Science in questions: a new programme on mineral resources

Hello, everyone. Hello, Marine and Laurène. Hi, Jean.

- Welcome back to Science in Questions. Today we're looking at subsurface resources. With the energy transition, some resources are coming under particular scrutiny. What are the critical minerals? How large are the reserves? How can we secure supplies? We'll explain everything, try to understand how these raw materials form, and look at alternatives to the exploitation of the subsurface. This programme promises to be a mine of information. SCIENCE IN QUESTIONS From flints to silicon chips, humans have always used subsurface mineral resources. Over time, the exploitation of these resources has even increased and diversified. Let's discuss the issues with our guest, Nicolas Charles.

- Hello.

- Doctor in Earth Sciences at BRGM, the French Geological Survey. As I said in the intro, with the energy transition, this exploitation is set to continue. How has it changed over the last 50 years? In the last 100 years, humans have exploited as many raw material resources as in the whole of Earth's history. This exponential consumption accompanies industrial revolutions: coal, oil and now, some specific substances for the energy transition. Could you explain this graph? It's from 1900 to 2010. What can we see on it? The consumption of mineral raw materials in different areas: primary metals, industrial minerals, building materials. And whatever the category, consumption has grown exponentially, particularly since World War Two. How will it evolve? What's the trend for coming years? Consumption will continue to grow exponentially. As you know, in the West, we are highly industrialized but developing countries need to grow too. This implies an ever-increasing consumption of minerals. The challenge will be to ensure they do not run out. Europe has established a list of 30 critical minerals. Could you give us some examples of minerals on this list and explain their role in the energy transition? Published by the European Union, this list of critical raw materials includes certain rocks, minerals and metals. For instance, tungsten. It is sought after for its resistance properties. It is used for abrasive items as well as armouring. It's a critical raw material as we are heavily dependent on outside-EU imports. Do you have another example? The rare earths, which we often hear about. These are the vitamins of new technologies, of digital technology. They are used to make permanent magnets and smartphone speakers. They're essential for miniaturized electronics. Flat screens owe their brilliant colours to them. And we also use them for other applications, particularly in electric vehicles. We hear about them in wind turbines too.

- Are there many in them?

- As I said earlier, they are permanent magnets. In slightly technical terms, it's neodymium and dysprosium. These are found in wind turbine magnets, especially offshore. The current technology uses rare earth elements

- for offshore wind turbines.

- Currently, Europe imports a large portion of mineral resources. Where do they come from? There are some mines in the European Union. But we are mainly reliant on imports, primarily from China, from whom we import the bulk of our critical raw materials. On this map, there are examples. For rare earths, we are heavily dependent. China has a virtual monopoly. This is also the case for tungsten. As well as titanium. And we can see that for lithium, we are heavily dependent on Latin America, on Chile. Europe's resources are limited. Simply look at this map and our raw material imports. Isn't cobalt very important - for car batteries?

