# Relationship history for MSHA mine 1509312

Current hierarchy: **Tackett Hershell → Dry Branch Coal Company Inc → I 121**

- 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:** Tackett Walker → I 121; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Ligon Preparation Company → I 121; 1975-10-28 to 1979-01-31; source msha-controller-operator-history
- **controller_controls_operator:** Tackett Walker → Ligon Preparation Company; 1975-10-28 to 1979-01-31; source msha-controller-operator-history
- **operator_operates_mine:** Ligon Preparation Company → I 121; 1979-02-01 to 1984-11-04; source msha-controller-operator-history
- **controller_controls_mine:** Tackett Paul D → I 121; 1979-02-01 to 1984-11-04; source msha-controller-operator-history
- **controller_controls_operator:** Tackett Paul D → Ligon Preparation Company; 1979-02-01 to 1984-11-04; source msha-controller-operator-history
- **operator_operates_mine:** Dry Branch Coal Company Inc → I 121; 1984-11-05 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Tackett Hershell → I 121; 1984-11-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tackett Hershell → Dry Branch Coal Company Inc; 1984-11-05 to current/open; source msha-controller-operator-history