Metal and diamond mining effluent

ATTENTION! New amendments to the Metal and Diamond Mining Effluent Regulations came into force on June 1, 2021. For more information, click here.

The Metal and Diamond Mining Effluent Regulations help protect Canada’s lakes and rivers by setting strict limits on the quality of effluent that can be discharged by metal and diamond mines. The Regulations authorize the deposit of effluent into water frequented by fish and places referred to in subsection 36(3) of the Fisheries Act. Effluent must meet concentration-based limits for arsenic, copper, cyanide, lead, nickel, zinc, suspended solids, radium 226 and un-ionized ammonia. Effluent must also have a pH that is between a minimum and maximum level, and must not be acutely lethal. The Regulations require effluent testing and reporting, as well as Environmental Effects Monitoring studies.

The Regulations also include an authorization for the use of water frequented by fish for mine waste disposal. Authorization requires an amendment to Schedule 2 of the Regulations. Owners or operators of mines can request an amendment to Schedule 2 of the Regulations, which would designate a water frequented by fish as a Tailings Impoundment Area.

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