# Relationship history for MSHA mine 4104123

Current hierarchy: **Dorothy  Bartel; Rick  Bartel; Steve  Bartel → B & B Sand & Gravel Inc → B & B SAND & GRAVEL INC NO 2**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **controller_controls_mine:** Dorothy  Bartel et al → B & B SAND & GRAVEL INC NO 2; 1997-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** B & B Sand & Gravel Inc → B & B SAND & GRAVEL INC NO 2; 2000-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dorothy  Bartel et al → B & B Sand & Gravel Inc; 2000-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Rick  Bartel et al → B & B Sand & Gravel Inc; 2000-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Steve  Bartel et al → B & B Sand & Gravel Inc; 2000-01-01 to current/open; source msha-controller-operator-history