# Relationship history for MSHA mine 3303430

Current hierarchy: **Rybski Vernon A → Mid-Ohio Mining Company → Menzie No 1 Strip**

- 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:** Rybski Vernon A → Menzie No 1 Strip; 1975-04-22 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Mid-Ohio Mining Company → Menzie No 1 Strip; 1976-02-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Rybski Vernon A → Mid-Ohio Mining Company; 1976-02-23 to current/open; source msha-controller-operator-history