Shear strength characterization of discontinuities is an important concept for slope design in discontinuous rocks. This study presents the development of a methodology for implementing Barton-Bandis empirical shear strength failure criterion in three dimensional distinct element code, 3DEC, and verification of this methodology. Normal and shear deformation characteristics of discontinuities and their relations to the discontinuity surface characteristics have been reviewed in detail. First, a C++ dynamic link library (DLL) file was coded and embedded into 3DEC for modelling the Barton-Bandis shear strength criterion. Then, a numerically developed direct shear test model was used to verify the normal and shear deformation behaviour with respect to empirical results of the Barton-Bandis shear strength criterion. A three dimensional simple discontinuous rock slope was modelled in 3DEC based on Barton-Bandis shear strength criterion. The slope model was first utilized by Mohr-Coulomb failure criterion. Then, with the use of the new model developed here, the effects of the discontinuity surface properties on shear strength were introduced to the slope problem. Applicability of the developed model was verified by three large scale real case studies from different open pit lignite mines of Turkish Coal Enterprises (TKi), namely Bursa Lignites Establishment (BLi) &ndash / 2 cases and &Ccedil / an Lignite Establishment (&Ccedil / Li). The results with the new model option, which allows users to use important discontinuity surface properties like joint roughness coefficient and joint wall compressive strength, compared well with results of previous studies using Mohr-Coulomb failure criterion.

Groundwater can be a critical issue to be considered in civil engineering, mining engineering and interdisciplinary fields. Karstic structures and aquifers enclosing groundwater are potential risks in case they are not studied in detail. Enclosed groundwater can result in floods at pit bottom or can cause instabilities of permanent pit slopes. This study is about analyses of flooding possibility at the pit bottom and possible instabilities of pit slopes in the Elbistan-&Ccedil / &ouml / llolar open cast coal mine due to the presence of a karstic aquifer under the lignite formation. Thickness and permeability of the bottom clay formation under the lignite bed are necessary critical parameters for investigating a possible water rush from a confined aquifer in limestone formation underneath the bottom clay. These parameters were changed, and water flow quantities towards the pit bottom were determined by finite element models. Critical values of these parameters were investigated considering the lack of accurate site investigation information regarding the thickness and permeability of bottom clay. Possible strength loss, fracturing, and thus permeability increase in bottom clay due to a confined aquifer were studied. In flooding and slope stability analyses Phase2 software based on finite element method is used. Results of analyses showed that as reported thickness of bottom clay is around 120 m at the pit bottom and permeability values are in orders of magnitudes of 10-8 m/s, no serious flooding problems are expected to occur unless the thickness of bottom clay layer drops down to around 20 m, and the permeability of this layer reaches an order of magnitude of 10-5 m/s. Mechanical effects of confined aquifer on slopes and bottom clay displacements were investigated, and thus fracturing and failure possibilities of bottom clay and permanent slope were assessed. Slope and pit bottom displacements increased to meter levels for less than 60 m bottom clay thicknesses. Whereas 50-60 m bottom clay thickness can be critical for cracking, 20 m bottom clay thickness was found to be critical for water rush to the pit bottom. With reported bottom clay thickness of 120 m and with 25o slope angle permanent slope factor of safety was found to be 1.2, and this value was not effected unless clay layer thickness drops below 70 m levels. Higher than 32o overall slope angle there will be a risk of slope failure for permanent and production slopes, reflected by safety factors less than one, in the stability analyses.

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.

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.