# Relationship history for MSHA mine 4503242

Current hierarchy: **CRH PLC → Interstate Concrete & Asphalt Company → Dawson Sand & Gravel**

- 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:** CRH PLC → Dawson Sand & Gravel; 1987-09-18 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Dawson Trucking Inc → Dawson Sand & Gravel; 1991-07-01 to 2026-01-20; source msha-controller-operator-history
- **controller_controls_mine:** Dennis L  Dawson → Dawson Sand & Gravel; 1991-07-01 to 2013-04-10; source msha-controller-operator-history
- **controller_controls_operator:** Dennis L  Dawson → Dawson Trucking Inc; 1991-07-01 to 2013-04-10; source msha-controller-operator-history
- **controller_controls_mine:** Duane A  Dawson et al → Dawson Sand & Gravel; 2013-04-11 to 2024-12-26; source msha-controller-operator-history
- **controller_controls_operator:** Duane A  Dawson et al → Dawson Trucking Inc; 2013-04-11 to 2024-12-26; source msha-controller-operator-history
- **controller_controls_operator:** Douglas E  Dawson et al → Dawson Trucking Inc; 2013-04-11 to 2024-12-26; source msha-controller-operator-history
- **controller_controls_mine:** Douglas Eugene  Dawson → Dawson Sand & Gravel; 2024-12-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Douglas Eugene  Dawson → Dawson Trucking Inc; 2024-12-27 to 2026-01-20; source msha-controller-operator-history
- **operator_operates_mine:** Interstate Concrete & Asphalt Company → Dawson Sand & Gravel; 2026-01-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Interstate Concrete & Asphalt Company; 2026-01-21 to current/open; source msha-controller-operator-history