The final frontier: could biomining be the future of resource extraction in space?

As technological sophistication improves and financial investments grow, there is increasing optimism across a number of sectors that humanity is closer than ever to establishing settlements and infrastructure among the stars.

With well-established groups such as NASA providing the financial backing and technical expertise, and private companies SpaceX and Blue Origin driving innovation with the relentlessness of a for-profit enterprise, the concept of space mining in particular moves ever farther from the realm of science fiction and towards a reality for the future of humanity.

This is no surprise considering the, literal, astronomical financial rewards on offer. The oft-quoted figure, put forward by CNBC, is that the Asteroid Belt alone contains enough mineral wealth to give every person on Earth $100bn. With commodities such as rare earths and platinum groups metals in higher demand than ever before, there is every reason to think that, in the future, many of humanity’s mineral needs could be met by mining operations beyond Earth.

Yet many of the world’s scientific communities are targeting projects closer to home, in order to demonstrate the effectiveness of technological innovation and the financial viability of interstellar operations. The Moon remains the centrepiece of humanity’s space efforts and research from the University of Edinburgh, tested on the International Space Station (ISS), offers a new form of mining that could be deployed on the Moon.

The university’s work centred on bacteria and how it can be used to eat away at mineral deposits to reveal precious commodities. This process of “biomining” has now been proven to be effective in zero-gravity environments, raising hope for a new type of resource extraction to propel humanity to the stars.

Biomining itself is not a new phenomenon, but the unique environment of space, namely the lack of gravity, poses challenges for a process which relies on the dissolution of a material in a fluid.

“In microgravity, fluids cannot move around very easily,” explains Professor Charles Cockell, an astrobiologist at the University of Edinburgh and one of the minds behind the biomining project. “There's no convection or sedimentation that you get on the Earth. If you've got microbes or bits of rock in a tank, they’ll tend to settle to the bottom, and that doesn't happen in space, so we might expect that that change in fluid behaviour would affect the way in which the microbes mine the rocks and release elements.

“That's what we really wanted to test, and in the process to also demonstrate the process [and] general principle of biomining beyond the Earth and carrying out mining on other planets.”

Cockell notes that in terms of demonstrating the viability of the technology, the project had been a success. Over a ten-year period of research, matchbox-sized mining devices were developed at the UK Centre for Astrobiology at the university and eighteen of them were transported to the ISS aboard a SpaceX rocket launched in July 2019.

Researchers then submerged basalt in the miniature reactors, and the erosion of the non-precious mineral was so intense that they concluded that using the bacteria to mine on the Moon or Mars could improve the rate of recovery of precious minerals by around 400%.

“There are other ways of doing mining using conventional techniques - leaching rocks, using chemicals - but the nice thing about microbes is that they use very little energy, they're very efficient, and they don't require toxic compounds,” says Cockell, highlighting another of the process’s benefits. “Microbes reproduce on their own, you just give them some food, so they are a very energy efficient and highly specific way of getting elements out of rocks.”

What could be most impressive about the project, however, is that many of the technological processes behind it are not new at all, but adaptations of mining operations already used on the Earth.

“What we are doing is just transplanting and adapting something that we know works on the Earth,” explains Cockell. “About 35% of the world's copper is extracted from rocks using microbes, so biomining is widely used on the Earth. And the reason for doing it in space is because wherever you are, whether you're on the Moon or Mars, you want to mine minerals, at least if you want to establish an independent presence.

“You don't want to have the massive energy costs of having to launch things from the Earth [and] take them somewhere else; you ought to be able to get them locally.”

This biomining process has been used extensively in Chile, which is responsible for around one-third of the world’s copper production. Projects such as the Lo Aguirre mine near Santiago, which produced 14,000 tonnes of copper a year between its commissioning in 1980 and its closure in 2002, demonstrated the effectiveness of biomining on an industrial scale, and influenced later acid leaching projects in the country.

For instance, in 1994, the Quebrada Blanca and Cerro Colorado mines were among the first to use bioleaching exclusively to extract valuable minerals from excavated ore bodies.

The challenge for Cockell and his team, therefore, was not one of inventing a new technological process, but demonstrating that an existing one can be effectively transplanted from the Earth to space, and adapted to function within the environmental constraints of the area.

“One of the things I've always emphasised with this experiment [is that] our interest is in demonstrating mining in other environments to support a human presence there,” he says.

“So if you're on the Moon, you want to be able to create a self-sustaining presence and have a civilisation anyway, you've got to be able to mine stuff out of rock. If you want to build a settlement long-term on the Moon that doesn't depend upon the Earth, you need to be mining material.”

Yet Cockell was also ready to point out that while the experiment was a success, this does not mean that the world’s mining companies ought to set off for the Asteroid Belt tomorrow, pickaxes and acid samples in hand.

“It was a little thing, about 10cm long by 4cm or 5cm wide and the apparatus is very small,” he said of the reactors themselves. “And it is of course a scientific experiment, not a scaled-up biomining experiment. What we were trying to do is address scientific questions and also demonstrate the principle of it.

“If you wanted to do it on a commercial scale, you would want a much bigger reactor, you might want to introduce stirring and, of course, post-processing. We showed that the elements could be leached from the rock, [but] eventually you've got to remove them from the liquid and purify them so there are other steps as well.”

This dichotomy between small-scale scientific demonstration and large-scale industrial process is not uncommon in the mining industry, but takes on a new dynamic with regard to space mining in particular, where scientific and commercial projects are not necessarily aligned. He pointed to the difference between NASA, whose status as a taxpayer-funded organisation makes it inherently cautious and risk-averse, and SpaceX, which as a private company has greater leeway to invest in riskier and more financially lucrative projects. 

In general terms, the scientific community has an interest in using the Moon as a platform for future research into human space exploration, while private companies are driven more directly to ends which are profitable, in this case space mining.

However, there is an optimistic viewpoint that despite these differences, the two sides will be able to cooperate, due to their shared long-term vision of expanding the human presence beyond Earth. Cockell pointed towards relationships between public and private companies, such as NASA investing $3.1bn into SpaceX to fund its Crew Dragon craft as a replacement for the Space Shuttle, as examples of how the technological expertise and financial might of one might be aligned with the ambitious and relentless expansion of the other.

He went on to point out that many of the challenges associated with space mining will cease to be technological in nature, and more based on logistics and financing. With the technology proven to be effective, it falls on companies and organisations to effectively allocate resources to scale up the work done by teams such as Cockell’s.

“People are thinking about mining beyond the Earth, there are groups of economists and engineers who think about these things,” he concluded. “It’s really a task for them to think about how this would be implemented, or what would be the best way of doing it.

“This [research] is definitely a first step, but it's an exciting first step I think, as it shows that we've demonstrated that biomining is possible in space. The next steps would be to scale this up, to try to do it on a larger-scale space station and involve not so much scientists like us but involve economists and engineers who then need to think about how they would do this on a larger scale.”