Mantoverde

Mantoverde is an open-pit mine mine located in the province of Chañaral, Atacama Region, 56 kilometers southeast of the city of Chañaral and 100 kilometers north of the city of Copiapó, at an altitude of approximately 900 masl.

Mantoverde currently operates heap and dump run of mine (“ROM”) leaching and conventional SX-EW to treat oxide ore to produce 35,000 to 40,000 tonnes per year of high-purity LME Grade “A” copper cathodes. The mine consists of four pits situated along the Mantoverde fault, each of which contains both sulphide and oxide ores.

The mine owns a state-of-the-art desalination plant, located approximately 40 kilometers west of the mine that supplies all the water required by the operation with 120 liters per second. The plant was expanded to supply 380 liters per second to sustain the mine’s expanded operations after completion of the Mantoverde Development Project (“MVDP”) in late 2023.

The MVDP is expected to increase production from approximately 35,000 tonnes of copper (cathodes only) in 2022 to a run-rate of approximately 120,000 tonnes of copper in H2 2024. A new concentrator plant will treat sulphide material to produce copper concentrate while oxide ores will continue to be treated in the existing SX-EW plant. Mining assumes conventional open pit operations using truck-and-shovel technology.

The MVDP consists of processing sulphide ores in a concentrator with a capacity of 12.3 Mt per year. Construction was completed in late 2023. MVDP is progressing under a lump-sum turn-key engineering, procurement and construction (“EPC”) contract with Ausenco Limited. MVDP’s total capital costs are estimated at $870 million.

Please see here for a virtual site tour of the Mantoverde Development Project: https://vrify.com/decks/12698-mantoverde-development-project

Capstone is currently analyzing the next expansion of the sulphide concentrator. The Company has identified that the desalination plant capacity and major components of the comminution and flotation circuits of the Mantoverde Development Project are capable of sustaining average annual throughput of up to 45,000 tonnes per day with no major capital equipment upgrades. Capstone continues to work with Ausenco’s engineering team to develop the Optimized Mantoverde Development Project (“MVDP Optimized”), including evaluating the costs and timelines of debottlenecking the minor components of the plant to meet the potential throughput target. The Feasibility Study is on track for completion late in H1 2024.

Mantoverde Phase II will evaluate the addition of an entire second processing line, possibly a duplication of the first line, to process some of the additional 77% of resources not utilized by MVDP Optimized. Current activities are focused on understanding the optimum concentrator capacity and mine plan, along with the implications to the timing and permitting for the project.

The Mantoverde deposit is a typical iron oxide–copper–gold (IOCG) deposit located within the Atacama Fault System. It is located in an ancient mining district with numerous Fe, Fe-Cu-Au, Au and Mn deposits in the southern sector of the Atacama Fault System within the Cretaceous iron belt. Copper mineralization is oxidized down to approximately 200 m depth and two types of oxidized copper ores are recognized. The breccias in the sloping fault block contain abundant haematite with brochantite, minor antlerite, chrysocolla, malachite and atacamite, which occur in veinlets, patches and disseminated in the specularite matrix.

Mantoverde District and Near-Mine Exploration – Oxides and Sulphides

Mantoverde has a history of Mineral Reserves and Resources growth through successful exploration. The current Mineral Resource is open at depth in multiple locations along the main Mantoverde, Santa Clara and Montecristo faults. Future drilling programs will focus on deeper high-grade zones and on sulphide areas in the northern portion of the deposit in the underexplored Santa Clara Corridor, which has potential to expand the current Mineral Resource and support conversion into Mineral Reserves.

Mantoverde also has significant potential to develop a larger mining district. Several oxide and sulphide near-mine resource expansion opportunities exist within the mine’s 23 km land package along the Atacama Fault System. District targets identified to date include the Las Animas, Paloma, Las Juntas, San Manuel and Santa Clara targets, north of the current pit design.

2024 Guidance

*Key Assumptions: CLP/USD: 875:1, Gold: $1,850/oz. Production shown on a 100% basis. All figures in USD.