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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.
1

Costs of reclaiming surface mined lands : seven county area of the Ohio coal region

Flocken, Jennifer Cotterill January 1979 (has links)
No description available.
2

Effect of Various Saturation Levels, Leaching Solution pH, and Leaching Cycle on Electrical Conductivity from Coal Mine Spoil Leachate

Parker, John Martin 04 September 2013 (has links)
Historically, environmental research associated with Appalachian coal surface mines focused on acid mine drainage and reclamation. Recent studies suggest that electrical conductivity (EC) levels above 500 ?S cm-1 can impair Appalachian streams, shifting the focus towards limiting release of total dissolved solids (TDS) and associated elements of concern. Previous column studies utilized an unsaturated bi-weekly leaching design to evaluate the behavior of overburden with respect to TDS, pH, and trace metals. The objective of this study was to determine the effects of column saturation, leaching solution chemistry, and leaching cycle on the release of TDS and associated elements from an unweathered sandstone. Treatments evaluating potential saturation, leaching solution pH, and leaching cycle included saturated, standard method, vacuum, and standpipe fitted columns; simulated acid rain, de-ionized water, and CaCO3 leaching solutions; and 2x week-1, 1x week-1, 2x month-1, and 1x day-1 leaching cycles. Saturation level in the column significantly impacted leachate pH, EC level, and the release of sulfate, bicarbonate, and associated cations by potentially affecting trace sulfide oxidation and carbonate dissolution reactions. Little evidence of saturation was noted with the standard method. Leaching solution bulk chemistry did not alter leachate chemistry. Longer times between dosing cycles corresponded to higher EC, bicarbonate, and associated cation levels, especially over time. Sulfate, Ca, and Se exhibited the greatest percent release based on total mass losses during peak elution. For managing TDS, time between precipitation events and saturation level can strongly affect short and long-term EC level, its major contributors, and elements of concern. / Master of Science
3

Razvoj modela za unapređenje proizvodnog procesa i smanjenje uticaja gubitaka neuravnoteženosti i preopterećenja - Lean 3M / Development of a model for improving the production process and reducing the impact of waste uneveness and overbuden losses - Lean 3M

Mandić Jovan 27 September 2019 (has links)
<p>Istraživanje u doktorskoj disertaciji obuhvata kreiranje modela za unapređenje proizvodnih procesa i smanjenje uticaja pojva koje se javljaju u sistemima, a to su pre svega pojave gubitaka, neuravnotežeonsti i preopterećenja. Na osnovu pregleda literature, uočeni su nedostaci postojećih modela i kreiran je novi model koji je primenjen u realnom okruženju, a potom su prikazani rezultati njegove implementacije. Takođe ukazano je na postojanje međusobno uzročno-posledičnih veza između pojava i određen je stepen njihovih uticaja. Rezultati primene ovakvog modela doprinose smanjenju pojava 3M koji se javljaju u proizvodnim procesima i kreiraju osnovu za dalji kontinualan razvoj i unapređenje proizvodnih procesa i sistema u celini.</p> / <p>Doctoral dissertation research involves the develepment of a model for improving production processes and reducing the impact of waste unevenness and overburden losses that occurs in a system. Based on the literature review, the shortcomings of the existing models were identified and a new model was created. It has been applied in the real company environment and the results of its implementation are shown. It is also pointed to the existence of caus-related relationships between muda mura and muri, showing the impact of their influences. Results contributes to the reduction of 3M losses and will create the basis for further continuous development and improvement of the production processes and the system as a whole.</p>
4

Assessment of Biogeochemical Maturation of Overburden Disturbed by Surface Mining

Poncelet, Dominique M. 15 August 2011 (has links)
No description available.
5

Effect of Leaching Scale on Prediction of Total Dissolved Solids Release from Coal Mine Spoils and Refuse

Ross, Lucas Clay 24 August 2015 (has links)
Coal surface mining in the Appalachian USA coalfields can lead to significant environmental impacts including elevated total dissolved solids (TDS) levels in receiving streams. Column leaching procedures are recommended by many studies for TDS prediction, but many question their applicability to field conditions. The objective of this study was to assess results from a simple column leaching method relative to larger scale leaching vessels (scales) using one coal mine spoil and two coarse coal refuse materials. A non-acidic mine spoil sample from SW Virginia (crushed to ≤ 1.25 cm) was placed into PVC columns (~10 cm x 40 cm) in the laboratory and leached unsaturated with simulated acidic rainfall. The same spoil was also placed into larger 'mesocosms' (~1.5 m³) with run-of-mine material and into barrels (~0.1 m³; screened to ≤ 15 cm) under natural field environmental and leaching conditions. Similarly, two coarse coal refuse samples were placed into lab columns and field barrels. Comparative results suggest the column method was a reasonable predictor of TDS release from the coal mine spoil relative to the two larger scales studied. However, there were significant differences at times during the study, including during initial peak TDS elution (1,750 µS cm⁻¹ in columns vs. 2,250 µS cm⁻¹ in mesocosms). Field leaching also produced a distinct seasonal time-lagged EC pattern that was not observed in the columns. On the other hand, significantly different and dissimilar leaching results were noted for the refuse column vs. barrel leachates, calling into question their prediction ability for refuse. / Master of Science
6

