Drilling Grid Analysis for Defining Open-Pit and Underground Mineral Resource Classification through Production Data

Abstract

The varied types of mineral deposits and geological features around the world have led to the creation of a large number of techniques, methodologies, and definitions for mineral resource classification. The most common methods used in the mineral industry include kriging variance, drilling spacing, neighborhood restriction, and conditional simulations. These methods generally do not use reconciled production information, only long-term borehole information based on personal judgment for defining confident intervals/limits on the mineral resource classification. A drilling spacing back analysis study for defining mineral resource classification was completed considering tonnages and grades confidence intervals related to its respective production volumes, based on short-term production reconciliation of analog deposits. The definition of adequate drill holes spacing and detailed results for classifying mineral resources are demonstrated by both an open-pit and an underground project adjacent to an existing mining operation. This study has considered a Brazilian sulfide deposit (Cu-Au) operating mine as analog information.