The mineral resources inventory: answers to your questions - FAQ

On the occasion of the Ecological Planning Council in September 2023, the French President announced that the Inventory of France's Subsurface Mineral Resources would be updated. This decision was taken in preparation for the entry into force of the Critical Metals Directive CRM Act in May 2024, and was in line with the political impetus provided by the conclusions of the "Varin Report", submitted to the French government in 2022.

Identifying the most likely areas in which mineral resources may be found

The aim of this initiative is to identify areas in the subsurface that are likely to harbour mineral resources of interest. It is the first stage, known as strategic exploration, in an approach designed to encourage the emergence of viable, responsible mining projects that meet the expectations of the various stakeholders.

The approach involves collecting and combining different types of data (geological, geophysical and geochemical) to identify new mineral targets, using innovative technologies such as multi-method geophysics and artificial intelligence.

The work has been entrusted by the Government to BRGM, which is leading the project. The objectives and outlines of the project were drawn up in close collaboration with public authorities.

Regional projects

Five regional areas of interest have been identified and will be covered by data acquisition campaigns. The results, once interpreted, will identify the most favourable areas for the presence of deep deposits.

The project, launched in 2025 for an initial period of 5 years, will cost a total of €53 million (excluding VAT) and will be funded as part of France 2030 by the Secretary General for Investment (SGPI) via the French National Research Agency, ANR. To achieve this, BRGM will be relying heavily on its dedicated subsidiary, BRGM Explore, as well as specialist subcontractors and scientific partnerships.

The mineral resources inventory launched in 2025 is in part an update of the previous reference, an inventory carried out between 1970 and 1995 by BRGM in mainland France and French Guiana.

Potentiel minier en métaux de base en France hexagonale. L’inventaire des ressources minérales l’actualisera et le complétera.

© BRGM

This inventory is now obsolete, for a number of reasons.

1. There are a number of areas that have not been studied

More than 30% of the "Potential discovery areas" were not studied during the previous campaign, due to the existence at the time of exclusive exploration permits (PER - Permis Exclusifs de Recherche) held by private operators in these areas.

2. Developments in exploration techniques and corresponding analyses

Mineral exploration techniques have evolved considerably in recent years, having benefitted from major technological advances since the 1980s:

• For example, the previous inventory lacked large-scale geophysical survey techniques/methods that enable us to gain a better understanding of the nature and 3D geometry of subsurface structures and heterogeneities, and above all to probe the subsurface at greater depths (more than 1 km) where the previous inventory remained close to the surface (less than 200m).
• Analytical techniques in geochemistry have advanced considerably. As a result, the information collected during the first inventory often differs greatly from one sector to another, making it difficult to harmonise the data across the whole of mainland France. Furthermore, technological advances have helped to Exclusives detect these minerals when they are present with lower concentrations than was previously possible.

The various techniques (e.g. geochemistry, geophysics, geology) should make it possible to identify deposits that are "hidden under a cover" (and that are therefore not detectable on the surface) and have never been identified in the past, or deep-lying extensions of previously identified deposits. The future inventory will improve and complete our knowledge.

3. A limited range of mineral substances, excluding certain raw materials that are now considered to be of strategic interest

Finally, the previous inventory focused on certain substances (22 in total) that corresponded to the priorities of the time. Many other mineral substances, which are now regarded as critical and strategic, were neither searched for systematically nor analysed (lithium, tantalum, caesium, gallium, germanium, hafnium, etc.), or their detection thresholds were far too high to enable geochemical anomalies to be identified. Around fifty substances will be analysed as part of this new inventory.

The aim of updating the inventory of mineral resources is to help secure supplies of mineral resources in France and Europe, at a time when these raw materials are becoming increasingly necessary and strategically important, particularly for the energy transition. Indeed, the transition to low-carbon energies implies a significant use of various metals.

Added to this is the digital transition, which is also helping to increase demand for mineral resources.

