Coal deposits of Turkey: properties and importance on energy demand

Κατά τις τελευταίες δυο δεκαετίες η παραγωγή και η κατανάλωση ηλεκτρικής ενέργειας στην Τουρκία αυξήθηκε με γρήγορους ρυθμούς. Περίπου 80% της παραγόμενης ηλεκτρικής ενέργειας προέρχεται από συμβατικά καύσιμα, όπως εισαγόμενο φυσικό αέριο και πετρέλαιο, αλλά και εγχώριους γαιάνθρακες. Καθώς όμως η σύγχρονη ενεργειακή πολιτική προσανατολίζεται σε μείωση της εξάρτησης από εισαγωγές καυσίμων, ο εγχώριος γαιάνθρακας, ιδιαίτερα ο χαμηλού βαθμού ενανθράκωσης, αποκτά σημασία για τη χώρα. Οι τελευταίες έρευνες ανεβάζουν τα αποθέματα σε ~13 Gt, με τον λιγνίτη και τον υποβιτουμενιούχο γαιάνθρακα να κυριαρχούν. Κοιτάσματα γαιανθράκων, που σχηματίστηκαν κάτω από διάφορες συνθήκες και σε διάφορες γεωλογικές περιόδους, υπάρχουν σε όλη τη χώρα. Τα σημαντικότερα είναι Τριτογενούς ηλικίας, με αυτά του Νεογενούς να είναι τα καταλληλότερα για ηλεκτροπαραγωγή εξαιτίας των μεγάλων αποθεμάτων παρά την υψηλή τέφρα και τη χαμηλή θερμαντική ικανότητα. Με την εφαρμογή ορθολογικής εκμετάλλευσης και καταλλήλων μεθόδων εμπλουτισμού ο γαιάνθρακας θα διαδραματίσει στο μέλλον σημαντικό ρόλο στην ενεργειακή τροφοδοσία της Τουρκίας.In the last two decades electricity generation and consumption in Turkey was increasing steadily. Around 80% of the electricity generated is derived from fossil fuels such as imported natural gas and oil, and domestic coal. As the energy policy now is focusing on reducing the dependency on imported fuels, coal, particularly this of low-rank, is becoming important for the country. Latest explorations showed that total coal reserves of Turkey reach to 13 Gt with low-rank coals (i.e. lignite and sub-bituminous) being dominant. Coal deposits, formed under various conditions and in various geological times, are widely spread over the territory. The most significant deposits are of Tertiary, especially Neogene age. Neogene coals are most appropriate for combustion in the thermal power plants due to the high total reserves despite the high ash yields and the low calorific values. We imply that applying reasonable exploitation planning and appropriate washing techniques, coal will play a key role in future energy supply of the country

COMBUSTION AND LEACHING BEHAVIOR OF TRACE ELEMENTS IN LIGNITE AND COMBUSTION BY-PRODUCTS FROM THE MUĞLA BASIN, SW TURKEY

The Muğla Basin is one of the most well-documented coal basins of Anatolia, SW Turkey. Previous studies mainly focused on coal geology, as well as on the environmental impacts from trace elements emitted into the atmosphere during coal combustion. However, the environmental impacts from coal utilization also include groundwater contamination from hazardous trace elements leached from exposed lignite stockpiles or ash disposal dumps. In the present study a comparative assessment of the combustion, as well as the leaching behaviour of trace elements from sixteen lignite, fly ash and bottom ash samples under various pH conditions is attempted. The samples were picked up from three regions in the Muğla Basin, namely, these of Yeniköy, Kemerköy and Yatağan. Proximate and ultimate analyses were performed on all samples. Quantitative mineralogical analysis was carried out using a Rietveld-based full pattern fitting technique. The elements Ag, As, B, Ba, Be, Co, Cr, Cu, Fe, Ga, Hf, Li, Mn, Mo, Ni, Pb, Sr, U, V and Zn were grouped according to their volatility during combustion and their leachability in the various types of samples. The pH of the leaching agent little affected the leaching trends of most elements and the mode of occurrence proved to be the major factor controlling primarily combustion and to a lesser extent leaching. The elements were classified into 7 classes with increasing environmental significance with Mo, Sr and V being the most potentially hazardous trace elements in the Muğla region

Turkish lignite deposits

The distribution of lignite deposits in Turkey is such that in general the Eocene lignites are in northern Turkey, Oligocene lignites are in northwestern Turkey, Miocene lignites are in western Turkey, and Pliocene-Pleistocene lignites are in eastern Turkey. Only the Oligocene lignites are paralic deposits, the rest being formed in a limnic environment. Turkey has about 8.4 Gt of lignite reserves of which 3.9 Gt are the exploitable reserves. Most of the known lignite deposits in Turkey are of low calorific value and have high contents of ash, moisture and total sulphur. Almost 80% of the total reserves have calorific values below 2500 kcal kg-1. The lignites having low calorific values are generally consumed in power plants. The lignites having relatively high calorific values are exploited for domestic and industrial use in the country. The majority of Turkish lignite deposits are worked in open-pit mines, but there are also some underground operations

