# Relationship history for MSHA mine 3503843

Current hierarchy: **Brent  Kerr → Columbia Northwest Recycling Inc → Portable 2**

- 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:** Brent  Kerr → Portable 2; 2010-04-14 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Columbia Northwest Recycling Inc → Portable 2; 2016-01-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brent  Kerr → Columbia Northwest Recycling Inc; 2016-01-02 to current/open; source msha-controller-operator-history