# Relationship history for MSHA mine 0600643

Current hierarchy: **John  McKnight → Mc Knight Sand & Gravel Inc → ELLINGTON PLANT**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Mc Knight Sand & Gravel Inc → ELLINGTON PLANT; 1995-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** John  McKnight → ELLINGTON PLANT; 1995-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John  McKnight → Mc Knight Sand & Gravel Inc; 1995-04-01 to current/open; source msha-controller-operator-history