Dome Mine: Two Ponds Added as TIAs

Summary#

The final rule, Regulations Amending the Metal and Diamond Mining Effluent Regulations, adds two small water bodies near Timmins, Ontario, to Schedule 2 so they can be used as tailings impoundment areas for the Dome Mine. The regulation was registered on June 21, 2024 and authorizes mine waste disposal that will remove 2.61 hectares of fish habitat, but requires a compensation plan that will create 3.26 hectares of new habitat.

What it does#

• Lists two specific waters near Timmins (one unnamed pond and one small mapped area) in Schedule 2 of the Metal and Diamond Mining Effluent Regulations (MDMER), designating them as tailings impoundment areas (TIAs).
• Authorizes the deposit of mine waste into those waters for the Dome Mine’s expansion and seepage collection work carried out by Newmont Corporation.
• Requires the proponent to prepare and get approval for a Fish Habitat Compensation Plan (FHCP) under section 27.1 of the MDMER before any mine waste is placed in the listed waters.
• Requires an irrevocable financial guarantee (letter of credit or equivalent) to cover FHCP costs, estimated at $853,695 (undiscounted) over 2024–2028; the present-value estimate in the regulatory analysis is $847,201.
• Identifies the affected site as roughly 7 km east of Timmins, Ontario, and notes the mine redevelopment will likely extend operations to 2035.

Who's affected#

• Newmont Corporation (the mine owner) — needs to implement the FHCP and post the financial guarantee.
• Local fish and aquatic habitat — the rule covers two ponds that support species such as brook stickleback and northern redbelly dace.
• Nearby Indigenous communities and rights-holders that were consulted, including Mattagami First Nation, Matachewan First Nation, Flying Post First Nation, Taykwa Tagamou Nation, Apitipi Anicinapek Nation, and the Métis Nation of Ontario (Region 3).
• Federal and provincial regulators, including Environment and Climate Change Canada (the Department of the Environment) and the Department of Fisheries and Oceans (DFO), which will review and monitor the FHCP.
• Local residents and people who use nearby waters for recreation or traditional activities — they may notice changes to small local ponds and increased monitoring or construction activity.

Why it matters#

• It makes a specific, limited trade-off: the government allows the mine to destroy 2.61 hectares of fish habitat in order to improve tailings management, while requiring offsetting work expected to create 3.26 hectares of habitat. That is intended to produce a small net gain in habitat area (about 0.65 hectares).
• The rule lets the mine build a seepage collection network and raise dams to reduce uncontrolled seepage — a measure framed as improving environmental performance around the tailings area.
• There is a direct cost to the company to build and monitor the compensation measures (about $853,695), backed by a financial guarantee so public authorities can ensure the work is completed.
• Local Indigenous groups raised concerns and asked for limits and monitoring; some supported the authorization after consultations. The item records ongoing engagement but also shows differing views among communities.
• For nearby people, the practical effects are mainly local: construction and monitoring near the No. 6 Tailings Management Area, changes to two small ponds, and long‑term oversight by federal and provincial authorities.