# Relationship history for MSHA mine 2602091

Current hierarchy: **Don  Andress → American Asphalt Inc → Powerscreen 706**

- 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

- **operator_operates_mine:** American Asphalt Inc → Powerscreen 706; 1988-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Don  Andress et al → Powerscreen 706; 1988-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Don  Andress et al → American Asphalt Inc; 1988-12-01 to current/open; source msha-controller-operator-history