# Relationship history for MSHA mine 4503384

Current hierarchy: **CRH PLC → Interstate Concrete and Asphalt Company → Airway Sand & Gravel**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **controller_controls_mine:** Eucon Corporation → Airway Sand & Gravel; 1983-01-11 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Airway Sand & Gravel; 1987-09-18 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Spokane Rock Products Inc → Airway Sand & Gravel; 1999-01-01 to 2018-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Eucon Corporation → Spokane Rock Products Inc; 1999-01-01 to 2018-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Interstate Concrete and Asphalt Company → Airway Sand & Gravel; 2018-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Interstate Concrete and Asphalt Company; 2018-04-01 to current/open; source msha-controller-operator-history