# Relationship history for MSHA mine 4503088

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

## Valid-time edges

- **controller_controls_mine:** Samac George B → Samac Portable Plant; 1979-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Samac Trucking → Samac Portable Plant; 1986-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Samac George B → Samac Trucking; 1986-06-01 to current/open; source msha-controller-operator-history