# Relationship history for MSHA mine 2200546

Current hierarchy: **CRH PLC → Blain Sand & Gravel Inc → CEDAR GROVE**

- 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

- **controller_controls_mine:** Blain Sand & Gravel Inc → CEDAR GROVE; 1950-01-01 to 2021-12-02; source msha-controller-operator-history
- **controller_controls_mine:** Polk Dale & Son Inc → CEDAR GROVE; 1979-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Dale Polk & Son Inc → CEDAR GROVE; 1982-07-01 to 1990-02-28; source msha-controller-operator-history
- **controller_controls_operator:** Polk Dale & Son Inc → Dale Polk & Son Inc; 1982-07-01 to 1990-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Blain Sand & Gravel Inc → CEDAR GROVE; 1990-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Blain Sand & Gravel Inc → Blain Sand & Gravel Inc; 1990-03-01 to 2021-12-02; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → CEDAR GROVE; 2021-12-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Blain Sand & Gravel Inc; 2021-12-03 to current/open; source msha-controller-operator-history