Turkish Coal Enterprises Research Articles

Lutetian–Bartonian (Middle Eocene) micropalaeontology, biostratigraphy and palaeoecology of the Mengen Coal Basin, Northwest Türkiye (Turkey)

This study focuses on the upper Lutetian–lower Bartonian Tokmaklar Formation in the Mengen Basin of Northwest Türkiye (Turkey), examining various aspects such as biostratigraphy, palaeoecology, and isotope data (δ18O and δ13C), providing insights into the geological history and environmental conditions during this interval. Moreover, the study incorporates coal petrography on four samples to explore a potential correlation between the coalification process and the preservation of palynomorphs. The formation is informally divided into two distinct categories: a coal-bearing sequence positioned at the base of the formation and a coal-free sequence above it. However due to dense vegetation and soil cover in the area, the availability of suitable outcrops for measured sections and obtaining samples is severely limited. Therefore, we relied on drilling data from Turkish Coal Enterprises (TCE) for the purpose of coal exploration, as well as two partial sections (Ender and Çorak) from underground mining. Microapalaeontological evidences involving benthic foraminiferans, ostracods, and palynomorphs, along with isotope data (δ18O and δ13C), suggest that the Tokmaklar Formation was deposited as a result of a local transgressive process during the late Lutetian–early Bartonian. Furthermore, palynological data, particularly the existence of mangroves such as Nypa, lepidocaryoid palm and Acrostichum aureum, coupled with quantitative palaeoclimate analysis, the negative δ18O values, and the lower δ13C values indicate a warm, probably tropical climate under high rainfall.

Evaluation and Comparison of Rock Bolting Versus Steel Arch Support Systems in Thick Coal Seam Underground Galleries: A Case Study

This study investigates the feasibility of rock bolting support in an underground coal mine gallery with a thick coal seam. The Ömerler underground coal mine working area, owned by the West Lignite Enterprise (GLI) of the Turkish Coal Enterprises (TKI), was selected for this purpose. Longwall top coal caving (LTCC) is implemented as the production method in the Ömerler underground coal mine. Field and laboratory studies were conducted to determine rock mass and rock material properties, followed by experimental, empirical, and numerical analyses based on the acquired data. The obtained design results were evaluated using a resin-grouted rebar (RBR) rock bolting system and steel arch support (SAS) pilot application areas. The numerical modeling results conducted using the Fast Lagrangian Analysis of Continua 3D (FLAC 3D) (v6.0) program indicated less displacement and secondary stress change in the RBR-supported zone compared to the SAS-supported zone. In situ measurements also demonstrated that RBR provided more successful support to the roof during coal production activities. The findings suggest that RBR is a more effective solution when evaluating the feasibility of rock bolting support systems in underground galleries with thick coal seams at the Ömerler underground coal mine. This study emphasizes the importance of more sustainable and safe support systems to enhance operational efficiency in the coal mining industry.

Upgrading low-rank lignite coals (Çan, Çanakkale/Turkey) by leaching

ABSTRACT Reserve of quality coal mines has been getting decreased all over the world, as well as Turkey. Presently, there is a concentrated effort in academia conducting intensive studies aimed at enhancing the quality of low-rank coals for utilization. Turkish lignite, containing high sulfur and ash, can be treated to remove sulfur and ash from the coal using physical, chemical, and biological methods. In this study, chemical (humic acid) and biological (Pseudomonas putida) leaching methods were applied for removing of pyritic and organic sulfur from a high sulfur content lignite coal taken from Çan (Turkish Coal Enterprises (TKI), Çanakkale, Turkey) region. The experimental study consisted of the two main stages as (i) column chemical leaching and bioleaching, and (ii) a combination of chemical and biological process at atmospheric pressure on physically the treated/cleaned lignite coal by heavy media separation. A clean coal product with 4.40% ash and 2.09% S content was obtained by both using chemical and biological leaching to the lignite coal treated/washed (16.46% ash and 6.14% S).

