# Relationship history for MSHA mine 1900773

Current hierarchy: **Town Of Bridgewater-Ma → Town Of Bridgewater → Bridgewater Highway Dept Pit And Pl**

- 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:** Town Of Bridgewater → Bridgewater Highway Dept Pit And Pl; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Town Of Bridgewater-Ma → Bridgewater Highway Dept Pit And Pl; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Town Of Bridgewater-Ma → Town Of Bridgewater; 1950-01-01 to current/open; source msha-controller-operator-history