# Relationship history for MSHA mine 1514217

Current hierarchy: **Williamson Tom & Tommy R → T & T Coal Company → Surface No 1**

- 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:** T & T Coal Company → Surface No 1; 1983-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Williamson Tom & Tommy R → Surface No 1; 1983-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Williamson Tom & Tommy R → T & T Coal Company; 1983-09-01 to current/open; source msha-controller-operator-history