# Relationship history for MSHA mine 4500560

Current hierarchy: **CRH PLC → Central Pre-Mix Concrete Co. → Park Road 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Acme Concrete Company → Park Road Plant; 1950-01-01 to 1988-07-14; source msha-controller-operator-history
- **controller_controls_mine:** Donald H  Herak → Park Road Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Donald H  Herak → Acme Concrete Company; 1950-01-01 to 1988-07-14; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Park Road Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Acme Concrete Company → Park Road Plant; 1988-07-15 to 1988-11-13; source msha-controller-operator-history
- **controller_controls_mine:** Koppers Company Inc → Park Road Plant; 1988-07-15 to 1988-11-13; source msha-controller-operator-history
- **controller_controls_operator:** Koppers Company Inc → Acme Concrete Company; 1988-07-15 to 1988-11-13; source msha-controller-operator-history
- **operator_operates_mine:** Acme Materials & Construction Company → Park Road Plant; 1988-11-14 to 2000-06-29; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → Park Road Plant; 1988-11-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Acme Materials & Construction Company; 1988-11-14 to 2000-06-29; source msha-controller-operator-history
- **operator_operates_mine:** Central Pre-Mix Concrete Co. → Park Road Plant; 2000-06-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Central Pre-Mix Concrete Co.; 2000-06-30 to current/open; source msha-controller-operator-history