Aplicação da geoestatística na estimativa e classificação de recursos de um depósito de cobre

Abstract

The purpose of this study was use an appropriate methodology for quantify and classify mineral resources in order to achieve a reliable database for the following stages of planning, essentials for any mining project. It was used data from drilling campaign of cooper deposit, adding up 13.381 samples. All the drill holes were analyzed for to check the integrity of the database. The drill holes were interpreted in vertical and horizontal sections for definition of geological model of deposit using Datamine Studio 2 software. The spatial continuity analysis was realized through construction of variograms Down the hole, omnidirectional and directional for cooper and density. The mineral resources were estimated through geoestatistical method of Ordinary Kriging and classified according JORC CODE of classification mineral resources and reserves. In the semivariogram model validation was obtained both for cooper and density a residual error mean close to zero and correlation between estimated values and real ones greater than 60%, validating the spatial continuity model. It was presented good results also in validation of resource model by global statistics analysis with differences between composites and estimated blocks of 12% for cooper and 0,7% for density, showing a slight underestimation of the global mean. Equally were presented good results for visual validation and good reproduction of the samples global mean into estimated blocks in the swath plots, mainly in the most densely sampled areas. The measured, indicated and inferred mineral resources of cooper deposit were added 923 Mt with 0,23% of cooper, being 282,62 Mt of proven reserves with cooper mean grade of 0,4% and a potential reserve of 638,45 Mt.