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Öğe Determining the relations between mechanical and electrical characterization of rocks(2007) Bilim N.; Ozsen H.; Ozkan I.Determination of mechanical parameters of rock materials and using them as an input data-base are important in rock engineering design studies. The standard test procedures to determine mechanical parameters of rocks have been developed and they have been applied for up to 40 years. But these tests require special samples and after preparation, the samples are tested by giving damage to them. The electrical conductivity method has been used to determine porosity, fault or discontinuity in rock mass without giving damage, especially in underground gas, water or petroleum storage excavations or excavations opened for waste dumping studies. In this study, an alternative nondestructive measuring technique developed in order to predict mechanical properties of rocks was presented. The electrical conductivity and mechanical properties of rock materials were analyzed in order to research whether there are relationships between mechanical and electrical behaviors. Tests samples were prepared taking cores from eight different rock blocks. The tests in laboratory were carried out in two different stages: the first was electrical conductivity and the second was mechanical tests. Electrical potential difference (EPD) values of 30 samples were measured. In addition, the uniaxial compressive strength, indirect tensile strength, uniaxial deformability, point load strength, Schmidt hammer, density and porosity tests on 30 samples were carried out in laboratory. As a result, strong relationships were found between electrical conductivity and mechanical properties.Öğe The effect of shape and size for marble rock units under uniaxial compression(2007) Ozsen H.; Bilim N.; Ozkan I.The uniaxial compressive strength (UCS) of rocks is an important parameter used in rock mechanics studies. The standard test procedures in order to determine UCS value has been developed by ISRM and ASTM. According to these standards, the tests should be carried out on core samples but they say that the tests should be also being carried out on cube samples. There are a lot of papers published about the size effect of intact core samples. According to the articles and standards, the length (l) - diameter (d) ratio for core samples must be 2.5-3. Unfortunately, it was determined that the detailed studies about size effect for cube samples were not given in literature. To determine UCS values of marbles, cube samples sized 7 cm have been prepared by researches. But it was determined that the UCS values found by using dimensions suggested by ISRM and ASTM were different from each other for core and cube samples. In this study, the core and cube samples different in four marble units were prepared in the laboratory. While the l/d ratio for core samples is selected as 2.5-3, it was decided that the dimensions for cube samples were selected as 50, 70 and 100 mm. 20 core samples and 66 cube samples were tested under uniaxial compression by hydraulic press with servo control which has 3000 kN capacity. A data-base was formed by the uniaxial compressive strength and uniaxial deformability test results. Using the data base, the UCS values of the core and cube samples were compared by graphs. As a result, size and shape effect on uniaxial compression of marbles were discussed and their interpretations were presented in this paper.Öğe General assessment and estimations of occupational accidents and disasters in Turkey Coal Mines(International Pittsburgh Coal Conference, 2014) Bilim N.; Kekeç B.; Dündar S.Mining sector is very important for all county economy and employment. However, this sector has very risks in respect to occupational safety and health. Coal mining has the most risk in all of the mining sector. Hence in this sector with most work accidents and occupational diseases are encountered in an intensive. Coal mining is a relatively dangerous industry. Employees in coal mining are more likely to be killed or to incur a non-fatal injury or illness, and their injuries are more likely to be severe than workers in others industry. Work accidents are the big issued in mining industry of Turkey, because it can be significant influences to mining operations or activities. The coal mining industry plays an important role contributing to the national economy and development in Turkey, otherwise the mine accidents are become a big issues or problems. Sectorial examinations in 2013, the mining and quarrying sector is the maximum work-related accidents (10.4%) as the sector emerges. Safety in coal mining in Turkey is a critical issue. The number of fatalities is unacceptably high. This paper presents statistical analysis of Turkey coal mine accidents in last decades and analyzes the reasons causing coal mining high risk from technical and others viewpoints. Also, we explained occupational health and safety in relation to improve safety performances or accidents prevention.Öğe The importance and state of coal industry in Turkey's energy policy(International Pittsburgh Coal Conference, 2014) Kekeç B.; Bilim N.Coal which has widely reserve in the world has important position in energy raw materials and it has widely consumption area. Nowadays, the most important requirement of developed and developing countries is energy. Energy is a significant factor for economic development and social prosperity of countries. In this study, Turkey's energy situation, distrubition of primer energy generation and consumption based on source and importance of coal production in Turkey were emphasized in terms of energy generation.