| Abstrak/Abstract |
The calculation of coal reserves is influenced by the dimensions or size of the coal deposit. There are several types of coal reserve calculation methods, and the use of these methods is adjusted to existing geological conditions. Each method will produce a different amount of coal reserves, although the location is the same. This research compares coal reserve estimation methods with a case study in PT. Bukit Asam Area, South Sumatra, Indonesia. Data on coal thickness and topography are used as the basis for reserves estimation. Several methods are applied to estimate coal reserve: nearest neighbor point (NNP), inverse distance weighted (IDW), and kriging using Surfer 13 software. Coal deposits in the study area belong to the Muara Enim Formation, consisting of seam A1, seam A2, seam B, and seam C. The coal layers have an N 87° E strike and dip 15–40° to the south. Coal in this study area is classified as sub- bituminous rank coal with a coal calorific value <7000> 7000 calories/gram (dry ash-free) in A1, A2, and C seams. The selection of the best method for estimating coal reserves is based on the smallest root mean square error (RMSE) value. RMSE calculations are carried out for each interpolation of coal thickness on Seam A1, Seam A2, Seam B, and Seam C. The reserves estimation results indicate that kriging is the best method by providing the smallest error value with an RMSE value of 0.67 and coal
reserves of 27,801,543 tons. |