To meet our needs for critical and strategic metals, Europe and France can strive to achieve three objectives:

1. As a priority, we need to think about how we use our raw materials and implement consumption-reducing measures and eco-design measures (saving materials) to keep our need for raw materials under control.
2. Secondly, we need to develop recycling sectors to extract some of the materials we need from end-of-life objects and industrial waste. This means developing a recycling industry, but also developing economic models and organising the establishment of these sectors.
3. These first two goals are not enough to meet the challenges ahead, so we need to develop new responsible mining activities, whether in France, Europe or around the world.

At present, Europe, and France in particular, are very often supplied through imports, sometimes from a very small number of countries, which raises major sovereignty issues.

Yet France, like other European countries, has significant potential mineral resources beneath its surface.

A project in line with the action plan announced by the French government in 2022

The French President announced in September 2023 that the mineral resources inventory would be updated.

This initiative follows the measures taken by the French government following the Varin report on securing supplies of mineral raw materials, which was submitted to the French government in January 2022. The report led to the creation of the Interministerial Delegation for the Procurement of Strategic Minerals and Metals (DIAMMS - Délégation Interministérielle aux Approvisionnements en Minerais et Métaux Stratégiques), responsible for coordinating the State's actions on supply issues, and the French Observatory of Mineral Resources for Industrial Sectors (OFREMI), led by BRGM.

The aim of these measures is to secure France's supply of strategic metals, thereby supporting the energy transition and re-industrialisation.

The European strategy for securing the supply of mineral raw materials

This inventory is also part of the European strategy on mineral resources, implemented to address the growing dependence of the EU's supply chains for critical metals on certain third countries.

This dependency was highlighted by the Covid crisis and then by the geopolitical consequences of the war in Ukraine, and has prompted Europe to adopt a strategy aimed at guaranteeing a sustainable and secure supply of these materials. It led to the entry into force of the Critical Raw Materials Act in May 2024.

The CRM Act sets out a series of measures aimed at:

• diversifying the European Union's sources of supply (not being more than 65% dependent on a single country by 2030),
• promoting sustainable exploration and mining in Europe (extracting at least 10% of Europe's subsurface resources by 2030),
• increasing our refining capacity (refining at least 40% of our annual consumption),
• implementing a circular economy to encourage the recycling of materials (using at least 25% of materials from recycling by 2030).

This regulation specifies that:

• each member country shall identify, qualify and quantify its strategic mineral resources,
• each member country with mineral resources in its subsurface shall adopt a national exploration programme, to be updated every 5 years,
• Europe-wide operating networks shall be established.

The aim is to reduce Europe's dependence on imports of raw and secondary materials, thereby guaranteeing security and sovereignty of supplies, while encouraging more efficient and sustainable use of mineral resources, which will help to strengthen the resilience of European economies.

BRGM's inventory of mineral resources is first and foremost a response to the need for geological knowledge of French territory and its resources. It comes before the mineral exploration process, which starts with strategic exploration. This obligation falls on the States, as they are responsible for collecting and disseminating the available geological data regarding their subsurface (on a regional scale). BRGM, as the French geological survey, carries out this task of characterising French subsurface resources on behalf of the French government.

After this strategic exploration stage, other players are likely to take over. Depending on the results of the inventory, ‘junior mining companies’ may investigate certain anomalies of interest (on a local scale), to better understand the nature of their geological potential, with a view to developing mining projects likely to interest mining companies capable of exploiting the deposits.

As shown in the following diagram, it may take up to 15 years, or even a little longer, to progress from the start of the strategic exploration phase to the eventual opening of a mine.

Déroulement et étapes clés d’un projet d'exploration minérale. L’inventaire des ressources minérales se situe en amont du processus (zone encadrée en rouge).

© BRGM

Phases d’un projet d'exploration minérale. L’inventaire des ressources minérales se situe en amont du processus (zone encadrée en rouge).

© BRGM

The energy and digital transitions are increasing demand for mineral resources. Efforts to reduce consumption, increase eco-design and recycling will not in themselves meet growing needs. Primary extraction will still be needed.

