Originally, Life Cycle Assessment used estimates of total crustal content to calculate how many years’ worth of natural resource existed. Later, practitioners began limiting existing stocks to those identified by the United States Geological Survey in its annual Commodity Summaries. (See, for example the EU's Product Environmental Footprint resources). Because of the nature of the equations used, LCA results are highly sensitive these differences in assumed total stock of abiotic resources. There is increasing international consensus that this aspect of Life Cycle Impact Assessment is well and truly broken and in need of an entire re-think.
More recently, several researchers have suggested that metal production has peaked, that resources will be depleted within decades and that declining ore grades can be used to forecast a time when mining will no longer be viable. This has underlined a lack of cross-disciplinary understanding of Mineral Economics.
In a new peer-reviewed publication, "Mineral resources in life cycle impact assessment—defining the path forward", we have come forward with probably the first globally coordinated mining industry contribution to the last twenty years of research into resource assessment in Life Cycle Thinking.
In the paper (which is freely available for download), exploration, geology, and economic experts from the global mining industry provide recommendations to ensure that future research into mineral resource assessment has a sound basis and that practitioners can utilize more appropriate tools for their work.
The paper's findings were recently debated at an International Workshop co-hosted by the Natural History Museum London (follow link for access to all presentations).