# Relationship history for MSHA mine 0600660

Current hierarchy: **Nancy  Garthwaite → GARF TRUCKING INC → POWERSCREEN CHIEFTAIN 1400**

- 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:** Garf Trucking Inc → POWERSCREEN CHIEFTAIN 1400; 1998-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Nancy  Garthwaite → POWERSCREEN CHIEFTAIN 1400; 1998-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nancy  Garthwaite → Garf Trucking Inc; 1998-07-01 to current/open; source msha-controller-operator-history