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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.
31

The Contribution of Geomechanics and Engineering Geology to Mine Enterprise Value

HORDO, JONATHAN 08 November 2011 (has links)
The objective of this thesis is to identify the value of geomechanics and engineering geology to mine enterprise value for hardrock underground mines. It was decided that the most effective way to highlight the value of geomechanics and engineering geology was by identifying an increase in expenditure that could be economically justified in the present to mitigate the cost of a future event, thus providing a means for showing the economic value of the work performed. Cost models were generated for several events based on the direct cost, value of ore lost and decline in value of ore due to the event. A cost associated with fatalities was also included. Six rockburst events were developed into cost models from publicly available information. A further 13 were developed from confidential information provided by mining companies, bringing the total number of events analyzed to 19. A probabilistic approach was then taken to identify the probability of a rockburst with a certain magnitude occurring and, if an event occurs, the probability it will cause damage. The former is based on the Gutenberg-Richter Frequency-Magnitude relationship while the latter was derived from Unusual Occurrence Reports provided by the Ontario Ministry of Labour. Three case studies were then developed to show how to use the average cost of a rockburst event in conjunction with the probability analysis to arrive at an increase in expenditure above baseline spending. It was found that the total average cost of a rockburst based on the 19 events analyzed from 13 mines in 4 different countries for events occurring between 1984 and 2009 is $35.4 million (2010 CAD) with a range of $1.1 to $263.5 million (2010 CAD). Using the probabilistic method outlined above and cost models from the specific region involved, the increase in expenditure for the Ontario hard rock underground case study, Mine A and Mine B was found to be $12.1 million (2010 CAD), $5 million (2010 CAD) and $4.0 million (2010 CAD) respectively. / Thesis (Master, Mining Engineering) -- Queen's University, 2011-11-06 14:03:21.589
32

Aspects of the engineering geology of Maputo City, Mozambique.

Vicente, Enoque Mendes. January 2011 (has links)
The geological formations of Maputo City, which are mainly unconsolidated materials with soil like properties, are described in terms of their engineering geological and geotechnical characteristics with relevance to their distribution patterns and spatial trends. Problematic conditions such as collapse potential characteristics, loose aeolian sand dune deposits and loose sand plains characterize many of the materials. The geological characteristics combined with anthropogenic interference such as intensive urbanization with inappropriate land use, construction in sensitive areas like steep sandy slopes has led to many problems including slope stability. Foundation problems with building settlement and gully erosion also occur. The aim of this research was to study the engineering geological characteristics and the geotechnical properties of the geological formations of Maputo City and various related problems. Special relevance has been given to the understanding of three specific problems: building damage, gully erosion and slope instability. The geological formations are predominantly sandy (coarse to very fine sand) with very low clay content, are non-plastic and are classified as from the group SP-SM which are poorlygraded sand with silt. The majority of the materials are loose and normally consolidated with a high level of residual strength. Assessment of collapse settlement through double consolidation technique indicated soil compressibility and significant sensibility to collapse upon wetting. Truly collapsible soils that show full collapse of the soil structure were identified in 33% of the tested materials where the highest collapse behaviour reached values above 5%, predicted to cause moderate trouble in foundation design. Some of the bonded materials are bonded (evident in 67% of samples tested). Bonding was confirmed by comparing the compressibility of the undisturbed and remoulded samples. The remoulded samples showed a significantly higher compression than that of the bonded materials as part of the stress applied is carried by the bonds themselves, as the bonded material is stiffer than the same without bonds. The curves of the remoulded samples were used to establish the limit between the stable and meta-stable states of the material. A qualitative evaluation of the erosion susceptibility was investigated by physical tests such as the crumb test, shear strength and chemical indicators while a quantitative evaluation of the erodibility characteristics was obtained using a flume test. Some correlations were found between the results of various methods. Almost all samples that were found to be dispersive with ESP were also dispersive with TDS vs. %Na and SAR. Results of the flume erodibility test have very little correlation with the chemical properties related to dispersion revealing that the erosion susceptibility and gullying in Maputo City have more relation to the physical processes than to the dispersion related chemical properties of the soils. The positive identification of dispersive and erodible soils can only be carried out using a combination of various techniques. Therefore, a new rating system for erosion susceptibility of sandy soils combining the physical and chemical factors of dispersion is proposed including the flume test, crumb test, TDS/%Na, SAR and ESP. The proposed rating system was applied to the tested soils of Maputo City. Fifteen samples (83% of the rated samples) were classified with intermediate susceptibility to erosion while 3 samples (17%) were classified as having a low susceptibility to erosion. The highest rating scores were obtained by the same samples that showed dispersive behaviour with SAR, ESP and TDS/%Na. This group of samples was of intermediate erodibility in the flume test. The slope instability mechanisms observed in Maputo City are predominantly rotational failures with a mass of soil sliding along a curved surface of rupture followed by sand flow at the toe as failure occurs in the presence of excess water. Four groups of factors account for the slope instability problems in Maputo City: geomorphological causes, physical and meteorological causes, geological and geotechnical properties of soils, and anthropogenic causes. The mechanism of failure is mostly due to the loss of matric suction of soils in the presence of rainwater and possibly from destruction of bonding agents. Factors of safety values indicate that the slopes are generally unstable with the control being the slope angle. The slopes in the Polana-Caniço and Ferroviário Quarters show high factor of safety values but is the area most affected by slope instability. Slope failure in these areas is intrinsically caused by anthropogenic factors related to inappropriate land use planning. The gully sidewalls are unstable as the slope created is very steep. The slope at Friedrich Engels Avenue causes most concern due not only to the slope height and angle but also to the size and number of buildings constructed at the crest, mainly high rise buildings along the Julius Nyerere Avenue, the integrity of which could be threatened by a landslide event (this slope has recently been affected by active landslides). / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2011.
33

