Capstone Copper Publishes 2023 Sustainability Report

Capstone Copper Corp. ("Capstone" or the "Company") (TSX:CS) (ASX:CSC) is pleased to announce that it has published its 2023 Sustainability Report titled "Building Capacity" (the "Sustainability Report" or the "Report"). The Report has been prepared with reference to the Global Reporting Initiative ("GRI") Standards and in accordance with the SASB Metals and Mining Sustainability Accounting Standard. The Report details the Company's performance on material sustainability topics across its operations for the period from January 1 to December 31, 2023.

John MacKenzie, Capstone's CEO, commented, "I am pleased to share our 2023 sustainability report for Capstone Copper. Bringing together the assets and teams of our two predecessor companies has enabled us to realize opportunities of scale, cross-learning and technical excellence as we endeavour to grow responsibly and create a positive impact in the lives of our people and communities."

2023 Sustainability Report Highlights

We continued to build the capacity of our organization to achieve our business and sustainability goals. Some of our highlights from 2023 include:

• Making progress on The Copper Mark: Mantos Blancos and Mantoverde were awarded The Copper Mark.
• Implementing our Sustainable Development Strategy: We launched new cross-site and cross-functional working groups for our Sustainable Development strategic priorities of Climate, Water, Tailings, Biodiversity, and Communities.
• Increasing renewable energy electricity purchases: We secured 100% coverage of our electricity use at Mantos Blancos through renewable energy certificates.
• Enhancing sustainability data disclosures: For the first time, we are publishing a comprehensive sustainability performance data book which contains four years of data for relevant material topics for Capstone as a whole and by site. We are also reporting both market-based and location-based greenhouse gas ("GHG") emissions for the first time.

Some 2022-2023 data trends include:

• Total water withdrawal increased 3% to 19 million cubic metres while the percentage of non-freshwater (other water) withdrawals stayed constant at 22%.
• Total energy use rose by 2% due to increases in fuel use (4%) mainly driven by fuel for capital projects. Electricity use was down 2%. Total market-based GHG emissions decreased by 3% due to the growing share of renewable energy sources in both the Chile and Arizona grids and the purchase of renewable energy certificates for Mantos Blancos.
• Per 200,000 hours in 2023, our Lost Time Injury Frequency Rate (LTIFR) was 0.18 (up from 0.15 in 2022) and our Total Reportable Injury Frequency Rate (TRIFR) was 0.35 (up from 0.21 in 2022). While incident rates were up for the year, we saw an improvement in the last quarter of 2023 as sites focused on incident review and communication as well as monitoring and detection on the ground by supervisors and leadership.
• Capstone's combined workforce grew slightly by 1% to 8,520 (8,425 in 2022) with a 9% increase in number of employees and a 3% decrease in contractors. The proportion of women employees increased from 8% to 9%. Global employee new hire rate (21%) and turnover rate (13%) remained relatively constant which is an indication of a relatively stable employee workforce.

The 2023 Sustainability Report is available on Capstone's website at https://capstonecopper.com/responsibility/

About Capstone Copper Corp.

Capstone Copper Corp. is an Americas-focused copper mining company headquartered in Vancouver, Canada. We own and operate the Pinto Valley copper mine located in Arizona, USA, the Cozamin copper-silver mine located in Zacatecas, Mexico, the Mantos Blancos copper-silver mine located in the Antofagasta region, Chile, and 70% of the Mantoverde copper-gold mine, located in the Atacama region, Chile. In addition, we own the fully permitted Santo Domingo copper-iron-gold project, located approximately 30 kilometres northeast of Mantoverde in the Atacama region, Chile, as well as a portfolio of exploration properties in the Americas.

Capstone Copper's strategy is to unlock transformational copper production growth while executing on cost and operational improvements through innovation, optimization and safe and responsible production throughout our portfolio of assets. We focus on profitability and disciplined capital allocation to surface stakeholder value. We are committed to creating a positive impact in the lives of our people and local communities, while delivering compelling returns to investors by responsibly producing copper to meet the world's growing needs.

Further information is available at www.capstonecopper.com

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This document may contain "forward-looking information" within the meaning of Canadian securities legislation and "forward-looking statements" within the meaning of the United States Private Securities Litigation Reform Act of 1995 (collectively, "forward-looking statements"). These forward-looking statements are made as of the date of this document and the Company does not intend, and does not assume any obligation, to update these forward-looking statements, except as required under applicable securities legislation.

Forward-looking statements include, but are not limited to, statements with respect to the estimation of Mineral Resources and Mineral Reserves, the success of the underground paste backfill and tailings filtration projects at Cozamin, the timing and cost of the Mantoverde Development Project ("MVDP"), the timing and results of the Optimized Mantoverde Development Project ("MV Optimized FS") and Mantoverde Phase II study, the timing and results of PV District Growth Study (as defined below), the timing and results of Mantos Blancos Phase II Feasibility Study, the timing and success of the Mantoverde - Santo Domingo Cobalt Feasibility Study, the timing and results of the Santo Domingo FS Update and success of incorporating synergies previously identified in the Mantoverde - Santo Domingo District Integration Plan, the timing and results of exploration and potential opportunities at Sierra Norte, the realization of Mineral Reserve estimates, the timing and amount of estimated future production, the costs of production and capital expenditures and reclamation, the timing and costs of the Minto obligations and other obligations related to the closure of the Minto Mine, the budgets for exploration at Cozamin, Santo Domingo, Pinto Valley, Mantos Blancos, Mantoverde, and other exploration projects, the timing and success of the Copper Cities project, the success of our mining operations, the continuing success of mineral exploration, the estimations for potential quantities and grade of inferred resources and exploration targets, our ability to fund future exploration activities, our ability to finance the Santo Domingo development project, environmental and geotechnical risks, unanticipated reclamation expenses and title disputes, the success of the synergies and catalysts related to prior transactions, in particular but not limited to, the potential synergies with Mantoverde and Santo Domingo, the anticipated future production, costs of production, including the cost of sulphuric acid and oil and other fuel, capital expenditures and reclamation of Company's operations and development projects, our estimates of available liquidity, and the risks included in our continuous disclosure filings on SEDAR+ at www.sedarplus.ca. The impact of global events such as pandemics, geopolitical conflict, or other events, to Capstone is dependent on a number of factors outside of our control and knowledge, including the effectiveness of the measures taken by public health and governmental authorities to combat the spread of diseases, global economic uncertainties and outlook due to widespread diseases or geopolitical events or conflicts, supply chain delays resulting in lack of availability of supplies, goods and equipment, and evolving restrictions relating to mining activities and to travel in certain jurisdictions in which we operate. In certain cases, forward-looking statements can be identified by the use of words such as "anticipates", "approximately", "believes", "budget", "estimates", "expects", "forecasts", "guidance", "intends", "plans", "scheduled", "target", or variations of such words and phrases, or statements that certain actions, events or results "be achieved", "could", "may", "might", "occur", "should", "will be taken" or "would" or the negative of these terms or comparable terminology.

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Daniel Sampieri, Director, Investor Relations & Strategic Analysis
437-788-1767
dsampieri@capstonecopper.com

Michael Slifirski, Director, Investor Relations, APAC Region
61-412-251-818
mslifirski@capstonecopper.com