# Relationship history for MSHA mine 1500776

Current hierarchy: **A F & J Coal Company → A F & J Coal Company → No 1 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:** M & C Coal Company → No 1 Mine; 1950-01-01 to 1974-05-01; source msha-controller-operator-history
- **controller_controls_mine:** M & C Coal Company → No 1 Mine; 1950-01-01 to 1974-05-01; source msha-controller-operator-history
- **controller_controls_operator:** M & C Coal Company → M & C Coal Company; 1950-01-01 to 1974-05-01; source msha-controller-operator-history
- **operator_operates_mine:** A F & J Coal Company → No 1 Mine; 1974-05-02 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** A F & J Coal Company → No 1 Mine; 1974-05-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** A F & J Coal Company → A F & J Coal Company; 1974-05-02 to current/open; source msha-controller-operator-history