In this thesis, studies associated with the stability analyses of the box-shaped dump-site culvert constructed in Tinaz Surface Mine of Turkish Coal Enterprises (TKi) are presented. In addition, stability conditions of other culvert alternatives are evaluated. Existence of creeks in a surface mining area is a significant factor to be considered in selection of dump-site location. Since, the dumped overburden material on the valley acts as a barrier and behaves like a dam causing flood problem behind the dump-site. TKi engineers prevented the flood potential that might have occurred behind the dump-site by constructing a 480-meter long reinforced-concrete culvert on the downstream of Gevenez Creek Valley. However, considerable amount of deformations occurred in the first 100 meters of the culvert, as a result of overburden material being replaced on this structure. In order to determine the failure mechanism associated with the culvert, a series of numerical modeling analyses were carried out utilizing back analysis technique. The validity of the numerical model was justified by convergence measurements and observations carried out inside the culvert as overburden material being replaced on the stable part of this structure. Finally, based on the numerical model developed, the stability of other culvert alternatives that could be used in future projects were evaluated considering different embankment conditions (positive projecting and negative projecting), bedding conditions (impermissible, ordinary, first-class and concrete cradle), culvert shapes (box and circular) and dumping conditions.

The production of multi-component cement from clinker and two additives such as trass and blast furnace slag has now spread throughout the world. These additives are generally interground with clinker to produce a composite cement of specified surface area. The grinding stage is of great importance as it accounts for a major portion of the total energy consumed in cement production and also as it affects the quality of composite cements by the particle size distribution of the individual additives produced during grinding. This thesis study was undertaken to characterize the breakage properties of clinker and the additives trass and slag with the intention of delineating their grinding properties in separate and intergrinding modes. Single particle breakage tests were conducted by means of a drop weight tester in order to define an inherent grindability for the clinker and trass samples in terms of the median product size ( ). In addition, a back-calculation procedure was applied to obtain the breakage rate parameters ( ) of perfect mixing ball mill model using industrial data from a cement plant. Kinetic and locked-cycle grinding tests were performed in a standard Bond mill to determine breakage rates and distribution functions for clinker, trass and slag. Bond work indices of these cement components and of their binary and ternary mixtures were determined and compared. Attempts were made to use back-calculated grinding rate parameters to simulate the Bond grindability test. The self-similarity law was proved to be true for clinker and trass that their shapes of the self-similarity curves are unique to the feed material and independent of the grinding energy expended and overall fineness attained. The self-similar behaviour of tested materials will enable process engineers to get useful information about inherent grindability and energy consumption in any stage of the comminution process. The parameters, and indicating the degree of size reduction were defined with different theoretical approaches as a function of energy consumption by using single particle breakage test data of clinker and trass. The breakage distribution functions were found to be non-normalizable. On the other hand, the breakage rate functions were found to be constant with respect to time but variable with respect to changing composition in the Bond ball mill. These variations are critical in computer simulation of any test aiming to minimize the experimental efforts of the standard procedure. As a result of the back calculation of breakage rate parameters for clinker and trass samples in the Bond mill, no common pattern was seen for the variation of the rate parameters. Therefore, computer simulation of the Bond grindability test did not result in an accurate estimation of the Bond work index.

Size reduction processes, particularly fine grinding systems, in mineral processing and cement production plants constitute a great portion of energy consumption and operating costs. Therefore, the grinding systems should be designed properly and operated under optimum conditions to achieve productive and cost effective operations. The use of simulation based on kinetic mathematical models of grinding has proven useful in this respect. The kinetic models contain two essential parameters, namely, breakage rate and breakage distribution functions, that are to be determined experimentally, and preferably in laboratory, or by back-calculation from the mill product size distribution for a given feed size distribution. Experimental determination of the breakage parameters has been mostly carried out in laboratory batch mills using one-size-fraction material. The breakage rate parameter is obtained from the disappearance rate of this one-size-fraction material, while the breakage distribution parameters are estimated from the short-time grinding of the same material. Such laboratory methods using one-size fraction material, however, are not truly representative of industrial continuous mill operations where the mill contents have a distribution of particle sizes. There is evidence in the literature that the size distribution of the mill contents affects the breakage parameters. This thesis study was undertaken with the main purpose of investigating the effect of the size distribution of the mill hold-up on the brekage parameters of quartz and calcite minerals in lockedcycle dry grinding experiments. The locked-cycle and one-size-fraction experiments were performed in the Bond ball mill instrumented with a torque-measuring device. Different closing screen sizes were used in the locked-cycle work to produce different size distributions of the mill hold-up, and the operating conditions were changed in the one-size-fraction experiments to obtain different power draws. Particle breakage parameters were assessed for these changing conditions. Prior to the experiments related to the main purpose of the study, preliminary experiments were conducted for two reasons: (i) to find the power draw of the Bond mill in relation to the operating conditions with the intention of eliminating the use of costly torque-measuring devices by others / and (ii) to find the most accurate estimation method of breakage distribution functions among the three existing methods, namely, the &ldquo / zero-order production of fines&rdquo / method, the BII method, and the G-H method. The G-H method was found to be more appropriate for the current study. The locked-cycle grinding experiments revealed that the breakage rate function of coarse fractions increased with increasing proportion of fines in the mill hold-up. Breakage distribution functions were found to be environment-dependent and non-normalizable by size in one-size-fraction and locked cycle grinding experiments. It was concluded that the cumulative basis breakage rate function could sufficiently represent the breakage characteristics of the two studied materials in a wide range of operating conditions. Therefore, it would be more appropriate to evaluate the breakage characteristics of materials ground in ball mills by linearized form of the size-discretized batch grinding equation using single parameter instead of dealing with two parameters which may not be independent of each other.

