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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Sukcese vegetace a vývoj půd na výsypkách po těžbě hnědého uhlí / Vegetation succession and soil development on heaps from brown coal mining

Veselý, Martin January 2012 (has links)
Plant diversity and selected soil parameters from 36 sites placed on brown coal mining spoil heaps were analyzed and compared. Spontaneously revegetated or technically reclaimed spoil heaps of different age were situated in brown coal mining district of eastern Most basin in north western part of the Czech republic. Samples were sorted in groups according to vegetation growth and type. Plant diversity increases during succession development and is higher on non-reclaimed sites than reclaimed sites, where diversity decreases with time. Soil bulk density decreases during succession on all sites. Soil pH is decreasing too and this process is faster on spontaneously revegetated sites. Old successional forest type sites have very acid soils probably due to properties of original mineral matrix. Thickness of organic horizon and A horizon is increasing during succession and they appear in mid-aged sites first. Content of soil organic carbon is increasing continuously. Non-reclaimed sites reach higher contents, mainly because of higher content of fossil organic matter in spoil mineral matrix. Keywords: vegetation succession, soil development, reclamation, brown coal mining heaps
72

Vliv toxicity a ostatních vlastností výsypkových substrátů na růst rostlin / The effect of toxicity and othet parameters of substrate on plant growth in post mining sites.

Zadinová, Radka January 2013 (has links)
Surface mining of coal in the country leaves a lot of damage. This type of mining is characterized by the creation of large external dumps. The dumps often contain substrates with toxic substances or substances which become toxic after reaction with air. These substrates are toxic to plants and edaphon. This work is intended to show what properties of substrates are important for phytotoxicity. The location of research was selected including 3 different kinds of substrates, terrain unevenness and a lagoon in the middle. Coordinate grid has been created on the selected location. At each point a test was conducted with plant Sinapis alba and biomass was extracted from a naturally growing vegetation. Further, at the points substrates were collected and values of pH, conductivity and arsenic were measured. Test with plant Sinapis alba was repeated in the laboratory conditions as well. On site GPS coordinates were measured for the mathematical model created in ArcGIS. Experiment has shown the importance of the type of substrate and the geologic description, and then the association between dejection, value of pH and conductivity. Conductivity and pH levels also correlate with the germination Sinapis alba and biomass of naturally growing vegetation.
73

Impacts of Mountaintop Removal Coal Mining on the Mud River, West Virginia: Selenium Accumulation, Trophic Transfer, and Toxicity in Fish

