# Relationship history for MSHA mine 3002688

Current hierarchy: **Essex County-Ny → Essex County Department Of Public Works → COUNTY SCREEN PORTABLE MUNICIPAL SCREEN**

- 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:** Essex County-Ny → COUNTY SCREEN PORTABLE MUNICIPAL SCREEN; 1979-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Essex County Department Of Public Works → COUNTY SCREEN PORTABLE MUNICIPAL SCREEN; 1985-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Essex County-Ny → Essex County Department Of Public Works; 1985-05-01 to current/open; source msha-controller-operator-history