X0609 4 2026-03-18 0001710366 Core Natural Resources, Inc. CNR 0001620612 Brock James A 275 TECHNOLOGY DRIVE, SUITE 101 CANONSBURG PA 15317 true true false false Executive Chair and CEO false Common stock, par value $0.01 per share 2026-03-18 4 S false 40760 101.15 D 100000 I By SLAT-1 Common stock, par value $0.01 per share 24440 I Lee Ann Brock Trust Common stock, par value $0.01 per share 117398 I By GRAT-1 Common stock, par value $0.01 per share 266975 D This sale was made in connection with a long-term strategy for estate planning purposes. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $100.62 to $101.57, inclusive. The reporting person undertakes to provide to Core Natural Resources, Inc., any security holder of Core Natural Resources, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnote (2) to this Form 4. Of the 266,975 shares reported, 44,640 shares are unvested restricted stock units. /s/ Rosemary L. Klein, Attorney-in-Fact for James A. Brock 2026-03-19