# Relationship history for MSHA mine 3503802

Current hierarchy: **John R Calvin → John Calvin → Scorpion1**

- 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:** Robin Tandy → Scorpion1; 2013-08-02 to 2018-06-26; source msha-controller-operator-history
- **controller_controls_mine:** Robin D  Tandy → Scorpion1; 2013-08-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robin D  Tandy → Robin Tandy; 2013-08-02 to 2018-06-26; source msha-controller-operator-history
- **operator_operates_mine:** John Calvin → Scorpion1; 2018-06-27 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** John R Calvin → Scorpion1; 2018-06-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John R Calvin → John Calvin; 2018-06-27 to current/open; source msha-controller-operator-history