwessies, werknemer veiligheid en gesondheid, en omgewingskwessies nie. Deur middel van onderhoude met die leiers van ons maatskappy is ook bevind dat die omgewing en die gemeenskaps kwessies slegs aandag geniet aangesien dit vir die nakoming van vereistes en reputasiedoeleindes verys word en nie as gevolg van 'n werklike oortuiging dat dit gedoen moet word nie. Om hierdie begrip aan te spreek word 'n beroep gemaak tot leierskap deur middel van hierdie voorgestelde volhoubare ontwikkeling leierskap raamwerk wat die bevindings van die gevallestudie in ag neem. Die tesis eindig deur voor te stel dat hierdie voorgestelde raamwerk verder getoets moet word in ons maatskappy.

The subject of this thesis is the development of alternative approaches to environmental management and mine closure plans using case examples of the Big Bell/Cue Mining District and as a working example, an area of unconfined washout of historical gold-mine process tailings located in this arid inland region of Western Australia. This is considered appropriate in the light of the social and political thrust for industry to develop simultaneously positive economic, social and environmental outcomes from their activities. The Big Bell mining operation ceased mining in June 2003 and the Mine Closure Plan reflected a classical approach of minimization of public liability and strict compliance with legislative requirements. During the life of the modern mine the approach to rehabilitation was similarly classical in its approach It is intended for this document to inform the mining industry using the case example of the now closed Big Bell Mine as to how greater long-term outcomes may have been achieved for the State and the region for the future. This thesis specifically investigates alternative ways to approach rehabilitation in arid areas of Western Australia using the washout area as an example and trial area. This thesis has approached the issue by addressing the quantification of what has occurred through the gathering of baseline data of the case study area and then by the implementation of a series of relevant trials to identify appropriate eco-functional process-sensitive methods for rehabilitation as an alternative to current industry practice. Trials investigating the use of "retention banks" and "clay/seed balls" and the use of ex-mine milling waste carbon were conducted to investigate relevant possible techniques suitable for arid mine-site waste dump rehabilitation. Data analysis indicated that the main reason for the high level of degradation within the case study area is due to the smothering effect of the fine clayey tails cover and due to acidity of the tailings. A detailed examination of 92 soil samples found water infiltration of tails-washed areas as half that of control areas. Acidity of alluvium has declined from pH 5.2 to 3.8. The acidity has penetrated at depth to hardpan. Trials were commenced to rehabilitate the area using a combination of earthworks (retention banks and· scarification), pH- adjustment (using ex-mill carbon and crushed lime), and the use of native seed pelletised into clay-balls. The introduction of ex-mill carbon was shown to be effective in ameliorating pH in the tails wash area and improving its capacity to regenerate. Considering it is a widely available waste product with the gold mining industry it should be seriously considered in its application for rehabilitation purposes, and specifically in areas affected by severe acidification and desertification particularly by mismanaged tailings with pyrite content. The use of clay balls should also be subjected to further investigation. It is at least equal to the traditional use of raw seed and fertilizer with immediate and abundant rainfall. As this almost never occurs, it should prove to be superior, in delivering higher rates of viability for seed used. The thesis then attempts to integrate this study within the context of the wider issues of environmental management, specifically the best practice of mine closure plans and the adoption of sustainable economic, social and environmental outcomes from mining as an integral part of responsible operational environmental management plans. The thesis argues that the environmental management planning and specifically the Mine Closure Plan should not waste the myriad of opportunities that are the by-product of mining for the long-term sustainable benefit of the wider region. It is argued that if mining companies are serious about sustainability, then they cannot continue with short-term cycles of mining and closure. However to be realistic it will take concerted willingness from all stakeholders to pursue these outcomes. While a given mining operation can offer extensive resources and assets to support this approach the commercial and legislative pressures of core mining activities necessarily mean that mines are in fact encouraged to simply return the environment back to as natural state after operations are complete. Invariably this means hundreds of millions of dollars of infrastructure are levelled and scrapped to avoid all future liability, whilst the potential for sustainable outcomes is essentially ignored. The same Government that enforces the Mining Act and has a State Sustainability Strategy imposes the conditions which create unimaginative classical mine closure plans. Government, industry and the residents of regions must work together to seriously develop sustainable outcomes to mining.

