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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.
11

Structural and Engineering Geological Investigation of Fracture Zones and Their Effect on Tunnel Construction / Struktur- och ingenjörsgeologisk undersökningav förkastningszoner och deras påverkanpå tunnelbyggnation

Alfvén, Linda January 2015 (has links)
This thesis project was conducted in connection with the project, Stockholm’s future sewer pipeline, which is a planned sewer pipe that will run through a tunnel from western to southern Stockholm. This tunnel will pass under Lake Mälaren between Eolshäll and Smedslätten, where there are two faults indicated on the geological map, that could affect the tunnelling and create risks during the construction. Geophysical- and water-loss measurements along with core drilling have been carried out in the area. The objectives of this thesis are to create a structural and engineering geological understanding of the passage beneath Lake Mälaren based on drill core mapping, field work, data from previous investi-gations and 2D-models of the tunnel excavation both within and outside the indicated fault zone. The core mapping supports the existence of one fault zone, which is indicated on the geological map supported by water-losses at several places along the drill core as well as core losses. Field work indi-cated the existence of a conjugate fracture sets.The 2D-models present plastic behaviour of the rock in the fault zone as the worst case scenario during excavation with the highest deformation displacement. The excavation procedure and the tunnel form also play a significant role. Since this thesis highlights some significant risks and problems that can occur during tunnelling, its findings may be useful during the tunnel construction. / Denna uppsats är skriven med koppling till projektet, Stockholms framtida avloppsledning, vilket inkluderar en ny tunnel för transport av avloppsvatten från västra till södra Stockholm. Tunneln kommer att passera under Mälaren mellan Smedslätten och Eolshäll, där det är två förkastningar indikerade på geologiska kartor som kan orsaka stora risker för byggnationen av tunneln. Geofysiska mätningar, kärnborrning och vattenförlustmätning har tidigare utförts i området. Målen för denna uppsats är att skapa en geologisk- och bergmekanisk förståelse för tunnelpassagen under Mälaren utifrån kärnkartering, fältarbete, data från tidigare undersökningar och 2D-modeller av tunneluttag i den indikerade zonen och utanför. Kärnkarteringen stödjer existensen av en förkastningszon som finns på den geologiska kartan. Flertalet vattenförluster är indikerade längs med hela kärnan tillsammans med en del förekomster av kärnförluster. Fältarbetet indikerar på förekomst av ett konjugerande sprickset. 2D-modeller över tunneln visade att olika egenskaper på berget samt hur uttaget av tunneln sker har betydelse för deformationernas storlek. Den här uppsatsen belyser några viktiga problem och risker som kan uppstå under tunnelbyggnationen, dessa upptäckter kan därför vara användbara och värdefulla under hela byggnationen.
12

Rörelseriktning på förkastningszoner i Stocksund och Södermalm / Displacement in Fault Zones in Stocksund and Södermalm

