# Relationship history for MSHA mine 1510947

Current hierarchy: **Schweitzer Roy B → R B S Inc → No 3 Surface**

- 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:** Schweitzer Roy B → No 3 Surface; 1976-02-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** R B S Inc → No 3 Surface; 1977-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Schweitzer Roy B → R B S Inc; 1977-10-01 to current/open; source msha-controller-operator-history