COAL REOSURCES CLASSIFICATION USING VARIOGRAM TO DESCRIBE THE SPATIAL VARIABILITY

Sangatta coal field area is divided into two areas, the western and the eastern zone. Based on the qualitative analysis of geology, west zone is classified in moderate geological conditions and the eastern zone is classified in complex geological conditions. In this research, using the range of the variogram to calculate distances between drill holes spacing for resource classification. It can be unreliable when a variogram is constructed using few data points, and if there is a high proportion of nugget variance compared to total variance. The variogram may assist in defining distances of continuity between point if observation. There are three categories for classifying the coal resources, depending from the range distance of variogram, by which information points, West Sangatta are separated: Measured: Separated by 116 m of distance from each other. Indicated: Separated from 116.m to256.m of distance from each other. Inferred: Separated from266.m to 528 m of distance from each other. East Sangatta is separated: Measured: Separated by 55 m of distance from each other. Indicated: Separated from 55.m to 110.m of distance from each other. Inferred: Separated from 110.m to 244 m of distance from each other. This variogram has not been calculated across the multiple data. It just takes into account the coal seam thickness. For example, when the variogram is done for another variable, the results are different