- Satellite data reveal 513 rare earth mining sites across rivers feeding into the Mekong, Salween and Irrawaddy in Myanmar, including 40 new ones in 2025 — far more than previously estimated.
- Toxic runoff from unregulated mines in Shan and Kachin states has polluted rivers flowing into northern Thailand, causing some $40 million in losses to farming, fishing and tourism.
- Communities in the Thai provinces of Chiang Mai and Chiang Rai are struggling with contaminated water and weak government response, prompting grassroots groups to demand testing, clean water sources, and a halt to imports from Myanmar.
- China’s tightening controls and rising demand for rare earths have fueled Myanmar’s mining boom, with conflict and lax oversight allowing environmental destruction and cross-border pollution to spread downstream through Southeast Asia.
BANGKOK — New satellite data identified 513 sites of rare-earth mining that have cropped up across at least six key tributaries of the Mekong, Salween and Irrawaddy rivers in Myanmar over the past 10 years. These include 40 believed to have opened this year alone, with the total marking a dramatic increase from previous estimates and suggesting the risk of transboundary river pollution is significantly higher than once thought.
The new data and analysis from nonprofit think tank the Stimson Center, published Sept. 22, warns that the proliferation of unregulated mining operations in Myanmar, which are already having dire outcomes in northern Thailand’s Chiang Mai and Chiang Rai provinces, could be worse for the region’s rivers than expected.
Brian Eyler, director of the Stimson Center’s Southeast Asia program, who conducted research on the river contamination in northern Thailand, said further testing is urgently needed.
He urged other countries to begin testing their waterways potentially as far afield as Cambodia and Vietnam, because the potential for acids, heavy metals, arsenic and other toxins linked to mining flowing downstream is now significantly higher than previously reported.
This testing, he added, needs to include the water, sediment and surrounding soil from rivers. It was the “sticky mud” that inundated parts of northern Thailand following heavy rainfall that first alerted his team to contamination on the Kok River, which flows into Chiang Mai’s Mae Ai district from Myanmar, before going on to feed into the Mekong River in Chiang Saen district, Chiang Rai.
“That’s what’s sticky about [the mud] – it’s composed of all these heavy metals and chemicals,” Eyler said. “The Sai River actually has the worst levels of pollution of the rivers tested by Chiang Mai University, much worse than the Kok River, although the Kok River is still bad.”
The Sai River crosses from Tachileik in Myanmar to Thailand’s northernmost point — Mae Sai in Chiang Rai province — before flowing into the Ruak River, which in turn empties into the Mekong River before this major river system flows onward through Laos, Cambodia and Vietnam.
Both the Sai and Kok rivers have carried toxic chemicals from mines in Shan state, Myanmar. (Both rivers trace their origins to the state’s Daen Lao mountains.) From Shan, they flow to communities in northern Thailand that are heavily dependent on rivers for survival, causing an estimated 1.3 billion baht ($40 million) in losses across the farming, fishing and tourism industries.
In Tha Ton subdistrict of Chiang Mai and Mae Sai district of Chiang Rai, the Kok and Sai rivers respectively provide communities with water for drinking and for household and agricultural use. But this has all been heavily contaminated, largely with chemicals associated with rare earth mining activity.
“We went to Tha Ton and they’re so desperate there,” Eyler said. “They told us they’ve lost their economy, they don’t know whether the water is safe, they worry they’ll get sick and there’s not a lot of understanding or communication about the health implications of being in proximity to these chemicals — it’s tearing their communities apart.”
The Network for the Protection of Kok, Sai, Ruak, and Mekong Rivers, a community-led grassroots organization, has sprung up to fill the gap left by the largely absent Thai government’s response to this unfolding crisis, communicating scientific research to affected communities and calling on the government to do more.
In early October, the network filed a 10-point petition to the new Thai government, demanding soil monitoring across roughly 16,000 hectares (39,500 acres) of potentially contaminated farmland, the development of alternative water sources, and the establishment of provincial heavy metal testing facilities.
The petition also called for a halt to all mineral imports from Myanmar until said commodities could be proven pollution-free, while also calling for regional negotiations between China, Myanmar and Thailand to address the mining crisis.
Myanmar mined for the modern economy
Rare earth minerals are predominantly found under mountains or hills, making Myanmar’s states of Kachin and Shan lucrative deposits. In Myanmar, rare earth minerals are commonly mined using a technique similar to fracking, in which water is mixed with a variety of chemicals and injected into the ground via leaching ponds, pushing a liquified mix of minerals and mud into collection pools below.
Once the mountain has been drained of the mineral-rich solutions, these pools of chemicals are simply abandoned as miners move onto the next mountain.
“The rare earth mineral mines proliferate rapidly because they occur in proximity of one another, it’s in the soil all around these rivers, so once one mining site is used up, the miners will just move to the next hill,” Eyler told Mongabay in a phone interview. “Each site only lasts about three years, but wastewater pools just stay there, many filled with contaminated substances so that when you get heavy rain, that pushes it out of the pools and into local streams below.”
