# Relationship history for MSHA mine 4201632

Current hierarchy: **Engstrom Clarence & Robert → Engstrom Construction Company → Engstrom Crusher #2**

- 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:** Engstrom Clarence & Robert → Engstrom Crusher #2; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Engstrom Construction Company → Engstrom Crusher #2; 1979-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Engstrom Clarence & Robert → Engstrom Construction Company; 1979-11-01 to current/open; source msha-controller-operator-history