Exhibit 99.1 Core Natural Resources Reports First Quarter 2025 Results Returns $106.6 million to investors via share buybacks and quarterly dividend Increases merger-related synergies target by 10$125 and $150 million Makes excellent progress towards full resumption of operations at Leer South Executes well-timed capital market transactions establishing target capital structure while boosting liquidity, extending maturities, reducing interest rates, and increasing financial flexibil ...