Economic evaluation of Bursa-Orhaneli Lignite coalfield

Bursa-Orhaneli lignite coalfield is located in the North-West of Turkey. This coalfield has three sectors: Burmu, Çivili, and Sagirlar, having similar stratigraphic sequences in the northwest of Bursa Province. The mined coal seam is Miocene of age, and its thickness varies between 1.10-14.50 m. The pre-Neogene rocks in the area are made up of Palaeozoic aged metamorphic schists and marbles, and Upper Cretaceous aged ophiolites. The Neogene formations of detrital rocks with basal conglomerates, coal bearing marl and tuffites are found at the base, and volcanic basalt tuffs and andesite lava flows, at the top. The post-Neogene sediments are Pleistocene aged gravels and Holocene alluvium.The deposit has been worked as an open-pit mine in the Burmu and Sagirlar sectors and is going to be worked by underground mining methods in the near future. The chemical analysis have shown that the percentage of water is 22.66-27.30%, ash 24.57-44.39%, volatile matter 18.52-29.44%, fixed carbon 23.87-29.52%, and total sulphur 1.84-2.64% in the original coal, and its calorific value is 2010-3032 kcal/kg, whereas the air dried coal is composed of 5.51-10.41% water, 26.99-54.18% ash, 21.83-35.49% volatile matter, 28.10-36.03% fixed carbon, and 2.42-3.06% total sulphur, with calorific value of 2483-3938 kcal/kg. The proven and workable lignite reserves are 60,877,079 and 47,308,406 tonnes respectively. Stripping and production operations are made by a dragline, excavators and trucks. Mined coal is used both in domestic heating and the Orhaneli thermic power plant, which has a capacity of 1x210 MW

Valorisation of the Geological Values (Future Geosite Candidates) Around the UNESCO World Heritage Asset of Hittite Capital Ḫattuša, Türkiye

The ancient city of Ḫattuša, which is already in the UNESCO World Heritage List, is one of the most attractive cultural tourism spots in the central Anatolian landmass. The city is located in the Boğazkale district of the Çorum province and is one of the most important settlements in the Hittite history. The city had served as the capital of the Hittites approximately for 500&nbsp;years. The oldest archaeological findings in this ancient city start from the Chalcolithic Age and extend to the Byzantine period; however, the city reached its golden ages during the reign of the Hittite Empire. Especially the construction of the monumental structures has been considered to be initiated during the old Hittite Kingdom, in the mid-sixteenth century B.C. Besides the famous cultural tourism attractions, the city and its surroundings host important geological structures. In this aspect, we propose twelve potential geosite candidates, which are quantitatively evaluated. These potential geosites are evaluated in basis of their stratigraphic, volcanic, sedimentological, structural geological value and historical significance. Especially, six of these geosite candidates are already located within the archaeological protection area and have an important potential to be registered as future geosites. A quantitative assessment of these geosites and the region for its scientific value (SV), potential educational use (PEU), potential touristic use (PTU) and degradation risk (DR) has shown that the study area has moderate high regional SV, PEU and PTU scores (288, 279 and 278, respectively) and low moderate (213) DR score. The results of the quantitative assessment show that the region has an important potential for geology education and geotourism activities.</p

Depositional features and coal potential of the Gölbaşı- Bahçeköy Neogene Basin, Ankara (Central Turkey)

The Bahçeköy coal field, which is the subject of this study, is located in the Gölbaşı Neogene basin in the south of Ankara (central Turkey). The pre-Neogene basement rocks located in the west and south of the basin are mostly composed of Permo-Triassic carbonate rocks, Cretaceous ophiolites, and Eocene turbidites. The coals in the Bahçeköy area are observed in the lower part of the Pliocene lacustrine sedimentary sequence which fills the basin. In the western part of the basin, the basalts and the lacustrine sediments, which contain coal, show intrusive contact relations in the lateral direction, during the Pliocene period, with the effect of the volcanism developing at the same time with sedimentation. Diatomite intercalations were formed at the upper parts of the lacustrine sequence which reached 12 m. The widespread observation of diatomites is quite important and it implies that the silicon-rich solutions associated with volcanism are involved in the lacustrine environment. The thickness of the economic coal level in Bahçeköy area varies between 4 and 12 m. According to these thicknesses, the total coal reserves calculated for the Bahçeköy area reach up to 16 million tons. The obtained drilling data shows that Bahçeköy coals exhibit rapid thickness and quality changes in the lateral direction. The chemical analyses point out these coals have average calorific value ranging from 7762 to 12,413 kJ/kg and ash content ranging from 44 to 65%. © 2019, Saudi Society for Geosciences