# Relationship history for MSHA mine 3503311

Current hierarchy: **CRH PLC → Hood River Sand & Gravel Redi Mix, Inc. → Portable Screening Plant**

- 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:** Howard  Houston → Portable Screening Plant; 1950-01-01 to 2019-03-31; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Portable Screening Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Hood River Sand & Gravel Redi Mix, Inc. → Portable Screening Plant; 1988-06-01 to 2024-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Howard  Houston → Hood River Sand & Gravel Redi Mix, Inc.; 1988-06-01 to 2019-03-31; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Portable Screening Plant; 2019-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Hood River Sand & Gravel Redi Mix, Inc.; 2019-04-01 to 2024-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Hood River Sand & Gravel Redi Mix, Inc. → Portable Screening Plant; 2024-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Hood River Sand & Gravel Redi Mix, Inc.; 2024-04-01 to current/open; source msha-controller-operator-history