# Relationship history for MSHA mine 2003603

Current hierarchy: **Patrick  Ziemnick → Ziemnick Excavating, Inc. → Screen Plant #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

- **operator_operates_mine:** Ziemnick Excavating, Inc. → Screen Plant #1; 2020-06-30 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Patrick  Ziemnick → Screen Plant #1; 2020-06-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Patrick  Ziemnick → Ziemnick Excavating, Inc.; 2020-06-30 to current/open; source msha-controller-operator-history