Arnold, Mariah Christine January 2014 (has links)
<p>Selenium (Se) is a micronutrient necessary for the function of a variety of important enzymes; Se also exhibits a narrow range in concentrations between essentiality and toxicity. Oviparous vertebrates such as birds and fish are especially sensitive to Se toxicity, which causes reproductive impairment and defects in embryo development. Selenium occurs naturally in the Earth's crust, but it can be mobilized by a variety of anthropogenic activities, including agricultural practices, coal burning, and mining. </p><p>Mountaintop removal/valley fill (MTR/VF) coal mining is a form of surface mining found throughout central Appalachia in the United States that involves blasting off the tops of mountains to access underlying coal seams. Spoil rock from the mountain is placed into adjacent valleys, forming valley fills, which bury stream headwaters and negatively impact surface water quality. This research focused on the biological impacts of Se leached from MTR/VF coal mining operations located around the Mud River, West Virginia. </p><p>In order to assess the status of Se in a lotic (flowing) system such as the Mud River, surface water, insects, and fish samples including creek chub (Semotilus atromaculatus) and green sunfish (Lepomis cyanellus) were collected from a mining impacted site as well as from a reference site not impacted by mining. Analysis of samples from the mined site showed increased conductivity and Se in the surface waters compared to the reference site in addition to increased concentrations of Se in insects and fish. Histological analysis of mined site fish gills showed a lack of normal parasites, suggesting parasite populations may be disrupted due to poor water quality. X-ray absorption near edge spectroscopy techniques were used to determine the speciation of Se in insect and creek chub samples. Insects contained approximately 40-50% inorganic Se (selenate and selenite) and 50-60% organic Se (Se-methionine and Se-cystine) while fish tissues contained lower proportions of inorganic Se than insects, instead having higher proportions of organic Se in the forms of methyl-Se-cysteine, Se-cystine, and Se-methionine. </p><p>Otoliths, calcified inner ear structures, were also collected from Mud River creek chubs and green sunfish and analyzed for Se content using laser ablation inductively couple mass spectrometry (LA-ICP-MS). Significant differences were found between the two species of fish, based on the concentrations of otolith Se. Green sunfish otoliths from all sites contained background or low concentrations of otolith Se (< 1 µg/g) that were not significantly different between mined and unmined sites. In contrast creek chub otoliths from the historically mined site contained much higher (&#8805; 5 µg/g, up to approximately 68 µg/g) concentrations of Se than for the same species in the unmined site or for the green sunfish. Otolith Se concentrations were related to muscle Se concentrations for creek chubs (R2 = 0.54, p = 0.0002 for the last 20% of the otolith Se versus muscle Se) while no relationship was observed for green sunfish. </p><p>Additional experiments using biofilms grown in the Mud River showed increased Se in mined site biofilms compared to the reference site. When we fed fathead minnows (Pimephales promelas) on these biofilms in the laboratory they accumulated higher concentrations of Se in liver and ovary tissues compared to fathead minnows fed on reference site biofilms. No differences in Se accumulation were found in muscle from either treatment group. Biofilms were also centrifuged and separated into filamentous green algae and the remaining diatom fraction. The majority of Se was found in the diatom fraction with only about 1/3rd of total biofilm Se concentration present in the filamentous green algae fraction </p><p>Finally, zebrafish (Danio rerio) embryos were exposed to aqueous Se in the form of selenate, selenite, and L-selenomethionine in an attempt to determine if oxidative stress plays a role in selenium embryo toxicity. Selenate and selenite exposure did not induce embryo deformities (lordosis and craniofacial malformation). L-selenomethionine, however, induced significantly higher deformity rates at 100 µg/L compared to controls. Antioxidant rescue of L-selenomethionime induced deformities was attempted in embryos using N-acetylcysteine (NAC). Pretreatment with NAC significantly reduced deformities in the zebrafish embryos secondarily treated with L-selenomethionine, suggesting that oxidative stress may play a role in Se toxicity. Selenite exposure also induced a 6.6-fold increase in glutathione-S-transferase pi class 2 gene expression, which is involved in xenobiotic transformation. No changes in gene expression were observed for selenate or L-selenomethionine-exposed embryos.</p><p>The findings in this dissertation contribute to the understanding of how Se bioaccumulates in a lotic system and is transferred through a simulated foodweb in addition to further exploring oxidative stress as a potential mechanism for Se-induced embryo toxicity. Future studies should continue to pursue the role of oxidative stress and other mechanisms in Se toxicity and the biotransformation of Se in aquatic ecosystems.</p> / Dissertation
74

Decentralized bargaining in the bituminous coal industry ? : emerging shifts in power relations

Cummings, Katina January 1981 (has links)
Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH. / Includes bibliographical references. / by Katina Cummings. / M.C.P.
75

Mineração de carvão na bacia carbonífera de Moatize, província de Tete - Noroeste de Moçambique: uma análise socioambiental / not available

