# Relationship history for MSHA mine 2602016

Current hierarchy: **Cornella Delbert L → Western Central Concrete Inc → Wcc Pit And Crusher**

- 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:** Curtis Machinery Inc → Wcc Pit And Crusher; 1987-06-01 to 1988-02-08; source msha-controller-operator-history
- **controller_controls_mine:** Curtis Walter Jr → Wcc Pit And Crusher; 1987-06-01 to 1988-02-08; source msha-controller-operator-history
- **controller_controls_operator:** Curtis Walter Jr → Curtis Machinery Inc; 1987-06-01 to 1988-02-08; source msha-controller-operator-history
- **controller_controls_mine:** Cornella Delbert L → Wcc Pit And Crusher; 1987-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Western Central Concrete Inc → Wcc Pit And Crusher; 1988-02-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cornella Delbert L → Western Central Concrete Inc; 1988-02-09 to current/open; source msha-controller-operator-history