Geostatistics and ore reserve classification

CIM Bulletin, Vol. 75, No. 843, 1982

ROLAND FROIDEVAUX, David S. Robertson & Associates, Toronto, Ontario

The main object of ore reserve classification is to assess the reliability of an ore reserve estimate. Because traditional classification schemes fail to provide a means of calculating this reliability, the terms 'proven', 'probable' and 'possible' ore were introduced as an attempt to qualify it.Geostatistics, on its part, allows the quantification of the precision of any ore estimate and thus appears as an appropriate tool for ore reserve classification.However, the problem affixing quantitative boundaries for ore classes remains. In order to be meaningful, ore class limits based on the degree of reliability should be customized to the commodity, and the type and size of the deposit. In addition, the precision of an ore estimate will be affected by the cut-off grade and the size of selective mining units.
Keywords: Geostatistics, Ore reserves, Reserve classifications, McKelvey box, Estimation variances, Simulation, Mineral deposits.