Determination and modeling of lignite reserve using geostatistical analysis and GIS

Abstract

Thrace Basin is one of the most significant coalfields due to the lignite reservoir in Turkey. A coal deposit was chosen as the study area in the Thrace coal basin, which is tertiary within Oligocene geological formation. The purpose of this study is to produce modeling of coal seams in the study area and to create spatial distribution maps for estimation of lignite coal resource characteristics using geostatistical methods with Geographic Information System (GIS) technology. Spatial continuity of the coal depth data was forecasted with an empirical variogram. The performance of six different models has been compared for ordinary kriging separately for both skewed data and transformed data according to the presence and absence of the trend. Spatial structure of the coal depth data was better explained using circular models. The nugget-sill ratio was indicated high spatial dependency with 0.002 and 0.009 for upper-lower surfaces of coal seams respectively. The estimations obtained for coal depth data were represented in a map. In the study area modeled with ordinary kriging method, it was estimated that there was a 17,516,997 m3 coal reserve as a result of the reserve calculation made with ArcGIS 10 software.