Дисертації з теми "Coal mine waste"

Many countries around the world use coal as fuel for the purpose of power generation. The extraction of coal produces large volumes of waste rock (WR) that are sometimes sulphide rich (principally containing iron sulphides such as pyrite (FeS2) and pyrrhotite (Fe1-xS)), with varying quantities of trace elements such as As, Si, Cu, Zn, Ni, Co, Mo and Cr etc). Such waste is environmentally sensitive due to the risk of oxidation in presence of atmospheric oxygen and water. Sulphide oxidation may result in acidic waters (acid mine drainage, AMD), which often contains high loads of dissolved metals. Coal combustion results in large amounts of fly ash (FA), which also is of environmental concern. However, FA is alkaline and may potentially be used for neutralisation of AMD. Therefore, the AMD producing potential of WR from coal mining and the neutralisation potential of FAs from coal and biomass combustion was studied with the ultimate goal to develop a methodology to decrease the environmental problems related to these materials.WR was sampled form the Lakhra coal field in Pakistan, which has an estimated coal reserve of 1.3 Bton, from lignite to sub-bituminous in quality. The WR samples were characterised by mineralogical and geochemical methods and the acid producing potential was determined by static (Acid Base Accounting) and kinetic (modified humidity cells test) methods. Besides organic material, the WRs are composed of quartz, pyrite, kaolinite, hematite and gypsum with varying amounts of calcite, lime, malladerite, spangolite, franklinite and birnessite. The Lakhra WR has strong potential to generate AMD (-70 to -492 kg CaCO3/ton) and pollute natural waters by leaching of elements such as Cd, Co, Cr, Cu, Ni, Pb, Zn, Fe and SO42-. Three different FAs based on the origin, fuel type and storage methods were studied. They were characterised by mineralogical and geochemical methods, the leachability was studied by batch leaching tests and the potential for buffering acids and neutralisation of AMD was quantified. Fly ash from burning i) brown coal (lignite) in Pakistan (PK), ii) black (bituminous) coal from Finland (FI) and iii) biomass FA provided by a sulphate pulp and paper mill in Sweden (SE) were studied. All ashes contained quarts, PK also iron oxide, anhydrite, and magnesioferrite, FI also mullite and lime, and SE also calcite and anorthite. All ashes were enriched in As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn compared to continental crust, and all ashes had a strong neutralisation potential, the bioash, SE, in particular. The results are encouraging and suggest that it is possible to use FA to mitigate the environmental problems with coal mine WR. Methods for that will be the focus for the continued research.
Godkänd; 2014; 20141013 (asiqur); Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Asif Qureshi Ämne: Tillämpad geologi/Applied Geology Uppsats: Potential of Fly Ashes for Neutralisation of Acid Mine Drainage from Coal Mine Waste Rock Examinator: Professor Björn Öhlander Institutionen för samhällsbyggnad och naturresurser Luleå tekniska universitet Diskutant: Dr Josef Mácsik Ecoloop AB Stockholm Tid: Torsdag den 18 december 2014 kl 13.00 Plats: E246, Luleå tekniska universitet

Low-grade coal, a poor source of energy, has long been regarded as waste material by the coal mining industry. Biological degradation of this coal material by ligninolytic fungal strains presents a viable strategy towards eliminating this unusable fossil fuel. To this end, a novel and patented bioprocess termed Fungcoal was developed. Fungcoal is a biological process utilised in the in situ treatment of waste coal and is based on the mutualistic relationship between the fungus Neosartorya fischeri and the graminaceous species Cynodon dactylon. The process facilitates the rapid conversion of waste coal into soil-like material that stimulates establishment of vegetation for eventual coal dump rehabilitation. While a number of in vitro studies have identified various fungal strains as efficient coal degraders, the mechanisms involved in the Fungcoal-stimulated degradation process have not been fully elucidated. Furthermore, implementation of Fungcoal at both pilot and commercial scale has not been achieved. Thus the objective of this work was to investigate Fungcoal as a bioprocess via examining the role of coal degrading fungi (CDF) and grasses as biocatalysts in coal biodegradation and for the self-cladding of waste coal dumps. Initially, waste coal degradation by N. fischeri, strain ECCN 84, was investigated, specifically focusing on the mechanisms underpinning the process. In vitro studies showed the addition of waste coal induced active fungal colonisation resulting in increased fungal biomass. Increased extracellular laccase (LAC) activity, occuring concomitantly with an increase in hyphal peroxisome proliferation, was also observed in the coal supplied fungal cultures. Analysis of the colonised waste coal revealed a time dependent reduction in the percentage weight of elemental carbon coupled with an increase in elemental oxygen. The results supported metabolism and degradation of waste coal by N. fischeri strain ECCN 84 and involvement of fungal extracellular laccase. The contribution of C. dactylon, a C4 grass species to in situ biodegradation of waste coal in the presence of coal degrading and mycorrhizal fungi (MF) was also investigated. Enhanced degradation of the waste coal into a humic soil-like material was observed within the rhizosphere. Analysis of the resultant substrate revealed an increased concentration of highly oxidised humic-like substances (HS). Fungi remained viable in the rhizosphere up to 47 weeks post-inoculation and cultivation of C. dactylon, indicating the resultant humic substance-rich rhizosphere provided an environment conducive for microbial proliferation and activity. Furthermore, humic substance enrichment of waste coal substrates supported germination and seedling emergence of several agronomic species including Zea mays (corn), Phaseolus vulgaris (bean), Pisum sativum (pea), and Spinacia oleracea (spinach). Use of various cladding materials to support coal biodegradation, by fungus-grass mutualism and rehabilitation of waste dumps was evaluated at commercial scale. While substantial physico-chemical changes were not evident in the absence of cladding or where waste coal was used as cladding material, successful establishment of grass cover and diversity was achieved within three hydrological cycles on dumps cladded with weathered coal. Work presented in this thesis successfully demonstrates the degradation of waste coal by N. fischeri. The biodegradation process included enhanced extracellular LAC activity coupled with increased 3 waste coal oxidation. Increased HS concentration of waste coal substrate supported germination and early seedling establishment of several agronomic species. At commercial scale a co-substrate in the form of carbon-rich weathered coal was essential to support fungus-grass mutualism and Fungcoal-induced rehabilitation. These findings support the developed Fungcoal concept and the underpinning rationale that the phyto-biodegradation of waste coal indeed depends on the mutualistic interactions between grass root exudates and the ligninolytic and mycorrhizal fungi. Taken together, these findings provide practical evidence of the contribution of fungi and grasses as mutualists in the biodegradation of waste coal and sustainable rehabilitation of waste coal dumps

This thesis presents details of investigations into the potential for co-disposal of the two rejects from Clarence Colliery and Kable's Transport Sand Mine. Column experiments were undertaken to simulate field conditions. The experiment consisted of: 1/. creating the required co-disposal arrangement and structure in containers 2/. infiltrating water through each container and measuring the rates of infiltration and overflow 3/. measuring the chemical properties of the leachate water. Geotechnical tests of co-disposal pile stability were undertaken using a specially constructed shear box. Results of this study suggest the co-disposal of course coal washery reject from Clarence Colliery with clay tailings from Kable's Transport Sand Mine is a feasible option for managing the generation of acetic drainage. It is recommended that field trials comprise layers of coal reject and clay tailings in a 9:1 ratio. Layering the coal reject with clay tailings creates a semi-permeable barrier which acts to restrict water percolation through the reject as well as reacting with the leachate to increase the leachate pH and adsorb metals
Master of Engineering (Hons)

Alkaline fly ash has been studied as a liming agent within coal refuse fills to reclaim acid-forming refuse. Previous studies focused on bulk blending ash with acid-forming (pyritic) refuse. A better representation of field conditions is a â pancake layerâ of ash above the refuse. A column study was initiated to evaluate the leachate chemistry from acid-forming refuse-ash bulk blends vs. ash over refuse layers. An acidic and an alkaline ash were blended with, or layered over, acid-forming refuse and sandstone and packed into columns which were leached with deionized water twice a week for 24 weeks under unsaturated conditions. Leachates were analyzed for pH, electrical conductivity, and a suite of elements with a focus on the oxyanions of As, Cr, Mo, and Se. A sequential extraction procedure revealed a significant portion of the elements in the residual fraction for the refuse/spoil substrates and in metal-oxide bound fractions for the ashes prior to leaching, and a general trend for a greater proportion of oxyanion elements to be associated with metal oxide fractions after leaching. Bulk-blended treatments maintained higher leachate pH than corresponding layered treatments. The acidic ash and refuse pancaked treatments exhibited relatively high initial concentrations of most elements analyzed. Pancake layers of ash over refuse are an inadequate co-disposal method to prevent and mitigate acid mine drainage. Blending alkaline ash with refuse to acid-base accounting specifications should improve leachate quality overall, but there may be water quality concerns for loss of Se and other soluble ions during initial leaching events.
Master of Science

This thesis presents details of investigations into the potential for co-disposal of the two rejects from Clarence Colliery and Kable's Transport Sand Mine. Column experiments were undertaken to simulate field conditions. The experiment consisted of: 1/. creating the required co-disposal arrangement and structure in containers 2/. infiltrating water through each container and measuring the rates of infiltration and overflow 3/. measuring the chemical properties of the leachate water. Geotechnical tests of co-disposal pile stability were undertaken using a specially constructed shear box. Results of this study suggest the co-disposal of course coal washery reject from Clarence Colliery with clay tailings from Kable's Transport Sand Mine is a feasible option for managing the generation of acetic drainage. It is recommended that field trials comprise layers of coal reject and clay tailings in a 9:1 ratio. Layering the coal reject with clay tailings creates a semi-permeable barrier which acts to restrict water percolation through the reject as well as reacting with the leachate to increase the leachate pH and adsorb metals

Waste rock piles from coal mining of tertiary bituminous coal in Longyearbyen, Svalbard, show sulfide oxidation and subsequent acid mine drainage (AMD) production. The aim was to establish deeper understanding of AMD prediction based on Mineralogy and Geochemistry of coal and AMD samples. Mineralogical investigation of both coal and rock samples was performed with Automated SEM (ZEISS-Sigma VP300-Mineralogic System) as well as RAMAN. ICP-MS analysis was performed on solid and water samples. The pH from in situ measurements of AMD between 2,5-7,0. Eh varied from 222-569 mV (corresponding pe value of 3,7-9,6). This study showed that time of AMD in an oxidative environment was a key factor in iron concentration and iron speciation the AMD. This could not however be concluded in terms of age of mine site but rather the site-specific setting. The main minerals found in coal samples were pyrite (FeS2), siderite (FeCO3), calcite (CaCO3) and apatite (Ca5(PO4)3). Pyrites were identified with framboidal and euhedral textures and were found inside the maceral matter and in over- and underlying rocks respectively. SEM analysis of coal samples indicated that the modes of mineral formation was changing over the course of the Longyear seam. This study found that framboidal or euhedral textures of pyrite had different impacts in the AMD production. Framboidal pyrite was found to generate a greater amount of acidity than euhedral pyrites due to larger specific surface area and could therefore pose larger problems in AMD management.

