# Relationship history for MSHA mine 0203244

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

- 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:** Delberta Ann  Lamb et al → Powerscreen; 2009-02-02 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Lamb Rock → Powerscreen; 2009-04-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Delberta Ann  Lamb et al → Lamb Rock; 2009-04-16 to current/open; source msha-controller-operator-history