Rosemary L. Klein, who serves as senior vice president, CLO & Corporate Secretary at Core Natural Resources, Inc. (EXCHANGE:CNR), completed two sales of company common stock on March 19, 2026, disposing of a total of 15,000 shares for aggregate proceeds of $1,603,100.
According to a Form 4 filed with the Securities and Exchange Commission, the first transaction involved 10,000 shares sold at $105.00 per share, producing $1,050,000 in proceeds. A second transaction that day recorded the sale of 5,000 shares at $110.62 per share, yielding $553,100.
Following these dispositions, Klein retained direct ownership of 53,679 shares of Core Natural Resources, which includes 11,045 unvested restricted stock units. The Form 4 provides the details of the trades and the resulting shareholdings.
Mine safety incident and regulatory action
In a separate disclosure, Core Natural Resources reported a temporary shutdown at its Mountaineer II mine site operated by its subsidiary, Mingo Logan Coal LLC. The Mine Safety and Health Administration issued an imminent danger order under section 107(a) of the Federal Mine Safety and Health Act of 1977 after detecting elevated methane concentrations in a section of the mine.
The company said it took immediate steps to lower methane levels, restoring concentrations in the affected area to acceptable readings. Following those corrective measures, MSHA terminated the 107(a) order. Core Natural Resources reported that no injuries or illnesses were associated with the incident.
The sequence of events — the SEC-filed insider stock sales and the mine operational pause prompted by the MSHA order — were disclosed in regulatory filings and company statements. The company noted actions to bring the affected mining section back into compliance, and the MSHA closed out the imminent danger order after the area met acceptable methane levels.
Contextual notes
The transaction details, current shareholdings, and the regulatory action at Mountaineer II are documented in filings and company notices. The MSHA order was issued specifically under section 107(a) and subsequently terminated following remedial measures; there were no reported injuries or illnesses connected to the event.