# Relationship history for MSHA mine 4607945

Current hierarchy: **Core Natural Resources Inc → ICG Eastern LLC → Birch River Mine**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Evergreen Mining Company → Birch River Mine; 1990-09-01 to 1992-11-23; source msha-controller-operator-history
- **controller_controls_mine:** Shell Oil Company → Birch River Mine; 1990-09-01 to 1992-11-23; source msha-controller-operator-history
- **controller_controls_operator:** Shell Oil Company → Evergreen Mining Company; 1990-09-01 to 1992-11-23; source msha-controller-operator-history
- **operator_operates_mine:** Evergreen Mining Company → Birch River Mine; 1992-11-24 to 1998-09-01; source msha-controller-operator-history
- **controller_controls_mine:** Zeigler Coal Holding Company → Birch River Mine; 1992-11-24 to 1998-09-01; source msha-controller-operator-history
- **controller_controls_operator:** Zeigler Coal Holding Company → Evergreen Mining Company; 1992-11-24 to 1998-09-01; source msha-controller-operator-history
- **operator_operates_mine:** Evergreen Mining Company → Birch River Mine; 1998-09-02 to 2004-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Horizon Natural Resources Incorporated → Birch River Mine; 1998-09-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Horizon Natural Resources Incorporated → Evergreen Mining Company; 1998-09-02 to 2004-09-30; source msha-controller-operator-history
- **operator_operates_mine:** ICG Eastern LLC → Birch River Mine; 2004-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** International Coal Group Inc (ICG) → Birch River Mine; 2004-10-01 to 2011-06-14; source msha-controller-operator-history
- **controller_controls_operator:** International Coal Group Inc (ICG) → ICG Eastern LLC; 2004-10-01 to 2011-06-14; source msha-controller-operator-history
- **controller_controls_mine:** Arch Resources Inc → Birch River Mine; 2011-06-15 to 2025-01-13; source msha-controller-operator-history
- **controller_controls_operator:** Arch Resources Inc → ICG Eastern LLC; 2011-06-15 to 2025-01-13; source msha-controller-operator-history
- **controller_controls_mine:** Core Natural Resources Inc → Birch River Mine; 2025-01-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Core Natural Resources Inc → ICG Eastern LLC; 2025-01-14 to current/open; source msha-controller-operator-history