Community Update Q4 2022

An update from the Mount Polley Team

At the end of 2022, we reflected on a year of progress and improvement as our dedicated team worked tirelessly to refine our standard operating procedures and management systems. These efforts paid off, as we witnessed smoother mine operations throughout the final quarter of 2022. We are proud to report that on several occasions, we even exceeded our production targets – a testament to the hard work and commitment of our exceptional workforce and refined operations.

In addition to surpassing production goals, Mount Polley achieved a significant milestone by shipping a load of concentrate to overseas markets. This accomplishment marks a new chapter for us as we work to contribute to the global supply of critical minerals. We believe in the importance of producing these essential resources, not just for today, but also for the future.

Figure 1 – Mount Polley Mine looking north from the Tailings Storage Facility.

COVID-19

Mount Polley employees continue to take additional precautions to minimize the risks of COVID-19 transmission.

Community

At Mount Polley, we recognize the importance of local partnerships and the positive impact they have on our shared prosperity. We are committed to uplifting our neighbouring communities and continue to utilize local businesses to the maximum extent possible.  Whether its sourcing consumables – such as parts or safety equipment – or seeking professional services – such as accommodation – we prioritize collaboration with local companies to do business.  Now that Mount Polley is in full operation we aim to continue to support the local community and contribute to its development and the growth and well-being of the region.

Site Operations

Pit Operations

Springer Pit development is on track with a focus on materials handling.  Ore and waste delineation is critical for planned production and forecasted mining and milling rates. Non-acid generating (NAG) and potentially acid generating (PAG) rock are identified and managed in accordance with the relevant management plans. Tailings remain in the Springer Pit and plans for their removal are fast approaching. The Cariboo Pit is partially flooded and will serve as a temporary water storage site for in-pit surplus water and the Wight Pit continues to serve as the site wide surplus water storage facility.  Our commitment to responsible practices and efficient mining guides our operations.

Figure 2 – Column flotation cells floating concentrate.

Assay Lab

The work the Mount Polley assay lab does in analyzing samples leads to real data. That data is the grades of the payable minerals in those samples and which will guide decisions. For example, which ore in the pit will feed the mill, or placing a dollar value on ore that was processed through the mill.  A quick assay might help correct a poorly running circuit in the mill which, in turn, will benefit Mount Polley’s bottom line.  Test work assessed by assay results can improve mineral recovery, potentially extending the mine’s lifespan. Additionally, the assay lab’s analysis confirms the concentrate quality sold to the smelter, which directly impacts the mine’s financial prosperity and supports Mount Polley’s workforce. The valuable work of the assay lab team and their commitment to delivering accurate data is instrumental in driving our operations forward.

Exploration Update

Exploration plans for infill drilling within the Springer Pit are underway for Q1 2023.

Permitting Activities

Current permitting activities underway in Q4 included the following:

Environmental Monitoring Update

Recent and ongoing monitoring activities completed in Q4:

• Weekly Water Treatment Plant (WTP) water quality sampling including weekly/monthly/quarterly toxicity sampling.
• Monthly water quality sampling at Hazeltine Creek.
• Monthly & quarterly water quality sampling of surface & mine affected waters including groundwater and mine seepage.
• Water quality monitoring in Quesnel, Bootjack and Polley lakes.
• Site wide flow monitoring, to cease once ice forms in waterways.
• Wildlife monitoring, camera traps.
• Specialized biological monitoring (benthic/invertebrate, tissue, periphyton, plankton etc.).
• Water quality sampling and monitoring of Springer, Cariboo and Wight pits.
• Monthly/quarterly site inspections including waste management.
• Reporting—monthly, quarterly, annual.
• Comprehensive Environmental Monitoring Plan (CEMP) development/revision.

Environmental monitoring is conducted in accordance with the Environmental Management Act (EMA) Permit 11678 and the BC-ENV ministry approved CEMP requirements.

Water Treatment Plant (WTP) Performance Update

The Veolia Actiflo® water treatment plant operated nearly continuously throughout the quarter.  High discharge volumes were possible due to the operation of a rental mobile water treatment plant (MWTP) in addition to the main plant.  Although there were intermittent periods of low influent volumes, higher than historic volumes were successfully treated throughout the quarter. The treatment plant benefited from high-quality influent (E19) sources from the Cariboo and Springer Pits, as well as their natural pit treatments, allowing for increased throughput.

Figure 3 – Wight Pit Lake.  Pit lake monitoring is ongoing.

Figure 4 – Total copper concentrations at the water treatment plant.  The purple dots represent total copper as measured in the temporary mobile plant.  HAD-3 represents effluent values and E19 represents influent values.

