Seam Modelling and Reserve Calculation for Lignite Field in Adana-Tufanbeyli (Turkey)

Abstract

Since the first investment in mining operations is very high, so, it is absolutely important to model the field in
three dimensions for appropriate planning and cost analysis. The whole data set belonging to the geological, geophysical
and drilling exploration studies carried out in the field should be evaluated as a package. In the modelling phase, the
computer-aided tri-dimensional mining software has been used instead of the classical reserve calculation methods being
utilized in previous years. Thus, more realistic and shorter results are achieved. In the present work, three-dimensional
seam modelling of the Adana-Tufanbeyli (Turkey) lignite field was carried out. In modelling, the coal horizon of the
field was examined. Then, the sub-seam levels in the horizon were determined and after examining their geometric
relationships with each other, three sub-seams were defined. Seam composites were prepared by the downhole method
to make the analysis results of different sizes uniform. It is possible to make block quality estimations, which will be the
basis for reserve calculations, by creating variograms in different directions. Variograms are first created in the vertical
direction and then in the horizontal direction respectively, to obtain the necessary parameters. The nugget effect and
structural distance parameters were obtained from the created variogram models. To assign quality estimation values on
the block model, the Kriging method was used when the number of data was sufficient, and the inverse distance method
was applied, when it was insufficient. As a result of this modelling study, a total of 355.617.194 tons of lignite reserves
with an average calorific value of 1.153 Kcal/kg were determined in the field.