# Relationship history for MSHA mine 3002506

Current hierarchy: **Yvonne M  Pratt → Ritchie Bros Slate Company Inc → PHILLIPS QUARRY**

- 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

- **controller_controls_mine:** Yvonne M  Pratt et al → PHILLIPS QUARRY; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Ritchie Bros Slate Company Inc → PHILLIPS QUARRY; 1980-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Yvonne M  Pratt et al → Ritchie Bros Slate Company Inc; 1980-04-01 to current/open; source msha-controller-operator-history