- In electric mobility, which contributes to the energy transition, vehicle batteries have very specific metals, including cobalt, lithium and nickel. At present, over 70% of cobalt is produced in the Democratic Republic of Congo, in Central Africa. It tends to have a bad image. We'll come back to that. We like testing the public's knowledge with a mystery word. We chose the term "mineral resources". It seems simple but it isn't. Listen to the people we asked. THE MYSTERY WORD It's very hard to answer. "Mineral" brings to mind stone. So maybe... No, I don't know. Mineral resources are necessary for our future? Well, crystals... Otherwise, there are minerals in mines too. Mineral resources are resources found in the natural world which contain minerals. I would say things like coal, maybe. Lithium? And cobalt. They are in smartphones, batteries and so on. The difference between a metal and a mineral? I know the difference but I can't explain it. A mineral is a raw material and metal is produced from this raw material. That's how I see it. For instance, with iron ore you can produce iron, cast iron and steel. A mineral is... Oh! It makes me think of stones. It's anything that comes from rocks. I don't know the exact definition. Mineral water is water from the mountains. They mentioned cobalt, coal and crystals. They answered correctly on the whole, didn't they? Yes, absolutely. Aren't there two main types of mineral resources? There are two main types of mineral resources: energy mineral resources, which include coal as well as gas and oil. And geothermal energy, which is a subsurface energy resource. The other main type is non-energy mineral resources. These include metals, some industrial minerals and some rocks used for building and for roads. People still confuse minerals, ores, metals and rocks. What is the difference between an ore and a mineral? Our subsurface is composed of rocks. And these rocks are made up of constituents, known as minerals in geology, the building blocks of rock, and each mineral is made up of chemical elements that we find in the periodic table. Cobalt is a chemical element found in some types of minerals such as pentlandite. The names are exotic. Pentlandite can be found in a larger rock, with other minerals. And in terms of adaptation and extraction, when we talk about cobalt ore, in fact, this cobalt ore starts off as an aggregate of minerals, a mineralogical carrier, from which the metal is isolated and extracted. Isn't ore an economic term? Ore is a mineral resource that can be mined and processed for profit. Iron ore was explained earlier. You mine iron ore rich enough to be profitably mined. The iron is then extracted by a series of processes and used to make steel, cast iron and other alloys. Mineral resources are everything extracted from the subsurface? That's right. Water is another important mineral resource. In France, over 66% of the water we consume comes from underground, from groundwater aquifers. Are we surrounded by mineral resources? There are the rocks in front of you. Take this everyday object: the mobile phone. It is a mass of mineral raw materials. On average, there are 60 different elements. It contains metals, copper, gold, nickel, rare earth elements, and industrial minerals. These can be talc or carbonates. And its case is made of plastic, a derivative of petroleum.

- In this glass, the cameras...

- That's silica.

- Speakers.

- The cameras and speakers. The speakers contain magnets, which are an alloy of iron, of rare earths or boron. There are the plastic materials too. On our shirts, we have small buttons. They are probably plastic.

- I imagine so.

- We have jewellery and watches with metals or specific alloys. So we are surrounded by raw materials. And above us, there are insulating panels in which there is plaster. When you put it into words, we realize it is all around us. It is used in daily life. Let's look at the mineral resources available in Europe. At BRGM, you map these resources. Here's Science in Action. SCIENCE IN ACTION There are critical minerals needed for the energy transition beneath our feet. Yes, but we have to look beyond the ground beneath Cachan IUT, which is hosting our show, and consider Europe as a whole. Let's start with a 2016 map made from data collected by BRGM among others. On this map, what can we see? In the legend, we see cobalt, graphite, rare earth elements. Europe has many different minerals. Yes. This map was produced by the different European geological surveys. It is a topic we must approach on a Europe-wide scale. This is not a map of mines but a map of deposits. That is, the knowledge that in different places in Europe, there is a particular material. These are the critical raw materials identified by the European Union. As you can see, in northern Europe, there are nickel and chrome deposits. In Portugal, we can see tungsten deposits. These are found in France too. All these critical raw materials are found here as deposits that could be exploited one day. Let's discuss rare earths. You have worked on them. They are mainly found in northern Europe. They are the blue squares with small black dots.

- Why are they found there?

- The fact is humans have established borders but the subsurface has none, geologically speaking. This geology, as regards the nature of the rocks and their age, is the result of a life process of the Earth. The geologist sees it as dynamic. Most people believe it is static. But the geologist's aim is to portray this long-term history. The long term, as a result of processes, leads to the formation of certain raw materials, like rare earths, for which conditions are favourable. This is so for Scandinavia with the Scandinavian Shield, where there are typical deposits found only in these conditions.

- Why "shield"?

