Capstone approves Mantoverde pyrite plant

Canada’s Capstone Copper has approved a $45 million pyrite recovery project at its Mantoverde copper operation in Chile that will cut the mine’s sulphuric acid consumption by around 90,000 t/y, the company said in its second-quarter results on 30 July. The Board of Directors approved the Mantoverde Pyrite Augmentation (MVPA) project in July, with formal sanctioning expected in the third quarter of 2026 subject to approval from Mantoverde’s joint venture partner. The project is expected to be completed in early 2028.

MVPA will incorporate a pyrite recovery circuit into the existing Mantoverde concentrator plant. Pyrite (iron sulphide) will be recovered and concentrated from the tailings stream, then conditioned and transferred to the existing heap leach process. Based on 10 million t/y of oxide ore leaching at Mantoverde’s heap leach facility, the project is expected to reduce sulphuric acid requirements by approximately 20% — an average of 90,000 t/y of sulphuric acid — while also increasing cathode copper production by an average of about 3,500 t/y. At an assumed CFR Chile sulphuric acid price of $200 to $450 per tonne, Capstone estimates the acid cost savings at $18 million to $40 million per year. Capital cost of $45 million is expected to be incurred in 2027, with the incremental processing operating cost estimated at $0.22 per tonne of sulphide ore processed.