More testing for Uranium One
The International Atomic Energy Agency (IAEA) has called for additional groundwater investigations at Uranium One’s proposed Wings uranium project near Leonardville to establish whether chemical solutions used in mining can be prevented from spreading into neighbouring groundwater sources.
The agency found that Headspring Investments, the company developing the project, has not provided sufficient field evidence to demonstrate that the uranium-bearing Auob aquifer is adequately isolated from the overlying Kalahari aquifer, which contains potable groundwater.
The finding is among the most significant concerns raised in an independent technical review commissioned by the Namibian government to assess the environmental impact assessment and management plans for the proposed pilot uranium recovery operation in the Omaheke Region.
The IAEA identified 27 areas requiring improvement, but placed particular emphasis on demonstrating that mining solutions can be contained within the intended uranium-bearing formation before the company proceeds with chemical leaching.
The proposed operation would use in-situ leaching, a process in which chemical solutions are introduced into underground uranium-bearing formations to dissolve uranium before the resulting liquid is pumped to the surface for processing.
The method requires careful control of underground fluid movement to prevent the mining solution from migrating beyond the intended operating area.
“Demonstration of aquifer confinement and the ability to maintain hydraulic control are fundamental prerequisites for ISL operations. The Proponent’s current documentation asserts confinement but does not provide comprehensive empirical evidence to support this conclusion,” the IAEA states.
Separation between aquifers not demonstrated
The review found that Headspring’s environmental documentation relies partly on regional geological information and conceptual assumptions rather than sufficient measurements from the proposed mining site.
Of particular concern is the separation between the Auob aquifer, where uranium recovery is proposed, and the Kalahari aquifer above it.
The IAEA said the company must demonstrate that the geological formations separating these groundwater systems can prevent the movement of mining solutions between them.
The experts recommended installing additional monitoring wells in the overlying and underlying formations to measure groundwater pressure and identify possible hydraulic connections.
They also called for further investigations into geological faults and fractures that could provide pathways for underground fluids to move outside the intended mining area.
Existing and abandoned boreholes require closer examination because poorly sealed wells could also create connections between otherwise separated geological formations.
The review found that although the company’s documentation recognises the need for proper well construction and sealing, it does not provide sufficient technical detail on how well integrity would be verified under operating conditions.
Mining solutions must remain contained
Beyond demonstrating geological separation, the IAEA wants Headspring to provide stronger evidence that it can maintain hydraulic control throughout the pilot operation.
This involves managing underground pressure so that mining solutions remain within the designated uranium-bearing formation and can be recovered through pumping wells.
The experts found that the company’s modelling does not adequately account for all conditions that could influence underground fluid movement, including regional groundwater gradients, pressure changes and pumping activities outside the project area.
They recommended more detailed modelling and testing to establish how the system would respond under different operating conditions.
The IAEA also wants the company to demonstrate how it would detect and respond to any movement of mining solutions beyond the intended operating zone.
This would require clearly defined monitoring arrangements, warning thresholds and contingency procedures capable of identifying potential leakage before it affects surrounding groundwater.
The agency found that the proposed monitoring arrangements need stronger integration with the project’s operational controls and environmental management plans.
