Fracture toughness is an important rock property for rock fracturing and fragmentation applications. Theory and practice of opening mode (mode I) and shearing mode (mode II) fracture toughness tests are still in a developing stage for the cylindrical rock cores. A new circular plate type test specimen is used for mode II fracture toughness testing on rock cores. This involves a straight edge notched circular plate type core disc geometry under three-point bending load / new method and its associated specimen geometry is referred as straight edge notched disc bend (SNDB) specimen under three-point bending. Mode II fracture toughness results of the tests with this new geometry were compared to the results of the tests commonly employed for mode II fracture toughness testing. Specimen geometries were modeled and mode II stress intensity factors were computed by finite element modeling using ABAQUS program. For comparison purposes, mode II or shearing mode fracture toughness KIIc of two different rock types were determined by different testing methods commonly employed in recent practice. Core specimens of Ankara andesite and Afyon marble rock types were tested with cracked chevron notched Brazilian disc and cracked straight through Brazilian disc specimens under Brazilian type loading, semi-circular bend specimen and straight edge notched disc bending specimen geometries under three-point bending.For all testing groups, cylindrical cores with diameters varying from 7.5 cm to 12.5 cm were prepared with notch lengths changing from 1.5 cm to 2.6 cm. Effect of specimen thickness on mode II fracture toughness was investigated for three different testing methods. Fracture toughness values remained constant when thickness of the specimens was increased for cracked straight through Brazilian disc, semi-circular bend and straight notched disc bend methods. For cracked straight through Brazilian disc method KIIc values of Ankara andesite and Afyon marble were 0.99 MPa&radic / m and 0.86 MPa&radic / m, respectively. Mode II fracture toughness with semi-circular bend specimen was 0.43 MPa&radic / m for andesite and 0.46 MPa&radic / m for marble. When the results of the two three-point bending type tests were compared straight notched disc under three-point bending resulted in higher KIIc values (0.61 MPa&radic / m for andesite and 0.62 MPa&radic / m for marble) than the results found by semi-circular bend tests.

In recent years increasing growth rate of all industrial fields generated an emerging energy demand and consequent environmental problems worldwide. Defining environmental profiles of products and systems using environmental tools, such as Life Cycle Assessment (LCA), is a critical issue for sustainable mining. In order to tackle the increasing environmental challenges and air emissions induced by surface coal mining, alternative material handling options are needed to be evaluated. This research study aims to provide a robust LCA model in selection of the alternative material haulage systems as a decision support system. The main objectives of this thesis study are: i) contributing to the national archived data by gathering data about haulage systems from an open pit coal mine, ii) constructing life cycle inventory from the acquired environmental data, iii) performing life cycle assessment of both material haulage systems in an open pit coal mine according to their environmental burdens, iv) conducting uncertainty assessment, and v) suggesting improvement in stages where emissions are critical. In order to accomplish these objectives, comparative LCA from cradle-to-grave was carried out in SIMAPRO 7.3 to determine life cycle environmental impacts of off-highway mining trucks and belt conveyors in coal transportation. Climate change and acidification were selected as major impact categories considered to be major concerns in mining industry. The results of this study revealed that off-highway trucks had 1.9 times greater impact on acidification category than belt conveyors, on the other hand, belt conveyors had 1.6 times greater impact on climate change. NOx emissions caused 96 percent of the acidification impact. CO2 emissions from fossil fuel combustion led to 95 percent of the climate change effect. The obtained results also indicated that the highest impact on all selected impact categories were generated from the utilization stage of the trucks operated by diesel oil and utilization of belt conveyor systems operated by electricity. The main novelty of this study is that it is one of the first LCA studies in the Turkish mining industry where considerable amount of emissions occur due to material handling. This study also advances the current knowledge about environmentally critical processes in material handling systems and places recommendations for both alternatives aiming better decision making. The results of the study are expected to provide a decision support system for the mining industry.

The aim of this study was to determine the adsorption capacity of activated carbon and organo-zeolites for removal of pesticides in water. In order to prepare organo-zeolite, two kinds of cationic surfactants, namely, hexadecyltrimethyl ammonium bromide (HTAB) and dodecyltrimethyl ammonium bromide (DTAB) were used. Adsorption studies of cationic surfactant on zeolite were investigated in respect to initial concentration of cationic surfactant, time, and temperature. It has been found that the best fitted isotherm equation was Langmuir equation. The observed adsorption rates were found to be equal to the second order kinetic model. The activation energies of cationic surfactant adsorption was determined by using Arrhenius equation.

