Highland Copper Announces Updated Process Plant Flow Sheet Demonstrating Increased Copper Recoveries of 87.6% and Reduced Processing Costs

Executive Summary

• Highland Copper reports positive 2025 metallurgical test results for the Copperwood Project, indicating an increase in projected copper recovery to 87.6 % (up from 86 % in the 2023 Feasibility Study) with lower operating costs.
• A redesigned mill‑float‑mill‑float (“MF2”) circuit and optimized reagent scheme are expected to reduce comminution power demand by 10–13.7 % and cut reagent cost by up to $1.00 per tonne milled.
• Glencore Technologies has agreed to provide a performance guarantee on the improved recovery, supporting confidence in moving toward a construction decision in 2026.

Key Details

• Test Program Scope: 45 kinetic rougher/cleaner flotation tests, locked‑cycle and pilot‑scale ultrafine flotation trials; 10 PQ‑size drill holes supplied ≈ 404 kg composite sample.
• Process Circuit Redesign: Adoption of MF2 flowsheet with a de‑sliming stage before secondary milling; primary grind P80 = 80 µm, secondary grind P80 = 38 µm.
• Recovery Performance:
• Rougher kinetic recoveries up to 92.4 % at 4.5 % Cu concentrate grade (baseline 89.7 %).
• Locked‑cycle recovery of 85.8 % at 25 % Cu concentrate grade, with concentrate grade improvement from 25.1 % to 32.9 %.
• Power Consumption: Revised plant draws ≈10.1 MW, a reduction of 10–13.7 % versus the 2023 Feasibility Study design (13.2 MW).
• Reagent Cost Savings: Updated reagent suite reduces cost from $6.50/t to $5.49/t, saving up to $1.00/t milled. Key changes include replacing SIBX with PAX, A‑249 with A‑407, and eliminating D‑250 & NDM.
• Ultrafine Flotation (Jameson Cell): Pilot tests show higher rougher tail mass fraction (32 % vs 21 %) and lower tail Cu grade (0.30 % vs 0.43 %), delivering a rougher concentrate grade of 5.4 % Cu at ~90 % recovery—statistically significant improvement.
• Future Work: Completion of lock‑cycle variability testing (early Q4 2025) and finalization of design criteria before Phase 2 detailed engineering; construction decision targeted for 2026.
• Guarantee: Glencore Technologies will provide a performance guarantee on the projected 87.6 % recovery and 25 % Cu concentrate grade.

Notable Quotes

• “These results represent the culmination of a complete re‑evaluation… The outcome is a robust circuit design…” – Dr. Wynand van Dyk, Project Director.
• “These metallurgical results represent another key milestone as we advance toward a construction decision in 2026.” – Barry O’Shea, President & CEO.