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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.
41

A question of control : social and industrial relations in the South Wales coalfield and the crisis of post-war reconstruction, 1914-1921

May, Edward January 1995 (has links)
No description available.
42

Applied rock cutting : a study of partial face disc cutting with blunt disc cutters /

Schmidt, Stuart. January 2005 (has links) (PDF)
Thesis (Ph.D.) - University of Queensland, 2005. / Includes bibliography.
43

Characterization of noise and design of active noise control technology in longwall mines

Rai, Arunkumar R. January 2005 (has links)
Thesis (M.S.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains xi, 65 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 63-64).
44

Performance study of mechanical loading machines in coal mining practice

Uyetake, Kor, January 1947 (has links) (PDF)
Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1947. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed July 9, 2010) Includes bibliographical references (p. 48).
45

EVALUATION OF THE PERFORMANCE OF FLOCCULATION TO ENHANCE SEDIMENT TRAP EFFICIENCY

Scott, Derek 01 January 2015 (has links)
Weathered sandstone materials have seen increased use in reclamation due to the wide-spread adoption of the Forest Reclamation Approach (FRA) in Appalachia. Runoff from these newly FRA reclaimed sites has the potential to adversely impact aquatic environments without fine sediment retention. To reduce the size and capital investment of settling ponds, flocculant utilization was investigated. Preliminary jar tests were conducted using composite weathered mine spoil samples acquired from a surface coal mine in eastern Kentucky. Four flocculants from the Magnafloc family of products were investigated during the initial screening-level testing. Experiments were conducted at three initial sediment concentrations (500 mg/L, 2,500 mg/L and 5,000 mg/L). A nonionic flocculant, Magnafloc 351, performed best, reducing total suspended sediment to below 50 mg/L. Large scale experiments confirmed that Magnafloc 351 was effective in reducing sediment concentrations. Jar tests were expanded to determine age and environmental effects on a Magnafloc 351 solution. Magnafloc 351 performance was slightly reduced after storage in a controlled building environment for 30 days and significantly decreased after 120 days. Magnafloc 351 solution exposed to UV and high heat (111°F) was ineffective after 30 days, while storage at 4°F and 36°F for 30 days did not adversely influence performance.
46

Contents and forms of potentially toxic elements in reclaimed dumpsite soils after brown coal mining in Northern Bohemia

Vasilkova, Anna January 2015 (has links)
It is an ordinary practice to cover the areas after brown-coal mining with natural topsoil cover (topsoiling). Topsoiling is removal one topsoil from agricultural land, forest or area with vegetation and excavating to another place with poor organic matter content or in our case the brown-coal mining dumpsite. Advantages of topsoiling include higher organic matter and greater available water-holding capacity and nutrient content. Content of potentially toxic elements is very low. Ammonia nitrate (NH4NO3) extraction, BCR sequential analysis and aqua regia determination were applied in this study to prove that the proportion of bioavailable forms of PTE in reclaimed soils is also low. Amounts of potentially toxic elements were compared between different types of reclamation: an agricultural shown higher value for Pb and Cd, forestry has only one contaminant -- Cd. The research shows that toxicity of soil is low and has no dangerous influence for agricultural application.
47

Added value of using real-time resource reconciliation in coal mining

Yüksel, Cansin, Benndorf, Jörg 28 September 2017 (has links) (PDF)
Recently, an efficient resource model updating framework was proposed with the aim of improving the raw material quality control and process efficiency in any type of mining operation. This includes the integration of online-sensor measurements that are obtained during the production into the resource model. The concept has been applied in a coal mining environment with the aim of identifying local impurities in a coal seam and to improve the prediction of coal quality attributes in neighbouring blocks. The goal of this presentation is to demonstrate how the use of the resource model updating framework can provide added value for the mining industry. Both economical and environmental considerations are taken into account when the added value is investigated.
48

Natural resources control trajectory : customary rights, coercive conservation and coal mining in the Yayo District, Southwest Ethiopia

