RESUMEN
There has been increasing attention recently to reprocessing of mining waste, which aims to recover potentially valuable materials such as metals and other byproducts from untapped resources. Mining waste valorization may offer environmental advantages over traditional make-waste-dispose approaches. However, a quantitative environmental assessment for large-scale reprocessing, accounting for future trends and a broad set of environmental indicators, is still lacking. This article assesses the life cycle impacts and resource recovery potential associated with alternative waste management through mine tailings reprocessing at a regional scale. Sulfidic copper tailings in the EU were selected as a case study. We perform prospective life cycle assessments of future reprocessing scenarios by considering emerging resource recovery technologies, market supply & demand forecasts, and energy system changes. We find that some reprocessing and valorization technologies in future scenarios may have reduction potentials for multiple impact indicators. However, results for indicators such as climate change and energy-related impacts suggest that specific scenarios perform sub-optimally due to energy/resource-intensive processes. The environmental performance of reprocessing of tailings is influenced by technology routes, secondary material market penetration, and choices of displaced products. The trade-off between climate change and energy related impacts, on the one hand, and toxicity impacts, on the other hand, requires critical appraisal by decision makers when promoting alternative tailings reprocessing. Implementing value recovery strategies for building material production, can save up to 3 Mt. CO2-eq in 2050 compared to business as usual, helping the copper sector mitigate climate impacts. Additional climate mitigation efforts in demand-side management are needed though to achieve the 1.5 °C climate target. This work provides a scientific basis for decision-making toward more sustainable reprocessing and valorization of sulfidic tailings.
RESUMEN
Worldwide, an issue of copper production is the generation of mine waste with varying characteristics. This waste can pollute natural environments, and in particular, the heavy metal emissions of the tailings may pose long-term consequences. Currently, life cycle assessments of mine tailings are hampered by both limited data availability in the metal production value chain and lack of appropriate methodologies. We collect data from 431 active copper mine sites using a combination of information available from the market research and technical handbooks to develop site-specific life cycle inventories for disposal of tailings. The approach considers the influences of copper ore composition and local hydrology for dynamically estimating leached metals of tailings at each site. The analysis reveals that together, copper tailings from the large (i.e., porphyry) and medium-size copper deposits (i.e., volcanogenic massive sulfide and sediment-hosted) contribute to more than three quarters of the total global freshwater ecotoxicity impacts of copper tailings. This strongly correlates with hydrological conditions, leading to high infiltration rates. The generated inventories vary locally, even within single countries, showcasing the importance of site-specific models. Our study provides site-specific, dynamic emission models and thus improves the accuracy of tailing's inventories and toxicity-related impacts.
