# Relationship history for MSHA mine 1506916

Current hierarchy: **Haddix Blackburn Jr → Middle Fork Mining Company → No 1 Strip & Auger**

- 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:** Middle Fork Mining Company → No 1 Strip & Auger; 1974-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Haddix Blackburn Jr → No 1 Strip & Auger; 1974-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Haddix Blackburn Jr → Middle Fork Mining Company; 1974-02-01 to current/open; source msha-controller-operator-history