# Relationship history for MSHA mine 4002521

Current hierarchy: **A J  Smith Jr → A J Smith Jr → A J Smith 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** A J Smith → A J Smith Mine; 1979-01-01 to 1980-05-25; source msha-controller-operator-history
- **controller_controls_mine:** Smith A J Sr → A J Smith Mine; 1979-01-01 to 1980-05-25; source msha-controller-operator-history
- **controller_controls_operator:** Smith A J Sr → A J Smith; 1979-01-01 to 1980-05-25; source msha-controller-operator-history
- **operator_operates_mine:** A J Smith Jr → A J Smith Mine; 1980-05-26 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** A J  Smith Jr → A J Smith Mine; 1980-05-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** A J  Smith Jr → A J Smith Jr; 1980-05-26 to current/open; source msha-controller-operator-history