Environmental and Economic Implications of Using 2d Reactive Transport Modelling to Anticipate Enrichment/Depletion Processes in Mine Tailings Under Arid Climate

Abstract

Mine tailings (MTs) can be found in most mining districts around the World, being both a potential source of contaminants and also a potential secondary source of critical raw materials. A faster and cheaper alternative to the typical intense drilling campaigns could be the generation of a reactive transport model of the MTs using a few drills. The current study generated a 2D reactive transport model (RTM) of IOCG-type MTs in an arid climate in north Chile. The model is used to reproduce a previous intricate geostatistical model (block size of 5 m ×5 m ×1 m, resulting in a total of 1,800,000 blocks). It combines hydrodynamic parameters, geochemical reactions and transport processes. The RTM was able to simulate the mineralogical evolution of this IOCG-type tailings deposits in an arid climate, reproducing the different depleted/enriched geochemical horizon observed in the field and predicting their small progress on a 50 years period. Thanks to this complexity and multidisciplinary, it provides valuable insights for the operational management of this type of facilities, during both their active and close periods. Its applications extend beyond the specific case presented in this study, as it can be applied for many similar settings around the World.

Keywords: Unsaturated flow, Sulfide oxidation, circular economy, water rock interaction