# Relationship history for MSHA mine 3304304

Current hierarchy: **Ray  Perrino → Willowbrook Sand & Gravel LLC → Willowbrook Sand & Gravel LLC**

- 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:** Willowbrook Sand & Gravel LLC → Willowbrook Sand & Gravel LLC; 1993-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ray  Perrino → Willowbrook Sand & Gravel LLC; 1993-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ray  Perrino → Willowbrook Sand & Gravel LLC; 1993-08-01 to current/open; source msha-controller-operator-history