Geometalurgia aplicada ao planejamento de lavra através de sequenciamento direto de blocos em depósitos de cobre e ouro

Abstract

Mine planning is a critical step in mining and aims to generate production scenarios focused on the economic and sustainable use of mineral resources. Geometallurgy is a multidisciplinary approach that purposes to connect different areas of the mineral value chain, seeking greater precision in the decision-making process, since it can indicate possible bottlenecks throughout the life of the mine, reducing business risks. Despite this, the inclusion of geometallurgical variables in the block model is still incipient in mining. The objective of this study was to show the importance and impacts of geometallurgy in mine planning, using an easy, fast and lowcost methodology that ranges from obtaining comminution indices to mining scheduling. The first study used a synthetic and public block model (Marvin) to compare mining scheduling with and without geometallurgical variables. The results indicated that in the scenario with geometallurgical variables, the economic return was lower than in the scenario without geometallurgical variables, indicating a possible optimism in the assumptions adopted in the conventional scenario. The second study was carried out with a database of a real mine that has a large number of comminution tests obtained through the HIT (Hardness Index Tester). The HIT provides the comminution indices A*b and BWI, which are considered non-additive variables. Two geometallurgical block models were generated, one considering the spatial interpolation of the comminution indices A*b and BWI and the other considering the spatial interpolation of the specific energy. Production plans were generated through direct block scheduling for the two geometallurgical block models and the results showed a non-significant difference (0.54%) in the Net Present Value (NPV), despite there being differences in the scheduling of the blocks in each scenario. It can be concluded that the spatial interpolation method did not influence the final economic result for the studied mine. The research developed shows how to obtain comminution indexes and how to use them in the geometallurgical scheduling of mining. It is expected that other mines will use the presented methodology to reduce risks in relation to productivity estimates (t/h).