# Relationship history for MSHA mine 1502725

Current hierarchy: **Wooton Sam → Sam Wooton Coal Company → No 2 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:** Bryan Keith Coal Company Inc → No 2 Mine; 1950-01-01 to 1976-07-05; source msha-controller-operator-history
- **controller_controls_mine:** Keith Bryan Coal Company Inc → No 2 Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Keith Bryan Coal Company Inc → Bryan Keith Coal Company Inc; 1950-01-01 to 1976-07-05; source msha-controller-operator-history
- **controller_controls_mine:** Wooton Sam → No 2 Mine; 1975-10-02 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Sam Wooton Coal Company → No 2 Mine; 1976-07-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Wooton Sam → Sam Wooton Coal Company; 1976-07-06 to current/open; source msha-controller-operator-history