The International Atomic Energy Agency (IAEA) says in-situ recovery (ISR), also known as in-situ leaching, is an accepted uranium mining method only when strict geological, hydrogeological and regulatory conditions are met, including complete protection of groundwater systems.
In its publication In Situ Leach Uranium Mining: An Overview of Operations, the IAEA defines ISR as a process in which ore remains underground while a leaching solution is injected to dissolve uranium, which is then pumped to the surface for processing.
The agency notes that ISR has become a significant source of global uranium production, particularly in Kazakhstan, the United States, China and Uzbekistan.
However, across its technical reports, safety guides and environmental manuals, the IAEA stresses that ISR is suitable only for particular types of deposits.
According to IAEA guidance, uranium orebodies must lie in permeable sand or sandstone formations, and these must be confined above and below by low-permeability or impermeable layers to keep leaching fluids contained. The target aquifer must also be fully saturated and exhibit predictable groundwater flow.
The agency outlines similar conditions in its environmental assessment manual, Environmental Impact Assessment for In Situ Leach Mining Projects (TECDOC-1428).
The IAEA requires ISR EIAs to include a detailed description of the baseline hydrogeology, a groundwater-flow model, a complete monitoring-well network, the chemical composition of leachate, and a restoration and closure plan demonstrating how groundwater will be returned to agreed standards after mining.
The IAEA warns that groundwater protection must be central to the regulation of ISR. In its safety guide on managing residues containing naturally occurring radioactive material, the agency lists groundwater quality standards, baseline monitoring, operational monitoring and post-closure monitoring as mandatory regulatory elements.
Earlier manuals on acid ISR stress that well casings, cementing and sealing must be robust enough to prevent leakage between aquifers, and that injection pressures must be controlled to avoid migration of leaching solutions.
The agency also distinguishes ISR projects that require extensive groundwater restoration and those that do not. A technical summary associated with IAEA guidance states that remediation is more likely to be needed where others use the aquifer, where it is hydraulically connected to surrounding aquifers, or where the groundwater meets drinking-water or agricultural standards.
It is less likely to be required where aquifers are poorly connected and the groundwater is of inherently low quality.
In its broader assessment of ISR worldwide, published in the SADC-GMI groundwater conference proceedings, the IAEA underscores that leakage to other aquifers must be prevented, a requirement highlighted repeatedly in safety literature.
The agency does not comment on national projects, but its technical publications make clear that ISR is typically applied in non-potable, mineralised or saline aquifers. According to the IAEA and the World Nuclear Association, ISR production in countries such as Kazakhstan, Uzbekistan, China and the United States generally occurs in groundwater that is not used for drinking, is often too saline for human or livestock use, sometimes contains naturally elevated levels of uranium, arsenic and dissolved solids, and is in aquifers that the US EPA or local regulators have formally exempted from drinking-water protection standards.
The World Nuclear Association notes that the majority of ISR operations worldwide are conducted in brackish or low-quality aquifers, which allows regulators to focus on containment without simultaneously protecting active water-supply zones.
Many of these aquifers are hydraulically confined, meaning impermeable rock layers isolate the mining zone, a key condition repeatedly emphasised in IAEA guidance.
In contrast, studies of the Stampriet Artesian Basin describe it as a freshwater drinking aquifer supplying communities, livestock and irrigation in a semi-arid region where no alternative perennial water source exists.
Hydrogeological research shows the Stampriet system is hydraulically connected, with sandstone layers, fractures and artesian pressure that allow groundwater and any dissolved contaminants to migrate across formations.
These differences are central to IAEA assessments. The agency’s publications indicate that ISR is generally appropriate only when mining occurs in non-potable, isolated aquifers.
In contrast, caution is required when others use the aquifers, when they are hydraulically connected, or when they are of high quality.
The agency’s guidance makes clear that ISR is acceptable only when leaching fluids can be fully contained within the ore zone, regulators can verify containment and monitoring, and there is a credible plan to restore groundwater to safe levels after mining ends.
For any consideration of ISR in the Stampriet basin, Namibia would have to meet a far higher threshold than countries where ISR is already practised.
The Water Resources Management Act has declared the area a Water Protection Zone, and any decision to allow ISR would have to be reconciled with that legal status. The government would need a detailed, peer-reviewed hydrogeological model showing that the ore zone can be hydraulically isolated in practice, despite existing evidence of connectivity between aquifers.
Any new environmental assessment would have to meet full IAEA standards, including baseline water-quality datasets, calibrated groundwater-flow models, detailed wellfield designs, and long-term restoration plans that demonstrate how potable-water conditions would be maintained or restored.
The transboundary nature of the Stampriet system means Namibia would also have to formally consult Botswana and South Africa, because any contamination plume or perceived risk could cross borders.
Operational safeguards would have to include extensive monitoring of well networks, strict control of injection pressures, robust casing and cementing, and enforceable emergency protocols with real-time monitoring capacity.
The country would also need strong enforcement mechanisms, financial guarantees for long-term water restoration and monitoring, accredited independent laboratories, and clear regulatory thresholds that would trigger the suspension of operations.
Because the Stampriet basin is the only perennial water source for thousands of residents, livestock, and irrigation farms, Namibia would also have to demonstrate regulatory oversight comparable to that of jurisdictions with decades of experience with ISR.
In practical terms, this means stronger inspection teams, transparent public reporting, independent expert panels and a credible mechanism for communities to raise objections based on scientific monitoring.
Taken together, the IAEA’s global conditions and Namibia’s local realities mean the threshold for permitting ISR in the Stampriet would be significantly higher than in countries where ISR is already established.
The combination of potable water, transboundary obligations and a legally protected aquifer places Namibia in a category where the IAEA’s most cautious guidance applies, and where any approval would require exceptional scientific evidence, regulatory capacity and long-term safeguards.
