TORONTO (miningweekly.com) – The British Columbia provincial government on Tuesday issued miner Imperial Metals with an official warning after an inspection last week found the breached tailings facility of the Mount Polley copper/gold mine was still leaking effluent a month after a disastrous dam failure released millions of litres of mine waste into the pristine natural environment.

The province’s Environment Ministry inspected the mine on Thursday and found it to be noncompliant with the Environmental Management Act (EMA) because effluent was still discharging from the tailings storage facility into Hazeltine creek.

The Ministry issued an advisory to the Mount Polley Mining Corporation, directed at mine manager Dale Reimer, directing the company to take prompt action to abate all discharges from the tailings storage facility into the receiving environment.

The Ministry added that while it appreciated Imperial’s efforts to undertake significant works at and around the site of the failure, and understanding that there were challenges to working safely at or below the site of the breach, it felt that “more action could be taken to provide a greater degree of environmental protection in a more timely manner”.

Discharges had subsequently stopped since the last inspection, but Ministry staff were concerned that future events of rain would trigger more discharges.

Imperial was directed to install sediment-control systems and ensure abatement capacity was designed and built to handle a one-in-ten-year, 24-hour rainfall event.

The advisory was the first step of an escalating enforcement response to a violation of the Environmental Management Act.

In the early hours of August 4, a tailings pond breach occurred at the Mount Polley mine in south-central British Columbia, near the town of Likely. Imperial initially reported that the breach released about ten-million cubic metres of effluent into the Polley and Quesnel lakes.

The company later revised the report to about 17-million cubic metres of water and eight-million cubic metres of tailings/materials discharged into the Polley and Quesnel lakes.

The Ministry of Environment had previously issued a pollution abatement order on August 5, to the Mount Polley Mine Corporation, and would oversee implementation of the responsible party's action plan to ensure the information meets the Ministry's needs for assessing potential environmental impacts and monitoring ecosystem recovery.