# Relationship history for MSHA mine 4606515

Current hierarchy: **Hart Reuben F → Hart Coal Company Inc → Mine No 4**

- 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

- **controller_controls_mine:** Hart Reuben F → Mine No 4; 1980-05-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Hart Coal Company Inc → Mine No 4; 1982-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hart Reuben F → Hart Coal Company Inc; 1982-04-01 to current/open; source msha-controller-operator-history