# Relationship history for MSHA mine 2000701

Current hierarchy: **Smith David L → D L Smith Sand & Gravel Inc → Smith 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

- **operator_operates_mine:** D L Smith Sand & Gravel Inc → Smith Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Smith David L → Smith Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Smith David L → D L Smith Sand & Gravel Inc; 1950-01-01 to current/open; source msha-controller-operator-history