PHNOM PENH — A government investigation has found that Indian-owned Mesco Gold (Cambodia) Ltd discharged liquid waste into a natural stream in Ratanakiri province, contaminating the water and depleting oxygen levels, which led to widespread fish deaths.
Inspectors from the Ministry of Environment visited the company’s site in Yatung commune, O’Yadav district, on October 4 to examine the source of the contamination. They collected liquid waste and stream water samples from five separate locations for laboratory testing at the ministry’s central facility.
In 2016, the Ministry of Mines and Energy granted Mesco Gold (Cambodia) Ltd the country’s first-ever industrial mining license, authorizing the company to operate a 12-square-kilometer underground gold mine in Phum Syarung, O’Yadav district, under a 30-year concession.
At the time, JK Singh, chairman of Mesco Gold’s parent company, the Mesco Group, described the approval as a milestone for Cambodia’s mining sector. “The issuance of this license marks the beginning of a new era for the country’s mining industry, which until now had been limited to exploration,” he said in a statement.
Mesco Gold (Cambodia), a subsidiary of the Indian steel manufacturer Mesco, acquired the rights to develop and operate the Phum Syarung deposit from Canada’s Angkor Gold Corp in 2013.
Angkor Gold, which holds six exploration licenses across northwestern Cambodia, sold its O’Yadav concession to Mesco Gold for $1.9 million. As part of the deal, the Canadian firm retained a net smelter royalty agreement of between two and 7.5 percent, entitling it to a share of revenue from any gold produced at the site.
Ministry of Environment officials determined that wastewater from the Mesco-operated mine had flowed into the nearby O’Tray stream, located roughly 30 meters from the mining site. The stream feeds into the O’Yadav River, potentially spreading the pollution downstream.
Following the inspection, authorities ordered Mesco Gold to immediately stop discharging liquid waste. The company now faces administrative penalties under Cambodia’s Environmental and Natural Resources Code — specifically Articles 156, 173, 287, and 694 — as well as Sub-Decree No. 27 on Water Pollution Control.
The forests and its surrounding land in O’Yadaw district are valuable to the indigenous Jarai community and they claim Mesco Gold is already preventing them from gathering fruit, medicinal plants, rattan and bamboo from the jungle and working in their small upland rice fields.
In addition to halting operations, the firm must pay compensation for environmental damage and any public health impacts. It has also been directed to upgrade its wastewater treatment system to meet national technical standards and comply fully with its approved Environmental and Social Impact Assessment (ESIA) report.
The company is further required to contribute regularly to environmental and social development funds. All wastewater must be transferred from sediment ponds to temporary storage ponds, and additional ponds must be built if necessary. Any leakage points found at the site must be sealed without delay.
To prevent future contamination, Mesco Gold has been instructed to design a drainage system that prevents wastewater from its grinding and screening operations from flowing into natural rainwater channels.
According to the Environment Ministry, nearly 14 million cubic meters of liquid waste from factories and enterprises were prevented from entering public waterways during the first nine months of 2025.
As of September 30, fifty-seven companies and factories have signed contracts committing to full compliance with the Environmental and Natural Resources Code. Forty-six of those have already installed automatic water quality monitoring systems.
Ministry spokesperson Khvay Atitya said that inspection teams have conducted assessments in 54 public areas, treated wastewater at nine sites, and monitored 12 locations considered vulnerable to water pollution across the country. The ministry also operates continuous water quality monitoring in the Chaktomuk River area.
Over the past two years, inspectors have reviewed the liquid waste management systems of 1,549 companies nationwide that have applied for discharge permits.
With additional reporting by Sonny Inbaraj Krishnan.
