# Relationship history for MSHA mine 2401869

Current hierarchy: **Zook Donald & Glen → Modern Exploration Development & Mining → Passage Placer**

- 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:** Zook Donald & Glen → Passage Placer; 1982-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Modern Exploration Development & Mining → Passage Placer; 1988-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Zook Donald & Glen → Modern Exploration Development & Mining; 1988-06-01 to current/open; source msha-controller-operator-history