# Relationship history for MSHA mine 3302403

Current hierarchy: **Minor E  Kirby → Kirby & Sons Inc → KIRBYS 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:** Kirby & Sons Inc → KIRBYS SAND & GRAVEL; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Minor E  Kirby et al → KIRBYS SAND & GRAVEL; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Minor E  Kirby et al → Kirby & Sons Inc; 1950-01-01 to current/open; source msha-controller-operator-history