Suleman, Kassahun Kelifa January 2016 (has links)
Philosophiae Doctor - PhD / The Yayo district in southwest Ethiopia is a biodiversity hotspot area historically containing a rich diversity of wild coffea arabica cultivars and Afromontane forest species of commercial and scientific value. Informed by political ecology and using qualitative research methods, notably participant observation, personal interviews, transect walks and analysis of secondary literature and videos, the study documents three major shifts in access, use, control and management of wild coffee and other natural resources in the Yayo district: first, village-level small-scale wild coffee cultivation and forest product harvesting; second, conservation and designation of protected forest areas and use zones, and most recently, coal mining and the future development of a fertiliser plant. The study details in depth how these three resource control regimes came to be and especially the social impacts they entailed on local (indigenous) communities residing in four villages in the Yayo district: Achebo, Gechi, Wabo and Wutete. It concludes with a discussion on the local socio-ecological impact and challenges facing the long-term survival of the local communities and wild coffea arabica forest biodiversity in the area. Since the early 1900s, the wild coffee forests were managed and used by local, indigenous communities based on customary social institutions including Abbaa lafaa, Ciiqaashuum, Qoroo, Tullaa, Xuxxee, and Shaanee. These institutions eroded overtime as the Ethiopian state working in tandem with professional conservationists valued the wild coffee forests for their forest biodiversity and strove to control historic wild coffee use through protectionist approaches. The thesis discusses how the restriction of access not only resulted in a range of negative social effects (such as displacement, joblessness, and landlessness) but also gave rise to occasional local conflicts and formal and informal resistance towards the conservationists and their programmes. As such, the protectionist approach did not succeed in safeguarding the wild coffees or the livelihoods of the local communities. Threats to the wild coffee forests were subsequently raised again with the rise of largescale coal mining operations in the forest. Driven by concern for economic growth, the state has shifted its attention from biodiversity preservation to supporting a coal mining operation in the area and the construction of the first-ever in country fertiliser factory in Yayo. With the advent of coal mining interests, not only have the historic customary rights and livelihoods of local communities been further weakened but also those of the power of the conservation regime. The early construction phases of the fertiliser factory have led to involuntary displacements, unfair expropriation of villagers’ properties, forest and wild coffee clearance, emergence of new diseases such as malaria, and damage to physical infrastructure. Overall, the study shows that the progressive shifts in resource access, control and use have occurred as a result of changing ecologies, ecological knowledge and values, community dynamics, economies, and the shifting policies and strategies of the government of Ethiopia. These changes, especially the control of resources by mining proponents, suggest major challenges for the future existence of wild coffea arabica cultivars in the area and the wellbeing of local communities who had used and managed them in the past.
49

Sustainable plant production on degraded soil / substrates amended with South African class F fly ash and organic materials

