# Relationship history for MSHA mine 2002789

Current hierarchy: **Laidlaw Sheryl → Goodland Trucking → Power 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

- **operator_operates_mine:** Goodland Trucking → Power Plant; 1987-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Laidlaw Sheryl → Power Plant; 1987-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Laidlaw Sheryl → Goodland Trucking; 1987-10-01 to current/open; source msha-controller-operator-history