Lotus Resources Reports Metallurgical Testwork Results for Letlhakane Project

• Metallurgical testwork supports low-acid processing flowsheet at Letlhakane, achieving approximately 70% reduction in acid consumption compared to 2015 technical study, with 6-8% reduction in uranium recovery
• New processing flowsheet removes solvent extraction stage, using ion exchange technology for uranium recovery from low-acidity pregnant leach solution
• Pre-Feasibility Study scheduled for completion in second half of 2026, with ongoing engineering work to redesign process flowsheet and update capital costs
• Resource infill drilling underway to upgrade current Mineral Resource Estimate of 142.2 million tonnes at 363 parts per million uranium oxide for 113.7 million pounds
• Letlhakane development complements Kayelekera Uranium Mine in Malawi, which commenced uranium production in August 2025

Lotus Resources Limited (ASX:LOT) is an Africa-focused uranium company with two projects in the region. The company owns 85% of the Kayelekera Uranium Mine in Malawi and 100% of the Letlhakane Uranium Project in Botswana. Kayelekera restarted production in August 2025 on time and on budget. The mine hosts current Mineral Resources of 44.8 million pounds and Ore Reserves of 23.0 million pounds uranium oxide, and produced approximately 11 million pounds of uranium between 2009 and 2014. The Letlhakane Project hosts a current Mineral Resource of 113.7 million pounds uranium oxide.

Metallurgical Testwork Results for Low-Acid Processing Flowsheet

The Australian Nuclear Science and Technology Organisation conducted metallurgical testwork at its facilities in Lucas Heights, Sydney, New South Wales. A composite sample was prepared from residuals of ore characterisation testwork completed at SGS in 2024. The average grade of the composite sample was 420 parts per million uranium (495 parts per million uranium oxide), reflecting the approach to prioritising higher-grade ore presented in the company's updated Scoping Study.

The testwork programme included benchtop work to establish negligible risk of carbon loading at intended leach acidities and bottle roll leach tests to set conditions for column leach tests. A benchmark diagnostic test estimated that high acidity conditions consistent with the previous design (100 grams per litre sulphuric acid) would result in 71% uranium extraction and 45 kilograms per tonne sulphuric acid consumption. Four column leach tests were completed under varying acid concentration conditions to evaluate a two-stage leaching process.

The low acidity application resulted in approximately 70% reduction in acid consumption compared to the 2015 A-Cap Energy flowsheet, with 6-8% reduction in uranium extraction. The resulting pregnant leach solution from the two-stage test contained less than 15 grams per litre sulphuric acid, enabling successful purification and concentration with ion exchange technology at ANSTO, which was then precipitated to make an acceptable uranium concentrate product.

Simplified Processing Approach and Removal of Solvent Extraction

The previous processing flowsheet developed by A-Cap Energy was based on high acidity leach (approximately 100 grams per litre sulphuric acid), resulting in average acid consumption of approximately 40 kilograms per tonne of ore. The company previously announced its aim to optimise the process flowsheet based on the concept that acid consumption can be reduced with minimal impact on uranium extraction by applying a two-stage leaching process where high acidity is only used in the second stage.

The two-stage leach flowsheet includes several changes compared to the original flowsheet presented in the 2015 Technical Study. The new approach reduces overall acid consumption by limiting exposure to high acidity conditions to the second leaching stage. The resultant low-acidity pregnant leach solution is suitable for recovery via direct ion exchange, removing the need for solvent extraction.

Managing Director Greg Bittar commented:

"This testwork reinforces the potential of Letlhakane to become a significant uranium operation, alongside our production at Kayelekera, as the long-term uranium price environment strengthens. The multiple column leach testwork demonstrates the ability to substantially reduce acid consumption, by up to 70%, and hence reduce operating costs as well as delivering a simplified processing flowsheet."

The column leaching approach involves two pilot columns in series, with intermediate leach solution from one column used to irrigate the first stage of a second column. Pregnant leach solution was collected from the second column for use as process liquor for ion exchange resin screening and loading/elution condition definition. The new flowsheet removes solvent extraction from the processing facility, which the company states is simpler and more aligned with traditional uranium processing flowsheets.

Pre-Feasibility Study Timeline and Resource Upgrade Drilling

The company is undertaking resource infill drilling at Letlhakane to upgrade its current Mineral Resource Estimate of 142.2 million tonnes at 363 parts per million uranium oxide for 113.7 million pounds. The Letlhakane Project hosts a Mineral Resource with 71.6 million tonnes grading 360 parts per million uranium oxide for 56.8 million pounds in the Indicated category, and 70.6 million tonnes grading 366 parts per million uranium oxide for 56.9 million pounds in the Inferred category.

The metallurgical testwork and updated Mineral Resource Estimate will support a comprehensive Pre-Feasibility Study for Letlhakane, scheduled for completion in second half of calendar year 2026. Processing and mining studies for Letlhakane are ongoing, including engineering to redesign process flowsheet and estimated capital costs, process modelling of the lab heap leach results to define new mass balance, and investigating optimal mining approach and methodology.

Bittar stated:

"The results will increase confidence in the Mineral Resource Estimate and feed into the Pre-Feasibility Study for Letlhakane, which we plan to finalise during the second half of next year."

Next Steps

Next steps to redefine the project configuration in the Pre-Feasibility Study planned for the second half of 2026 include process modelling of the lab heap leach results to define new mass balance, engineering to redesign process and update costs, and investigating optimal mining approach and methodology to minimise costs. The company continues resource infill drilling at Letlhakane whilst advancing engineering and study work for the project development.

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