# Relationship history for MSHA mine 0404628

Current hierarchy: **Bollman Fred A → Lassen Sand & Gravel → Skedadele 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

- **controller_controls_mine:** Bollman Fred A → Skedadele Pit; 1982-12-09 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Lassen Sand & Gravel → Skedadele Pit; 1983-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bollman Fred A → Lassen Sand & Gravel; 1983-02-01 to current/open; source msha-controller-operator-history