# Relationship history for MSHA mine 3606253

Current hierarchy: **Thomas L  Hill → T L Hill Coal Company → Hill Strip**

- 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 L Hill Coal Company → Hill Strip; 1976-11-03 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Thomas L  Hill → Hill Strip; 1976-11-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thomas L  Hill → T L Hill Coal Company; 1976-11-03 to current/open; source msha-controller-operator-history