- "Shield" is essentially a generic term. It is used in geology because these are very ancient zones in terms of the rocks' age. These terrains have often resisted the ravages of time. And the term "shield" refers to this resistance. OK. You brought some rock samples. Do any contain rare earths? Absolutely. For example, this rock. It is from southern Greenland. The technical term for it is nepheline-syenite rock. Going back to what we said earlier, certain minerals make up this rock. Here you can see small pinkish red spots. This is a mineral known as dialite, a type of silicate. This sample is enriched with rare earths. To use the correct terms, this is a nepheline-syenite rock, which contains a mineral, dialite, and the whole forms a rare-earth ore. In absolute terms, do we have enough rare earths in Europe to meet our own needs? In terms of geological potential, there are rare earths in Europe. Most are known to exist in economic quantities. It depends on the stage of exploration. And there are some mines. We'd only need to open a mine to cover the bulk of the EU's current needs. Here, in the EU, there are no rare earth mines? Not at present. China remains the main producer. In continental Europe, in Karelia, there is a rare earths mine. It is in Russia. Rare earths are mined in Australia - and in the States.

- I'd like to look at how these maps are defined. In my research, I learned the word "gitology". What does it mean? Gitology is a historical term, a naturalist term. And a gitologist is an ore-deposit specialist. Gitology is a naturalist approach to describing a deposit. You describe the nature of the rock, the minerals contained in it as well as the deposit's geometry. Is it a vein? Is it along a fault? Is it dispersed? It is a purely descriptive report of an anomaly zone where there are interesting mineral resources to be found. Does anomaly mean a concentration of elements? Right, the term is "geochemical anomaly". Geochemistry, the Earth's chemical composition. What is exploited at present is essentially the surface layer, or Earth's crust. In this crust, thousands of measurements have given us the average concentration of each element known on Earth. When we are above this average, we speak of "enrichment" and we start to have a geochemical anomaly. This could potentially give rise to a deposit. In gitology, what defines a good deposit? To define a nice deposit, or rather, a good deposit, there are several criteria. There is the economic criterion. Is it profitable to mine? Is it rich? There is the notion of content. There is the amount, or tonnage. And in fact, it's the tonnage and value, or content, that is important for a deposit. Then there are the environmental and social aspects, which are more recent but increasingly important to consider. In concrete terms, when you think there might be something, how do you go about actually finding the deposit? The first step is to locate something. This involves mapping. And one of the first stages... As science is ever evolving, records already exist. So the first thing a mineral resource geologist does is consult the bibliography. Old maps, studies of specific zones where anomalies or minerals have been described. After studying the bibliography, you go into the field to perform analysis. This could be field observation, sampling then lab analysis.

- Do you take rock? Soil?

- It can be rock, stream sediment, soil samples too. The idea is that as the scientific investigation progresses, the geological knowledge is refined.

- It's an inquiry.

- Yes. Going back to rare earths, let's look at this map from one of your publications. These elements are considered when you look for veins or deposits. It's a geological map. What does it show? This document is typical of what geologists use to pinpoint the nature of the subsurface. This is a geological map of a rare earths deposit in Norway. The different colours indicate the different rock types. Depending on the types, there is a chance you will find the minerals making up these rocks. These minerals could contain rare earths. Depending on the quantities sampled and analysed from this map, we can identify the ore zones, that is, the richest zones, which could be used to produce rare earths. What you are doing is exploration.

- It isn't the same as exploitation.

- That's right. Exploitation means something has been identified which is economically interesting, environmentally and socially acceptable. First you have to know if it exists. That's the exploration phase. But exploration doesn't necessarily result in exploitation. The aim is to find a deposit. In most cases, particularly in pristine areas, there's a 1-in-100 chance we will.

- I see.

- The other important thing is, in the event that a deposit is actually found, from the exploration phase to the opening of a mine, it can take 10 to 20 years. If we want a supply of critical materials in Europe...

- We need to plan ahead.

- OK.

- Which we have failed to do so far.