Olausson, Hanna January 2018 (has links)
Stockholm stad är inne i en expansiv fas. En växande befolkning ökar inte bara behovet av ett mer ansvarsfullt markanvändande utan också en välfungerande infrastruktur. Med avseende på detta så har det de senaste åren skett och fortsätter ske, en rad större projekt som inkluderar arbete både direkt i och i nära anslutning till berg. Detta ställer höga krav på förståelse för det berg man jobbar i och därför utförs noggranna geologiska undersökningar innan ett projektarbete tar vid. Denna studie fokuserar på två sådana områden där mycket infrastrukturell aktivitet i berg har förekommit de senaste åren. Undersökningsområde nummer 1 är Stocksund och innehåller data som tagits fram i samband med utbyggnaden av elnätet i projekt City link. Område nummer 2 är Slussen på Södermalm med information som erhållits i samband med ombyggnationen av trafikplatsen. Då omfattande förundersökningar och kartläggningar har gjorts för respektive område har redan befintliga data kunnat användas på nytt i detta arbete. Studien har som syfte att undersöka tidigare förkastningar och deras rörelseriktningar i området. För att göra detta har borrkärnor från respektive lokal analyserats för att hitta rörelseindikatorer som kan påvisa hur förkastningen såg ut när den skedde. Slickenside är en typ av rörelseindikator som kan användas för detta ändamål. I varje borrkärna hittades fem stycken ytor som uppvisade slickenside och som därför har undersökts vidare. / The city of Stockholm is in a phase of expansion. A growing population does not only increase the need of a more responsible usage of land areal but also the need of a high functioning infrastructure. Due to this development a lot of large-scale projects including work in direct and in close contact to rock have been performed or are currently underway. This demands a great deal of knowledge on the certain rock-types involved in said projects and therefore thorough geological investigation takes places before any project can start. This study will focus on two of these areas where a lot of infrastructural activity in rocks have taken place during recent years. Examination area one is in Stocksund and contains data that was maintained in connection with the expansion of the power grid called project “City link”. Area two is located in Slussen, Södermalm where the information comes from the major reconstruction of the traffic juncture. Since several investigations and surveys have been conducted, old data from earlier projects has proven useful for this study. The study aims to investigate previous faults and their sense of movement in the area. In order to do so, drill cores from each site have been analyzed in order to find sense indicators that can provide information about the fault. Slickenside is a kinematic indicator that can be used for this. Each area had one drill core and in each of them five slickensides were identified and examined further.
13

Mineralisering, omvandling och ursprungliga bergarter av borrkärnor från Renströmområdet, Skelleftefältet / Mineralization, alteration and protolith of drill cores from the Renström area, Skellefte district

Dahl, Gustav January 2018 (has links)
Brytning av ekonomiskt värdefulla resurser sker över hela världen och effektiviseras kontinuerligt. Ökad brytning av mineral innebär att lättåtkomliga malmkroppar förbrukas. När de lättåtkomliga kropparna av dessa mineraler använts upp krävs det prospekteringsmetoder för att leta djupare in i jordskorpan. En sådan metod är borrkärnekartering.Syftet var att detaljerat beskriva borrkärnans petrofysiska egenskaper samt lokalisera potentiell ekonomiskt område med hjälp av borrkärnekartering. Två borrkärnor karterades och undersöktes med hjälp av en handhållen XRF. Borrkärnekarterings potential som prospekteringsmetod utvärderades.Malmkropp innehållandes stor del Zn samt Pb, Cu och Fe identifierades i båda borrkärnorna. pXRF och kartering lokaliserade malmkropp i liknande omfång och gradering. Ursprungsbergarter och dess sammansättning identifierades.Prospekteringsmetoder som borrkärnekartering fungerar mycket bra i de fall övergripande information om borrkärnan behövs omgående. Borrkärnekartering är således en effektiv metod som kan användes vid borrplatsen för att kontinuerligt ge information om borrkärnan och således avgöra om borrning ska fortsätta eller avslutas. Prospekteringsmetoden fungerar bäst i kombination med andra metoder, geokemiska eller geofysiska. / Mining of economically important resources is a process happening all over the world and have been increasing in effectiveness during the last century. Increased mining of the resources means that the easily accessed bodies of these minerals is exhausted. Prospecting methods to find new bodies in the ground is then needed. One of these methods is core logging.The goal of the project was to locate potential valuable mineralization. Two different cores were logged and evaluated with a hand held XRF during the project. The effectiveness of core logging as an exploration method was evaluated.Ore body containing large amounts of Zn as well as Pb, Cu and Fe were identified in both drill cores. pXRF and logging gave the same size and grades of the ore body. Protoliths and its composition were identified.Exploration methods like core logging is useful when summary information of the drill core is necessary and the information needs to be given fast. The method is therefore effective in the field at the drill stations to give continuously information about the drill cores being drilled. The method is most effective when combined with other methods like geochemical or geophysical methods.
14

