# Relationship history for MSHA mine 4503128

Current hierarchy: **Stevens County-Wa → Stevens County Department Of Public Works → Portable Plant No 3**

- 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:** Stevens County Department Of Public Works → Portable Plant No 3; 1987-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Stevens County-Wa → Portable Plant No 3; 1987-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Stevens County-Wa → Stevens County Department Of Public Works; 1987-03-01 to current/open; source msha-controller-operator-history