- OK. The exploitation of subsurface resources has an impact on communities and the environment. What are these impacts? That's the question we put to the public. The first impact is obvious. It damages the landscape. Also, the large volumes of traffic cause pollution. These materials need to be processed, and this might involve using substances that aren't great for the environment. I can't think of any other impacts. One thing got me thinking... To clean the stones, they used tons of water. This polluted water was released into the environment, contaminating it, or something like that. For people, it's a calamity. I think there's a lack of regulation. There are no proper standards. In poor countries such as mine, there are people in the countryside who sleep in really deep holes to look for these minerals. It's a form of slavery, a form of hidden slavery. That's what it is. In France, efforts are made to ensure that it is ethical, unlike elsewhere. But as for the amount of energy used for it and the pollution, I think it's still quite problematic. I think we shy away from pollution. We prefer to entrust it to underdeveloped nations. Nicolas, without taking sides, are people close to the truth? It's a partial truth. We heard the negative impacts of the extractive industry. Like any other industry, it does have negative impacts. But the real challenge is to identify these impacts so as to better regulate them and eventually offset them. To offset this type of impact, you need a framework. And in mining areas, you can control this framework. But at present, as we said, the EU relies heavily on imports from far away, particularly China and some African countries, where regulations may exist but are often poorly applied. As end-users of smartphones, we are at the end of the production chain but at the other end, there's a mine or quarry. And the negative impacts of this mine or quarry, an impact on the landscape, pollution by hazardous materials, energy consumption, etc., are part of the process of manufacturing this product. We are partially responsible for the negative impacts. More often than not, consumers know very little about this whole value chain. It is extremely important to be aware of it. If we're not opening critical raw materials mines in Europe at present, is this chiefly due to our environmental concerns? Allow me to explain. In Europe, some countries are mining critical raw materials. This is the case in Scandinavia, for nickel and copper, where everything is properly regulated. Problems do arise, but everything is done to resolve them. This is hardly the case when it is a question of mining copper in China or rare earths in Bayan Obo. There are terrible impacts there. On the environment, water but also on the workers, both on their health and their social conditions. These people have extremely hard lives because there is not a strict regulatory framework for this type of mining.

- Relocating could also be a way to have mines that are cleaner and more respectful of workers. Yes. The idea... Like any industry, it needs a framework that is respected. If we want to increase the independence of Europe in terms of supply, we must not be hypocritical but honest. If we do not wish to delocalize the pollution and impacts yet still have these things, we must be logical. And this means possibly relocating to Europe, with a strict framework where there is a host of issues that must be known and respected.

- Speaking of which, the EC is discussing a responsible mining certification in order to ensure that the raw materials used for the energy transition come from environmentally sustainable mines. Could you tell us about this certification? Does it involve concrete things in terms of working conditions and resource management? The responsible mine is a concept. There are currently some 200 initiatives worldwide attempting to define the responsible mine concept. In simple terms, it means exploiting mineral resources based on all three pillars of sustainable development: economic, social: respect for people and for communities and environmental: respect for the environment. There are legislative frameworks covering these activities: the Environmental Code for quarries, the Mining Code for mines. There are legal constraints and best practices. These go beyond the legal requirements. And this is part of the responsible mine concept. Great. That's clearer. Thank you, Nicolas. With the energy transition, some minerals have become critical, such as lithium, cobalt and copper. For some of these resources, the EU depends on other countries for its supply. It is therefore essential to identify the raw materials available in Europe in order to reduce its dependence and diversify supplies. Now let's take a look at how mineral resources are formed. One of your BRGM colleagues will tell us all about it. Let's welcome her with our Team Spirit slot. TEAM SPIRIT Hello, Blandine Gourcerol. Welcome to the show.

- Hello.