Macie, Aniceto Elcidio Alves 03 September 2015 (has links)
Este pesquisa teve como objetivo avaliar os principais impactos socioambientais decorrentes da mineração de carvão na Bacia Carbonífera de Moatize, em relação à qualidade dos corpos hídricos superficiais e os conflitos gerados pelos reassentamentos das comunidades que ocupavam a área de infuência direta da mineração. A área de estudo, está inserida na Bacia carbonífera de Moatize, província de Tete, noroeste de Moçambique. Para a execução da pesquisa, fez - se a revisão bibliográfica, análise das águas superficiais nos rios Revúbuè, Moatize, Zambeze e seus tributários, e diagnóstico socioambiental das comunidades locais reassentadas (Cateme e 25 de setembro) e as da área de infuência direta da mineração (comunidade de Capanga). Foram amostrados 13 pontos de água superficial, entre os rios Zambeze, Revúboè e Moatize. Os parâmetros físico-quimicos: pH, Eh, T, CE, OD foram analisados in situ através do Multiparâmetro portátil Modelo - HI 9828 HANNA. No laboratório, foram analisados a turbidez, STD, sulfatos, Al, As, Fe, Mg, Mn e Zn determinados através do Espectrômetro de Emissão Atômica com Plasma Indutivamente Acoplado (ICP/AES). Os resultados indicam que as comunidades locais apresentam um baixo nível de safisfação com a implantação da mina, devido ao não cumprimento de algumas compensações sociais, especialmente as indenizações que desencadeiam conflitos com a mineradora. Além dos já mencionados, outros impactos ambientais decorrentes da mineração de carvão são: alteração da qualidade das águas superficiais, vibrações de terreno e ruídos que representam desconforto para as comunidades locais. Os conflitos sociais constatados são: alteração de valores e hábitos tradicionais, essenciais para a solidariedade, unidade das famílias; privação das mulheres dos seus meios de ocupação tradicionais (agricultura), tornando-as dependentes; não cumprimento das compensações sociais; campos agrícolas de baixa fertilidade em relação às que possuíam antes; as áreas de pastagem estão distantes das residênciais; as habitações apresentam fendas no piso e infiltração da água quando chove; e a falta de meios de sobrevivência, sendo que as comunidades locais vivem na base de agricultura e pecuária. Através das amostras e análises físico-quimicas das águas superficiais, constatou-se que alguns pontos apresentam alterações e valores estão fora dos limites mínimos e máximos estabelecidos no Diploma Ministerial n o 180/2004 e Resolução CONAMA nº 357/05, nomeadamente: o pH no P10 (9,99); o OD no P5 (4,85 mg/L); os STD no P9 (2010 mg/L), P8 (1810 mg/L) e P7 (1052 mg/L); os sulfatos no P8 (680 mg/L) e P9 (710 mg/L), o Fe no P3 (0,98 mg/L), P4 (0,4 mg/L), P5 (0,9 mg/L), P10 (1,03 mg/L), P12 (1,8 mg/L) e P13 (1 mg/L) no rio Moatize; o Mg no P7 (78,8 mg/L), P8 (126 mg/L), P9 (136 mg/L) e P12 (313 mg/L). Essa alteração provavelmente é influenciada pela agricultura familiar, partículas sólidas em suspensões oriundas das minas de carvão, que possam percolar até atingir os corpos hídricos. Os pontos P7, P8 e P9 no rio Revúboè nas proximidades de Minas Moatize Ltda, da pedreira da empresa Vale e Ceta são assinalados como áreas críticas que carecem de monitoramento ambiental. / This research aimed to evaluate the main environmental impacts of coal mining in the Moatize coal basin related to the quality of surface water bodies and conflicts generated by resettlement of the communities occupying the area of direct influence of mining. The study area is inserted in the Moatize coal basin in Tete province, north-western Mozambique. The following works were carried out: literature review, analysis of surface water in Revúbuè, Moatize, Zambezi rivers and its tributaries, and environmental diagnosis of resettled local communities (Cateme and September 25) and the AID Mining (Capanga community). They were in total 13 sampling sites of surface water, between the Zambezi, Revúboè and Moatize rivers. The physical and chemical parameters: pH, Eh, T, CE, OD were analyzed in situ by portable multiparameter model HI 9828 HANNA. In the laboratory, were analyzed the turbidity, STD, Sulfides and elements such as Al, As, Fe, Mg, Mn and Zn determined by Atomic Emission Spectrometer with Inductively Coupled Plasma (ICP/AES). The results indicate that local communities have a low level of safisfation with the implementation of the mine due to non -compliance with certain social compensation, especially compensation that trigger conflicts with the mining company. The main environmental impacts of coal mining are changing the quality of surface water, ground vibration and noise that pose a discomfort for local communities. The observed social conflicts are: destruction of traditional values and habits that are essential for sustaining solidarity and unity of families and communities; deprivation of women from their traditional occupation means (agriculture), becoming increasingly dependent; non-compliance of promises; agricultural fields of low fertility than those who had before; grazing areas are more distant from residential areas; homes with low quality, with cracks in the floor and water infiltration when it rains; and the lack of livelihoods, given that local communities resettled live on agriculture and cattle breeding base, being difficult the practice currently, because of the soil quality and pasture areas. Through the samples and physical-chemical analysis of surface water, it was found that some points have changes and values are outside the minimum and maximum limits set out in the Ministerial Decree 180/2004 and CONAMA Resolution n o 357/05, namely: the pH in P10 (9.99); OD at P5 (4.85 mg / L); STDs in P9 (2010 mg / L), P8 (1810 mg / L) and P7 (1052 mg / L); sulphates in P8 (680mg / L) and P9 (710 mg / l) in the Fe P3 (0.98 mg / L) P4 (0.4 mg / L) P5 (0.9 mg / L ), P10 (1.03 mg / L), P12 (1.8mg / L) and P13 (1 mg / L) in Moatize river; Mg in P7 (78.8 mg / L), P8 (126 mg / L), P9 (136mg / L) and P12 (313 mg / L). This change is likely to be influenced by family agriculture, solid particles in suspensions derived from the coal mines, which percolaam until the water bodies. The points P7, P8 and P9 on the Revúboè river near Moatize Mines Ltd., quarry Vale and Ceta Company are marked as critical areas in need of environmental monitoring.
76

