Fixing Panel Artifacts in Localized Indicator Kriging (LIK) Block Models

Abstract

Three types of panel artifacts are created by the localized indicator kriging (LIK) methodology. Two of these artifact types can be fixed (eliminated) by a two-step process that consists of averaging models with different panel origins and then performing a global re-localization. The first type of panel artifact, and probably the most important, is caused by change-of-support transformations, which are independent and applied on a panel-by-panel basis. The second type of artifact is the most common but is usually undetectable. This artifact is caused by the fact that there are several possible LIK models where the only difference is the panel origin, and although each of the resulting models has the same global distribution, the high-grade blocks change location. The third type of artifact is caused by using a search ellipse that is too large (nonstationary), which is more typical in areas where drill data is sparse. Unlike the first two artifact types, this type needs to be fixed by adjusting search parameters. Artifacts should be eliminated from LIK models whether they are obvious as in the case of those caused by large change-of-support transformations or are simply the added spatial noise caused by having more than one origin.