Mineral resource classification – it’s time to shoot the “spotted dog”! / Классификация минеральных ресурсов – пришло время подстрелить “пятнистого пса”!

Classification of mineral resource estimates is one of the most important responsibilities of the Competent Person. In recent years, classification decisions have been driven more by the detailed block-by-block attributes generated by the now widely appliedgeostatistical estimation methods, and less by a general geological overview. This is increasingly resulting in “spotted dog” outputs, in which blocks of Inferred Resources or unclassified material separate blocks of Measured and/or Indicated Resources, orindividual drillholes are surrounded by annuli of Measured and Indicated Resource blocks. Not only are such outputs potentially misleading since they ignore fundamentals such as continuity of geology and mineralisation between drillholes and the imprecise nature of resource estimation, they can also cause substantial problems for engineers undertaking mine designs and estimating ore reserves, particularly for underground mines. Competent Persons for mineral resources must keep in mind the purpose of their work, and should use their experience and judgment to avoid or smooth out “spotted dog” classifications, providing a result commensurate with the level of geological and resource estimation confidence. For their part, ore reserve Competent Persons must understand the resource estimation and classification process, and should question resource classifications that are not consistent with the level of geological and resource estimation confidence. <...>