# Relationship history for MSHA mine 3606227

Current hierarchy: **Bertelle Bruno → Bertelle & Sons Coal → Vosco 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Schafer George → Vosco Strip; 1976-05-13 to 1979-06-03; source msha-controller-operator-history
- **operator_operates_mine:** Vosco Inc → Vosco Strip; 1976-09-27 to 1979-05-08; source msha-controller-operator-history
- **controller_controls_operator:** Schafer George → Vosco Inc; 1976-09-27 to 1979-05-08; source msha-controller-operator-history
- **controller_controls_mine:** Bertelle Bruno → Vosco Strip; 1977-02-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Bertelle & Sons Coal → Vosco Strip; 1979-05-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bertelle Bruno → Bertelle & Sons Coal; 1979-05-09 to current/open; source msha-controller-operator-history