ABSTRACT DISCUSSION AND EVALUATION OF MINING AND ENVIRONMENT LAWS OF TURKEY WITH REGARD TO EU LEGISLATION Turkey is trying to become a member of the European Union. Within this frame, studies are proceeding for harmonization of the Turkish legislation with the EU legislation. European legislation might have positive or negative impact on the mineral extraction industry and national mining law. Since there is no title directly related to mining policy in the EU legislation the mining policy of EU was evaluated especially under the titles&ldquo / energy&rdquo / and &ldquo / environment&rdquo / . In this thesis, the Turkish mining regulations and the environmental aspects of the mining activities have been investigated and discussed in comparison with those of EU. The latest developments about mining sectors of Turkey and EU have been evaluated and the comparison between EU directives and Turkish laws and regulations about mining have been made. In this study, modifications that should be realized in laws and regulations and measures that should be taken by Turkey as a candidate country for EU discussed and some proposals have been made.

In this study, an attempt has been made to hydrometallurgical extraction of cobalt and nickel by atmospheric pressure sulphuric acid leaching and a pug-roast-leach process using two stage roasting for lateritic ore. The ore used in the study was obtained from &Ccedil / aldag Lateritic Ore, Manisa, Turkey. The metal contents of the ore are 2.1 % Ni, 0.12 % Co, 32.45 % Fe, 1.01 % Mn, 2.58 % Cr, 0.78 % Mg and 1.01 % Al. The reserve of lateritic ore deposit is approximately 40 million tonnes. In the study, first sulphuric acid leaching was applied at atmospheric pressure for leaching the &Ccedil / aldag lateritic ore. The effect of various parameters, such as leaching time, leaching temperature, particle size, pulp density and acid strength on Ni and Co extractions were determined. By leaching at 80oC for 40 wt % H2SO4 addition of ore, 1/3 pulp density, Ni and Co extractions were found 44.49 % and 53.03 % respectively, yielded a pregnant solution containing 3.11 g/L Ni and 0.12 g/L Co. But the result of atmospheric pressure sulphuric acid leaching was considered insufficient from the recovery point of view. In the pug-roast-leach process, which is consisted of a two stage roasting followed by water leaching, decomposition temperature differences of sulphates of cobalt, nickel and iron are exploited. In this process, amount of acid, sulphatization and decomposition temperature, sulphatization and decomposition time, leaching temperature and time, solid/liquid ratio, and the effect of water addition during pugging were optimized. Under the optimized conditions (sulphuric acid: 25 wt % of ore / moisture: 20 wt % of ore / sulphatization temperature: 450oC / sulphatization time: 30 minutes / decomposition temperature: 700oC / decomposition time: 60 minutes / leaching temperature: 70oC / leaching time: 30 minutes and solid-liquid ratio: 1/4 by weight), Co and Ni extractions were found 91.4 and 84.4 percent, respectively. A pregnant solution containing 3.084 g/L Ni and 0.185 g/L Co was obtained. These results were considered sufficient for the leaching of lateritic nickel ores.

In this thesis, coal-water mixtures (CWM) with &Ccedil / ayirhan lignite were prepared to optimize the parameters of CWM having an ideal behavior which means that at maximum coal loading, relatively stable at static and dynamic conditions and exhibit low viscosity. For this purpose, the effect of the parameters such as pulp density, amount of chemical agents, particle size distribution, addition of methanol and pulp pH were investigated. Results showed that increasing pulp density negatively affects viscosity and allowable maximum pulp density was obtained as 60% when the particle size distribution has a d50 value of 22.82 &micro / m. The optimum amount of chemical agent was found as 0.9%, having 10% Na-CMC (Sodium Carboxymethyl Cellulose) and 90% PSS (Polystyrene Sulfonate). Minimum viscosity was achieved when the pulp pH was in natural conditions (pH=6.85). Addition of methyl alcohol increased the viscosity of CWM.

