Geostatistical Models and Estimation of Laterite Nickel Ore Reserves, Marombo Block, South Sulawesi

Abstract

Abstract Geostatistical modeling in this study requires a distribution of drill points that have a fixed dimension so that they can produce a reserve accuracy match that is the same as the variograph. The choice of reserve estimation method is prioritized by determining the geological domains of limonite, saprolite and bedrock through a geostatistical approach, namely ordinary krigging (OK) and inverse distance weight (IDW) with the JORC standard (2012), for the accuracy of the limonite and saprolite zone boundaries. The reserve model has shown a definite model of the limonite and saprolite zones and can be used further. By using simulations on cut-off grade (COG) to calculate resources and classify mineral resources, the estimation results obtained mean nickel levels above 1.40% so that the CoG to be used must be greater than Ni 0.90% for limonite, and Ni 1.10% for saprolite. The results of modeling the geometry of laterite nickel ore obtained that the total tonnage shown in limonite was 0.36 wmt (wet metric ton), inferred 0.10 wmt, and indicated in saprolite was 0.58 wmt, inferred was 0.40 wmt.