# Relationship history for MSHA mine 1701187

Current hierarchy: **Town of Dexter, ME → Town of Dexter Public Works → Portable 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Town of Dexter Public Works → Portable Screen; 2026-05-04 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Town of Dexter, ME → Portable Screen; 2026-05-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Town of Dexter, ME → Town of Dexter Public Works; 2026-05-04 to current/open; source msha-controller-operator-history