# Relationship history for MSHA mine 4000768

Current hierarchy: **Owens Curtis → Oliver Springs Mining Co Inc → No 6 Block Mine**

- 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:** Oliver Springs Mining Co Inc → No 6 Block Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Owens Curtis → No 6 Block Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Owens Curtis → Oliver Springs Mining Co Inc; 1950-01-01 to current/open; source msha-controller-operator-history