Did the Wa State tin ban leak? Myanmar tin concentrate after the Aug-2023 Man Maw suspension

Trade-flow companion to the price wedge (R72), producer-side variant. Most cases in this corpus are consumer-side (China restricts a buyer). This one, like cobalt (DRC) and nickel (Indonesia), is producer-side: the dominant origin cut its own output, and the question flips to did the restrained tonnage leak past the cut under a neighbour's flag, or did it genuinely leave the channel? This is a DUAL-SCORE / alternative-track signal — never folded into any Tier-1 exposure score. The divergence between "the origin that stopped mining" and "who suddenly started shipping to the buyer" IS the signal. Research, not investment advice; origin-relabelling is INFERRED from statistical implausibility plus public records, never asserted as smuggling on any single shipment.

Verdict — GATE 0 (producer-side; detector-negative on laundering — the cut bit via a 12-month stockpile lag, genuine substitution, and price, not a phantom flag)

On 15 April 2023 the Wa State Central Economic Planning Commission (the administrative arm of the United Wa State Army, UWSA — a militia governing an autonomous zone inside Myanmar with no treaty standing) issued Notice Wa Jing Zi No. 2023-06, suspending all mining and processing at Man Maw, effective 1 August 2023. Man Maw alone is ~10% of global tin-concentrate supply, and Myanmar (≈70% of it from Wa State) was China's single dominant concentrate source — feedstock to the Yunnan Tin / Gejiu smelting complex (anchor action, ITA).

The buyer here — unlike cobalt's dark China reporter-wall — does publish granular import-by-origin. China's tin-concentrate imports (HS 260900) show the producer-side cut landed, but with two twists that make this a clean negative for laundering:

Source: UN Comtrade, reporter China (156), flow imports (M), annual, HS 260900 (tin ores and concentrates), pulled via the free public preview API (partner descriptions are stripped in preview and mapped here by M49 code: Myanmar 104, DR Congo 180, Australia 36, Nigeria 566, Russia 643). netWgt is gross concentrate weight (grade varies by origin), so tin-content moves are approximate; the direction and magnitude are unambiguous.

Twist 1 — the 12-month stockpile lag (the new lesson)

The ban took effect August 2023, yet Myanmar's full-year 2023 shipments to China (180,505 t) were essentially flat vs 2022 (−4%). The collapse only appeared in 2024 (−58% vs 2023). A detector that checked the flow in the immediate post-effective-date window would have concluded "the ban isn't biting" — and been wrong by a year.

The mechanism is documented: the suspension order imposed a 30% tax-in-kind on above-ground ore processed after 1 August, which accelerated liquidation rather than freezing it. Per the anchor action, July 2023 saw an export surge to clear ~1,500 t of ore stockpiled at Meng'a Port plus drawdown of an estimated ~2 million physical tonnes of raw ore / 5,000–6,000 t of concentrate potential held in Wa State. Above-ground inventory kept the pipe full through H2-2023; only once it was exhausted did 2024 register the true production halt. Lesson: for a producer-side cut on a stockpiled commodity, check the *second-year* window — the first year can be masked (or even inflated) by distress liquidation of above-ground stock.

Twist 2 — the tonnage left the channel; it did not reappear under a phantom flag

World imports fell −35% (−85,000 t). If Man Maw material were being laundered, a country with ≈0% tin-mining capacity would post a matching surge. None did. Laos, Vietnam, Thailand — the obvious land-transit candidates — stayed flat. This is structural: tin concentrate from Man Maw crosses a single land border into Yunnan; unlike antimony oxide (a processed, containerised, sea-freighted product that re-flags easily), there is no sea-transit corridor to relabel a truckload of ore. The missing tonnage was absorbed by China drawing down its own stocks, cutting smelter runs, and paying up — gross-concentrate unit value rose from ~$8,370/t (2022) to ~$10,520/t (2024, +26%) even as volume fell, and LME 3-month tin rose ~9% on the April-2023 announcement alone (anchor action).

