# Relationship history for MSHA mine 0202926

Current hierarchy: **Ron  Hartwigsen → D & R Excavating → D & R 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:** D & R Excavating Inc → D & R Portable; 2001-01-01 to 2004-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Ron  Hartwigsen → D & R Portable; 2001-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ron  Hartwigsen → D & R Excavating Inc; 2001-01-01 to 2004-03-31; source msha-controller-operator-history
- **operator_operates_mine:** D & R Excavating → D & R Portable; 2004-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ron  Hartwigsen → D & R Portable; 2004-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ron  Hartwigsen → D & R Excavating; 2004-04-01 to current/open; source msha-controller-operator-history