# Relationship history for MSHA mine 4101915

Current hierarchy: **H Dean  Phipps → Phipps Sand & Gravel Company Inc → PHIPPS SAND & GRAVEL CO**

- 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:** Phipps Sand & Gravel Company Inc → PHIPPS SAND & GRAVEL CO; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** H Dean  Phipps → PHIPPS SAND & GRAVEL CO; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** H Dean  Phipps → Phipps Sand & Gravel Company Inc; 1950-01-01 to current/open; source msha-controller-operator-history