DETERMINATION BY NUMERICAL MODELING OF STRESS-STRAIN VARIATIONS RESULTING FROM GALLERY CROSS-SECTION CHANGES IN A LONGWALL TOP COAL CAVING PANEL

As a major pillar of global energy production, coal mining requires continuous advancements in efficiency to contribute to the broader goal of energy sustainability, all the while the shift towards more sustainable energy sources is underway. Mechanized excavation systems employed in underground coal mines, particularly within the longwall mining method, enable high-tonnage coal production. The Longwall Top Coal Caving (LTCC) method, one of the longwall mining techniques, has been developed for the effective extraction of coal from thick coal seams. However, as mining operations delve deeper, various complex issues, such as gallery cross-sectional variation, emerge. Gallery cross-sectional variation can increase the risk of collapse by affecting the stress distribution in the rock mass, posing a threat to worker safety. This study centers on the numerical modeling and analysis of gallery cross-sectional variation in the Ömerler underground mine, operated by the Turkish Coal Enterprises (TKI), West Lignite Enterprise (GLI). To achieve this objective, an extensive database was established through field and laboratory rock mechanics studies. This database was then utilized in the Fast Lagrangian Analysis of Continua 3D (FLAC3D) (v6.0) program to simulate the cross-sectional variations of the A6 panel in the Ömerler underground mine. The numerical simulation results provide valuable insights into the secondary stress-deformation changes associated with gallery cross-sectional variation.

Risk assessment of occupational groups working in open pit mining: Analytic Hierarchy Process

In open pit mining it is possible to prevent industrial accidents and the results of industrial accidents such as deaths, physical disabilities and financial loss by implementing risk analyses in advance. If the probabilities of different occupational groups encountering various hazards are determined, workers’ risk of having industrial accidents and catching occupational illnesses can be controlled. In this sense, the aim of this study was to assess the industrial accidents which occurred during open pit coal production in the Turkish Coal Enterprises (TCE) Garp Lignite unit between 2005 and 2010 and to analyze the risks using the Analytic Hierarchy Process (AHP). The analyses conducted with AHP revealed that the greatest risk in open pit mining is landslides, the most risky occupational group is unskilled labourers and the most common hazards are caused by landslides and transportation/hand tools/falling.

Upgrading low-rank coals (Çan, Çanakkale/Turkey) by float-sink separation in dense media

ABSTRACTTurkey coal reserves are mainly lignite (brown coal) and the majority of these reserves contain high-ash/sulfur coals, therefore, it is important to evaluate these low-quality lignite coals. Most of the produced lignite is utilized at the coal power stations in Turkey. The polluting gases containing sulfur dioxide after burning of low-quality coals are the main reason for air pollution, acid rain, and some respiratory systems diseases. In order to avoid these problems, high ash and sulfur-containing coal in our country need to be improved. In this study, the sink-float tests (heavy media separation) were applied to increase the quality of coal samples so that the ash and the impurities could be removed using a high ash-sulfur content coal sample (36.96% ash, 6.94% S and calorific value 3185 kcal.kg−1) taken from TKI (Turkish Coal Enterprises) Çan (Çanakkale, Turkey) lignite coalfield. The results of the float-sink tests showed that the most convenient washing operating density was 1.6 g/cm3, and the weight yield of the clean coal was 53.16%wt. (70.94% coal recovery) with 16.46% ash, 6.14% S with calorific value 5000 kcal.kg−1 using 10–0.5 mm size fraction of the coal.

Risk assessment of occupational groups working in open pit mining: Analytic Hierarchy Process

Abstract In open pit mining it is possible to prevent industrial accidents and the results of industrial accidents such as deaths, physical disabilities and financial loss by implementing risk analyses in advance. If the probabilities of different occupational groups encountering various hazards are determined, workers’ risk of having industrial accidents and catching occupational illnesses can be controlled. In this sense, the aim of this study was to assess the industrial accidents which occurred during open pit coal production in the Turkish Coal Enterprises (TCE) Garp Lignite unit between 2005 and 2010 and to analyze the risks using the Analytic Hierarchy Process (AHP). The analyses conducted with AHP revealed that the greatest risk in open pit mining is landslides, the most risky occupational group is unskilled labourers and the most common hazards are caused by landslides and transportation/hand tools/falling.

