The Regulations Amending the Metal and Diamond Mining Effluent Regulations (SOR/2025-139), address the proposed expansion of Evolution Mining Gold Operations Limited’s Red Lake Operations, located roughly six kilometres east of Red Lake, Ontario. The expansion aims to extend the mine’s operational life to 2040 by enlarging the current tailings management facility (TMF), which will reach capacity by August 2025. The enlargement will necessitate the disposal of mine waste in six water bodies that are frequented by fish, resulting in the destruction of 2.39 hectares of fish habitat. Under subsection 36(3) of the Fisheries Act, depositing deleterious substances into waters frequented by fish is prohibited unless specifically authorized by regulation. The Metal and Diamond Mining Effluent Regulations (MDMER) permit the use of fish-frequented water bodies for tailings disposal only if they are listed in Schedule 2 of the MDMER. The amendments therefore designate these six water bodies as tailings impoundment areas (TIAs) under Schedule 2, allowing for mine waste disposal subject to compliance with the regulatory requirements.

Evolution Mining evaluated alternative methods for tailings disposal, following Environment Canada’s Guidelines for the assessment of alternatives for mine waste disposal. Their assessment considered environmental, technical, economic, and socio-economic factors. The selected option scored highest in a multiple accounts analysis and was chosen to minimize environmental harm, including fish habitat destruction and watercourse crossings, while also accounting for Indigenous and community interests related to traditional land and resource use. As part of the regulatory requirements, the proponent must develop a fish habitat compensation plan (FHCP) to offset the habitat loss. The plan must be approved by the Minister of the Environment before any waste can be deposited into the designated water bodies. Evolution Mining is required to provide a financial guarantee, such as a letter of credit valued at approximately $6.22 million over a 10-year period, to ensure the FHCP will be implemented effectively. The FHCP is designed to create about 5.12 hectares of new fish habitat to compensate for the 2.39 hectares lost.

The MDMER set limits on various substances commonly found in mine effluent, including arsenic, copper, cyanide, lead, nickel, zinc, radium-226, unionized ammonia, and total suspended solids, and specify that the pH of effluent must remain within acceptable ranges and must not be acutely lethal to fish or invertebrates. All effluent from the mine, including discharges from TIAs, must meet these standards. Furthermore, mine owners and operators must sample and monitor their effluent, reporting performance annually to the Department of the Environment, to ensure regulatory compliance and to safeguard fish and fish habitat. The amendments are necessary to allow for the continued operation of the Red Lake mine by enabling Evolution Mining to expand the TMF and manage the resulting waste within the designated TIAs.

The amendments aim to balance the continued economic benefits of the mine with protection and compensation measures for fish habitat.

Canada (139/2025) July 2, 2025
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