# Relationship history for MSHA mine 2902058

Current hierarchy: **Smith Warren → Warren Smith Contracting 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Smith Warren → Portable Crusher; 1985-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Warren Smith Contracting Inc → Portable Crusher; 1990-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Smith Warren → Warren Smith Contracting Inc; 1990-08-01 to current/open; source msha-controller-operator-history