# Relationship history for MSHA mine 0203236

Current hierarchy: **Delberta Ann  Lamb → Lamb Rock → Wentworth**

- 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

- **controller_controls_mine:** Delberta Ann  Lamb et al → Wentworth; 2009-02-02 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Lamb Rock → Wentworth; 2009-03-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Delberta Ann  Lamb et al → Lamb Rock; 2009-03-30 to current/open; source msha-controller-operator-history