Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 173 for “"Seam"”.
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Designing for upper seam stability in multi-seam mining
The problem of interaction resulting from mining seams above a previously mined seam has been thoroughly investigated in order to develop and evaluate methods of improving upper seam ground conditions when mining through either active or passive subsidence waves. Design criteria have been developed …
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Microcomputer simulation of near seam interaction
… of coal within 110 feet below a previously mined seam creates interaction effects which can be detrimental to work in the lower seam. These interaction effects are characterized by zones of very high stress and result in floor and roof instability and pillar crushing. Recent developments in the …
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Uplift loaded standing seam roof systems
… predict the failure of an uplift-loaded standing seam roof system. Four sets of full-scale tests were conducted and their results were analyzed along with previous results (Anderson 1991). It was found that by normalizing the data, a reduction factor could be established for each test set …
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Gateroad Design in Overlying Multi-Seam Mines
There are two major design problems for upper seam longwall gateroads operating in a multi-seam environment. The first is to determine the location, magnitude and duration of stress transferred from lower seam mines; and the second is to predict the effect of stress transferred from lower seam …
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Recoverable reserve estimation in multiple seam mines
… In the majority of the world's coalfields, seams are found on multiple horizons, and coal recovery may be significantly reduced depending upon the magnitude of seam interaction. In order to evaluate the effects of interaction in terms of coal losses, a hazard technique has been developed. …
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Stress transfer between multi-seam longwall mines
… will entail the extraction of coal under multi-seam mining conditions. Mine design in such an environment will require the accurate prediction of stress transfer between adjacent seams. The available knowledge on criteria controlling stress transfer has been exhaustively reviewed and critical …
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An optimization of baseball fielder positioning using SEAM
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2024-09-16 without embargo terms
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An optimization of baseball fielder positioning using SEAM
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2024-09-16 without embargo terms
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Standing seam roof system strength under uplift loading
… loading of C- and Z-purlin supported, standing seam metal building roof systems. To achieve this end, eight sets of full-scale roof system tests were conducted. Each test set consisted of a single span base test and a three-span, multi-purlin line, confirming test. The base test method for …
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Interactive prediction software for underlying multi-seam design
An extensive review of multi-seam under-mining literature was conducted and a data base of case studies was compiled. A critical review of the design principles outlined in this literature resulted in the compilation of specific design criteria for the design of lower seam mines. Analysis of this …
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Pillar load transfer mechanisms in multi-seam mining
… pillar load transfer from an overlying seam to subadjacent workings is investigated. Mine geometry and geology are researched as major variables affecting interaction between contiguously placed seams. The thesis includes photoelastic experimentation, finite element modeling, and …
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Forensic research on detecting seam carving in digital images
… of the popular image editing techniques, called ‘seam carving’. To reveal seam carving applied to uncompressed images from the perspective of energy distribution change, an energy based statistical model is proposed as the first work in this dissertation. Features measured global energy of images, …
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The liberation characteristics of Greenside No. 2 seam coal
In South Africa, ever increasing quantities of fine (-0,5 mm) coal are being produced as a result of the increased use of mechanised mining methods. Very few mines beneficiate the fines; in most cases they are discarded. However the fine size of this material suggests that it should be well …
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Further studies of uplift loaded standing seam roof systems
… predict the capacity of gravity loaded standing seam roof systems. However, for uplift loaded standing seam roof systems, the base test method is still being investigated. Previous tests conducted at Virginia Tech in 1990 and 1991 have led to the belief that scatter is inherent in the results of …
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Interaction effects due to subsidence in multiple seam mining
… coal fields contain many contiguously placed seams of coal. Mining in these seams has been active over such an extended period of time that considerable knowledge has been gained in the area of multiple seam mining. It is commonly accepted that the preferred sequence of extracting contiguous …
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Calibrating the LaModel Program for Shallow Cover Multiple-Seam Mines
… finding shallow-cover failure cases for single seam mines necessitated creating a database which also included multiple-seam interactions. In general, with shallow cover, most mines were very successful, unless some type of multiple-seam stress became involved.;An initial analysis of the data …
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Non-destructive evaluation of resistance seam welds by acoustic emission
Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1984
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The effects of the pressure arch upon multiple seam mining
… of Appalachia of many contiguously mineable coal seams. Common practice in mining multiple seams is to extract the seams in a descending order. However, the mining sequence may still be based on seam ownership, availability of the seam and the general economic situation, net on ground control …
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Stability assessment of entry roofs in underlying multiple seam mines
Entry roofs in underlying multiple seam mines are vulnerable to failure under the influence of stress transferred from the upper seam workings. Overburden depth, innerburden thickness, percentage of hard rock in the innerburden and relative location of pillars in the two seams are some of the …
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Layout design for interactive zones in longwall multiple seam mining
… guidelines for the increasingly popular multi-seam longwall method. Entry layouts often depart from the ideal when finally developed. The thesis examines the occurrence of ground control problems, and possibilities for improvements in strata control, in a variety of undermining situations. The …
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