“Reasonable prospects” in mineral resource estimation and reporting

Abstract

ABSTRACT A fundamental component of the Definition Standards for Mineral Resources is the requirement that the material have “reasonable prospects for eventual economic extraction” (RPEEE). The first adoption of the RPEEE requirement by a widespread group was in 1997 as part of the Denver Accord meeting and has since become an international standard. Mineral resource statements are prepared for mineral properties that are at various stages in the mining cycle, from the discovery stage through to the production stage. The confidence level of information available for the development of the input parameters for the technical and economic components of RPEEE varies greatly among stages. Consequently, the RPEEE assumptions may evolve with the stage of the mineral property as well. The economic aspects of RPEEE are commonly achieved by selecting appropriate input parameters for establishing a cut-off grade. The technical aspects can include consideration of such items as minimum widths, spatial continuity, and the application of appropriate constraining surfaces and volumes. In all cases, the responsibility of ensuring that the mineral resource statements are prepared in accordance with the requirements of the Canadian Institute of Mining, Metallurgy and Petroleum Definition Standards ultimately resides with the qualified person.