# Relationship history for MSHA mine 3500209

Current hierarchy: **Tuss Tom → Tuss Crushing Company → Hood River Sand & Gravel Pit**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Hood River Sand & Gravel → Hood River Sand & Gravel Pit; 1950-01-01 to 1979-04-23; source msha-controller-operator-history
- **controller_controls_mine:** Howard  Houston → Hood River Sand & Gravel Pit; 1950-01-01 to 2019-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Howard  Houston → Hood River Sand & Gravel; 1950-01-01 to 1979-04-23; source msha-controller-operator-history
- **controller_controls_mine:** Schwartz Dave & Roger Olson → Hood River Sand & Gravel Pit; 1978-03-09 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Chelatchie Rock Products → Hood River Sand & Gravel Pit; 1979-04-24 to 1981-09-09; source msha-controller-operator-history
- **controller_controls_operator:** Schwartz Dave & Roger Olson → Chelatchie Rock Products; 1979-04-24 to 1981-09-09; source msha-controller-operator-history
- **controller_controls_mine:** Tuss Tom → Hood River Sand & Gravel Pit; 1979-05-30 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Tuss Crushing Company → Hood River Sand & Gravel Pit; 1981-09-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tuss Tom → Tuss Crushing Company; 1981-09-10 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Hood River Sand & Gravel Pit; 2019-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Hood River Sand & Gravel; 2019-04-01 to 1979-04-23; source msha-controller-operator-history