Forecasting the coal production: Hubbert curve application on Turkey's lignite fields

The dependence on imported energy sources is one of the biggest challenges that Turkey and many other similar countries face in the 21st Century and the gap between production and consumption cannot be decreased without increasing the domestic production. Forecasting of domestic energy production therefore plays a vital role in order to be able to develop sound energy policies towards maintaining sustainable development. However, although this question is essential in this respect especially for import dependent countries, the previous literature is surprisingly scarce. This paper, therefore, will be important for future studies on estimation of energy production. We first analyzed lignite production of Turkish Coal Enterprises (TKI) from a historical perspective and then forecasted the future production by using the Hubbert curve, depletion rate, and decline curve methodologies. We concluded that the largest fields are about to enter a declining phase of production in upcoming years and most of the reserves will remain untapped if business-as-usual continues in the future. The methodology and interpretations may be used by other developing countries, which deeply suffer from energy import dependency.

Equipment Selection by using Fuzzy TOPSIS Method

In this study, Fuzzy TOPSIS method was performed for the selection of open pit truck and the optimal solution of the problem was investigated. Data from Turkish Coal Enterprises was used in the application of the method. This paper explains the Fuzzy TOPSIS approaches with group decision-making application in an open pit coal mine in Turkey. An algorithm of the multi-person multi-criteria decision making with fuzzy set approach was applied an equipment selection problem. It was found that Fuzzy TOPSIS with a group decision making is a method that may help decision-makers in solving different decision-making problems in mining.

Analyses of non-fatal accidents in an opencast mine by logistic regression model – a case study

Accidents cause major damage for both workers and enterprises in the mining industry. To reduce the number of occupational accidents, these incidents should be properly registered and carefully analysed. This study efficiently examines the Aegean Lignite Enterprise (ELI) of Turkish Coal Enterprises (TKI) in Soma between 2006 and 2011, and opencast coal mine occupational accident records were used for statistical analyses. A total of 231 occupational accidents were analysed for this study. The accident records were categorized into seven groups: area, reason, occupation, part of body, age, shift hour and lost days. The SPSS package program was used in this study for logistic regression analyses, which predicted the probability of accidents resulting in greater or less than 3 lost workdays for non-fatal injuries. Social facilities-area of surface installations, workshops and opencast mining areas are the areas with the highest probability for accidents with greater than 3 lost workdays for non-fatal injuries, while the reasons with the highest probability for these types of accidents are transporting and manual handling. Additionally, the model was tested for such reported accidents that occurred in 2012 for the ELI in Soma and estimated the probability of exposure to accidents with lost workdays correctly by 70%.

An assessment of mining efficiency in Turkish lignite industry

This article focuses on the mining activities of Turkish Coal Enterprises (TKI), the major lignite supplier in Turkey. First, we analyzed the lignite production and overburden removal activities of TKI from a historical perspective and then employed the Principle Component Analysis to build a mining efficiency index of TKI and investigated its historical development since the establishment of the company. We found that labor productivity and operational structure have been the most important factors, positively affecting the index. The current article makes two important contributions: (1) by using the most comprehensive data set available on TKI for the first time, and (2) by developing a Mining Efficiency Index (MEI), which can be used to analyze productivity in lignite mining activities in different countries.

The analysis of total factor efficiency in the public lignite mining organisations in Turkey

Intense competition in today's globalised system requires the countries' resources to be produced and utilised in the most economic manner, which is only possible through efficient introduction of these resources by the business units. In this study, the efficiencies of the eight establishments of the Turkish coal enterprises (TKI) are analysed between the years 2006 and 2009 by using data envelopment analysis (DEA) and super efficiency (SE) methodologies. For the analyses, two output oriented models are constructed and used, namely production efficiency and revenue efficiency models. As part of the analyses, first the production and revenue efficiencies of the establishments were analysed using constant return to scale (CRS) and variable return to scale (VRS) methodologies of DEA. Next, the efficiency rankings of the efficient establishments were determined among themselves by using SE methodology. Finally, the calculated efficiencies are assessed and recommendations are provided for each TKI establishment. [Received: January 28, 2014; Accepted: August 15, 2014]