Öğe A model to predict the performance of drum shearers: An example from a Çayirhan lignite mine, Ankara, Central Turkey(2010) Bilim N.; Ozkan I.A model to predict the cutting performance of drum shearer machine from a Çayirhan lignite mine, Ankara, Central Turkey was developed. The mechanism of fracture showed the relationship between cuttability and physico-mechanical properties of the coal. Coal strength properties were known to affect the support capability of coal pillars and the cuttability and grindability of coal. In-situ experimental studies were conducted at the Çayirhan underground lignite mine situated in the Beypazari Basin. The total extraction with a retreating longwall method was used in the Çayirhan coal mine. The thickness of the coal seam at the location of the experiment was 1.5m, so the area planning of tests was 72m2. The main measurement area was chosen from the middle part of the longwall face where the roof stress was systematic. Schmidt hammer tests were used at two different locations of the longwall faces at a total of eight coal faces.Öğe Occupational health and safety outlook in Turkey(CRC Press/Balkema, 2015) Bilim N.; Bilim A.The safety and health conditions at work are very different between countries, economic sectors and social groups. Deaths and injuries take a particularly heavy toll in developing countries, where a large part of the population is engaged in hazardous activities. A healthy and safe work environment not only is desirable from the perspective of workers, but also contributes considerably to labour productivity and, as a consequence, promotes economic growth. Occupational accidents have been a significant problem in Turkey as it is all over the world. Occupational safety in in Turkey is a critical issue. The number of fatalities is unacceptably high. This study examines occupational accidents all over Turkey on a sectorial basis and also the change in accidents throughout the years. A sectorial and statistical assessment of occupational accidents in Turkey was conducted to examine the reasons for the high level of occupational accidents in the country. Also, explained occupational health and safety in relation to improve safety performances or accidents prevention. In the light of these statistical assessments, reasons and outcomes of occupational accidents in Turkey were assessed, and solution offers were given in order to decrease occupational accidents. This article presents the data in Turkey during a 13-year period (2001-2013). © 2015 Taylor & Francis Group, London.Öğe Reasons for occupational accidents in road-building construction sites(CRC Press/Balkema, 2015) Bilim A.; Bilim N.; Çelik O.N.Safety within road work zones has been an important issue and a major concern of engineers, government agencies, and the road construction industry. Road construction zone safety has been a research focus in many countries for many decades. For decades, the importance of road work zone safety has increased considerably with the continual increase in the number of road work zones present on road for repairs and expansion. Highway and road construction workers are at risk of fatal and serious nonfatal injury when working in the vicinity of passing motorists, construction vehicles, and equipment. For decreasing the occupational accidents, it is important to get to know and take precautions against the parameters causing occupational accidents experienced by workers working at road-building jobs. This study addresses the most frequent accident types in road-building construction sites and their reasons, and offers recommendations regarding the precautions to be taken to prevent such accidents. © 2015 Taylor & Francis Group, London.Öğe Stable crack propagation studies in marble and travertine(2007) Ozkan I.; Bilim N.; Ozsen H.The crack propagation researches carried out on rock and rock mass are important in mining, petroleum and natural gas engineering studies. It is assumed that crack propagation is an important design parameter in underground and open-pit mining applications. It has positive effects in some mining activities such as drilling, blasting, excavating, block caving but also negative effects due to cracks formed around mine roadways, tunnels and in landslides. In this research, the marble and travertine were selected as natural model materials. They have different texture, porosity, strength and natural water contents. Double cantilever beam specimens were prepared from blocks. These model samples were tested by hydraulic press which has 3000 kN capacity with 0.2 kN divided scale. The vertical and horizontal deformations formed on samples during crack propagation were measured by dial-gauge which has an accuracy of 0.01 mm. Stable crack propagation was observed by video camera. The crack propagation on samples was analyzed using data-base obtained from test results. As a result, the effect on the crack propagation of the texture, initial crack length and also fracture toughness depend on load were discussed and their interpretations were presented in this paper.