Multi-scale image analysis for process mineralogy

George Leigh Unknown Date (has links)
This thesis primarily addresses the problem of automatic measurement of ore textures by image analysis in a way that is relevant to mineral processing. Specifically, it addresses the following major hypotheses: • Automatic logging of drill core by image analysis provides a feasible alternative to manual logging by geologists. • Image analysis can quantify process mineralogy by physically meaningful parameters. • Multi-scale image analysis, over a wide range of size scales, provides potential benefits to process mineralogy that are additional to those available from small-scale analysis alone, and also better retains the information content of manual logging. • Image analysis can provide physically meaningful, ore-texture-related, additive regionalised variables that can be input to geostatistical models and the definition of domains. The central focus of the thesis is the development of an automatic, multi-scale method to identify and measure objects in an image, using a specially-developed skeleton termed the morphological CWT skeleton. This skeleton is a multi-scale extension of the morphological skeleton commonly used in image analysis, and is derived from the continuous wavelet transform (CWT). Objects take the form of hierarchical segments from image segmentation based on the CWT. Only the Mexican hat, also known as the Laplacian-of-Gaussian, wavelet is used, although other wavelet shapes are possible. The natural scale of each object is defined to be the size scale at which its CWT signal (the contrast between the interior and exterior of the object) is strongest. In addition to the natural scale, the analysis automatically records the mineral composition of both the interior and exterior of each object, and shape descriptors of the object. The measurements of natural scale, mineral composition and shape are designed to relate to: • The size to which ore must be broken in order to liberate objects. • Minerals that need to be separated by physical or chemical means once objects have been liberated. • Capability to distinguish qualitatively different ore-texture types that may have different geological origins and for which different processing regimes may provide an economic benefit. Measurements are taken over size scales from three pixels to hundreds of pixels. For the major case study the pixel size is about 50 µm, but the methodology is equally applicable to photomicrographs in which the pixel size is about 4 µm. The methodology for identifying objects in images contributes to the field of scale-space image segmentation, and has advantages in performing the following actions automatically: • Finding optimal size scales in hierarchical image segmentation (natural scale). • Merging segments that are similar and spatially close together (although not necessarily touching), using the structure of the morphological CWT skeleton, thus aiding recognition of complex structures in an image. • Defining the contrast between each segment and its surrounding segments appropriately for the size scale of the segment, in a way that extends well beyond the segment boundary. For process mineralogy this contrast quantifies mineral associations at different size scales. The notion of natural scale defined in this thesis may have applications to other fields of image processing, such as mammography and cell measurements in biological microscopy. The objects identified in images are input to cluster analysis, using a finite mixture model to group the objects into object populations according to their size, composition and shape descriptors. Each image is then characterised by the abundances of different object populations that occur in it. These abundances form additive, regionalised variables that can be input into geostatistical block models. The images are themselves input to higher-level cluster analysis based on a hidden Markov model. A collection of images is divided into different ore texture types, based on differences in the abundances of the textural object populations. The ore texture types help to define geostatistical domains in an ore body. Input images for the methodology take the form of mineral maps, in which a particular mineral has been assigned to each pixel in the image prior to analysis. A method of analysing unmapped, raw colour images of ore is also outlined, as is a new model for fracture of ore. The major case study in the thesis is an analysis of approximately 1000 metres of continuously-imaged drill core from four drill holes in the Ernest Henry iron-oxide-copper-gold ore deposit (Queensland, Australia). Thirty-one texture-related variables are used to summarise the individual half-metres of drill core, and ten major ore texture types are identified. Good agreement is obtained between locations of major changes in ore type found by automatic image analysis, and those identified from manual core logging carried out by geologists. The texture-related variables are found to explain a significant amount of the variation in comminution hardness of ore within the deposit, over and above that explained by changes in abundances of the component minerals. The thesis also contributes new algorithms with wide applicability in image processing: • A fast algorithm for computing the continuous wavelet transform of a signal or image: The new algorithm is simpler in form and several times faster than the best previously-published algorithms. It consists of a single finite impulse response (FIR) filter. • A fast algorithm for computing Euclidean geodesic distance. This algorithm runs in O(1) arithmetic operations per pixel processed, which has not been achieved by any previously published algorithm. Geodesic distance is widely used in image processing, for segmentation and shape characterisation.
15

