Title: Mineral resource classification; it's time to shoot the spotted dog!
Abstract: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 bloc...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 applied geostatistical 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, or individual 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. INTRODUCTION AMC Consultants Pty Ltd (“AMC”) has become increasingly concerned in recent years with mineral resource classification practices that lack both common sense geologically and cause significant difficulties during mine design and conversion to ore reserves, particularly for underground mines. This paper has been prepared by a group of AMC geologists and mining engineers as a practical contribution to the 6 International Mine Geology Conference being held in Darwin in August 2006. It is hoped that the issues highlighted and real examples provided will encourage a more sensible approach to resource classification and make life easier for all concerned. MINERAL RESOURCE CLASSIFICATION – A GEOLOGICAL PERSPECTIVE Introduction The Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (the “JORC Code” 2004) allows for classification of mineral resource esti mates into Inferred, Indicated and Measured Resource categories based on increasing geological confidence in the estimate (JORC, 2004). The JORC Code is deliberately not prescriptive as to how that confidence is determined and relies on the experience and competence of Competent Persons to judge, firstly (if necessary, in conjunction with others), that part of a resource estimate for which there are reasonable prospects for eventual economic extraction and, secondly, the level of confidence that can be attributed to the estimate. InRead More
Publication Year: 2006
Publication Date: 2006-11-11
Language: en
Type: article
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Cited By Count: 2
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