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Properties of lignite from the Konya-Ilgin-avu u deposit and its potential usein a future power plant (Turkey)

Hulya Inaner

Dokuz Eyll University, Faculty of Engineering, Department of Geology, 35100 Bornova Izmir, Turkey.E-mail: hulya.inaner@deu.edu.tr

Ab st ra ct . The Konya-Ilgin-avu u lignite coalfieldis located in thecentral part of Turkey. This coalfieldhas been mined in an open-pitmanner by pri-vate companies. Thereis a singlemined coal seam, thethickness of which variesbetween1.10-37.15m. A total of sixty five boreholes have been drilled inthe area toward assessing the reserves. Confirmed and extractable reserves have been calculated by the polygon and isopach methods, depending on theboreholes drilled at different times. There is enough coal in the Ilgin-avu u coalfield to fuel a thermal power plant.

Key words: lignite, coalfield,Turkey

Introduction

Turkey currently has about 8.4 Gt. of lignite reserves, of which 3.9 Gt. are ex-ploitable. Most of the known lignite de-posits in Turkey have low calorific va-lues and high ash, moisture, and totalsulphur contents. Almost 80% of the to-tal reserves have calorific values below10.46 MJ . kg1. The lignites having ca-lorific values lower than 10.46 MJ . kg1

are generally consumed in power plants,while those having calorific values higherthan 10.46 MJ . kg1 are directed towardshousehold and industrial uses. The majo-rity of Turkish lignite deposits are wor-ked as open-pit mines, though there arealso some underground operations.

Miocene, Pliocene, and Quaternarycoals are formed in limnic and limnicfluvial environments with somevolcanogenic intercalations. The totalextent of the coal-bearing Miocene(835.1 km2) and Pliocene (526.9 km2)deposits is 1,362 km2 (Tuncali et al.2002).

The lignite potential of the Konya re-gion, whose coals have low calorific val-ues and high moisture contents, can con-tribute to Turkeys energy requirements(Fig. 1). While the total confirmed lig-nite reserve is 447,924,615 tonnes,the total mineable reserve is 350,857,868tonnes, while the total probable reserveis 80,763,455 tonnes (Inaner and Nako-man 1997).

Explorationstudies have been performed by theAkpinarMadencilik Company in this area (Akpinar Madencilik

1988). Sixty five boreholes were drilled in this coalfield to-ward assessing the reserves.

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Figure 1. Location map of Konya region coalfields.

Bulletin of Geosciences, Vol. 80, No. 1, 1922, 2005 Czech Geological Survey, ISSN 1214-1119

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Dokuz Eyll University made a feasibility study in1989 for the Akpinar Madencilik Company (Nakoman etal.1989).Karayigit et al. (1999) determined thegeological,geochemical, and palynological properties of the Ilgin arealignite deposits in the Konya province. A graduate-studyproject was undertaken by Ilter (2000) under the supervi-sion of the present author.

Geology

The Konya-Ilgin-avu u lignite coalfield is located in thecentral part of Turkey (Fig. 2). This coal field has beenworked as an open-pit mine by private companies in thenorth-western part of the Konya Province. The mined coalseam is of the Pliocene age (Gkmen et al. 1993) and itsthickness varies between 1.7037.35 m. The pre-Neogenerocks are made up of Paleozoic metamorphic schists andmarbles, and Mesozoic crystalline limestones (Figs 3, 4).Coal-bearing sediments lie unconformably on the crystal-line metamorphic substratum. The Pliocene coal-bearingunits are made up of basal conglomerate, gravelly clay,sandstone, coal seam, marl, limestone, red coloured gravel,sand, clay, and mill. All units were covered by alluvium(Gkmen et al. 1993). Lignite generally appears as a single

seam and is generally quite thick. Intercalations are rare.The basin is limnic, not paralic.

Economic evaluations

A total of sixty five reserve boreholes have been drilled inthis coal field. Among these boreholes only forty five cutmineable coal thickness and were used in our calculations.Confirmed and mineable reserves were calculated by poly-gon and isopach methods, depending on the boreholes dril-led in different years.

Theconfirmedreserves were calculated as 163,968,634tonnes by using the isopach method with a 1 : 5000 scalemap (Ilter 2000).

Suppositions for reserve calculations

For the reserve calculations 1 : 5000 scale maps were used.The borehole location map from the Akpinar Madencilik Company wasused to determine thecoal depositsbounda-ries, and our calculations for reserve determinations are ba-sedon theborehole valuesobtained by theAkpinar Maden-cilik Company.

