# Relationship history for MSHA mine 3609621

Current hierarchy: **Harry J  Silvers → Harry Silvers Quarry → Ross Quarry**

- 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:** Harry J  Silvers → Ross Quarry; 2008-01-22 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Belcher & Sons → Ross Quarry; 2008-05-06 to 2009-02-25; source msha-controller-operator-history
- **controller_controls_mine:** Tony  Belcher → Ross Quarry; 2008-05-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tony  Belcher → Belcher & Sons; 2008-05-06 to 2009-02-25; source msha-controller-operator-history
- **operator_operates_mine:** Harry Silvers Quarry → Ross Quarry; 2009-02-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harry J  Silvers → Harry Silvers Quarry; 2009-02-26 to current/open; source msha-controller-operator-history