Purpose Despite 20 years of research, there remains no robust, globally agreed upon method-or even problem statement-for assessing mineral resource inputs in life cycle impact assessment (LCIA). As a result, inclusion of commonly used methods such as abiotic depletion potential (ADP) in life cycle assessment (LCA)-related evaluation schemes could lead to incorrect decisions being made in many applications. In this paper, we explore in detail how to improve the way that life cycle thinking is applied to the acquisition of mineral resources and their metal counterparts. Methods This paper evaluates the current body of work in LCIA with regard to Bdepletion potential^of mineral resources. Viewpoints from which models are developed are described and analyzed. The assumptions, data sources, and calculations that underlie currently used methods are examined. A generic metal-containing product is analyzed to demonstrate the vulnerability of results to the denominator utilized in calculating ADP. The adherence to the concept of the area of protection (AOP) is evaluated for current models. The use of ore grades, prices, and economic availability in LCIA is reviewed.Results and discussion Results demonstrate that any work on resource depletion in a life cycle context needs to have a very clear objective or LCIA will not accurately characterize mineral resource use from any perspective and decision-making will continue to suffer. New, harmonized terminology is proposed so that LCA practitioners can build better mutual understanding with the mineral industry and recommendations regarding more promising tools for use in life cycle sustainability assessment (LCSA) are given. Conclusions The economic issue of resource availability should be evaluated in parallel with traditional LCA, not within. LCIA developers should look to economists, the market, and society in general, for broader assessments that consider shorter-time horizons than the traditional LCIA methods. To do so, the concept of the AOP in LCA needs to be redefined for LCSA to ensure that models estimate what is intended. Finally, recommendations regarding mineral resource assessment are provided to ensure that future research has a sound basis and practitioners can incorporate the appropriate tools in their work.

No abstract

This paper captures some of the emerging consensus points that came out of the workshop "Mineral Resources in Life Cycle Impact Assessment: Mapping the path forward", held at the Natural History Museum London on 14 October 2015: that current practices rely in many instances on obsolete data, often confuse resource depletion with impacts on resource availability, which can therefore provide inconsistent decision support and lead to misguided claims about environmental performance. Participants agreed it would be helpful to clarify which models estimate depletion and which estimate availability, so that results can be correctly reported in the most appropriate framework. Most participants suggested that resource availability will be more meaningfully addressed within a comprehensive Life Cycle Sustainability Assessment framework rather than limited to an environmental Life Cycle Assessment or Footprint. Presentations from each of the authors are available for download [1].

No abstract

The concept of declining availability due to declining primary resource quality has been investigated for various resource categories to try to determine the effort needed in future to either extract the resource or to treat it for intended use. The concept of 'future efforts' due to declining primary resource quality is explored by Vieira et al. (2016. They suggest that a specific burden associated with the production of each primary material should be taken into account and that this can be done by studying the costs of production or ore requirements of the material and by projecting forward likely costs into the future. For the purpose of the analysis, they employ mine cost data for 2000-2013 and reserve data published by the US Geological Survey. We will argue below that this approach is not correct and, with this comment, we wish to make it clear that-contrary to what is suggested in much of the Life Cycle Assessment literature-the future efforts concept is not an established rule of natural resource extraction. For mineral resources, it is quite impossible to proceed with extraction in the ordered way that this approach suggests because nobody has a comprehensive view of the entire natural resource. Secondly, there is no evidence available to support the idea that extracting a mineral resource today causes a decrease in availability of that mineral tomorrow. On the contrary, the weight of evidence suggests that where declines in ore grades have been observed, they are overwhelmingly due to technology development in response to high demand and have been accompanied by increased mining efficiency and increased availability of the resource to successive generations. Grade is a rather arbitrary measure since the grade of mined ore ultimately has to do with the relationship of costs and revenues. It is not only the technology employed which matters but also how smartly this technology is applied. Thirdly, the future efforts approach entirely overlooks the potential availability of mineral materials from secondary (scrap) sources, sources which are expected to become increasingly important to mineral supply in the future. Our conclusion from the discussion is that we as humans have been able to economically access ever-increasing amounts of material from often lower and lower-grade sources. What is impossible to conclude from this is that the environment no longer contains any of the higher-grade sources. In fact, all the available evidence suggests that higher-grade deposits are still out there. We remain critical optimists.

Purpose The methods for assessing the impact of using abiotic resources in life cycle assessment (LCA) have always been heavily debated. One of the main reasons for this is the lack of a common understanding of the problem related to resource use. This article reports the results of an effort to reach such common understanding between different stakeholder groups and the LCA community. For this, a top-down approach was applied. Methods To guide the process, a four-level top-down framework was used to (1) demarcate the problem that needs to be assessed, (2) translate this into a modeling concept, (3) derive mathematical equations and fill these with data necessary to calculate the characterization factors, and (4) align the system boundaries and assumptions that are made in the life cycle impact assessment (LCIA) model and the life cycle inventory (LCI) model. Results We started from the following definition of the problem of using resources: the decrease of accessibility on a global level of primary and/or secondary elements over the very long term or short term due to the net result of compromising actions. The system model distinguishes accessible and inaccessible stocks in both the environment and the technosphere. Human actions can compromise the accessible stock through environmental dissipation, technosphere hibernation, and occupation in use or through exploration. As a basis for impact assessment, we propose two parameters: the global change in accessible stock as a net result of the compromising actions and the global amount of the accessible stock. We propose three impact categories for the use of elements: environmental dissipation, technosphere hibernation, and occupation in use, with associated characterization equations for two different time horizons. Finally, preliminary characterization factors are derived and applied in a simple illustrative case study for environmental dissipation. Conclusions Due to data constraints, at this moment, only characterization factors for “dissipation to the environment” over a very-long-term time horizon could be elaborated. The case study shows that the calculation of impact scores might be hampered by insufficient LCI data. Most presently available LCI databases are far from complete in registering the flows necessary to assess the impacts on the accessibility of elements. While applying the framework, various choices are made that could plausibly be made differently. We invite our peers to also use this top-down framework when challenging our choices and elaborate that into a consistent set of choices and assumptions when developing LCIA methods.

Environmental dissipation is a novel approach to account for impacts from mineral resources. In contrast to all other resource‐related life cycle impact assessment methods, which use data on extractions as input to calculation of indicator scores, environmental dissipation is characterized solely through emissions to the environment. Making environmental dissipation work as a viable resource use impact category in life cycle assessment requires, however, that truly dissipative emissions are differentiated from those anthropogenic releases which do not contribute to loss of accessibility of a given resource over the time frame considered. We present a new method that allows for this differentiation to be made for 65 metals and metalloids in a consistent way. It determines (1) whether an emission flow reported in a life cycle inventory actually contributes to loss of accessibility of a given element when environmental fate mechanisms are considered, and (2) whether the element comes from a source that would be considered as a mineral resource for any generation living between the present and the time frame of assessment. We apply the new method to four different emission inventories, and characterize the resulting list of truly dissipative emissions using recently proposed long‐term environmental dissipation potentials (EDP). This highlights the need to differentiate dissipative emissions from other anthropogenic, potentially nondissipative emission flows of elements in metal resource impact assessment.

No abstract