# Relationship history for MSHA mine 4405739

Current hierarchy: **Heckford John → Blue Flame Coal Company Inc → Strip Mine No 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Blue Flame Coal Company Inc → Strip Mine No 1; 1981-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Heckford John → Strip Mine No 1; 1981-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Heckford John → Blue Flame Coal Company Inc; 1981-09-01 to current/open; source msha-controller-operator-history