CHIANG RAI – An underground lead mining project backed by Chinese investors is operating near the Thai-Myanmar border under the armed protection of the United Wa State Army (UWSA). The facility is located in Mong Koe, Tachileik district, just 15 kilometers from Thailand’s Mae Sai district in Chiang Rai province.
According to a detailed field report by the Shan Human Rights Foundation (SHRF), the operation discharges hazardous chemical waste directly into the Nam Htun stream. This waterway flows directly into the Ruak River along the Thai border, which eventually empties into the Mekong River.
Key Takeaways
- Heavy Border Pollution: Runoff carrying lead and arsenic contaminates local streams that flow straight into the Ruak and Mekong rivers.
- Armed Wa Guard: The United Wa State Army provides tight security around the site following a tunnel collapse that killed 20 miners.
- Massive Thai Transit: Thousands of tons of refined ore pass through northern Thailand border crossings every month on route to global markets.
Hidden Operations Inside Border Tunnels
The mine operates right next to an older manganese site that has run since 2007. Foreign managers oversee underground tunnels that stretch 3 to 4 miles deep into the hillsides. Heavy machinery and chemical processing units sit directly above these shafts to process raw ore around the clock.
Local laborers work eight-hour shifts day and night for wages around 10,000 baht per month. Security remains tight because armed UWSA fighters restrict all access to outsiders. The militia enforced strict secrecy after a catastrophic tunnel collapse killed roughly 20 workers, keeping news of the incident quiet.
Local transport teams load extracted materials into medium trucks and head north to an area controlled by the Wa army. Once consolidated, 24-wheel heavy trucks carry the mineral loads across the second Mae Sai friendship bridge into Thailand. Thai customs data shows shipments grew fivefold recently, with minerals moving onward to China, Laos, and Cambodia.
Devastating Costs for Indigenous Villages
Indigenous Akha, Lahu, and Shan communities face severe health dangers from toxic waste runoff. Residents downstream from the processing site at Huay Sa village report sudden livestock deaths. One farmer lost 20 water buffalo within days after the animals drank from contaminated creeks.
Expectant mothers face rising rates of miscarriages and birth defects due to prolonged chemical exposure in their drinking water. Toxic sludge regularly spills over concrete retaining walls during heavy rainstorms, leaving dry toxic dust that villagers breathe daily. Local crops are failing, and skin infections have spread widely across nearby villages.
Community leaders filed formal complaints with local government representatives in early September to demand immediate safety inspections. Officials from the Shan State government and political party leaders toured the site, but authorities have not published any findings. Meanwhile, wastewater continues to flow through residential farming channels.
Toxic Runoff Reaches Thai Waterways
Regional environmental tests show this pollution is spreading across international borders into Northern Thailand. Thai water inspectors tested 22 border stations along the Sai and Ruak rivers, detecting hazardous levels of lead and arsenic at every site.
Water samples collected near the second friendship bridge revealed heavy metal concentrations far above safe national drinking standards. Downstream pumping stations serving Thai agricultural communities in Chiang Saen have also detected dangerous chemical residues.
Regional environmental groups are urging international river commissions to step in before the pollution causes permanent damage to the Mekong basin.