A 1700-year history of fire and vegetation in pine rocklands of National Key Deer Refuge, Big Pine Key, Florida charcoal and pollen evidence from Key Deer Pond /

Albritton, Joshua Wright. January 2009 (has links)
Thesis (M.S.)--University of Tennessee, Knoxville, 2009. / Title from title page screen (viewed on Mar. 11, 2010). Thesis advisor: Sally P. Horn. Vita. Includes bibliographical references.
16

Dynamics of the British Ice Sheet and prevailing hydrographic conditions for the last 175,000 years : an investigation of marine sediment core MD04-2822 from the Rockall Trough

Hibbert, Fiona Danielle January 2011 (has links)
This study presents a stratigraphic investigation of the marine sediment core MD04-2822 from the Rockall Trough (56° 50.54' N, 11° 22.96' W; 2344 m water depth). This core is currently the only available high resolution record for the calibration of Late Quaternary sedimentary sequences of the British (Hebridean) margin. It therefore offers an unprecedented archive of changing sedimentological and climatological conditions for the last 175,000 years. The high resolution, multi-proxy records have enabled surface and deep water conditions within the Rockall Trough to be reconstructed. In addition, the fluctuating nature of ice-rafted debris (IRD) inputs to the MD04-2822 site allows a first order attempt of BIS dynamics for the entirety of the last glacial period (i.e. from the demise of the last interglacial to the decay of the Devensian/Weichselian ice sheet) as well as the majority of the penultimate (Saalian/MIS 6) glaciation. Sediment core MD04-2822 is ideally located to capture the dynamics of the British Ice Sheet (BIS) via a continuous record of IRD and fine-grained terrigenous inputs. Fundamental to this is the construction of a robust chronology. This was achieved via: the correlation of the benthic δ¹⁸O record to a global δ¹⁸O stack (SPECMAP); the correlation of the surface proxies (% N. pachyderma (sinistral) and XRF Ca) to the Greenland δ¹⁸O and Antarctic methane ice core records; and radiocarbon dating. This chronology was validated using both radiocarbon dating and tephra horizons. An evaluation of the event stratigraphy approach used in the construction of the MD04-2822 chronology is presented. The marine record provides a valuable archive of past ice sheet dynamics as much terrestrial evidence is removed or obscured by subsequent ice sheet oscillations MD04-2822 provides the first evidence for the expansion of the BIS onto the Hebridean Margin during MIS6 (thereby confirming previous long-range seismic correlations). The continuous sedimentation at MD04-2822 enabled the first insights into the early dynamics of the last BIS. Increases in IRD and fine grained terrigenous material delivered to the MD04-2822 at ca. 72 kyr represent the first significant delivery of material from the BIS across the continental shelf to the core site. The BIS would therefore have attained a marine calving margin by this time. A multi-proxy investigation of provenance was undertaken, however unequivocal provenance determinations remain problematic. The location of the core suggest the proximal BIS as the most likely source of terrigenous inputs. The expanded nature of the MD04-2822 sediments during the penultimate deglacial (Termination II) provides the first details of BIS dynamics for this period: the interplay of large inputs of freshwater from the decay of the Saalian (MIS 6) ice sheets (including the BIS) upon the surface and deep water circulation of the North Atlantic is investigated. In addition, sub-orbital climatic variability is documented at this location throughout the last interglacial (MIS 5e) and appears to be an intrinsic feature of both the N.E. Atlantic surface and deep water circulation of the last 175 kyr.
17

Classification of Drill Core Textures for Process Simulation in Geometallurgy : Aitik Mine, Sweden