Mineração de carvão na bacia carbonífera de Moatize, província de Tete - Noroeste de Moçambique: uma análise socioambiental / not available

Aniceto Elcidio Alves Macie 03 September 2015 (has links)
Este pesquisa teve como objetivo avaliar os principais impactos socioambientais decorrentes da mineração de carvão na Bacia Carbonífera de Moatize, em relação à qualidade dos corpos hídricos superficiais e os conflitos gerados pelos reassentamentos das comunidades que ocupavam a área de infuência direta da mineração. A área de estudo, está inserida na Bacia carbonífera de Moatize, província de Tete, noroeste de Moçambique. Para a execução da pesquisa, fez - se a revisão bibliográfica, análise das águas superficiais nos rios Revúbuè, Moatize, Zambeze e seus tributários, e diagnóstico socioambiental das comunidades locais reassentadas (Cateme e 25 de setembro) e as da área de infuência direta da mineração (comunidade de Capanga). Foram amostrados 13 pontos de água superficial, entre os rios Zambeze, Revúboè e Moatize. Os parâmetros físico-quimicos: pH, Eh, T, CE, OD foram analisados in situ através do Multiparâmetro portátil Modelo - HI 9828 HANNA. No laboratório, foram analisados a turbidez, STD, sulfatos, Al, As, Fe, Mg, Mn e Zn determinados através do Espectrômetro de Emissão Atômica com Plasma Indutivamente Acoplado (ICP/AES). Os resultados indicam que as comunidades locais apresentam um baixo nível de safisfação com a implantação da mina, devido ao não cumprimento de algumas compensações sociais, especialmente as indenizações que desencadeiam conflitos com a mineradora. Além dos já mencionados, outros impactos ambientais decorrentes da mineração de carvão são: alteração da qualidade das águas superficiais, vibrações de terreno e ruídos que representam desconforto para as comunidades locais. Os conflitos sociais constatados são: alteração de valores e hábitos tradicionais, essenciais para a solidariedade, unidade das famílias; privação das mulheres dos seus meios de ocupação tradicionais (agricultura), tornando-as dependentes; não cumprimento das compensações sociais; campos agrícolas de baixa fertilidade em relação às que possuíam antes; as áreas de pastagem estão distantes das residênciais; as habitações apresentam fendas no piso e infiltração da água quando chove; e a falta de meios de sobrevivência, sendo que as comunidades locais vivem na base de agricultura e pecuária. Através das amostras e análises físico-quimicas das águas superficiais, constatou-se que alguns pontos apresentam alterações e valores estão fora dos limites mínimos e máximos estabelecidos no Diploma Ministerial n o 180/2004 e Resolução CONAMA nº 357/05, nomeadamente: o pH no P10 (9,99); o OD no P5 (4,85 mg/L); os STD no P9 (2010 mg/L), P8 (1810 mg/L) e P7 (1052 mg/L); os sulfatos no P8 (680 mg/L) e P9 (710 mg/L), o Fe no P3 (0,98 mg/L), P4 (0,4 mg/L), P5 (0,9 mg/L), P10 (1,03 mg/L), P12 (1,8 mg/L) e P13 (1 mg/L) no rio Moatize; o Mg no P7 (78,8 mg/L), P8 (126 mg/L), P9 (136 mg/L) e P12 (313 mg/L). Essa alteração provavelmente é influenciada pela agricultura familiar, partículas sólidas em suspensões oriundas das minas de carvão, que possam percolar até atingir os corpos hídricos. Os pontos P7, P8 e P9 no rio Revúboè nas