# Relationship history for MSHA mine 3400634

Current hierarchy: **Hall Don L → Don L Hall Excavating & Sand Company → Hall Sand Strip & Moon Sand Strip**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Don L Hall Excavating & Sand Company → Hall Sand Strip & Moon Sand Strip; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hall Don L → Hall Sand Strip & Moon Sand Strip; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hall Don L → Don L Hall Excavating & Sand Company; 1950-01-01 to current/open; source msha-controller-operator-history