Dilution and ore recovery/loss have an important role in calculation of mineral reserves. Each percent increase in dilution and decrease in recovery negatively affects economic value of the reserve. These parameters are mainly controlled by the quality of the mine design and stoping practice. This study provides an approach developed for dilution and recovery/ore loss calculations. The contribution of mine design software (MineSight) and the recent survey technique called Cavity Monitoring System (CMS) were presented in this study. The purpose was to compare the new approach with the old system where the calculations had been done according to some assumptions and to optimize mineral reserve estimation process. Results indicate that the new approach used in reserve estimation process gives ~1.6% closer tonnages to the actual numbers and the grades are both ~1.6% closer to the actual values numbers when compared with the old system.

In this study it was aimed to analyse refining processes such as decreasing reducible oxide content of ladle slag with affecting parameters in low carbon aluminum killed grades and for the research Erdemir low carbon steel grades 7112K and 7110K are selected. There was a negative correlation between reducible oxide amount in ladle slag and desulphurization capacity of ladle slag with metal-slag reaction and steel internal cleanliness. To refine these properties of slag, aluminium dross, which was aluminium production discard and has a metallic content around %30-35 was used and after ladle treatment operation, decrease in reducible oxides such as FetO, MnO, SiO2, P2O5 was analysed. After the study it was observed that 653 kg. of converter slag leaked during tapping of steel and SiO2 ve P2O5 content of ladle slag had negligible change after ladle treatment. According to the results, it is observed that initial %10-12 (FetO + MnO) content was reduced to % 4.5-5.0 (FetO + MnO) after ladle treatment with use of aluminium dross. Beside of this, in order to see the effect of this slag reduction on steel cleanliness, low carbon aluminium killed grades were compared with ultra-low carbon aluminium killed grades having (FetO + MnO) content of %16-17 in slag. It was seen that reoxidation of aluminium (loss of dissolved aluminium) during continuous casting for ULC (ultra-low carbon) gradesis 144 ppm but for LC grades it was 94 ppm and it was being expected that ULC steel group would have higher inclusion content after casting.

In drilling technologies, Na-bentonite-water mixtures are used as drilling mud. As the reserves of sodium-bentonite decline, calcium or low-quality bentonites are activated with inorganic salts and/or treated with different types of polymers as an alternative to Na-bentonite. The quality of such bentonites, commonly referred to as extended bentonite may deteriorate under severe drilling conditions, such as / bacterial activity, high temperature etc. It was considered that borates could prevent the deterioration of extended bentonites due to their well known bactericide properties. This study involves the use of Na-Borate as an activating agent for bentonites in place of the commonly used Na-carbonate. The effects of Na-borate on the rheological and filtrate behaviours of two different bentonites, namely, Edirne Bentonite (E-Ben) and &Ccedil / ankiri Bentonite (C-Ben) were investigated. The results were evaluated based on API standards and in comparison to those of Na-carbonate activated bentonites. It was found that Na-borate could be used as a bentonite activator, although somewhat higher dosages (3,78% Na2O equivalent for E-Ben and 0,76% Na2O equivalent for C-Ben) than Na-carbonate (2,90% Na2O equivalent for E-Ben and 0,58% Na2O equivalent for C-Ben) are necessary to obtain the same rheological properties. In terms of aging, it was determined that aging had no adverse effect on v the rheological and filtrate properties of bentonite treated with carboxymethyl cellulose (CMC) and polyanionic cellulose (PAC), but rheological properties of bentonites treated with xanthan gum were found to deteriorate upon aging. The presence of Na-borate in the mud appears to alleviate this adverse effect.

Trona ore located in Beypazari is extracted by solution mining method with well pair connected by directional drilling technology. This thesis covers the determination of the dimensions of the initial (vertical) caverns formed in underground by use of a computer modeling (trademark: WinUbro/Poland) on the basis of horizontal and vertical leaching rates. The leaching rates were determined using the trona core samples from the ore deposit. The effect of insoluble content and the thickness of trona layer and solvent temperature on the initial cavern dimension were studied. The outcome of this study showed that the better the trona layer quality from the point of view of thickness and insoluble content, the wider the vertical cavern size is. In 1 m thick trona layer with 20% insolubles, it is possible to develop caverns of 6 m width, which is the minimum size for well pair connection. On the other hand, it is determined that the effective leaching time depends mainly on solvent temperature.