proximidades de Minas Moatize Ltda, da pedreira da empresa Vale e Ceta são assinalados como áreas críticas que carecem de monitoramento ambiental. / This research aimed to evaluate the main environmental impacts of coal mining in the Moatize coal basin related to the quality of surface water bodies and conflicts generated by resettlement of the communities occupying the area of direct influence of mining. The study area is inserted in the Moatize coal basin in Tete province, north-western Mozambique. The following works were carried out: literature review, analysis of surface water in Revúbuè, Moatize, Zambezi rivers and its tributaries, and environmental diagnosis of resettled local communities (Cateme and September 25) and the AID Mining (Capanga community). They were in total 13 sampling sites of surface water, between the Zambezi, Revúboè and Moatize rivers. The physical and chemical parameters: pH, Eh, T, CE, OD were analyzed in situ by portable multiparameter model HI 9828 HANNA. In the laboratory, were analyzed the turbidity, STD, Sulfides and elements such as Al, As, Fe, Mg, Mn and Zn determined by Atomic Emission Spectrometer with Inductively Coupled Plasma (ICP/AES). The results indicate that local communities have a low level of safisfation with the implementation of the mine due to non -compliance with certain social compensation, especially compensation that trigger conflicts with the mining company. The main environmental impacts of coal mining are changing the quality of surface water, ground vibration and noise that pose a discomfort for local communities. The observed social conflicts are: destruction of traditional values and habits that are essential for sustaining solidarity and unity of families and communities; deprivation of women from their traditional occupation means (agriculture), becoming increasingly dependent; non-compliance of promises; agricultural fields of low fertility than those who had before; grazing areas are more distant from residential areas; homes with low quality, with cracks in the floor and water infiltration when it rains; and the lack of livelihoods, given that local communities resettled live on agriculture and cattle breeding base, being difficult the practice currently, because of the soil quality and pasture areas. Through the samples and physical-chemical analysis of surface water, it was found that some points have changes and values are outside the minimum and maximum limits set out in the Ministerial Decree 180/2004 and CONAMA Resolution n o 357/05, namely: the pH in P10 (9.99); OD at P5 (4.85 mg / L); STDs in P9 (2010 mg / L), P8 (1810 mg / L) and P7 (1052 mg / L); sulphates in P8 (680mg / L) and P9 (710 mg / l) in the Fe P3 (0.98 mg / L) P4 (0.4 mg / L) P5 (0.9 mg / L ), P10 (1.03 mg / L), P12 (1.8mg / L) and P13 (1 mg / L) in Moatize river; Mg in P7 (78.8 mg / L), P8 (126 mg / L), P9 (136mg / L) and P12 (313 mg / L). This change is likely to be influenced by family agriculture, solid particles in suspensions derived from the coal mines, which percolaam until the water bodies. The points P7, P8 and P9 on the Revúboè river near Moatize Mines Ltd., quarry Vale and Ceta Company are marked as critical areas in need of environmental monitoring.
77

