ABSTRACT
Tabular deposits are known to have two dimensions much larger than a third one (e.g., bauxite deposits, gold reefs, coal strata). Grade estimation in these deposits is often performed at regular Cartesian grids, whose blocks have the same size. The problem is that regular Cartesian grids do not adapt well to the geological solid used to define the shape and volume in this kind of mineral deposit. Better modeling of the geological solid may be obtained with unstructured grids, whose blocks have different sizes. This work presents the use of these grids for grade estimation in a bauxite deposit. The methodology to build the unstructured grid is shown. Then the grades were estimated in the unstructured grid by ordinary kriging. The resulting grade model was checked by visual inspection, swath plot, and cross validation. Results showed that the estimates reproduced the trend of the data and were globally unbiased.
