# Relationship history for MSHA mine 4601457

Current hierarchy: **Bortz George H Iii → Pittswick Coal Company Inc → Christopher No 5 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:** National Coals Inc → Christopher No 5 Mine; 1950-01-01 to 1973-11-10; source msha-controller-operator-history
- **controller_controls_mine:** National Coals Inc → Christopher No 5 Mine; 1950-01-01 to 1973-11-10; source msha-controller-operator-history
- **controller_controls_operator:** National Coals Inc → National Coals Inc; 1950-01-01 to 1973-11-10; source msha-controller-operator-history
- **operator_operates_mine:** Pittswick Coal Company Inc → Christopher No 5 Mine; 1973-11-11 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Bortz George H Iii → Christopher No 5 Mine; 1973-11-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bortz George H Iii → Pittswick Coal Company Inc; 1973-11-11 to current/open; source msha-controller-operator-history