# Relationship history for MSHA mine 1510885

Current hierarchy: **Day Linda → Da-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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Tucker J O → No 1 Mine; 1977-05-01 to 1979-05-15; source msha-controller-operator-history
- **operator_operates_mine:** Commonwealth Excavating Company Inc → No 1 Mine; 1977-11-01 to 1978-12-19; source msha-controller-operator-history
- **controller_controls_operator:** Tucker J O → Commonwealth Excavating Company Inc; 1977-11-01 to 1978-12-19; source msha-controller-operator-history
- **operator_operates_mine:** Blackmont Mining Company → No 1 Mine; 1978-12-20 to 1982-12-15; source msha-controller-operator-history
- **controller_controls_mine:** Williamson Charles O → No 1 Mine; 1978-12-20 to 1982-12-15; source msha-controller-operator-history
- **controller_controls_operator:** Williamson Charles O → Blackmont Mining Company; 1978-12-20 to 1982-12-15; source msha-controller-operator-history
- **controller_controls_mine:** Day Linda → No 1 Mine; 1982-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Da-Coal Company → No 1 Mine; 1982-12-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Day Linda → Da-Coal Company; 1982-12-16 to current/open; source msha-controller-operator-history