Imperial Metals has announced that the breach of a tailings pond dam at its Mount Polley copper and gold mine in British Columbia has been stabilised and the release of tailings has been controlled.
The dam, which breached on Monday, discharged large quantities of muddy water and tailings in to the surrounding areas, prompting the Cariboo Regional District to issue a water use ban.
The authorities warned locals not to consume or bathe in the water and not allow pets or livestock to drink the water.
Imperial Metals has stated that the gray sludge released does not generate acids and that it contains alkaline with an average ph of 8.5. The details of discharge quantities are yet to be determined.
Imperial Metals said: "Our first priority is the health and safety of our employees and neighbours, and we are relieved no loss of life or injury have been reported.
"We are deeply concerned and are working to mitigate immediate effects and understand the cause."
Following the incident, the company has placed its mine on care and maintenance.
Meanwhile, British Columbia Minister of Energy and Mines Bill Bennett said: "In the early morning of August 4, 2014, the tailings pond dam at the Mount Polley mine site breached and released an estimated ten million m³ of water and 4.5 million m³ of fine sand into Polley Lake.
"Hazeltine Creek flows out of Polley Lake, and the flow may have continued into Quesnel Lake.
"This is a serious incident that should not have happened. We are devoting every appropriate resource working with local officials to clean up the site, mitigate any impacts to communities and the environment, and investigate the cause of the breach."
Some of the waterways that are expected to have been affected by the breach include Quesnel Lake, Polley Lake, Hazeltine Creek, Cariboo Creek, and the Quesnel and Cariboo Rivers systems up to the Fraser River.
"The Ministry of Environment is on-site conducting water tests to determine the full extent of potential environmental impacts," Bennett added.
"Water sampling took place the evening of August 4. Samples have been sent for analysis today, with results expected later this week."