EVOLUTION OF ORE-RESERVE ESTIMATION STRATEGY AND METHODOLOGY AT NEVES CORVO COPPER TIN MINE, PORTUGAL

The Neves-Corvo deposit, discovered in 1977, has become Europe's main producer of copper and tin. As the project progressed from exploration, through technical and economic feasibility studies, to construction and successful operation the role of geological evaluation and ore-reserve estimation was fundamental. The choice of geological data collected, interpretative techniques and estimation methods changed in response to the sequence of questions posed during technical and financial planning. For each phase of the project a different type of three-dimensional geological interpretation and reserve model was established. The generation of these models is based on the integration of geological data collection and interpretation with computer-based estimation techniques. The resulting ore reserve is a structured inventory of reserve models, each category of which contains sufficient detail of geological and grade variations for the planning period during which it will be used. A case history is presented in which the evolution of the current reserve system of an operating underground base-metal mine is described, with particular emphasis on the role of geology as the foundation of such a system.