- You're a research engineer and metallogenist at BRGM. I'm intrigued. I've not heard the term before. What is a metallogenist? A scientist who examines the enrichment processes of some minerals and ores in Earth's crust. We try to understand how these deposits form by looking at their age, the specific characteristics of the ground. We try to work out where other deposits are to be found. Blandine, I'll explain. You worked on the inventory of critical minerals listed by Europe, in particular lithium. What does your work on lithium entail exactly? There were two phases of work. The first was to understand on which minerals lithium could be found. There is a great variety of mineral carriers. Next we try to work out on which geological terrain, with which age and processes, we can find these minerals. Demand for lithium is set to increase significantly. Do we know by how much? Between 2019 and 2030, demand is estimated to increase sevenfold. From 2008 to 2019, it increased by 125%. Hence the need to find new deposits. Where is the lithium for phones and car batteries found? Most deposits are found, as we can see on the map, in Australia. Then there are deposits in South America too. And also in China. They are the three largest producers of lithium. Did you mention Australia first because it has the largest deposits? Not necessarily, but they have been the top lithium producers since 2012. Lithium is found in Europe, in France too.

- Where exactly?

- In Europe, some 600 lithium occurrences have been identified.

- 600 occurrences?

- 600 occurrences or anomalous points: with interesting quantities of lithium. Not necessarily economically, but interesting. There are also 27 deposits across the European Union. And we have tried, thanks to mathematical formulae, to build a model based on the metallogenic model. This favourability map attempts, from the scientific model and the occurrences identified, to reproduce the formula across the European Union. These red zones are zones where, preferentially, we are very confident lithium will be found. The yellow areas, a bit less and the green, much less. The white areas are areas where we do not really know. Are they the probabilities of finding interesting deposits? Or rather lithium occurrences. Not necessarily a deposit. With a deposit, there's an economic aspect. What is the lithium potential in France? Could the deposits meet demand? At present, yes. But demand is set to rise. The assessment done in 2018 is an overview or picture at a given time. It will be added to over time and as new discoveries are made. But lithium isn't found in its pure state in nature, is it?

- No.

- Is it always mixed with something?

- It always occurs in the mineral structure of a mineral. Here we have lepidolite and petalite. And this sample is zinnwaldite, a mica, which is enriched in lithium. It occurs in different forms. It is found in large crystals as well as in small crystals, as you can see here, these small black minerals. This clearly shows the tonnage. We will have a higher tonnage to extract an identical quantity than if we just had this. There are three main sources of lithium in the world. We have a diagram showing these three different sources. Could you tell us about them, on this diagram? There are three families. There are hard rocks. It's a slightly odd term. It's translated from the English! There are greisens, granites and pegmatites. This is what we will find. This is a greisen.

- This is a pegmatite. And a granite.

- Could you tell us what pegmatite is? It is an igneous vein body. In other words, it forms very long veins and over a long distance. Whereas granite is a pluton. It forms a mushroom shape in Earth's crust. Does it depend on the rate at which the magma cools when it rises in the crust?

- Yes. And on the encasing rock. In the encasing rock for pegmatites, it's possible that veins will form. PROPOS INAUDIBLE This is not the case for pluton as such. Going back to the diagram, on the left, what can we see in the crust?

- Is the red the rising magma?

- That's right. There are two yellow stars in the greisen. This is where we will find mineralizations. And in the granite, which is lower in the crust. Then we have the pegmatites next to the other yellow star. And these pegmatites are in grey.

- Those are the hard rocks?

- Yes. What are the other sources of lithium? Lithium salar brines. You can see one in the centre of the diagram.

- The small blue lake?

- Exactly. With the little star. In fact, they are evaporites and they occur in basins, arid and semi-arid basins, in very specific areas. They can be found in China as well as Latin America, in a specific area known as the Lithium Triangle, between Bolivia, Argentina and Chile. They're highly concentrated waters.

- Is that correct?

