# Relationship history for MSHA mine 3301505

Current hierarchy: **Kenneth T  Wanstrath → Harrison Sand & Gravel Company Inc → HARRISON SAND & GRAVEL OHIO PLANT**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Harrison Sand & Gravel Company Inc → HARRISON SAND & GRAVEL OHIO PLANT; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Kenneth T  Wanstrath et al → HARRISON SAND & GRAVEL OHIO PLANT; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kenneth T  Wanstrath et al → Harrison Sand & Gravel Company Inc; 1950-01-01 to current/open; source msha-controller-operator-history