DRC’s Rubaya mine collapse

A landslide and mine collapse at the Rubaya columbite-tantalite (coltan) mine in the east of the Democratic Republic of Congo (DRC) killed more than 200 people at the end of January, further highlighting the precarious nature and human impact of the tantalum supply chain after years of conflict in the region.

Rubaya has long been a major source of coltan — the raw material used to produce tantalum for use in capacitors, semiconductors and super alloys — despite it coming under the control of the Rwanda-backed rebel group M23 over two years ago.

The collapse of the mine on 28 January has had an immediate impact on the tantalite supply chain, causing prices in Rwanda to spike as the flow of material from Rubaya has paused while the miners carry out funerals for those killed. Argus last assessed prices at $128-132/lb cif main airport on 5 February, up by 10pc in seven days, and prices are likely to continue their uptrend in the coming weeks.

But this is just the latest incident in a long chain of events that has put the tantalum supply chain into international focus as control of DRC’s tantalum mines has become a linchpin of M23 and its political arm Alliance Fleuve Congo’s (AFC) strategy in DRC and a headache for downstream consumers.

M23 took control of Rubaya in late April 2024 and much of the surrounding Masisi territory in North Kivu, giving it and AFC access to a wealth of tantalum concentrates (tantalite) that it has systematically smuggled to Rwanda and mixed with local supply. This material is then sold internationally, disguised as a product of Rwanda, according to a UN Group of Experts (UNGOE) report on DRC and market sources. The taxation and sale of this material could raise as much at $800,000/month to fund M23, the UNGOE has said.

After capturing Rubaya, in January 2025 M23/AFC launched a fresh offensive and seized control of the towns of Goma and Bukavu as well as large areas of territory in North and South Kivu provinces, further cementing their control over DRC’s tantalum production. M23’s control of these cities cut off many safe export routes for minerals and has enabled the group to smuggle material directly across the biggest border crossings with Rwanda.

A US-brokered peace deal between the DRC and Rwanda has so far had little impact on the conflict since its signing on 5 December in Washington. M23 were not signatories to the Washington Accords, but the deal did include provisions that both the DRC and Rwanda would stop all support for non-state armed groups. Separate peace negotiations between the DRC and M23 have continued in Qatar but have been slow moving.

In fact, fighting escalated shortly after the signing of the Washington Accords as M23 expanded south and captured the Congolese city of Uvira on the border with Burundi in mid-December. Uvira’s capture stoked fears that the group could push further south and threaten the provinces of Maniema and Tanganyika, which have so far been left out of the conflict and continue producing tantalite at monitored mine sites. The group withdrew from Uvira shortly after capturing the city, assuaging some of these fears, but the threat remains.

Can the Ta supply chain separate from central Africa?

Tantalum is one of the 3T conflict minerals along with tin and tungsten — also produced in DRC — because of a long history of these metals being used to fund conflict. As a 3T mineral, tantalum is subject to strict OECD due diligence requirements and players across the supply chain have a duty to ensure that the material they use has not funded conflict. As a result, the material produced in Rubaya and other occupied parts of DRC are not eligible for trade internationally.

But it is becoming increasingly difficult for exporters, traders, smelters and downstream players to verify the origins of the material they trade, as many companies sourcing material in Rwanda risk buying material that has been smuggled from M23-held areas.

The escalating conflict, reports of war crimes, and increased scrutiny have also brought pressure from downstream end users including major tech companies such as Apple that have urged their supply chains to avoid sourcing from central Africa.

As a result of the muddied due diligence landscape, and downstream pressure, smelters are seeking alternative supply sources in other parts of the world and disengaging from central Africa.

Trade data shows that the US’ tantalum concentrates imports from DRC and Rwanda have fallen sharply, dropping to 0t in the past two years. At the same time, China’s imports from Rwanda rose to 2,865t in 2025, up by 82pc from 1,571t in 2023, making it the largest importer of tantalite globally.

Major US smelter Global Advanced Metals has a well-established supply of tantalum concentrates from the Greenbushes and Wodgina mines in Australia, which produce tantalum concentrates as a by-product of lithium mining. Other lithium mines in Australia including Liontown Resources also produce tantalum as a by-product, with Liontown’s tantalite production rising to 591 dry metric tonnes (dmt) in the first half of its 2026 financial year, up from 246dmt in the same period of 2025.

Elsewhere, state-owned mining giant China Non-ferrous Metals Mining Group (CNMC) has secured its supply of tantalum, niobium and tin by buying a mine. CNMC bought 100pc of the shares of Mineracao Taboca in Brazil from its previous Peruvian owners Minsur SA in November 2024, giving CNMC’s subsidiary, Ningxia Orient, access to the ferro-niobium-tantalum and tin produced at the site. CNMC has since announced a $100mn investment in Taboca, aiming to double production capacity across the mine and processing plants by 2028.

Tantalum market participants have long speculated that the DRC conflict and rising prices could boost production elsewhere in the world and support the development of new conflict-free tantalite supply, but it remains to be seen if production will ever increase sufficiently to meet demand. Furthermore, disengaging from central Africa raises its own issues as the local economies of some of the most isolated and vulnerable parts of DRC are heavily reliant on income from artisanal tantalite mining.

Author name: Sian Morris, Deputy Editor, Metals, Argus Media