# Relationship history for MSHA mine 3102231

Current hierarchy: **Robbin L  Jones → Wallburg Mulch Sand and Gravel Inc → Blue Pit**

- 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:** Robbin L  Jones et al → Blue Pit; 2006-10-31 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Wallburg Mulch Sand and Gravel Inc → Blue Pit; 2008-03-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robbin L  Jones et al → Wallburg Mulch Sand and Gravel Inc; 2008-03-27 to current/open; source msha-controller-operator-history