Thesis (MSc)--Stellenbosch University, 1997.
ENGLISH ABSTRACT: The activity of iron-oxidizing bacteria, for example, Thiobacillut. ferrooxidans, in the outer layers of coal waste dumps results in the oxidation of pyrite with the formation of large volumes of acid mine drainage. The process requires atmospheric oxygen and moisture. Acid mine drainage may possibly be controlled by creating unfavourable environmental conditions in dumps for the iron-oxidizing bacteria. The present research investigated the possibility of inhibiting these bacteria and consequently acid formation in coal waste dumps by means of different dump construction techniques. Physical and chemical conditions, acid formation and populations of four groups of bacteria which might produce acid were studied in the outer layers of ten differently constructed pilot scale coal waste dumps at the Kilbarchan Mine near Newcastle, Kwazulu-Natal, from September 1993 to July 1995. Dump covers consisting of a 30-cm or 70-cm layer of Estcourt soil of low permeability covered with 70 cm or 30 cm, respectively, of more permeable Avalon soil produced anaerobic conditions in the dumps throughout most of the 22 months of the test period, as did a cover of 70 cm compacted plus 30 cm uncompacted Avalon soil alone. An uncoMpacted 30-cm or compacted 50- cm Avalon soil cover proved ineffective in causing prolonged anaerobic conditions. Uncovered dumps showed only slight reduction of oxygen in the coal waste after heavy rains. Pockets of acidity were detected on several occasions in the coal waste below the 50-cm Avalon soil layer from the time of construction and progressively increasing acidity in the uncovered dumps and the waste below the 30-cm Avalon soil cover. Iron-oxidizing bacterial populations of the T. ferrooxidans type have tended to be higher in the uncovered dumps and Avalon soil-covered dumps showing acidification than in the non-acidified dumps covered with 1 m of Avalon soil or Avalon and Estcourt soil. Associated populations of iron-oxidizing bacteria of the Metallogenium type, acidophilic and non-acidophilic thiosulphate-oxidizing bacteria were generally low in the coal waste of the dumps. Thus, five of the soil covers, all with a thickness of 1 m, but not covers with a thickness of 0.5 m or less, proved effective for almost 2 years in inhibiting the diffusion of oxygen to the underlying coal waste in the pilot scale dumps and also appeared to suppress the populations of iron-oxidizing bacteria believed to be implicated in acid formation in the coal waste. These results suggest that coal waste dumps in South Africa should be covered with soil layers of 0.5-1.0 m thick to prevent the generation of acid mine drainage.
AFRIKAANSE OPSOMMING: Die aktiwiteit van ysteroksiderende bakteriee soos Thiobacillus ferrooxidans, in die buitenste lae van steenkoolafvalhope, veroorsaak die oksidasie van piriet met die gevolg dat groot volumes suur mynafloopwater gevorm word. Hierdie proses benodig suurstof en vog. Suur mynafloopwater kan moontlik beheer word deur 'n situasie te skep waar die toestande in die hope ongunstig is vir die ysteroksiderende bakteriee. Die huidige navorsing het die moontlikheid ondersoek om hierdie bakteriee te inhibeer deur verskillende afvalhoopontwerpe op die proef te stel en sodoende suurvorming in steenkoolmynhope te beperk. Die fisiese en chemies kondisies, suurvorming en populasies van vier verskillende bakterie-groepe wat dalk by suurvorming betrokke is, is vanaf September 1993 tot Julie 1995 bestudeer in die buitenste lae van tien verskillend gekonstrueerde loodsskaalafvalhope by die Kilbarchan myn naby Newcastle in KwaZulu-Natal. Afvalhoopbedekkings bestaande uit 'n 30-cm of 70-cm Estcourt grond met 'n lae permeabiliteit bedek met'n 70-cm of 30-cm laag van meer deurlaatbare Avalon grond het anaerobe kondisies veroorsaak. Ongekompakteerde 30-cm en gekompakteerde 50-cm Avalon grondlae het egter nie bestendige anaerobe kondisies in die hope veroorsaak nie. Die onbedekte hope het aerobics gebly met slegs effense dalings van suurstofkonsentrasies gedurende en na swaar reens. Geisoleerde monsters uit die steenkoolafval onder die 50-cm Avalon grondlaag het vanaf die begin van die toetsperiode tekens van suurvorming getoon. Die onbedekte steenkoolafval en die van die sel met 'n 30-cm Avalon grondlaag het met verloop van tyd al hoe meer suur geword. Die ysteroksiderende bakterie-populasies van die T. ferrooxidans tipe het geblyk om in die onbedekte en Avalon grondbedekte hope wat tekens van suurvorming getoon het hoer te wees as in die hope wat met 'n 1-m laag Avalon grond of Avalon en Estcourt grond bedek is en geen tekens van suurvorming getoon het nie. Ysteroksiderende bakteriepopulasies van die Metallogenium tipe, nieasidofiele en asidofiele tiosulfaatoksiderende populasies was oor die algemeen laag in die steenkoolafvalhope. Vyf van die grondlae wat alma! 1 m dik was het dus geblyk om effektief te wees in die bekamping van die infiltrasie van suurstof na die onderliggende steenkoolafval in die loodskaalhope. Dit lyk asof daardie lae die ysteroksiderende populasies betrokke by suurvorming onderdruk het. Die 0.5-m grondbedekking het egter nie so 'n sterk onderdrukkende effek op die suurstofinfiltrasie of die bakteriepopulasie gehad nie. Na aanleiding van hierdie resultate blyk dit dat steenkoolafvalhope in Suid-Afrika met minstens 0.5 tot 1..0 m grond bedek moet word om effektief die probleem van suur mynafloopwater te bekamp.

The separate land disposal of coal refuse and fly ash presents difficulties throughout the Appalachian region, both in terms of disposal costs per acre and in terms of its potential environmental impacts on soil, ground water, revegetation, and slope stability. The purpose of this study was to determine how fly ash addition to coal refuse would impact on certain geotechnical properties of the refuse disposal piles, and whether the refuse-fly ash blends would be suitable as co-disposed materials. Accordingly, the compaction, permeability and shear strength characteristics of the refuse-fly ash blends were experimentally determined for varying fly ash percentages. The compaction test results indicated that, with increasing fly ash, the maximum dry density of these blends marginally decreased. The permeability test results showed that the permeability of the test specimens progressively decreased with the increase in fly ash. The shear strength results demonstrated that the addition of fly ash did not significantly influence the shear strength of the refuse. The critical factor of safety determined during slope stability analysis revealed that the tested slope geometries were stable for long term, drained conditions (using the STABGM computer program). The volume change analysis determined that there was a minimal expansion in the volume of refuse when it was blended with fly ash. However, it may be noted that all the stated results depend on a number offactors, including the nature of the refuse and fly ash used. Therefore, these findings would be specific to bulk blends of coal refuse and fly ash only. In general, this study indicates that fly ash can be beneficially reused with respect to the geotechnical properties evaluated. Co-disposal of fly ash and coal refuse may be a reasonable alternative to present disposal methods.
Master of Science