Estudo de liberação do carvão de Candiota-RS, visando seu beneficiamento

José, David Selemane January 2011 (has links)
O presente estudo tem como objetivo à caracterização do carvão de Candiota visando seu beneficiamento. A caracterização do carvão para o seu beneficiamento tem sido de grande importância hoje, uma vez que este recurso mineral representa uma alternativa energética em todo o mundo. Entretanto, a previsão de um bom aproveitamento deste recurso mineral, não passa da necessidade da sua caracterização efetiva. O beneficiamento do carvão tem por objetivo promover a redução do teor de cinza, o aumento do teor da matéria carbonosa e conseqüentemente, do poder calorífico. Além disso, promove a redução do teor de enxofre e a obtenção de granulometrias adequadas às especificações industriais, visando a sua utilização em função das necessidades do mercado consumidor. Para a caracterização do carvão de Candiota para este estudo foram elaboradas tabelas comparativas de todas as camadas divididas em dois grupos: camadas inferiores e superiores nos furos 364, 365, 366, 368, 369, 670, 371 e 372. Devido às exigências mínimas no conteúdo de teor de cinzas no carvão mineral para o seu uso no mercado consumidor, foram pré-definidos três cortes de cinzas em 35, 42 e 48 %. Para alcançar o objetivo proposto, foi calculado para todas as camadas presentes nos furos anteriormente referidos, o concentrado e o respectivo rejeito. Também foi calculada para cada camada a recuperação mássica teórica, média ponderada nas frações -25,4 +2,0 mm e -2,0 +0,1mm respectivamente. A fração fina de -0,1 mm foi considerada para descarte. Igualmente foram elaborados os fluxogramas de beneficiamento para todas as camadas do carvão nos furos anteriormente referidos, assim como as suas respectivas curvas médias de blendagem. Não foram usados métodos estatísticos para este estudo, nem a previsão de maior recuperação usando as curvas tromp ou de erro, em contra partida foram elaboradas as curvas médias nas blendagens das camadas inferiores e superiores incluindo neste último a camada Banco Louco. / This study aims to characterize the Candiota coal processing your order. The characterization of coal to its processing has been of great impotrance today, since this non-renewable mineral resource represents an alternative energy source worldwide. However, the forecast of a good use of this mineral resource is but need for effective characterization. The beneficiation of coal aims to promote the reduction of ash content, the increase in content of carbonaceuos matter and therefore, the calorific value.It also promotes the reduction of surfur content and particle size appropriate for obtaining industrial specification for their application to the needs of the consumer market. For the characterization of coal Candiota for this study were prepared comparative tables of all seams divided in two groups: lower and upper seams in the holes 364, 365, 366, 368, 369, 370, 371 and 372. Due to the specification, the minimumm content of ash content in coal for use in the market, were pre-defined three of ash 35, 42 and 48%. To achive the proposed objective, was calculated for all seams in the holes previously mentioned, its concentrate and their waste. Was also calculated for each seams theoretical mass recovery ash content, calculate the weighted average fractions -25,4 +2,0 mm and -2,0 +0,1 mm respectively. The fine fraction of -0,1 mm was considered for disposal. Also were prepared flowcharts of processing for all seams of coal holes mentioned above, as well as their respective average curves blending. No statiscal methods were used for this study, neithet the higher recovery prediction curves using tromp or error, starting from the average curves were prepared in blends of lower and upper seams including the discontinue seam.
78

"A Spark" With Critical Introduction "Ore and Lore: Mining, Literature, and Loss"

Warren, Andrea J 01 December 2015 (has links)
This thesis explores the emotional, physical, and familial repercussions of coal mining in the Appalachian region, especially in regards to relationships within the community. The thesis is divided into two parts; a critical essay in which the objective facts, statistics, and histories of coal mining are addressed, and a short story which shares the subjective experience of the Hicks family.
79

INVESTIGATION OF THE EFFECTIVENESS OF AN INTEGRATED FLOODED-BED DUST SCRUBBER ON A LONGWALL SHEARER THROUGH LABORATORY TESTING AND CFD SIMULATION

