A new mineral resource estimate has highlighted significant lithium and rubidium mineralisation at the Conchas project in western Salamanca province, close to the Portuguese border.

The project is being explored by Berkeley Energia, which announced its maiden Mineral Resource Estimate for Conchas on 21 July 2026. The latest company reporting confirms that exploration is continuing, with further drilling and metallurgical work planned.

11.8 Million Tonnes of Estimated Mineral Resource

The maiden Mineral Resource Estimate for Conchas totals 11.8 million tonnes at an average grade of 0.41% lithium oxide (Li₂O) and 0.21% rubidium oxide (Rb₂O).

The estimate represents approximately 49,000 tonnes of contained Li₂O and 25,200 tonnes of contained Rb₂O.

The resource also includes smaller amounts of other elements including tin, caesium, beryllium, niobium and tantalum, which occur within the mineralised rock.

The estimate was prepared by independent consultants Maja Mining Limited and reported in accordance with the JORC Code 2012.

Where Is the Conchas Project?

The Conchas Investigation Permit covers approximately 31 square kilometres in the southwest of Salamanca province.

The project lies close to the Portuguese border and is located within the municipalities of Espeja and Fuentes de Oñoro. It is approximately 21 kilometres from Ciudad Rodrigo and around 110 kilometres from Salamanca city.

The mineralisation is hosted within a muscovite-rich leucogranite associated with the eastern edge of the Guarda granitic batholith, part of the Central Iberian geological zone.

Lithium and Rubidium Mineralisation

Exploration at Conchas has been underway for several years.

According to the company's technical reporting, exploration has included soil sampling in 2021 and 2022, geological mapping in 2024, geophysical work in 2025 and drilling campaigns in 2022 and 2024.

The drilling helped establish the geological model used to estimate the current mineral resource.

The mineralised zones are relatively shallow in places, with the company reporting that mineralisation occurs from surface and remains open at depth.

This Is a Mineral Resource, Not a Mine

One of the most important points when reporting the project is its current status.

The 11.8 million tonnes is a Mineral Resource Estimate, not a proven mining reserve.

The entire estimate is classified in the Inferred category under the JORC Code. Inferred Resources have a lower level of geological confidence than Indicated or Measured Resources and require further work before they can support more detailed mine planning.

The company itself states that Mineral Resources are not Mineral Reserves and that additional technical, economic and other modifying factors would be needed before a reserve could be established.

There is therefore no basis for describing Conchas as an operating lithium or rubidium mine, or for suggesting that the reported tonnes represent material that is ready for commercial extraction.

Open-Pit Mining Has Been Considered

The current Mineral Resource Estimate has been constrained using an open-pit optimisation shell.

This indicates that the resource has been assessed using a conceptual open-pit mining scenario, incorporating estimated mining and processing costs, recoveries and potential concentrate values.

It does not mean that an open-pit mine has been approved or that construction is underway.

Further studies would be required before any future mining development could be established.

Early Processing Tests Show Recovery Potential

Preliminary metallurgical testing has also been carried out on material from the project.

The tests examined processing methods including flotation and magnetic separation and produced encouraging recovery results for lithium and rubidium in the tested material.

The company plans a second phase of metallurgical testing aimed at further optimising those processes.

Additional infill drilling is also planned as part of the company's next stage of work, with the objective of increasing the classification of the resource.

Why Lithium Matters to Europe

Lithium is particularly important to the European Union because it is classified under EU law as both a critical and strategic raw material.

The European Commission has identified lithium as important for sectors including battery production and the wider clean-energy transition.

The presence of lithium resources in Spain has therefore attracted increased attention as Europe seeks to strengthen domestic and regional supply chains for strategically important raw materials.

What About Rubidium?

Rubidium is less familiar to the general public than lithium but has a range of specialised technological and industrial applications.

Berkeley describes the rubidium resource at Conchas as globally significant and highlights potential applications in areas including advanced technology, aerospace, communications, medical uses and other specialised sectors.

However, it is important not to describe rubidium as an EU critical raw material. Rubidium is not included in the EU's current legal list of critical raw materials, although it is regarded by the company as strategically important in several markets.

Exploration Is Still Continuing

The latest company reporting makes clear that Conchas remains an exploration and resource development project.

The immediate focus is on gathering more information rather than beginning commercial extraction.

Further infill drilling is intended to improve the resource classification, while additional metallurgical testing is planned to better understand how the lithium and rubidium mineralisation could potentially be processed.

The company has also said that the mineralisation remains open at depth, leaving scope for the geological resource model to change as more exploration data becomes available.

A Developing Mineral Project in Western Spain

The Conchas project adds to Spain's growing interest in domestic supplies of minerals considered important to modern industry and the energy transition.

For now, the confirmed development is the establishment of an 11.8 million tonne Inferred Mineral Resource Estimate containing lithium and rubidium mineralisation.

What happens next will depend on further exploration, resource definition, metallurgical work and the technical, environmental, economic and regulatory assessments required before any mining project could move towards development.

For that reason, the latest announcement is best understood as a significant exploration and resource-definition milestone rather than the opening of a new mine.