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Critical minerals · Mining · Heat transport · Solute transport · Permeability
Abstract:
Attaining the goals of the international treaty on climate change (the Paris Agreement) will greatly increase the demand
for the critical minerals required to implement clean-energy technologies. This poses both challenges and opportunities
to the hydrogeologic community from several perspectives. Here, important insights that the hydrogeological sciences
have to offer for mineral exploration, mineral production, and addressing environmental issues related to mining and mine
decommissioning are summarized. This study focuses on copper, cobalt, lithium, and rare earths to represent the broad
spectrum of critical minerals and illustrate their relevance by referring to projected demands and production rates. The
current understanding of the hydrogeologic processes that form major deposits of these minerals are then summarized.
Ore is defined as the naturally occurring material from which minerals of economic value can be extracted, where most ore
deposits are the products of complex hydrogeologic couplings between fluid flow, heat transport, solute transport, chemical
reactions, and mechanical deformation. Exploration models for the discovery of deeper, hidden deposits are potentially
informed by hydrogeologic theory and hydrogeochemical processes. Hydrogeologic understanding and methods are also
essential to production and recovery. Longstanding challenges are mine dewatering and (conversely) mine water supply,
as well as mineral-extraction practices such as spoil heap leaching and in situ mining. New challenges arise from element
extraction from subsurface brines. Finally, the quantity of water use and potential environmental impacts of mining on
water quality are at the core of ‘social license’: the approval and acceptance of society to mining activities.
