By Andy Home LONDON, March 19 (Reuters) - Alphamin Resources' AFM.V decision to suspend operations at the Bisie tin mine in the Democratic Republic of Congo underscores the fragility of tin's global supply chain. Just as one of the world's largest tin mines in Myanmar shows signs of returning after a prolonged absence, another key mine closes as the M23 rebel group advances deeper into the Congo's minerals-rich Kivu provinces. Tin's supply volatility is once again generating price volatility. London Metal Exchange three-month tin CMSN3 surged 11.5% to a near three-year high of $37,100 per metric ton on the news. But the spreading conflict in Congo poses a more insidious problem for the global tin market. It's not just units that are being lost to the market, it's also transparency around the region's artisanal production. SUPPLY-CHAIN IMPACT The Bisie mine produced 17,300 tons of contained tin last year, representing around 6% of global mine supply. Alphamin Resources has been ramping up operations at what was originally an artisanal mine, targeting production of 20,000 tons this year prior to the suspension of activities. The mine has become a key supplier of raw material to China's smelters, helping compensate for the loss of supply from the Man Maw mine in Myanmar since its suspension in August 2023. The Wa State authorities controlling Man Maw have just opened the process for issuing new mining permits, flagging its pending restart. But it will take several months for operations to resume after such a long closure and the simultaneous loss of Bisie compounds China's short-term raw materials challenge. China's refined tin production has been remarkably resilient despite the loss of feed from Man Maw. National output rose by 4.6% year-on-year in 2024, according to the International Tin Association. The growth was down to unprecedented use of scrap, feeding a 14.9% year-on-year jump in secondary production, and to the drawdown of concentrates stocks, the ITA said. Inventories are much reduced, and smelters are feeling the pinch in the form of what local data provider Shanghai Metal Market describes as historically low conversion margins. The tin price reaction to the Bisie suspension suggests the market expects a knock-on impact in the world's largest producer of refined tin. LOSS OF TRANSPARENCY Alphamin's decision to evacuate all non-essential staff from the Bisie site is a sign of how far the M23 rebel group has moved beyond the captured city of Goma on the Congo's eastern border. As of March 12 the insurgents were within 125 kilometers of the mine's location in Walikale District in North Kivu. They are moving through a mineral-rich region, in which Bisie is the only official-sector tin producer. The rest of the Congo's production comes from artisanal cooperatives. Alphamin exported 27,000 tons of tin concentrate in 2024 and the unofficial sector 16,000 tons, of which 3,300 tons came from North and South Kivu, according to the Congo ministry of mines. The Kivu region has long been a testing ground for incorporating responsible artisanal production into the global supply chain not just for tin but also for tantalum, tungsten and coltan. Compliance with OECD rules on conflict minerals is led by an organisation called ITSCi, which grew out of the ITA and is now jointly backed by the Tantalum-Niobium International Study Centre. As of a February 28 update, ITSCi had suspended activities such as inspecting sites and tagging production in "some but not all areas of North and South Kivu provinces". This makes it difficult to know what is happening in the unofficial sector, assuming work is continuing at all. It also raises the possibility of tin from a widening conflict zone being illegally exported and entering the official supply chain. REPUTATIONAL RISK Such an outcome would undermine years of work in persuading end-users such as Apple Inc AAPL.O that minerals from the Congo can be responsibly produced even in the artisanal sector. The ITSCi programme is not without its critics, and is currently at the center of a lawsuit brought by the Congolese government against Apple subsidiaries in France and Belgium. But with no checks at all on how much tin is being produced in the Kivu region's unofficial sector or on where it is going, the metal of the future is in danger of regaining its problematic conflict mineral tag of the past. Evidently, the further the M23 rebels move into the Kivu region, the risks for both market and market reputation rise. The group's last-minute withdrawal from talks with the government suggests they are in no mood to stop just yet. The opinions expressed here are those of the author, a columnist for Reuters. <^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ China has turned to the Congo to help replace loss of tin supply from Myanmar https://tmsnrt.rs/41Dpo3r ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^> (Editing by Jan Harvey) ((andy.home@thomsonreuters.com, 44-207-542-4412 and on Twitter https://twitter.com/AndyHomeMetals))