# Relationship history for MSHA mine 2900825

Current hierarchy: **Cosper Donald H → American Crushing Inc → Portable Crusher**

- 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

- **operator_operates_mine:** American Crushing Inc → Portable Crusher; 1987-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Cosper Donald H → Portable Crusher; 1987-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cosper Donald H → American Crushing Inc; 1987-10-01 to current/open; source msha-controller-operator-history