# Relationship history for MSHA mine 2302216

Current hierarchy: **Mark A  Barton → Barton Sand & Gravel → BARTON SAND & GRAVEL**

- 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 Sand & Gravel → BARTON SAND & GRAVEL; 2000-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mark A  Barton → BARTON SAND & GRAVEL; 2000-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mark A  Barton → Barton Sand & Gravel; 2000-10-01 to current/open; source msha-controller-operator-history