To reduce the negative external impacts, a large number of initiatives have been identified worldwide aimed at reducing and certifying these impacts, involving different types of instruments: public policy framework documents, Acts and regulations, standards and good practice guidelines, and government initiatives on value chains.

The responsible mining concept is made up of all these initiatives, which aim to:

• take greater account of the environmental, social and governance impacts associated with the extractive industries,
• ensure that this activity meets the sustainable development objectives.

These initiatives all aim to support sound mineral resource management and are based on shared principles, including stakeholder engagement, dialogue, human rights, decent working conditions, the mitigation of impacts on the climate, water, soil, air and biodiversity, reduction of chemical inputs and waste, the valuation of externalities, business integrity and transparency.

The creation of a responsible-mining standard is under debate, particularly at the instigation of Europe, and juxtaposes scientific and technical questions with political and social issues. BRGM is contributing to this through a number of studies on process efficiency and environmental monitoring, as well as by participating in more general discussions on standardisation and social and governance issues.

The concept of "responsible mining" aims to manage and limit the negative impacts of mining, both on the environment and on people.

A mining project's main concerns with stakeholders, particularly local ones, can be grouped into three main categories:

• Environmental impacts
• Socio-economic impacts
• Governance

Environmental principles: designing mines with a low environmental impact

Unlike other European countries, France largely abandoned mining on its territory between the 1990s and the mid-2000s.

Since then, mining technologies (from extraction to ore processing) have evolved. They now enable mines to be opened that are more respectful of the environment. Efforts have been made to optimise environmental performance, particularly in:

• energy savings in the initial stages and a reduction of the carbon footprint,
• optimisation of process-water circuits and better overall management of water-related issues (in terms of abstractions and discharges), including recycling the water used,
• minimising and recovering mining waste,
• minimising chemical inputs and their possible treatment,
• better integration and anticipation of post-mining phases in projects.

Social principles: respecting the rights of workers and communities

The social issues associated with mining are extremely varied and must be considered in the long term (beyond mine closures).

A responsible mining project must:

• respect workers' rights as stipulated in the Labour Code and in terms of health and safety,
• respect the rights of local populations and improve or maintain their living conditions,
• promote employment, access to education and regional development.

Governance principles: co-constructing projects with local stakeholders

A responsible mining project must ensure that local populations benefit from it economically.

This involves working on the governance and transparency of projects, and establishing constructive and ongoing dialogue with the various stakeholders, particularly those from civil society. The aim is to co-construct projects with local stakeholders.

BRGM has been working with the relevant central government departments on the projected configuration of the mineral resources inventory:

• the Inter-ministerial Delegation for the Supply of Strategic Minerals and Metals (DIAMMS),
• the Ministry responsible for Industry and Energy
• the French Ministry for Ecological Transition,
• the Secretary General for Investment (SGPI).

The IRM's technical programme was decided on the basis of multidisciplinary criteria, incorporating both scientific and public policy priorities. The resulting programme is designed to maximise the identification of areas of interest while ensuring consistency with regional policies.

The IRM is funded by the French government via the France 2030 programme. The funds are managed by the Secretary General for Investment (SGPI) via the French National Research Agency (ANR -Agence Nationale de la Recherche).

BRGM has been appointed by the French government to lead and coordinate the programme.

In this role it will draw on the services of various subcontractors, notably including a subsidiary called BRGM EXPLORE, which will be responsible for the operational implementation of the technical programme, with BRGM handling the administrative, financial and scientific sides (innovation, interpretation, dissemination).

As regards the operational implementation, the subsidiary will be able to call on specialist subcontractors, in particular for airborne-campaign flights, the collection of sediment samples and multi-element laboratory analyses.

BRGM, the French geological survey, was responsible for the previous inventory (of mainland France and French Guiana) and has all the corresponding historical data.

It has also been deploying this type of campaign and corresponding analyses for many years in various countries, particularly in Africa, to further their knowledge of their subsurface in general and its resources in particular.

Consequently, BRGM has the legitimacy and skills needed to lead and coordinate a programme on this scale. Through the inventory, it will further geological knowledge of French territory, with multiple potential applications that are not limited to the field of mineral resources.

