# Relationship history for MSHA mine 0401763

Current hierarchy: **Colas S A → UNITED ROCK PRODUCTS CORP → IRWINDALE PLANT**

- 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:** Blue Diamond Materials → IRWINDALE PLANT; 1950-01-01 to 1988-12-29; source msha-controller-operator-history
- **controller_controls_mine:** Koppers Company Inc → IRWINDALE PLANT; 1950-01-01 to 1988-12-29; source msha-controller-operator-history
- **controller_controls_operator:** Koppers Company Inc → Blue Diamond Materials; 1950-01-01 to 1988-12-29; source msha-controller-operator-history
- **operator_operates_mine:** United Rock Products Corp → IRWINDALE PLANT; 1988-12-30 to 1999-08-31; source msha-controller-operator-history
- **controller_controls_mine:** URM Inc → IRWINDALE PLANT; 1988-12-30 to 1999-08-31; source msha-controller-operator-history
- **controller_controls_operator:** URM Inc → United Rock Products Corp; 1988-12-30 to 1999-08-31; source msha-controller-operator-history
- **operator_operates_mine:** United Rock Products Corp → IRWINDALE PLANT; 1999-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Colas S A → IRWINDALE PLANT; 1999-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Colas S A → United Rock Products Corp; 1999-09-01 to current/open; source msha-controller-operator-history