DRC cobalt exports to China may have contained up to 5,000 tonnes of uranium, study finds

Cobalt hydroxide exported from the Democratic Republic of the Congo to China between 2000 and 2024 may have contained an estimated 2,000–5,000 tonnes of uranium, according to a peer-reviewed study developed alongside an investigation by Lighthouse Reports and the Financial Times.

The quantitative estimate came from scientific modelling, while the investigation supplied trade data, leaked documents, regulatory records and source reporting used to test and refine the findings.

The researchers said the uranium contained at the lower end of the estimate would, after recovery and processing, be sufficient in energy terms to fuel a one-gigawatt nuclear reactor for at least a decade.

The investigation found no evidence establishing whether uranium was recovered from the Congolese material after it reached China or how any recovered material might have been used.

Researchers combined geological records, mine-output figures, trade data and models of uranium concentrations in cobalt deposits across the DRC’s southeastern Katanga region.

Ryan Manzuk, a geologist and postdoctoral researcher at Princeton University, and Sébastien Philippe, a nuclear-engineering researcher who later joined the University of Wisconsin-Madison, developed upper and lower estimates for uranium contained in exports from individual mines.

They examined previous analyses of uranium concentrations at Katanga deposits and extrapolated the findings across operating mines using geochemical models. They also consulted geological samples held by Belgium’s AfricaMuseum.

Imports of phosphoric acid, one chemical used to separate uranium from cobalt material, appeared insufficient to support removal at the scale assumed in the model, according to the investigators.

Lighthouse Reports and the Financial Times said their analysis indicated that large imports of the chemical often followed incidents in which contaminated shipments had been flagged.

Researchers also tested whether hyperspectral satellite imagery could identify uranium-rich minerals in mine waste, but atmospheric interference and insufficient reference spectra prevented reliable results.

The investigation began after Lighthouse Reports obtained a previously unpublished International Atomic Energy Agency (IAEA) memorandum dated 2009.

The memo cited information indicating that significant quantities of uranium were present in much of Katanga’s cobalt ore and were being exported as an undeclared by-product of cobalt production.

Since the memorandum was written, the DRC’s cobalt industry has expanded rapidly. China refined about 80% of the world’s cobalt supply by 2023, while an estimated 95% of Congolese cobalt was sent to China, according to figures cited by the investigators.

Katanga’s deposits naturally contain copper, cobalt and uranium. The region’s Shinkolobwe mine was historically one of the world’s richest uranium sources and supplied much of the material used by the United States’ Manhattan Project during the Second World War.

The investigation said Congolese rules prohibit uranium exports and impose limits on radioactive contamination in cobalt products.

Interviews with mining executives, traders and metallurgists indicated that testing across the supply chain was inconsistent, Lighthouse Reports said.

Some industry specialists described separate supply chains for higher-grade material subjected to additional treatment and lower-quality cobalt products containing more impurities, including uranium, destined mainly for China.

Leaked internal records from Tenke Fungurume Mining, one of the DRC’s largest copper and cobalt operations, showed uranium concentrations reaching 1,100 parts per million in December 2016, about 15 times the export limit cited by the investigators.

The investigators said leaked testing records showed concentrations above that threshold on more than 70% of recorded days between June 2016 and December 2020.

The records concerned material tested at the operation and did not establish that each batch was exported or that its uranium concentration was unchanged when it left the site.

Internal memoranda also described experiments intended to remove uranium from cobalt hydroxide during the period covered by the records.

Three sources familiar with the operation told the investigators that a comprehensive removal system was not implemented. A second group of leaked records indicated that significant uranium concentrations remained in some Tenke cobalt batches as late as June 2021.

Freeport-McMoRan (NYSE:FCX) agreed to sell its controlling interest in Tenke Fungurume to China Molybdenum, now known as CMOC Group (SSE:603993; HKEX:3993), in 2016, during the period covered by the leaked records.

CMOC rejected the investigation’s findings, saying there were no cases in which uranium exceeded applicable limits and that Tenke’s cobalt hydroxide complied with Congolese rules and customers’ procurement requirements.

The company also said it did not recognise the source of the historical records cited by the investigators. Freeport-McMoRan declined to comment.

The investigation separately examined the handling of uranium at Freeport-McMoRan’s former cobalt refinery in Kokkola, Finland.

Documents from Finland’s Radiation and Nuclear Safety Authority showed that a 2014 permit authorised the refinery to separate and store uranium recovered from cobalt material for 10 years, provided the quantity remained below 10,000 kilograms in any calendar year.

Lighthouse Reports said the threshold marked the point at which additional IAEA nuclear-material safeguards requirements would apply.

Belgian metals group Umicore, the current owner of the Kokkola refinery, said uranium was treated as an incidental impurity rather than as a commercial co-product. It said the facility operated under regulatory and contractual acceptance standards.

The DRC has a comprehensive IAEA safeguards agreement and an additional protocol, but those arrangements are designed to verify declared nuclear activities and materials rather than replace radiation screening at mines and border crossings.

An IAEA expert told the investigators that the agency believed the DRC was meeting its safeguards obligations and that uranium contained in cobalt material generally remained in mining tailings.

Those comments did not resolve the study’s separate claim that uranium-bearing cobalt material may have crossed the border without systematic detection.

Steve Muanza, head of the DRC’s nuclear energy agency, told the investigators that post-export extraction was technically possible and, in his view, likely.

His agency has requested funding to install radiation-monitoring equipment along National Highway One, which is used by mineral trucks travelling from southeastern mining areas towards the Zambian border.

Weak monitoring capacity, limited equipment and the DRC’s long and porous borders make it difficult to determine how much radioactive material leaves the country, according to the investigation.

The findings raise questions about possible occupational exposure and contamination around mining waste, although the investigation did not quantify health effects or establish causation in specific communities.

The investigation also did not establish that any uranium was recovered, entered China’s nuclear sector or contributed to weapons production.

The study nevertheless raises the possibility that significant quantities of uranium travelled within a cobalt supply chain without being separately declared or consistently monitored.