There's a saying amongst miners
that if it can't be grown, it must be mined.
And this is absolutely true for the metals
and the materials that we need for modern lifestyles.
Demand for metals, for all kinds of metals
is rising very strongly.
Simply because economies are reopening
from the nadir of Covid-19.
That really boosts demand for all sorts of things.
Your household stuff,
your refrigerators, including big things
like if we are building a new bridge
or building a new highway,
they all need metals.
So demand for metals is really rising strongly.
Nickel mining in particular has been increasing in demand
since the early 2000s,
largely due to China's economic boom.
And the rise of electric vehicles
means nickel consumption is only set to grow.
Meeting demand for nickel
means that nickel mining needs to upscale
in many countries around the world
and it means expanding nickel mines
using traditional methods of strip mining,
which will have an effect environmentally.
And so with increasing demand
comes greater responsibility
to minimize the damage caused by mining,
and to search for sustainable options.
For the past 30 years, researchers worldwide
have been pursuing a more radical
and eco-friendly technology called agromining.
Also known as phytomining.
Growing crops of plants that absorb and store metal
from the soil, that can then be harvested.
We have already worked with zinc,
with the rare earth elements, which are very important
for recent technologies.
And it's also possible to recover cobalt
from this technology.
But despite the success of this research,
does agromining stand a chance
against the massive scale of conventional mining?
And it can convince a legacy industry to change its ways?
I think they are committed.
I think they have really good intentions
to mine their products in a sustainable way,
but ultimately, I think mining is a dirty business.
While mining is necessary and has many positive benefits,
must say that,
it does have many negative aspects,
and especially the impacts on the environment.
Mine wastes are large sort of volume
of waste material generated by mining
and these can be in liquid form
and they can contain very acidic waters
that contain a lot of metals and metalloids that are toxic.
And so when those get out into the water environment,
they can contaminate land and water,
kill plants, reduce biodiversity.
Mining is also responsible for air pollution,
from the dust generated during extraction
and the roasting and burning of ores,
which can lead to acid rain
as well as contribute to emissions.
Surface mining also causes deforestation
as trees are cleared to make space for mining sites.
Nickel mining in particular presents problems
due to its emissions.
To the extent that in 2020, Elon Musk put out a call
for ways to meet nickel demand sustainably.
You may think steel is the most polluting metal
when it comes to CO2 emissions,
but actually nickel has the highest CO2 emission intensity
of all metals.
CO2 emissions per ton of metal
for the nickel production on average
is about 18 tons of CO2 per ton of metal.
Nickel processing, smelting and refining
also has the highest CO2 emissions of mined metals.
I would say probably the actual extraction of minerals
and metals and materials,
does the most damage.
If you have a deposit
that maybe contains 1% copper these days,
that means 90% is waste material.
And so you have to clear that
to get to the 1% copper that you need.
So it's probably the extraction phase
that generates the most damage,
and the most waste, which therefore needs to be managed.
The mining industry is estimated to make up
4% to 7% of greenhouse gas emissions worldwide.
But mining companies are facing increased scrutiny
from investors and regulators
who want them to pay attention to environmental issues,
and commit to carbon reduction targets.
The nickel industry is making improvements
to make mining more environmentally friendly.
For example, some plants have been using renewable energy
hybrid systems as a fuel source.
And Indonesia, they are the largest producer in the world,
they also set up emission targets
for the next decade.
But the industry as a whole is slow
compared to other industries.
But the global demand for metals
needed by modern society,
means destructive mining practices will continue,
if not expand in the future.
But in the east of France,
there's a group of scientists
hoping to speed up the pace of change.
Dr. Antony van der Ent is visiting
from the University of Queensland.
For the past 15 years, he's been investigating
the power of plants to harvest minerals
and metals from the soil.
And along with scientists from across Europe and Asia,
he's been developing a process called agromining.