- Yes. It is a structurally active basin. That is, hydrothermal heat circulates in the basin. How do the concentrated lakes form? Where does it come from? The lithium comes from underlying rocks that are leached by hydrothermal fluids or even magmatic fluids, which rise to the surface and, with evaporation, the lithium increases as it does not evaporate. The water is condensed and the lithium concentrates on the lake bottom. Are salars like salt flats? Absolutely. That's right. And there is a third and final source of lithium: geothermal water. Let's look at the diagram. The far right of the diagram. How does this lithium form? Allow me to correct you. These are unconventional sources. These sources include sea water. Lithium is present in small quantities but nonetheless present. Another source is lithium-bearing clay. Then there is geothermal water. This is shown here, on this diagram. What we can see is... A good example is the Rhine Graben between France and Germany, where a basin is drained by large faulted structures. And there is a circulation of fluids that allow the leaching of rocks and which will cause a lithium-rich solution to rise. Why is it unconventional? The terms "conventional" and "unconventional" were coined in the very early days of lithium prospection to describe the types of extraction processes. The majority of extraction processes are still in the pilot phase for water and clays. We are seeing more and more interesting phases. They are economically viable and could be implemented. But historically, there was this distinction. Does a better understanding of the origins of lithium deposits help you know where to look? Yes, especially for geothermal water. We have to understand what the encasing rocks are, their ages, in order to have an idea of the primary enrichment of these rocks in lithium before a fluid can leach these rocks and concentrate the lithium associated with them. In what form is lithium found in France? We have geothermal water and very interesting hard rocks, such as this rock here. Is that from mainland France? Yes, from the Massif Central. Are we capable in France of exploiting and recovering lithium? Yes. There are some interesting deposits that are being assessed for resources and reserves. That was very clear. Given the environmental and supply issues, we could limit the exploitation of resources. But how? We asked members of the public to give us a few solutions. Here they are. I don't really have an answer. Otherwise I would be Minister for the Environment or for Living Better! Everyone should be careful in using these resources. We discussed rare ores earlier. There's no need to change mobiles every year, like some people do. Consume less? I hope it is possible because the planet is in danger. Limit their use, maybe. Some sectors are less important than others. Medicine or engineering could be favoured over other sectors. But how do you decide which is important? There are so many unknowns. We could try to recycle as much as possible, reuse the resources already extracted, which have already been fully used. There's a lot of waste there. Recycle like crazy, recycle everything, including smartphones and so on. For the time being, I recycle at home. I give my old phones to my kids to use as cameras. But society as a whole would have to change, all over the world. There'll be many disasters before that happens though. That woman mentioned recycling. Is it one of the answers? It's one of the preferred solutions. But contrary to popular belief, the demand for raw materials is such in the current economic model and in development, that recycling will never fully cover this demand. That's obvious, so in other words, we should favour recycling, increase it, but mining and quarrying are still necessary. It simply eases supply tensions. It will never replace... It depends on the substance. There are some substances that are heavily recycled. For instance, in France, some 90% of lead is recycled and this meets about 60% of demand. In France, do recycling channels exist? Do we recycle some elements well? In France, we recycle glass very well. To have a good recycling rate, there are several factors. Firstly, the collection system. End products are collected, those we consumers use. That's the first thing. Secondly, recycling must be considered upstream, when products are designed. This is eco-design. As for metals, if you look at rare earths, we currently recycle less than 1% of rare earths. The main reason being that we use them in very small quantities in components, and so they are dispersed. It would cost more to recycle the rare earths in our products than to continue to use these products differently.

- It's an issue of cost.

- Absolutely. So using some materials less in the design of items could solve...

- It's a solution.

