Perpustakaan Digital ITB

Drilling pattern and spacing can be correlated to the spatial heterogeneity of coal properties. The optimumdrilling pattern and spacing is directly associated to the number of drillhole and budget reguired by mining company. Besides drilling, channel sampling can be conducted much more rapidly based on the ply by ply sampling. moreover it requires much cheaper budget than drilling. Although the geometrical support is totally different, drilling sampling is better in term of less subjected by dillution. This study evaluates the implication of drilling and sampling patterns to the spatial heterogencity of coal deposit based on geostatistical approach. The spatial heterogeneity was represented by variogram parameters principally the nugget ratio and range as well as the estimation error of coal properties by kriging method. The case study was conducted for a coal seam of Tanjung Formation at South Kalimantan. The existing drilling and sampling patterns was approximately triangular with much more number of data, and then they were compared to the square pattern by reducing some data. Obviously the less number of data would generate the increasing of error estimate. When the increasing of error estimate was not major anymore, subseguently the drilling and sampling pattern was considered to be optimum.