Thesis (MSc)--Stellenbosch University, 1998.
One copy microfiche.
ENGLISH ABSTRACT: The biologically catalysed oxidation of pyrite in the outer layers of coal waste dumps leads to the formation of acid mine drainage. The oxidation of pyrite to ferric iron and sulphate is a complex process involving various abiotic and biologically catalysed reactions. Pyrite is abiotically oxidized by ferric iron, with the formation of thiosulphate and ferrous iron. Thiosulphate decomposes to form various inorganic sulphur compounds. Bacterial catalysis of pyrite oxidation is achieved by iron-oxidizing bacteria oxidizing ferrous iron to ferric iron. Bacteria that oxidize sulphur compounds assist the catalysis by oxidizing thiosulphate and its decomposition products. Heterotrophic organisms may play a role by consuming organic substances inhibitory to the lithotrophic bacteria. Abiotic ecological factors, acid formation and populations of iron-oxidizing bacterial groups were studied in 10 differently constructed pilot scale coal waste dumps, as the second phase of a study which started in September 1993. Gas samples were withdrawn weekly from coal waste through permanently buried stainless steel probes, for analysis in the field using a portable oxygen/carbon dioxide meter. Samples of coal waste were extracted by auger for analysis of moisture, pH and microbial populations. The analyses of oxygen and pH can be recommended for the routine monitoring of rehabilitated waste dumps. Covers of Avalon soil 0.3 or 0.5 m thick, were not adequate to prevent acidification. Coal waste covered with 0.7 m compacted beneath 0.3 m uncompacted Avalon soil, showed a slow pH decline, but reached approximately pH 3 in 1997. Covers of compacted Estcourt soil beneath tmcompacted Avalon soil to a cover depth of 1 m were effective in preventing acidification and generally kept the coal waste anaerobic. However, all covers developed cracks during drought conditions in 1995, allowing aeration. Low pH of some samples from these dumps during 1995/1996 may have indicated the start of acidification. Bacteria oxidizing high concentrations of ferrous iron and considered to be Thiobacillus ferrooxidans, were monitored routinely, but may not have been the dominant iron-oxidizer, as population counts using media with a lower ferrous iron concentration were higher. The majority of the latter organisms could also not oxidize sulphur, hence were not T. ferrooxidans. The populations of the high ferrous iron-oxidizing bacteria were affected by pH, tending to be high in acidified and low in non-acidified coal waste. Investigations of microbial populations forming iron-oxidizing consortia in enrichment cultures from coal waste and acid drainage samples showed the presence of T. ferrooxidans, the heterotrophic bacterial genus Acidiphilium, fungi of the genus Penicillium, unidentified filamentous fungi, including Cladophialophora-like morphological types, and a yeast of the genus Dipodascus. In interaction studies, the Penicillium isolate had an inhibitory effect on T. ferrooxidans (subjected to organic compound stress), but the Cladophialophora-like fungi reduced inhibition by organics. Fungi have not previously been studied in detail as components of iron-oxidizing consortia, but the bacterial isolations agree with those elsewhere, indicating that appropriate conclusions from acid mine drainage research in other parts of the world can be applied in KwaZulu-Natal.
AFRIKAANSE OPSOMMING: Die biologies gekataliseerde oksidasie van piriet in die buitenste lae van steenkoolafvalhope lei tot die vorming van suur mynafloopwater. Die oksidasie van piriet tot ferri-yster en sulfaat is 'n komplekse proses wat abiotiese en biologies gekataliseerde reaksies insluit. Piriet word abioties deur ferri-yster geoksideer, met die vrystelling van tiosulfaat en ferro-yster. Tiosulfaat verval om verskeie anorganiese swawelverbindings te vorm. Bakteriese katalise van pirietoksidasie word deur ysteroksiderende bakteriee wat ferro-yster na ferri-yster oksideer, bewerkstellig. Bakteriee wat swawelverbindings oksideer maak 'n bydrae tot die katalise deur tiosulfaat en vervalprodukte daarvan te oksideer. Heterotrofe organismes mag ook 'n rol speel deur organiese verbindings wat die litotrofe bakteriee mag inhibeer, te verbruik. Abiotiese ekologiese faktore, suurvorming en bevolkings ysteroksiderende bakteriee is in 10 verskillend gekonstrueerde loodsskaal steenkoolafvalhope bestudeer, as die tweede fase van 'n studie wat in September 1993 begin het. Gas monsters is weekliks uit die steenkoolafval onttrek deur vlekvrye staal peilers wat permanent daarin begrawe is, en met behulp van 'n draagbare suurstoflkoolstofdioksiedanaliseerder in die veld ontleed. Monsters van die steenkoolafval is met behulp van 'n kleiboor vir die analise van vog, pH en mikrobepopulasies geneem. Die analise van suurstof en pH kan aanbeveel word vir die roetiene monitering van gerehabiliteerde afvalhope. Bedekkings van 0.3 of 0.5 m Avalongrond was nie voldoende om suurvorming te verhoed nie. Steenkoolafval wat met 0.7 m gekompakteerde en 0.3 m ongekompakteerde Avalongrond bedek is, het 'n stadige pH-daling getoon, maar het in 1997 ongeveer pH 3 bereik. Bedekkings van gekompakteerde Estcourtgrond onder ongekompakteerde A valongrond met 'n totale dikte van 1 m, was effektief in die voorkoming van suurvorming. Hulle het oor die algemeen die steenkoolafval anaerobies gehou, maar aile bedekings het tydens die droogte in 1995 krake ontwikkel, wat suurstof laat binnedring het. 'n Lae pH gedurende 1995/1996 by sommige monsters uit hierdie hope mag die begin van suurvorming aangedui het. Bakteriee wat hoe konsentrasies ferro-yster oksideer en wat as Thiobacillus ferrooxidans beskou is, was moontlik nie die dominante ysteroksideerder nie, aangesien bevolkingstellings waar 'n medium met 'n laer konsentrasie ferro-yster gebruik is, hoer bevolkings getoon het. Die meerderheid van laasgenoemde organismes kon ook nie swawel benut nie en dus nie T. ferrooxidans was nie. Die bevolkings van die hoe ferro-ysteroksiderende bakteriee is deur pH beInvloed, met 'n geneigdheid tot hoe bevolkings in suur en lae bevolkings in minder suur steenkoolafval. Ondersoeke na die rnilcrobebevollcings wat in ysteroksiderende konsortia in verryldngslculture vanaf steenkoolafval- en suur mynafloopwatermonsters voorgekom het, het die teenwoordigheid van 7'. ferrooxidans, die heterotrofe balcteriegenus Acidiphilium, fungi van die genus Penicillium, ongeIdentifiseerde fungi, insluitend Cladophialophora-agtige tipes en 'n gis van die genus Dipodascus aangetoon. By interaksiestudies het die Penicillium-isolaat 'n inhiberende effek op T ferrooxidans (onderworpe aan organiese verbindingstres) gehad, maar die Cladophialophora-agtige fungi het die inhibisie deur organiese verbindings verminder. Fungi is nog the in detail as komponente van ysteroksiderende konsortia bestudeer the, maar die isolasies van bakteried stem saam met die van elders wat aandui dat toepaslike gevolgtreldcings ten opsigte van suur mynafloopwatemavorsing vanaf ander dele van die wereld ook in KwaZulu-Natal toegepas kan word.

The landfilling of biodegradable waste is proven to contribute to environmental degradation. Much wood and lumber is discharged as waste from the cleared fields. These woody wastes are subsequently disposed of by burning. However, it would be preferable to dispose of them without combustion to avoid the release of carbon dioxide, one of the critical greenhouse gases. Instead of burning these woody wastes, we should recycle them as future resources. One solution to this problem is to make compost from the waste. Compost use in agriculture is increasing as both an alternative to landfilling for the management of biodegradable waste, as well as means of increasing or preserving soil organic matter. This research aimed to contribute to the identification of a system for managing the production and utilization of wood waste (Quercus rubra and Pinus sylvestris) compost for sustainable agriculture, with particular regards to carbon dioxide produced from both compost and combustion of wood. Compost of wood was implemented in two consecutive trials. The first was carried out in greenhouse experiment in 4 liter pot of Quercus rubra and Pinus sylvestris (QR and PS) moisted by compost and tap water and infected by tiger worm (Eisenia fetida, EF) and European night crawlers (Dendrobaena veneta, DV) at different mixed ratios with lake mud (LM). The second was conducted in greenhouse experiment in 40 liter pot of the successful wood and worm from the first compost trial (QR and EF respectively). The tested wood (QR) was mixed separately by lake mud and horse manure and irrigated by compost and tap water. The final product, successful wood compost (QR) produced from the first trial (4 liter pot) was utilized in different mixed ratios with coal mine tailings (tertiary sand) in greenhouse pot trial to study his effects on improving soil physical and chemical properties and some plant growth parameters of RSM 7.2.1 grass. The wood compost produced from the second compost experiment (40 liter pot) and other artificial component named Arkadolith® were used as soil amelioration in field experiments of different selected sites with extremely unsuitable characteristics (tertiary and quaternary sand in Lusatia lignite region, Germany). The soil in each site was sowed by RSM 7.2.1 and autochthonous grasses. Also, some vermicompost samples were selected to study its thermal stability which compared with a soil sample (Niedermoorgleys) by using thermogravimetric analysis technique. Further investigation was achieved to evaluate the effect of charcoal as a source of carbon on vermicompost stability. Moreover some selected vermicompost samples were used to examine its microstructure under scanning electron microscope which compared also with the same soil used in thermal analysis. The obtained results under all studied experiments can be arranged as follow: First compost trial, Cumulative amount of carbon dioxide produced during composting period was lower than that evolved by combustion of wood. The results showed composting of wood can reduce the emitted CO2 up to 50 % when compared with the amount of CO2 produced from combustion of wood. The effect of different studied factors on different studied parameters show that, QR wood compost have more responsive to decomposition processes and humification rate in comparison with PS wood compost. Under different infection worms, Eisenia fetida (EF) was better than Dendrobaena veneta (DV) in biodegradation rate. Compost water has had a better impact of tap water in all studied decomposition parameters. For example, The compost content of OM and total OC was decreased with the increase of the decomposition period in the treatments of compost water and EF worm, where this decrease was higher at mixed ratio of 1:3 (wood: mud, w/w). The total content of N in the final products takes reversible trend regarding to OM and C content. The high content of N was found in QR wood compost moisted by compost water and infected by EF worm. The content of both macro-and micro-nutrients was clearly positive affected by the studied factors. The content of these nutrients in QR wood compost was higher than that found in the compost of PS wood. Second compost trial, The observed data show that, the amount of CO2 produced by composting was lower than that evolved by combustion of wood. Composting of wood reduced CO2 emission up to 40 % of the combustion wood CO2. Cumulative amount of CO2 produced from wood compost treated by horse manure was higher than that fount in the other treated by LM. The compost of wood treated by horse manure has had a high decomposition rate in comparison with that treated by lake mud. The treatments left without worms during all composting period and moisted by compost water have a responsive effects but it was lower than that infected by worms. Total and available contents of N, P, K, Mg, Zn, and Cu in the compost treated by HM were higher than that found in compost treated by LM. The other nutrients (Ca, Fe, Cu, and Mn) take reversible trend, which it was higher in LM than HM treatments. Thermal and microstructure analysis, The selected vermicompost samples from both first and second compost experiments showed, up to 200° C temperature the mass loss was due to free water and bound water (It was in vermicompost samples higher than soil sample). Mass loss from 200 to 550° C is due to easily oxidizable organic forms and it was higher in vermicompost than soil. In this stage the soil OM seems to be more stable than vermicompost which can be explained by a more intensive bond between the organic and inorganic components. At higher temperatures (T> 550° C) no significant detectable was appeared of soil organic matter. In contrast, the vermicompost treatments showed a high proportion of stable groups, especially aromatic compounds. These statements seem to be importance particularly for the practical application of the wood compost in terms of their long-term effect in the soil. The application of charcoal, showed no additional stabilizing effect of vermicompost. Also, the data show that, vermicompost structure characterized with high homogeneity and ratio of surface area to volume compared to those in soil structure. First plant trials (greenhouse), Different compost mixed ratios had positive impact on different extreme soil physiochemical properties. At the end of experiment (42 days) compost increased soil water holding capacity, decreased soil bulk and particle density and increased total porosity. The used wood compost modified soil buffering capacity and soil acidity. The availability of soil macro and micro nutrients were increased after adding wood compost. The wood compost had a positive effect in some growth parameters like fresh and dry matter yield of the selected grass. High dry matter yield and nutrients uptake was achieved with higher rates of compost application (25.0% > 12.5% > 3.0% > 0.0 %, w/w). Second plant trials (field experiment), Regarding to the effect of wood compost (QR) and Arkadolith® component on tertiary and quaternary sand, at the end of grown season (6 month) most soil and plant characteristics of tertiary sand were improved and it was better than that in quaternary sand. This trend reveals to, physical and chemical properties of tertiary sand was better than that in quaternary sand, like organic matter content, CEC, WHC, TOC, available nutrients. In the both sites, the effects of different type of soil conditioners arranged as follow: the treatments treated with wood compost is the better followed by the other treated with both wood compost and Arkadolith. Wood compost increased soil pH, CEC, soil buffering capacity, OM content, and soil WHC in comparison with Arkadolith which make a small improvement of these properties in both sites. Finally, Different growth parameters (height, covering, fresh and dry matter yield) of the used grasses were clearly positive affected by wood compost, with the highest production inherent to the treatments treated by the high amount of wood compost.
Entsprechend der Zielstellung wurden zunächst verschiedene Varianten der Kompostierung von Holzsubstanz getestet, um eine optimale Technologie, die auch für Entwicklungsländer realisierbar ist, herauszufinden. Hierzu sind in Pflanztöpfe Holzspäne (Woodchips) von zwei verschieden Holzarten (Laub- und Nadelholz) gefüllt und mit verschiedenen natürlichen Stickstoffquellen gemischt worden. Diese Ansätze wurden regelmäßig mit Kompostwasser appliziert. Nach vier Wochen sind zwei verschiedene Wurmarten (Dendrobaena veneta und Eisenia fetida) hinzugegeben worden. Die Feuchthaltung erfolgte ab diesem Zeitpunkt durch Frischwasser. Die qualitativ beste Versuchsvariante ist im nächsten Schritt mit weiteren natürlichen Stickstoffquellen, die in Entwicklungsländern zur Verfügung gestellt werden könnten, getestet worden. Von allen Kompostvarianten sind im Labor eine Vielzahl von bodenphysikalischen (z.B. Dichte, Wasserhaltekapazität) und bodenchemischen Zustandsgrößen (z.B. Elektrische Leitfähigkeit, Totalgehalte biophiler Elemente, Bodenreaktion, organische Substanzgehalte, Kationenaustauschkapazität) bestimmt worden. Die Wiederum qualitativ beste Mischung ist in einer weiteren Versuchsreihe in verschiedenen Mengenverhältnissen mit tertiärerem Abraumsand des Braunkohlebergbaus gemischt worden. In diese Versuchsmischungen wurde die Grasmischung RSM 7.2.1 eingesät und regelmäßig bewässert sowie die Wuchshöhe gemessen. Nach 42 Tagen wurden das Gras geerntet und die biometrischen Parameter, die Nährstoffgehalte (pflanzenverfügbare Fraktionen), die Bodenreaktion, die effektive bzw. potentielle Kationenaustauschkapazität sowie die Pufferkapazitäten der Mischsubstrate bestimmt. Die nächsten Versuchsvarianten sind als Feldversuche in der Niederlausitz durchgeführt worden. Für ihre Realisierung wurde als weiterer Zuschlagsstoff Arkadolith® zugemischt. Die Plotflächen sind sowohl auf Abraumsanden des Tertiärs als auch Quartärs angelegt worden. In jeweils eine Subvariante ist RSM 7.2.1, in die andere eine autochthone Grasmischung eingesät worden. Diese Experimente wurden nach 6 Monaten beendet, die Bestimmung aller Parameter erfolgte in gleicher Weise wie bei den Gewächshausversuchen. Auf Basis aller Versuchsreihen konnten die besten Kompostqualitäten und ihre optimalen Herstellungsvarianten ermittelt werden. Eine weitere Aufgabe war es zu untersuchen, wie im Vergleich zur Verbrennung von Holzmasse die CO2-Emission in die Atmosphäre durch Holzkompostierung verringert werden kann. Hierzu wurde während der verschiedenen Kompostierungsvarianten die CO2-Freisetzung gemessen. Im Vergleich dazu ist jeweils die gleiche Masse an Holzsubstanz verbrannt worden. Die Ergebnisse zeigten, dass im Vergleich zu der thermischen Verwertung von Holsubstanz die CO2-Emission bis zu 50 % verringert werden kann. Dem Boden kann darüber hinaus energiereiche organische Substanz zugeführt werden, die eine Entwicklung der Bodenorganismen ermöglicht. Ein weiteres Experiment zielte darauf ab, die Stabilität der Holzkomposte zu bestimmen. Darüber hinaus sollte untersucht werden, ob durch die Zufuhr von pyrogenem Kohlenstoff eine Vergrößerung der Stabilität zu erreichen ist. Diese Untersuchungen wurden mit Hilfe der Thermogravimetrie vorgenommen. Alle wichtigen Kompostierungsvarianten sind sowohl mit verschiedenen Zusatzmengen als auch ohne Zusatz von pyrogenem Kohlenstoff vermessen worden. Als Vergleichssubstanz diente der Oberboden eines Niedermoorgleys, der naturgemäß einen relativ hohen Anteil an organischer Substanz aufweist. Die Ergebnisse zeigten, dass im Bereich niedriger Temperaturen die Wasserbindung im Naturboden fester ist. In der Fraktion der oxidierbaren organischen Substanz, im mittleren Temperaturbereich gemessen, ist die natürliche Bodensubstanz ebenfalls stabiler, was auf eine intensivere Bindung zwischen den organischen und anorganischen Bestandteilen, also auf stabilere organisch-mineralische Komplexe, schlussfolgern lässt. Im Bereich höherer Temperaturen (T> 550° C) waren im Naturboden keine nennenswerten organischen Bestandteile mehr nachweisbar. Hingegen wiesen die Kompostvarianten einen hohen Anteil stabiler Fraktionen, vor allem aromatische Verbindungen, auf. Diese Aussagen erscheinen vor allem für die praktische Anwendung der Holzkomposte in Hinblick auf ihre Langzeitwirkung bedeutsam. Der Zusatz von pyrogenem Kohlenstoff zeigte keine zusätzliche Stabilisierungswirkung.

