# Relationship history for MSHA mine 4703164

Current hierarchy: **Barbara R  Boulanger → Boulanger Construction Company, Inc. → Eagle Double Screw**

- 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

- **controller_controls_mine:** Barbara R  Boulanger → Eagle Double Screw; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Boulanger Construction Company Inc → Eagle Double Screw; 1998-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Barbara R  Boulanger → Boulanger Construction Company Inc; 1998-10-01 to current/open; source msha-controller-operator-history