|Title||What do we know (and not know) about the mobility of critical metals in mine waste?|
|Author||Jamieson, H E;
Borcinová Radková, A; Kazamel, B; Des Roches, S; Leybourne, M;
Parsons, M B; Falck, H|
|Source||Virtual Symposium 2021 on Mines and the Environment, technical program; 2021 p. 1-13 Open Access|
|Links||Online - En ligne (June 15 juin, Session C)|
|Alt Series||Natural Resources Canada, Contribution Series 20210031|
|Publisher||Canadian Institute of Mining, Metallurgy and Petroleum|
|Meeting||Symposium 2021 on Mines and the Environment; June 14-16, 2021|
|File format||html; docx|
|Subjects||environmental geology; geochemistry; mineralogy; Economics and Industry; Nature and Environment; Science and Technology; environmental studies; environmental impacts; mining; metals; tungsten; antimony;
mine waste products; waste disposal; tailings; acidity; leaching; minerals; scheelite; modelling; Mining industry; cumulative effects|
|Illustrations||tables; photomicrographs; plots; bar graphs; photographs; pie charts|
|Program||Environmental Geoscience Cumulative effects in cobalt watersheds|
|Released||2021 06 01|
|Abstract||Critical metals are elements that are vital for modern technology, yet there is a real or perceived risk of disruption in their supply. Growing global demand for products using these metals, such as
electric cars, cell phones and wind turbines, is leading to an increase in the mining of these resources. Critical metals are commonly mined as the main target commodity (e.g., rare earth elements (REEs), niobium and tungsten), but others are
extracted as by-products of the mining of major mineral commodities (cobalt, indium, germanium). Very little is known about the environmental mobility of many critical metals, particularly how they are leached from primary host minerals, mobilized
under different conditions of pH and redox, and potentially sequestered in secondary phases. Weathered mine wastes provide an excellent opportunity to study mineral-water interactions involving critical metals.|
This presentation will focus on the
environmental mobility of tungsten, antimony and rare earth elements (REEs). In mine waste, the mobility of antimony is highly dependent on which secondary minerals are stable. Tripuhyite (FeSbO4) is relatively insoluble, whereas brandholzite
((Mg[Sb(OH)6]2•6(H2O) may be a temporary and ephemeral secondary host. Our research has shown that scheelite (CaWO4), the major ore mineral of tungsten, is stable after more than 50 years of exposure to acid drainage. Low concentrations of tungsten
are mobile in pH-neutral surface water as dissolved species and adsorbed to colloidal iron oxyhydroxides. Most primary minerals hosting REEs are relatively insoluble, but REEs can still be transported in surface and ground-waters when adsorbed to
iron oxyhydroxide and organic colloids. The presence of even trace amounts of sulfide minerals in host rocks is important in creating micro-environments that mobilize REEs.
Our emerging understanding of the geochemical behaviour of critical
metals in the near-surface environment is important for guiding waste management decisions at existing and new mines. However, there are few guidelines for the maximum concentration of these elements in water, soil or sediment - how much is too much?
To resolve this, we need toxicological data that are relevant to the mine waste environment to combine with geochemical data and modeling results to help inform the environmentally responsible production of critical metals in Canada.
|Summary||(Plain Language Summary, not published)|
In recent years, there has been a rapid increase in the global demand for many elements used in green energy and high tech applications, including
antimony (Sb), cobalt (Co), lithium (Li), niobium (Nb), tungsten (W) and the rare earth elements (REEs). Canada has an abundance of these critical minerals, and many companies are working hard to bring new mines into production. However, our current
understanding of the potential environmental impacts associated with critical minerals mining is lacking compared to that for other commodities. This presentation discusses recent research on the environmental mobility of tungsten, antimony and REEs
in mine wastes, and the importance of this knowledge for guiding waste management decisions at existing and new mines. The Government of Canada announced its first ever list of critical minerals in March 2021, and this information will help to inform
the environmentally responsible production of these important resources in the future.