# Relationship history for MSHA mine 4500631

Current hierarchy: **CRH PLC → Central Pre-Mix Concrete Co → Toppenish Facility**

- 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:** Graham & Morris Construction Co Inc → Toppenish Facility; 1950-01-01 to 2002-12-31; source msha-controller-operator-history
- **controller_controls_mine:** William  Douglas  et al → Toppenish Facility; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William  Douglas  et al → Graham & Morris Construction Co Inc; 1950-01-01 to 2002-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Martin  Drollinger  et al → Graham & Morris Construction Co Inc; 1950-01-01 to 2002-12-31; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Toppenish Facility; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Central Pre-Mix Concrete Co → Toppenish Facility; 2003-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Central Pre-Mix Concrete Co; 2003-01-01 to current/open; source msha-controller-operator-history