Oxford Uni. Boffins Say It's Time To Start Mining Volcanoes For Copper

The Register seems to like the word 'boffins' and if it's good enough for them it's good enough for me.

(they also like variations on supercalifragilisticexpialidocious but that's just blasphemy)

From The Royal Society:

The economic potential of metalliferous sub-volcanic brines

Jon Blundy

Andrey Afanasyev

Brian Tattitch

Steve Sparks

Oleg Melnik

Ivan Utkin

and

Alison Rust

Published:30 June 2021

https://doi.org/10.1098/rsos.202192 

 

Abstract
The transition to a low-carbon economy will increase demand for a wide range of metals, notably copper, which is used extensively in power generation and in electric vehicles. Increased demand will require new, sustainable approaches to copper exploration and extraction. Conventional copper mining entails energy-intensive extraction of relatively low-grade ore from large open pits or underground mines and subsequent ore refining. Most copper derives ultimately from hot, hydrous magmatic fluids. Ore formation involves phase separation of these fluids to form copper-rich hypersaline liquids (or ‘brines') and subsequent precipitation of copper sulfides. Geophysical surveys of many volcanoes reveal electrically conductive bodies at around 2 km depth, consistent with lenses of brine hosted in porous rock. Building upon emerging concepts in crustal magmatism, we explore the potential of sub-volcanic brines as an in situ source of copper and other metals. Using hydrodynamic simulations, we show that 10 000 years of magma degassing can generate a Cu-rich brine lens containing up to 1.4 Mt Cu in a rock volume of a few km3 at approximately 2 km depth. Direct extraction of metal-rich brines represents a novel development in metal resource extraction that obviates the need for conventional mines, and generates geothermal power as a by-product.

 

1. Introduction
Our modern world is reliant on natural resources of metals, from steel for construction to rare earth elements for high-tech devices. As we transition from fossil fuel-dominated to more sustainable economies, demand for certain metals will rise dramatically. In a world powered by wind, sun and tides, for example, copper demand will increase more than fivefold, surpassing known global reserves well before 2100 [1,2]. The rise in demand for ‘critical metals’ (e.g. lithium, scandium, cobalt, rare earths) will be even greater [3]. As existing reserves become depleted and new deposits ever harder to find, it is unclear how the extra demand can be met; recycling alone will be insufficient [1].

Discovering natural mineral resources is, at heart, a geological problem. The majority of non-ferrous metals derive ultimately from igneous processes associated with magmatism. Non-ferrous metal ores can be viewed as extreme end-products of igneous geochemical cycles that begin in Earth's mantle and conclude with discharge of hot magmas and gases at the surface. Volcanic volatile phases are particularly efficient transporters of metals as evidenced by epithermal ore deposits and the chemistry of fumarole gases. Some active, subduction-related basaltic volcanoes discharge metal-rich gases with a time-averaged flux to the atmosphere of more than 10⁴ kg day⁻¹ of copper and zinc, along with a slew of other metals (e.g. silver, tungsten, indium, tin, lead, molybdenum) at fluxes of up to 1000 kg day⁻¹ [4]. This observation re-emphasizes the centrality of igneous processes to formation of mineral resources [5], and raises the possibility of recovering metals directly from modern volcanic fluids as an alternative to mining ancient solid ores. Here, we discuss the potential for in situ mining of hot, metalliferous volcanic fluids,¹ with a particular emphasis on copper, in light of recent developments in our understanding of the dynamics and architecture of crustal magmatic systems....

....MUCH MORE

It should be noted that this is The Royal Society's Open Science journal which doesn't have quite the heft or history of Proceedings "A".* And that, slim chance but possible—these boffins may be total loons.

As our tipster, Mining.com's Valentina Ruiz Leotaud notes: 

...There are risks to this proposal, though. The main ones are related to the technology that has to be used as the process involves drilling into rock at 2 kilometres depth and at temperatures of more than 450°C. On top of this, the extracted fluids are corrosive, which places limits on the types of drilling materials and they tend to dump their metal load in the well-bore, a problem known as ‘scaling.’....

*There is also Philosophical Transactions of the Royal Society whose back issues start in 1665.