Abstract
In the current context, where mining companies are dealing more frequently with low-grade, evaluating and implementing ore sorters seems to be one of the favourite technologies used by companies to maximize their deposit profits.
Ore sorters offer a range of benefits to mining operations. Among them, the industry has been captivated by the possibility of improving resource utilization by lowering cut-off values. These values can be lowered by upgrading the plant feed through pre-concentration and, consequently, mining reserves can be increased. Mine sectors that were not profitable before can be evaluated, and even material from waste dumps can be included in the analysis.
To appreciate these benefits, it is necessary to recalculate cut-off values and define or redefine a cut-off policy. This process is a multidisciplinary effort that tends to lead professionals through endless discussions.
Based on a case study in an underground mine, this paper will present the considerations and critical information needed to develop a cut-off grade policy when an ore sorter is incorporated into the operation. This guideline will consider an approach where processing recoveries and costs are functions of the feed grade. The presentation will also emphasize the areas where professionals should focus on optimizing the cut-off value and developing a cut-off value policy according to their corporate goals.