The effect of grout and casing on amplitude measurements for borehole seismic testing

Mills, Stephanie Maria 05 1900 (has links)
No description available.
34

The influence of spatial variability on the geotechnical design properties of a stiff, overconsolidated clay.

Jaksa, Mark B January 1995 (has links)
The research presented in this thesis focuses on the spatial variability of the Keswick and Hindmarsh Clays within the Adelaide city area. Keswick Clay is locally significant since many of Adelaide's multi-storey buildings are founded directly on it, and internationally significant, since it has been shown by Cox (1970), that this clay exhibits remarkably similar properties to those of the well-documented London Clay. The assessment of the small-scale variability of the undrained shear strength of these clays is based on measurements obtained using the electrical cone penetration test (CPT), and a micro-computer based data acquisition system, designed specifically for this study. A significant feature of the data acquisition system is that it enables measurements to be obtained at intervals of 5 mm, both reliably and efficiently. The development of the data acquisition system is discussed, and the accuracy of its measurements is examined. The small-scale variability of the undrained shear strength of the Keswick Clay is based on more than 200 vertical CPTs, performed within an area of 50 X 50 metres at a site located in the Adelaide city area. The CPTs were spaced at lateral intervals varying between 0.5 and 5 metres, with each vertical CPT extending to a typical depth of 5 metres. In addition, the small-scale horizontal spatial variability of the Keswick Clay is examined using an electrical cone penetrometer driven horizontally into the face of an embankment, again located within the Adelaide city area. The accuracy of the CPT measurements is examined, and discussion is given of the shortcomings associated with a commonly used technique, by Baecher (1982), for estimating the random measurement error associated with various test procedures. The assessment of the large-scale spatial variability of the undrained shear strength of the Keswick and Hindmarsh Clays is founded on a data base of geotechnical engineering properties, compiled from a number of consulting engineering practices and government instrumentalities. The data base, known as KESWICK, contains approximately 160 site investigations, 380 boreholes, and 10,140 measurements obtained from a number of different laboratory and in situ tests. In addition, KESWICK is used to establish generalised trends and bounds, associated with the various geotechnical engineering design properties contained within the data base. The techniques of random field theory and geostatistics are used to quantify, model and predict the spatial variability of the Keswick and Hindmarsh Clays. These techniques are compared with one another in order to assess the suitability and shortcomings of each, when applied to the study of the spatial variability of geotechnical engineering materials. Furthermore, a number of specifically-written computer programs, which were developed to enable the various spatial variability analyses to be performed, are discussed. It is demonstrated that the lateral undrained shear strength of the Keswick Clay, within the Adelaide city area, exhibits a nested structure; that is, one which is the compound effect of several genetic sources of spatial variation. In addition, it is shown that this nested structure can be adequately modelled by means of a spherical semivariogram model. The nested structure is used, together with the kriging estimation process, to provide preliminary estimates of the undrained shear strength of the Keswick Clay, within the Adelaide city area. The analyses demonstrate that the nested model and the kriging process provide a useful facility for generating preliminary estimates of the strength of the clay. Finally, the significance of the spatial variability of the undrained shear strength of clay soils is examined, with reference to the design of embankments and pile foundations. It is demonstrated that the correlation distance can greatly influence the design of each of these geotechnical systems. / Thesis (Ph.D.)--Dept. of Civil and Environmental Engineering, 1995.
35

