LCA as a support to more sustainable tailings management: critical review, lessons learnt and potential way forward
Résumé
This article critically reviews LCAs of tailings management, including disposal, use in construction materials and reprocessing for metal recovery. It explores 28 publications considering goal and scope definition, Life Cycle Inventory (LCI), impact assessment (IA), and interpretation. Lessons learnt are discussed: i) tailings final disposal is an environmental hotspot in the production of several metals and manufactured goods; ii) associated key impacts on human toxicity and ecotoxicity are highly sensitive to metals mobility; iii) uncertainty in LCI modelling is rarely addressed, despite expected to be high; iv) compared to classical routes, tailings use in construction materials globally enables environmental benefits, whereas environmental performance of reprocessing needs further exploration. Moreover, mineral resources accounting in LCI of tailings management is classically inconsistently combined with some depletion- or dissipation-based IA. Yet resource dissipation in LCA is promising towards supporting more resource-efficient management. Finally, this article provides suggestions towards improved LCA of tailings management: i) ensuring compliance with standards; ii) balancing metal flows in LCI modelling; iii) rethinking resources “to” and “in” tailings in LCI/LCIA modelling; iv) developing further waste and technology-specific models of emissions from tailings final disposal; v) setting coherent scenarios of future tailings management to consistently account for emissions and resources.