The southern Democratic Republic of Congo is best known today as the world's most important source of cobalt, the metal at the centre of the lithium-ion battery supply chain. The same rocks that make the region indispensable to the energy transition also made it the birthplace of the nuclear age — and new peer-reviewed research argues those two stories are now colliding, with substantial quantities of uranium likely leaving the country inside cargo the world records only as cobalt.
The findings, published in Nature Communications and described for The Conversation by geologist Ryan A. Manzuk, represent the first systematic attempt to connect cobalt production in the Congolese Copperbelt to the uranium that travels alongside it. The central claim is blunt: the Democratic Republic of Congo has not officially reported any uranium exports for decades, yet the region's geology and its industrial chemistry both point to a very different reality.
From the Manhattan Project to the battery boom
The Copperbelt in southern DRC earned its name from the rich deposits of copper and other minerals packed into the ground there. Its place in history, however, was secured by something else entirely. Ore from the Shinkolobwe mine in the country's southeast became the primary source of uranium for the first nuclear weapons built by the United States' Manhattan Project, which ran from 1942 to 1947. Two atomic bombs were subsequently dropped on the Japanese cities of Hiroshima and Nagasaki in 1945.
Shinkolobwe has been officially closed to excavation since 2004, and in the years since, the DRC has declared no uranium exports at all. That official silence is precisely what makes the new work notable. The research suggests that uranium has not stopped leaving the Copperbelt; it has simply stopped being counted as uranium.
Why cobalt and uranium are so hard to prise apart
The study's core insight rests on two facts that earlier analyses had not treated as a matched pair.
- They occur together naturally. Uranium and cobalt are found in the same rock formations across the Copperbelt, a geologic co-occurrence that is a feature of the deposit type rather than an accident of sampling.
- They behave alike in processing. When ore is put through chemical treatment, the two elements respond in broadly the same way, which makes clean separation difficult and expensive.
Because uranium and cobalt follow similar chemical pathways, material that enters the supply chain as cobalt ore can carry uranium with it through the steps used to prepare a saleable concentrate. Manzuk, a geologist who specialises in analysing the chemical and mineral composition of rocks, works largely from a map-based perspective, drawing conclusions from spatial data such as regional cobalt statistics. By treating the geology and the processing chemistry as a single system, he and his colleagues were able to produce one combined estimate of how much uranium is implicated whenever Copperbelt cobalt is mined and exported.
Building an estimate from thin public data
The obvious obstacle is transparency. Very few data points are publicly available describing uranium concentrations in the ores being mined, or the specific chemical steps used to prepare cobalt for shipment. Any estimate therefore has to be assembled rather than simply read off a ledger.
The researchers' approach was to model each link in the chain. They used geologic maps to infer the likely uranium grades present in cobalt ores. Those grades were then combined with the volumes of ore being processed at individual facilities across the Copperbelt. Finally, they layered on a model of how uranium behaves during the processing chemistry that occurs before material is shipped. The output of that chain is a direct link between cobalt production figures and probable uranium export.
What the numbers suggest
Under the most likely scenarios, the calculations point to 2,000–5,000 tonnes of natural uranium being tied to that cobalt trade. The range reflects the uncertainty baked into the modelling rather than a firm measurement, but its scale is the reason the paper has attracted attention: it describes a material flow that is large enough to matter globally, yet invisible in official trade reporting.
It is worth being precise about what is and is not being claimed. The study does not allege smuggling, deliberate concealment or any particular intent. It argues that the physical realities of the Copperbelt — co-occurring elements and closely related processing behaviour — make uranium a routine, largely unremarked component of a cobalt industry that has expanded enormously to meet battery demand.
Why unreported uranium matters for nuclear risk
Natural uranium is not a weapons-ready material on its own, and nothing in the research suggests that what is leaving the Copperbelt is destined for a weapons programme. The concern is more structural. International efforts to track nuclear material depend on declarations: a country reports what it produces and exports, and those figures feed into the accounting that allows others to verify that nothing is missing.
When a stream of uranium moves without being declared, it sits outside that accounting entirely. It cannot be tracked, verified, or reconciled against production records because, on paper, it does not exist. The result is a blind spot that grows quietly with every shipment — and one that becomes harder to close the longer it persists. In that sense, the risk the researchers describe is less about any single consignment than about the integrity of the global picture of where nuclear materials are and who holds them.
The limits of a modelled result
The authors are explicit that their conclusion is an estimate derived from incomplete inputs. Several caveats follow from that.
- Uranium grades in Copperbelt ores are inferred from geologic mapping rather than measured at every site.
- Processing details at individual facilities are not fully public, so the chemistry is represented by a model.
- The 2,000–5,000 tonne range captures the spread between more and less likely scenarios, not a statistical confidence interval.
- Official DRC export data cannot confirm or contradict the estimate, since no uranium exports are reported at all.
Even with those qualifications, the study's contribution is methodological as much as numerical. It shows that co-occurrence and processing behaviour can be combined into a workable framework for estimating a material flow that nobody is currently measuring directly — and it invites others to test the result against independent data.
What happens next
The practical implications unfold on two tracks. On one, better disclosure from mining and processing operations — ore grades, chemical flows, concentrate composition — would allow the estimate to be replaced by measurement. On the other, the countries and institutions that consume Congolese cobalt and the agencies that watch nuclear materials have a shared interest in knowing whether the modelled flow is real.
For now, the Copperbelt remains what it has always been: a place where the energy transition and the nuclear age are dug from the same ground. The question the new research raises is whether the world's accounting has kept up with that fact.
This article is based on reporting by Phys.org. Read the original article.
Originally published on phys.org
