# Relationship history for MSHA mine 1700788

Current hierarchy: **Keith Patrick  Durgin → Bear River Excavation → Davis Pit**

- 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:** Bear River Excavation → Davis Pit; 2005-10-28 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Keith Patrick  Durgin → Davis Pit; 2005-10-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Keith Patrick  Durgin → Bear River Excavation; 2005-10-28 to current/open; source msha-controller-operator-history