Heavy rainfall caused a reservoir used by a rare earth mining company to breach in Houaphanh Province on 2 November, sending more than 1,000 cubic meters of muddy water into nearby waterways, provincial authorities said.
Officials inspected the site in Thabpheung village, Xamneua district, on 4 November to assess the damage and discuss the response.
According to the latest report by state media, the breach occurred at around 2:00 AM. Authorities said heavy rain caused soil to collapse on a steep mountainside and flow into the reservoir. The reservoir had originally been a natural stream that the company blocked with an embankment to support its mining operations.
The collapse damaged suction and water supply pipes and eroded the embankment, allowing water mixed with soil sediment to escape.
More than 1,000 cubic meters of muddy water flowed into the Duangdom stream and continued into the Nam Vaen River. The discharge made the water highly turbid and damaged rice fields belonging to two households.
A technical team took preliminary water-quality measurements at two locations. Water in the Duangdom stream, 900 meters from the site, was highly turbid, while water in the Phaboud stream, 1,500 meters away, was slightly turbid.
The inspection team said there had been no reports of dead aquatic animals and that the incident had not caused severe damage to the aquatic ecosystem.
However, final water-quality results from the National Water Quality Research Institute are still pending. Authorities said they would continue monitoring the waterways. The company has compensated the two affected households, and relevant agencies have instructed it to strengthen monitoring.
Villages Told to Stop Using River Water
Shortly after the incident, residents along the rivers have been told to stop using the water while inspections continue.
Village authorities along the Nam Vaen and Nam Xam rivers issued restrictions following reports that two rare earth ponds had burst and released chemical wastewater.
An official notice issued on 3 November ordered residents of Meuangvaen, Nakao, and Nakhoun villages to suspend all water use until inspections were completed.
The Nam Vaen joins the Nam Xam, which flows east into Vietnam, where it is known as the Chu River.
Residents of Teuam village raised similar concerns in early 2024, alleging that the Laos-China Rare Mineral Development Company North 2 Limited had discharged chemicals into a river. The then-Ministry of Energy and Mines ordered a temporary halt to mining operations while the allegations were investigated.
In April 2024, a group of villagers said a chemical leak that began on 22 February had affected 36 villages, killing fish, cattle, and buffalo.
Village authorities have not yet lifted the current water-use restrictions, and officials have not said when inspections will be completed.
