Getting it right: preliminary information required to evaluate gold prospects in privatizing economies

摘要

An attempt is made to provide a summary of the main sources of potential error in gold prospect evaluation that could serve as an aid when the problems of estimating grade and tonnage need to be explained to non-experts. The summary covers how to approach the problems of drill-hole spacing and orientation relative to mineralization to arrive at a correct geological interpretation, how bias may be introduced-and avoided-at the stages of drilling, sampling and asaying and how to obtain a two-sided interval estimate from the results of a drilling programme. Particular attention is paid to the uses of orebody classification based on the coefficient of variation, Gy's formula and half absolute relative difference plots.