# Relationship history for MSHA mine 4300269

Current hierarchy: **Mary  Hart; Stephen M  Hart → Hart Construction Company Inc → Pownal Gravel Pit**

- 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

- **operator_operates_mine:** Hart Construction Company Inc → Pownal Gravel Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Stephen M  Hart et al → Pownal Gravel Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Stephen M  Hart et al → Hart Construction Company Inc; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mary  Hart et al → Hart Construction Company Inc; 1950-01-01 to current/open; source msha-controller-operator-history