# Relationship history for MSHA mine 0405597

Current hierarchy: **Siskiyou County-Ca → County of Siskiyou Dept of Public Works → Portable Screen Plant**

- 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

- **controller_controls_mine:** Siskiyou County-Ca → Portable Screen Plant; 1999-06-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** County of Siskiyou Dept of Public Works → Portable Screen Plant; 2004-04-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Siskiyou County-Ca → County of Siskiyou Dept of Public Works; 2004-04-15 to current/open; source msha-controller-operator-history