# Relationship history for MSHA mine 1401823

Current hierarchy: **CRH PLC → Holliday Sand & Gravel Company, Inc → HSS Q Portable Plant 4**

- 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:** Ash Grove Cement Company → HSS Q Portable Plant 4; 2008-08-01 to 2018-06-20; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → HSS Q Portable Plant 4; 2018-06-21 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Holliday Sand & Gravel Company, Inc → HSS Q Portable Plant 4; 2021-03-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ash Grove Cement Company → Holliday Sand & Gravel Company, Inc; 2021-03-19 to 2018-06-20; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Holliday Sand & Gravel Company, Inc; 2021-03-19 to current/open; source msha-controller-operator-history