Arya, Sampurna N. 01 January 2018 (has links)
Dust generation at an underground coal mine working face continues to be a health and safety issue. Prolonged exposure to high concentrations of airborne respirable dust can cause a debilitating and often fatal respiratory disease called Black Lung. In addition, the deposition of float dust in mine return airways poses a serious safety hazard if not sufficiently diluted with inert rock dust. A localized methane explosion can transition into a self-propagating dust explosion. Since dust is a byproduct of various mining activities, such as cutting and loading, crushing, and transportation, the dust-related issues cannot be totally eliminated. However, the adverse health effects and safety concerns can be minimized if a significant amount of the generated dust is removed from the ventilation air by a mechanical device, such as a dust scrubber. Over the last three decades, flooded-bed dust scrubbers integrated into continuous miners have been successfully applied for capturing and removing airborne dust generated at the working face. According to the National Institute for Occupational Safety and Health (NIOSH), a flooded-bed scrubber can achieve more than 90% capture and cleaning efficiencies under optimum conditions. Although flooded-bed scrubbers have proven useful in the vast majority of cases, they have not yet been successfully applied to a longwall face. In the United States, numerous attempts have been made to reduce dust concentration at a longwall face through the application of a scrubber; but, none were successfully implemented. Encouraged by the successful use of a flooded-bed scrubber system at continuous miner faces, this research revisits the flooded-bed scrubber concept for a longwall shearer. For this investigation, a full-scale physical model of a Joy 7LS longwall shearer, modified with an integrated flooded-bed dust scrubber, was designed and fabricated at the University of Kentucky. The scope of work for this research was limited to capturing and cleaning dust generated near the shearer headgate drum only. The mock-up was transported to, and assembled in, the full-scale longwall dust gallery at the NIOSH Pittsburgh Research Laboratory (PRL). Tests were conducted to examine: (1) the effect of the scrubber on headgate-drum dust reduction and (2) the combined effect of the scrubber and splitter sprays on headgate drum dust reduction. Analysis of test results for the scrubber-alone condition indicates a significant dust reduction of up to 57% in the return airway and 85% in the test gallery walkway, whereas the combination of scrubber and splitter-arm sprays shows dust reduction of up to 61% and 96% in the return and walkway, respectively. These results indicate that a flooded-bed scrubber integrated into a longwall shearer can be used as a viable technique to reduce a large portion of airborne dust at a longwall face. Subsequently, a Computational Fluid Dynamics (CFD) model of the longwall gallery and shearer was developed and validated using the results of the experimental study. The CFD simulation results are in good agreement with the experimental results with a maximum of 9.7% variation. This validated CFD model can be used in future research to predict the effects of modifications to the scrubber system, including modifications to the scrubber inlet, to optimize the scrubber design, and to evaluate the effectiveness of adding a tailgate drum dust scrubber.
80

Subsidence prediction and mine design for underground coal mining in the Collie Basin.

Misich, Ian J. January 1997 (has links)
The subsidence characteristics of the Collie Basin sediments have been investigated to provide site specific design criteria for the Wongawilli method of coal extraction. As historical coal extraction (bord and pillar) methods did not generally give rise to large scale subsidence, there were very few details on mining subsidence in the Collie Basin available to base any design methodology on. Consequently, the investigation was conducted on a Green fields basis. Firstly, the mechanisms involved in the development of mining subsidence needed to be investigated and identified. It was then necessary to determine the effects that mining subsidence would have on mine and ground mass (specifically aquitards) structures and surface features. Once these two areas of work were completed, design criteria were formulated to manage the effects of mining subsidence by controlling the critical mechanisms of subsidence development.The results from this study have greatly enhanced the level of understanding of the subsidence mechanisms involved, and allowed for the development of predictive models which can be used for the design of coal extraction by the panel/pillar mining method in the Collie Basin. Mine planning engineers can now use this design information to derive the most cost effective methods for the extraction of coal within the Collie Basin.

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