# Relationship history for MSHA mine 3609537

Current hierarchy: **Scott R  Birchard → Birchard Flagstone → Birchard Portable**

- 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:** Birchard Flagstone → Birchard Portable; 2007-06-21 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Scott R  Birchard → Birchard Portable; 2007-06-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Scott R  Birchard → Birchard Flagstone; 2007-06-21 to current/open; source msha-controller-operator-history