# Relationship history for MSHA mine 2602394

Current hierarchy: **CRH PLC → Western Rock Products → Portable Wash Plant #1**

- 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

- **controller_controls_mine:** U S Aggregate Inc → Portable Wash Plant #1; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Western Rock Products Inc → Portable Wash Plant #1; 1999-09-01 to 2002-05-28; source msha-controller-operator-history
- **controller_controls_operator:** U S Aggregate Inc → Western Rock Products Inc; 1999-09-01 to 2002-05-28; source msha-controller-operator-history
- **operator_operates_mine:** Western Rock Products → Portable Wash Plant #1; 2002-05-29 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Portable Wash Plant #1; 2002-05-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Western Rock Products; 2002-05-29 to current/open; source msha-controller-operator-history