The tin market is once again bubbling on supply chain trouble, this time in Indonesia, where the government has launched a sweeping clamp-down on illegal mining.
London Metal Exchange (LME) three-month tin has jumped to over $37,500 per metric ton, the highest level since April when the supply threat was to the Bisie mine in Democratic Republic of Congo.
The latest price kicker was provided by Indonesian President Prabowo Subianto, who said the government aims to close 1,000 illegal mines in the tin-rich islands of Bangka and Belitung.
How much tin such operations produce is impossible to know, and there may be an offset if their closure leads to higher production by the country’s official sector.
But it’s another drop in tin’s cauldron of supply challenges, which is why the price is once again on the boil.
Long campaign
The Indonesian authorities have been struggling to regain control of the country’s tin production sector ever since it was de-regulated at the end of the last century.
Much of the country’s tin comes from artisanal and small-scale miners, which makes it difficult to tell who’s operating under some form of official licence and who isn’t.
Boundaries have become blurred to such an extent that PT Timah, the country’s top producer, has found itself in the dock for facilitating the black market trade.
Some of the illegal “mines” are no more than basic rafts sent out at night to dredge for tin in waters licensed to PT Timah and other official sector operators.
What’s mined is then smuggled out of the country on small boats, such as the one seized this week by the Malaysian Maritime Enforcement Agency transporting 530 gunny sacks of tin ore weighing 26.5 tons.
This latest crack of the regulatory whip actually began at the start of last month and has already resulted in multiple closures, Prabowo said.
Shadow production
How much tin comes from Indonesia’s shadow sector?
Since such material by definition eludes the country’s customs service, it exists in a statistical black hole.
Indonesia’s official export figures capture flows of refined tin, which is the only form of the metal that is supposed to be shipped overseas.
However, both Chinese and Malaysian customs departments are recording monthly imports of Indonesian “ores and concentrates”.
Chinese imports amounted to 1,192 tons in the first eight months of the year and Malaysia took in 642 tons in the first seven months, according to World Bureau of Metal Statistics data.
This may be the tip of the iceberg.
The chairman of the Indonesian Tin Exporters Association (ITEA) has told local media that up to 12,000 tons of tin are being illegally exported each year. Prabowo suggested that the shadow sector may represent around 80% of all production in the Bangka Belitung region.
While estimates inevitably differ, there is a broad consensus that the problem has become much more acute over the last year.
The illegal production boom has eaten into the official sector’s capacity. PT Timah attributed a 32% year-on-year drop in ore production in the first half of 2025 to competition with the shadow sector.
Indonesian exports of refined tin slumped to a multi-year low of 46,000 tons last year and the ITEA is expecting only a modest recovery to 53,000 tons this year.
The ongoing closure of illegal operations should in theory help the official sector lift production in compensation, although by how much and over what period is highly uncertain.
Cauldron
The tin price is in no mood to wait and find out, surging by 10% over the last week as time-spreads tighten. Just a couple of weeks ago the LME cash tin price was trading at a wide $167 discount to the three-month price. It has this week flipped to a $105 premium as shorts are forced to buy back their positions.
The price reaction to the Indonesian news says much about the fragility of the tin supply chain, which is beholden to a small number of big producers.
One of the world’s largest tin mines is still missing in action. Man Maw in the semi-autonomous Wa State in Myanmar is supposed to be reopening after a two-year absence.
However, the flow of tin raw materials over the border to China remains no more than a trickle, suggesting the mine is still far from its production rate before the authorities ordered it closed for a resource audit.
The Bisie tin mine in the Congo is back up and running after being briefly suspended in March due to the advance of the M23 rebel group.
However, the threat hasn’t gone away.
The United States is leading efforts to try and resolve the decades-old conflict in the eastern part of the Congo but no-one appears to have told the M23. One of its leaders, Kony Ng’ang’a, was in uncompromising mood in an interview last month with CNN.
Tin traders already had enough supply flash-points to worry about. They now have another one.
(The opinions expressed here are those of the author, Andy Home, a columnist for Reuters.) (Editing by Susan Fenton)