A disposição de rejeitos com potencial de geração de acidez e consequente geração de drenagem ácida de mina (DAM) é um dos grandes problemas ambientais enfrentados pela indústria da mineração de carvão, pois a disposição inadequada contamina a água e o solo. A DAM é uma solução aquosa caracterizada por possuir pH geralmente abaixo de 3 e diversos metais dissolvidos. Devido a essas características, a DAM representa grandes riscos ambientais, em especial, aos recursos hídricos, em consequência da solubilização e mobilização de metais pesados. Este problema requer estudos no sentido de encontrar soluções que venham a minimizar os danos causados ao meio ambiente. A utilização de metodologias alternativas para a disposição dos rejeitos de mineração de carvão constitui em uma estratégia básica para a viabilidade de tais empreendimentos. Visando atender a esta necessidade, o presente trabalho estudou o controle da geração da DAM pelo método de aditivos alcalinos com o uso de escória de aciaria elétrica do forno panela (EAE-FP). A metodologia do trabalho incluiu a caracterização dos materiais, ensaios estáticos e ensaios cinéticos. Os ensaios estáticos foram realizados pelo método de contabilização de ácidos e bases, enquanto que os ensaios cinéticos foram realizados pelo método de células úmidas. Após foi realizada a mistura do rejeito de carvão com a EAE-FP em diferentes dosagens e foram dispostas a céu aberto, sujeitas à precipitação pluviométrica. Esses ensaios tiveram por objetivo uma melhor compreensão dos materiais em ambiente controlado e expostos ao intemperismo. Os resultados demonstram que a água que percolou pelo rejeito de carvão apresentou-se ácida e a água que percolou pela EAE-FP, alcalina. Contudo, os problemas ambientais podem ser em grande parte resolvidos pela mistura do rejeito de carvão com EAE-FP em uma proporção de RC:EAE-FP 10:10 estabelecida pelos ensaios estáticos. Os ensaios cinéticos e o experimento ao ar livre demonstram que durante vários meses de ensaios, na proporção RC:EAE-FP 10:10, ocorre um aumento do pH e uma redução na liberação de acidez, metais e sulfatos na água lixiviada. Análises adicionais de toxicidade para o microcrustáceo (Daphnia similis), peixes (Pimephales promelas) e algas (Pseudokirchneriella subcapitata) mostraram que o lixiviado da proporção RC:EAE-FP 10:15, apresentou níveis menores de toxicidade do que o lixiviado da proporção RC:EAE-FP 10:10, além da redução na liberação da acidez, metais e sulfato. Os resultados demonstraram a eficácia do método na qualidade da água de percolação tanto em termos de pH, concentrações de metais e toxicidade do efluente. Pode-se concluir que o método de contabilização de ácidos e bases mostra-se adequado para definir a proporção de mistura dos materiais. Essas misturas podem ser empregadas no controle da DAM tanto em depósitos de rejeitos em superfícies como no retorno dos rejeitos de carvão para o subsolo.
The waste disposal with potential to generate acidity and consequent generation of acid mine drainage (DAM) is one of the major environmental problems facing the coal mining industry since the improper disposal contaminates water and soil. DAM is an aqueous solution characterized by having pH below 3 and typically many dissolved metals. Due to these characteristics, the DAM is major environmental risks, especially to water resources as a result of solubilization and mobilization of heavy metals. This problem requires studies to find solutions that will minimize damage to the environment. The use of alternatives for the disposal of tailings coal mining methodologies constitutes a basic strategy for the viability of such projects. Aiming to address this need, this paper studied the control of the generation of DAM by alkali additives method with the use of the ladle slag of electric steelmaking (LSES). The methodology of the study included the characterization of materials, static tests and kinetic assays. The static tests were performed by the recording method of acids and bases, while kinetic assays were performed by the method of wet cells. Upon mixing coal tailing was performed with the LSES in different dosages and were placed in the open, subject to rainfall. These tests were aimed at a better understanding of the materials in a controlled environment and exposed to weathering. The results demonstrate that water leached by coal waste is introduced and acid leached by water LSES alkaline. However, environmental problems can be largely solved by mixing the coal waste with LSES in a ratio of CW:LSES 10:10 established by static tests. Kinetic assays and outdoor experiment demonstrate that several months of tests, the ratio CW:LSES 10:10, there is an increase in pH and a reduction in the release of acidity, metals and sulphate in the leach water. Further analysis of toxicity microcrustacean (Daphnia similis), fish (Pimephales promelas) and algae (Pseudokirchneriella subcapitata) showed that the proportion leached CW:LSES 10:15, showed lower levels of toxicity than the proportion of leached CW:LSES 10:10, besides the reduction in the release of acidity, metals and sulfate. The results demonstrated the effectiveness of the method on the quality of percolating water in terms of pH, metal concentration and toxicity of the effluent. It can be concluded that the method of recording of acids and bases proves to be adequate to set the mixing ratio of the materials. These blends can be used to control both DAM tailings deposits on surfaces such as the return of waste coal underground.

Includes bibliographical references.
Acid mine drainage (AMD) is one of the major environmental challenges facing the South African mining sector. Acid mine drainage has received significant public attention in recent years. South Africa's long mining history has led to a growing concern that coal-related AMD from these mines (both operational and defunct) will continue for centuries to come. Pyrite bearing fine waste, generated during coal preparation and beneficiation, is thought to carry a significant amount of AMD pollution risk. Coal-related AMD generation has not been afforded the same exposure as AMD generation from high sulphide minerals such as gold and copper ores. This is exacerbated by the growing concern over water quality degradation in the Mpumalanga region of South Africa. The development of integrated solutions to address the management of coal-related AMD requires an understanding of the principle causes behind coal-related AMD. To date, most of the prediction methods described in literature have been derived for the prediction of AMD in metal bearing ores. Furthermore, some of these methods are based on assumptions and do not take into consideration the various sulphur species present. Additionally, some of these methods have limited applicability to coal due to the high total organic carbon content (TOC) of the material. This research project attempts to address these short comings and uncertainties by developing a systematic and meaningful framework for the characterisation of South African coal and coal waste. The research project contributes to the knowledge of coal-related AMD with particular emphasis on the characterisation methods responsible for sulphur speciation and mineralogy for coal. The approach entails carrying out a case study assessment aimed at empirically assessing a coal tailings sample according to: particle size distribution, textural reference, mineralogical characteristics, and how the aforementioned factors influence the acid potential in coal. The approach intends to address key factors which include: identifying the sulphur bearing organic and inorganic constituents related AMD generation in coal, assessing how the mineralogy, texture and particle size distribution contribute to AMD potential in coal tailings, and then identifying suitable analytical techniques and test methods which can provide data. The combination of these key outcomes will seek to provide a systematic and meaningful framework for the characterisation of coal and coal waste streams. The characterisation methods used in this case study outlined a framework focusing on four main areas of acid mine drainage characterisation for coal wastes, these included: chemical characterisation, mineralogical characterisation, sulphur speciation and AMD prediction. This comprehensive approach employed a suite of techniques, including: petrography, quantitative x-ray diffraction (QXRD) and quantitative evaluation of minerals by scanning electron spectrometry (QEMSCAN).