Figure 5 – The 52-week rolling average comparing total copper concentrations to the Numeric Performance Metric (NPM) permit target of 0.012mg/L.

Figure 6 – The 52-week rolling average comparing total copper concentrations to the Numeric Performance Metric (NPM) permit target of 0.012mg/L.

Hazeltine and Edney Creek Remediation

Environmental monitoring activities are ongoing in the remediated areas and planning is underway for the completion of the project.

Reclamation Update

An update to Mount Polley’s reclamation plan was completed near the end of 2022.  The Mine Plan and Reclamation Program Update 2022 “provides an overview of planned mine operations and reclamation and closure objectives and strategies for all permitted Mine units, and associated liability cost estimates for their execution. The MPMC reclamation program is designed to meet the environmental protection and reclamation requirements of all applicable provincial and federal legislation, including:

• The British Columbia (BC) Mines Act.
• The Health, Safety and Reclamation Code for Mines and British Columbia.
• The Environmental Management Act (EMA).
• The Canadian Fisheries Act (including the annexed Metal and Diamond Mining Effluent Regulations; MDMER).”

The plan includes specific reclamation objectives and approaches to meet end land use goals beyond the life of the mine.  The following objectives have been set within the plan:

“The main objective of the reclamation program is to return all areas that have been disturbed by mining operations (except pit walls) to equivalent or greater land capability than existed prior to mining, on an average property basis. To help achieve this overarching goal, an End Land Use Plan has been developed, which focusses on ecosystem rehabilitation as the main goal with a target towards ecosystems that occurred prior to disturbance.

The End Land Use Plan also estimates shifts in the end land use objectives over time as the ecological trajectories of the ecosystem evolve. This allows for end land use planning to be considered over the long-term and considers that a variety of end land uses can occur on the landscape over different temporal scales. To achieve successful closure of the Mine Site, the following objectives must be achieved:

• Long-term stability of engineered structures, including the Rock Disposal Sites (RDSs), Tailings Storage Facility (TSF) and open pits, as well as all exposed erodible materials.
• Removal and proper disposal of access roads, structures, and equipment not required after the Mine Site closes.
• Sufficient cover soil (e.g., reclamation material) to achieve the desired target ecosystems on the post-closure landscape.
• Geochemical stability of RDSs, open pits, the TSF, and all other major components of the Mine Site in the post-closure landscape.
• Long-term preservation of water quality within and downstream of decommissioned operations.
• A water balance that meets the requirements for a functional landscape that aligns with the targeted end land use.
• Natural integration of disturbed lands into surrounding landscape, and restoration of the natural appearance of the area after mining ends, to the extent practicable.
• Self-sustaining vegetation covers established, consistent with the end land uses and desired ecosystems.
• Use of reclaimed ecosystems by their desired stakeholders (e.g., recreational users, wildlife, and traditional use practitioners).

Once these aspects are in place, flexibility exists to modify ecosystem composition, patch size, and vegetation mosaic and to provide additional structural components, as desired. By reclaiming disturbed land to stable, functioning, and locally appropriate ecosystems that can reasonably be expected to thrive on a specific landform or location, a variety of end land use objectives can also be met.”

These types of plans are critical to long term landscape level sustainability and are a regulatory requirement for modern mining in BC.  BC reclamation legislation is designed “to ensure that modern mine sites in B.C. do not leave an ongoing legacy or require public funds for clean-up activities.”

(BC EMLI, www2.gov.bc.ca, 2022)

MPMC Events

Events in 2022:

• January 19, 2022: •Xatśūll Community Engagement Meeting
• January 27, 2022: Public Liaison Committee (PLC) Meeting via conference call
• March 17, 2022: Williams Lake First Nation Career Fair
• March 28, 2022: Likely Community Engagement Meeting
• April 7, 2022: Public Liaison Committee Meeting
• May 4, 2022: Williams Lake First Nations Tour
• July 7, 2022: Public Liaison Committee Meeting and tour at the mine
• Oct. 6, 2022: Public Liaison Committee Meeting and tour at the mine
• Oct. 24, 2022: Williams Lake First Nation Implementation Committee Meeting

Resources

mountpolley.com

imperialmetals.com

BC Mine Information Page: https://mines.nrs.gov.bc.ca/

BC Ministry of Environment Natural Resource and Enforcement Database: https://a100.gov.bc.ca/pub/ocers/searchApproved.do?submitType=menu

Interested applicants may send their resume and cover letter to: hr@mountpolley.com

For questions regarding the Community Update, please email Gabriel Holmes at gabriel.holmes@mountpolley.com