# Relationship history for MSHA mine 4502630

Current hierarchy: **Samac George B → Samac Trucking → Grays River 7000 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** George  Weyerhaeuser et al → Grays River 7000 Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Weyerhaeuser Company → Grays River 7000 Pit; 1979-01-01 to 1979-11-30; source msha-controller-operator-history
- **controller_controls_operator:** George  Weyerhaeuser et al → Weyerhaeuser Company; 1979-01-01 to 1979-11-30; source msha-controller-operator-history
- **operator_operates_mine:** Samac Trucking → Grays River 7000 Pit; 1979-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Samac George B → Grays River 7000 Pit; 1979-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Samac George B → Samac Trucking; 1979-12-01 to current/open; source msha-controller-operator-history