# Relationship history for MSHA mine 3200153

Current hierarchy: **Donald  Dusek; Ken  Dusek → Dusek Sand & Gravel Inc → PORTABLE SCREENER**

- 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

- **controller_controls_mine:** Ken  Dusek  et al → PORTABLE SCREENER; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Ellingson Gravel Company → PORTABLE SCREENER; 1950-01-01 to 1985-07-15; source msha-controller-operator-history
- **controller_controls_mine:** Ellingson Carol → PORTABLE SCREENER; 1950-01-01 to 1985-07-15; source msha-controller-operator-history
- **controller_controls_operator:** Ellingson Carol → Ellingson Gravel Company; 1950-01-01 to 1985-07-15; source msha-controller-operator-history
- **operator_operates_mine:** Dusek Sand & Gravel Inc → PORTABLE SCREENER; 1985-07-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ken  Dusek  et al → Dusek Sand & Gravel Inc; 1985-07-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Donald  Dusek  et al → Dusek Sand & Gravel Inc; 1985-07-16 to current/open; source msha-controller-operator-history