# Relationship history for MSHA mine 0504609

Current hierarchy: **Brent  Tamburelli → Tamrock Gravel Company → Shot Rock 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Tamrock Gravel Company → Shot Rock Pit; 1998-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Brent  Tamburelli → Shot Rock Pit; 1998-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brent  Tamburelli → Tamrock Gravel Company; 1998-02-01 to current/open; source msha-controller-operator-history