# Relationship history for MSHA mine 3101575

Current hierarchy: **CRH PLC → Harrison Construction Company → Murphy Quarry**

- 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:** Harrison Construction Company → Murphy Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ashland Inc → Murphy Quarry; 1950-01-01 to 2006-08-27; source msha-controller-operator-history
- **controller_controls_operator:** Ashland Inc → Harrison Construction Company; 1950-01-01 to 2006-08-27; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Murphy Quarry; 2006-08-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Harrison Construction Company; 2006-08-28 to current/open; source msha-controller-operator-history