Dual Gradient Drilling (DGD) system is a promising technology that was developed to overcome the deep water drilling problems occurred due to narrow operating window between pore pressure and fracture pressure. In conventional drilling practice, single mud weight exists from drilling unit to TVD (True Vertical Depth) which creates big hydrostatic pressure in bottom hole ,moreover, minor changes in mud weight results a big pressure changes proportional to the length of hydrostatic column increase with water depth. On the other hand, DGD allows using two different mud weights to get same bottom hole pressure / low gradient drilling fluid from drilling unit to the sea floor and high gradient drilling fluid form the sea floor to TVD, to decrease the effect of water column on mud hydrostatic pressure in TVD. In this thesis, a conventionally drilled deepwater well was redesigned considering the DGD system and drilled virtually to determine the changes of cost of services and materials on total operation budget to prove the positive impact of system on total operation cost. This study not only proved the technical advantages of the DGD system, but also showed economical impact of the system on total drilling cost, by decreasing around 19%.

The aim of the study is to investigate matrix-fracture interaction, gas oil gravity drainage (GOGD) and diffusion mechanisms with CO2, N2 and CH4 gas injection in a fractured system. Effects of injected gas type, initial gas saturation and diffusion coefficient on oil recovery are studied by an experimental and simulation work. In the experimental study, Berea sandstone cores are placed in a core holder and the space created around the core is considered as a surrounding fracture. System is kept at a pressure of 250 psi by CO2, N2 and CH4 gases and at a reservoir temperature of 70 &deg / C. Experiments with cores having similar initial saturations resulted in the highest ndecane recovery in CO2 experiment followed by CH4 and N2. The highest solubility of CO2 in n-decane and density difference between CO2 and CO2-ndecane mixture are considered as the reason of results. CO2 injection tests with n-decane and brine saturated core with and without initial gas saturation indicate that availability of initial gas saturation in matrix increased recovery. A simulation study is continued using CMG (Computer Modeling Group Ltd.) WinProp (Microsoft Windows&trade / based Phase-Behavior and Fluid Property Program) and GEM (Generalized Equation-of-State Model Compositional Reservoir Simulator). Simulation results of CO2 experiment with initial gas show that dominant effect of GOGD decreases and diffusion becomes more effective at final production stages. Simulation study indicates an immediate, sharp decrease in oil saturation in matrix. Oil in matrix migrates into fractures and moves downward as a result of GOGD with gas injection.

The discontinuities play an important role both in design and development stages of many geotechnical engineering projects. Because of that considerable time and capital should be spent to determine discontinuity sets by conventional methods. This thesis present the results of the studies associated with the application of the Remote Sensing (RS) and the development of a methodology in accurately and automatically detecting the discontinuity sets. For detection of the discontinuities, automatic lineament analysis is performed by using high resolution satellite imagery for identification of rock discontinuities. The study area is selected as an Andesite quarry area in G&ouml / lbaSi, Ankara, Turkey. For the high resolution data 8-bit Ikonos Precision Plus with 1 meter resolution orthorectified image is used. The automatic lineament extraction process is carried out with LINE module of PCI Geomatica v8.2. In order to determine the most accurate parameters of LINE, an accuracy assessment is carried out. To be the reference of the output, manual lineament extraction with directional filtering in four principal directions (N-S, E-W, NE-SW, NW-SE) is found to be the most suitable method. For the comparison of automatic lineament extraction and manual lineament extraction processes, LINECOMP program is coded in java environment. With the written code, a location and length based accuracy assessment is carried out. After the accuracy assesssment, final parameters of automatically extracted lineaments for rock discontinuity mapping for the study area are determined. Besides these, field studies carried out in the study area are also taken into consideration.

In this thesis, the results of a number of rock mass classification systems applied to Dim-higway tunnel study area are presented. The tunnel ground was classified according to Rock Mas Rating (RMR), Modified Rock mass Rating (M-RMR), Rock mass quality (Q), Geological Strength Index (GSI) and New Austrian Tunneling Method (NATM). Dim Tunnel has a horse-shoe shape, with a diameter of 10 meters and maximum overburden thickness of 70 meters. During studies, the geological and geotechnical characteristics of the rock mass along the Dim Tunnel route were investigated. The main objective of rock mass classifications carried out in this study was to obtain adequate data that could be used in future excavation and support-design studies. In order to accomplish this task, literature survey was carried out, followed by a comprehensive field study and laboratorytesting. Field studies involved detailed discontinuity surveys of the exposed rock mass at the surface and on the cores taken within 10-20 meters of the borehole above the tunnel. A geological map and a geological cross-section along the tunnel axis were also prepared. Finally, correlations between the results of the rock mass classification systems were made carrying out statistical analyses for the Dim Tunnel study area. The results obtained from the RMR and M-RMR classifications indicate that M-RMR system estimates better rock mass quality ratings at the upper bounds of the rock mass condition, but worst ratings at the lower bounds (RMR is less than 40) as also suggested by the previous studies.

