The federal government is reviewing rules on what metal mines can discharge to watercourses in Canada. It is also considering bringing mines other than metal mines within the ambit of these regulations. The effect could be to increase regulatory certainty but also raise the cost of effluent treatment.

The 2002 Metal Mining Effluent Regulations (MMER) adopted under the federal Fisheries Act are being updated to reflect emerging concerns, notably in the U.S., about the environmental effects of substances such as aluminum, iron, selenium and ammonia that are sometimes present in mining effluent but for which no limits are currently prescribed in the MMER. As part of the review process, the federal government is considering extending the scope of the MMER to include other operations such as diamond, coal and potash mines.

Consultations are underway with a number of stakeholders, including the Mining Association of Canada. In parallel developments, it remains to be seen whether the number of mines subject to the MMER will be affected by amendments to the Fisheries Act announced in 2012 but not yet brought into force which seek to focus application of the Act on places where people fish.