The depletion of more attractive thicker and easily accessible coal seams in the central Appalachia will direct attention towards the extraction of coal seams thinner than 28 in. This thesis investigates the feasibility of an integrated mining and backfilling system applicable to thin seams. Two conceptual mining systems, namely Auger mining and Self Advancing Miner, have been proposed for this purpose. Both these systems are designed to remotely mine coal from the seams. Several attempts were made in the past to mine coal in a similar fashion but were not very successful due to several problems inherent to thin seams. The lack of effective steering techniques, accurate coal/rock interface and pillar thickness detection techniques were the main shortcomings of the systems. These problems were addressed in the proposed conceptual mining systems. Several coal/rock interface and rib thickness detection techniques currently available in the market or in the prototype stage have been discussed. Recent developments in coal/rock interface detection and direction sensing techniques have good potential in alleviating the previously encountered problems. Sensitivity analyses have been performed to assess the of effect critical mining parameters on the production potential of these systems. The self advancing miner has been found to be more promising than auger mining. Conceptual panels and face layouts for both systems have been included. Two types of filling methods namely pneumatic and hydraulic are considered applicable under thin seam conditions. A backfilling technique using rubber hoses for fill placement can be applied with both methods. Sensitivity analysis have been performed to establish the relationship between face operation cost, filling cost per ton and development cost per foot. Resulting analyses indicate that panel cost per short ton of coal is more sensitive to filling cost than on development cost.
Master of Science

The production of acid mine drainage (AMD) is catalyzed by iron-oxidizing bacteria primarily of the species Thiobacillus ferrooxidans. By inhibiting these bacteria, the production of AMD can be greatly reduced. One compound found to be effective in the inhibition of T. ferrooxidans is nitrapyrine. N-Serve, a product of Dow Chemical, Inc., is the commercially available form of nitrapyrine. This compound has been widely used in agriculture for nitrification inhibition. The purpose of this study was to determine the effectiveness of N-Serve in reducing the production of AMD under simulated field conditions. A column study was completed using a coal mine waste and a hard-rock mine waste. Eight columns containing 7kg of rock were established for each substrate. Three doses of NServe (22% nitrapyrine) were applied once at the beginning of this study: a high dose 2200 mg/kg, a medium dose 220 mg/kg, and a low dose 22 mg/kg. Duplicate columns were included for each N-Serve dose including two untreated columns to serve as a control for each substrate. Beginning the week after treatment, the columns were leached once a week for 29 weeks with deionized, distilled water (equivalent to 2.5 cm precipitation). Only the highest NServe dose produced a column leachate of significantly better quality than that of the controls. The acidity in the high-dose coal mine columns averaged less than 50 percent of the acidity in the control effluent from week 6 through the end of the study. A monolithic controlled release system utilizing acrylonitrile rubber was successfully developed and tested for use with nitrapyrine. This formulation should withstand the rigors of the environment and with minor modification could produce a variety of release rates.
Master of Science

Coarse coal refuse is difficult to reclaim due to high potential acidity and coarse fragment content, low water holding capacity, low fertility, and other problems. Little is known about coal refuse properties, particularly as they relate to revegetation potential. This study was undertaken to determine the physical and chemical properties of composite samples from 27 coal waste piles of varying age. Selected physical and chemical properties varied widely across this sample set. The mean coarse fragment (>2mm) content of these materials was 60%. The average texture of the fine (<2mm) fraction was a sandy loam with 15% clay. The mean water retention difference, between 0.03 MPa and 1.5 MPa of soil moisture tension, on a whole sample basis was 0.08 g water/g refuse. The pH values varied from 8.3 to 3.0, and the older piles generally had lower pH values than the more recent piles. The saturated paste electrical conductivity (EC) was higher in the younger coal waste materials. Total elemental analysis revealed that Si, Al, Fe, and K were the most abundant elements in these materials. The mineralogy of three selected samples was found to be dominated by quartz in the sand and silt fraction and mica in the clay fraction. The physical factor most limiting to plant growth was found to be low water holding capacity. Low pH was found to be the chemical factor most limiting to plant survival. These findings indicate that some refuse piles may be suitable for direct seeding, but many will require heavy lime and/or organic treatments.
Master of Science

Today, solid waste management in coal mines is an urgent requirement for the coal mining industry. The overlying materials removed from a seam of coal are solid wastes transported to dumping sites and should be strictly, efficiently managed and monitored by an automatic system. These wastes must be separated for use as leveling and filling materials or residue materials need to be processed in order to minimize the impact on the environment. The system was designed to manage and monitor vehicles transporting solid waste in open coal mines to force them in tasks of taking solid wastes and giving out these wastes in the right places, to help collect and process suitably. The results showed that the calculation of numbers of trips using the software program named "Management of trucks" achieved the statistics of running trucks between the points of removing wastes and dumping sites, in which the numbers of valid and invalid trips were given out. The monitoring process obtained the statistics of active and inactive total time of vehicles transporting solid waste. From that we can calculate and classify them at each dumping site. In addition, the statistics of productivity of power-shovels, fuel consumption levels of excavators and trucks were also gained
Hiện nay quản lý chất thải rắn tại các mỏ than là một yêu cầu cấp bách đối với ngành khai thác than. Các chất thải khi bóc vỉa được chở đến các bãi đổ cần có một hệ thống quản lý giám sát chặt chẽ. Những chất thải này phải được phân loại để làm vật liệu san lấp hoặc vật liệu cần xử lý nhằm giảm thiểu các tác động tới môi trường. Hệ thống được thiết kế có nhiệm vụ quản lý và giám sát các xe chở chất thải trong quá trình khai thác tại các mỏ lộ thiên, đảm bảo các phương tiện này được xúc và đổ đúng nơi quy định, giúp thu gom, xử lý một cách phù hợp. Kết quả cho thấy rằng việc tính toán số lượng các chuyến xe bằng cách sử dụng chương trình phần mềm có tên là "Quản lý xe tải" thu được các số liệu thống kê xe chạy giữa các điểm xúc chất thải và các điểm đổ, trong đó thống kê được số lượng các chuyến đi hợp lệ và không hợp lệ. Quá trình giám sát thu được các số liệu thống kê của tổng thời gian hoạt động và không hoạt động của các phương tiện vận chuyển chất thải rắn. Từ đó chúng tôi có thể tính toán và phân loại chúng ở mỗi điểm đổ chất thải. Ngoài ra, cũng thu được các số liệu thống kê năng suất hoạt động của máy xúc, mức tiêu thụ nhiên liệu của máy xúc và xe tải

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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Дисертаційна робота присвячена дослідженням підтериконових стічних вод із породних відвалів вугільних шахт Нововолинського гірничопромислового району, аналізу системи заходів з метою підвищення екологічної безпеки гірничопромислового комплексу на довкілля. Встановлення рівнів екологічної небезпеки стічної води із відвалів вугільних шахт, дослідження сезонної динаміки вмісту важких металів стічної води з териконів, проектування та розрахунок біоплато дозволяють запровадити новітні форми очищення стічних вод із відвалів вугільних шахт та сприяють підвищенню екологічної безпеки регіону. У результаті проведених досліджень проб води зафіксовано підвищення вмісту солей амонію. Як відомо, головна небезпека забруднення гідросфери солями амонію полягає у перенасиченні води амоніаком. Вміст амонійних солей вище 0,1 мг/дм3 свідчить про свіже забруднення води, адже амоніак є першою сполукою, що утворюється в процесі розкладу органічних нітрогеновмісних речовин. Одночасний вміст у пробах води амоніаку, нітритів та нітратів, сульфатів, гідрокарбонатів свідчить про значну забрудненість підтериконових стічних вод через окиснення породи у відвалі та її вимивання водою. Підвищення в пробах води вмісту нітритів та нітратів без виявлення амоніаку свідчить про ізоляцію джерела забруднення. Аналізуючи стан екологічної ситуації в результаті розливання стічних вод з технологічних відвалів шахт №: 2, 4, 9 Нововолинського гірничопромислового району слід відмітити, що на даний час зливова каналізація на досліджуваних шахтах відсутня, тому дощові води із поверхонь породних відвалів та промислових майданчиків стихійно стікають у низовини на місцевості та концентруються мінеральними солями. Відомо, що для шахт цього району властиві значні водоприпливи в головні та підготовчі гірничі виробки, тому утворені стоки периметром існуючих відвалів збирають у водовідвідні канави. Встановлено причини та наслідки зростання рівня екологічної небезпеки угірничопромислових комплексах; сезонну динаміку вмісту хімічних речовин в підтериконових стічних водах із шахтних териконів; вміст важких металів у стічних водах та рослинності; запропонований науково обґрунтований розрахунок біологічних ставків для очищення стічних вод та заходи подолання негативного впливу техногенного забруднення стічних вод на біоту; за допомогою ГІС-проєкту “Open Environment” здійснено аналіз якості водних об’єктів досліджуваного регіону. Геоінформаційна інтерактивна карта побудована на базі статистичних даних Державного агентства водних ресурсів України та даних супутникових спостережень. Показники якості води підтверджують той факт, що поряд із вітровою ерозією териконів, дослідженню якої приділена велика кількість наукових робіт, гостро стоїть питання саме водної ерозії териконів, яка призводить до вимивання токсичних полютантів і забруднення ними ґрунту та підґрунтових вод. Забруднення поширюються із підтериконовими водами на значні відстані прилеглих територій, зокрема на поверхневі води басейну р. Західний Буг. Dissertation is dedicated to the research of wastewater from waste heaps of coal mines of Novovolynsk mining area, analysis of the measures system to increase the environmental safety of the mining complex. Establishing the levels of environmental hazard of wastewater from coal mine dumps, investigation of the seasonal dynamics of heavy metals content in wastewater from waste heaps, design and calculation of bioplates gives an opportunity to introduce the advanced technologies for treatment of wastewater from mine waste heaps and improve environmental safety of the region. As a result of water samples analysis, an increase in the content of ammonium saltswas determined. It is known that the main danger of pollution of the hydrosphere with ammonium salts is the supersaturation of water with ammonia. The content of ammonium salts above 0.1 mg/dm3 indicates the water pollution, because ammonia is the first compound formed during the decomposition of organic nitrogen-containing substances. Simultaneous occurrence of ammonia, nitrites and nitrates, sulfates, bicarbonates in the water samples indicates a significant contamination of wastewater due to oxidation of the rock in the dump and its leaching with water. An increase of nitrites and nitrates content in water samples without ammonia indicates the isolation of the source of contamination. Analyzing the ecological situation as a result of spillage of wastewater from dumps of mines №: 2, 4, 9 of Novovolynsk mining area it should be noted that currently storm sewer system is absent there, so rainwater from the surfaces of waste heaps and industrial sites spontaneously drain in lowlands and concentrates by mineral salts. It is known that the mines of this area are characterized by significant inflows into the main and preparatory mine workings, so the formed effluents around the perimeter of the existing dumps are collected in water diversion channels. The causes and consequences of the growth of environmental hazard level in mining complexes, seasonal dynamics of the chemicals content in wastewater from mine heaps, heavy metals content in wastewater and vegetation were established; scientifically substantiated calculation of biological ponds for wastewater treatment and measures to overcome the negative impact of man-made wastewater pollution on biota were suggested; by applying the GIS project "Open Environment" the analysis of the water body quality of the area was carried out. The geoinformation interactive map is built on the basis of statistical data of the State Agency of Water Resources of Ukraine and data of satellite observations. Water quality indicators confirm the fact that besides the wind erosion of waste heaps, the water erosion of waste heaps is of a high concern, which leads to leaching of toxic pollutants into soil and groundwater. Pollution spreads with wastewaters over long distances of adjacent territories, in particular to the surface waters of the Western Bug basin