Efficiency Measurement in Turkish Coal Enterprises Using Data Envelopment Analysis and Data Mining

Gradual population growths, skyrocketing technological developments and inter-State competitions increase the energy demands continuously. Although the countries try to diverse their energy sources in order to sustain their developments, they also have to pay attention to protect their energy independences. Thus, it is very important to develop their self-resources. Coal is the most common natural source which can meet our energy needs. However, coal mine enterprises have to be administrated cost-effectively in order get minimum energy costs. In this study, the efficiency of Turkish coal enterprises between the years 2003-2010 is measured by using Data Envelopment Analysis (DEA). Then, indicators which are the most important in estimating the efficiency were determined by using the efficiency scores obtained by DEA in the Data Mining technique.

Evaluation of occupational injuries with lost days among opencast coal mine workers through logistic regression models

Despite precautions, mining remains the most hazardous occupation, and coal mining is one of the most dangerous industries for non-fatal occupational accidents. Accidents are complicated events with many factors that affect their formation, and statistical evaluation of accident records can produce valuable information that may prevent such accidents. In this study, a logistic regression analysis method was applied to non-fatal occupational injuries from 1996 to 2009 in an opencast coal mine for Western Lignite Corporation (WLC) of Turkish Coal Enterprises (TKI). The accident records were categorized as occupation, area, reason, age, part of body and lost days, and the SPSS package program was used for statistical analyses. Logistic regression analyses were used to predict the probability of accidents that resulted in greater or less than 3 lost workdays. It is found that the job group with the highest probability of exposure to accidents with greater than 3 lost workdays for non-fatal injuries was the maintenance personnel and workers. The employees were primarily exposed to accidents caused by a mining machine, and the lower and upper extremities have the highest probability of exposure to such risks. Finally, an equation for calculating the probability of exposure to accidents with greater or less than 3 lost workdays was derived. Then, the equation was used to determine the important accident risk factors.

Coal mining under difficult geological conditions: The Can lignite open pit (Canakkale, Turkey)

This paper describes the slope instability problems in the Can (Canakkale — northwestern Turkey) coal mine. Slope instabilities have been one of the major problems in the pit mine since the beginning of mining activities. In particular, the West and East Sector panels in front of the TKI (Turkish Coal Enterprises) buildings and the Seramic factory located in the vicinity of the pit mine have been suffering from slope instability problems. To assess the instabilities, field data collection from boreholes, surface sampling and monitoring studies were performed. Deterministic stability analyses such as limit equilibrium, sensitivity and back analyses were applied. Based on the results, the active–passive wedge type of failure was determined as the most dominant instability type. Based on the back analysis results, mean values of residual shear strength parameters were determined as c=42kPa, Ø=8°. The results also indicate that the excessive excavation of the toe along the huge lignite open pit was the main cause of the instability. The weak contacts between the lithological units were also an important factor. Taking into consideration the results of the analyses, some remedial measures were also suggested for the coal mine such as decreasing the inclination of the toe, safe benching and effective drainage of surface water and groundwater.

The Effects of Non-Controllable Factors in Efficiency Evaluation of Turkish Coal Enterprises

In this study, which aims to examine the effects of non-controllable factors as well as input parameters on the efficiency performances of Turkish Coal Mine Enterprises, eight enterprises within Turkish Coal Enterprises (TCE) were examined. In order to keep the study as up-to-date as possible, data from the latest year (2005) was examined. For each enterprise, the outputs consisted of the amount of the production sold and the total income gained in the corresponding year; the controllable inputs consisted of investment expenditure, overburden stripping and number of staff; and non-controllable inputs consisted of total reserve and low heat values. In order to measure the effects of non-controllable inputs on enterprise efficiency, three-stage modified data envelopment analysis (DEA) model was employed. In the first stage, information concerning the efficiency of the enterprises was gained by using only the controllable inputs and outputs. In the second stage, the effects of non-controllable inputs on controllable inputs in inefficient enterprises were examined. Lastly in the third stage, the new efficiency values were calculated by means of DEA where controllable inputs and outputs modified according to non-controllable inputs were used. Considering the non-controllable inputs as a result of the analyses conducted with three-stage DEA model, it was determined that the average efficiency value of Turkish Coal Enterprises increased from 87.5% to 92.3%.