Tiu, Glacialle January 2017 (has links)
This thesis study employs textural classification techniques applied to four different data groups: (1) visible light photography, (2) high-resolution drill core line scan imaging (3) scanning electron microscopy backscattered electron (SEM-BSE) images, and (4) 3D data from X-ray microtomography (μXCT). Eleven textural classes from Aitik ores were identified and characterized. The distinguishing characteristics of each class were determined such as modal mineralogy, sulphide occurrence and Bond work indices (BWI). The textural classes served as a basis for machine learning classification using Random Forest classifier and different feature extraction schemes. Trainable Weka Segmentation was utilized to produce mineral maps for the different image datasets. Quantified textural information for each mineral phase such as modal mineralogy, mineral association index and grain size was extracted from each mineral map.  Efficient line local binary patterns provide the best discriminating features for textural classification of mineral texture images in terms of classification accuracy. Gray Level Co-occurrence Matrix (GLCM) statistics from discrete approximation of Meyer wavelets decomposition with basic image statistical features[PK1]  (e.g. mean, standard deviation, entropy and histogram derived values) give the best classification result in terms of accuracy and feature extraction time. Differences in the extracted modal mineralogy were observed between the drill core photographs and SEM images which can be attributed to different sample size[PK2] . Comparison of SEM images and 2D μXCT image slice shows minimal difference giving confidence to the segmentation process. However, chalcopyrite is highly underestimated in 2D μXCT image slice, with the volume percentage amounting to only half of the calculated value for the whole 3D sample. This is accounted as stereological error. Textural classification and mineral map production from basic drill core photographs has a huge potential to be used as an inexpensive ore characterization tool. However, it should be noted that this technique requires experienced operators to generate an accurate training data especially for mineral identification and thus, detailed mineralogical studies beforehand is required. / Primary Resource Efficiency by Enhanced Prediction (PREP) / Center for Advanced Mining and Metallurgy (CAMM)
18

En ansats mot förenklad sprickkartering av borrkärna / An approach towards a simplified joint mapping of drill cores

Clarin, Viktoria January 2018 (has links)
Detta examensarbete är en ansats mot en förenklad metod för sprickkartering i borrkärna och utvärderar huruvida en förenklad metod är tillämpbar vid projekt som anläggs under aktiv design och tid är en kritisk faktor. Det föreliggande arbetet är en studie baserad på data från Boliden Mineral AB, från undersökningar utförda i syfte att lokalisera en lämplig, lågpermeabel bergvolym för anläggandet av ett slutförvar för miljöfarligt avfall. Vattenflöde i kristallin bergmassa, liksom den i Sverige, förmodas traditionellt påverkas mest av sprickornas karaktär så som sprickdensitet, sprickvidd, råhet, sprickfyllning etc. Vidare påverkar sprickegenskaperna bergmassans hållfasthet, varför karaktärisering av bergmassan utgör en central roll vid byggande i berg. Effektivisering av sprickkartering under aktiv design undersöktes genom att utvärdera hur väl de parametrar som används vid karaktärisering verkar för identifiering av vattenförande strukturer. Vidare utvärderades möjligheten att minska antalet sprickor att kartera och karaktärisera vid den fysiska kärnan. Resultat i denna studie visar inte några tydliga kopplingar mellan mätsektionernas hydrauliska konduktivitet (K) och de individuella karterade parametrarna. Osäkerheterna är dock stora då mätsektionerna för de hydrauliska testerna utgörs av 10 m för uppskattande av K, som dessutom påverkas av storskaliga företeelser (t.ex. grad av sammankoppling) som vidare inte är möjligt att uppskatta från borrhålsdata. Fjärrkartering av borrhålsfilm underestimerar överlag bergkvaliteten för de tre borrhål som analyserades. En förenklad metod med ett representativt urval sprickor för fysisk kartering beskriver fördelningen av parametervärden väl, vid jämförelse mot en fullständig fysisk kartering för två borrkärnor. Lerfyllda sprickor och höga Ja-värden överestimeras dock vid den förenklade karteringen vilket potentiellt kan leda till en mer konservativ förstärkningsåtgärd än nödvändigt. Fler studier behöver dock genomföras för att utvärdera huruvida den förenklade metoden kan reflektera parametervärdenas fördelning för individuella sprickgrupper. Vidare krävs ytterligare undersökningar för utvärdering av hur robusta de presenterade metoderna är vid kartering av borrkärnor med högre sprickighet än de som använts för analys i denna studie. / This master thesis is the inception of a simplified method for logging fractures in drill holes and comprises an evaluation on whether a simplified method is applicable for projects where the observational method is used and time is a critical factor. The following work is a study based on data from Boliden Mineral AB, acquired from investigations for locating a suitable, low-permeable rock mass for a repository for hazardous waste. Water flow in crystalline bedrock, such as that found in Sweden, is traditionally thought to be most influenced by fracture characteristics like fracture density, aperture, roughness, fillings etc. Moreover, these same characteristics influence the rock mass strength, which is why the characterization of fractures is fundamental for construction in rock. To improve efficiency of fracture logging in projects maintained under the observational method, an evaluation on how well the quantified fracture characteristics work for identification of large-scale water bearing structures was performed. Furthermore, the possibility of decreasing the number of fractures to log and characterize in the core was investigated.  The results show no apparent correlations between hydraulic conductivity (K) in test sections and the individually mapped parameters. However, the uncertainties are significant, mainly because of the large sections in which the hydraulic tests were conducted, but also because of largescale features influencing K (e.g. interconnectivity) which are not possible to estimate from core data.  Remote logging of borehole images generally underestimates the quality of the rock mass for the three analyzed boreholes. A simplified method with a representative selection of fractures for physical core logging was found to describe the distribution of parameter values well, when compared to a complete physical core log for two drill cores. Clayfillings and high Ja -values are however overestimated when the simplified method is applied which may lead to a more conservative reinforcement measure than necessary. However, more studies need to be carried out to evaluate whether the simplified method can reflect the distribution of parameter values for individual fracture sets. Moreover, additional studies are required to evaluate the robustness of the suggested simplified methods in drill cores from areas of more heavily fractured bedrock than those analyzed in this study.
19