Thesis (MA)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: Remote sensing and vegetation indices were evaluated for its usefulness to monitor the success of the rehabilitation programme of the decommissioned tailings storage facility (TSF1) of the Navachab Gold Mine, Karibib, Namibia. The study aimed to objectively illustrate the rehabilitation progression from tailings (baseline) to soil (capping) and vegetation (planted as well as natural). Baseline data sets of 2004 and 2005 were compared with imagery of 2009, 2010 and 2011. All the images were subjected to panchromatic sharpening using the subtractive resolution merge (SRM) method before georegistration. As no recent accurate topographical maps were available of the study area, the May 2010 image was used as a reference image. All other images were georegistered to this image. A number of vegetation indices (VIs) were evaluated. The results showed that the normalised difference vegetation index (NDVI) and the transformed vegetation index (TVI) provided the most promising results. Although the difference vegetation index (DVI) and enhanced vegetation index (EVI) distinguished the vegetation, rock, and soil classes, it was not as successful as the other VIs in classifying the rain water pond. TVI and NDVI were further evaluated for their efficacy in detecting changes. This was done by generating a series of change images and by qualitatively comparing them to false colour images of the same period. Both the NDVI and TVI delivered good results, but it was found that the TVI is more successful when water is present in the images. The research concludes that change analyses based on the TVI is an effective method for monitoring mine rehabilitation programmes.
AFRIKAANSE OPSOMMING: Afstandswaarneming en plantegroei-indekse is ge-evalueer vir die gebruikswaarde daarvan om sukses van die rehabilitasieprogram vir die geslote slykdam of tailings storage facility (TSF1) van die Navachab Goudmyn, Karibib, Namibië vas te stel. Die studie se doelwit was om die progressie in die rehabilitasie van slyk (basislyn) na grond (dekmateriaal) en plantegroei (aangeplant en natuurlik) te illustreer. Basislyndatastelle 2004 en 2005 is vergelyk met 2009, 2010, en 2011 beelde. Al die beelde is panchromaties verskerp deur die subtractive resolution merge (RSM) metode voor georegistrasie uit te voer. Aangesien geen onlangse, akkurate topografiese kaarte van die studiegebied beskikbaar was nie, is die beeld vir Mei 2010 as ‘n verwysingsbeeld gebruik. Al die ander beelde is op die laasgenoemde beeld gegeoregistreer. Die resultate het gewys dat die normalised difference vegetation index (NDVI) en die transformed vegetation index (TVI) die mees belowende resultate lewer. Al het die difference vegetation index (DVI) en enhanced vegetation index (EVI) goed onderskei tussen plantegroeiklasse en grond- en gesteentesklasse was dit nie so suksesvol met die klassifikasie van die reënwaterpoel nie. TVI en NDVI is verder geëvalueer vir effektiwiteit om verandering waar te neem. Dit is gedoen deur ‘n reeks van veranderingsbeelde te skep en dit dan kwalitatief met die valskleur-beelde vir dieselfde tydperk te vergelyk. Beide die NDVI en TVI het goeie resultate gelewer, maar die TVI was meer suksesvol om beelde met water te klassifiseer. Die navorsing lei tot die gevolgtrekking dat veranderingsanalises met die TVI ‘n effektiewe metode vir die monitoring van rehabilitasie programme is.

High concentrations of arsenic are found near gold-mine tailings. The most common form of arsenic found in soil is arsenate, which is a known toxicant. We used the standardised earthworm reproduction test for the species Eisenia andrei (E. andrei) to study the toxicity and bioavailability of arsenic-contaminated soil. Arsenic is toxic to earthworms as indicated by the decrease in survival and reproduction. Arsenic-spiked artificial soil was more toxic than arsenic-spiked field soil based on total arsenic concentration in soil. Moreover, soil from near mine tailings showed a reduced toxic effect despite its high soil arsenic concentration as compared to spiked field soil. Measurements of arsenic tissue concentrations in the earthworm indicated that uptake of arsenic into earthworm tissue was higher in spiked artificial soil as compared to spiked field soil and that the maximal body burden was 396 mug As/g dry tissue weight. However, when considering tissue arsenic concentration, spiked field soil is more toxic than spiked artificial soil. Therefore the tissue rather than soil content may better reflect the magnitude of arsenic toxicity to E. andrei.

