# Relationship history for MSHA mine 3607404

Current hierarchy: **Schomaker Richard C → West Penn Tipple Company Inc → Woodlawn Tcc**

- 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

- **controller_controls_mine:** Schomaker Richard C → Woodlawn Tcc; 1977-10-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** West Penn Tipple Company Inc → Woodlawn Tcc; 1982-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Schomaker Richard C → West Penn Tipple Company Inc; 1982-12-01 to current/open; source msha-controller-operator-history