# Relationship history for MSHA mine 2602192

Current hierarchy: **American Asphalt & Grading Co → American Asphalt & Grading Company → Equipment 711**

- 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 & Grading Company → Equipment 711; 1991-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Don  Andress et al → Equipment 711; 1994-04-01 to 2004-06-15; source msha-controller-operator-history
- **controller_controls_operator:** Don  Andress et al → American Asphalt & Grading Company; 1994-04-01 to 2004-06-15; source msha-controller-operator-history
- **controller_controls_mine:** American Asphalt & Grading Co → Equipment 711; 2004-06-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** American Asphalt & Grading Co → American Asphalt & Grading Company; 2004-06-16 to current/open; source msha-controller-operator-history