A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in the partial fulfilment of the requirement for the Degree of Master of Science in Engineering
The impact of TMMM on Environmental Engineering is pervasive in all aspects. More critical aspects have been evaluated to quantify their impact on air and refrigeration of a typical deep, hot gold mine. ( abbreviation abstract)
Andrew Chakane 2018

Thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy. School of Animal, Plant and Environmental Science, University of the Witwatersrand, Johannesburg, South Africa. October 2016.
Mining has negative impacts on the environment in many different ways. One method developed to quantify some of these impacts is Landscape Function Analysis (LFA) and this has been accepted by some mining companies and regulators. In brief, LFA aims at quantifying the organization of vegetative and landscape components in a landscape into patches along a transect and quantifying, in a relative manner, three basic processes important to landscape functioning, namely: soil stability or susceptibility to erosion, infiltration or runoff, and nutrient cycling or organic matter decomposition. However, LFA is limited in large heterogeneous environments, such as those around mining operations, due to its localized nature, and the man hours required to collect a representative set of measurements for such large and complex environments. Remote sensing using satellite-acquired data can overcome these limitations by sampling the entire environment in a rapid and objective manner. What is required is a method of connecting these satellite-based measurements to LFA measurements and then being able to extrapolate these measurements across the entire mine surface. The aim of this research was to develop a method to use satellite-based hyperspectral imagery to predict landscape function analysis (LFA) using partial least squares regression (PLSR). This was broken down into three objectives: (1) Collection of the LFA data in the field and validation of the LFA indices against other environmental variables collected at the same time, (2) validation of PLSR models predicting LFA indices and various environmental variables from ground-based spectra, and (3) production of risk maps based on predicting LFA indices and above-ground biomass using PLSR models and Hyperion satellite-based hyperspectral imagery. Although the study was based in grasslands at two mining regions, West Wits and Vaal River, a suitable Hyperion image was only available for Vaal River. A minimum of 374 points were sampled for LFA indices, ground-based spectra, above-ground biomass and soil cores along 2880 m of LFA transect from both mine sites. Soil cores were weighed fresh before sieving with a 2 mm sieve to separate root and stone fractions. The sieved soil fraction was tested for pH, EC, SOM, and for the West Wits samples, organic nitrogen and total extractable inorganic nitrogen. There was one modification to the LFA method where grass patches were collapsed into homogenous units as it was deemed not feasible to sample 180 m transects at grass tuft scales of 10 – 30 cm, but other patch definitions followed the LFA manual (Tongway and Hindley, 2004). Evidence suggested that some of the different patch types, in particular the bare/biological soil crust – bare grass – sparse grass patch types, represented successional stages in a continuum although this was not conclusive. There also was evidence that the presence or absence of cattle play a role in some processes active in these grasslands and erosion is mainly through deflation, rain splash and sheet wash. Generally the environmental variables supported the LFA indices although the nutrient cycling index was representative of above-ground nutrient cycling but not below-ground nutrient cycling. Models derived with PLSR to predict the LFA indices from ground-based spectral measurements were strong at both mine sites (West Wits: LFA stability r2 = 0.63, P < 0.0001; LFA infiltration r2 = 0.75, P < 0.0001; LFA nutrient cycling r2 = 0.73, P < 0.0001; Vaal River: LFA stability r2 = 0.39, P < 0.0001, LFA infiltration r2 = 0.72, P < 0.0001, LFA nutrient cycling r2 = 0.54, P < 0.0001), as were PLSR models predicting above-ground biomass (West Wits above-ground biomass r2 = 0.55, P = 0.0003; Vaal River above-ground biomass r2 = 0.79, P < 0.0001) and soil moisture (West Wits soil moisture r2 = 0.45, P = 0.0017; Vaal River soil moisture r2 = 0.68, P < 0.0001). However, for soil organic matter (r2 = 0.50, P < 0.0001) and EC (r2 = 0.63, P < 0.0001), Vaal River had strong prediction models while West Wits had weak models for these variables (r2 = 0.31, P = 0.019 and r2 = 0.10 and P < 0.18, respectively). For EC, the wide range of soil values at Vaal River in association with gypsum crusts, and low values throughout West Wits explained these model results but for soil organic matter, no clear explanation for these site differences was identified. Patch-based models could accurately discriminate between spectrally well-defined patch types such S. plumosum patches but were less successful with patch types that were spectrally similar such as the bare/biological soil crust – bare grass – sparse grass patch continuum. Clustering similar patch types together before PLSR modelling did improve these patch-based spectral models. To test the method proposed to predict LFA indices from satellite-based hyperspectral imagery, a Hyperion image matching 6 transects at Vaal