The substitution is genuine — and, notably, non-Chinese-owned

The replacement tonnage came from real mines, not shells:

• DR Congo +44% — the surge is Alphamin's Bisie mine (one of the world's

highest-grade tin deposits, ~4% of world supply). Bisie is not Chinese-owned — majority control passed to the UAE's International Resources Holding in 2025 (filed action 2025-07-22-uae-irh-alphamin-bisie-tin-mine-drc-majority-acquisition). So China's largest single substitution reduced rather than laundered Chinese control — the inverse of the graphite/nickel mode-B pattern.

• Australia +37% (Renison) and Bolivia — genuine established producers.

Common-ownership tell: N (not traced). No namesake-shell pipe of the Youngsun→Thai-Unipet type appears. The one line that raises an eyebrow is Nigeria (+229%, 3.0→10.0 kt) — see below.

The one open flag — Nigeria

Nigeria's formal tin-mine output is small (Jos Plateau artisanal, low single-digit kt/yr), so 10,017 t of gross concentrate to China in 2024 sits at the edge of volume-implausibility. But Nigeria is a genuine historical tin producer and a documented aggregation point for West/Central-African artisanal tin, and Chinese buyers are known to be active in Nigerian artisanal metal trade. That is consistent with a mode-A aggregation/relabel corridor, but on the public data I cannot trace a named ownership pipe or prove relabelling on any shipment. It stays a labelled open question, not a laundering claim — which is exactly why this case is GATE 0 and not GATE 1.

Transmission chain & the Tier-1 blind spot

`` UWSA militia (sub-national, no treaty standing) halts Man Maw → China's smelter feedstock (Yunnan Tin/Gejiu) −58% in 2024 → masked for 12 months by 30%-tax-in-kind stockpile liquidation → filled by genuine mines (DRC/Bisie, Australia, Nigeria?) + stock draw + price → NOT by a phantom ~0%-capacity flag ``

A country-level "China tin dependence" score watches China's refined-tin exports and would miss the real chokepoint entirely: the binding node is Man Maw — a single mining district controlled by a militia — sitting upstream of the Chinese smelting complex. No country-origin exposure metric can see a sub-national actor squeeze the feedstock of the world's largest refiner. This is why the alternative track exists: the risk is a node, not a nation.

Caveats

• Inference, not proof. GATE 0. The Nigeria line is flagged, not asserted.
• Gross concentrate weight (HS 260900 netWgt) mixes grades across origins;

tin-content shares are approximate, direction is not.

• Single-shipment innocence — no individual cargo is alleged to be laundered.
• Refined-tin leg (HS 8001) not examined here — this case tests the

concentrate feedstock into China; whether reduced Chinese refined output shifted third-country refined-tin flows is an open extension.

• Data lags — 2025 recovery (Wa restart, ~1,300 t contained tin/month by

Nov–Dec 2025 per the restart action) is not yet in this annual window.

Method & sources

• Trade data: UN Comtrade, reporter China (156), imports, annual 2021–2024, HS

260900 (tin ores and concentrates), free public preview API. Partner codes mapped by UN M49.

• Control text & scale: filed action

2023-04-15-myanmar-wa-state-tin-mining-suspension (ITA documentation of Notice Wa Jing Zi No. 2023-06; Man Maw ≈10% of world concentrate; China 2022 imports of Myanmar tin-in-concentrate ~48 kt tin-content; July-2023 stockpile liquidation; 30% tax-in-kind); restart regime 2025-02-01-myanmar-wa-state-man-maw-tin-restart-licensing.

• Bisie ownership: filed action

2025-07-22-uae-irh-alphamin-bisie-tin-mine-drc-majority-acquisition.

• Production shares: USGS Mineral Commodity Summaries (tin); International Tin

Association.

This case sits between the clean-leak end of the corpus (antimony — a phantom Thailand/Mexico surge, GATE 1) and the detector-negative end (molybdenum, tellurium — a China-line collapse with genuine substitution and no leak). Tin adds a producer-side variant with a distinct signature: a real cut, masked for a year by stockpile liquidation, then absorbed by genuine mines and price — with the laundering fingerprint absent because land-border concentrate cannot re-flag.