So agromining is the process of growing
hyperaccumulator plants on an agricultural scale,
in a type of agricultural operation.
And not to produce something that you can eat, food crop,
but to harvest the metal from their biomass.
So hyperaccumulators are a rare group of plants
that have the unusual ability
to accumulate very high concentrations
of particular metals into their living shoots,
so into their leaves.
We know of about 700 of them
that occur all around the world.
And most of them are known for nickel, 500 or so of them.
We know hyperaccumulators for a whole range
of different metals,
including thallium and zinc,
and copper, cobalt, manganese.
But we keep discovering more of these plants
wherever we do research.
So it is about 350,000 plant species around the world,
and we think there are more hyperaccumulators
that are awaiting discovery.
A nickel hyperaccumulator plant takes up the metal
present in the soil through its roots.
It then stores it in the skin of its leaves or biomass.
After the plants are harvested, this biomass is dried
and incinerated.
The ash created by burning the plants
is then ready to be processed
to create a bio ore,
from which the nickel can be recovered.
Chemical engineering professor, Marie-Odile Simonnot,
uses a form of hydrometallurgy
to extract the nickel from the bio ore.
So here is the ash,
and the ash is very rich in nickel.
It contains up to 20% of nickel,
that is more than any ore on the Earth.
Then nickel is extracted from the ash.
The ash is first washed.
And then nickel is extracted by an acid
at a high temperature.
And this solution is filtered to remove the ash
and recover the solution containing nickel.
And finally, we have a precipitation stage
in which nickel is precipitated
in the form of a nickel salt for instance.
But we could do any kind of nickel compound.
It could possibly function for many other metals,
depending on we have plants able to accumulate the metals
and develop the methods to recover the metals
from the plants.
But the first step is to have the plants.
Nearby, at Econick's experimental farm,
professor Guillaume Echevarria
and his team grow new varieties
of hyperaccumulator plants
to be trialed around the world.
So here we are in the Econick experimental farm.
This is where we prepare seedlings and plants
to transplant into contaminated soils.
But also this is where we try to breed new varieties
of hyperaccumulators to grow in Greece
and other countries.
This is Sedum plumbizincicola,
so it bears the name of the metals
where it was found.
This is a zinc and cadmium hyperaccumulator,
so we mostly use it to decontaminate
contaminated soils.
This is Pelargonium capitatum.
And this is a lead hyperaccumulator,
again, to decontaminate polluted soils.
Here we have the local zinc and cadmium hyperaccumulator,
Noccaea caerulescens,
which is endemic from Western Europe.
Guillaume and his team carefully breed
and select plants to improve nickel extraction from the soil
with the goal to double the amount of metal
a plant can absorb and store.
So this plant
is the most efficient nickel hyperaccumulator
we have in Europe.
So leaves can contain up to 4% of nickel, dry weight.
That means when we ash them,
we can reach 29, 30%
of nickel in the ashes.
That's the record.
While incinerating the plants uses energy,
the team's tests have found the overall agromining process
uses significantly less energy
than conventional mining procedures.
These highly efficient hyperaccumulator plants
are also able to grow in soil which is ultramafic,
containing high levels of metals
that can be naturally occurring through rocks
or contamination from human activities,
including mining.
Traditional strip mining would also take place
on land that has the very highest grade of nickel.
In contrast, agromining can take place on soils
that are much lower in nickel,
which are very widespread.
So for example, in Indonesia,
the island of Sulawesi has over 15,000 square kilometers
of ultramafic soils.
Now perhaps only a small percentage of that
is suitable for agromining,
but that still represents a huge area
that could be developed.
Now the impact from agromining
is comparable to normal, other types of agriculture.
So it has a very low environmental footprint.
That contrasts quite strongly to strip mining
in that respect.
Ultramafic soils usually lack
the essential nutrients needed to grow most crops,
so they're abandoned by conventional agriculture.
