# Relationship history for MSHA mine 3503621

Current hierarchy: **David Alan  Hornsby → Nesko Rock → Nesko Rock-Portable Plant #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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** David Alan  Hornsby → Nesko Rock-Portable Plant #2; 2004-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Nesko Rock → Nesko Rock-Portable Plant #2; 2005-07-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David Alan  Hornsby → Nesko Rock; 2005-07-15 to current/open; source msha-controller-operator-history