Regulations Amending the Metal and Diamond Mining Effluent Regulations

What is the purpose of these amendments?

The purpose is to add a requirement for mine owners and operators to demonstrate that saline effluent being deposited into marine waters is not acutely lethal to invertebrate organisms, a condition for mines to maintain their authority to deposit.

What are the key elements of these amendments?

The key change will be a requirement for acute lethality testing using an invertebrate species for deposits of saline effluent to marine environments. Mine owners and operators depositing effluent with a salinity measuring greater than four parts per thousand to a marine environment will need to use the Acartia tonsa test method to demonstrate that their effluent is not acutely lethal.

How do these amendments affect Canadian businesses?

Metal and diamond mining operations will be required to:

When will these changes be implemented?

The amendments to the Metal and Diamond Mining Effluent Regulations (MDMER) with respect to acute lethality testing requirements using the Acartia tonsa test method will come into force on December 1, 2021.

The amendments to correct minor inconsistencies will come into force upon registration of the Regulations.

Where can I get more information?

Metal and diamond mining effluent

Mining and Processing Division
Environmental Protection Branch
Environment and Climate Change Canada
351 St. Joseph Boulevard, 11th Floor
Gatineau QC K1A 0H3

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