Evaluation and monitoring an on-going landslide in volcanic sediments – a case study for an open pit mine, Turkey: Part 1

TKI (Turkish Coal Enterprises) has been operating an open pit lignite mine since late 1970s in a town called Çan which is situated in the north-west of Turkey. There is a ceramic factory, which is one of the biggest in Europe as far as capacity is concerned, operating very close to the lignite open pit mine. In 1999, a catastrophic earthquake demolished not only the cities and towns located on the Northern Anatolian fault zone but also triggered a landslide on the ceramic factory site benches of the Çan lignite open pit. The susceptibility of artificial slopes to failure during earthquakes is a wellknown event. This paper summarises geological, geomorphological and hydrological surveys of the area and the work done to define the slip surface by means of inclinometer surveys. Geotechnical parameters collected from all local geological formations were used later in the slope stability analysis. Details of the studies undertaken since the beginning of the landslide are given in this paper.

04/02210 The spontaneous combustion characteristics of Turkish lignite and correlation of the self-heating process with the actual fire: Guyaguler, T. et al. CIM Bulletin, 2003, 96, (1070), 75–79

Fires due to self-heating of coal have been a real problem since the beginning of mining. In order to minimize the harmful effect of fires caused by spontaneous combustion (sponcom), the tendency of coal for sponcom should be analyzed in detail. This paper presents the results of such research, which had two objectives: firstly, to determine the spontaneous combustion characteristics of lignites of all underground (u/g) mines of Turkish Coal Enterprises (TKl) in the laboratory and secondly, to use these self-heating characteristics to predict the stage and progress of actual mine fires. Representative samples of 16 different lignite seams were prepared for tests in the laboratory. Crossing-point temperature and adiabatic oxidation methods were utilized to characterize the spontaneuos combustion risks. During the experiment, time and temperature were measured, and released gases were continously recorded. Sponcom results obtained by both methods were in close agreement with each other, and it was determined that Turkish lignites are susceptible to spontaneous combustion with medium to high risk. All the information obtained from the laboratory tests was utilized to predict the progress of an actual mine fire. Finally, a fairly good correlation was established between the spontaneous combustion test results and an actual mine fire caused by self-heating. Observations of CO emissions during an actual mine fire, which occurred in the Middle Anatolian Lignite mine, supported the suggested prediction method. This prediction method is currently being used in all TKl's u/g mines.

A rippability classification system for marls in lignite mines

This paper describes the development of a rippability classification system for marls in lignites mines based on direct ripping runs, specific energy concept and indirect rippability assessment methods. Extensive field and laboratory studies were undertaken in six different panels of Turkish Coal Enterprises and Sivas-Kangal Lignite mines. Rock mass descriptions were made, seismic P-wave velocities are measured at the field, direct cutting tests and rock material property determination tests were carried out in the laboratory. The proposed method includes rock parameters such as uniaxial compressive strength, seismic P-wave velocity, discontinuity spacing and Schmidt hammer hardness value. In the developed method, rock properties are graded separately and rippability classes of rocks are determined according to the final grade. Appropriate dozer types and their productions are also proposed. Hence, both main components of rippability, rock and equipment properties are satisfied in the proposed system.

A New Method for Determining the Depth of Cut Using Power Shovel Monitoring

The method based on the power shovel monitoring is described for determining the depth of cut and the value of power consumption depending on the rock strength and the dipper position in digging operation. The investigations into mining shovels operating at different open-pit mines of Turkish Coal Enterprises were carried out.