?As is well known, the availability of water for mining processes in Chile is limited. In addition, it should be considered that the vast majority of mining plants are located in the northern part of the country, which is for the most part desert, and mainly at a high altitude. Given the low availability of water, various alternatives have emerged such as thickening tailings to high concentrations by weight (recovering more water in the thickeners) or using desalinated seawater. The present study aims to define the optimum thickening concentration for copper tailings, applied to a case study of representative Chilean mine tailings, from a rheological and energy point of view, as a function of recovered water in the thickeners and specific energy consumption (SEC), transporting one ton of Non-Newtonian thickened tailings. The specific energy consumption (SEC) should be related mostly to the solids transported than to the mixture, with thickening becoming a relevant parameter, since in slurry transport, the solids are usually the "payload", while the conveying fluid is simply the "vehicle". The result of this paper provides the industry with an additional variable to consider in the optimum grade of tailings thickening and rheological design parameters for projects, which could be considered in conceptual and pre-feasibility stages or in the optimization of existing systems.
?Chile is a country with high vulnerability associated with Climate Change, given among other factors, due to the need for development and growing social and environmental conflicts. This motivates the implementation of adaptation, transformation and mitigation measures at all aspects, to deal with climatological phenomena, which despite its future uncertainty, its development is a proven fact by robust and bulky scientific evidence. Motivated by the call from COP25 and the IPCC to assess adaptation and mitigation of effects and consequences of Climate Change, SRK Chile proposed to analyze the response of infrastructure associated with mining in northern Chile, considering General Circulation Models (GCM) downscaled for Atacama region at different elevations, based on the models considered by Chilean Water Directorate (DGA) in its Update of the National Water Balance of Chile (NWBC). This study considers Representative Concentration Pathways RCP 8.5 (most pessimistic scenario) as scenarios to evaluate, same as DGA NWBC. To observe the effects of these scenarios we applied the GCM as boundary conditions in 1D numerical infiltration models using the software Hydrus. In the simulations water fluxes in a column of thickened tailing above natural soil is analyzed for different precipitation regimes from GCMs. Standard values according to our experience for the hydraulic and geometry properties of the materials forming the columns are used. The results of this study shed light upon the future precipitations scenarios affect the available water in the infrastructures at different elevations, providing a quantitative comparison of the infiltration fluxes within the tailing for the GCMs in the Atacama region.
?Chile produces large amounts of tailings daily which must be safely disposed on the earths surface. There are a series of strategies that have been successfully used in our country to store tailings, among them are thickened and paste tailings. Paste tailings are an advantageous technique that allows for greater recovery of water while improving physical stability of the structure. Although challenges are faced worldwide when large production rates are tried to be thickened, the technique seems promising for countries like Chile where there is an ongoing water crisis. The stability of paste tailings facilities is highly influenced by water content or saturation. As consolidation occurs the tailings loses water. However, as the evaporation front takes place, the material goes from a saturated to a non-saturated state. Unsaturated paste has shown improved resistance, e.g. liquefaction resistance almost double when saturation drops below 90%. A well planned facility operation should consider the monitoring of the water content of the paste. However, this is sometimes difficult, due to the large areas that must be controlled and the danger associated with manual moisture measurements in the field. In this context, we proposed the use of hyperspectral cameras to obtain a relationship between the paste moisture content and light reflectance. This would allow to generate moisture surface map and to the use of this data to monitor for instance evaporation rates or water balance in tailings storage facilities. This article summarizes laboratory main findings and proposes a series of procedures to implement the technique in the field.