# Relationship history for MSHA mine 4503589

Current hierarchy: **Steve  Sandberg → Desert Rock Escavators → Desert Rock Portable**

- 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:** Desert Rock Escavators → Desert Rock Portable; 2005-09-13 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Steve  Sandberg → Desert Rock Portable; 2005-09-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Steve  Sandberg → Desert Rock Escavators; 2005-09-13 to current/open; source msha-controller-operator-history