Zpracování komplexního karotážního měření / Data processing of well log complex

Hanák, David January 2018 (has links)
This thesis is focused on the problem of the determination of shear surfaces of slope instabilities (including fossil ones) from the results of the complex of logging methods. It describes the steps taken during data measurement, processing, and interpretation. All the data comes from the measurements conducted in the boreholes carried out for the geotechnical survey of the sliding area in the immediate proximity of the D8 highway or measurements in a well from the Děčín-Loubí locality. On the second mentioned locality, due to a different well construction, a more extensive logging complex could be carried out. After locating shear surfaces in a slope instability, a comparsion was made to determine whether the results in neighboring boreholes corresponded to each other, and to evaluate which methods (or combination of methods) suits best for the task.
20

Hyperspectral drill-core scanning in geometallurgy

Tusa, Laura 01 June 2023 (has links)
Driven by the need to use mineral resources more sustainably, and the increasing complexity of ore deposits still available for commercial exploitation, the acquisition of quantitative data on mineralogy and microfabric has become an important need in the execution of exploration and geometallurgical test programmes. Hyperspectral drill-core scanning has the potential to be an excellent tool for providing such data in a fast, non- destructive and reproducible manner. However, there is a distinct lack of integrated methodologies to make use of these data through-out the exploration and mining chain. This thesis presents a first framework for the use of hyperspectral drill-core scanning as a pillar in exploration and geometallurgical programmes. This is achieved through the development of methods for (1) the automated mapping of alteration minerals and assemblages, (2) the extraction of quantitative mineralogical data with high resolution over the drill-cores, (3) the evaluation of the suitability of hyperspectral sensors for the pre-concentration of ores and (4) the use of hyperspectral drill- core imaging as a basis for geometallurgical domain definition and the population of these domains with mineralogical and microfabric information.:Introduction Materials and methods Assessment of alteration mineralogy and vein types using hyperspectral data Hyperspectral imaging for quasi-quantitative mineralogical studies Hyperspectral sensors for ore beneficiation 3D integration of hyperspectral data for deposit modelling Concluding remarks References

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