# Relationship history for MSHA mine 4702535

Current hierarchy: **Paul T  Ayres → American Materials Corp → Cedar Rapids Plant #757**

- 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:** Schuette Construction Company → Cedar Rapids Plant #757; 1950-01-01 to 1990-05-01; source msha-controller-operator-history
- **controller_controls_mine:** Schuette Ward → Cedar Rapids Plant #757; 1950-01-01 to 1990-05-01; source msha-controller-operator-history
- **controller_controls_operator:** Schuette Ward → Schuette Construction Company; 1950-01-01 to 1990-05-01; source msha-controller-operator-history
- **controller_controls_mine:** Paul T  Ayres → Cedar Rapids Plant #757; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** American Materials Corp → Cedar Rapids Plant #757; 1990-05-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Paul T  Ayres → American Materials Corp; 1990-05-02 to current/open; source msha-controller-operator-history