The following suppositions were made in order to de-termine the exploitable coal thickness in the reserve calcu-lations: Coal formations having calorific values higher than

2.93 MJ . kg1

in the original coal were included in theexploitable main coal layer thickness.

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Figure 2. Location map of Konya-Ilgin-avuu lignite coalfield.

Hulya Inaner

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The sterile formations of clay, marl,etc. in the coal layer were included inthe coal seam if they were thinnerthan 0.50 m; if thicker, they were as-sumed as the interval thickness.

Coal layers which are not directly re-

lated to the main coal seam and existabove or below it, were included intothe main coal seam thickness if theywere thicker than 1.00 m. Coal layersthinner than 1.00 m were assumed tobe unexploitable.

Coal and interval densities were ta-ken as 1.3 and 1.8 ton . m3, respecti-vely.

Mining loss was assumed to be 10%,and the geological matching coeffici-ents were considered to be 1.000.70depending on the locations of poly-gons and faults.

Dilution was assumed to be 0.10 mfrom the top and bottom of the seam.

Existing analyses of the sterile layersthinner than 0.50 m have been takenas is. Where there are no analyticalresults, moisture was assumed to be25%, ash 75%, lower calorific value1 in the original coal, and moisture5%, ash 95%, lower calorific value 1in the dry coal in air.The total coal-bearing area is

8,931,876 m2

, excluding the area still be-ing mined today. The confirmed andworkable lignite reserves are168,379,425and 144,569,064 tonnes, respectively,calculated based on the polygon method.

An overburden of 1,585,426,669 cu-bic meters, an intercalation overburdenof 6,893,497 m3, and a total overburden1,592,320,167 are estimated in this coalfield. The average overburden ratio wasfound to be 11.01 ton . m3 for the wholecoal field by the polygon method.

The chemical analyses have shown the water content tobe 48.64%, and ash 20.30%, in the original coal, the calo-rific value of which is 8.24 MJ . kg1. The air dried coal iscomposed of 10.03% water and 30.82% ash, with a calo-rific value of 16.41 MJ . kg1.

Results

Mined coal is used for domestic heating and for industrialpurposes, especially by the sugar factories in the region.According to recent studies, the reserves in this coal fieldcould supply a thermal power plant with a capacity of

2 240 MW for more than forty years. Building the ther-mal power is expected to take about three and a half years,

with 25003000 workers expected to participate in its con-struction. Additionally, one thousand workers are to be em-ployed in mining the coal deposit. The power plant is plan-ned as a build-operate-transfer model to produce energyfor thirty eight years. When this project is finished, it willhave positive effects on the Ilgin area, as the power plantwill constitute an important contribution to Turkeysenergy production.

Refere nces

Akpinar Madencilik (1988): Annual Report (Unpublished). Konya.Ilter . (2000): Reserve estimation of Konya-Ilgin-avu ugl lignite

coalfield by polygon and isopach methods. Graduate thesis, DokuzEylul University, Izmir.

Inaner H., Nakoman E. (1997): Lignite Possibilities of Konya Region and

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Figure 3. Schematic stratigraphic section of the avu u coalfield.

Properties of lignite from the Konya-Ilgin-avu u deposit and its potential use in a future power plant (Turkey)

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its Importance for Turkey. Seluk University, Engineering and Ar-chitect Faculty, Geology Department, 20thGeology Symposium Ab-stracts, Konya, 2829.

Gkmen V., Memikoglu O., Dagli M., z D., Tuncali E. (1993): LigniteInventory of Turkey. Mineral Research and Exploration DirectoratePubl., Ankara.

Karayigit A. I., Akgn F., Gayer R. A., Temel A. (1999): Quality,palynology, and palaeoenvironmental interpretation of the Ilgin lig-

nite, Turkey. International Journal of Coal Geology 38, 219236.Nakoman E., Kse H., alapkulu F., Inaner H., ebi Y., Simsir F.,

Onargan T., Konak G., Kemal M., Ergin Z. (1989): Pre-feasibilitystudy of Konya-Ilgin-avu u lignite coalfield.Dokuz Eylul Univer-sity, Engineering and Architect Faculty, Izmir.

Tuncali E, Cifti B., Yavuz N., Toprak S., Kker A., Aik H., Gencer Z.,ahin N. (2002): Chemical and technological properties of Turkishcoals. Mineral Research and Exploration Directorate Publ., Ankara.

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Figure 4. Geological map of Konya-Ilgin coalfield area.

Hulya Inaner