The inventory of mineral resources is funded by the French government via the France 2030 future investments programme, at a cost of around €53 million (excluding VAT).

For updating the mineral resources inventory, five geographical areas have been targeted as priorities, because of their high potential for discovery:

• west of the Massif Central,
• the Morvan-Brévenne area,
• the Vosges,
• Occitanie-Cévennes,
• French Guiana's northern furrow.

The scope of the inventory was defined to take account of the geological characteristics of the target regions, the budgetary framework and the operational constraints of the project. However, this initial phase may be followed by further investigations in other sectors.

In mainland France, based on current knowledge, the areas that have been identified as priorities:

• have mineral resources that are known, but whose contours and extensions at depth remain unknown,
• are likely to have critical and strategic metals.

Most of the study areas include basement zones that include both magmatic crystalline massifs (e.g. the Massif Central) and sedimentary massifs (e.g. the Pyrenees), thus enabling a search for a wide range of metallic substances.

For example, magmatic terrain such as the northern Massif Central and the Vosges offer opportunities for the discovery of lithium, both in the form of hard rock and geothermal brine. The Morvan-Brévenne region is renowned for its potential in fluorite, antimony, uranium and copper-type polymetallic deposits in the Beaujolais-Monts du Lyonnais region.

In addition, sedimentary basement areas such as the Pyrénées Orientales and the Montagne Noire are known for their tungsten mineralisation, but have strong potential for germanium. Moving up towards the Morvan, the Cévennes range also offers great potential for polymetallic deposits, particularly lead-zinc, with associated antimony and tin mineralization, and even copper.

In another context, in French Guiana, the northern part of the territory is made up of geological basins containing extremely ancient rocks, bordered by major structural faults. This region is associated with various mineral deposits, including gold, copper, lead, zinc, lithium, niobium and tantalum. The geology of this area, characterised by the nature of the rocks, their age and the succession of geological events over time, offers exceptional potential for the discovery of critical metals.

Breakdown of the 5 geographical zones targeted by the mineral resources inventory.

© BRGM

The mining inventory carried out between 1970 and 1990 was limited to a small number of substances (22). One of the aims of this new inventory is to extend the analysis to include substances that were not sought 50 years ago, but which are now considered to be critical raw materials, because they contribute to the deployment of the energy transition (lithium, germanium, gallium, rare earths, etc.), the digital transition (boron, cobalt, germanium, silicon, manganese, graphite, indium, etc.), or because they are associated with strategic industrial sectors. The list now includes 55 substances of interest.

Some of these substances are known to be available in mainland France: tungsten, antimony, lithium, barium, fluorine, uranium, copper, germanium, tin, niobium, tantalum, beryllium, silver, aluminium, etc.

Matrice de criticité des substances minérales.

© BRGM

The main aim of the mineral resource inventory is to look for:

• deposits "hidden beneath the surface" (and therefore not detectable above ground) and that have never been identified in the past,
• extensions further underground of deposits that have already been identified through outcrops on the surface.

For each regional area, the work will be broken down into successive stages.

1. Preparation and documentation phase

During this bibliographic phase, the aim is to collect geological data in the broadest sense, i.e. all information that furthers our understanding of the subsurface (geophysical, geochemical, metallogenic, etc.) using data available both at BRGM and from third parties (in particular, companies that have carried out prospecting in France in the past).

This stage will highlight the nature of the geological formations, in particular by identifying the conditions favourable to the formation of deposits, such as the presence of faults conducive to the circulation of hydrothermal fluids or known signs of mineralisation.

These analyses do not require systematic geological surveys, but may nevertheless require verification and investigation in the field. They will be used to optimise the sizing of data acquisition campaigns.

