# Relationship history for MSHA mine 3401708

Current hierarchy: **Mc Neill Douglas M → Mc Neill Construction Inc → Portable #1**

- 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:** Mc Neill Douglas M → Portable #1; 1989-11-16 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Mc Neill Construction Inc → Portable #1; 1990-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mc Neill Douglas M → Mc Neill Construction Inc; 1990-02-01 to current/open; source msha-controller-operator-history