# Relationship history for MSHA mine 4105256

Current hierarchy: **Dorothy  Bartel; Rick  Bartel; Steve  Bartel → B&B Sand and Gravel Inc. → B&B Sand**

- 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

- **controller_controls_mine:** Rick  Bartel et al → B&B Sand; 1997-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** B&B Sand and Gravel Inc. → B&B Sand; 2017-05-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Rick  Bartel et al → B&B Sand and Gravel Inc.; 2017-05-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Steve  Bartel et al → B&B Sand and Gravel Inc.; 2017-05-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dorothy  Bartel et al → B&B Sand and Gravel Inc.; 2017-05-04 to current/open; source msha-controller-operator-history