Truter, Wayne Frederick 28 January 2008 (has links)
South Africa is a country with very little prime farmland. A large percentage of this high agricultural capability land is generally acidic and nutrient poor, and situated in areas where large coal mining activities occur. Coal mining and agriculture are important industries in South Africa. They impact extensive land areas, and often compete for the same land. The surface mining of coal seriously damages the surface soil, local flora and fauna. Mining wastes viz. overburden, discards and mine effluents, have also created land degradation problems. Three of the most common factors that characterize degraded substrates are soil acidification, nutrient depletion and loss of biological activity. To ensure a healthy and productive vegetation, disturbed soils need to be ameliorated effectively. Using conventional methods is costly and is often not sustainable. The challenge is, therefore, to use potential alternative ameliorants in an economically, ecologically and socially sustainable manner. Fortunately, South Africa has plenty of industrial and organic by-products, which might be used as alternative ameliorants. There is an enormous amount of international literature on the use of class C fly ash, (Sub bitumious or lignite CCB – [Coal combustion byproduct]), and to a lesser extent class F fly ash (Bitumious CCB), as opposed to South African class F fly ash, which is predominantly produced in this country. Fly ash, either by itself, or together with other wastes such as biosolids, can serve as a soil ameliorant by providing a good source of micro-, macronutrients and organic material for the reclamation of land. Previous research has shown that when sewage sludge is mixed with class F fly ash and a suitable source of reactive lime in a specific ratio, sewage sludge pasteurization will occur. The SLudgeASH (SLASH) mixture has been extensively evaluated as a soil ameliorant and has proven to be viable for the reclamation of poor and marginal soils. This study, has focused on the effect of soil ameliorants on the chemical-, physical- and microbiological properties of degraded agricultural land, mine land and other mining wastes (tailings and discards) requiring rehabilitation. This study also evaluated the affects of class F fly ash and SLASH amelioration of soils and substrates on plant production and revegetation, in comparison with conventional liming and fertilization methods currently in use. Species such as maize (Zea mays) and wheat (Triticum aestivum); pasture legumes such as lucerne or alfalfa (Medicago sativa); sub tropical grasses such as Foxtail Buffalo grass (Cenchrus ciliaris), Rhodegrass (Chloris gayana) and Smutsfinger grass (Digitaria erianthra) have been evaluated. The success of enhanced plant production, re- vegetation and sustainability of once degraded soils / substrates is an indication of the amelioration success achieved. Seed germination, root development, plant yield, plant density, botanical diversity and biological activity are parameters which can all be used to support the conclusion that alternative substrate amendment practices can improve the plant growth medium. Based on the results obtained in this study, it was concluded that fly ash and fly ash/organic material mixtures (SLASH) improved soil chemical properties such as pH, ammonium acetate extractable K, Ca, Mg and Bray 1 extractable P levels. All parameters measured were significantly influenced by the fly ash and SLASH. For example, the pH of soils impacted by acid mine drainage was improved by 240% by the use of SLASH. Other results illustrate improvements in soil physical properties such as texture, bulk density, water infiltration rate and hydraulic conductivity, by class F fly ash based soil ameliorants. In addition to the beneficial effects on soil physical properties, the microbial properties were also improved, as indicated by the beneficiation of symbiotic relationship of the Rhizobium bacteria and the important host plant Medicago sativa. Improvements in crop yields, such as: wheat yields on SLASH and fly ash treatments were 270% and 150% better than the control respectively; yields of maize and alfalfa were improved by 130 % and 450% respectively, were also registered. Fly ash and SLASH ameliorated soils resulted in approximately 850%, 266% and 110% higher dry matter production on gold mine tailings, AMD impacted soil and acidic mine cover soil, respectively, relative to the control treatments. Results also clearly illustrated that the abundance of certain species can be related to the higher fertility levels of the rehabilitated soil. Data collected over the past seven years, illustrates how the botanical composition has changed, and that soils receiving class F fly ash and sewage sludge had a higher dry matter production, whereas the control (no treatment) had a better biodiversity. With respect to the reclamation of coal discard materials, significant increases in yield, of up to 200%, were noted for soils and discards treated with class F fly ash, relative to the untreated control. The pH of cover soil was the most strongly affected soil parameter during the experimental period. Class F fly ash and SLASH have the potential to improve the chemical, physical and microbiological properties of degraded soils and substrates. From this experimental work it can be concluded that class F fly ash from Lethabo definitely has a much higher CaCO3 equivalent than what was originally assumed and that other SA sources probably have an even better neutralizing value. Class F fly ash and SLASH, are good sources of micronutrients and some macro nutrients, and may play a significant role in neutralizing acidity due to their residual alkalinity, and thus ability to continuously change the soil chemical balance so that nutrients become more available for plant uptake and use, thereby enhancing growth. Agricultural, domestic and industrial byproducts unfortunately, vary greatly in nutrient content, trace metals and liming potential, and these factors can affect both re-vegetation success and the environmental impact of reclamation. Co-utilization of by-products can often combine beneficial properties of the individual by-products to eventually have a more pronounced effect on the degraded soil or substrate. / Thesis (PhD(Pasture Science))--University of Pretoria, 2008. / Plant Production and Soil Science / PhD / unrestricted
50

The role of legislation and management practices in the coal mining industry on the Olifants River catchment, South Africa

Zermatten, Carrie 20 November 2012 (has links)
The economic development of South Africa has relied heavily on coal mining and water quality is adversely affected by mining - thus coal mining poses a significant risk to South Africa’s water resources. Ensuring judicious use and management of natural capital is always a complex undertaking but the benefits to the mining industry and society as a whole, derived from thoroughly laid-out plans, a supportive but strict regulatory environment and decision-making processes based on sound, scientific information are immense. Value addition to mining products is important to promote conservation of assets and resources. Using the Olifants Water Management Area as a case study, the chemistry of groundwater associated with coal mining was characterised. General concepts regarding the relationship of geology to water chemistry are surmised. Copyright / Dissertation (MSc)--University of Pretoria, 2012. / Geology / unrestricted

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