Berkeley Energia Reports Maiden Lithium and Rubidium Resource at Conchas Project

Maiden Resource Confirms Strategic Potential

Berkeley Energia Limited (ASX:BKY) has announced its first-ever Mineral Resource Estimate (MRE) for the Conchas Project in Spain, marking a pivotal step in its critical minerals exploration push. The inferred resource totals 11.8 million tonnes at 0.41% lithium oxide (Li2O) and 0.21% rubidium oxide (Rb2O), translating to roughly 49,000 tonnes of lithium oxide and 25,200 tonnes of rubidium oxide contained within a near-surface, muscovitic leucogranite host.

The entire resource is classified as inferred, reflecting moderate confidence and the need for further drilling and testwork to upgrade its status. Importantly, the mineralisation remains open at depth, hinting at potential resource expansion beyond the current footprint.

Geology and Deposit Characteristics

The Conchas deposit lies within the Central Iberian Zone, a prolific geological belt known for lithium mineralisation associated with highly fractionated granitic intrusions. The mineralisation is predominantly hosted in a muscovite-rich leucogranite unit, with accessory elements including tin, caesium, beryllium, niobium, and tantalum.

Drilling campaigns in 2022 and 2024 have delineated sub-horizontal mineralised layers with thicknesses ranging from 8m to 70m, supporting bulk-tonnage, open-pit mining scenarios. The deposit's location near established roads and proximity to the Portuguese border enhances its logistical appeal.

Metallurgical Testwork Validates Recoveries

Preliminary metallurgical studies conducted by SLR Consulting Ltd demonstrate very good recoveries of lithium and rubidium using flotation and magnetic separation techniques. Cleaner flotation tests at a 150µm grind delivered lithium recoveries of 77.5% at a grade of 2.23% Li2O and rubidium recoveries of 62.7% at 0.87% Rb2O. Magnetic separation further enhanced recoveries, with over 30% of lithium and 23% of rubidium reporting to magnetic concentrates.

The metallurgical results underpin the project's reasonable prospects for eventual economic extraction (RPEEE), with a conceptual breakeven net smelter return (NSR) of US$18/t. To mitigate market uncertainties, the MRE is reported at a conservative NSR cut-off of US$100/t.

Rubidium: A Rare Critical Mineral with Strategic Importance

Rubidium is increasingly recognised as a critical raw material for advanced technologies, including defence, aerospace, communications, medical imaging, and renewable energy sectors. Its applications range from night-vision equipment and fibre-optic telecommunications to atomic clocks essential for GPS and space exploration. Notably, global rubidium production is currently limited to China, raising supply chain concerns for other regions.

Berkeley highlights rubidium's strategic importance alongside lithium, which remains central to the EU’s decarbonisation and energy security ambitions due to its role in battery technology.

Next Steps and Development Plans

Berkeley plans additional infill drilling to increase resource confidence and upgrade classifications beyond inferred. A second phase of metallurgical testwork aims to optimise flotation and magnetic separation processes, potentially improving recoveries and concentrate quality.

These efforts come amid Berkeley’s ongoing arbitration claim against Spain over its Salamanca uranium project, underscoring the company’s parallel focus on critical minerals and uranium assets. The maiden MRE for Conchas thus represents a tangible milestone in diversifying Berkeley’s portfolio into high-demand critical raw materials.