This series has spent six issues on the metals people have heard of — gold, platinum, iron, copper, cobalt, lithium. It closes on the ones almost nobody has: the heavy rare earths that make magnets work at high temperature, and the three “wiring minerals” — tin, tantalum and tungsten — that sit inside nearly every phone, laptop and jet engine on Earth. China controls the first group almost completely. A narrow geological belt running through the DRC, Rwanda, Burundi and southwest Uganda controls a meaningful share of the second. Both stories are, at bottom, the same story this whole series has told: whoever controls the exit controls the price.

01 — China’s Grip TightensSixfold Price Spikes and a Truce That Isn’t One

China controls roughly 90% of global rare earth processing and close to 99% of heavy rare earth separation — elements like dysprosium and terbium that are essential to magnets performing at high temperature, used in everything from EV motors to fighter jets. Export controls introduced in April and October 2025, targeting seven medium and heavy rare earths, triggered price spikes outside China of up to sixfold. Dysprosium oxide, priced around $200/kg inside China, has traded as high as $1,450/kg outside it; terbium oxide reached roughly $4,500/kg in some assessments, against a domestic Chinese price a fraction of that. Yttrium oxide, in single digits before the controls, hit nearly $1,100/kg by May 2026.

The second wave of controls, announced 9 October 2025, was suspended for a year until 10 November 2026 following a US-China trade truce reached at the APEC summit in Busan. The suspension has proven partial and uneven in practice: while European rare earth imports rebounded sharply after the easing, US imports never recovered to pre-restriction 2024 levels — Chinese customs data show just 17 tonnes of yttrium exported to the US in the eight months to December 2025, against 333 tonnes in the equivalent prior period. By June-July 2026, fresh controls on Japan-bound shipments and a wider set of targets signalled a return to escalation rather than resolution.

China weaponizes control, not scarcity: temporary, reversible restrictions maintain pricing power and extract strategic concessions while preventing large-scale Western alternative investment.Rare Earth Exchanges, on China’s 2026 export control strategy

02 — Rwanda’s 3T EmpireThe World’s Leading Tantalum Producer

While the rare earth story runs almost entirely through China, the 3T story — tin, tantalum, tungsten — runs substantially through Rwanda. The country has ranked among the world’s top three tantalum producers since 2008, at one point supplying 51% of global output between 2011 and 2015, and remains Africa’s largest tungsten producer and the world’s third-largest overall. Rwanda’s 3T exports grew 46.2% in 2025 alone, helping narrow the country’s trade deficit from roughly $3 billion to $2.7 billion — a shift industry participants attribute to a combination of sharply higher international prices, rising investment, and a gradual formalisation shift from purely artisanal to more mechanised mining.

Price gains have been dramatic at the producer level: one Rwandan trader described tin prices roughly doubling within a year, tantalum climbing from around $2.20 to $2.70 per unit with prospects of reaching $3, and tungsten surging to roughly $1,000 per metric tonne unit from below $350 previously — gains that have let cooperatives make advance payments, invest in better technology, and extend into underground operations that were previously constrained by oxygen limits.

03 — Uganda’s Smaller FootprintOne Mine, One Export Ban, One Closure

Uganda’s 3T sector is a fraction of Rwanda’s scale, concentrated in the southwestern Ankole region and the Karagwe-Ankolean geological system that extends the same tin-tungsten-tantalum-bearing belt across the border. The country’s most significant single asset, the Nyamuliro tungsten mine in Kabale, holds estimated reserves of 10 million tonnes of ore grading 0.5% tungsten — but has sat closed since early 2020, when owner KI3R Minerals (a subsidiary of British-backed Kerilee Investments) halted operations in direct response to President Museveni’s ban on exporting unprocessed raw minerals, leaving 2,200 daily workers without employment. The 2022 Mining and Minerals Act formalised that raw-export prohibition into law, explicitly banning export of unprocessed tin, tungsten, coltan and similar concentrates to force domestic processing — consistent with the beneficiation policy pattern this series has tracked across gold, iron ore, lithium and other minerals.

04 — Risk & GovernanceThe Coltan Question

05 — OutlookClosing the Series

• China PolicyWhether the suspended second-wave rare earth controls lapse into renewed restriction after 10 November 2026, or are extended, is the single largest swing factor for magnet-grade material prices into 2027.
• Rwanda ListingsTrinity Metals’ planned NYSE listing, if completed, would be a significant capital-markets milestone for East African mineral producers generally.
• Uganda ProcessingWhether Nyamuliro or comparable Ugandan 3T assets restart under new domestic-processing arrangements would signal the raw-export ban converting from cost to genuine value capture.
• Rwanda-DRC Peace TrackContinued implementation of the June 2025 agreement is the clearest path toward reducing cross-border sourcing risk across the entire 3T belt.