# Relationship history for MSHA mine 4202054

Current hierarchy: **Wallis Brad → B Wallis Industries → B W I Portable #1**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** B Wallis Industries → B W I Portable #1; 1990-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Wallis Brad → B W I Portable #1; 1990-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Wallis Brad → B Wallis Industries; 1990-01-01 to current/open; source msha-controller-operator-history