New Gold Inc. - Environmental Compliance Approval (sewage)

This proposal is for an amendment to Environmental Compliance Approval No. 2290-CAVKGN for industrial sewage works serving the Rainy River Mine located at 5967 Highway 11/71, in the Township of Emo, Ontario.

New Gold Inc. is proposing to amend its existing Environmental Compliance Approval to increase the total effluent treatment capacity at the Rainy River Mine to 59,000 cubic metres per day and the authorized discharge to the Pinewood River to 126,000 cubic metres per day. The proposed increase is required to manage site-wide water volumes and ensure ongoing regulatory compliance as mine operations expand.

Scope of Proposed Changes:

• increase maximum effluent treatment capacity to 59,000 cubic metres per day
• increase maximum discharge limit to the Pinewood River to 126,000 cubic metres per day
• expand the Domestic Sewage Treatment Plant to support up to 900 site personnel
• install a new septic system to serve an additional 200 personnel at the Underground Laydown Area

Rationale:

The amendment is driven by long-term mine water balance forecasts, which show that higher treatment and discharge capacities are necessary to control pond volumes within the Tailings Management Area. This requirement becomes more pronounced after 2029 due to increased pore water release from the tailings. Additionally, with the ramp-up of underground operations, the mine requires expanded sewage treatment infrastructure to support the projected workforce.