# Relationship history for MSHA mine 1401520

Current hierarchy: **Cherry Esther M → Delta Sand Inc → DELTA SAND INC**

- 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:** Delta Sand Inc → DELTA SAND INC; 1989-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Cherry Esther M → DELTA SAND INC; 1989-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cherry Esther M → Delta Sand Inc; 1989-04-01 to current/open; source msha-controller-operator-history