# Relationship history for MSHA mine 3901472

Current hierarchy: **Art E  Argo → Argo & Sons → Portable Crusher & Screener**

- 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:** Art Argo & Son's Inc → Portable Crusher & Screener; 2002-05-11 to 2009-06-11; source msha-controller-operator-history
- **controller_controls_mine:** Art  Argo Sr → Portable Crusher & Screener; 2002-05-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Art  Argo Sr → Art Argo & Son's Inc; 2002-05-11 to 2009-06-11; source msha-controller-operator-history
- **operator_operates_mine:** Argo & Sons → Portable Crusher & Screener; 2009-06-12 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Art E  Argo → Portable Crusher & Screener; 2009-06-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Art E  Argo → Argo & Sons; 2009-06-12 to current/open; source msha-controller-operator-history