Highland Copper Identifies Key Optimization Opportunities Through Detailed Engineering at the Copperwood Project

Executive Summary

• Highland Copper is advancing engineering and metallurgical optimization at its Copperwood project in Michigan, with an Updated Feasibility Study (Updated FS) targeted for release in Q1 2027.
• Key technical improvements include a simplified process plant design increasing copper recovery to 87.6%, evaluation of lower cut-off grades and bulk ore sorting to unlock additional resources, and geotechnical adjustments to optimize mining methods.
• Front-End Engineering and Design (FEED) is progressing toward 40% completion in 2026 to support technical due diligence and position the project for financing.

Key Details

• Updated Feasibility Study (Updated FS): Targeted for Q1 2027; will incorporate revised Mineral Resources and Reserves, optimized mine design and production schedule, updated capital and operating cost estimates, and results of ongoing engineering optimization work.
• Metallurgical & Process Plant Optimization: A simplified process flowsheet (incorporating Jameson cells and a mill-float-mill-float configuration) is expected to increase copper recovery to 87.6% (up from 86.0% in the 2023 FS) at a 25% concentrate grade, while reducing secondary milling requirements, energy/reagent costs, and overall plant footprint.
• Cut-Off Grade Evaluation: Studies are assessing lower cut-off grades based on a long-term copper price of ~US$4.80/lb, with early indications of converting additional Measured and Indicated Mineral Resources into mineable reserves.
• Ore Sorting & UCBS Integration: Bulk ore sorting technology is being evaluated to potentially incorporate the Upper Copper Bearing Sequence (UCBS), which hosts 10.2 million tonnes of Measured and Indicated resources grading 1.1% Cu, currently excluded from the reserve mine plan.
• Current Resource Base: The project hosts 54.2 million tonnes in the Measured and Indicated category at a 1.51% copper grade.
• Geotechnical & Mining Design: Updated geotechnical interpretations may eliminate the previously required 30 cm GLAM beam, enabling optimized room-and-pillar mining heights, pillar dimensions, and sourcing dilution from the mineralized hanging wall rather than the floor.
• Metallurgical Test Work (Sept 2025): Evaluated an MF2 flowsheet with de-sliming, reducing mass reporting to secondary milling by ~25%, cutting comminution energy by 10–13.7%, and potentially lowering operating costs by up to $1.00/tonne milled.
• Tailings Management: Dewatering tests at Responsible Mining Solutions Corp. indicate thickened tailings (~55% solids by mass) are feasible, potentially reducing the Tailings Deposition Facility (TDF) footprint, initial earthwork costs, and environmental impact while improving process recovery water recirculation.
• Engineering & Financing Milestones: FEED is advancing toward 40% completion in 2026 for key work packages, positioning Copperwood for technical due diligence and project financing activities.

Notable Quotes

• Barry O’Shea, CEO: “As we continue our integrated mine plan review against a backdrop of significantly improved long-term consensus copper prices, we are encouraged by the opportunities to further optimize Copperwood through mine design, processing, and engineering enhancements. These initiatives have the potential to strengthen project economics and will be incorporated into the updated feasibility study. With Copperwood advancing toward a construction decision, the Project is entering an increasingly important stage of development at a time when few new copper projects are positioned to come online in the United States in the near term. As demand for domestically sourced critical minerals continues to grow, we believe Copperwood is strategically positioned to play an important role in the future U.S. copper supply chain.”