# Relationship history for MSHA mine 0505175

Current hierarchy: **Darwin Grant  Smith → Smith's Materials LLC → New Wash 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:** Smith's Materials LLC → New Wash Plant; 2023-05-10 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Darwin Grant  Smith → New Wash Plant; 2023-05-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Darwin Grant  Smith → Smith's Materials LLC; 2023-05-10 to current/open; source msha-controller-operator-history