# Relationship history for MSHA mine 0203152

Current hierarchy: **Ron  Hartwigsen → D & R Excavating → D & B 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Ron  Hartwigsen → D & B Portable; 2004-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** D & R Excavating → D & B Portable; 2007-01-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ron  Hartwigsen → D & R Excavating; 2007-01-08 to current/open; source msha-controller-operator-history