2. Geophysical campaign

The second type of data will be acquired through geophysical campaigns. These can take several forms:

• Airborne geophysical surveys (using geophysical instruments carried on board an aircraft or suspended from a helicopter) to systematically cover vast areas in a short space of time. These campaigns can use different technologies:
  • magnetic/spectrometric surveys generally covering the entire area and allowing for significant depths of investigation (1000 m and more);
  • more expensive electromagnetic surveys, accurate to a depth of 500 m, which are only deployed in areas deemed to have priority in terms of potential deposits.
• Gravity surveys which, depending on the context, can be carried out on the ground or by airborne instruments, and which make it possible to identify differences in density between different geological formations.
• Depending on the context and the areas of interest, ground geophysical campaigns may also be envisaged to acquire electromagnetic and/or seismic data. These techniques can only be deployed in geographically limited areas and cannot be generalised to cover a global study zone.

3. Geochemical campaign

In addition to the geophysical campaigns, geochemical studies will be conducted. These involve sampling stream sediments, with an average density of around 1 sample every 2 km².

Sédiments de ruisseau.

© BRGM

Each sample to be characterised consists of a sufficient volume of material (around 4-5 kg), before being referenced, prepared and finally analysed in the laboratory to determine the content of various substances that can be used to detect anomalies, particularly in metals, in different areas of the region studied.

Exemple d’échantillons.

© BRGM

Taking hundreds of thousands of samples in areas that are sometimes difficult to access is the most complex, time-consuming and therefore costly part of the process. In regions where samples from the historical inventory are still available in sufficient quantity and quality, priority is given to their re-analysis, taking advantage of the new analytical techniques available, while extending the range of substances sought to include the fifty-five provided for in the new inventory.

Campagne de prélèvements pour la géochimie.

© BRGM

4. Data interpretation

The data interpretation phase is a key stage of the mineral resources inventory, which involves cross-referencing a maximum amount of data from different sources (geophysical, geological – nature of the terrain, characteristics of fault zones – and geochemical – abnormally high concentrations of certain elements) in order to identify areas that are likely to contain ore bodies of interest.

One of the challenges of this stage will be to ensure that current best practices and technologies are integrated into the data acquisition and processing steps (technologies, software, use of artificial intelligence, etc.). Particular attention will be paid to data aggregation techniques (geological, geophysical, geochemical). To achieve this, a call for innovation will be launched to mobilise companies, particularly start-ups in the field of digital innovation, capable of providing solutions to optimise data interpretation.

Technological advances, particularly in geophysical imaging and geochemical analysis, as well as advances in geological knowledge, are crucial to identifying essential metals for France and Europe.

Geophysics

BRGM has extensive experience of airborne geophysics, having conducted a number of campaigns over several decades to acquire geological knowledge for a variety of potential applications (groundwater, natural hazards, geothermal energy, etc.).

However, these techniques were not used during the previous inventory.

The geophysical approach adopted is both multi-method (using magnetism, gravimetry, electromagnetism, gamma-spectrometry) and multi-scale (using airborne and ground-based sensors). It uses innovative technologies from research and development carried out at BRGM, at its geophysical instrumentation subsidiary, IRIS Instruments, or within specialised structures. Several of these innovations have never before been deployed for strategic exploration in Europe. In particular, innovative approaches combining ground-based transmitters and airborne sensors could be tested with a view to improving the depth resolution of the inventory. Geophysical acquisitions by drone may also be tested.

It should be noted that a number of airborne geophysical campaigns carried out recently, outside the scope of the mineral resources inventory, for example in the Massif Central , the Vosges and the Monts du Lyonnais, will provide input for the results.

Geochemistry

Geochemical analyses are not in themselves new techniques, but their sensitivity has improved considerably since the last mining inventory. In addition, other innovative techniques such as hydrogeochemistry and biogeochemistry (using plants) are being considered as part of this inventory. As a large proportion of near-surface deposits have already been identified, the new geochemical exploration projects should aim to discover hidden deposits, for which conventional exploration methods are less effective.

On interpreting the data

Finally, data interpretation methods have evolved considerably since the last mining inventory was carried out between 1970 and 1990. At the time, geologists sometimes interpreted geophysical and geochemical data separately. They are now jointly interpreted, thanks in particular to the innovative predictive mapping tools developed by BRGM. An artificial intelligence algorithm combines all this information to produce maps showing the potential for discovering various mineral substances. The aim is to better define and target areas of interest based on the quality of their potential.

