# Relationship history for MSHA mine 2402618

Current hierarchy: **Mark A  Herzog → Skyline Dredging & Excavating → Skyline D and E #2  Portable Crusher**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Mark A  Herzog → Skyline D and E #2  Portable Crusher; 2011-08-16 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Skyline Dredging & Excavating → Skyline D and E #2  Portable Crusher; 2012-04-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mark A  Herzog → Skyline Dredging & Excavating; 2012-04-15 to current/open; source msha-controller-operator-history