The use of the Net Smelt Return to evaluate a poly metallic deposit: a case study

摘要

As we know, poly metallic deposits are a complex problem. The viability of some projects mainly the low grade/high ratio ones necessarily depend on every return a block can provide. In this sense a multi-metal mineralization can provide several revenues based on each metal, but the decision making process of how to decide which block will be mined and which will be dumped is based on cut-off grade analysis. Several approaches using the breakeven cut-off grade, Lane’s algorithm are straightforward for a single element. When we have a multi-element some approaches like equivalent grade reducing all the metals to the same basis (normally the most expressive at the deposit) expressing the grades of the other metals based on prices and recoveries at the plant. The approach given at this study is focused in using the NSR (Net Smelt Return) to build the profit function for the deposit and then optimize resources using the NPV Scheduler, generating an ultimate pit to delineate the long term mine planning and to determine the viability of the project. In this sense the NSR is the key mixing different parameters like selling price, metallurgical recovery, operational costs and others to get to a number that expresses the profitability of each block.