River was acquired by NASA’s EO-1 satellite and downloaded from the USGS Glovis website. LFA transects were partitioned to match and extract pixel spectra from the Hyperion data cube. Thirty-one spectra were separated into calibration (20) and validation (11) data. PLSR models were derived from the calibration data, tested with validation data to select the optimum model, and then applied to the entire Hyperion data cube to produce prediction maps for five LFA indices and above-ground biomass. The patch area index (PAI) produced particularly strong models (r2 = 0.79, P = 0.0003, n =11) with validation data, whereas the landscape organization index (LOI) produced weak models. It is argued that this difference between these two essentially similar indices is related to the fact that the PAI is a 2-dimensional index and the LOI is a 1-dimensional index. This difference in these two indices allowed the PAI to compensate for some burned pixels on the transects by “seeing” the density pattern of grass tufts and patches whereas the linear nature of the LOI was more susceptible to the changing dimensions of patch structure due to the effects of fire. Although validation models for the three LFA indices of soil stability, infiltration and nutrient cycling were strong (r2 = 0.72, P = 0.004; r2 = 0.66, P = 0.008; r2 = 0.70, P = 0.005, n = 9 respectively), prediction maps were confounded by the presence of fire on some transects. The poor quality of the Hyperion imagery also meant great care had to be taken in the selection of models to avoid poor quality prediction maps. The 31 bands from the VNIR (478 – 885 nm) portion of the Hyperion spectra were generally the best for PLSR modelling and prediction maps, presumably because of better signal-to-noise ratios due to higher energy in the shorter wavelengths. With two satellite-based hyperspectral sensors already operational, namely the US Hyperion and the Chinese HJ-1A HSI, and a number expected to be launched by various space agencies in the next few years, this research presents a method to use the strengths of LFA and hyperspectral imagery to model and predict LFA index values and thereby produce risk maps of large, heterogeneous landscapes such as mining environments. As this research documents a method of partitioning the landscape rather than the pixel spectra into pure endmembers, it makes a valuable contribution to the fields of landscape ecology and hyperspectral remote sensing.
LG2017

Msc.
This study focuses on the functional evaluation of a gold Tailings Storage Facility (TSF), the Fleurhof TSF (designated slimes dam 2L3), which is representative of gold slimes (tailings) dams in the Witwatersrand. The aim is to evaluate the rehabilitation status (in terms of species composition and landscape function) of TSF surfaces that were planted ~20 to ~40 years ago using the most common rehabilitation practice, namely pasture grassing. Pasture grassing aims to obtain rapid dust control. Mine closure was not considered at the time, and the vegetation was hence not designed with ecological processes or long-term objectives in mind. However, over time, grassing practices became routine in the TSF vegetation industry, and the contribution that they have made towards surface rehabilitation needs to be assessed against the current site closure objectives. On the selected site, evaluations of vegetation cover, species composition, and substrate physical and chemical properties were conducted in 1975 (Thatcher, 1979). The aim of the current mid-summer study in 2009 was addressed by assessing the same parameters of vegetation cover, species composition, and soil physical and chemical properties, and comparing these to the results of the previous assessment in 1975. Landscape Function Analysis (LFA – an index-based method of evaluating the retention of resources by surfaces and soil condition), was applied to determine the landscape function (stability, infiltration and nutrient cycling that are derived from the eleven soil surface assessment indicators), and compared with the landscape function of natural analogues in the same locality. Landscape organisation (also an indicator of LFA) was used to investigate the contribution of vegetation overall, and of discrete plant functional groups to landscape functionality. A total of 35 plant species were observed in the quadrats (56 species on the TSF overall), with 51% of species overall being alien. Perennial vegetation and cryptogam covers contributed the most to stabilising the TSF slopes and flat (top) surfaces. The percentage of vegetation basal cover on the TSF (30% – 70%) was lower than for analogue grassland sites on a nearby hill (80% – 100%). Lower basal vegetation cover on the TSF than on the analogue site, were associated with lower LFA indices of stability on all TSF slope aspects (P = 8.19 x 10-13 for all aspects), iii lower nutrient cycling for the northern and southern TSF slopes (south aspect P = 4.20 x 10-6; top aspect P = 0.03), and lower infiltration on the southern slope of the TSF (P = 2.68 x 10-6). However, a higher infiltration on the northern TSF aspect (P = 0.02) than on the analogue site, was attained. Perennial tussock grass patch types (which included perennial forbs) made the largest contribution to the soil surface assessment (SSA) indicators on the TSF and analogue sites, and therefore to the LFA indices that were derived from these SSA indicators. The contribution of woody patches to function was not evaluated.

