Namibia’s long mining history has been shaped by open pits, underground tunnels, giant earth movers, and dredgers cutting into ancient riverbeds.
Now, the debate around Leonardville has pulled a very different method into the spotlight: in-situ recovery (ISR), a technique that mines uranium without blasting, hauling or digging.
As Parliament weighs the risks and opportunities of ISR in the Stampriet Artesian Basin, the bigger question emerges: how does ISR compare to the mining methods Namibia knows — and what does each one mean for the environment, the economy and water security?
From uranium at Husab and Rössing to gold at Navachab and B2Gold’s Otjikoto, open-pit mining has dominated Namibia’s modern economy.
It is straightforward: remove vast quantities of soil and rock to reach the ore.
The advantage is obvious. Open pits are mechanised, efficient and can move millions of tonnes of ore and waste rock with precision.
They create thousands of jobs and support entire supply chains, from blasting contractors to transport companies.
But the disadvantages are equally visible. Open pits scar landscapes permanently. Waste rock dumps and tailings dams occupy huge areas and must be monitored for generations.
Water demand is high — driven by dust suppression, processing plants and cooling systems — and in desert environments like Erongo, pits tap into aquifers already under pressure.
Acid rock drainage from waste dumps can leach heavy metals into groundwater if sulphide minerals oxidise in the open air. Unlike ISR, open pits leave behind massive voids and long-term liabilities that can outlive the mine’s revenue.
The hidden networks beneath Namibia
Operations like Otjihase, Matchless, Kombat and Tschudi have shown Namibia the intensity of underground mining: shafts, tunnels and ore passes carved deep below the earth.
Underground mining can follow narrow veins or steeply dipping ore bodies that open pits cannot reach economically.
Its advantage is a minor surface disturbance compared to open pits. The land above can sometimes be rehabilitated or returned to partial use. It also creates highly skilled, long-term jobs.
But underground mining has its own water story. Tunnels flood unless groundwater is constantly pumped out, lowering water tables over vast areas.
Mine water often contains dissolved metals, acidic drainage or sediment loads that need treatment before discharge. Subsidence can damage surface structures, and rehabilitation is complex. In contrast, ISR does not require dewatering, blasting or tunnelling — but it introduces chemical reactions into aquifers that would never otherwise encounter mining reagents.
Chemistry on the surface
Heap leaching has been used at several Namibian base-metal and gold deposits. Ore is piled onto large, lined pads and irrigated with cyanide (for gold) or sulphuric acid (for copper). Over time, valuable metals dissolve and are collected in solution.
The method’s advantage is cost efficiency. Low-grade ores that cannot justify a mill can still be processed. The footprint, though significant, is predictable and above ground.
Its weakness lies in its chemistry. If liners fail or ponds overflow during rare but severe storms, leach solutions can contaminate surrounding soils or shallow groundwater. Spills can be cleaned up, but not without cost, and liners degrade over decades. ISR, by comparison, puts the chemistry underground from the outset. If a surface heap pad leaks, the problem is visible and accessible; if an ISR wellfield leaks into a potable aquifer, the contamination is invisible and virtually impossible to recover.
Alluvial and marine diamond mining
Alluvial diamond mining — the backbone of Namdeb’s terrestrial operations — strips away layers of river and beach gravels to reveal diamond-bearing sediments. Offshore, Debmarine’s vessels vacuum the seabed to lift diamond-bearing sediments for processing at sea.
Their advantage lies in the quality and longevity of their resources. Onshore alluvial diamonds can be exceptionally high value; offshore mining extends Namibia’s diamond life for decades.
The downside is environmental reshaping. Onshore, river channels, paleosols and vegetation are removed, leaving behind large excavation areas that must be reshaped and revegetated. Offshore, seabed ecosystems are disturbed, and turbidity plumes alter habitats. Water quality for human consumption is not directly affected — a key difference between these methods and ISR.
In-situ recovery
By design, ISR differs fundamentally from all other mining methods. It does not remove rock. It does not move the earth. It does not create waste dumps, tailings or open pits.
Instead, it places wells into an aquifer, injects acid into ore-bearing sandstone, dissolves minerals in place, and pumps the solution out.
The advantage is minimal surface disturbance. No blasting, trucks or pits. No tailings to store for a thousand years. Employment needs are lower, but the surface impact is far more significant.
But the disadvantage — in Namibia’s case — is existential. ISR makes the aquifer part of the mine. Where open pits threaten landscapes, ISR threatens water bodies directly.
The risk is not dust pollution or blast vibration but chemical mobility. If leaching solutions migrate beyond the wellfield, if boreholes are poorly sealed, or if geology is poorly understood, contamination occurs in the very water source that communities drink.
ISR also demands rigorous hydrogeology. Countries that allow ISR, such as the United States and Australia, confine it to aquifers that are naturally saline, non-potable or deeply buried and geologically sealed above and below. Even then, they enforce hydraulic controls, continuously monitor wells, and require aquifer restoration or long-term attenuation monitoring after mining.
Why the difference matters for Stampriet
The Stampriet Artesian Basin is the inverse of what ISR countries consider acceptable. It is potable. It is shared across three countries. It is the only reliable water source for an entire region of livestock farmers, towns and communal lands.
Where an open pit in Erongo competes with communities for water, ISR in Stampriet would place the mine in the water. Where underground mines risk lowering water levels, ISR risks permanently altering the water’s chemistry. Where heap leach spills can be contained, ISR leaks move with groundwater, out of sight and out of reach.
A choice of methods, a choice of consequences
Namibia has built its mining economy using methods that reshape land, not aquifers. The shift to ISR represents not just a technical change but a philosophical one: moving from fighting dust to fighting water chemistry; from managing surface rehabilitation to managing underground reactions; from visible disturbances to invisible risks.
As Parliament weighs the committee’s recommendations and the communities’ fears, the comparison with traditional mining methods paints a stark choice. Namibia knows how to rehabilitate pits, reseed dunes, backfill trenches and deal with waste rock. It does not yet know — nor has any country fully mastered — how to heal a drinking aquifer once acid-leaching solutions escape into it.
The question now is not only whether ISR works elsewhere, but whether Namibia can risk applying it in a place where water is not just a resource but a lifeline.
