# Relationship history for MSHA mine 0203090

Current hierarchy: **Dale  Turner → Tombstone Sand & Rock → Walnut Gulch**

- 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

- **controller_controls_mine:** Dale  Turner → Walnut Gulch; 2005-02-28 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Tombstone Sand & Rock → Walnut Gulch; 2005-06-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dale  Turner → Tombstone Sand & Rock; 2005-06-17 to current/open; source msha-controller-operator-history