# Relationship history for MSHA mine 4202581

Current hierarchy: **John D  Wickman → Sinbad Construction Company → Portable #1**

- 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:** Sinbad Construction Company Inc, → Portable #1; 2012-02-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** John D  Wickman → Portable #1; 2012-02-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John D  Wickman → Sinbad Construction Company Inc,; 2012-02-14 to current/open; source msha-controller-operator-history