# Relationship history for MSHA mine 2602039

Current hierarchy: **Cornella Delbert L → Western Central Concrete Inc → S P 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:** Western Central Concrete Inc → S P Gravel Pit; 1987-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Cornella Delbert L → S P Gravel Pit; 1987-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cornella Delbert L → Western Central Concrete Inc; 1987-08-01 to current/open; source msha-controller-operator-history