# Relationship history for MSHA mine 5001854

Current hierarchy: **Gerald  Hassel → R B Gravel Company → R B Gravel Company**

- 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:** Gerald  Hassel → R B Gravel Company; 1988-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** R B Gravel Company → R B Gravel Company; 2006-08-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gerald  Hassel → R B Gravel Company; 2006-08-12 to current/open; source msha-controller-operator-history