Airborne geophysics can cover very large areas quickly and at a low cost, including areas that are difficult to access (forests, mountains) or that have economic activity (with the exception of densely urbanised areas). It replaces long ground survey campaigns.

The three geophysical methods used provide information at various depths, from the very near surface to around the first kilometre down. The electromagnetic method will provide 3D data on the structure of the subsurface.

The data acquired will further our understanding of the subsurface and will be useful for other applications, such as groundwater, natural hazards and spatial planning.

In geochemistry, it is now possible to detect concentrations of 0.2 ppm of copper or nickel (i.e. 0.00002%), compared with 10 ppm (i.e. 0.001%) at the time of the first mining inventory. Furthermore, this technological improvement makes it possible to analyse new substances of major interest today, but also to better understand the distribution of mineral substances and to constrain the geology of the territory.

In this strategic phase of the mineral resource inventory, the methods used are non-invasive and non-destructive – in particular, no drilling or deforestation will be carried out.

Airborne geophysics provides information on the nature of the rocks found – possibly at a depth of several kilometres – without any impact on the environment.

Airborne geophysical acquisitions require low flight altitudes of between 80 and 120 metres. Permission to fly is systematically requested before any overflight. The magnetic field generated, a million times weaker than that of a mobile phone, has no impact on health.

The geochemical techniques used involve the precise, annual, manual collection of mud samples from the banks of streams, without the need for excavation. The sampling quantity will not exceed 4 to 5 kg per sampling point. Sampling plans will be drawn up in advance of the campaigns in order to carry out extremely precise work on the site, while ensuring that the methods used remain non-invasive.

Organising the inventory into geographical sectors will enable the results and deliverables to be staggered as the regional projects progress.

The final deliverables of the mineral resources inventory will show, for each site:

• the geological and structural context of the area studied and the initial knowledge available in terms of the likelihood of it having mineral resources,
• the nature of the acquisition campaigns implemented,
• the main raw data acquired.

The interpreted data will enable us to identify the most promising areas.

For each deliverable, the following will be produced:

• a summary for public distribution,
• a fuller report describing all the interpretations.

Particular attention will be paid to the referencing, quality control, archiving, processing and banking of samples and data (digital and/or physical).

The inventory will be the first stage, well before the mineral exploration process. First and foremost, therefore, we need to extend our knowledge of the French subsurface and its resources, so that we can pursue an exploration programme, if necessary, but it is also intended that it should have a variety of applications in different fields.

BRGM, as the French geological survey, is fulfilling its role of improving knowledge of the subsurface in France.

Improving geological knowledge of France for a wide range of applications

The subsurface data acquired as part of the mineral resources inventory will improve geological knowledge of our territory, particularly in terms of 3D imaging of the deep subsurface.

Modélisation 3D des objets géologiques régionaux, mis en perspectives avec les minéralisations.

© BRGM - Dubreuil et al.

The processed data will not only be used for mineral resources, but will also concern other prominent issues, particularly with a view to mitigating and adapting to climate change:

• water resources,
• deep geothermal energy,
• natural hazards and spatial planning,
• CO₂ capture and storage,
• etc.

Data dissemination initiatives will promote knowledge of the subsurface and contribute to regional development.

• All the raw airborne observations and data from the gravity surveys will be made available on BRGM's InfoTerre portal.
• They will be structured so that they can also be consulted at https://www.data.gouv.fr.
• To facilitate dissemination, the Minéralinfo portal will be regularly updated with news of data availability.

This initiative is in line with the aim of the French government and BRGM to promote the dissemination of knowledge about the subsurface to the various stakeholders concerned and to contribute to the development of skills in the region.

As regards the geochemical campaigns, the sampling plans for each sector concerned will be available for consultation at the town hall or prefecture, to make it easier to inform local residents about the field campaigns. In addition, they will also be posted on InfoTerre as the work progresses.