The upper part of the Revue basin in the Manica District, Mozambique is located in a mountainous area underlain by rocks of the Manica greenstone belt. This greenstone belt has alluvial gold deposits in the Revue river and its tributaries Chua and Zambuzi. Alluvial gold in the Manica District has been mined by local people using artisanal mining methods (panning) and by small scale companies. The recovery process of gold involves washing of the auriferous gravel with large quantities of water and the surface water quality has been impaired in this process. The aim of this dissertation is to assess the impact of alluvial gold mining on surface water quality in the Revue basin. Physical and chemical characteristics of the surface water were determined upstream of, within and downstream of the mining area and in the main tributaries immediately before flowing into the Revue river. Upstream of the mining area the water is clear and the rock types of the Manica greenstone belt are likely to be the only source of metals dissolved in the water. Metal concentrations are generally low except Cd, Mo and Ni but the water in this area meets all World Health Organization (WHO) recommendations for drinking water. In contrast within the mining area there are signs of pollution. The water is cloudy and the highest concentrations of most metals are found in the lower part of this area where mining activity is very intense. Thus, the alluvial gold mining is responsible for elevated metal concentrations and constitutes the major point source of pollution in the Revue basin. Water quality within the mining area has been affected and metals Ba, Pb and Mn have concentrations exceeding the WHO recommended values for drinking water. Downstream of the mining area the impounded water in the Chicamba Dam, which is the source of potable water for Chimoio City, reduces the water flow in the Revue river and sedimentation of suspended sediments occurs, together with associated adsorption and precipitation processes. This result in general improvement of water quality with only Ba and Pb concentrations remaining above the WHO recommended values for drinking water. Increase in concentration of metals AI, Ba, K, Pb and Sr occurring in the Chicamba Dam is likely to be due to input to the dam of water from rivers which cross the Granite-gneiss Complex. Geochemical speciation modelling using MINTEQA2 program suggests that the behaviour of metals Cr, AI, Mn and Fe is controlled by redox and precipitation reactions while the behaviour of As, Cd, Zn, Cu, Ni, Pb, Ba and Ca is controlled by adsorption on the sediment surfaces. Changes in environmental conditions, such as pH and dissolved organic matter (DOM) could result in metals being released back into the water. Modelling the effect of a change in pH and variation in DOM indicate that adsorption and precipitation would decrease with decreasing pH values and with increasing DOM. The chemical form of dissolved metals, the type of interactive processes (absorption and precipitation) and concentration of particulate matter gives the distribution of pollutants while the transport process affect the fate of pollutants in the Revue river water.
Thesis (M.Sc.)-University of Natal, Durban, 2000.

A research report submitted in partial fulfilment of the requirements for the Master of Science in Town and Regional Planning at the school of architecture and planning to the University of the Witwatersrand, Johannesburg, 2016
Mining and the mining experience is one that has been written about extensively in academia. The history of mining in South Africa has not only shaped the physical landscape of the country but has shaped peoples understanding of the different spaces. The changing dynamics of mining, especially gold mining has played a role on the different experiences in contemporary South Africa. The decline in employment and production in the sector has meant that people in these gold mining towns have had to adapt to the changing times. The concept of resilience allows the research to view spaces such as that of Khutsong to see how people in such places are able to be resilient and the factors impacting on their resilience.
MT2017