Acid rock drainage (ARD) is recognised as one of the most serious environmental issues currently facing the mining industry. ARD management strategies rely heavily on the ability to measure the ARD potential of waste materials to ensure strategies are appropriate to the ARD risks. It is apparent that improvements to the understanding of ARD test methods and development of methods to better represent the ARD potential of samples will contribute significantly to the value and reliability of ARD assessment. The research described in this thesis focused on critical assessment and improvement of: ARD test methodology; approach to testing; and interpretation of results for coal mine wastes. Kaltim Prima Coal Mine (KPC) in Kalimantan, Indonesia was selected as a case study site to help focus the research, with the understanding that the broad similarities of coal sequences in general would allow broader application of the findings.
Thesis (PhDApSc(MineralsandMaterials))--University of South Australia, 2005

Research Doctorate - Doctor of Philosophy (PhD)
After drilling to establish the hottest part of a coal mine spoil pile, two stainless steel thermosyphons were installed to assess their ability to cool the hot ground. One device was a single-phase coaxial thermosyphon (water down through the outer annulus) with forced circulation, and the other was a two-phase (liquid plus vapour) device that relied on thermal buoyancy. The heated mine spoil into which the devices were installed was found to have experienced combustion that had since ceased, leaving a localised hotspot. Natural ground cooling was found to be unexpectedly rapid and exacerbated by the intrusion of a water table. After 36 successful pumped trials, performed over 14 months, the study found that neither device could significantly affect ground temperature, and that any cooling they could achieve was insignificant compared to the background cooling at the site. Also, the single-phase thermosyphon was ineffective at reheating cooled water when operated continuously; consequently the rate of energy extraction was not useful. Further, the heat extraction potential was so limited that it did not exceed the unintended losses from the aboveground system elements, so most acquired heat was unintentionally lost. The combination of vertical, lateral and temporal ground temperature variations made interpretation of the data difficult and rendered the devices ineffective. Vertical stratification of ground heat meant a significant amount of the heat acquired by the device was redistributed before it could be brought to the surface. The study concludes that given the limited fuel in the waste, the rapid natural ground cooling, and the ineffectiveness of either type of device to remove heat, there is little to be gained in trying to extinguish fire in waste piles when it occurs.

The discharge of coal mine generated wastewater has degraded the Georges River downstream of the discharge point. This study measured the water quality, sediment quality and macroinvertebrate community of the upper Georges River to determine the impact of the influx of wastewater from an underground coal mine. The investigation revealed that the wastewater discharge from the West Cliff Colliery into the Georges River was highly polluted. The pollution of the river is characterised by increases in electrical conductivity, pH levels and a suite of metals including antimony, aluminium, arsenic, barium, boron, cobalt, lithium, molybdenum, nickel, strontium, titanium, uranium and zinc. The elevated concentrations of metals downstream of the wastewater discharge point has caused a suite of metals including; aluminium, barium, chromium, cobalt, copper, iron, lead, lithium, manganese, nickel, strontium, titanium, uranium and zinc to accumulate within the sediment. The altered water chemistry downstream of the wastewater discharge point is expected to be the salient factor in the significant loss of biodiversity within the macroinvertebrate community. The aquatic macroinvertebrate community downstream of the wastewater discharge is characterised by a loss of pollution sensitive taxa and an increase in pollution tolerant taxa. A laboratory experiment has identified that a suite of metals including; aluminium, boron, barium, cobalt, copper, iron, lithium, manganese, molybdenum, nickel, strontium and uranium present in the coal mine wastewater discharge are able to bioaccumulate within plants that are exposed to the wastewater. This research has demonstrated that the current implementation of environmental protection legislation has failed to protect one of Sydney’s major waterways from the effects of coal mining. Consequently, it is essential that we better manage our aquatic ecosystems to avoid further instances of degradation and to preserve ecosystem functions and services.

The South African coal industry produces a large quantity of coal per annum. The rejects from various unit operations, such as spirals, consist of fine coal that joins the plants tailings dam waste. As existing high quality resources become depleted, the need to improve recovery of this fine coal grows. This project investigates the use of a teetered bed separator (TBS); a hindered settling gravity concentration device for fine coal recovery. This device has proven successful in the United Kingdom and in Australian collieries for fine coal separation in the size range between 2mm and 0.3mm. It has also been used for decades as a classifying device for silica sand and tin. The TBS operates in the size range of water-only cyclones and spiral concentrators, and could potentially be used to separate a broader size range of coal fines so as to offer a lower footprint device for the fines recovery section of a plant. Spiral concentrators cannot always be operated efficiently at a separating specific gravity of lower than 1.6; a TBS may also extend the density range for separation and thus improve recovery. The objective of this project was to gain a full understanding of the TBS from fundamental particle interaction and develop a lab scale unit, which is capable of separation to about 0.1mm at optimum conditions. This involved the development of design parameters based on the various distributor plates and flow pattern modelling. The hydrodynamics of the separator were investigated using the Eulerian-Eulerian modelling approach of commercial CFD package, Fluent 6.1. Seven distributor plates of varying aperture size and geometric arrangement were considered. Coal and shale particles, sized between 2mm and 0.038mm with a specific gravity (SG) range of 1.2 to 2.0, were separated using the laboratory scale unit. The results of both the simulations and the laboratory tests were then compared. The simulations revealed that Plate 3 was the best option for implementation. It had an even upward velocity profile compared to the other plates, with minimum wall effects and disturbances. The upward water flow rate (teeter water) was varied experimentally and the composition of the teeter bed, underflow and overflow were analysed using 1.5, 2 and Smm cubic density tracers with an SG range of 1.2-2.0. Analysis of the partition curves of the distributor plates revealed that Plate 3 had the lowest Ecart Probable (Ep) and cut- point densities. The comparison of simulated results and experimental results show that the simulator could predict the distributor plate design with the lowest Ep in practical tests. The simulator could be beneficial when optimising an industrial scale unit, by allowing prediction of improved segregation patterns and thus separation efficiency.
Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2005.

Waste rocks (WRs) from coal mining and fly ash (FA) from coal combustion were studied to determine the potential of the WRs to generate AMD, FAs to neutralise it and estimate their impacts on environment. The ultimate goal was to develop a methodology based on co-disposal to mitigate the environmental problems associated to both wastes. Two methods for co-disposal were tested: i) Mixing WRs and FAs and ii) covering WRs with FAs. WRs were sampled from the Lakhra coal mines in Pakistan (PK), which has an estimated coal reserves of 1.3 Btonne, varying from lignite to sub-bituminous quality. The FA was sampled from a power plant utilising coal from Lakhra coal mines and is situated in close vicinity (15km) of the mine site. For comparative purposes a bituminous FA from Finland (FI) and biomass FA from Sweden (SE) were also characterised. The WRs and FA samples were characterised by mineralogical and geochemical methods. Besides organic material (coal traces), quartz, pyrite, kaolinite, hematite, gypsum and traces of calcite, lime, malladerite, spangolite, franklinite and birnessite were identified in WRs by XRD. The major elements Si, Al, Ca and Fe were in the range (wt. %) of 8 – 12, 6 – 9, 0.3 – 3 and 1 – 10, respectively, with high S concentrations (1.94 – 11.33 wt. %) in WRs. The AMD potential of WRs ranged from -70 to -492 kg CaCO3 tonne-1. All FAs contained quartz, with iron oxide, anhydrite and magnesioferrite in PK, mullite and lime in FI and calcite and anorthite in SE. The Ca content in SE was 6 and 8 times higher compared to PK and FI, respectively. FAs were enriched in As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn compared to continental crust. The acid neutralising potential of PK was equivalent to 20 kg CaCO3 tonne-1 compared to 275 kg CaCO3 tonne-1 (SE) and 25 kg CaCO3 tonne-1 (FI). During the period of 192 days in weathering cell experiments (WCE), the pH of leachates from most acidic WRs was maintained from 1 to 2.5, whereas, the less acidic WRs produced leachates of mildly acidic (2.7) to neutral (7.3) pH. The leachates from very acidic WRs ranged in the concentrations of Fe, SO24− and Al from mg L-1 to g L-1. The samples were subjected to column leaching experiments (CLE) in which mixture (FA:WR; 1:3) and cover (FA:WR; 1:5) cases were mimicked (with 10mm particle size) and effects of particle size (2, 5 and 10mm) on element leaching were studied. Despite having the lowest acid-neutralisation potential compared to FI and SE, co-disposal of PKFA as mixture readily provides acid buffering minerals, resulting in better start-up pH conditions and leachate quality. However, acidity produced by secondary mineralisation contributes towards the acidification of the system, causing stabilisation of pH at around 4.5−5. Secondary mineralisation (especially Fe- and Al-mineral precipitation) also removes toxic elements such as As, Pb, Cu, Zn, Cd, Co, Ni and Mn, and these secondary minerals can also buffer acidity when the pH tends to be acidic. In contrast, the pH of the leachates from the PKFA cover scenario gradually increased from strongly acidic to mildly acidic and circumneutral along with decrease in EC and elemental leaching in different WRs. Gradually increasing pH can be attributed to the cover effect, which reduces oxygen ingress, thus sulphide oxidation, causing pH to elevate. Due to the fact that pH~4–5 is sufficient for secondary Fe- and Al-mineral precipitation which also removes toxic elements (such as Cd, Co, Cu, Zn and Ni) by adsorption and/or co-precipitation, the FA cover performs well enough to achieve that pH until the conclusion of the CLE. However, due to the slower reactivity of the buffering system (additional to the initial flush-out), leaching in the beginning could not be restricted. The co-disposal of FA as cover and/or mixture possesses potential for neutralisation of AMD and improving leachate quality significantly. Particle size of the WRs affected the leaching of the sulphide related elements (such as Fe, S, Zn, Co, Cr, Cu, Mn and Ni) in CLE and WCE. Experiments with ≤1mm particle size constantly produced acidic and metal laden leachates. Co-disposal of FA and WRs as cover and mixture need to be investigated on pilot-scales before full-scale application.

