# Relationship history for MSHA mine 5100221

Current hierarchy: **Roy  Sonomura → M Sonomura Contracting Company Inc → Cedar Rapids**

- 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

- **controller_controls_mine:** Roy  Sonomura → Cedar Rapids; 1987-09-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** M Sonomura Contracting Company Inc → Cedar Rapids; 1996-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Roy  Sonomura → M Sonomura Contracting Company Inc; 1996-02-01 to current/open; source msha-controller-operator-history