June 24, 2022, Vancouver, BC, Canada – At the Mine Water Solutions 2022 conference, Michael Barrett, a project engineer at Knight Piésold Canada, spoke about the hydrometric monitoring network and treated effluent discharge and mixing systems that Knight Piésold designed for the Rainy River Mine (RRM) in northwest Ontario. The conference was held with the theme “Water – Managing for the Future” on June 14–16, 2022 at the Parq Hotel in Vancouver and online.

Barrett delivered a presentation on the paper “Hydrometric Monitoring and Effluent Discharge Mixing in Challenging Natural Conditions” during the mine water management session. The paper was co-authored by Jaime Villaamil and Dr. Violeta Martin of Knight Piésold and Sitotaw Yirdaw, Travis Pastachak, and Garnet Cornell of New Gold Inc. It detailed two systems that were developed for RRM, a gold/silver mine owned by New Gold Inc., to obtain high-quality, real-time discharge measurements and to discharge and mix treated effluent in Pinewood River, enabling RRM to comply with its Environmental Compliance Approval and Permit.

Hydrometric data collection at Pinewood River was frequently affected by backwatering from downstream obstructions and beaver activity that resulted in periods of poor-quality discharge data. The hydrometric monitoring network was upgraded and expanded to improve the quality of data collection that is required for effluent discharge from the mine to Pinewood River.

The treated effluent to be discharged to Pinewood River must meet strict mixing and water quality standards. The passive discharge of treated effluent to Pinewood River, a low velocity receiving environment, may not achieve full mixing without additional measures to promote dilution, so an effluent discharge system using check valve diffusers was designed and constructed. Real-time data from the hydrometric monitoring network is used to inform the effluent discharge strategy on a daily basis.

“Together with RRM and other contributors, we had a remarkable opportunity to design an alternative flow measurement approach while working with complex natural conditions at Pinewood River,” said Barrett. “We continue to support clients with developing water management strategies to enable sustainable mining in challenging environments.”