Seepage from steelmaking coal mine waste rock dumps in the Elk Valley, British Columbia, Canada can contain selenium (Se), cadmium (Cd), and sulfate (SO42-) from the oxidation of sulfide minerals, and nitrate (NO3-) from blasting. The impact of these constituents of interest (CIs) on receiving groundwater systems and the potential for their natural attenuation is investigated. A 10.7 km2 mine-impacted research catchment (West Line Creek) was instrumented with 13 monitoring wells and 8 drivepoint wells to characterize the hydraulics and geochemistry of the aquifer system downgradient of the waste rock dump. These data were augmented with geophysical surveys and by characterizing the lithology, geotechnical properties, and geochemistry of core samples obtained during drilling. Furthermore, the groundwater monitoring program also facilitated the development of a conceptual model of hydrogeology in a small montane valley. An unconfined aquifer at the overburden/fractured bedrock interface, i.e. the basal alluvial aquifer was identified as the primary groundwater conduit for the migration of water and solutes from the waste rock dump toward Line Creek. Vertical and horizontal dispersion of CIs was confirmed with porewater analysis of core samples, with Se concentrations exceeding the BC water quality guideline (2.0 µg/L) in 98% of samples (n = 223). Residence time for groundwater in the overburden aquifers was determined using 3H/3He age dating (n = 3) and estimates of groundwater velocity to be less than three years across the 650 m study site. The chemistry of groundwater was compared with rock drain water samples to evaluate CIs from their source through to identified discharge locations. Linear correlation of CI concentrations with SO42- concentrations in water samples showed that Se and NO3- were conservative solutes, whereas Cd was non-conservative and may be undergoing mineral precipitation or adsorption reactions in the groundwater system. The distribution of CIs in the overburden aquifers was seasonally variable and dilution was determined to be the dominant mechanism controlling the concentrations of conservative CIs (Se, SO42- and NO3-) away from the toe of the waste rock dump and during the spring freshet. The basal alluvial aquifer downgradient of the waste rock dump was estimated to annually discharge 16% of the water and 7% of the SO42- load from the catchment.

Environmental regulation and licencing of coal mine wastewater discharges are often ineffective at achieving the core objective of protecting environments from negative impacts such as water pollution. Coal mining and the discharge of mine wastewater to river systems is a widespread source of water pollution across the world, often introducing ecologically hazardous levels of salinity and contaminants such as the heavy metals nickel and zinc. Many discharges of mine wastewater to the environment are not appropriately regulated, often resulting in the degradation of water quality and aquatic macroinvertebrate communities. Conditions of environmental regulation that are conducive to protecting water quality and river ecology in streams receiving wastewater have not been fully explored. This thesis explores the role of different environmental regulation conditions on water quality and river health across the Bargo River, Nepean River, and Wollangambe River in NSW, Australia, and investigates which conditions lead to effective or ineffective environmental regulation. The results from this thesis can be applied to improve the effectiveness of environmental regulation and to reduce water pollution impacts in rivers receiving coal mine and other industrial wastewater discharges.

MESMEG
Department of Mining and Environmental Geology
The Mushithe coal occurrence is situated approximately 16 km west of the Tshikondeni coal mine in the Tshipise-Pafuri sub-basin of the Soutpansberg coalfield in South Africa. The Soutpansberg Coalfield has received comparatively less attention compared to other more notable South African coalfields. There is as a consequence very limited information in the public domain applicable to the geology as well as quality of coal in this coalfield, as a result there is no known study focused exclusively on the Mushithe coal occurrence. The aim of the study was to conduct detailed geological mapping of the Mushithe Deposit so as to ascertain the geological environment and petrological characteristics of rocks within the area. Further work involved coal sampling and analysis in order to establish coal quality and its physical and chemical characteristics. Samples were collected using geological field mapping and channel sampling. Nine coal samples were collected from the coalbed and host rock, exposed along the Mbodi River, during geological field mapping using channel sampling. Furthermore, 92 rock samples were collected during geological field mapping of which 10 representative samples were selected for further analysis. X-ray fluorescence spectrometry was conducted on all selected samples. Proximate analysis and ultimate analyses, and calorimetry tests were undertaken on coal samples. Three samples were selected based on calorific value for maceral identification, mineral analyses and vitrinite reflectance using petrographic study. Detailed geological mapping of the area around the Mushithe coal occurrence showed the geological setting of coal in this area. The following lithologies were identified in the study area: sandstone, mudstone, ironstone, calcrete, shale, quartzite, quartz vein with a general strike direction to the north-east. The host rocks including coal were intruded by dolerite dykes and this resulted in the devolatilization of coal. The current study concluded that the Mushithe coal was formed in a wet swampy environment. This has been confirmed based on tissue preservation index (1.69) and gelification index (2.35). Coal rank ranged from bituminous Rank C- B according to United Nations Economic Commission for Europe Coal Classification (UNECE) and samples were characterised by high ash (27.90%), high moisture (10.47%) and low sulphur (0.24%). Furthermore, coal was graded below grade D based on classification for use by ESKOM which consider any calorific value below 24.5 MJ/kg to be in this category. The coal is vitrinite rich (77.75 vol%) and low in Inertinite (22.25 vol%) and devoid of Liptinite and pseudovitrinite, thus it is of good coking quality. Geochemical analysis revealed that the coal was enriched in TiO2 and Fe2O3 which was corroborated by the mineral matter which was mostly clay and pyrite. Comparatively, coal quality analysis revealed the calorific value of 14.26 MJ/kg and vitrinite reflectance between 0.94 %ROV to 1 %ROV which was less than that of the Tshikondeni Deposit but greater than that at Waterberg coalfield. The study recommends further detailed exploration of coal in the area, applying such techniques such as geophysical exploration and borehole drilling leading to resource evaluation. Further studies are recommended to provide a better interpretation of the depositional environment of coal at Mushithe as well as the effect of devolatilaziton by a dolerite dyke.
NRF

This research surveys water quality and chemistry, river sediment chemistry and aquatic macroinvertebrates in eight streams that are the recipient of coal mine wastewaters from seven collieries across the Sydney Basin. The study also surveyed water quality and chemistry at five of the seven collieries wastewater discharge streams (effluent streams). Most of the coal mine wastewater discharges are licensed and regulated by the New South Wales Environment Protection Authority (NSW EPA) through a series of Environmental Protection Licences (EPL’s). During this study four of the collieries were actively mining ore, while three were inactive. One of these had permanently ceased mining more than 20 years previously. Results revealed that all seven mines caused mild to significant modifications to a plethora of water quality and water chemistry parameters, river sediment chemical parameters and macroinvertebrate community structure. Many of the pollutant concentrations recorded in this survey were above, or outside of their respective ANZECC 2000 guidelines for protection of aquatic ecosystems. pH and salinity (electrical conductivity) were often above the recommended guidelines and substantially differing from their background conditions. Of widespread concern are the elevated concentrations of the metals nickel and zinc, with the majority of samples collected from coal mine wastewater streams and downstream of their inflow to rivers well above the recommended ANZECC 2000 guidelines. Iron and manganese were also found to be of elevated ecological concern with aluminium, cadmium, chromium, copper and lead also often above the recommended ANZECC 2000 guidelines for protecting ecosystems. Macroinvertebrates were collected from upstream and downstream of all eight mine wastewater discharges to measure the impact of the coal mine wastewaters on aquatic ecosystems. Results of the study show that the coal mine wastewaters being discharged were having varying negative impacts to the receiving waterways aquatic ecosystem that this research quantified through assessment of aquatic macroinvertebrates. The findings of this research have revealed major flaws in the current environmental regulation of seven licenced coal mine wastewater discharges within the Sydney Basin. This comprehensive research has shown that at many levels the current NSW EPA water pollution regulation of the seven coal mines fails to protect the downstream waterway from the pollution. The NSW EPA regulation of coal mine wastewaters focus on the waste attributes at the ‘end-of-pipe’ waste discharge. Along with the NSW EPA method of “monthly focus” on a selection of colliery wastewater pollutant concentrations, these approaches do not fully take into account the impact of the waste discharges on the receiving waterways aquatic ecosystems.

A series of pot trials were undertaken to test the growth of indigenous grasses (Themeda triandra and Cynodon dactylon) on mine capping soil, treated with various soil ameliorants. The capping soils were obtained from open cast coal mines (Optimum Mine and Syferfontein Mine) in the Mpumalanga Highveld, south of Witbank. However, because mine soil was not available at the commencement of the project, the initial pot trial used soil from the Umlazi Landfill in Durban. The trials were the Umlazi Landfill Trial, Microbe Trial, Legume Trial and Fly Ash Trial. For the Umlazi Landfill Trial, landfill top and subsoil was used along with fertilizer, sewage sludge, K-humate, lime and microbes. The soil ameliorant treatments for the Microbe trial were Trichoderma harzianum (Eco'T), Bacillus subtilis Strain 69 (B69) and Bacillus subtilis Strain 77 (B77), for the Legume Trial, Medicago sativa, phosphorus and/or potassium were applied. For the Fly Ash Trial, lime and fly ash were introduced. From the Landfill trial it was shown that fertilizer and sewage sludge significantly increased the above ground, below ground and total biomass of T. triandra, further, there were no significant treatment differences between fertilizer and sludge. The lime treatment for this trial, surprisingly, significantly reduced below ground biomass but the application of microbes (B69 and BcoT) alleviated this negative effect. However, in the Microbe Trial the microbes (BcoT, B69 and B77) had a negative or no effect on the biomass of T. triandra and C. dactylon. In the Legume Trial it was shown that the above ground biomass of T. triandra was significantly reduced when grown with M. sativa. The Fly Ash Trial revealed that the lime and fly ash treatments had no effect on the biomass of M. sativa and T. triandra, and they did not maintain a reduction in soil acidity. The results therefore indicated that either organic fertilizer or sewage sludge could be used to significantly improve the growth of T. triandra. It was also suggested that lime not be applied to soils with an acid saturation of approximately 1%, as this could retard plant growth. The application of microbes and the growth of a legume with grass, although both have been recorded to have beneficial effects in aiding plant growth, in the short-term however, the application of T. harzianum, B. subtilis Strain 69 and 77 applied to the soil while growing T.triandra and C. dactylon and the growth of M. sativa with T. triandra is not recommended.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.

