Currently, PT. Adaro Indonesia uses the polygonal method to estimate coal resources in the concession area, both quantity and quality. This method was chosen because previous research shows that the geological conditions in this area are moderate. The problem faced in using this method is that the quality of coal in the same coal seam can sometimes vary.

In this research, Geostatistical methods are applied to analyze the spatial relationships between all data, especially drill hole data, from exploration activities. The geostatistical simulation method used to calculate coal resources and quality is the usual kriging approach using a spherical variogram

As a result of this research, the omnidirectional variogram model shows that the coal deposited in this area is 185.54 mt (66.67 mt of inferred resources, 34.04 mt of indicated resources and 84.83 mt of measured resources). Meanwhile, using a variogram model in the direction of strike, coal resources are 183.22 mt (66.87 mt of inferred resources, 34.08 mt of indicated resources and 82.27 mt of measured resources). This research also concludes that there is no direct relationship between coal quality parameter values.

 

 

Nowadays, PT. Adaro Indonesia uses polygonal methods to estimate coal resources at its concession area, both quantity and quality. This method was chosen because in the previous research it was shown that the geological condition in this area was moderate. The problems faced in using this method are the coal quality in the same coal seam sometimes may vary.

In this research, Geostatistics method was applied to analyze spatial correlation between all data, specifically drill hole data, from exploration activities. The geostatistical simulation method used to calculate resources and the quality of coal is ordinary kriging approach using spherical variogram.

As the result of this research, using omnidirectional variogram model shows that coal deposited in this area is 185.54 mt (66.67 mt inferred , 34.04 mt indicated and 84.83 mt measured ). While using in-line-strike variogram model, the quantity coal is 183.22 mt (66.87 mt inferred , 34.08 mt indicated and 82.27 mt measured ). This research also gave a conclusion that there was no direct relationship between coal quality parameters.