# Relationship history for MSHA mine 1511977

Current hierarchy: **Blevins Jan → Misty Coal Company → No 4 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:** Rossco Mining Company Inc → No 4 Mine; 1979-07-01 to 1980-12-18; source msha-controller-operator-history
- **controller_controls_mine:** Smith D L → No 4 Mine; 1979-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Smith D L → Rossco Mining Company Inc; 1979-07-01 to 1980-12-18; source msha-controller-operator-history
- **controller_controls_mine:** Blevins Jan → No 4 Mine; 1980-05-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Misty Coal Company → No 4 Mine; 1980-12-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Blevins Jan → Misty Coal Company; 1980-12-19 to current/open; source msha-controller-operator-history