Investigation of the end bearing performance of displacement piles in sand /

Xu, Xiangtao. January 2007 (has links)
Thesis (Ph.D.)--University of Western Australia, 2007.
36

The effect of high groundwater level on pavement subgrade performance

Zhang, Chaohan. Ping, W. V. January 2004 (has links)
Thesis (Ph. D.)--Florida State University, 2004. / Advisor: Dr. W. Virgil Ping, Florida State University, College of Engineering, Dept. of Civil and Environmental Engineering. Title and description from dissertation home page (viewed Sept. 23, 2004). Includes bibliographical references.
37

A critical appraisal of regional geotechnical mapping in South Africa

Kleynhans, Ilse. January 2005 (has links)
Thesis (M. Sc.(Geology))--University of Pretoria, 2002. / Summaries in Afrikaans and English. Includes bibliographical references.
38

The effect of temperature on mine rocks

Snider, James Wilson, 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 June 29, 2010) Includes bibliographical references (p. 50-51).
39

Rock stress determination in Hong Kong Island by using hydraulic fracturing method /

Tang, Yin-tong. January 2005 (has links)
Thesis (M. Sc.)--University of Hong Kong, 2005.
40

Zoneamento geotécnico do sítio urbano do município de Rio Branco/AC e seus arredores, para fins de planejamento com ênfase à expansão urbana, através do sensoriamento remoto /

Maia, Maria do Socorro Oliveira. January 2003 (has links)
Orientador: Paulina Setti Riedel / Banca: Maria José Brollo / Banca: Iandara Alves Mendes / Resumo: As características geotécnicas do solo, na maioria dos casos, não são consideradas nas intervenções feitas na estrutura urbana, pôr conseguinte também não as são nas expansões urbanas. Como conseqüência disso, verificam-se freqüentemente problemas como movimentos de massa, inundações, assoreamento de rios e igarapés, e erosões. O mapeamento geotécnico surge então como uma ferramenta indispensável para auxiliar o planejamento das intervenções necessárias para acompanhar o rápido crescimento urbano. Na obtenção do zoneamento geotécnico de uso geral, através da utilização do Sensoriamento Remoto, de nossa área de estudo-Sítio urbano do Município de Rio Branco/Ac e seus arredores, foram desenvolvidas três etapas. A primeira etapa consistiu na realização da compartimentação fisiográfica da área com base na análise de elementos texturais de relevo e drenagem e de suas estruturas em imagens fotográficas, obtendo-se assim as unidades básicas de compartimentação (UBC's). Na segunda etapa, estas unidades foram caracterizadas em função de cinco fatores geotécnicos (alterabilidade, permeabilidade, declividade, tipo do material do manto de alteração e espessura do manto de alteração) considerados básicos para subsidiar a avaliação das unidades quanto ao seu potencial de uso. Na terceira etapa as unidades básicas de compartimentação são classificadas quanto ao grau relativo de aptidões /restrições para fins de expansão urbana. / Abstract: Geotechnical characteristics of the soil are rarely taken into consideration when interventions are made in the urban structure, nor, consequently, in urban expansions. As a consequence, there are often problems with landslides, floods, silt accumulation in rivers and sand bars and erosion. Geotechnical mapping has emerged as an indispensable tool to help plan the interventions needed to keep up with rapid urban growth. In this study, three stages were developed to obtain geotechnical zoning for general use in the study area, urban area of the Municipality of Rio Branco, in the state of Acre, using remote sensing. The first stage involved carrying out physiographic subdivision of the area based on analysis of textural elements of the relief and drainage system, and of their structures in photographic images, thus obtaining basic units of sub-division . In the second stage, these units were characterized according to five geotechnical factors (alterability, permeability, slope, type of material of the mantle of alteration, and thickness of the mantle of alteration) considered to be basic for the evaluation of the units with respect to their potential use. In the third stage, the basic units of sub-division were classified according to their relative degree of suitability/restrictions for urban expansion. / Mestre

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