Great Bear Resources Ltd. - Environmental Compliance Approval (sewage)

The ministry reviewed all comments received through the ERO and also consulted with Indigenous communities that may be impacted. Following the 45-day ERO comment period, additional time was given to potentially impacted Indigenous communities to review supporting materials and provide their comments.

The main concerns raised were regarding the following:

• The risks of sulphate discharge causing mercury methylation
• Wastewater impacts to receiving rivers and the environment
• Environmental effects from metal leaching and acid rock drainage
• Screening and scoping of parameters of potential concern
• Design of the water treatment plant, and its ability to treat effluent discharge from the activity
• Potential impacts to fish populations
• Concerns regarding the company's compliance record in another jurisdiction

All comments received were carefully reviewed, and, where appropriate, were considered in the design of sewage works by the applicant’s consultant and in the ministry’s decision on whether or not to proceed with this proposal. Our review is not only based on the materials submitted by the proponent, but also available science and data and the feedback received from Indigenous communities.

The following points contributed to the Ministry’s decision to issue the ECA:

1. The Ministry’s review and decision-making process aligns with applicable environmental legislation and policies, which are designed to uphold Ontario’s high environmental standards. When assessing applications for environmental permissions, the ministry considers a variety of factors, including feedback received through consultation with Indigenous communities and the public. These decisions are informed by an internal technical review process grounded in the ministry’s Statement of Environmental Values, which reflects the Principle of Environmental Management, the Principle of Pollution Reduction/Environmental Restoration, the Principle of Strategic Management, and the importance of providing opportunities for consultation.
2. The ministry has adopted a conservative approach to address sulphate discharge. Effluent limits and discharge criteria for sulphate have been established in the approval so that any discharge must meet the background concentration of the receiving environment at the edge of a short mixing zone. Effluent discharge will not be permitted unless the Chukuni River is flowing at a minimum of 1.8 m³/s. To address the possible methylation of mercury caused by sulphate discharges, the ECA requires the monitoring of sulphate, total mercury, and methylmercury, along with a suite of other parameters, within the mixing zone, in the discharge, in receiving waters, and in groundwater. GBR will be required to implement an Aquatics Effects Monitoring Plan that incorporates monitoring of sediment, fish tissue, and benthic invertebrate with a focus on assessing potential increases in mercury methylation associated with the effluent and includes triggers for mitigation.
3. GBR prepared a Metal Leaching and Acid Rock Drainage (ML-ARD) Assessment Report for rock and overburden, which will require annual updating to identify the latest environmental trends in the area. The ECA requires the implementation of a ML-ARD Monitoring Plan, comprehensive monitoring, and submission of annual ML-ARD assessment updates. The ECA also requires the company to ensure early segregation, containment, and monitoring of materials that could leach metals. Mine rock and ore stockpile areas are required to be lined with impermeable liners, and runoff and seepage are directed to engineered collection systems and treatment by a multi-stage treatment plant. To ensure treated effluent does not cause harmful metal loading in the Chukuni River, the ECA sets discharge limits for leachable metals, including arsenic, copper, nickel, lead, and zinc.
4. To screen and scope parameters of potential concern, baseline studies were conducted including surface water, groundwater, and contact water; and the ministry’s Procedure B-1-5 was applied by GBR using an assimilative capacity assessment of the receiving water to develop receiver-based effluent limits. The ECA includes comprehensive monitoring for a comprehensive suite of parameters, including trigger criteria to initiate mitigation if required based on monitoring.
5. Regarding the wastewater treatment system, it includes sediment and settling ponds, metal precipitation and clarification units, a coagulation unit, ultrafiltration (UF) membranes, biological ammonia removal, secondary metal precipitation and clarification stages, geotubes for sludge management, and a final polishing step; this treatment train is designed to reliably meet effluent limits for Total Suspended Solids (TSS), unionized ammonia, copper, nickel, lead, zinc, arsenic, total phosphorus, and pH. The design also includes extra water storage to manage water during extreme weather. The ECA imposes requirements for contingency plans and procedures for dealing with potential issues with the water treatment plant, including requiring plans to address any deviations from the predicted influent water quality.
6. To address potential impacts to fish, the proposed ECA includes conditions which will require GBR to conduct acute lethality tests of the effluent during periods of discharge. If acute lethality is detected, there are actions the company must take to determine the cause or source of the acute toxicity and take corrective action (investigation, mitigation, and continued testing). Additionally, the company developed an Aquatics Effects Monitoring Plan that incorporates monitoring of sediment, fish tissue, and benthic invertebrates with a focus on assessing potential increases in mercury methylation associated with the project, and any associated increases in bioaccumulation. Fish tissue monitoring data will be compared against a risk-based guidelines for both total mercury and methylmercury.
7. Ontario has a robust framework for ensuring environmental compliance including inspections and enforcement by District Office staff. GBR is required to comply with all applicable legislative and regulatory requirements in Ontario including the legally enforceable ECA; and District Office staff have numerous tools for addressing non-compliances.