# Relationship history for MSHA mine 1102750

Current hierarchy: **CRH PLC → Cessford Construction Company → Dallas City 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Heidi Cessford  Krabbe et al → Dallas City Quarry; 1950-01-01 to 2007-08-23; source msha-controller-operator-history
- **operator_operates_mine:** Cessford Construction Company → Dallas City Quarry; 1980-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Heidi Cessford  Krabbe et al → Cessford Construction Company; 1980-08-01 to 2007-08-23; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Dallas City Quarry; 2007-08-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Cessford Construction Company; 2007-08-24 to current/open; source msha-controller-operator-history