# Relationship history for MSHA mine 4202497

Current hierarchy: **Russell K  Barton → BARTON ROCK → WILLOW CREEK CANYON PIT**

- 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:** Barton Rock → WILLOW CREEK CANYON PIT; 2008-04-09 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Russell K  Barton → WILLOW CREEK CANYON PIT; 2008-04-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Russell K  Barton → Barton Rock; 2008-04-09 to current/open; source msha-controller-operator-history