Coal seams are commonly associated with poor quality water that requires treatment. Water treatment can be very expensive and can severely affect the profitability of mining projects. This study investigated the potential cultivation of Arthrospira maxima (Spirulina) in coal seam water to beneficiate coal seam water in order to effectively offset the water treatment cost. The study was conducted in Northern South Africa and formed part of a larger Coal Seam Water Beneficiation Project (CSWBP). The study consisted of laboratory based Flask Studies and outdoor High Rate Algal Pond Studies. The Flask Studies that were carried out in the on-site field laboratory, found that the coal seam water could provide a suitable medium for Spirulina cultivation. In addition, it was found that the optimal pH for the selected strain ranged between 9 - 10.5 and that the addition of excess iron, up to 100 times the concentration found in defined growth media such as Schlösser’s, to the culture media could enhance productivity. The High Rate Algal Pond Studies (HRAP) were carried out over a period of 18 months. The studies showed that the coal seam water at the CSWBP is a valuable resource that can reduce media costs by 50% without affecting productivity. In a study encompassing 334 days it was shown that heating the culture through plate heat exchangers would result in a significant increase in productivity and a heated productivity of 19.86 g/m2/day was recorded. An unheated productivity of 14.11 g/m2/day was recorded. Therefore, it was found that it would be economically feasible to beneficiate coal seam water found at the CSWBP through the cultivation of Arthrospira maxima (Spirulina).
Environmental Sciences
M. Sc. (Environmental Science)

D. Tech. Chemistry
The increase in industrialisation in South Africa has led to an increase in coal mining and coal utilisation in Mpumalanga. This has resulted in the deterioration in the quality of water upstream of Loskop Dam. Little or no information is available on the occurrence or fractionation of trace metals in sediments, which are reservoirs for pollutants. Furthermore, no information is available concerning the occurrence of polycyclic aromatic hydrocarbons (PAHs), known for their carcinogenic and mutagenic effects, in rivers in the area. The possible impact of leaching of elements and organic compounds from South African coals has not been exhaustively researched. The general objectives of the study were to: 1) assess the impact of potentially toxic metals and organic compounds leaching from coal, on the quality of surface waters via simulated leaching experiments; 2) determine the extent of pollution by trace metals and polycyclic aromatic hydrocarbons of the Olifants, Klein Olifants and Wilge rivers, at selected points in the upper catchment area; and 3) identify and apportion sources of polycyclic aromatic hydrocarbons in the sediment samples from the study area.

M.Sc. (Geography)
Coal mined in South Africa for the competitive international market, has to be selected to meet the many quality specifications of customers. This upgrading is done by washing the coal in a heavy medium separation plant. Marketable coal, discard and slurry are produced from this washing. Discard consists mainly of poor quality coal, carbonaceous shale and waste rock. Iron pyrite (FeS2) occurs in all of the above in higher concentrations than in the marketable coal. Both the carbonaceous materials and pyrites generate heat when oxidizing. If this oxidation is not arrested at an early stage on a discard dump and the temperature of the dump increases above BOoC, spontaneous combustion is quite likely. The South African Council for Scientific and Industrial Research (CSIR) has estimated that smouldering discard dumps in the Eastern Transvaal highveld region contribute approximately 400 000 tons of S02 per annum to the atmospheric pollution in that area. As a result, significant localized acid rain occurs, Louw (1990). The oxidation of iron pyrites to sulphuric acid, and the oxidation of other trace elements, is accelerated under the high temperature conditions generated by spontaneous combustion. Leaching of these oxidation products results in local groundwater and surface water contamination. This study describes different disposal technique and pilot study aimed at minimising the oxidation within the dumps. Slurry, which consists of discard and/or coal of less than 1 mm in diameter is co-deposited with discard in sequential layers of approximately 200 mm thick. This has resulted in reducing the permeability, porosity and air and water exchange within the dump. This in turn has led to a reduction in spontaneous combustion, pollution and costs. A visual increase in stability of the discard dumps, moisture content and operational ease of placement were experienced. The saleable value of the dump as a low value heat source is also preserved.

A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, for the Degree of Master of Science.
storage and waste dumps from coal mining tend to spontaneously combust. This is mainly as a result of the oxidation process which is accelerated by the availability of oxygen and the exothermic nature of the oxidation process. In cases of poor ventilation the heat accumulation within the bed is thought to lead to the spontaneous combustion of coal. The work in this dissertation aims to investigate the change in oxygen concentration in a bed of coal and also measure the rate of oxidation (oxygen absorption) in a closed reactor under isothermal conditions. Drying rate of coal under nitrogen was also looked into. An analysis of the oxygen concentration profile in a three metre 20 cm ID plastic column filled up with coal has been carried out. As the coal ages (becomes oxidised) its reactivity towards oxygen decreases and changes in the oxygen concentration profile are noticed. Experiments have been carried out up to 8 months and from the results obtained, a simple pseudo-steady-state model has been developed to describe the diffusion of oxygen into a reacting coal bed. The findings could prove useful in trying to find a solution to coal and waste dump fire control. The second experiment is a simple isothermal oxygen absorption experiment in which the rate of absorption of oxygen on a given coal sample is measured at different initial concentrations of oxygen. The initial concentration of oxygen is varied over a fairly wide range in order to determine the dependence of the rate of oxidation on the oxygen concentration. The rate- limiting step in low temperature oxidation of coal is found to be the absorption of oxygen. Moisture also plays a role in coal oxidation. Drying experiments were also carried out so as to quantify and investigate the rate of loss of moisture. Models have been developed which try to explain the mechanisms involved in the drying process. The modelling suggest that the bound water model is more appropriate to the type of behaviour exhibited during the drying process
Andrew Chakane 2018

A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg in partial fulfilment of the requirements for the degree of Master of Science in Engineering Johannesburg, 1993
Superfines of less than 200 micron are generated when mining coal. They have not been successfully beneficiated in the past and are not acceptable to the consumer. A processh as been developed whereby the superfines are beneficiated, briquetted without the use of binders and devolatilised to produce a premium smokeless briquette which will attract a premium price in the export market. [Abbreviated abstract. Open document to view full version]
MT2017

Research Doctorate - Doctor of Philosophy (PhD)
Billions of tons of mineral wastes are generated annually by the Australian open-cut coal-mining industry. These wastes include the waste rock which is excavated in order to access the underlying coal seams, and the impurities which are removed when processing the unrefined raw coal. These processing wastes include a gravel-dominated coarse reject stream and a slurry-like tailings reject stream. Typically, the rock waste is disposed of in massive fill structures commonly termed waste dumps or spoil piles, which may be hundreds of meters in height. Coarse rejects from coal processing are trucked to and disposed of in the spoil piles, whilst the fine tailings rejects are traditionally pumped to and disposed of as an aqueous slurry in large tailings dams. These tailings dams are a major source of safety, environmental and financial risk for mine operators and as such, are subject to increasing financial, social and legislative pressures, coinciding with a decrease in the availability of land on which they can be constructed. An emerging waste disposal strategy in the Australian coal mining industry is spoil-pile codisposal. This entails partly dewatering the tailings rejects, mixing them with the coarse rejects, then disposing of the mixed rejects (herein termed mixed plant rejects or MPR) with the waste rock in the spoil pile. Spoil-pile co-disposal eliminates the requirements to establish and operate a tailings dam and therefore eliminates the associated risks. However, the introduction of potentially low-strength MPR mixtures with relatively high moisture contents poses an increased likelihood of spoil pile slope instability. To date, implementation of spoil-pile co-disposal in the Australian coal mining industry has been largely empirical and based on a “trial and error” approach for waste dump design. Engineering based stability assessments are seldom performed as, at present, the fundamental behaviour or MPR within a spoil pile is not well understood. This is largely attributable to a limited understanding of how various hydrogeological processes facilitate excess pore pressure and varying degrees of saturation during spoil pile construction.

Industrialisation involves large scale use of natural resources- coal, iron, bauxite, etc. The current technology though highly advanced, yet have limited scope to use all the earth resources. Thus, it often produces huge amount of waste- undesirable by-products of those earth materials. Those by-products many a times adversely affect the environment as well as sustainable development. Coal mine overburden, fly ash and red mud are some of those prominent by-products. There exist many attempts to enhance the usage of those, often in developing new composite products. Although a lot of work exists on particulate filled composites, reports on the use of industrial or mining wastes as particulate fillers are rare. Only a few studies on use of wastes like red mud, fly ash, copper slag etc. in polymer composites have been reported so far. However, owing to the high cost of conventional fillers, this is emerging as a subject of extensive research in recent years. In view of this, the present work is undertaken which includes development of a new class of composites using coal mine overburden material of mining sites and some other industrial wastes like red mud and fly ash. This investigation is an attempt to develop different polymer composites using coal mine overburden material along with red mud and fly ash as potential filler ingredients. These particulate fillers in epoxy exhibit impressive compatibility among constituent materials. Incorporation of coal mine overburden material has resulted in substantial improvement in the wear resistance of epoxy resin. Dry sliding wear characteristics of these composites have been successfully analysed using Taguchi experimental design. The analysis reveals that overburden material content and the sliding velocity are the most predominant control factors affecting the wear rates of the composites. The results also show overburden material percentages have direct bearing on the compressive strength as well as the wear resistance and inverse relation with the tensile strength. The developed composite materials have potential to be used in multiple applications as sliding doors, mine headings, replacement of brattice cloth, etc.

碩士
國立中興大學
水土保持學系
93
In the initial period of Taiwan’s restoration, the coal was an important energy resource in Taiwan. There were many abandoned collieries in all parts of Taiwan. Majority of abandoned coal refuse banks had not been restored with proper treatment exploitation. The mining sites belong to acid sulfate soils zone. It is difficult to carry out revegetation. Only M.floridulus could be invade and grow at these sites. The erosion of the bared grounds was sources of all sorts of problems for landscape, environmental, ecological, soil and water conservation. This paper is to investigate the problems of soil and water conservation for the abandoned coal refuses bank at coal mine in Miaoli County. We have studied on the application of the revegetation methods to restoration in acidic coal soils.

The Fording River, Greenhills and Line Creek Operations are three surface coal mines located adjacent to each other in the Fording and Elk River valleys of southeastern British Columbia. These mines are operated by Elk Valley Coal Corporation, and produce high-quality metallurgical coal. Active programs of reclamation research have been conducted on all three properties. One of the primary objectives of this research has been to evaluate the feasibility of reclamation directly on coal waste, as opposed to reclamation utilizing an overlying capping material. This paper reports on the results, both historic and recent, of this research, and presents conclusions on the success of this practice, as well as future directions for confirming this success.