# Relationship history for MSHA mine 0404456

Current hierarchy: **Harkness Verne W → Vail Mining & Milling Company → O K West #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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Vail Mining & Milling Company → O K West #1; 1980-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Harkness Verne W Et Al → O K West #1; 1980-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harkness Verne W Et Al → Vail Mining & Milling Company; 1980-09-01 to current/open; source msha-controller-operator-history