Estimating recoverable reserves – developments in applied geostatistics / Оценка извлекаемых запасов – достижения в области прикладной геостатистики

So much work has been done in recent years using geostatistics to solve practical problems that we no longer have to apologise for nor justify the method. The method is as good as the practitioner, which goes, after all, for any technical application. There have been enough case studies now to show that almost any orebody, simple or complex in structure, which has a definable spatial continuity, will be amenable to geostatistical evaluation given that it is suitably sampled.
Early kriging techniques catered only for calculating the average grade of a fixed volume of ground which, in structurally complex orebodies would not reflect ultimate selective mining of the orebody but today techniques do cater for estimating recoverable reserves from exploration drilling.
The most useful tool, at the exploration stage, is the semivariogram. This quantifies the range and direction of grade continuity and lends support to geological interpretation. It can highlight potential problems due to insufficiently close spaced drilling or, indeed incorrectly orientated drilling. The relationship between variability and block sizes, which is quantified by the semivariogram, allows one to interpret the degree of selectivity possible for given selective mining units. The classification of the resource or reserve is affected by the range of influence of the semivariograms. <...>