One of the more immediate benefits
of hyperaccumulator plants
is that they can help to clean up contaminated soils,
provided their roots can reach the toxins.
Installing the hyperaccumulator plants
on this kind of material
is a kind of nature based solution,
which allows the vegetation
and the soil fertility to grow quicker
than if you apply conventional methods
of soil rehabilitation.
Agromining, especially in the case of nickel,
takes place in regions that have poor soils
because of their lack of fertility.
It can really be an opportunity for small farmers
to earn a living.
Then of course, it's very interesting
to provide both renewable energy opportunities
and also the production of a very targeted mineral
or even metallurgical industry.
We think there's a lot of potential
for agromining to be undertaken by local communities,
particularly in the Philippines and Indonesia.
Where local communities could grow hyperaccumulator plants
much like any other crop, on ultramafic soils.
Those soils, ultramafic soils
are typically not suitable for normal food crops
because they're highly infertile
and because the nickel in the soil is toxic.
So over a time that the phytomining takes place,
which we think is between 20 and 30 years,
the soil quality is improved
by increasing the fertility
and by decreasing the nickel that is in the soil overtime,
so at the end of the phytomining or agromining process,
the soil is actually suitable potentially
for normal food crops.
There have already been successful commercial trials
in Europe for smaller scale farming.
But the future of agromining
depends on collaboration with commercial mining companies.
We don't think that agromining
can replace traditional mining of nickel entirely.
Traditional mining takes place at huge scale,
it has very high efficiency of processing,
enormous quantities of ore,
talking kilotons of nickel in a year's time
for a single mine.
So we see this as a supplementary form
of producing nickel
with a very low environmental impact
alongside the traditional mining
that needs to supply nickel at scale.
So typically, on a mine lease,
only a small part of the whole site will be mined,
but as a much larger area that still has nickel in the soil
which is below the current grade for normal processing.
So in that halo around the mining operation,
you could also develop agromining
as a complementary technique
alongside the traditional mining.
The challenge of course
is to make an economic business case
where the scale at which this could happen
is large enough and the product, the bio ore,
valuable enough to make it worth the effort.
Their technology does look really cool,
really appealing,
but they are all at very early stage.
They have not reached to mass production level.
For example, for nickel,
we all know that we are going to need a lot more nickel
in the future,
to be able to achieve the climate goals
pledged by automakers, governments
and just like the world in general,
to build a better future.
If those technologies are cool, are really valid
and legit, they need to really kind of work out
mass production.
If they get endorsements from those big automakers
and OEM's, then that to me
is a big thing.
That means they are on the map,
that will attract more investors.
It's taken a few years for agromining
to find its place
and to be fully validated.
The main challenge has been to essentially
get it from a scientific idea
to test it in the lab scale and in the greenhouse
and then to bring it to the fields.
Many other species still remain untested
even though we think there's a lot of potential,
not just for nickel
but also for other elements that can be agromined,
including cobalt and manganese
and zinc and selenium.
A lot of that has to do with essentially
finding the right species,
and then finding funding to set up trials,
both in the lab
and then upgrade it to the field.
Agromining is of course one of the different tools
we will need in the future,
besides circular economy, recycling
and of course, exploiting new resources.
So I think in the future,
it would be great that we can benefit
from this knowledge that has been acquired
for decades now.
And really use the potential of these hyperaccumulator crops
to really produce the tremendous amounts
of strategic metals
that we will need for the ecological transition.
I think for environmentalists,
they need to be aware of that.
It's a very delicate balancing act for miners.
On the one hand, they need to produce the products
we actually need in the future and a lot of them.
But on the other hand, they also need to be aware
of the environmental impact.
So governments are very interested
in these types of techniques
to extract metals and reduce toxicity
and reduce the environmental impacts.
It very much fits in the circular economy theme
of putting materials back into the system
and reusing them,
rather than just generating waste
or having to dig up new materials
and I think we'll see much more of it
in the years to come.