# Relationship history for MSHA mine 2602423

Current hierarchy: **Russell  Limb → Progressive Contracting Inc → Portable #4**

- 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:** Russell  Limb → Portable #4; 1991-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Progressive Contracting Inc → Portable #4; 2000-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Russell  Limb → Progressive Contracting Inc; 2000-05-01 to current/open; source msha-controller-operator-history