# Relationship history for MSHA mine 0102243

Current hierarchy: **Webb Tina K → Key Coal Company → Key Coal Company**

- 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:** C & S Coal Company Inc → Key Coal Company; 1980-10-01 to 1981-01-01; source msha-controller-operator-history
- **controller_controls_mine:** Cagle Melvin → Key Coal Company; 1980-10-01 to 1981-01-01; source msha-controller-operator-history
- **controller_controls_operator:** Cagle Melvin → C & S Coal Company Inc; 1980-10-01 to 1981-01-01; source msha-controller-operator-history
- **operator_operates_mine:** May Coal Company Inc → Key Coal Company; 1981-01-02 to 1985-01-10; source msha-controller-operator-history
- **controller_controls_mine:** May E Owen → Key Coal Company; 1981-01-02 to 1985-01-10; source msha-controller-operator-history
- **controller_controls_operator:** May E Owen → May Coal Company Inc; 1981-01-02 to 1985-01-10; source msha-controller-operator-history
- **operator_operates_mine:** Key Coal Company Inc → Key Coal Company; 1985-01-11 to 1985-11-01; source msha-controller-operator-history
- **controller_controls_mine:** Key David → Key Coal Company; 1985-01-11 to 1985-11-01; source msha-controller-operator-history
- **controller_controls_operator:** Key David → Key Coal Company Inc; 1985-01-11 to 1985-11-01; source msha-controller-operator-history
- **operator_operates_mine:** Key Coal Company → Key Coal Company; 1985-11-02 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Webb Tina K → Key Coal Company; 1985-11-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Webb Tina K → Key Coal Company; 1985-11-02 to current/open; source msha-controller-operator-history