ABSTRACT
Mineral resource classification is described in both the SME and CIM Standards for Mineral Resource Reporting. The CIM Standard states “… sampling … is sufficient to assume geological and grade or quality continuity between points of observation”, thus is a function of continuity and sample spacing. Continuity can be measured by use of a variogram model, but average sample spacing in three dimensions is more difficult to measure. The declustering algorithms provided with geostatistics software are commonly used to weight data for statistical analysis due to the sometimes-irregular spacing between drill holes during exploration. The weight values are lower when data is closer, reflecting shared influence between samples, and higher for isolated samples reflecting independence. This paper will discuss the potential to use estimates of these declustering weights as an inverse relative measure for average sample spacing to gauge the confidence of the estimate independent of the single nearest sample.
