# Relationship history for MSHA mine 1800611

Current hierarchy: **Jefferys Stanley → Jefco Inc → Delta #2 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:** Delta Industries Inc → Delta #2 Strip; 1972-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Delta Mining Inc → Delta #2 Strip; 1976-01-01 to 1993-03-02; source msha-controller-operator-history
- **controller_controls_operator:** Delta Industries Inc → Delta Mining Inc; 1976-01-01 to 1993-03-02; source msha-controller-operator-history
- **operator_operates_mine:** Jefco Inc → Delta #2 Strip; 1993-03-03 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Jefferys Stanley → Delta #2 Strip; 1993-03-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jefferys Stanley → Jefco Inc; 1993-03-03 to current/open; source msha-controller-operator-history