# Relationship history for MSHA mine 1601172

Current hierarchy: **Jerry L  Sandifer → Jerry L Sandifer Gravel Company → Pit #4**

- 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:** Jerry L Sandifer Gravel Company → Pit #4; 1988-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Jerry L  Sandifer → Pit #4; 1988-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jerry L  Sandifer → Jerry L Sandifer Gravel Company; 1988-08-01 to current/open; source msha-controller-operator-history