Critical Issues for Life Cycle Impact Assessment in Minerals Processing and Metals Refining

摘要

Life Cycle Assessment (LCA) is increasingly being used as a decision-support tool within mining and minerals processing and metals production. However, a number of initiatives have highlighted the current limitations of LCA to accurately reflect the environmental performance of minerals and metals. These programs include: 1. the Mining, Minerals and Sustainable development project (Stewart, 2001); 2. the United Nations Environment Programmme/Society for Environmental Toxicology and Chemistry (UNEP/SETAC) workshop on LCA and metals (NRCan, 2002); 3. the UNEP SETAC Life Cycle Initiative; and 4. the review of the existing ISO 14 040 set of environmental management standards. Together, these initiatives highlighted concerns relating to the ability of LCA to engage with and support metals recycling, to adequately reflect the impacts associated with products from a multi-product orebody, the ability to adequately reflect the toxicity potential of metals in the natural environment and the fact that resource depletion focuses on mining (and not consumption) as the depleting activity in the life cycle of a metal. Additional impact categories to be included in LCA were also suggested. In this paper we demonstrate how existing initiatives are addressing LCA limitations. Finally we present the state of the art in Life Cycle Impact Assessment (LCIA) for two impact categories: 1. resource depletion; and 2. impacted land footprint for solid wastes.