# Relationship history for MSHA mine 4500628

Current hierarchy: **James  Wallace → Forks Sand & Gravel → Campbell Hole 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:** Forks Sand & Gravel → Campbell Hole Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** James  Wallace → Campbell Hole Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James  Wallace → Forks Sand & Gravel; 1950-01-01 to current/open; source msha-controller-operator-history