Life cycle assessment in the minerals and metals sector: a critical review of selected issues and challenges

Background, aim and scopeThe mining sector provides materials that are essential elements in a wide range of goods and services, which create value by meeting human needs. Mining and processing activities are an integral part of most complex material cycles so that the application of life cycle assessment (LCA) to minerals and metals has therefore gained prominence. In the past decade, increased use of LCA in the mineral and metal sector has advanced the scientific knowledge through the development of scientifically valid life cycle inventory databases. Though scientifically valid, LCA still needs to depend on several technical assumptions. In particular, measuring the environmental burden issues related to abiotic resource depletion, land use impacts and open-loop recycling within the LCA are widely debated issues. Also, incorporating spatial and temporal sensitivities in LCA, to make it a consistent scientific tool, is yet to be resolved. This article discusses existing LCA methods and proposed models on different issues in relation to minerals and metals sector.Main featuresA critical review was conducted of existing LCA methods in the minerals and metals sector in relation to allocation issues related to indicators of land use impacts, abiotic resource depletion, allocation in open-loop recycling and the system expansions and accounting of spatial and temporal dimension in LCA practice.ResultsEvolving a holistic view about these contentious issues will be presented with view for future LCA research in the minerals and metals industry. This extensive literature search uncovers many of the issues that require immediate attention from the LCA scientific community.DiscussionThe methodological drawbacks, mainly problems with inconsistencies in LCA results for the same situation under different assumptions and issues related to data quality, are considered to be the shortcomings of current LCA. In the minerals and metals sector, it is important to increase the objectivity of LCA by way of fixing those uncertainties, for example, in the LCA of the minerals and metals sector, whether the land use has to be considered in detail or at a coarse level. In regard to abiotic resource characterisation, the weighting and time scales to be considered become a very critical issue of judgement. And, in the case of open-loop recycling, which model will best satisfy all the stake holders? How the temporal and spatial dimensions should be incorporated into LCA is one of the biggest challenges ahead of all those who are concerned. Addressing these issues shall enable LCA to be used as a policy tool in environmental decision-making. There has been enormous debate with respect to on land use impacts, abiotic resource depletion, open-loop recycling and spatial and temporal dimensions, and these debates remain unresolved. Discussions aimed at bringing consensus amongst all the stake holders involved in LCA (i.e. industry, academia, consulting organisations and government) will be presented and discussed. In addition, a commentary of different points of view on these issues will be presented.ConclusionsThis review shall bring into perspective some of those contentious issues that are widely debated by many researchers. The possible future directions proposed by researchers across the globe shall be presented. Finally, authors conclude with their views on the prospects of LCA for future research endeavours.Recommendations and outlookSpecific LCA issues of minerals and metals need to be investigated further to gain more understanding. To facilitate the future use of LCA as a policy tool in the minerals and metals sector, it is important to increase the objectivity with more scientific validity. Therefore, it is essential that the issues discussed in this paper are addressed to a great detail.

[1]  Jane C. Bare,et al.  Life cycle impact assessment sophistication , 1999 .

[2]  Thomas Ohlsson,et al.  A comparison of two different approaches to inventory analysis of dairies , 1998 .

[3]  Frank Brentrup,et al.  Impact assessment of abiotic resource consumption conceptual considerations , 2002 .

[4]  Hans-Jürgen Dr. Klüppel,et al.  The Revision of ISO Standards 14040-3 - ISO 14040: Environmental management – Life cycle assessment – Principles and framework - ISO 14044: Environmental management – Life cycle assessment – Requirements and guidelines , 2005 .

[5]  Frank Brentrup,et al.  Life Cycle Impact assessment of land use based on the hemeroby concept , 2002 .

[6]  Dennis L. Meadows,et al.  Limits to growth : the 30-year update , 2004 .

[7]  Alan C. Brent,et al.  Characterisation and Normalisation Factors for Life Cycle Impact Assessment Mined Abiotic Resources Categories in South Africa: The manufacturing of catalytic converter exhaust systems as a case study (10 pp) , 2006 .

[8]  J. William Owens,et al.  LCA impact assessment categories , 1996 .

[9]  Helias A. Udo de Haes,et al.  Sustainable Management of Natural Resources in an Life-cycle Perspective (Issue Editor: Helias A. Udo de Haes) , 2006 .

