Using geostatistics as a tool in fine tuning of iron ore resource modelling / Использование геостатистики в качестве инструмента для точной настройки моделирования ресурсов железной руды

The aim of this paper is to demonstrate the importance of using variography for grade interpolation in multielement environments and to illustrate how variography can assist in the understanding of geological controls on mineralisation.
Variography codes mineralisation continuity numerically and it is one of the first links between geology and mine planning, since it guides the choice of the interpolation technique. Owing to advances in computer technology and new visualisation techniques, semi-variogram analysis is becoming more of a routine procedure during both feasibility studies and on operating mines.
It is a complex and challenging task to produce a high quality model for an iron ore deposit as iron and the numerous contaminants all have different grade distributions, different spatial orientations and different degrees of variability. In addition, even within a single well-defined geological domain, several populations of mineralisation are often found. Because of these complexities, resource modelling often requires the application of non-parametric interpolation methods.
The spatial continuity of two contaminant elements in ‘N’ domain was carried out for an iron ore deposit (mineralised banded iron formation). Grade values for the both contaminants form positively skewed data distributions with evidence of mixed populations. Directions of maximum continuity were interpreted for each population percentile for both contaminants. Structural controls affecting the levels of both contaminants were confirmed or established. <...>