Ahmet Dag

Development of a GIS-based information system for mining activities: Afsin-Elbistan lignite surface mine case study

In this study, it was aimed to monitor mining activities and product movements by establishing a mine information system and to give the optimum decision by conducting the necessary inquiries and analyses. For this purpose, at first the map materials used in the mining activities in Afsin-Elbistan lignite basin were converted to digital maps by means of GIS techniques, and after that the lignite deposit was modelled in 3D, by utilising drill holes data and geostatistical methods. With the integration of the table and graphical data obtained in this way in GIS environment, performance of location-dependent analysis, such as the determination of reserve-quality distributions, was made possible. Within this scope, it was demonstrated that the reserve quantities and statistical information of all attributes included in the databases selected from the screen or of any other databases generated through inquiries are accessible, and also thematic maps can be generated.

Mapping water chemical variables with spatially correlated errors

One of the most important considerations in many environmental studies is need to allow for correlations among the variables. Monitoring and analyzing relationships between chemical environmental parameters using spatial correlation based regression modelling is the main motivation of this applied study. For this purpose, some noticeable environmental parameters of data sets obtained from two lakes have been considered and the concentrations of chemical variables such as cadmium and nitrate have been appraised by a regression-based geostatistical methodology. The modelling procedure consists of two stages. In the first stage, spatial variables are analyzed via multi-linear regression and some relationships are provided. Next, by using the spatial auto-correlations of the residuals, a type of regression-based kriging procedure is applied. The capacity of the model for appraising the water chemical variables is also tested and performance comparisons with ordinary kriging are conducted. Finally, the applications showed that analyzing water chemical variables with spatially correlated errors is a convenient and applicable approach for assessing the environmental systems.

Investigation of the Effects of Marble Material Properties on the Surface Quality

This study aims to investigate the effects of material properties of marble on surface roughness and glossiness. For this purpose, four types of limestones were investigated. Physicomechanical properties of samples were determined through laboratory measurements. Mineralogical and petrographical characterizations were made using thin-section analysis. X-ray fluorescence (XRF) semiquantitative method was used for chemical analysis. Six different grinding-polishing tests for each marble unit were done under fixed operational conditions using the same abrasive series. Relationship between the material properties and the surface quality was investigated. Although the polishing-grinding tests were conducted under the same operational conditions, different levels of roughness and glossiness were observed on different samples. Data obtained from the study proved that the main cause of this difference is textural and chemical composition variations of the marble specimen. Moreover, statistical evaluations showed that porosity, uniaxial compressive strength, and indirect tensile strength have strong effects on the surface roughness and glossiness of the marble specimen. The presence of an inverse relationship between the glossiness and roughness levels was determined as the result of this study as well.

Geological modeling of a stratified deposit with CAD-Based solid model automation

The planning stages of mining activities require many comprehensive and detailed analyses. Determining the correct orebody model is the first stage and one of the most important. Three-dimensional solid modeling is one of the significant methods that can examine the position and shape of the ore deposit. Although there are many different types of mining software for determining a solid model, many users try to build geological models in the computer without knowing how these software packages work. As researchers on the subject, we wanted to answer the question “How would we do it”. For this purpose, a system was developed for generating solid models using data obtained from boreholes. Obtaining this model in an AutoCAD environment will be important for geologists and engineers. Developed programs were first tested with virtual borehole data belonging to a virtual deposit. Then the real borehole data of a cement raw material site were successfully applied. This article allows readers not only to see a clear example of the programming approach to layered deposits but also to produce more complicated software in this context. Our study serves as a window to understanding the geological modeling process.

A Computer Program for Practical Semivariogram Modeling and Ordinary Kriging: A Case Study of Porosity Distribution in an Oil Field

Abstract In this study, firstly, a practical and educational geostatistical program (JeoStat) was developed, and then example analysis of porosity parameter distribution, using oilfield data, was presented. With this program, two or three-dimensional variogram analysis can be performed by using normal, log-normal or indicator transformed data. In these analyses, JeoStat offers seven commonly used theoretical variogram models (Spherical, Gaussian, Exponential, Linear, Generalized Linear, Hole Effect and Paddington Mix) to the users. These theoretical models can be easily and quickly fitted to experimental models using a mouse. JeoStat uses ordinary kriging interpolation technique for computation of point or block estimate, and also uses cross-validation test techniques for validation of the fitted theoretical model. All the results obtained by the analysis as well as all the graphics such as histogram, variogram and kriging estimation maps can be saved to the hard drive, including digitised graphics and maps. As such, the numerical values of any point in the map can be monitored using a mouse and text boxes. This program is available to students, researchers, consultants and corporations of any size free of charge. The JeoStat software package and source codes available at: http://www.jeostat.com/JeoStat_2017.0.rar

Application of Response Surface Methodology and Central Composite Inscribed Design for Modeling and Optimization of Marble Surface Quality

Factors affecting the final surface quality of polished marble are not yet fully understood. Clarifying these factors for optimization of multivariate polishing process by trial and error method is difficult, time-consuming, and costly task. In this study, the empirical practices were carried out using an experimental design, specifically, a central composite inscribed (CCI) design. The factors considered in CCI design were belt speed, rotational speed, and pressure of the polishing head, and the responses were surface glossiness and roughness. Mathematical models describing responses were produced using experimental datasets, and analysis of variance (ANOVA) was used to assess the fit of the models generated with the experimental data. For process optimization, desirability function analysis (DFA) was used. This study has shown that the CCI could efficiently be applied for the modelling of polishing machine for surface quality of marble strips. Better surface quality generally resulted from lower belt speeds, which increased contact time between the abrasives and strips. Optimized surface quality for marble specimen was established.