[10]  Alan C. Brent,et al.  The Impact of Mineral Resource Depletion , 2006 .

[11]  Walter Klöpffer,et al.  Allocation rule for open-loop recycling in life cycle assessment , 1996 .

[12]  Adisa Azapagica,et al.  Allocation of Environmental Burdens in Multiple-function Systems , 1999 .

[13]  T. Ekvall.  A market-based approach to allocation at open-loop recycling , 2000 .

[14]  Thomas Köllner,et al.  Species-pool effect potentials (SPEP) as a yardstick to evaluate land-use impacts on biodiversity , 2000 .

[15]  R. Frischknecht,et al.  A special view on the nature of the allocation problem , 1998 .

[16]  J. Atherton.  Declaration by the Metals Industry on Recycling Principles , 2007 .

[17]  J. Jacobs,et al.  The Economy of Cities , 1969 .

[18]  R. Biggs,et al.  A biodiversity intactness index , 2005, Nature.

[19]  Göran Finnveden,et al.  The Resource Debate Needs to Continue [Stewart M, Weidema B (2005): A Consistent Framework for Assessing the Impacts from Resource Use. Int J LCA 10 (4) 240−247] , 2005 .

[20]  Kun-Mo Lee,et al.  Allocation for cascade recycling system , 1997 .

[21]  Göran Finnveden,et al.  Impacts from Resource Use - A common position paper , 2005 .

[22]  Fabio Giudice,et al.  Product Design for the Environment: A Life Cycle Approach , 2006 .

[23]  M. Hauschild,et al.  Part II: spatial differentiation in life-cycle assessment via the site-dependent characterisation of environmental impact from emissions , 1997 .

[24]  Mary Stewart,et al.  A Consistent Framework for Assessing the Impacts from Resource Use - A focus on resource functionality (8 pp) , 2005 .

[25]  Roland Clift,et al.  Expert Workshop on Land Use Impacts in Life Cycle Assessment. 12–13 June 2006 Guildford, Surrey (UK) , 2006 .

[26]  J. W. Owens.  Life‐Cycle Assessment: Constraints on Moving from Inventory to Impact Assessment , 1997 .

[27]  M. Hauschild.  Spatial Differentiation in Life Cycle Impact Assessment: A decade of method development to increase the environmental realism of LCIA , 2006 .

[28]  P. Hofstetter.  The value debate: ecodesign in a global context are there differences in global values and do they matter? , 2002 .

[29]  R. Schenck.  Land use and biodiversity indicators for life cycle impact assessment , 2001 .

[30]  Bengt Steen.  Abiotic Resource Depletion Different perceptions of the problem with mineral deposits , 2006 .

[31]  C. Bauer,et al.  Key Elements in a Framework for Land Use Impact Assessment Within LCA (11 pp) , 2007 .

[32]  Anna Björklund,et al.  Survey of approaches to improve reliability in lca , 2002 .

[33]  William E. Franklin,et al.  General mathematical models for LCI recycling , 1994 .

[34]  Reinout Heijungs,et al.  The structure of impact assessment: Mutually independent dimensions as a function of modifiers , 1999 .

[35]  Mark A. J. Huijbregts,et al.  Application of uncertainty and variability in LCA , 1998 .

[36]  Frank R. Field,et al.  Explicit accounting methods for recycling in LCI , 1998 .

[37]  Gerald Rebitzer,et al.  The LCIA midpoint-damage framework of the UNEP/SETAC life cycle initiative , 2004 .

[38]  Walter Klöpffer,et al.  Life cycle assessment , 1997, Environmental science and pollution research international.

[39]  Tomas Ekvall,et al.  Open-loop recycling: Criteria for allocation procedures , 1997 .

[40]  W. Howells,et al.  Yesterday, Today and Tomorrow , 1992 .

[41]  Göran Finnveden,et al.  Allocation in ISO 14041—a critical review , 2001 .

[42]  Edgar Furuholt,et al.  Life cycle assessment of gasoline and diesel , 1995 .

[43]  Alan C. Brent,et al.  The Impact of Mineral Resource Depletion - In response to Steen BA (2006): Abiotic Resource Depletion: Different perceptions of the problem with mineral deposits. Int J LCA 11 (Special Issue 1) 49-54 , 2006 .