Numerical study on ground reaction curves for shallow overburden tunnels / 小土被りトンネルでの地山特性曲線に関する数値解析的研究 / # ja-Kana

Muhammad, Shehzad Khalid 25 September 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21359号 / 工博第4518号 / 新制||工||1703(附属図書館) / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 岸田 潔, 教授 三村 衛, 教授 木村 亮 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
7

Exploring the Geomechanics of Sinkholes: A Preliminary Numerical Study

Rawal, Kishor January 2016 (has links)
No description available.
8

Analysis and modeling of high-resolution multicomponent seismic refelction data

Guy, Erich D. January 2003 (has links)
No description available.
9

Hydrostratigraphy of the Paris Moraine in the Guelph Area, Ontario, Canada

Trapp, Andrew 11 1900 (has links)
Many growing southern Ontario communities, including Guelph, rely on fractured bedrock aquifers for drinking water. Contamination and overexploitation pose a threat to these water resources, necessitating characterization of vulnerability, risks, and recharge areas. Quaternary sediments southeast of the City of Guelph, including the Paris Moraine, were investigated in order to delineate hydrostratigraphy. This was achieved through study of 9 cored-holes, as well as existing MOE, GRCA, and University of Guelph data. Falling head permeameter measurements and empirical grain-size distribution measurements and analysis were employed for determination of 𝐾𝑠𝑎𝑡 values, which were used to construct a hydrostratigraphy. Of 19 methods evaluated, The Kozeny-Carman empirical grain-size method for determining 𝐾𝑠𝑎𝑡 was found to be more representative of measured values for the study area. The area is dominated by a conductivity regime of 2.72x10-7 – 1.40x10-6 m/s with local heterogeneity present on the scale of 10’s to 100’s of meters. The Paris Moraine, particularly its backslope, is at higher risk due to its relatively high conductivity, greater occurrence of aquifer units, as well as prevalence of small-scale topographic (hummocky topography), and bedrock topographic lows. / Thesis / Master of Science (MSc)
10

Revegetation of coal mine dumps to ameliorate effects of acidic seepage.

Mikli, Markus H. January 2001 (has links)
Species prescriptions are developed for revegetating abandoned acidic coal overburden seepage sites in the Collie region of Western Australia. The research involved selecting appropriate plant species and determining successful methods of enhancing revegetation. Candidate species were screened for tolerance to acidic overburden materials, local climate conditions and metal toxicity. Methods tested included improving spoil conditions and trialing an alternative method for seeding.Twelve species of native plants were tested for tolerance in two acid overburden materials in pot and field trials. Eucalyptus robusta is the most tolerant, Eucalyptus camaldulensis and Eucalyptus cladocalyx are highly tolerant, Eucalyptus rudis and Melaleuca hamulosa demonstrate potential, provided adequate soil moisture is available.An important growth restriction factor in acid soils is the presence of free aluminium ions. A glasshouse trial performed on seven species for tolerance to aluminium toxicity revealed E. robusta as most tolerant and E. camaldulensis and Kunzea ericifolia a highly tolerant. E. rudis and M. hamulosa are moderately tolerant, but E. cladocalyx and Eucalyptus diversicolor are very sensitive to aluminium.Various methods were trialed to increase growth of seedlings transplanted on to acidic overburden sites. Both commercial cow manure and slow-release fertiliser tablets increase growth, whereas commercial potting mix and lime do not. Inoculation of plants with the ectomycorrhiza fungus Pisolithus tinctorius increases the amount of infection in roots but does not enhance plant growth.Supplementary fertilisation is necessary to maintain growth (nitrogen) and restore chlorophyll production (phosphorus) in fast growing eucalypt seedlings planted into typical acidic spoils. Poor levels of nutrient availability in such acidic sites appear to be the primary factor in ++ / retarding growth. In the absence of supplementation, foliage reddening is observed in several species.An alternative method of seeding dumps is fascining. Prepared dump surfaces may be covered with capsule-laden branchwood of myrtaceous species. Material of the locally available Kunzea ericifolia is effective in producing many seedlings. Subsequent seedling growth is enhanced with fertiliser and lime addition.

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