# Relationship history for MSHA mine 1506259

Current hierarchy: **Mc Dowell Enterprises Inc → Unit Train Coal Sales Inc → No 2 Strip**

- 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:** Medlin Coal Company Inc → No 2 Strip; 1950-01-01 to 1974-09-01; source msha-controller-operator-history
- **controller_controls_mine:** Medlin John D → No 2 Strip; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Medlin John D → Medlin Coal Company Inc; 1950-01-01 to 1974-09-01; source msha-controller-operator-history
- **operator_operates_mine:** Unit Train Coal Sales Inc → No 2 Strip; 1974-09-02 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mc Dowell Enterprises Inc → No 2 Strip; 1974-09-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mc Dowell Enterprises Inc → Unit Train Coal Sales Inc; 1974-09-02 to current/open; source msha-controller-operator-history