# Relationship history for MSHA mine 2401987

Current hierarchy: **Judith Basin County-MT → Judith Basin County Road Dept → Judith Basin Co 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Judith Basin County-MT → Judith Basin Co Portable Crusher; 1981-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Judith Basin County Road Dept → Judith Basin Co Portable Crusher; 1992-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Judith Basin County-MT → Judith Basin County Road Dept; 1992-09-01 to current/open; source msha-controller-operator-history