- Or knowing better where they will be located in electronic components. With recycling, there are primary resources, what we extract in mines. Then what are known as urban mines. These are secondary products, everyday objects, which in turn become ores. This leads to treatment processes similar to the extraction processes in the metal industry. But to encourage these treatments, you need well-designed components so that the elements to be recycled can be easily separated. In the vox pop people mentioned restraint, digital technology too. We've discussed the energy transition. We've no choice. We know there are materials we'll need a lot of in the future. As I said at the start of the programme, the consumption of raw materials accompanies industrial revolutions. We had coal, we had oil. Now we have critical, strategic, rare metals. We hear all kinds of terms. As regards electric mobility, a key element of the energy transition and decarbonisation, this will involve increased use, as Blandine said, of lithium, nickel, cobalt, etc. So in fact, the change, at present, in the energy transition, is increased consumption of these raw materials. You mentioned restraint. I liked what the interviewee said. There's no need to change mobile phones every year.

- For instance.

- If we reduce car usage, we will need fewer batteries. But that requires a societal change.

- It's something else entirely.

- Yes. This may sound blunt but the aim is to inform people: these concerns are prevalent in developed countries but I cannot imagine forbidding an Indian or Chinese person: "You cannot own a car. "It's for the good of the planet." For instance. It's complicated. It's a common asset. There is some hypocrisy in the debate on mineral resources. We would like to be more virtuous by closing mines and quarries. But with digital technology, our consumption of raw materials has skyrocketed. There is a lot of talk about going paperless but there are physical things behind this, data centres, storage services, etc. All of that is raw materials. Which we don't actually see. That's clear. Let's hope we'll move in the right direction. We're going to change topics and look at your careers. Here's In the Wings. IN THE WINGS Marine, I believe geology is something that is in a person's blood. It is in Nicolas's! Your passion for rocks and minerals runs in the family. Your father and uncle took you on geological jaunts as a child. What did you do on them? I'm a bit like Obelix only not quite as big! We'd go out in the Limousin, where I have family roots, to collect minerals and rocks. In Charente-Maritime too. But that was for fossils. From a young age, when I was four or five. I even learned to count with pebbles. Logically, you decided to study earth and life sciences and did a doctorate that took you 8,000 km away, to China. Why did you go so far away? The subject took me there. After my master's, I was offered the subject, a partnership between Orleans University and Beijing Science Academy. The subject was about China and involved a lot of fieldwork. I spent one to two months over there every year. In particular in an area by the Great Wall close to Beijing, and also in Shandong, a peninsula south of Korea, but still in China. I spent a fair amount of time there. What did you take away from the experience? When I started my PhD, I was twenty or so. It was the first time I'd left the cow pastures! Moving to the other side of the world was a culture shock in every sense of the term, positive and negative. But it was quite an experience. And it was also the discovery of a new scientific environment. In terms of geology, it was a new theme. As regards methodology too, I learned new techniques. And I met many very different people. I was able to join a multidisciplinary team. I gained a lot from it. An objective approach, how to better grasp a subject. Blandine, your passion for geology began in secondary school. What triggered your interest? The trigger was a field trip to the volcanoes of the Auvergne with our teacher who'd taken us there. It was a really pleasurable experience. I wasn't sure I wanted to make a career of it. But I realized it was a passion that I had had for a while and that had guided me from the start. Nicolas, you have two types of work day. Days at the office reading articles and writing reports. And days in the field, at conferences, training others. We have photos of you in the field.

- What do you prefer in your work?

