# Relationship history for MSHA mine 3301607

Current hierarchy: **Crano James V → Portage Lakes Sand & Gravel Company → Portage Lakes Sand & Gravel Company**

- 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:** Portage Lakes Sand & Gravel Company → Portage Lakes Sand & Gravel Company; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Crano James V → Portage Lakes Sand & Gravel Company; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Crano James V → Portage Lakes Sand & Gravel Company; 1950-01-01 to current/open; source msha-controller-operator-history