FRACTAL MODEL AND CLASSICAL BLOCK MODEL IN ORE RESERVE ESTIMATION: A COMPARISON

Abstract

The characteristic possessed by many gold deposits is the erratic distribution for gold grade and abnormal distribution (high skewness) which would restrain the application of certain estimation methods especially geostatistics. Another method proposed in order to handle high skewness distribution is fractal model. In this paper one of the models, the number-size model would be compared with block model in estimating ore tonnage and metal (Au-Ag) tonnage for deposit with complex and erratic data distribution. For this purpose, the data obtained from channel sampling program in Ciurug vein, block South 3, level 500 and 600, Pongkor mines would be used as study case. The results show that the number-size fractal model so far could be applied only to the deposits with continuous dimension and grade distribution. For deposits with erratic grade distribution the fractal model has only limited use, which powerful generally to estimate bulk volume or ore tonnage since the dimension i.e. thickness has relatively high continuity.