Global Critical Metal Resources; Why We Don't Know How Much We Have

The critical minerals are a group of elements that are essential to modern life but have insecure supply as a result of a variety of factors and are of increasing importance given their use in technologies needed to reduce global CO2 emissions and mitigate against anthropogenic climate change. However, the majority of these critical elements are produced as co- or by-products of other more widely produced metals, meaning that their economic contributions to mining operations are often small and the elements in question are often produced downstream in smelters or refiners. This means that mines may produce a critical element that is unquantified in reserve or resource reporting. Extrapolating this to a global scale yields a situation where we simply are unable to robustly estimate current resources of these crucial elements. This paper reviews the key uncertainties in these areas as well as ways forward to improving the predictability of future production of these critical minerals.