---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-25-151981"
form_type: "8-K"
ticker: "CNR"
cik: "0001710366"
company_name: "Core Natural Resources, Inc."
filed_at: "2025-06-30T23:59:59+00:00"
generated_at: "2026-05-18T13:25:03.101978+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# Core Natural Resources updates Leer South restart; delay of up to 4 months, insurance recovery >$100M

## Summary
- Mine re-entered June 10; ventilation restored, longwall components in good condition.
- On June 26, elevated CO levels forced evacuation and resealing of affected area.
- Plan aims to reposition and restart longwall within next four months (Q4 2025).
- Reiterates 2025 coking coal sales volume guidance despite delayed restart.
- Expects Leer South-related insurance recoveries in excess of $100 million.

## SEC filing metadata
- accession: 0001193125-25-151981
- form_type: 8-K
- ticker: CNR
- cik: 0001710366
- company_name: Core Natural Resources, Inc.
- filed_at: 2025-06-30T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 7.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1710366/000119312525151981/0001193125-25-151981-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1710366/000119312525151981/d82152d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-25-151981
- JSON: https://secwatch.observer/filing/0001193125-25-151981.json
- Plain text: https://secwatch.observer/filing/0001193125-25-151981.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.