In this study, subsidence analyses were carried out for panels B14, B12, B10, B02, C12, C10, C08 of &Ccedil / ayirhan Lignite Mine using in-situ subsidence measurements. Using the measurements from stations, installed both parallel and perpendicular to panel-advance direction, subsidence profiles were plotted as a function of time and distance from panel center. Horizontal displacement and strain curves were also plotted and compared with subsidence profiles. There are various methods used for subsidence prediction. In this study however, a subsidence model was developed based on empirical model obtained from nonlinear regression analysis. During the analyses SPSS (V.10.0) software was used and the unknown parameters associated with subsidence function were determined for the stations above B14 panel. Since it was too complicated to take all the affecting factors into consideration, only the parameters which could be estimated by statistical evaluation were taken into account during analyses. One significant contribution of this study to subsidence subject was the comparison of the subsidence values measured during this investigation with the values predicted by some other empirical methods. In this study, the structural damages to the pylons installed on ground surface above retreating longwall panels were also investigated by the use of previous studies. Slope as well as horizontal strain changes caused by ground movements due to underground mining were determined. Last but not least, it should be stated another significant contribution of this study to engineering was the collection of a significant database obtained from field measurements.

Research in the field of non-linear optical (NLO) devices lead to an increasing interest in new borate compounds, capable of expanding the frequency range provided by common laser sources. Lithium triborate (LBO) is a newly developed ideal non-linear optical crystal used in laser weapon, welder, radar, tracker, surgery, communication, etc. Borates containing rare-earth elements are of great interest since they are found to be superior in non-linear optical applications. In this study, synthesis and identification of rare-earth doped lithium triborate was carried out. Lithium triborate was produced from the solid-state reaction. LBO was then doped with some rare-earth elements (Gd, La, Y) in several different concentrations. Appropriate quantities of Li2CO3 and H3BO3, weighted separately, were mixed and finely powdered. Then, the mixture was heated at 750 &ordm / C for 14 hrs. The expected reaction is given below. Li2CO3 + 6H3BO3 --&gt / 2LiB3O5 + CO2 + 9H2O Prepared LiB3O5 and Gd2O3, La2O3 and Y2O3 samples were weighed separately at different concentrations and ground together. The mixture was then heated at 750 &ordm / C for 7 hrs. Characterization of the new products was done by X-Ray Diffraction (XRD) and Infrared (IR) analysis. Differential Thermal Analysis (DTA) was used for examination of the thermal properties of the compounds, morphology of new compounds was observed by Scanning Electron Microscopy (SEM). The compounds are then subjected to thermoluminescence (TL) studies. From the XRD studies, no change in the LBO phase related to the addition of rareearth elements was observed. However, peaks of those elements were also become apparent. IR analysis showed that there is no change related to B-O link with the addition of rare earth elements. DTA studies showed that the melting point of LBO decreases with the addition of rare earth elements. In the SEM images, two phases belonging to particles of rare earth elements and lithium triborate were observed clearly. With the TL analysis, it was considered that the samples show dose response but also it was realized that they are affected by fading.

A new testing method was introduced and developed to determine Mode I fracture toughness of disc type rock specimens. The new method was named as Straight Notched Disc Bending and it uses disc specimens under three-point bending. 3D Numerical modeling was carried out with a finite element program ABAQUS to find stress intensity factors for both well-known Semi-circular Bending specimen models and Straight Notched Disc Bending specimen models for varying disc geometries. Both specimen types included notches where a crack front is introduced at the tip of the notch to compute the stress intensity factors. For stress intensity analysis, crack front-upper loading point distance and span length between the two roller supports at the bottom boundary of the specimens were changed. Fracture toughness testing was carried on Ankara G&ouml / lbaSi pink colored andesite for both specimen types / crack front-upper loading point distance and span length between the two roller supports at the bottom boundary of the specimens were changed during the tests. For both specimen geometries, notch lengths changing from 5 mm to 20 mm were used. For each notch length, two different roller supports with span lengths 60 mm and 70 mm were used. For both methods, fracture toughness values determined by using numerically computed stress intensity factors and failure loads obtained from the experiments were very close / the new method was verified by comparing the results. The new method had advantages of lower confining pressure at the crack front and lower stress intensities with a possible smaller crack tip plasticity region.