# Relationship history for MSHA mine 2003329

Current hierarchy: **Michael R  Hyrkas → Hyrkas Gravel → Extec 5000 Screen Plant**

- 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:** Hyrkas Gravel → Extec 5000 Screen Plant; 2005-07-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Michael R  Hyrkas → Extec 5000 Screen Plant; 2005-07-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Michael R  Hyrkas → Hyrkas Gravel; 2005-07-25 to current/open; source msha-controller-operator-history