# Relationship history for MSHA mine 1506809

Current hierarchy: **TECO Energy Inc → Gatliff Coal Company Inc → Gatliff Tipple #3**

- 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:** TECO Energy Inc → Gatliff Tipple #3; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Kaneb Services Inc → Gatliff Tipple #3; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Appalachian Contracting Company → Gatliff Tipple #3; 1973-10-04 to 1976-08-22; source msha-controller-operator-history
- **controller_controls_operator:** Kaneb Services Inc → Appalachian Contracting Company; 1973-10-04 to 1976-08-22; source msha-controller-operator-history
- **operator_operates_mine:** Boyle Air Coal Company Inc → Gatliff Tipple #3; 1976-08-23 to 1988-09-08; source msha-controller-operator-history
- **controller_controls_mine:** Smith Elvin & A E → Gatliff Tipple #3; 1976-08-23 to 1988-09-08; source msha-controller-operator-history
- **controller_controls_operator:** Smith Elvin & A E → Boyle Air Coal Company Inc; 1976-08-23 to 1988-09-08; source msha-controller-operator-history
- **operator_operates_mine:** Gatliff Coal Company Inc → Gatliff Tipple #3; 1988-09-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** TECO Energy Inc → Gatliff Coal Company Inc; 1988-09-09 to current/open; source msha-controller-operator-history