- Nice office! Most definitely, I prefer that office! That was in Malawi. It was a geological mapping expedition. The aim is to compile a document useful for all sorts of things in everyday life: locating resources, better management of natural hazards, finding water resources. It affects our daily lives. Here I am with a Malawian counterpart doing a field survey. We identify and describe the different rocks, take measurements, see how the rocks are positioned and arranged, in order to build a geological map. Even if the map is in 2D, the geologist has a 3D view. You can do this on foot, by car... That was in a dugout in Congo-Brazzaville. It was another geological mapping expedition. Blandine, you switch between the office and assignments overseas too. But you now spend less time in the field. Do you miss it? Yes. We do this job out of a passion for fieldwork and desire to be outdoors as much as possible. My career has meant I am more involved in project management at a European level, with multiple partners. So I spend less time in the field and a bit more in meetings with our many European partners. What do you like about fieldwork? Well, the contact with rocks, when we look at all the minerals in a particular rock. That's me in Canada. I spent my summer examining the small rock I am on. And it was magical because there were a number of different animals who spent their days with us. You have a story for us about that trip. You met some Inuit artists in northern Canada. Absolutely. I got the opportunity to work each summer while doing my PhD, for an exploration company. And where we were working, there was a rock, which the Inuit call soapstone. The scientific term is komatiite. It is a type of rock whose nature means it can be easily carved. It's very easy to carve. And the Inuit showed us their work by working directly on the rocks on the site. It was a fantastic and very rewarding encounter. Nicolas, you have quite a few anecdotes too. The list reads like an adventure film! You stayed in hotel opposite a drug hub in Haiti, you encountered a leopard in Malawi.

- Our very own Indiana Jones! Right! And you were even chased by a hippo in Congo. Could you tell us more? That was in Arabia. There are no hippos there! But in the Congo, I was on a small boat with my Congolese counterpart and a guide. We stopped by every outcrop, where you can see rocks, along the river. At one point, there were steeply sloping cassava fields. We heard this cry... And wondered what it was. You rarely see a European and two Congolese on a boat in the middle of nowhere. We thought someone was greeting us, but no. There was splashing in the water. It was a hippopotamus. The hippopotamus is one of Africa's most dangerous animals. That's the only time I thought, "Yikes!" So we went around it. And it all ended well. We saw the farmer again, waiting for us in the next village. We talked and he told us it was a hippopotamus area and that the village children were taught how to recognize hippopotamus tracks. But not only do they swim fast, they also run fast. We're going to end with another animal story. Blandine, you've encountered many animals too. Here are some photos. What's this animal? An arctic fox. It is the only type of fox to be active during the day. It changes colour. Its fur is white in winter and turns brown for the summer. Have you ever had any incidents with animals? Not personally. But I have experienced similar things, such as being chased by packs of wolves or bears.

- What great stories.

- BRGM is a real adventure! Before we go, let's discover our guests' hidden passions in Firm Favourites. FIRM FAVOURITES Our two guests are all-rounders. Sticking to the theme of geology, Nicolas, you carve stone but not only. You make watercolours, play piano and write popular science books. Where do you find the energy and the time? I'm driven by passion. And also it enables me to meet a very diverse range of people. That's rewarding. And I find it interesting to inspire people. That's me at a book signing event. It also means, particularly in lectures, I can share my knowledge. I think that's important especially as the geosciences are not well known by the public and yet they have a direct impact on everyday life. Does the creative side help you see things differently when you work on a mineral? A geologist is essentially a naturalist. We describe a lot, we observe, and we can be geopoetic at times! We often tend to say: "Put 3 geologists on an outcrop, and you'll have 3 interpretations."

- Maybe even 10!

- But yes, you need to know how to step back. And in geology, what is interesting, when you look at what's happening in society and so on, is that the geologist has an understanding of the long term as well as of space. We're multiscale. We can observe a mineral of this size but also reconstruct, from small outcrops, the history of a mountain chain. That teaches you to be extremely humble as regards our planet and our environment. Blandine, you enjoy gardening. You have 200 rose bushes. Why roses especially? Because each has its own personality. They all have a different colour. You approach each in a different way too. It is a bit as if my naturalist side shows in gardening. Nature is part of our way of thinking about the world. It also enables us to put time in perspective. And time becomes a bit longer in the garden. You work in seasons not all at once, to have something immediately. Do you make bouquets? Do you take orders? Yes, for the garden. It's possible. That's all for Science in Questions. Thank you for this exploration of the subsurface and its riches. It was pure gold. I thought a pun was in order! Thanks for watching. See you soon for more scientific curiosities. Goodbye for now.