# Relationship history for MSHA mine 3700168

Current hierarchy: **Sydney H Robinson Excavating Compan → Sydney H Robinson Excavating Compan → Hopkins Hill Road 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Sydney H Robinson Excavating Compan → Hopkins Hill Road Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Sydney H Robinson Excavating Compan → Hopkins Hill Road Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Sydney H Robinson Excavating Compan → Sydney H Robinson Excavating Compan; 1950-01-01 to current/open; source msha-controller-operator-history