As the monsoon season peaks across Southeast Asia, Eyler said the extra rain will serve to both dilute the existing pollution in rivers and to exacerbate the risk of yet more wastewater overflowing from mining operations into rivers.
Rare earth minerals consist of 17 metallic elements and are, despite what the name suggests, considered abundant. But they’re rarely found in large concentrations and are often mixed in with other ores, minerals and metals. Rare earth minerals are used in a wide range of products, including magnets, smartphones, batteries, wind turbines and solar panels, and are crucial to the energy, aerospace and health care sectors. Many of the products manufactured from these minerals require large quantities: electric cars need six times as many minerals as internal combustion engine cars, while wind farms require nine times as many as a natural gas plant. Other products containing rare earths, like the semiconductors fueling artificial intelligence data centers, create their own set of environmental problems.
China holds the world’s largest supply of rare earth minerals and also dominates the global processing capacity. As of 2024, there were an estimated 44 million metric tons of rare earth reserves across the country. But the widespread environmental damage that’s resulted from extracting this supply has led to the Chinese government to imposing quotas on domestic rare earth mineral mines, closing mines that aren’t environmentally compliant, and imposing stricter controls on how these mines operate.
In October 2025, China tightened restrictions on the export of rare earth minerals, requiring exporters to be granted permission from the government to sell the minerals abroad. This prompted stockpiling of key rare earth minerals by the U.S. government, particularly those needed for the defense and aerospace sectors.
China sits upstream of the myriad environmental woes its overseas sourcing of rare earth minerals creates, leaving its southern neighbors with the task of cleaning up.
Since December 2023, China has banned the export of technology used to process these minerals, cementing its control of the market and expanding its reliance on rare earth mineral imports.
Myanmar has become a key player in filling China’s supply chain gap following the 2021 coup carried out by the Myanmar military. While the previous civilian government banned rare earth mineral exports in 2018, this ban was ignored at the time by various ethnic armed groups that have long controlled territory outside the central government’s control. Since the coup, some of these ethnic armed groups have aligned with people’s defense forces that oppose the junta, providing training and weapons to those seeking to resist the junta.
Other ethnic armed groups have sought to autonomously expand their territories in pursuit of precious resources, leaving a trail of environmental problems and rights abuses in their wake. It’s here where Chinese demand has seen a spike in rare earth mineral mining operations from 2022 onward.
Locally, in Kachin and Shan states, where rare earth mining is at its most prolific in Myanmar, the forests are paying the price, with tens of thousands of hectares of tree cover vanishing as mining operations expand from hilltop to hilltop.
One regularly touted estimate suggests that for every ton of rare earth extracted, 2,000 tons of toxic waste is produced, including 75 cubic meters (nearly 20,000 gallons) of wastewater.
From the Irrawaddy to the Mekong and beyond
Kachin state, where 451 rare earth mines opened in the Irrawaddy River Basin over the last decade, emerged as a hotspot for rare earth mining since 2018. Mining expanded rapidly after the 2021 coup, with 260 of the 451 identified mines opening since then.
However, the number of new mines there declined significantly between 2024 and 2025 as production shifted with the fluidity of the ongoing conflict.
According to Jason Tower, a researcher working with the Global Initiative Against Transnational Organized Crime, mining shifted from Kachin state to Shan state in December 2024 after the Kachin Independence Army (KIA) defeated the forces of the New Democratic Army–Kachin (NDA-K). The latter is led by Zahkung Ting Ying, a key partner of Chinese mining companies, who has since fled to China and is trying to rebuild his mining empire.
The KIA then sought to impose heavier taxes and stricter environmental regulations on Chinese-run rare earth mines, prompting Chinese mining companies to seek out new hubs of production with fewer restrictions, Tower added.
In Shan state, the Stimson Center’s data show a trend of the Mekong River Basin becoming increasingly important for rare earth miners. Of the 58 mines seen along the Ruak, Lwe and Kok rivers — key Mekong tributaries — 44 were opened between 2022 and 2025.
None of this offers much in the way of hope for communities in Myanmar or Thailand ravaged by toxic runoff from these rare earth mines. Assessing the impact on communities in Myanmar remains difficult due to the restricted access to areas controlled by the ethnic armed groups.
Tower warned that, as the situation in Shan state and along the Thai border continues to deteriorate due to water pollution, it remains unlikely that either the Myanmar junta or the United Wa State Army will address this issue.
“The Myanmar military itself has no capacity or interest in engaging in any form of environmental protection, and instead is presently attempting to use airstrikes and military campaigns to retake control of the mines,” Tower said. “For its part, the [United Wa State Army] has previously indicated some concerns about environmental impacts of mining, but has done little in practice when it comes to regulation. It is further unlikely that China would put in place measures to influence how mining of [rare earths] is conducted in Myanmar given that any move to do so would function to undermine its price advantage.”
Banner image: The Kok River, flowing from Myanmar’s Shan state into Thailand’s Chiang Mai province, has become contaminated with toxic chemicals associated with rare earth mineral mining. Image supplied by Brian Eyler.
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